atw - International Journal for Nuclear Power | 03.2021

Ever since its first issue in 1956, the atw – International Journal for Nuclear Power has been a publisher of specialist articles, background reports, interviews and news about developments and trends from all important sectors of nuclear energy, nuclear technology and the energy industry. Internationally current and competent, the professional journal atw is a valuable source of information. www.nucmag.com

Ever since its first issue in 1956, the atw – International Journal for Nuclear Power has been a publisher of specialist articles, background reports, interviews and news about developments and trends from all important sectors of nuclear energy, nuclear technology and the energy industry. Internationally current and competent, the professional journal atw is a valuable source of information.



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nucmag.com<br />

2021<br />

3<br />

ISSN · 1431-5254<br />

32.50 €<br />

Small Modular Reactor<br />

Safety-in-Design<br />

and Perspectives<br />

<strong>Nuclear</strong> <strong>Power</strong> is Dead,<br />

Long Live <strong>Nuclear</strong> Energy!<br />

BREST-OD-300 –<br />

Demonstration of Natural<br />

Safety Technologies

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<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Towards New Reactors and<br />

Reactor Concepts<br />

<strong>Nuclear</strong> energy is often referred to as “dinosaur technology” in discussions in order to characterize it in advance,<br />

beyond a fair discussion. But even this is wrong, because the peaceful use of nuclear energy began about 70 years ago,<br />

in the early 1950s, and it is thus virtually as young as, <strong>for</strong> example, renewable photovoltaics.<br />

The first electricity from nuclear energy was generated in<br />

1948 in an experimental facility. At the Oak Ridge National<br />

Laboratory in the state of Tennessee in the USA, the X-10<br />

reactor was commissioned in 1943 as the world's second<br />

nuclear reactor after the Chicago Pile 1. From 1945, it<br />

served research purposes and was also the first reactor in<br />

the world to supply radioisotopes <strong>for</strong> medical use. The<br />

air-cooled, graphite-moderated reactor offered a wide<br />

range of possibilities <strong>for</strong> research but also technical<br />

applications. In 1948, a small steam generator was<br />

installed, the steam from which provided the drive <strong>for</strong> a<br />

model generator that lit a light bulb <strong>for</strong> the first time in the<br />

same year.<br />

For the first time, electricity from a power plant<br />

turbogenerator was supplied by the EBR-I fast reactor on<br />

20 December 1951; four light bulbs marked the way to<br />

further nuclear power generation.<br />

Because of the many technical options and combinations<br />

offered by nuclear fission, a wide variety of plant<br />

concepts were pursued in the 1960s and 1970s, including a<br />

broad range of applications. At an early stage, those<br />

involved and developers were thinking not only of direct<br />

power generation but also of district heating or the<br />

provision of high-temperature process heat, seawater<br />

desalination and chemical processes and energy storage –<br />

all highly topical subjects today, <strong>for</strong> which experience<br />

and historical documents from nuclear energy development<br />

can provide valuable references, foundations and<br />

elaborations.<br />

As is well known, the developments around the<br />

light water reactor technology have been commercially<br />

successful until today, also because they could fall back on<br />

manifold experiences of conventional power and energy<br />

generation and provided a realizable potential with regard<br />

to the further increasing plant capacities demanded at that<br />

time.<br />

However, in these successful decades since the 1960s –<br />

nuclear energy continues to be one of the most important<br />

low-emission energy sources alongside hydropower, with<br />

a share of around 11 % – other reactor concepts have never<br />

completely lost their importance in research and development.<br />

Comprehensive concept studies, such as the work of<br />

the Generation IV <strong>International</strong> Forum (GIF) in the context<br />

of "Generation IV," were essential in this regard. In 2002,<br />

GIF published the so-called Technology Roadmap, which<br />

describes six reactor types that are considered suitable <strong>for</strong><br />

achieving or meeting the development goals of safety,<br />

sustainability and economic efficiency. But the work on<br />

high-temperature reactor concepts or fast reactors in<br />

China, India and Russia also underlines the continuity, up<br />

to the construction and operation of real pilot plants.<br />

When it comes to concepts <strong>for</strong> the future, a broad<br />

spectrum of developments is on the agenda today. The<br />

change in overall power generation, i.e. initially essentially<br />

characterized by more renewable capacities with unsteady<br />

and unpredictable power feed-in, also requires other<br />

solutions <strong>for</strong> the indispensable “conventional” generation.<br />

Ultimately, power plants or storage solutions must ensure<br />

grid stability and security of supply.<br />

<strong>Nuclear</strong> energy can advantageously cover a broad<br />

power spectrum, if only because of its scalability. What is<br />

new is how the U.S. Department of Energy classifies future<br />

nuclear power plants according to their output into:<br />

p Microreactors from 1 to 20 MWe(lectric)<br />

p Small Modular Reactors – SMR from 20 to 300 MWe<br />

and<br />

p High-power reactors from 300 to 1,000 MWe.<br />

These reactors would cover the currently <strong>for</strong>eseeable<br />

demand <strong>for</strong> new and additional generation capacities in<br />

the best possible way. The “microreactors” are newly<br />

classified. Thus, their small footprint and an expected<br />

construction time of no more than 24 months – DOE<br />

expects 54 months <strong>for</strong> SMRs – make them appear suitable<br />

<strong>for</strong> combination with high-capacity renewable generation<br />

parks, where a source as close to site as possible is needed<br />

to balance volatility.<br />

However, new nuclear power plant developments also<br />

require an appropriate regulatory environment and<br />

infrastructure. Historical experience shows that quasisimultaneous<br />

development of rules and regulations <strong>for</strong><br />

large-scale projects can lead to noticeable delays with their<br />

planning, design, and construction. A coordinated and<br />

systematic approach is needed here. The fact that a suitable<br />

regulatory environment and a safe infrastructure <strong>for</strong> new<br />

nuclear power plant projects can be set up and implemented<br />

in a targeted and speedy manner is impressively<br />

demonstrated by the four new nuclear power plants built<br />

in the United Arab Emirates. Within just a decade from the<br />

final construction decision until now, the commercial<br />

commissioning of the first of four 1,400 MW nuclear power<br />

plant units at the Barakah site, the necessary reliable<br />

environment has been established. Also, worldwide, the<br />

IAEA – <strong>International</strong> Atomic Energy Agency – today<br />

supports 30 countries in building infrastructure <strong>for</strong> the<br />

desired entry into peaceful use of nuclear energy – as a<br />

sustainable, low-emission energy source with economic<br />

and consumer-oriented generation.<br />

Christopher Weßelmann<br />

– Editor in Chief –<br />

3<br />


Editorial<br />

Towards New Reactors and Reactor Concepts

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Contents<br />

4<br />


Issue 3<br />

2021<br />

May<br />

Editorial<br />

Towards New Reactors and Reactor Concepts . . . . . . . . . . . . . . 3<br />

Inside <strong>Nuclear</strong> with NucNet<br />

Lessons Learned<br />

From the March 2011 Fukushima-Daiichi <strong>Nuclear</strong> Accident . . . . . 6<br />

Calendar 8<br />

Feature | Research and Innovation<br />

Small Modular Reactor Safety-in-Design and Perspectives . . . . . . .9<br />

Akira Tokuhiro, Chireuding Zeliang and Yi Mi<br />

Cover:<br />

Site layout <strong>for</strong> the SMR nuclear site complex<br />

by MOLTEX Energy. A feasibility report <strong>for</strong> Canada<br />

with the MOLTEX concept under review has just been<br />

published.<br />

Contents:<br />

2020-year-in review –<br />

The NuScale Energy Exploration Center,<br />

Copyright NuScale<br />

Did you know? 17<br />

Q&A with the Ministry of Natural Resources Canada<br />

The <strong>Nuclear</strong> Innovation Policy of Canada . . . . . . . . . . . . . . . . 18<br />

Interview with John Gorman<br />

“I am Personally Very Excited About Canadas’s Positioning<br />

as a Tier One <strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover<br />

in Small Modular Reactors“ . . . . . . . . . . . . . . . . . . . . . . . 21<br />

Serial | Major Trends in Energy Policy and <strong>Nuclear</strong> <strong>Power</strong><br />

<strong>Nuclear</strong> <strong>Power</strong> is Dead, Long Live <strong>Nuclear</strong> Energy! . . . . . . . . . . 25<br />

Simon Wakter<br />

Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster . . . . . . . . . . . . . . . . 29<br />

Herbert Saurugg<br />

A Role <strong>for</strong> <strong>Nuclear</strong> in the Future Dutch Energy Mix . . . . . . . . . 35<br />

Bojan Tomic and Mario van der Borst<br />

Operation and New Build<br />

BREST-OD-300 – Demonstration of Natural Safety Technologies . 41<br />

Vadim Lemehov and Valeriy Rachkov<br />

At a Glance<br />

<strong>Nuclear</strong> Innovation Alliance (NIA) . . . . . . . . . . . . . . . . . . . . 46<br />

Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German<br />

Technology Pressure Water Reactors (Light and Heavy Water) . . 48<br />

Franz Stuhlmüller and Rafael Macián-Juan<br />

IAEA Approach to Review the Applicability of the Safety<br />

Standards to Small Modular Reactors . . . . . . . . . . . . . . . . . . 56<br />

Paula Calle Vives, Kristine Madden and Vesselina Ranguelova<br />

Research and Innovation<br />

A Zero-power Facility as a Multi-fold Opportunity to Support<br />

Quick Progress in Innovative Reactor Development . . . . . . . . . 59<br />

Bruno Merk, Dzianis Litskevich, Anna Detkina, Greg Cartland-Glover, Seddon Atknison and Mark Bankhead<br />

The Thorium Network – An Introduction to Blockchain <strong>for</strong> SMRs . 65<br />

Dian Kemp, Hulmo Christiaansen, Yvette Kemp and Jeremiah E. Josey<br />

Kazatomprom’s Digital Trans<strong>for</strong>mation Projects . . . . . . . . . . . 68<br />

Aliya Akzholova<br />

Studies on Per<strong>for</strong>mance and Degradation Stability<br />

of Chemically Degraded <strong>Nuclear</strong> Graded Ion Exchange<br />

Materials by Application of Radio Analytical Technique . . . . . . 71<br />

Pravin Singare<br />

News 78<br />

<strong>Nuclear</strong> Today<br />

As Reactor Technologies Advance,<br />

<strong>Nuclear</strong> Will Still Need its Environmental Champions . . . . . . . . 82<br />

Imprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42<br />


<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

5<br />

Feature<br />

Research and Innovation<br />

9 Small Modular Reactor Safety-in-Design<br />

and Perspectives<br />


Akira Tokuhiro, Chireuding Zeliang and Yi Mi<br />

Interview with John Gorman<br />

21 “I am Personally Very Excited About Canadas’s Positioning<br />

as a Tier One <strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover<br />

in Small Modular Reactors“<br />

Serial | Major Trends in Energy Policy and <strong>Nuclear</strong> <strong>Power</strong><br />

25 <strong>Nuclear</strong> <strong>Power</strong> is Dead, Long Live <strong>Nuclear</strong> Energy!<br />

Simon Wakter<br />

Energy Policy, Economy and Law<br />

29 Europe on the Road to a Major Disaster<br />

Herbert Saurugg<br />

Operation and New Build<br />

41 BREST-OD-300 – Demonstration of Natural Safety Technologies<br />

Vadim Lemehov and Valeriy Rachkov<br />

Environment and Safety<br />

56 IAEA Approach to Review the Applicability of the Safety Standards<br />

to Small Modular Reactors<br />

Paula Calle Vives, Kristine Madden and Vesselina Ranguelova<br />


<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

6<br />


Lessons Learned From the March 2011<br />

Fukushima-Daiichi <strong>Nuclear</strong> Accident<br />

The official Japanese report into the accident 10 years ago pointed to ‘a multitude of errors and<br />

willful negligence’, but what steps have been taken to prevent a repeat?<br />

Although triggered by a cataclysmic earthquake and<br />

tsunami, the subsequent accident at the Fukushima-Daiichi<br />

nuclear power station 10 years ago cannot be regarded as a<br />

natural disaster.<br />

It was, the Fukushima <strong>Nuclear</strong> Accident Independent<br />

Investigation Commission concluded in its official report, 1 a<br />

profoundly manmade disaster – one that could and should<br />

have been <strong>for</strong>eseen and prevented. And its effects could<br />

have been mitigated by a more effective human response.<br />

Kiyoshi Kurokawa, chairman of the commission, was<br />

blunt in his assessment of the root causes, pointing to a<br />

multitude of errors and willful negligence that left the<br />

Fukushima-Daiichi facility unprepared <strong>for</strong> the events of<br />

11 March 2011. There were “serious deficiencies” in the<br />

response to the accident by plant owner and operator Tokyo<br />

Electric <strong>Power</strong> Company, regulators and the government.<br />

Mr Kurokawa said what the commission’s report could<br />

not fully convey – especially to a global audience – was the<br />

mindset that supported the negligence behind this disaster.<br />

“What must be admitted – very painfully – is that this<br />

was a disaster ‘Made in Japan’, he said. “Its fundamental<br />

causes were to be found in the ingrained conventions of<br />

Japanese culture: our reflexive obedience; our reluctance<br />

to question authority; our devotion to ‘sticking with the<br />

programme’; our groupism; and our insularity.”<br />

The report pointed to organisational problems within<br />

Tepco. Had there been a higher level of knowledge,<br />

training, and equipment inspection related to severe<br />

accidents, and had there been specific instructions given to<br />

the onsite workers concerning the state of emergency, a<br />

more effective accident response would have been possible.<br />

“Neither [Tepco or the regulators] had taken steps to<br />

put preventive measures in place,” the report concluded.<br />

“It was this lack of preparation that led to the severity of<br />

this accident.”<br />

The direct causes of the accident were all <strong>for</strong>eseeable.<br />

The power station was incapable of withstanding the earthquake<br />

and tsunami that hit on that day. The operator, Tokyo<br />

Electric <strong>Power</strong> Company (Tepco), the regulatory bodies (the<br />

<strong>Nuclear</strong> and Industrial Safety Agency and the <strong>Nuclear</strong> Safety<br />

Commission) and the government body promoting the<br />

nuclear power industry (the ministry of economy, trade and<br />

industry, or METI), all failed to correctly develop the most<br />

basic safety requirements – such as assessing the probability<br />

of damage, preparing <strong>for</strong> containing collateral damage from<br />

such a disaster, and developing evacuation plans <strong>for</strong> the<br />

public in the case of a serious radiation release.<br />

As early as 1981, NISA had required that nuclear<br />

operators assess the anti-seismic safety of their sites<br />

according to new guidelines – the so-called “anti-seismic<br />

backcheck.”<br />

In March 2008, Tepco submitted an interim anti- seismic<br />

backcheck report on Unit 5 of Fukushima-Daiichi, saying<br />

the unit was safe.<br />

In 2009, NISA accepted the contents of the interim<br />

report, even though the scope of the assessment included<br />

the reactor building and only seven of many other<br />

important safety installations and equipment.<br />

In June 2009, similar reports <strong>for</strong> Units 1 to 4 and 6 were<br />

submitted, but these were similarly limited.<br />

The official deadline <strong>for</strong> the backchecks was June 2009,<br />

but according to the commission, Tepco made the decision<br />

“internally and unilaterally” to reschedule the deadline to<br />

January 2016.<br />

Since 2006, the regulators and Tepco had also been<br />

aware of the risk that a total outage of electricity at the<br />

Fukushima Daiichi plant might occur if a tsunami were to<br />

reach the level of the site. They were also aware of the risk<br />

of reactor core damage from the loss of seawater pumps in<br />

the case of a tsunami larger than assumed in the Japan<br />

Society of Civil Engineers estimation. NISA knew that<br />

Tepco had not prepared any measures to lessen or eliminate<br />

the risk, but failed to provide specific instructions to<br />

remedy the situation.<br />

The report’s verdict on Tepco and the regulators was<br />

damning. “They either intentionally postponed putting<br />

safety measures in place, or made decisions based on their<br />

organisation’s self-interest – not in the interest of public<br />

safety.”<br />

An IAEA report 2 echoed these findings. It said a major<br />

factor that contributed to the accident was the widespread<br />

assumption in Japan that its nuclear power plants<br />

were so safe that an accident of this magnitude was<br />

simply unthinkable. This assumption was accepted by<br />

nuclear plant operators and was not challenged by<br />

regulators or by the government. As a result, Japan was not<br />

sufficiently prepared <strong>for</strong> a severe nuclear accident in<br />

March 2011.<br />

“The Fukushima-Daiichi accident exposed certain<br />

weaknesses in Japan’s regulatory framework,” the IAEA<br />

said. “Responsibilities were divided among a number of<br />

bodies, and it was not always clear where authority lay.”<br />

The Response In Japan<br />

Japan moved quickly to resolve serious problems around<br />

nuclear regulation, safety and accident readiness.<br />

The <strong>Nuclear</strong> Regulatory Authority was <strong>for</strong>med on<br />

19 September 2012 from the <strong>Nuclear</strong> Safety Commission<br />

(NSC), which came under the authority of the cabinet, and<br />

the <strong>Nuclear</strong> and Industry Safety Agency (NISA), which was<br />

under METI. The problem lay in the fact that METI was<br />

also responsible <strong>for</strong> the promotion of nuclear power,<br />

leading to accusations of a serous conflict of interest. The<br />

NRA was established as an independent entity under the<br />

environment ministry.<br />

According to legislation establishing the NRA, new<br />

nuclear safety rules were to be completed within<br />

10 months. The NRA’s first chairman, Shunichi Tanaka,<br />

1 https://www.nirs.org/wp-content/uploads/fukushima/naiic_report.pdf<br />

2 https://www.iaea.org/sites/default/files/fr-brochure.pdf<br />

Inside <strong>Nuclear</strong> with NucNet<br />

Lessons Learned From the March 2011 Fukushima-Daiichi <strong>Nuclear</strong> Accident

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

said that the authority would undertake a radical review of<br />

existing safety standards.<br />

In January 2013 the NRA presented a draft outline of<br />

new safety standards 3 <strong>for</strong> nuclear power plants, including<br />

countermeasures against severe accidents and criteria <strong>for</strong><br />

evacuating areas around plants during an emergency.<br />

The standards were approved in June 2013 4 and became<br />

effective on 8 July 2013. The NRA began accepting<br />

applications <strong>for</strong> reactor restarts. At this point only two of<br />

Japan’s 42 commercial reactors, Ohi-3 and Ohi-4, had<br />

restarted since the accident.<br />

The standards consisted of severe accident measures<br />

based on the accident at Fukushima-Daiichi, together with<br />

design standards and requirements in each area of nuclear<br />

plant safety.<br />

Measures included a requirement to outfit plants with<br />

backup control rooms away from reactor buildings, install<br />

new pressure vents capable of filtering out radioactive<br />

gasses, and rein<strong>for</strong>ce protective structures.<br />

Operators deployed movable alternative equipment<br />

such as power supply vehicles so that plants could be<br />

operated safely <strong>for</strong> at least seven days without outside help.<br />

One of the severe accident measures was a requirement<br />

to build a so-called “specific safety facility” on nuclear<br />

plant sites, on the assumption of core damage in a reactor,<br />

with terrorism a possible cause. Terrorism would include<br />

an intentional aircraft strike.<br />

The safety facility had to be situated 100 metres or more<br />

from the reactor building, so it would not be destroyed in<br />

the same event. A secondary control room was required<br />

within the safety facility.<br />

Mr Tanaka said the new rules represented “the<br />

beginning of real [nuclear] regulation in Japan”.<br />

The IAEA said Japan has re<strong>for</strong>med its regulatory system<br />

to better meet international standards. Regulators have<br />

clearer responsibilities and greater authority. The new<br />

regulatory framework has been reviewed by an IAEA peer<br />

review mission. Emergency preparedness and response arrangements<br />

have also been strengthened, the agency said.<br />

Japan’s <strong>Nuclear</strong> Status<br />

Japan has 62 nuclear power units, but shut down all 42<br />

that were operating at the time after Fukushima-Daiichi.<br />

Thirty-three units have a licence to operate, although<br />

be<strong>for</strong>e units return to service they need to meet the NRA’s<br />

new safety standards.<br />

Nine units have been returned to service, but five of<br />

those are offline again <strong>for</strong> regular maintenance or<br />

upgrades. The four reactors that are online are Sendai-1,<br />

Sendai-2, Genkai-3 and Ohi-4.<br />

Be<strong>for</strong>e the Fukushima-Daiichi accident Japan’s nuclear<br />

fleet generated about 30 % of the country’s electricity.<br />

According to the <strong>International</strong> Atomic Energy Agency that<br />

figure was about 7.5 % in 2019.<br />

Governments with established nuclear-energy<br />

programmes responded in part by conducting safety<br />

checks, including comprehensive “stress tests” that<br />

scrutinised a facility’s ability to withstand everything from<br />

an earthquake and tsunami to a terrorist assault.<br />

Additional backup sources of electrical power and<br />

supplies of water have been installed, and protection<br />

against extreme external events strengthened. In some<br />

cases, organisational and regulatory systems have been<br />

re<strong>for</strong>med.<br />

Safety reassessments concluded that facilities examined<br />

offer a safety level that is sufficient, and no immediate<br />

shutdown was required.<br />

The IAEA emphasises that nuclear safety remains the<br />

responsibility of an individual country, but says nuclear<br />

accidents can transcend borders and the Fukushima-<br />

Daiichi accident “underlined the importance of international<br />

cooperation”.<br />

In Europe, all nuclear power plants in the EU underwent<br />

stress tests and peer reviews in 2011 and 2012. Many<br />

other countries and territories also conducted comprehensive<br />

nuclear risk and safety assessments, based on<br />

the EU stress-test model. These include Switzerland and<br />

Ukraine (both of which fully participated in the EU stress<br />

tests), Armenia, Turkey, Russia, Taiwan, Japan, South<br />

Korea, South Africa and Brazil.<br />

In China, which had aspirations to build up to 100 new<br />

nuclear units by 2030, plans were put on hold. Premier<br />

Wen Jiabao announced the suspension of the approval of<br />

new nuclear power projects and called <strong>for</strong> a com prehensive<br />

safety assessment of Chinese nuclear power facilities.<br />

Beijing ultimately decided to lift the moratorium on<br />

construction of new nuclear power plants in October 2012.<br />

The state council said safety investigations had shown that<br />

“nuclear security is guaranteed in China.”<br />

In the US, the <strong>Nuclear</strong> Regulatory Commission ordered<br />

in March 2012 that nuclear power plants meet specific<br />

deadlines <strong>for</strong> safety checks and upgrades. 7<br />

The checks<br />

included maintaining key safety functions even if installed<br />

electricity sources fail; installing additional equipment to<br />

monitor spent fuel pool water levels; and installing or<br />

improving systems to safely vent pressure during an<br />

accident. The NRC also asked all US plants <strong>for</strong> in<strong>for</strong>mation<br />

on comprehensive earthquake and flooding hazard<br />

analyses.<br />

Author<br />

David Dalton<br />

NucNet –<br />

The Independent Global <strong>Nuclear</strong> News Agency<br />

Bruxelles, Belgium<br />

www.nucnet.org<br />


The <strong>International</strong> Response<br />

Three months after the accident, the <strong>International</strong> Atomic<br />

Energy Agency hosted a ministerial conference on nuclear<br />

safety. This paved the way <strong>for</strong> the unanimous endorsement<br />

of an IAEA action plan 5<br />

that has led to international<br />

collaboration toward strengthening global nuclear safety. 6<br />

3 https://www.nucnet.org/news/japan-s-regulator-unveils-proposed-new-safety-measures<br />

4 https://www.nucnet.org/news/japan-s-regulator-approves-new-safety-guidelines<br />

5 https://www.iaea.org/topics/nuclear-safety-action-plan<br />

6 https://www.iaea.org/newscenter/news/four-years-of-progress-action-plan-on-nuclear-safety<br />

7 https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/japan-events.html<br />

Inside <strong>Nuclear</strong> with NucNet<br />

Lessons Learned From the March 2011 Fukushima-Daiichi <strong>Nuclear</strong> Accident

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

8<br />


Calendar<br />

2021<br />

Online Conference 04.05.2021<br />

2021 KTG Annual Meeting. Berlin, Germany, KTG,<br />

www.ktg.org<br />

Online Conference 10.05. – 15.05.2021<br />

FEC 2020 – 28 th IAEA Fusion Energy Conference.<br />

Nice, France, IAEA, www.iaea.org<br />

18.05. – 20.05.2021<br />

<strong>Power</strong> Uzbekistan 2021 – 15 th Anniversary<br />

<strong>International</strong> Exhibition on Energy.<br />

Tashkent, Uzbekistan, Iteca Exhibitions,<br />

www.power-uzbekistan.uz<br />

Online Conference 04.08. – 06.08.2021<br />

ICONE 28 – 28 th <strong>International</strong> Conference on<br />

<strong>Nuclear</strong> Engineering. <strong>Nuclear</strong> Energy the Future<br />

Zero Carbon <strong>Power</strong>. ASME, https://event.asme.org<br />

25.08. – 27.08.2021<br />

KONTEC 2021 – 15 th <strong>International</strong> Symposium<br />

“Conditioning of Radioactive Operational &<br />

Decommissioning Wastes”. Dresden, Germany,<br />

atm, www.kontec-symposium.de<br />

25.08. – 03.09.2021<br />

The Frédéric Joliot/Otto Hahn Summer School<br />

on <strong>Nuclear</strong> Reactors “Physics, Fuels and Systems”.<br />

Aix-en-Provence, France, CEA & KIT, www.fjohss.eu<br />

29.08. - 03.09.2021<br />

PSA 2021 – <strong>International</strong> Topical Meeting on<br />

Probabilistic Safety Assessment and Analysis.<br />

ANS, Columbus, OH, USA, www.psa.ans.org<br />

Postponed to 24.10. – 28.10.2021<br />

TopFuel 2021. Santander, Spain, ENS,<br />

https://www.euronuclear.org/topfuel2021<br />

26.10. – 28.10.2021<br />

VGB Conference Chemistry. Ulm, Germany, VGB<br />

<strong>Power</strong>Tech, www.vgb.org<br />

01.11. – 12.11.2021<br />

COP26 – UN Climate Change Conference.<br />

Glascow, Scotland, www.ukcop26.org<br />

Postponed to 30.11. – 02.12.2021<br />

Enlit (<strong>for</strong>mer European Utility Week and<br />

POWERGEN Europe). Milano, Italy,<br />

www.enlit-europe.com<br />

30.11. – 02.12.2021<br />

WNE2021 – World <strong>Nuclear</strong> Exhibition. Paris,<br />

France, Gifen, www.world-nuclear-exhibition.com<br />

Postponed to 30.08. – 03.09.2021<br />

<strong>International</strong> Conference on Operational Safety<br />

of <strong>Nuclear</strong> <strong>Power</strong> Plants. Beijing, China, IAEA,<br />

www.iaea.org<br />

2022<br />

Online Conference 19.05. – 20.05.2021<br />

Small Modular Reactors (SMR). Prospero,<br />

www.prosperoevents.com<br />

Cancelled due to COVID 30.05. – 05.06.2021<br />

BEPU2020 – Best Estimate Plus Uncertainty<br />

<strong>International</strong> Conference, Giardini Naxos.<br />

Sicily, Italy, NINE, www.nineeng.com<br />

Online Conference 07.09. – 09.09.2021<br />

Management systems <strong>for</strong> a sustainable nuclear<br />

supply chain. Helsinki, Finland, Foratom,<br />

https://events.<strong>for</strong>atom.org/mstf2021<br />

Hybrid Conference 08.09. – 10.09.2021<br />

3 rd <strong>International</strong> Conference on Concrete<br />

Sustainability. Prague, Czech Republic, fib,<br />

www.fibiccs.org<br />

08.09. – 10.09.2021<br />

World <strong>Nuclear</strong> Association Symposium 2021.<br />

London, UK, WNA, www.wna-symposium.org<br />

Postponed to 28.02. – 04.03.2022<br />

20 th WCNDT – World Conference on<br />

Non-Destructive Testing. Incheon, Korea,<br />

The Korean Society of Nondestructive Testing,<br />

www.wcndt2020.com<br />

06.03. – 11.03.2022<br />

NURETH19 – 19 th <strong>International</strong> Topical Meeting<br />

on <strong>Nuclear</strong> Reactor Thermal Hydraulics. SCK·CEN,<br />

Brussels, Belgium, www.events.sckcen.be<br />

22.09. – 23.09.2021<br />

VGB Congress 100 PLUS. Essen, Germany, VGB<br />

<strong>Power</strong>Tech, www.vgb.org<br />

Online Conference 01.06. – 02.06.2021<br />

<strong>Nuclear</strong> <strong>Power</strong> Plants IV. Expo & VIII. Summit<br />

(NPPES). Istanbul, Turkey, INPPES Expo,<br />

www.nuclearpowerplantsexpo.com<br />

Online Conference 02.06. – 05.06.2021<br />

HTR2021 – 10 th <strong>International</strong> Conference<br />

on High Temperature Reactor Technology.<br />

Yogyakarta, Indonesia, Indonesian <strong>Nuclear</strong> Society,<br />

www.htr2020.org<br />

Online Conference 07.06. – 09.06.2021<br />

<strong>Nuclear</strong> Energy Assembly. NEI,<br />

www.nei.org<br />

Online Conference 14.06. – 16.06.2021<br />

2021 ANS Annual Meeting. ANS, www.ans.org<br />

26.09. – 30.09.2021<br />

RRFM 2021 – European Research Reactor<br />

Conference. ENS, Helsinki, Finland,<br />

www.euronuclear.org<br />

27.09. – 30.09.2021<br />

European <strong>Nuclear</strong> Young Generation Forum<br />

(ENYGF). Tarragona, Spain, ENYGF, www.enygf.org<br />

27.09. – 01.10.2021<br />

NPC 2021 <strong>International</strong> Conference on <strong>Nuclear</strong><br />

Plant Chemistry. Antibes, France, SFEN Société<br />

Française d’Energie Nucléaire,<br />

www.sfen-npc2021.org<br />

04.10. – 05.10.2021<br />

AtomExpo 2021. Sochi, Russia, Rosatom,<br />

http://2021.atomexpo.ru/en<br />

29.03. – 30.03.2022<br />

KERNTECHNIK 2022.<br />

Leipzig, Germany, KernD and KTG,<br />

www.kerntechnik.com<br />

04.04. – 08.04.2022<br />

<strong>International</strong> Conference on Geological<br />

Repositories. Helsinki, Finland, EURAD,<br />

www.ejp-eurad.eu<br />

Postponed to Spring 2022<br />

4 th CORDEL Regional Workshop – Harmonization<br />

to support the operation and new build of NPPs<br />

including SMR. Lyon, France, World <strong>Nuclear</strong><br />

Association, https://events.<strong>for</strong>atom.org<br />

Online Conference 23.06. – 24.06.2021<br />

Maintenance in <strong>Power</strong> Plants 2021.<br />

VGB <strong>Power</strong>Tech e.V., www.vgb.org<br />

Online Conference 20.07. – 22.07.2021<br />

POWER 2021. ASME, www.event.asme.org<br />

Online Conference 03.08.-04.08.<br />

and 10.08.-11.08.2021<br />

<strong>International</strong> Uranium Digital Conference 2021.<br />

AusIMM, www.ausimm.com<br />

Postponed – final date and location<br />

to be determined<br />

ICEM 2021 – <strong>International</strong> Conference on<br />

Environmental Remediation and Radioactive<br />

Waste Management. ANS, www.asme.org<br />

16.10. – 20.10.2021<br />

ICAPP 2021 – <strong>International</strong> Conference on<br />

Advances in <strong>Nuclear</strong> <strong>Power</strong> Plants. Khalifa<br />

University, Abu Dhabi, United Arab Emirates,<br />

www.icapp2020.org<br />

Postponed to 04.05. – 06.05.2022<br />

NUWCEM 2022 – <strong>International</strong> Symposium on<br />

Cement-Based Materials <strong>for</strong> <strong>Nuclear</strong> Wastes.<br />

Avignon, France, SFEN, www.sfen-nuwcem2021.org<br />

This is not a full list and may be subject to change.<br />


<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Small Modular Reactor<br />

Safety-in-Design and Perspectives<br />

Akira Tokuhiro, Chireuding Zeliang and Yi Mi<br />

Across the public, nuclear power and global energy sectors, there are various degrees of interest in next and<br />

near-generation micro- to small, modular reactors (MMR, SMR) 1 . The ongoing interests, here defined in terms of<br />

commercial and national technology developments, policy documents (roadmaps, action plans, etc.), various levels<br />

and means of “investments”, are intended to support and facilitate development of select advanced reactor concepts<br />

and demonstration units. The current portfolio of SMRs and MMRs is relative to the current, global fleet; mostly larger<br />

scale nuclear plants (Generation III and III+ designs) currently under construction and/or operating. These legacy<br />

designs largely meet the electricity demand in nations with robust socio-economic development rates. Both the<br />

operating plants and those in various stages of development are included in a “pan-global, nuclear portfolio”, touted (in<br />

the “24/7/365” social media) to address and mitigate the negative impacts of climate change. While there are reasons<br />

to “worry” about the lack of <strong>for</strong>esight, preventative preparedness and response to address the cliff-edge impacts of climate<br />

change, the goal here is not to argue climate change nor policies/developments in national commitments to a<br />

lower or net-zero carbon economies of scale. If anything, climate change can be construed as human society’s inability<br />

to exercise a paradigm shift – in effect, a linear extrapolation from 150+ years of industrialization based on fossil fuels<br />

and release of effluents without consequences. Along the way, we <strong>for</strong>got to ask what can happen and how can it happen.<br />

The consequences are here and imminent (“urgent”), as expressed by climate change leaders, Greta Thunberg, and<br />

others. Nature is suffering in our age of our Anthropocene.<br />

With this in mind, the article here will review a number of<br />

ongoing micro- to small, modular reactors concepts, but<br />

from the perspective of engineering and design development<br />

so that the design is completed. While engineered<br />

and designed features hold much interest to those with<br />

engineering and R&D backgrounds, one might argue that<br />

if nuclear energy is to serve in transition and/or as a<br />

solution to aspirational economies of scale that mitigate<br />

and reduce the negative impacts of climate change, nuclear<br />

reactor designs need to be complete, prudently financed<br />

and “constructable”, because ultimately they serve to<br />

generate electricity that the public expects and demands.<br />

Some 70 years ago in nuclear history, then U.S. President<br />

Dwight Eisenhower appeared at the United Nations (1953)<br />

and spoke on, “Atoms <strong>for</strong> Peace”. Subsequently, in the then<br />

short list of post-WWII developed and developing nations,<br />

there was rapid development, and selection process of<br />

Generation I and II nuclear concepts. Many of these are<br />

part of the 440 or so nuclear power plants operating today.<br />

1 Designs, Legacy and Processes<br />

A few words about the design and engineering process of<br />

new/advanced reactor concepts is in order. Perhaps owing<br />

to the lead author’s educational legacy, it is not something<br />

that I remember explicitly learning during my nuclear<br />

engineering education. That said, there are established<br />

processes within nuclear vendors (manufacturers) that<br />

remain proprietary. These practices do not necessarily<br />

make it into university classrooms. My observation has<br />

been that seasoned professionals from the nuclear sector<br />

do not transition late in their career, to university nuclear<br />

engineering programs/classrooms. There can thus be a<br />

knowledge transfer gap, from the reactor vendor to the<br />

classroom.<br />

The article here on advanced reactor concepts and<br />

SMRs/MMRs, is based on the assumption that completing<br />

the design is of utmost importance, and that the design<br />

process takes time and requires sufficient and sustained<br />

funding because the key high-level task is, iterative<br />

system design. That is, engineering system design, wherein<br />

systems and subsystems are coupled, require iterative<br />

design optimization. This is certainly the case in nuclear<br />

reactor design.<br />

So, we note that SMRs, like many nuclear reactors are<br />

generally designed from the reactor core, outward in terms<br />

of various essential and supporting systems; that is, the<br />

primary, secondary systems and beyond. In fact, one could<br />

say <strong>for</strong> SMRs, the design regions of interest extend all the<br />

way to the emergency planning zone (EPZ), since in<br />

principle, a SMR’s EPZ should be related to, “very<br />

small probability (keep reading) but a high consequence”,<br />

hypothetical accidents. One can say that increasingly<br />

Generation IV (or advanced) reactor concepts are expected<br />

to have very small hypothetical probability with respect to<br />

design basis and beyond design basis accidents (DBA,<br />

BDBA), and features that substantiate means to address<br />

Fukushima (Daichi) type situations. In fact, the design<br />

itself is expected to have a number of safety-in-design<br />

features so that the commonly cited metrics such as, “core<br />

damage frequency” (CDF) and/or “early release frequency”<br />

(ERF), are typically, smaller than 1E-06 2 , if not 1E-08. (We<br />

note here that probabilities – less than say, 1E-09, 1E-10 or<br />

smaller may not hold regulatory meaning or significance.)<br />

Further, other than these small probabilities, observance<br />

or adherence to safety-in-design philosophies/principles<br />

as described in INSAG-10 [14], and “goodness” in design<br />

such that no human intervention is required <strong>for</strong> durations<br />

of time beyond “event” initiation (i.e. first 24, 48, 72 hours,<br />

etc.), detailed in<strong>for</strong>mation on accident progression/<br />

evolution, may appear as aspirational or embedded in the<br />

design features and functions, without open access to the<br />

technical details. Open access of detailed technical<br />

in<strong>for</strong>mation may not be possible; thus, it is not current<br />

practice.<br />

With the above design engineering process and metrics<br />

in mind, let us look at the micro- to small modular reactor<br />

9<br />


1 The term, SMR, is used to be inclusive of Small and Micro Modular Reactor concepts and designs.<br />

2 This notation is used instead of a superscript that may appear visibly small (1 x 10 -6 ).<br />

Feature<br />

Small Modular Reactor Safety-in-Design and Perspectives ı Akira Tokuhiro, Chireuding Zeliang and Yi Mi

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


concepts currently under various states of development.<br />

We note that since a number of overview articles on SMR/<br />

MMR reactor concepts exist, this article is not intended to<br />

be such. Instead we thought to reveal some of the not so<br />

obvious aspects of safety-in-design, that various advanced<br />

reactor designers may adopt to varying degrees. First <strong>for</strong><br />

brevity and utility, we cite some of the key documents<br />

below as a starting point into the various aspects<br />

surrounding SMRs as follows:<br />

p On safety-in-design, references [1, 7, 14, 17(US only),<br />

23, 24, 30]<br />

p On licensing and regulatory aspects of SMRs, reference<br />

[3, 15, 19, 22]<br />

p Overview and advances of SMR, reference [2, 6, 9, 16,<br />

31, 33, 36, 40]<br />

p Specifically passive safety systems within safety-indesign,<br />

references [8, 20, 32]<br />

p Nuscale, SMART, IRIS, CAREM, ESBWR, AP1000<br />

specific starting documents, reference [10, 11, 12, 13,<br />

21 (NuScale EPZ), 28, 29]. Note that the ESBWR and<br />

AP1000 are Generation III/III+, large-scale plant<br />

designs from which lessons learned are realized in SMR<br />

designs.<br />

p General principles in nuclear design and economics,<br />

references [4 (economics),18, 25, 26]<br />

2 Back to the future with nuclear energy?<br />

In a manner similar to many early nuclear reactor<br />

concepts in the late 1950s, early 1960s, there are many<br />

micro- to small, modular reactor concepts. However, with<br />

approximately 60 years of complete design experience,<br />

operational experience, lessons learned from three major<br />

severe accidents, (along with other recorded events),<br />

unrestrained cost increases, regulatory compliance burdens,<br />

anti-nuclear sentiments and advances in computer- based<br />

engineering, recent advanced reactor designs hold consensus<br />

expectations in safety, non- proliferation and<br />

economics. It goes without much declaration that nuclear<br />

energy is often questioned and compared to other <strong>for</strong>ms of<br />

energy (including renewable energy sources) and as a<br />

matter of regional to national energy policy. In recent years,<br />

public acceptance of any risk-inherent technology, processes,<br />

production and consumption – a composite portfolio<br />

of social license, advocacy and questionable objectivity<br />

issues, are fiercely fought with fervent banter in social<br />

media domains. Everyone has an opinion.<br />

<strong>Nuclear</strong> energy and new micro- to small, modular<br />

reactor concepts are not benign from socio-technical<br />

scrutiny, most recently in the global debate on whether<br />

nuclear energy is a partial to full solution to counter the<br />

increasingly emerging evidence on the negative impacts of<br />

climate change.<br />

2.1 The micro- to small, modular reactor<br />

concepts<br />

<strong>Nuclear</strong> reactors are traditionally classified in terms of the<br />

following technical features. These features are high-level<br />

decisions made by its originators. They are: 1) neutron<br />

spectrum, 2) related type of neutron moderation, 3) type<br />

of coolant, 4) fuel type and core configuration. We will use<br />

the same approach <strong>for</strong> consistency. We note Hussein [40]<br />

review that used an expanded classification based on<br />

200+ cited references.<br />

We limit our coverage below to SMR design concepts<br />

of thermal power (output) magnitude that feature conventional<br />

or unique energy conversion system design, utilizing<br />

a liquid-based energy transport system from a defined core<br />

configuration. The core and energy transport system<br />

should fulfill the basic functions as follows: startup (to<br />

criticality), (transition to) steady-state operation at a<br />

targeted power, transition up or down from a given power<br />

setting to another, intended shutdown, emergency shutdown<br />

and post-shutdown decay heat energy removal (to<br />

cold shutdown state).<br />

In this regard, micro-modular reactor concepts (MMR)<br />

are even simpler in design than many SMR concepts<br />

because the thermal power output is approximately an<br />

order of magnitude smaller than SMR (i.e. ~O (5 MWth)<br />

per reactor core vs. ~O (50 MWth)) per reactor core] and<br />

as such, the corresponding means of reactivity control are<br />

reduced accordingly. With respect to MMR safety-indesign,<br />

post-shutdown energy removal mechanisms are<br />

predominantly passive such that air or a large volume of<br />

water, serves as the ultimate heat sink <strong>for</strong> decay heat.<br />

Energy conversion systems are correspondingly modular<br />

in design and may feature reduced coupling to reactor core<br />

control (and thus operations) such that the sole output is<br />

electricity and/or thermal energy. With such simple design<br />

and limited functions, the thermal-hydraulic “parameter<br />

space” is correspondingly small, such that conventional<br />

means of control (analog and/or digital) can be used <strong>for</strong><br />

monitoring, prognostics and diagnostics. The 2020 release<br />

of the IAEA “book” on SMRs/MMRs contains 6 MMR concepts.<br />

A concise, descriptive summary of the announced<br />

MMR concepts is given below.<br />

1) Energy Well (Rez, Czech Republic) – is a high<br />

temperature (core inlet, 650 °C; outlet, 700 °C) molten<br />

salt FLiBe cooled and moderated, with targeted thermal<br />

and electrical power output, 20MWt/8 MWe. The once<br />

through core design features 15 % enriched TRISO fuel<br />

and operational reactivity control via Y-shaped control<br />

rods. Energy conversion is a 3-loop (FLiBe, NaBF 4 ,<br />

supercritical CO 2 ) design so as to avail pro duction of<br />

electricity, hydrogen and energy storage, juxtaposed<br />

against the Czech national energy portfolio. Common<br />

to many national nuclear conceptual design engineering<br />

studies (here at nuclear R&D centre, Rez), while<br />

development details may be ongoing, a path toward<br />

commercialized deployment is unknown.<br />

2) MoveLuX (Toshiba, Japan) – is a sodium heat-pipe<br />

cooled and calcium hydride moderated, natural<br />

convection (air-based primary circuit) driven MMR<br />

with thermal/electrical power output, targeted at<br />

10 MWt/3-4 MWe. The core design uses uranium<br />

silicide (U 3 Si 2 ) fuel housed in hexagonal “cans” with<br />

lithium expansion system reactivity control. With a<br />

sodium heat pipe based higher temperature conversion<br />

system coupled to helium gas, electricity and hydrogen<br />

production are possible, as well as a fuel cycle adapted<br />

to the national fuel cycle practice. This MMR concept is<br />

a Toshiba internal conceptual design study.<br />

3) U-Battery (Urenco, UK) – is a high-temperature, helium<br />

gas-cooled, graphite-moderated MMR with targeted<br />

thermal/electrical output, 10 MWt/4 MWe. The core<br />

design uses TRISO fuel, enriched up to 20 %, in<br />

hexagonal blocks with control rods, fixed burnable<br />

poisons and shut-down absorber spheres. A 5-year full<br />

power year and 30-year design life are targeted. Energy<br />

conversion is via indirect secondary nitrogen circuit<br />

with applications both <strong>for</strong> heat applications or closed<br />

gas-turbine technology (no combustion stage).<br />

Regulatory approval of its detailed design and<br />

commercialization partners have been announced by<br />

its developer, URENCO – UK.<br />

Feature<br />

Small Modular Reactor Safety-in-Design and Perspectives ı Akira Tokuhiro, Chireuding Zeliang and Yi Mi

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

4) AURORA – (Oklo, USA) – with a targeted thermal/<br />

electric power output, 4 MWt/1.5 MWe, this compact,<br />

liquid-metal cooled fast reactor MMR using metal fuel,<br />

a 20-year refueling cyle, Oklo has applied <strong>for</strong> a USNRC<br />

combined license application. The plant features low<br />

power output, low power density and low decay heat<br />

output, and correspondingly has low fuel burnup, small<br />

fuel inventory, simplicity in energy removal by inherent<br />

and passive means, and overall takes advantage of<br />

thermal capacity via use of higher con ductivity material<br />

selection. Oklo has an existing agreement to access<br />

the Idaho National Lab site and some aspects of their<br />

technology know-how under a partnership agreement.<br />

5) eVinci Micro Reactor (Westinghouse, USA) – this<br />

conceptual design MMR with a targeted thermal/<br />

electrical power output, 7-12 MWt/2-3.5 MWe, uses<br />

(sodium) heat pipes and metal hydride moderator in a<br />

stand-alone, transportable reactor and energy conversion<br />

system unit. Instrumentation and controls are<br />

provided via a separate, integrated (second) unit. The<br />

core is based on TRISO or similarly encapsulated fuel,<br />

in a monolithic core with reactivity control realized via<br />

ex-core (moving) control drums. Onsite refueling or<br />

whole reactor replacement are envisioned. Energy<br />

conversion is via open-air Brayton and single shaft gas<br />

turbomachinery. The core is designed with negative<br />

reactivity, and decay heat removal is via intended<br />

conduction and natural convective heat dissipation to<br />

air. The design integrates many elements and simplifications<br />

based on lessons learned by Westinghouse in<br />

overall plant “island” design. The design concept is<br />

under Vendor Design Review, Canadian <strong>Nuclear</strong> Safety<br />

Commission (CNSC), and preliminary discussions with<br />

the USNRC.<br />

6) MMR (Ultra Safe <strong>Nuclear</strong>, USA) – this MMR with a<br />

( Canadian) national laboratory site partnership<br />

permit, has a targeted thermal/electrical power ouput,<br />

15 MWt/greater than 5MWe. This MMR is a hightemperature,<br />

(helium) gas-cooled, graphite- moderated,<br />

solar salt energy stored integral design. The core will<br />

use TRISO <strong>for</strong> fully ceramic micro-encapsulated (FCM)<br />

fuel pellets, HALEU enriched to just under 20 %, in<br />

hexagonal blocks with control rods. Its inherent core<br />

negative temperature feedback and low power density,<br />

dissipates heat radiatively and via natural convection.<br />

Energy conversion is via a 3-loop system with a molten<br />

salt intermediate (heat exchanger) loop that also stores<br />

thermal energy. This loop connected to a steam<br />

generator unit. The concept, under Global First <strong>Power</strong>,<br />

has submitted a license to prepare site initial application<br />

at CNL Chalk River site, and with the CNSC.<br />

various designs are most clearly revealed in the thermalhydraulic<br />

design that minimize and/or eliminate potential<br />

initiating events may be linked to DBA and certainly BDBA<br />

scenarios. In the latter case, the DBA/BDBA can then be<br />

claimed as impossible. Reflection of this approach then<br />

begs the question of prudent integration of the following<br />

practices: probabilistic risk assessment (PRA), system<br />

analysis ( RELAP and similar), accident analysis (MELCOR<br />

and similar) and dispersion analysis. The work by Williams<br />

et al. [34] describes the safety-in-design, including <strong>for</strong>emost,<br />

defense-in-depth and putting into (design) practice,<br />

the INSAG-10 explicit levels.<br />

2.3 Gas-cooled, graphite-moderated<br />

Large scale gas-cooled, often graphite-moderated reactors<br />

have a history as long as water-cooled, thermal spectrum<br />

reactors. As such, there have been generational reactor<br />

concepts paralleling that of LWRs. Much of the<br />

generational development can be traced to the 1950s to<br />

1970s, and is associated with the prismatic (block) type<br />

Magnox and AGR in the UK [41, 42]. The pre-commercial,<br />

experimental Dragon reactor introduced the TRISO<br />

(tristructral- isotropic) fuel type. Soon thereafter, the<br />

German constructed and operated the AVR (Arbeitsgemeinschaft<br />

Versuchsreaktor), with a pebble bed fuel and<br />

moderator (spheres) core configuration, demonstrated<br />

high- termperature operation using gas as coolant. This<br />

reactor concept is often attributed to Daniels and Schulten,<br />

and following the AVR saw incremental developments via<br />

the following: German THTR-300, the Japanese High<br />

| Figure 1<br />

U-Battery Design (Source: www.u-battery.com/design-and-technology).<br />


2.2 Water-cooled, moderated, thermal spectrum<br />

designs<br />

Due to the large number of light water-cooled, thermal<br />

spectrum reactor designs in the history of nuclear energy,<br />

SMRs based on the similar light water moderation,<br />

reflection and cooling concepts comprise the largest<br />

grouping of SMR concepts and designs at present. In fact,<br />

one of the most complete, if not the only completed design<br />

is that by NuScale <strong>Power</strong>. Not surprisingly, many aspects of<br />

the design, engineering, system design and overall, design<br />

methodology are proprietary. That said, based on a survey<br />

of various SMR designs of integral Pressurized Water<br />

Reactor type (iPWR) by Zeliang, Mi and co-workers [32], if<br />

the selected core design is conventional (primarily to<br />

reduce overall cost), but smaller, then differences in<br />

| Figure 2<br />

The Micro Modular Reactor (MMR) system (Source: www.usnc.com/mmr-energy-system/).<br />

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Small Modular Reactor Safety-in-Design and Perspectives ı Akira Tokuhiro, Chireuding Zeliang and Yi Mi

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


| Figure 3<br />

Westinghouse eVinci Micro Reactor<br />

(Source: www.westinghousenuclear.com/new-plants/evinci-micro-reactor).<br />

Temperature Test Reactor (HTTR) and Chinese High<br />

Temperature Reactor, HTR-10. X-Energy’s Xe-100 is the<br />

current pebble-bed, high temperature, gas-cooled nuclear<br />

reactor (SMR) design, using TRISO fuel and with targeted<br />

output at 200 MWth/76 MWe. Consistent with many light<br />

water based SMR designs, the current day gas-cooled,<br />

graphite based concepts feature active or passive safety<br />

features.<br />

2.4 Unique Reactor Designs<br />

There are and can be other unique types of SMRs and<br />

MMRs designs and concepts, differing in selection of fuel<br />

type, fuel <strong>for</strong>m (solid vs. liquid), neutron energy spectrum,<br />

the combination of coolant, moderator and reflector,<br />

thermal/electrical output, safety-in-design and deployment<br />

strategies, including aspects of modularity, manufactureability,<br />

cost savings per advance manu facturing<br />

methods, and “add-on” benefits such as medical isotope,<br />

hydrogen and district heating production. It may be<br />

reasonable to say that, assuming that there is ( sovereign)<br />

regulatory review with inclusion of public consultation of<br />

any particular SMR design, aspects of technical innovation<br />

and interest, has to prevail against public sentiment and<br />

skepticism. Thus, innovative concepts rarely have a chance,<br />

even in demonstration, and in today’s social media driven,<br />

multi-national climate, consensus acceptance may be<br />

needed <strong>for</strong> certain. In other words, new technology<br />

solutions have to overcome a daily battle of disin<strong>for</strong>mation<br />

and misin<strong>for</strong>mation to garner and secure sustainable<br />

investments and developments. In other words, “the odds<br />

are not very good, even if the technology (the goods) are<br />

very innovative (not odd)”.<br />

2.5 Molten salt-fueled and cooled,<br />

and fast spectrum, liquid metal designs<br />

As noted, finishing the SMR design and submitting this <strong>for</strong><br />

regulatory review and approval, as well as commitment to<br />

construction via sufficient and satisfactory investments,<br />

are the most important in current SMR ef<strong>for</strong>ts. These<br />

linked objectives also apply to novel SMR/MMR concepts<br />

based on molten-salt fueled and cooled concepts as well as<br />

fast spectrum concepts. Historically and technically, fast<br />

spectrum concepts are often associated with liquid metal<br />

(sodium, lead, eutectic alloys, etc.) thermal-hydraulic<br />

system designs. Most notably, large thermal diffusivity<br />

(and conductivity, relative to water) and selection of<br />

materials with small neutron cross section, provide design<br />

advantages in fast spectrum concepts. A succinct summary<br />

of the sodium-cooled fast reactor is contained in [43]. The<br />

IAEA “2020 booklet” provides technical specification of<br />

the Terrestrial Energy’s [39] and Kairos <strong>Power</strong>’s (fluoride<br />

salt-cooled, high temperature, pebble bed), [40] designs,<br />

as well as the fast spectrum designs of the ARC-<br />

100 (sodium- cooled) and Oklo (MMR, HALEU fuel,<br />

supercritical CO 2 with heat pipe) concepts. Additional<br />

in<strong>for</strong>mation of technical interest can be found via ongoing<br />

regulatory review processes (examples: US, Canada) and<br />

open access publications and news releases. Of importance,<br />

relative to and in contrast to thermal spectrum SMR/<br />

MMRs with safety-in-design, is the inherently passive<br />

safety system feature (including reactivity control) corresponding<br />

to a defense-in-depth approach, that provides<br />

competitive, if not advantageous benefit, in the eyes of the<br />

stakeholders. Because these reactor concepts are or can be<br />

significantly different than thermal spectrum, water-based<br />

SMR/MMR designs (example, flowing in-solution liquid<br />

fuel and coolant), they provide important regulatory<br />

opportunity to confirm technology “neutrality” when that<br />

objective is sought.<br />

There are 11 fast spectrum SMR concepts noted in the<br />

IAEA – 2020 book. Of these, the Siberian Chemical<br />

Combine’s, BREST-OD-300, with declared thermal and<br />

electrical power output, 700 MWt/300 MWe, recently<br />

received license (from Rostechnadzor) to be constructed<br />

in Seversk. This, a lead (Pb-cooled and moderated, pool<br />

type fast reactor, is both a test and demonstration plant. It<br />

is thus an evolutionary design similar in design to French<br />

and Japanese one-off SFR designs (Super Phenix, Joyo,<br />

Monju), but incorporating lessons learned using lead and<br />

lead-bismuth within the Russian Federation. The core<br />

consists of mixed uranium-plutonium nitride fuel,<br />

enriched up to 14.5 %, in hexagonal configuration with<br />

chromium ferritic-martensitic steel cladding and capability<br />

<strong>for</strong> fuel breeding. Reactivity control is via shim and automatic<br />

control roads, while the 2-loop energy conversion<br />

system features a lead to water steam generator system.<br />

The emergency core cooling system is passive, and consists<br />

of pipes immersed directly into the primary system, thus<br />

serving as a natural circulation driven lead-to-air heat<br />

exchanger. Completion of construction is scheduled to be<br />

as early as 2026.<br />

It is worth noting that in terms of safety-in-design of<br />

liquid-metal cooled fast reactors, the key safety feature is a<br />

prompt, negative temperature feedback from Doppler<br />

broadening of the cross section. In simple terms, because<br />

of the combination of higher fuel enrichment (relative to<br />

water-cooled reactors), liquid metal as coolant and<br />

subsequent compactness of the overall core design, the<br />

power density of a fast reactor is larger than water-cooled<br />

reactors. Thus, the probability of an initiating event<br />

developing into an energetic event has to be considered.<br />

The safety-in-design of the EBR-II test/demonstration<br />

plant considered many of these aspects and demonstrated<br />

its inherent safety. In brief, historically documented<br />

( accident) phenomena specifically <strong>for</strong> sodium-cooled<br />

designs include the following: transient overpower, lossof-flow,<br />

fuel- vapor explosion, sodium vapor explosion,<br />

containment response under short and sustained loads.<br />

For specific liquid metal cooled, SMR-scale fast spectrum<br />

designs, these specific issues have to be addressed.<br />

It remains to be seen how the ARC-100 SFR will develop<br />

as a scaled-down, updated version of EBR-II [44], with<br />

some of the original EBR-II lead principals. The ARC-100 is<br />

a <strong>for</strong>ced circulation SFR, thermally projected to be<br />

286 MWt/100 MWe, and featuring U-Zr metallic fuel,<br />

enriched on average to 13.1 %, such that it has a 20-year<br />

refueling service life. Beyond the primary circuit, it<br />

features a 2-loop IHX to SG design, supported by four<br />

submersed EM pumps. The SG is a vertically oriented,<br />

helical coil, single-walled, counter-flow sodium-to-water,<br />

shell-in-tube design. Reactivity control is via a redundant<br />

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system of 6 control rods (3 x 2). Besides the core, many of<br />

the major energy conversion system components are<br />

integrated into the reactor vessel and defining building.<br />

The ARC-100 is undergoing CNSC Vendor Design Review<br />

and has Provincial support from New Brunswick ( Canada).<br />

Generational knowledge preservation and transfer, as well<br />

as work<strong>for</strong>ce capability to understand the SFR remains to<br />

be seen.<br />

Finally, we would be remiss if the long-standing promise<br />

of fast reactors as part of national energy self-sufficiency<br />

strategy via closing of the nuclear fuel cycle, is not noted.<br />

Un<strong>for</strong>tunately, no nuclear nation today completely<br />

practices a fully closed (commercial) nuclear fuel cycle<br />

and thus, with fast reactors of a SMR “kind”, we have to<br />

again maintain a sensible view to technology readiness of<br />

fuel reprocessing aspects <strong>for</strong> those fast SMR concepts that<br />

use existing supplies of spent fuel. Except possibly in China<br />

and the Russian Federation, openly competitive global<br />

markets have eroded the promise of fast reactors and<br />

closed fuel cycle.<br />

3 Lesson learned, evolution of<br />

safety-in-design, getting to the end<br />

One can look at the 70+-year history of nuclear power<br />

generation of electricity, and relative to other public use/<br />

acceptance of other risk-inherent technologies such<br />

as the automobile and travel via commercial airlines<br />

(approximately 100 years), begin to understand the<br />

development of social license/public acceptance of<br />

technologies. Once could state that un<strong>for</strong>tunately, nuclear<br />

power developed alongside environmental consciousness<br />

and a spectrum of “anti” movements that continue to this<br />

day. This paper is not intended to argue rightful acceptance<br />

of nuclear power. However, not preserving the options<br />

presented by nuclear generated electricity would be<br />

testimony to lack of <strong>for</strong>esight in the world we live in today,<br />

with the issues and challenges that we have.<br />

The ongoing “nuclear renaissance” of recent years can<br />

be summarized in terms of the following trends: 1)<br />

conceptual designs followed by various states of<br />

engineering design development of many types of SMRs<br />

and MMRs, 2) a broad discussion of the socio- technological<br />

importance of addressing (the emerging, negative impacts<br />

of) climate change, and thus, transitioning away from a<br />

carbon-based (fossil fueled) to low carbon or net zero<br />

carbon economies of scale using nuclear energy, and 3) unbeknownst<br />

to many but integration of lessons learned,<br />

evolution in safety-in-design thinking, and advancements<br />

in modeling and simulation (using high per<strong>for</strong>mance<br />

computing) <strong>for</strong> advanced reactor designs. Recent<br />

advancements in accident tolerant fuels, and advanced<br />

manufacturing are noted but perhaps years away from<br />

being inherent in SMR/MMR design.<br />

4 Emerging drivers in SMR and<br />

advanced reactor concept design<br />

The ongoing global interest and enthusiasm <strong>for</strong> SMR/<br />

MMR has generated many concepts but equally revealed<br />

uncoordinated global gaps, including regulatory review of<br />

the safety-in-design of various concepts. This is to be<br />

expected, given that regulatory mandate is at the national<br />

level. That said, there are a few bi-/tri-lateral collaboration<br />

agreements to share regulatory practices. It remains to<br />

be seen whether such collaborations will facilitate review<br />

and thus reduce the overall time to realizing any<br />

particular SMR/MMR concept. We further note that global<br />

institutions, such as the IAEA, WNA, OECD-NEA, WANO<br />

| Figure 4<br />

Conceptual sketch of weighting factor assignment.<br />

and related promote common understanding – here with<br />

respect to safety-in-design of SMRs/MMRs and other<br />

advanced reactor concepts. The authors herein describe<br />

emerging drivers or influences, based on many lessons<br />

learned in reactor concepts and designs. We offer this<br />

account since, design methods and approaches often<br />

remain proprietary and as such, not openly discussed. We<br />

thus offer <strong>for</strong> contemplation and discussion, high-level<br />

aspects of safety-in-design of SMRs.<br />

Figure 4 first shows a qualitative “high, medium or<br />

low” weighting in importance versus the INSAG-10 levels<br />

(1 to 5), meant to reflect historial perspective on defencein-<br />

depth. The figure compares conventional reactors<br />

( larger plants) versus SMRs currently proposed. We note<br />

that the weigthing <strong>for</strong> convential reactors may sensibly<br />

decrease incremental manner if level “1, 4, 5”, <strong>for</strong> example,<br />

loosely correspond to AOOs, DBA an BDBA respectively.<br />

That is, convential reactors have largely been designed so<br />

that safety systems can respond to and counter consequences<br />

of the postulated DBA. However, history has<br />

taught us that human operational error can generate<br />

BDBA-type situations; that is, leading to core meltdown<br />

(degradation) and (unintended) release of radioactivity<br />

beyond the plant boundary. Thus, <strong>for</strong> older generation<br />

reactor designs (Generation II), one could imagine a<br />

higher weighting <strong>for</strong> levels 1-to-3, relative to levels 4-to-5<br />

event. Since, the authors anticipate arguments under such<br />

qualitative perspectives, an uni<strong>for</strong>m, medium weighting<br />

across levels, 1-to-5, is also shown. It is conceivable that a<br />

particular, recent design (Generation III, III+) could<br />

feature uni<strong>for</strong>m weighting as depicted.<br />

In contrast, the designs of current SMRs are generally<br />

expected to reflect generational improvements in safety- indesign,<br />

overall. Thus, at minimum, the SMR may feature<br />

inherent, passive safety system/s in its design, and thus<br />

reflect a safety-in-design philosophy, that may emphasize<br />

at least “M” weighting <strong>for</strong> unlikely, level “4 or 5” scenarios.<br />

In so doing, the design eliminates the need <strong>for</strong> immediate<br />

(human) emergency response. This latter philosophy may<br />

not always be apparent by studying the design itself, but<br />

depicted through an integration of a number of safety- indesign<br />

aspects. In reality and with operational excellence<br />

taken into consideration, the relationship may be<br />

something similar to the (non-linear) dotted trend with<br />

high imporance placed on both low and higher level<br />

scenarios. Any difference in magnitude or slope comparing<br />

conventional reactors to SMRs, thus reflects historical<br />


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Small Modular Reactor Safety-in-Design and Perspectives ı Akira Tokuhiro, Chireuding Zeliang and Yi Mi

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DiD<br />

Level<br />

SMR target<br />

frequency (/yr)*<br />

No. Generic eliminated scenarios Contributing innovative features<br />

1. Large Break Loss of Coolant Accidents (LB-LOCAs) Integrated Reactor Cooling System<br />

2. Elimination of control rod ejection/injection accidents Integrated Control Rod Drive Mechanisms (CRDMs)<br />

3. Exclusion of inadvertent reactivity insertion as a result of boron dilution Eliminated liquid boron reactivity control system<br />

4. Elimination of loss of flow accidents and failures/scenarios related to<br />

reactor coolant pumps<br />

Naturally circulated primary system<br />

5. Elimination of the need <strong>for</strong> external power under accident conditions Fail-safe passive safety features on loss of power<br />

| Table 2<br />

SMR design features that challenge conventional safety analysis.<br />

Design characteristics<br />

Integral reactor coolant system (RCS)-<br />

design-reduced accident initiators<br />

Attributes<br />

Level 1 < 10 -2 Initiating event frequency<br />

Level 2 < 10 -5 Failure detection capability and control action<br />

(automatic or manual)<br />

Level 3 < 10 -8 Core damage frequency (CDF)<br />

Facilitating factors in (SMR) passive safety systems (PSSs) start-up/operation<br />

Minimizes accident initiators, thus consider use of PSS.<br />

Results in a simplified design<br />

Lower core power capacity Less (magnitude) decay heat to be removed 30)<br />

PRA<br />

Levels<br />

Level 1<br />

Level 4 < 10 -10 Conditional containment failure probability Level 2<br />

Level 5 < 10 -12 Large early release frequency (LERF) Level 3<br />

| Table 1<br />

Relationship among DiD, PRA, existing requirements and expectations. *small values can be argued, conservatively<br />

Current regulatory<br />

requirements (/yr)<br />

< 1 x 10 -5 and < 1 x 10 -4<br />

(depending on regulator)<br />

< 0.1<br />

(depending on regulator)<br />

< 1 x 10 -6<br />

(depending on regulator)<br />

Larger surface to volume ratio<br />

Larger primary coolant inventory<br />

per MW(th)<br />

Smaller reactor core power density<br />

Large secondary coolant inventory,<br />

e.g., NuScale reactor pool<br />

Taller and broader reactor pressure<br />

vessel or vessel containing core<br />

Facilitates decay heat removal due to large surface area,<br />

particularly <strong>for</strong> single phase flow<br />

Larger heat sink <strong>for</strong> natural circulation; larger buoyancy-driven<br />

flows/regioins; reduces requirements <strong>for</strong> heat removal systems 31)<br />

Larger thermal-hydraulics margins; favourable in long term decay<br />

heat removal, in particular via PSSs<br />

Facilitates passive decay heat removal and<br />

containment cooling 10)<br />

Facilitates decay heat removal via natural circulation,<br />

i.e., higher elevation difference between heat source and sink 30)<br />

| Table 3<br />

SMR design features that challenge conventional safety analysis.<br />

lessons learned and competing philosophies in safety- indesign<br />

of nuclear reactors.<br />

Continuing, Table1 below provides a semi-quantitative<br />

equivalent to Figure 4 but compares INSAG-10 levels,<br />

against the possible SMR target frequencies (a design<br />

merit), short descriptors of the corresponding attributes of<br />

an event or accident, the commonly noted PRA levels, and<br />

the currently known regulatory values <strong>for</strong> existing plants.<br />

This table is qualitative and simply contrasts different<br />

perspectives that may be used by a SMR designer. We<br />

recognize that small frequency values, say less than 1E-08,<br />

may not hold regulatory meaning and as such, higher<br />

frequencies <strong>for</strong> levels 1-5 may apply, depending on the<br />

practicality of such values in regulatory review of<br />

submitted SMR/MMR designs and concepts. Finally, as a<br />

measure of confidence in its design, a vendor may assume<br />

a probability 3 orders of magnitude smaller at each level,<br />

except at level 4-and-5.<br />

Table 2 provides five representative, generic events<br />

<strong>for</strong> which design features and/or design concepts of<br />

recent SMRs (also MMRs), have either greately reduced or<br />

eliminated all together the likelihood of such vulnerabilities,<br />

most often associated with conventional reactor<br />

designs. Here again, through gradual advancements in<br />

conventional reactor safety-in-design, further facilated by<br />

ongoing development in SMRs, safety-in-design and<br />

defence- in-depth have both been embodied in various<br />

SMR designs. The rightmost column gives an example of<br />

the SMR design feature that eliminated the generic<br />

scenarios.<br />

Finally, Table 3 representative design characteristics<br />

or features observed in recent iPWR-type SMRs (left<br />

column), relative to their phenomenolgical impact in<br />

assuring energy removal under many severe accident<br />

scenarios and design vulnerabilties associated with<br />

conventionl reactor designs. Further, <strong>for</strong> a given SMR design<br />

encompassing a mulitple number of design characteristics<br />

as above, operator intervention is greatly reduced or eliminated<br />

<strong>for</strong> substantial durations of time, starting from the<br />

initiating event and possibly linked to an additional<br />

sequence of unlikely events. In other words, current SMR<br />

designs anticipate BDBA and catastrophic, external events.<br />

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5 Uphill costs and getting to the end<br />

It is no secret there are major milestones on the path to<br />

realizing any new commercial nuclear power plant. Some<br />

major milestones that come to mind are first criticality and<br />

connection to the electricity grid. New conventional builds<br />

have however become too expensive, relative to other<br />

large infrastructure projects and public spending that<br />

address regional to national priorities. As ramification of<br />

the Fukushima Daiichi earthquake-tsunami-nuclear plant<br />

accident, and examples of cost overruns and delays associated<br />

with large nuclear plant projects persist, “opportunist”<br />

have taken sides – to either support or not support<br />

nuclear energy as a valued energy source option. It is well<br />

known that the merits of nuclear power (as zero to low<br />

carbon) in addressing the negative impacts of climate<br />

change, continue to be argued in public and social media<br />

spaces. Pragmatism regarding public infrastructure need<br />

can become easily mired and disconnected to those elected<br />

and engaged in media. If the authors may inject opinion,<br />

nuclear energy is an energy technology that we have today<br />

and it provides, at minimum, the time needed <strong>for</strong> society to<br />

reach consensus via change in mindsets, values and beliefs.<br />

This lead author is of the opinion that addressing climate<br />

change is just as much a matter of change needed in how<br />

we live and consume. Energy consumption and its sources<br />

are very much part of the anthropocene.<br />

While various perspective on developments in SMRs/<br />

MMRs can be taken, the authors’ position here is that<br />

getting to the “end” may be the most important.<br />

6 Conclusion<br />

Development of various Small- and Micro-Modular<br />

Reactor concepts, regardless of its point of origin depends<br />

on alignment of both timely and prudent engineering and<br />

design ef<strong>for</strong>ts, sustained financial backing during this<br />

ef<strong>for</strong>t and, public and/or private stakeholder investments<br />

so that a first-of-a-kind reactor (FOAK) is constructed on<br />

time and at cost, post timely regulatory safety-in-design<br />

approval. Beyond the FOAK plant, expectations are such<br />

that sustained investments and commitments, parallel<br />

reduction in cost with each additional unit constructed in<br />

modular manner.<br />

Here the authors have elaborated on a holistic safety- indesign<br />

perspectives wherein technical features make<br />

design and beyond design basis accidents nearly impossible<br />

(or eliminated), and even under improbable initiating<br />

events, decay heat removal is passive such that it does not<br />

require operator intervention <strong>for</strong> a defined length of time.<br />

The article also emphasized that completion of the design<br />

and (time) efficient regulatory review of the submitted<br />

design, are of tantamount importance with respect to the<br />

sustained investments, and can determine the fate of any<br />

given SMR/MMR design. It is clear that regional to national<br />

support of nuclear energy, an existing history of reactor<br />

design development, a skilled nuclear and energy sector<br />

work<strong>for</strong>ce, and an existing supply chain are increasingly<br />

expected conditions when considering new nuclear plants.<br />

Finally, early public engagement and confirmation of<br />

gradual public acceptance and social license (nominal<br />

acceptance of nuclear energy) must exist, as identified via<br />

fleeting social media plat<strong>for</strong>ms. This is the reality of the<br />

world that we live in today. Let us brave the future of<br />

nuclear energy.<br />

Acknowledgments<br />

The lead author thanks Ontario Tech University and its<br />

Faculty of Energy Systems and <strong>Nuclear</strong> Science. He also<br />

thanks contributions to recent research on SMRs from<br />

Chireuding Zeliang and Yi Mi. The lead author would<br />

like to thank partial support by the National Science,<br />

Engineering Research Council (of Canada), CREATE<br />

528176-2019, awarded to McMaster University with<br />

Ontario Tech University as partnering institution.<br />

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and Challenges”, Discussion paper DIS-16-04 (2016).<br />

[16] Ingersoll, D. T., “An overview of the safety case <strong>for</strong> small modular reactors”, ASME 2011 Small<br />

Modular Reactors Symposium, American Society of Mechanical Engineers (2011).<br />

[17] U.S. Code of Federal Regulations, “General Design Criteria <strong>for</strong> <strong>Nuclear</strong> <strong>Power</strong> Plants,”<br />

Introduction, 10 CFR 50 Appendix A, US NRC, (2015).<br />

[18] <strong>International</strong> Atomic Energy Agency, “Basic Safety Principles <strong>for</strong> <strong>Nuclear</strong> <strong>Power</strong> Plants”,<br />

INSAG-12, IAEA, Vienna (1999).<br />

[19] LaChance, J., et al. “Evaluation of the Applicability of Existing <strong>Nuclear</strong> <strong>Power</strong> Plant Regulatory<br />

Requirements in the US to Advanced Small Modular Reactors.” SAND2013-3683, Sandia<br />

National Laboratories, Albuquerque, NM (2013).<br />

[20] <strong>International</strong> Atomic Energy Agency, “Progress in Methodologies <strong>for</strong> the Assessment of Passive<br />

Safety System Reliability in Advanced Reactors”, TECDOC-1752, IAEA, Vienna (2014).<br />

[21] NuScale <strong>Power</strong>, LLC Submittal of, “Methodology <strong>for</strong> Establishing the Technical Basis <strong>for</strong> Plume<br />

Exposure Emergency Planning Zones at NuScale Small Modular Reactor Plant Sites”, Revision 1,<br />

TR-0915-17772, Corvallis, USA (2018).<br />

[22] Apostolakis, G., et al., “A proposed risk management regulatory framework”, NUREG-2150,<br />

US <strong>Nuclear</strong> Regulatory Commission, (2012).<br />

[23] Williams, C., W. J. Galyean, and K. B. Welter, “Integrating quantitative defense-in-depth<br />

metrics into new reactor designs”, <strong>Nuclear</strong> Engineering and Design, 330, 157-165 (2018).<br />

[24] Chierici, L., Fiorini, G.L., La Rovere, S. and Vestrucci, P., “The Evolution of Defense in Depth<br />

Approach: A Cross Sectorial Analysis. Open <strong>Journal</strong> of Safety Science and Technology, 6, 35-54<br />

(2016).<br />

[25] <strong>International</strong> Atomic Energy Agency, “A Framework <strong>for</strong> an Integrated Risk In<strong>for</strong>med Decision<br />

Making Process”, INSAG-25, IAEA, Vienna (2011).<br />

[26] <strong>International</strong> Atomic Energy Agency, “Safety related terms <strong>for</strong> advanced nuclear plants”,<br />

TECDOC-626, IAEA, Vienna, Austria (1991).<br />

[27] <strong>International</strong> Atomic Energy Agency, “Passive Safety Systems and Natural Circulation in Water<br />

Cooled <strong>Nuclear</strong> <strong>Power</strong> Plants”, TECDOC-1624, IAEA, Vienna, Austria (2009).<br />

[28] General Electric Company, “The ESBWR Plant General Design Description”, GE <strong>Nuclear</strong> Energy,<br />

NC, USA (2007).<br />

[29] Schulz, T.L. “Westinghouse AP1000 advanced passive plant.” <strong>Nuclear</strong> Engineering and Design<br />

236.14-16, 1547-1557 (2006).<br />

[30] <strong>International</strong> Atomic Energy Agency, “Design Features to Achieve Defence in Depth in Small and<br />

Medium Sized Reactors”, <strong>Nuclear</strong> Energy Series NP-T-2.2, IAEA, Vienna (2009).<br />

[31] Hidayatullah, H., et al., “Design and technology development <strong>for</strong> small modular reactors–Safety<br />

expectations, prospects and impediments of their deployment”, Progress in <strong>Nuclear</strong> Energy 79,<br />

127-135 (2015).<br />

[32] Zeliang, C., Mi, Y., Tokuhiro, A., Lu, L., and Rezvoi, A. (2020). Integral PWR-Type Small Modular<br />

Reactor Developmental Status, Design Characteristics and Passive Features: A Review. Energies<br />

(Basel), 13(11), 2898–. https://doi.org/10.3390/en13112898<br />

[33] IAEA –<strong>International</strong> Atomic Energy Agency, Advances in Small Modular Reactor Technology<br />

Developments (2020).<br />

[34] Williams, C., Galyean, W. J., & Welter, K. B. (2018). Integrating quantitative defense-in-depth<br />

metrics into new reactor designs. <strong>Nuclear</strong> Engineering and Design, 330(C), 157–165.<br />

[35] Kloosterman, J. (2018). Molten Salt Reactors and Thorium Energy, edited by Thomas J. Dolan<br />

[Review of Molten Salt Reactors and Thorium Energy, edited by Thomas J. Dolan]. Annals of<br />

<strong>Nuclear</strong> Energy, 117, 1–2. Elsevier Ltd. https://doi.org/10.1016/j.anucene.2018.02.017<br />


Feature<br />

Small Modular Reactor Safety-in-Design and Perspectives ı Akira Tokuhiro, Chireuding Zeliang and Yi Mi

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


[36] Zohuri, B.. Small Modular Reactors as Renewable Energy Sources . Cham, Switzerland: Springer,<br />

2019. Print.<br />

[37] Canadian <strong>Nuclear</strong> Safety Commission, Pre-licensing Vendor Design Review.<br />

http://nuclearsafety.gc.ca/eng/reactors/power-plants/pre-licensing-vendor-design-review/<br />

index.cfm<br />

[38] Irish, S., and LeBlanc, D. (2018). Driving change with IMSR: Terrestrial Energy’s integral molten<br />

salt reactor is redefining what a nuclear plant can do. <strong>Nuclear</strong> Engineering <strong>International</strong>,<br />

63(773), 20–.<br />

[39] Bland<strong>for</strong>d, E., Brumback, K., Fick, L., Gerardi, C., Haugh, B., Hillstrom, E., Zweibaum, N. (2020).<br />

Kairos power thermal hydraulics research and development. <strong>Nuclear</strong> Engineering and Design,<br />

364(C), 110636–.<br />

[40] Hussein, E. Emerging small modular nuclear power reactors: A critical review. Physics Open, 5,<br />

100038 (2020)<br />

[41] Wikipedia article on “Magnox”, as of March 29, 2021; https://en.wikipedia.org/wiki/Magnox<br />

[42] Wikipedia article on “Advanced Gas-cooled Reactor”, as of March 28, 2021;<br />

https://en.wikipedia.org/wiki/Advanced_Gas-cooled_Reactor<br />

[43] Wikipedia article on “sodium-cooled fast reactor, as of April 10, 2021;<br />

https://en.wikipedia.org/wiki/Sodium-cooled_fast_reactor#:~:text=A%20sodium%2Dcooled%20fast%20reactor,metal%2Dfueled%20integral%20fast%20reactor.<br />

[44] Wikipedia article on “Experimental breeder reactor II”, as of April 10, 2021;<br />

https://en.wikipedia.org/wiki/Experimental_Breeder_Reactor_II<br />

Authors<br />

Prof. Akira Tokuhiro<br />

Dean and Professor at the Faculty<br />

of Energy Systems and <strong>Nuclear</strong> Science<br />

Ontario Tech University, Ontario, Canada<br />

Akira.Tokuhiro@ontariotechu.ca<br />

Akira Tokuhiro is Dean and Professor at the Faculty of Energy Systems and <strong>Nuclear</strong><br />

Science at Ontario Tech University in Oshawa, Ontario, Canada. His primary R&D<br />

interests are in development of advanced reactor concepts, including small modular<br />

reactors. He joined Ontario Tech University from NuScale <strong>Power</strong>. He has nuclear and<br />

energy R&D experiences in Switzerland, Japan, USA and Canada.<br />

Yi Mi<br />

Master of Applied Science in <strong>Nuclear</strong> Engineering<br />

yi.mi@uoit.net<br />

Yi Mi is a young nuclear engineering professional with research experience in<br />

Probabilistic Risk Assessment (PRA) and Small Modular Reactor (SMR) Technology<br />

Development. He completed his Master of Applied Science degree in January 2020,<br />

in <strong>Nuclear</strong> Engineering, at Ontario Tech University His research was on SMRs,<br />

especially integral Pressurized Water Reactors (iPWRs). His focus was on safetyin-design<br />

methodology of small modular reactors (SMR). Specifically, he was<br />

integrating a number of tools and methods such as, system analysis and<br />

probabilistic risk analysis codes (LabVIEW and CAFTA), but including in the<br />

methodology, scaling analysis of iPWR type SMR with passive safety systems.<br />

Also, he studied the similarity and differences among different types of SMRs<br />

including iPWR, Steam Cycle-High Temperature Gas-Cooler Reactor (SC-HTGR),<br />

Fluoride-salt-cooled High Temperature reactor (FHR) and CO2-cooled micro modular<br />

reactor (MMR). Be<strong>for</strong>e OntarioTech, hec ompleted a Bachelor of Engineering in<br />

Chemical Engineering in Sichuan University.<br />

Chireuding Zeliang<br />

Junior Engineer/Analyst<br />

Kinectrics Inc., Toronto, Canada<br />

Chireuding Zeliang is a young nuclear engineering professional with research and<br />

work experience in Probabilistic Risk Assessment (PRA) and Small Modular Reactor<br />

(SMR) Technology Development. He currently works with Kinectrics Inc. as a Junior<br />

Engineer/Analyst in the areas of PRA as well as Design Modification of Safety and<br />

Supporting systems in CANDU nuclear plants. Prior to joining Kinectrics, Chireuding<br />

pursued his research career in PRA and SMR Technology Development from University<br />

of Ontario Institute of Technology under a 15 countries collaborative IAEA Coordinated<br />

Research Project on ‘Design and Per<strong>for</strong>mance Assessment of Passive Engineered<br />

Safety Features in Advanced SMRs’. He holds two (2) Master’s degree from<br />

University of Ontario Institute of Technology and Indian Institute of Technology<br />

Kanpur, and a Bachelor’s degree from North Eastern Regional Institute of Science<br />

and Technology, India.<br />

Feature<br />

Small Modular Reactor Safety-in-Design and Perspectives ı Akira Tokuhiro, Chireuding Zeliang and Yi Mi

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Did you know?<br />

<strong>Nuclear</strong> <strong>Power</strong> as Part of Sustainable Energy Policy –<br />

UNECE Working Group Report<br />

In the 2021 report “Application of the United Nations Framework<br />

Classification <strong>for</strong> Resources and the United Nations Resource<br />

Management System: Use of <strong>Nuclear</strong> Fuel Resources <strong>for</strong> Sustainable<br />

Development Entry Pathways” prepared by the Expert<br />

Group on Resource Management (EGRM) of the United Nations<br />

Economic Commission <strong>for</strong> Europe (UNECE) the role of nuclear<br />

energy is explored in the framework of the UN‘s 2030 Agenda<br />

<strong>for</strong> Sustainable Development. Key insights of this work among<br />

other are:<br />

p “<strong>Nuclear</strong> energy is an indispensable tool <strong>for</strong> achieving the<br />

global sustainable development agenda. It has a crucial role<br />

in decarbonizing the energy sector, as well as eliminating<br />

poverty, achieving zero hunger, providing clean water,<br />

af<strong>for</strong>dable energy, economic growth, and industry innovation.<br />

...”<br />

p “<strong>Nuclear</strong> energy entry pathways <strong>for</strong> newcomer countries align<br />

with the 2030 Agenda <strong>for</strong> Sustainable Development. <strong>Nuclear</strong><br />

energy programmes, based on the IAEA‘s Milestones<br />

Approach, support national energy needs, socio-economic,<br />

and environmental goals, and can help countries meet international<br />

climate commitments”<br />

p “Currently available nuclear reactor designs are based on<br />

mature and proven technologies that in some instances have<br />

been licensed to operate <strong>for</strong> 80 years. ... They provide reliable,<br />

af<strong>for</strong>dable and low-carbon electricity that will support a<br />

country in meeting its sustainable development goals.”<br />

The report states to meet “a need expressed by global decision<br />

makers to better understand the role nuclear energy may play in<br />

the energy transition”. It gives advice on how to foster and embed<br />

the entry into nuclear energy in a larger framework of policies<br />

and recommendations on how to facilitate the implementation of<br />

a nuclear energy programme. The “embedding” policies include<br />

policies <strong>for</strong> sustainable development and a low-carbon energy<br />

transition, energy market re<strong>for</strong>ms that support long term strategic<br />

investment, policies to improve energy security and resilience<br />

and an industrial development strategy. Typical policies aiming<br />

<strong>for</strong> a low carbon energy system that foster nuclear power are<br />

deep decarbonization or a net-zero carbon target, technologyneutral<br />

low-carbon energy portfolio standards, coal/fossil fuel<br />

phase- outs, increasing electrification of heat and transport,<br />

decarbonization and modernization of energy-intensive industries.<br />

Regarding the electricity market design the report calls<br />

among other to value energy reliability, resilience and the need<br />

<strong>for</strong> technologies providing secure, reliable and dispatchable<br />

generation to support the integration of variable renewables. It<br />

proposes as well to include non-power (socio-economic) benefits.<br />

The report makes mention of the assessment in a recent OECD-<br />

NEA report that <strong>for</strong> a generalized country the most cost-effective<br />

option to achieve a decarbonization target of 50 g CO 2 /kWh is a<br />

mix relying primarily on nuclear energy. Even in cases with ultralow-cost<br />

wind and solar PV an aggressive decarbonization target<br />

would require a share of 40 – 60 percent dispatchable low-carbon<br />

technologies such as nuclear.<br />

When eventually a decision in favour of nuclear power has been<br />

reached, supporting measures <strong>for</strong> implementation according to<br />

the report are international cooperation, regulatory harmonization,<br />

the development of indigenous capabilities, the delivery of<br />

projects on time and on budget, the proactive engagement of<br />

stakeholders and diversity in the nuclear sector with regard to<br />

gender balance. The report also assesses the issues of sustainable<br />

resource management, socioeconomic and environmental<br />

factors, the nuclear fuel cycle, nuclear waste management<br />

and disposal as well as nuclear technologies and innovation<br />

perspectives among other.<br />


17<br />

200<br />

150<br />

100<br />

Projected Costs of Energy Technologies by<br />

Country (2020) in USD/MWh (Median LCOE)<br />

(Data: IEA)<br />

External Costs of Health effects <strong>for</strong><br />

14 Technologies as of 2025,<br />

NEEDS study 2009<br />

<br />

Lignite<br />

Lignite post-comb CCS<br />

Lignite oxy-fuel CCS<br />

Coal<br />

Coal post-comb CCS<br />

Coal oxy-fuel CCS<br />

CCGT<br />

in Euro cent/kWh<br />

Source:<br />

Application of the United<br />

Nations Framework<br />

Classification <strong>for</strong><br />

Resources and the<br />

United Nations Resource<br />

Management System:<br />

Use of <strong>Nuclear</strong> Fuel<br />

Resources <strong>for</strong> Sustainable<br />

Development – Entry<br />

Pathways, Expert<br />

Group on Resource<br />

Management (EGRM),<br />

United Nations Economic<br />

Commission <strong>for</strong> Europe<br />

(UNECE), Geneva 2021<br />

CCGT CCS<br />

50<br />

0<br />

India United States China Europe Japan<br />

Coal Gas<br />

(CCGT)<br />

<strong>Nuclear</strong> Onshore<br />

wind<br />

(> = 1MW)<br />

Offshore<br />

wind<br />

Solar PV<br />

(utility scale)<br />

Wind<br />

PV<br />

Solar Thermal<br />

Biomass<br />

Ocean<br />

<strong>Nuclear</strong><br />

0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6<br />

For further details<br />

please contact:<br />

Nicolas Wendler<br />

KernD<br />

Robert-Koch-Platz 4<br />

10115 Berlin<br />

Germany<br />

E-mail: presse@<br />

KernD.de<br />

www.KernD.de<br />

Did you know?

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

18<br />

The <strong>Nuclear</strong> Innovation Policy of Canada<br />


Q&A with the Ministry of Natural Resources Canada<br />

Canada pursues an ambitious climate policy and is strongly committed to nuclear innovation. Today Canada is a<br />

front runner in the development, design review and licensing of micro, small modular and advanced modular reactors.<br />

Natural Resources Canada (NRCan) supported this development with Canada’s SMR Roadmap process in 2018 and the<br />

SMR Action Plan which is expected to yield concrete results within this decade. Canadian nuclear innovation policy<br />

aims beyond decarbonization in Canada and the fulfillment of specific Canadian local energy needs. Part of the policy<br />

is to establish new nuclear technologies globally as part of climate solutions and become a prime supplier of such<br />

technologies. The Q&A below with the Ministry of Natural Resources Canada (NRCan) gives you insights on the<br />

Canadian nuclear policy, its consensual making, its goals and the current state of progress.<br />

About the SMR Action Plan<br />

Canada's Small Modular Reactor (SMR) Action Plan is<br />

Canada's plan <strong>for</strong> the development, demonstration and<br />

deployment of SMRs <strong>for</strong> multiple applications at home and<br />

abroad.<br />

SMRs are a promising new technology that could unlock a<br />

range of benefits: economic, geopolitical, social, and<br />

environmental. Canada’s SMR Action Plan brings together<br />

essential enabling partners, leveraging their strengths to<br />

lock-in these benefits and lead the world on SMRs.<br />

The Action Plan is the result of a pan-Canadian ef<strong>for</strong>t<br />

bringing together key enablers from across Canada, which<br />

are called “Team Canada” – the federal government,<br />

provinces and territories, Indigenous Peoples and communities,<br />

power utilities, industry, innovators, laboratories,<br />

academia, and civil society.<br />

Each of these key enablers has contributed a chapter to the<br />

Action Plan, describing a concrete set of actions they<br />

are taking to seize the SMR opportunity <strong>for</strong> Canada.<br />

Collectively, these chapters demonstrate the breadth of<br />

engagement on SMRs across the country and outline the<br />

depth of progress and ongoing ef<strong>for</strong>ts.<br />

Canada has a long and impressive tradition in the<br />

use of nuclear energy and nuclear technologies.<br />

The CANDU reactors have been successfully<br />

developed and introduced; the only commercial<br />

non-LWR technology with worldwide recognition.<br />

From your point of view, what are the Canadian´s<br />

Government expectations <strong>for</strong> the nuclear sector?<br />

Small modular reactors (SMRs) are a potential gamechanging<br />

technology that can help Canada meet and<br />

exceed its emissions targets while creating economic<br />

opportunities in a post-pandemic world.<br />

<strong>Nuclear</strong> energy plays an important role in Canada’s<br />

current energy mix, accounting <strong>for</strong> 15 percent of our<br />

electricity supply, including approximately 60 percent of<br />

our supply in Ontario and approximately 40 percent in<br />

New Brunswick. The sector also contributes approximately<br />

$17 billion a year to Canada’s gross domestic product, and<br />

accounts <strong>for</strong> approximately 76,000 jobs across the country,<br />

including over 200 small- and medium-sized enterprises.<br />

SMRs are an opportunity <strong>for</strong> Canada to produce nonemitting<br />

power where it’s needed. The Government of<br />

Canada recognizes that it has a role to play in supporting<br />

this emerging innovative sub-sector, and in enabling<br />

Canada to seize these benefits.<br />

With the “SMR Road Map” and the recent “SMR<br />

Action Plan” from December 2020 Canada places<br />

itself on the <strong>for</strong>efront of this technology. What are<br />

the primary objectives of this SMR policy?<br />

SMRs have the potential to support Canada in its<br />

goals to reach net-zero by 2050 by accelerating electricity<br />

decarbonization, moving Canadians off coal and diesel,<br />

and driving deep indus trial decarbonization, all while<br />

creating jobs <strong>for</strong> Canadians.<br />

Over 100 organizations have submitted chapters to<br />

the Action Plan. For more in<strong>for</strong>mation on our SMR<br />

Roadmap and Action Plan, see the ‘About’ section here:<br />

https://smractionplan.ca/<br />

What are the main advantages and prospective<br />

applications of this technology?<br />

SMRs are nuclear reactors that are:<br />

p smaller, with a lower up-front capital investment than<br />

traditional nuclear power plants;<br />

p simpler, involving modular designs and a fleet-based<br />

approach to control cost and shorten project schedules;<br />

and<br />

p cheaper to compete with alternatives, enabling new<br />

applications such as hybrid nuclear-renewable energy<br />

systems.<br />

Many SMR designs also offer enhancements to improve<br />

safety, per<strong>for</strong>mance, and prevention of accidents.<br />

In Canada, SMRs have three major areas of application:<br />

p on-grid power generation, especially in provinces<br />

phasing out coal in the near future. Utilities want to<br />

replace end-of-life coal plants with non-emitting baseload<br />

plants of similar size;<br />

p on- and off-grid combined heat and power <strong>for</strong> heavy<br />

industry, such as cement producers; and<br />

p off-grid power, district heating, and desalination in<br />

remote communities. These currently rely almost<br />

exclusively on diesel fuel, which has various limi tations.<br />

Interview<br />

The <strong>Nuclear</strong> Innovation Policy of Canada ı Ministry of Natural Resources Canada

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

The “SMR Action Plan” assembles an impressively<br />

broad coalition of stakeholders from many<br />

segments of society. How was it possible to gain<br />

so much and diverse support <strong>for</strong> the Canadian<br />

SMR endeavor?<br />

Natural Resources Canada ( NRCan) recognizes the<br />

potential <strong>for</strong> this emerging area of nuclear innovation and<br />

understands the importance of diverse, strategic partnerships.<br />

That’s why, in 2018, NRCan convened Canada’s SMR<br />

Roadmap, a ten-month cross- country conversation on<br />

Canada’s SMR opportunity that brought together<br />

provincial and territorial governments, power utilities,<br />

industry and other interested stakeholders to chart a path<br />

<strong>for</strong>ward <strong>for</strong> this technology in Canada. The report made<br />

over 50 recommendations, which Canada’s SMR Action<br />

Plan responds to and builds on.<br />

The SMR Action Plan is the result of a pan-Canadian<br />

ef<strong>for</strong>t bringing together key enablers from across Canada,<br />

including the federal government, provinces and territories,<br />

Indigenous Peoples and communities, power utilities,<br />

industry, innovators, laboratories, academia, and civil<br />

society. Each of these key enablers contributed a chapter to<br />

the Action Plan, describing a concrete set of actions they<br />

are taking to seize the SMR opportunity <strong>for</strong> Canada.<br />

Collectively, these chapters demonstrate the breadth of<br />

engagement on SMRs across the country and outline the<br />

depth of progress and ongoing ef<strong>for</strong>ts.<br />

INTERVIEW 19<br />

Decarbonization is a global challenge, not a<br />

challenge <strong>for</strong> single countries or regions. Is the<br />

export and the sharing of know-how of Canadian<br />

nuclear technology to other countries part of the<br />

“SMR Action Plan”?<br />

The SMR Action Plan is Canada’s plan <strong>for</strong> the development,<br />

demonstration and deployment of SMRs <strong>for</strong> multiple<br />

applications at home and abroad. Over the past six<br />

decades, the Government of Canada has successfully<br />

established and maintained strategic bilateral and multilateral<br />

partnerships around the globe to advance shared<br />

nuclear energy priorities. With our own power reactor<br />

technology and full-spectrum nuclear capabilities, Canada<br />

belongs to an elite group of Tier 1 nuclear nations.<br />

With demonstrated leadership and expertise in nuclear<br />

science and technology, Canada is in a position to lead<br />

and contribute to international partnerships to support<br />

the development and deployment of SMRs across the<br />

globe.<br />

What is the timeline of SMR projects in Canada and<br />

which are the closest to realization?<br />

The Government of Canada understands the important<br />

role it has to play in advancing SMR technology in time <strong>for</strong><br />

Canada to be a world leader and to provide a non-emitting<br />

alternative <strong>for</strong> jurisdictions that must phase out conventional<br />

coal-fired power plants by 2030. The Government of<br />

Canada also recognizes the leadership of provincial and<br />

territorial governments and power utilities in SMR deployment,<br />

and plans to continue working together to make<br />

Canada a world leader in SMR technology.<br />

Several provinces that must phase out conventional<br />

coal-fired power plants are at a critical decision point <strong>for</strong><br />

new electricity sources, and the commercialization of<br />

SMRs could allow these provinces to achieve and lock in a<br />

decarbonized energy mix.<br />

The ongoing projects in Ontario to extend the life of the<br />

Darlington and Bruce nuclear plants have led to a rampedup<br />

nuclear supply chain, creating thousands of new jobs.<br />

| This map shows that all uranium comes from mines in Saskatchewan, but uranium processing,<br />

refining, conversion, fuel fabrication, research and waste management happens across Canada. <strong>Nuclear</strong><br />

power stations are located in Ontario and New Brunswick. (Source: Natural Resources Canada)<br />

As these projects end in the late 2020s and early 2030s,<br />

SMR projects could present an opportunity to sustain this<br />

capacity into the long term, as found through Canada’s<br />

SMR Roadmap. In other regions throughout the country,<br />

including Atlantic, Western and Northern Canada, SMRs<br />

are an opportunity to develop a new economic driver<br />

supporting good, middle-class jobs, and the Government<br />

of Canada supports ef<strong>for</strong>ts to enable all regions to benefit<br />

from Canada’s SMR oppor tunity.<br />

Through Canada’s SMR Action Plan, Sask<strong>Power</strong> identified<br />

that they are evaluating several potential low<br />

emissions pathways, including the deployment of nuclear<br />

power from SMRs in the 2032 – 2042 timeframe, with a<br />

view to limiting the deployment of new natural gas<br />

generation in the 2025 – 2040 timeframe.<br />

We are putting significant ef<strong>for</strong>t into building a strong<br />

foundation so that we are ready to unleash the full<br />

potential of SMRs, and projects in Canada are currently<br />

proceeding through three streams:<br />

p Stream 1 refers to near-term, grid-scale SMRs. Ontario<br />

<strong>Power</strong> Generation has announced that it is working<br />

towards a new grid-size SMR at its Darlington <strong>Nuclear</strong><br />

Station by about 2028.<br />

p Stream 2 refers to the development of two advanced<br />

Generation IV SMR designs. This is being led by New<br />

Brunswick, and NB <strong>Power</strong> envisions technology<br />

demonstration at the Point Lepreau site in the early to<br />

mid-2030s.<br />

p Stream 3 refers to a new class of micro SMRs, with<br />

potential to replace the use of diesel <strong>for</strong> remote communities<br />

and mines. Canadian <strong>Nuclear</strong> Laboratories (CNL)<br />

launched an Invitation <strong>for</strong> Demonstration in 2018, to<br />

invite SMR vendors to propose demonstration projects<br />

<strong>for</strong> siting at an AECL-owned, CNL-managed site.<br />

Interview<br />

The <strong>Nuclear</strong> Innovation Policy of Canada ı Ministry of Natural Resources Canada

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

INTERVIEW 20<br />

| Figure 1<br />

Electricity generation by source, Canada 1990-2019. (Source: www.iea.org/countries/canada)<br />

| Figure 2<br />

<strong>Nuclear</strong> electricity generation, Canada 1990-2019. (Source: www.iea.org/countries/canada)<br />

At least, an adopted regulatory framework is<br />

necessary <strong>for</strong> SMRs. Until now, which milestones<br />

have been achieved and is there any international<br />

cooperation between governments and institutions<br />

on the subject?<br />

Canada has a world-renowned regulator committed to<br />

safety and open to innovation, as well as a comprehensive<br />

plan to manage nuclear waste in the long-term. This<br />

combination of enabling elements, coupled with our<br />

commitment to nuclear excellence, means Canada is<br />

poised to lead the world.<br />

The Canadian <strong>Nuclear</strong> Safety Commission (CNSC)<br />

offers optional pre- licensing engagement with potential<br />

applicants, as well as a pre-licensing vendor design review<br />

service, to help identify any significant barriers to licensing<br />

SMR technologies in Canada and thereby minimize potential<br />

impediments during the licensing process. 12 SMR<br />

design vendors are currently engaged with the CNSC in<br />

the vendor design process and are at various stages of<br />

review.<br />

On international collaboration:<br />

In 2019, the CNSC signed a memorandum of cooperation<br />

with the United States <strong>Nuclear</strong> Regulatory Commission<br />

that could support more efficient reviews of SMRs.<br />

The CNSC and the United Kingdom (UK) Office <strong>for</strong><br />

<strong>Nuclear</strong> Regulation (ONR) recently (Oct 2020) signed two<br />

agreements to explore further collaboration and to more<br />

effectively regulate an ever-changing nuclear sector.<br />

A cornerstone of SMR technology to reach broad<br />

distribution as energy technology is serialization<br />

and the expected cost degression by number of<br />

installations. Are there already specific plans to<br />

realize this?<br />

Canada’s SMR Roadmap recognizes that as the technology<br />

matures, the cost of individual units will decrease. The<br />

Roadmap identifies several factors that will determine<br />

how quickly these costs decline, such as:<br />

p how many SMRs are built;<br />

p construction experience; and<br />

p the degree of standardization within SMR fleets.<br />

A major topic in discussions about nuclear power is<br />

waste management. What is the state of affairs in<br />

Canada particularly with regard to final disposal?<br />

The health, safety, and security of Canadians and the<br />

environment is the government’s top priority when it<br />

comes to regulating nuclear energy and materials. The<br />

Government of Canada is committed to ensuring that safe<br />

solutions are in place <strong>for</strong> managing radioactive waste now<br />

and into the future.<br />

Currently, all radioactive waste in Canada is safely<br />

managed in facilities licensed by the Canadian <strong>Nuclear</strong><br />

Safety Commission (CNSC) – Canada’s independent<br />

nuclear regulator.<br />

The <strong>Nuclear</strong> Waste Management Organization<br />

( NWMO) is responsible <strong>for</strong> implementing Canada’s plan<br />

<strong>for</strong> the safe, long-term management of used nuclear fuel –<br />

including that created using new or emerging technologies.<br />

The Government of Canada is committed to continuous<br />

improvement with respect to ensuring that safe solutions<br />

are in place <strong>for</strong> managing radioactive waste. For this<br />

reason, Canada launched an open and transparent engagement<br />

process to modernize Canada’s radioactive waste<br />

policy. Between now and fall 2021, the Government of<br />

Canada is conducting a review of Canada’s Radioactive<br />

Waste Policy. As part of this process, officials are engaging<br />

with stakeholders and talking to Canadians, including<br />

Indigenous peoples, to ensure all voices are heard.<br />

What are the differences <strong>for</strong> waste management<br />

between existing nuclear power plants and the<br />

smaller scaled SMR based nuclear power plants?<br />

Will the SMR path require changes to the waste<br />

management strategy or will it be part of existing<br />

concepts?<br />

All radioactive waste in Canada is being safely managed<br />

according to international standards at facilities that are<br />

licensed and monitored by the CNSC. Depending on the<br />

waste type and other characteristics, owners of waste from<br />

SMR technologies may be able to use existing concepts or<br />

may need to implement new solutions <strong>for</strong> their radioactive<br />

waste.<br />

Author<br />

Nicolas Wendler<br />

Head of Media Relations and Political Affairs<br />

KernD (Kerntechnik Deutschland e.V.)<br />

nicolas.wendler@kernd.de<br />

Interview<br />

The <strong>Nuclear</strong> Innovation Policy of Canada ı Ministry of Natural Resources Canada

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

“I am Personally Very Excited About<br />

Canadas’s Positioning as a Tier One<br />

<strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover<br />

in Small Modular Reactors“<br />

Interview with John Gorman ı President & CEO of Canadian <strong>Nuclear</strong> Association<br />

INTERVIEW 21<br />

The Canadian <strong>Nuclear</strong> Association represents an<br />

established nuclear industry which has decades of<br />

experience with nuclear technology. Can you give<br />

us a short overview of the nuclear sector in Canada?<br />

Let me start by saying that Canada is in a quite unique<br />

situation in terms of having both a vibrant nuclear ecosystem<br />

that is being fueled by the refurbishments of<br />

existing plants in our largest province of Ontario and in<br />

turn that is being used as a plat<strong>for</strong>m to do all sorts of<br />

innovation in Small Modular Reactors but also in other<br />

areas like medical isotopes. So, the combination of these<br />

two things, the healthy nuclear ecosystem and the<br />

innovation that we have going on in Small Modular<br />

Reactors is positioning Canada to provide climate change<br />

Small Modular<br />

Reactors will help us<br />

continue that track<br />

record and help others.<br />

solutions, the decarbonization<br />

of very important<br />

sectors of our economy<br />

here in Canada and by<br />

extension the ability to be<br />

a first mover in helping<br />

other nations around the<br />

world lower their GHGs. So, I am personally very excited<br />

about Canadas’s positioning as a tier one nuclear power<br />

and also as a first mover in Small Modular Reactors.<br />

In terms of actual statistics, we are a tier one nation<br />

being in this business <strong>for</strong> more than sixty years, with a very<br />

respected regulator and a highly respected track record in<br />

terms of the efficient and safe operation<br />

of nuclear plants. We currently<br />

have 12 different SMR technologies<br />

being evaluated and going through<br />

the review and licensing process in<br />

Canada making us a world leader in<br />

terms of the number of technologies<br />

and the speed with which we are developing them. CANDU<br />

technology is deployed in seven countries around the<br />

world and is still very actively involved in existing markets<br />

and developing markets. A great example of that is<br />

Romania, where they are very likely going to refurbish<br />

John Gorman<br />

Retiring coal in Ontario<br />

became and still is north<br />

Americas single largest<br />

carbon reduction initiative.<br />

President & CEO of Canadian <strong>Nuclear</strong> Association<br />

John Gorman is President & CEO of Canadian <strong>Nuclear</strong> Association, past President<br />

& CEO of the Canadian Solar Industries Association (CanSIA) and a Director on the<br />

board of the Energy Council of Canada (ECC). John served as Canada’s Designate<br />

to the <strong>International</strong> Energy Agency’s Executive Committee (PVPS) and was a<br />

Founder of the Canadian Council on Renewable Electricity (CanCORE). He’s using<br />

this experience to secure a leading role <strong>for</strong> nuclear energy at the heart of Canada’s<br />

energy transition. Be<strong>for</strong>e joining CanSIA, he was the Senior Vice President of<br />

Empower Energies, an innovative, global integrator of energy systems. He has<br />

served as a director on the boards of numerous community and corporate<br />

organizations, including one of the nation’s largest electric utilities. John has been<br />

recognized as one of Canada’s CLEAN50 and is the recipient of the “40 Under 40”<br />

business award <strong>for</strong> excellence in business practices. He was awarded the<br />

designation of Climate Project Ambassador by Nobel Laureate Al Gore in 2008.<br />

their two existing CANDU units and complete the<br />

construction of two additional units. So, Canada while<br />

being a smaller nation is a world leader in nuclear and we<br />

have accomplished some amazing things here from a<br />

climate perspective which I am eager to talk to you about<br />

and Small Modular Reactors will help us continue that<br />

track record and help others.<br />

You already mentioned the refurbishment programs.<br />

As I know of this is a quite unique feature,<br />

partially after long term shut downs. To understand<br />

this process, what determined the decisions about<br />

the refurbishment in both cases, i.e., the shut<br />

downs earlier and then the refurbishments and<br />

long-term operation later?<br />

This is an amazing story, that I hardly ever get asked about,<br />

so I am pleased to talk about it. Let me start with the punch<br />

line. Ontario, the largest province in Canada decided in the<br />

early 2000s to phase out all of our coal fired electricity.<br />

When we did that, coal fired electricity was providing<br />

about 25 % of Ontarios electricity, it was creating smog<br />

days and health problems and obviously<br />

emitting a lot of emissions. We replaced<br />

89 % of that coal fired electricity by<br />

bringing back online two units that had<br />

been shut down. So, in the process we<br />

were able to retire coal very quickly and<br />

retiring coal in Ontario became and still is<br />

north Americas single largest carbon reduction initiative.<br />

That’s the punch line. More specifically in 1997 Ontario<br />

Hydro, the utility, and the government made the decision<br />

to shut down two of our units because there was no<br />

demand <strong>for</strong> this electricity, there was a surplus. But by the<br />

Interview<br />

“I am Personally Very Excited About Canadas’s Positioning as a Tier One <strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover in Small Modular Reactors“ ı John Gorman

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

INTERVIEW 22<br />

early 2000s supply had become tight, we needed more<br />

electricity and at the same time we made the decision to<br />

phase out coal fired electricity. We addressed both of those<br />

issues by restarting four units and subsequently made the<br />

decision to refurbish a number of our units. We are likely<br />

going to close down two of them in the mid-2020s but we<br />

will continue to operate the majority of the 18 units in<br />

Ontario. So, this is the story: surplus of generation in 1997<br />

made the decision <strong>for</strong> shut downs, then as more generation<br />

was needed and the phase out of coal was decided we<br />

brought them back on and we undertook this refurbishment.<br />

At this moment the refurbishment is the single<br />

largest infrastructure project in Canada. It is a 26-billiondollar<br />

refurbishment that is taking place over ten years<br />

and it is employing a lot of people and driving a lot of<br />

innovation.<br />

This brings me to a follow-up question: when I<br />

remember the discussions, we had in Germany<br />

about longer operation of nuclear power plants in<br />

2009 and 2010 there was a fierce opposition of the<br />

green party and of environmental organizations.<br />

Were there discussions of that kind and organizations<br />

parties or movements opposed to the<br />

refurbishment of nuclear power plants in Canada?<br />

There are certainly detractors of nuclear power in Canada.<br />

We continue as an industry globally and in Canada to be<br />

exposed to that sort of stigma and misin<strong>for</strong>mation and not<br />

fact-based attitudes towards nuclear. But at the end of the<br />

day Canada has an outstanding record in terms of the safe<br />

operation and managements of its fleet. Canadians<br />

recognize that we are a world leader<br />

in nuclear power and clearly in the<br />

end the arguments and support in<br />

favor of refurbishment outweighed<br />

the detractors. Our country is very<br />

large, there are ten different provinces<br />

which are responsible <strong>for</strong> their own electricity supply so it<br />

becomes a very regional discussion rather than a national<br />

discussion. This might be a key difference between Canada<br />

and Germany. There is one thing that we know <strong>for</strong> certain:<br />

the more people know about nuclear the more supportive<br />

they are. In the provinces where we do have nuclear power<br />

like New Brunswick or Ontario or in Saskatchewan where<br />

there are uranium operations, these regions are very com<strong>for</strong>table<br />

with nuclear or at least much more supportive<br />

than other provinces.<br />

<strong>Nuclear</strong> technology is not just about nuclear power<br />

plants, there are also very important other sectors.<br />

One of them is isotope production <strong>for</strong> many<br />

purposes including medical ones. In 2018 a major<br />

production facility in Canada that was important<br />

globally, the NRU reactor, was taken out of production<br />

and important capacity was lost. How was<br />

it compensated <strong>for</strong> or was it compensated <strong>for</strong>?<br />

It has been compensated <strong>for</strong> in a very interesting way.<br />

Firstly, the NRU had to be taken down because it served its<br />

lifespan. But we continue to have radioisotope production<br />

in our existing conventional power reactors and in other<br />

research reactors as well as particle accelerators such as<br />

TRIUMF and Canadian Light Source<br />

in western Canada. Despite the end of<br />

operation of NRU, we still have other<br />

research reactors and particle accelerators<br />

that are fulfilling that need.<br />

However, it has also spurred real<br />

The more people know<br />

about nuclear the more<br />

supportive they are.<br />

innovation here in Canada using our existing CANDU<br />

reactors. So, what we are seeing is that our two largest<br />

operators, Bruce <strong>Power</strong> and Ontario <strong>Power</strong> Generation<br />

have partnered with companies in the private sectors such<br />

as BWXT and isoGEN to produce isotopes from conventional<br />

reactors. This is really fascinating. There is no need<br />

to interrupt the operation of the units in any way. Ontario<br />

<strong>Power</strong> Generation and BWXT are beginning to produce<br />

Molybdeneum-99 at the Darlington <strong>Nuclear</strong> Association<br />

and Bruce <strong>Power</strong>, BWXT and Isogen similarly are beginning<br />

to produce Lutetium-177 <strong>for</strong> cancer therapy. At the<br />

same time, we continue to produce a large portion of the<br />

worlds supply of isotopes through our other assets. This<br />

includes more than 70 per cent of the global supply of<br />

Cobalt-60 and about 60 per cent of the world market <strong>for</strong><br />

Iodine-129 is produced here as well. We have adapted and<br />

used innovation to replace the isotope production that was<br />

shut down.<br />

Let’s get back to power, the major question <strong>for</strong><br />

many countries nowadays given all the climate<br />

discussions and climate targets. What is the longterm<br />

perspective <strong>for</strong> nuclear power in Canada and<br />

how is it included in Canadian or provincial energy<br />

and climate strategies?<br />

The long-term perspective <strong>for</strong> nuclear power in Canada is<br />

extremely bright <strong>for</strong> the reasons we have already spoken<br />

about. The refurbishment of our CANDU power plants in<br />

Ontario is the largest infrastructure program in Canada. It<br />

is going to keep those plants operating well into the 2060s<br />

and they are providing 15 per cent of Canadas clean<br />

electricity and a healthy nuclear ecosystem<br />

that is the foundation <strong>for</strong> other work that we<br />

are doing in Small Modular Reactors and<br />

isotopes. With this very strong foundation of<br />

the refurbishments going on with a large work<br />

<strong>for</strong>ce and innovation we have become a first<br />

mover in Small Modular Reactors. The government has<br />

started funding a number of the SMR-technologies that are<br />

under review and licensing and we expect to see more<br />

funding announcements in a short number of weeks<br />

coming. We also have an extraordinary level of coordination<br />

between government and industry and the provinces<br />

in the development and deployment of Small Modular<br />

Reactors. And this is quite exceptional and exciting: four of<br />

our provinces have signed a Memorandum of Understanding<br />

on the development and deployment of SMR. The<br />

federal government has come out and identified nuclear as<br />

being needed and essential <strong>for</strong> net zero in 2050, our<br />

national goal. So, we have both the federal government<br />

identifying nuclear as being essential to reaching net zero<br />

2050 and four provinces and their utilities who have<br />

agreed on a business plan <strong>for</strong> the development and deployment<br />

of SMR in their regions. When you combine this with<br />

our very progressive regulator, the Canadian <strong>Nuclear</strong><br />

Safety Commission, which is very well suited to evaluate<br />

and work with innovative technologies much more so than<br />

some of the very prescriptive regulators we see in other<br />

places, it really becomes a competitive advantage <strong>for</strong> us.<br />

In fact, when you look at Canadas commitment around<br />

climate change which is very aggressive with the objective<br />

The federal government has come<br />

out and identified nuclear as being<br />

needed and essential <strong>for</strong> net zero<br />

in 2050, our national goal.<br />

of net zero in 2050 where<br />

nuclear is acknowledged as a<br />

key element of that energy<br />

plan and we have both a long<br />

term set of operating assets<br />

producing 15 per cent of our<br />

Interview<br />

“I am Personally Very Excited About Canadas’s Positioning as a Tier One <strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover in Small Modular Reactors“ ı John Gorman

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

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INTERVIEW 23<br />

electricity and a world leading advantage on the development<br />

of SMR, so the long-term perspectives of nuclear in<br />

Canada are assured.<br />

To realize the opportunities that exist with SMRs<br />

regulatory issues are quite important. They need<br />

certain adaptations compared to larger units and<br />

apparently this is working well in Canada as I can<br />

conclude from what you said. But is there also work<br />

going on to achieve some standardized regulations<br />

on SMR designs that are in the pipeline, are you<br />

cooperating with the US and the UK and maybe at<br />

some point with the European Union too because<br />

there probably soon will be an international market<br />

<strong>for</strong> this type of plants.<br />

You identified one of the most important issues here.<br />

Globally, to realize the benefits of SMR will need some<br />

standardization in terms of regulation. As you know this is<br />

a departure from a long history of nuclear power being a<br />

very nationally driven sector. Each country focused on a<br />

particular type of technology and set up a regulatory<br />

framework <strong>for</strong> this technology. Canada is a good example<br />

<strong>for</strong> this with its CANDU- technology. Of course, SMR<br />

depend on being mass produced and manufactured<br />

in manufacturing settings, making it more of a product<br />

and commodity. And because of their smaller size these<br />

units cannot af<strong>for</strong>d the regulatory expense of needing to<br />

be certified in every country that they enter into. So,<br />

finding regulatory harmonization is key to SMR success<br />

going <strong>for</strong>ward. What we have done here in Canada as the<br />

Canadian <strong>Nuclear</strong> Association is to begin working with our<br />

sister organization in the US, the NEI, and we have set up a<br />

US-Canada regulatory task <strong>for</strong>ce that is looking at these<br />

issues. But more importantly our regulators, the CNSC<br />

here in Canada and the NRC in the United States have<br />

signed a Memorandum of Cooperation and they are<br />

working on regulatory harmonization. So, we recognized<br />

the need here in north America <strong>for</strong> this standardization. At<br />

the same time, we have reached out to the <strong>Nuclear</strong> Industry<br />

Association in the UK and we are working with them as do<br />

our governments on these same issues. We have now<br />

signed a Memorandum of Understanding with our<br />

counter part in Europe, Foratom, and we will be talking<br />

about similar issues. But right now, the most developed<br />

push on this front is between Canada and the United States<br />

and has started with the UK and we hope to expand this to<br />

Europe as well.<br />

Is this the major aspect of the MoU with Foratom or<br />

are there other objectives too?<br />

There are other objectives as well. Firstly, the nuclear<br />

cooperation between Canada and Europe goes back <strong>for</strong><br />

decades and specifically Canadian CANDU reactors have<br />

been in service in Romania <strong>for</strong> nearly thirty years. So, this<br />

MoU at the highest level addresses the need <strong>for</strong> greater<br />

dialogue and the exploration of the role of nuclear in<br />

effective environmental stewardship and a subtext to that<br />

would be this work that we have to do in rationalizing<br />

regulation around SMR. But the MoU has essentially three<br />

components to it: one is around advocacy and trying to<br />

advocate <strong>for</strong> more explicit inclusion <strong>for</strong> nuclear energy in<br />

Canada and the EU and that includes the idea of sustainable<br />

finance, taxonomy which I know that the European Union<br />

is grappling with right now. The second point is that we<br />

Interview<br />

“I am Personally Very Excited About Canadas’s Positioning as a Tier One <strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover in Small Modular Reactors“ ı John Gorman

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

INTERVIEW 24<br />

want to support innovation, particularly in SMR and<br />

advanced reactors which is something we flagged in the<br />

MoU and the regulatory work also falls into that. And we<br />

also want to find initiatives where we can work together to<br />

promote nuclear as a clean source of electricity that is<br />

needed <strong>for</strong> climate goals.<br />

But what I wanted to say about this idea of taxonomy<br />

and that nuclear is clean and the importance of that: the<br />

nuclear industry in Canada<br />

The nuclear industry in Canada like in<br />

other nations has had to work very<br />

hard with stake holders and policy<br />

makers to explicitly acknowledge<br />

nuclear power as clean energy and<br />

we have succeeded in that in Canada.<br />

like in other nations has had to<br />

work very hard with stake<br />

holders and policy makers to<br />

explicitly acknowledge nuclear<br />

power as clean energy and<br />

we have succeeded in that<br />

in Canada. So, recently just<br />

be<strong>for</strong>e Christmas the federal<br />

government explicitly identified<br />

nuclear as clean and essential to net zero 2050. And<br />

<strong>for</strong> us this has been important as we see in this increasingly<br />

carbon constrained world all of the policies and<br />

funding programs are increasingly directed toward clean<br />

technologies. We worked very hard <strong>for</strong> that and I am<br />

hoping that we can share some of the experiences and<br />

lessons that we learned here in Canada around this issue<br />

with Europe through our collaboration with Foratom.<br />

A last time back to the SMR projects: How far advanced<br />

are the projects trying to demonstrate the<br />

feasibility of new kinds of reactor designs?<br />

SMR are going to enter the market in Canada much sooner<br />

than people expect. Our largest utility, Ontario <strong>Power</strong><br />

Generation, has announced that it will be net zero by 2040.<br />

But as part of that it will connect its first SMR at its Darlington<br />

Facility in 2028. Sask<strong>Power</strong>, Saskatchewan <strong>Power</strong>, is<br />

working in partnership with them to roll out multiple units<br />

in Saskatchewan with the same technology right on the<br />

heels with OPG. And we have other technologies, including<br />

very small reactor technologies, that are projecting that<br />

they will be in the market even sooner, by 2026. There is an<br />

amazing story here about the application of very small reactors<br />

in a number of Canadas most important sectors. The<br />

market demand in Canada <strong>for</strong> very small reactors is about<br />

5.3 billion Dollars between 2030 and 2040. And much of<br />

that market demand is in the mining industry using SMRs<br />

<strong>for</strong> their high temperature heat, to generate electricity but<br />

also to produce hydrogen. Many of these SMRs are going to<br />

be used in heavy industry like cement and steel, fertilizer<br />

production, in the oil sands, which is such an important<br />

part of our economy. These SMRs are going to be used to<br />

generate high temperature steam to clean up the extraction<br />

process <strong>for</strong> oil and gas.<br />

So, Canada is not only a first mover in SMRs but it has a<br />

set of industries that are able to take advantage of the<br />

unique capabilities of SMRs while decarbonizing those<br />

sectors and ensuring that Canadas natural resource sector<br />

and the materials that we produce are going to be<br />

competitive in this increasingly carbon constrained world.<br />

It is really a beautiful dynamic that we have here in Canada<br />

of being able to develop a handful of SMR technologies<br />

that are going to be tailor made to address the particular<br />

GHG reduction issues in our industries. And our hope of<br />

course is that we will be able to use those technologies to<br />

help other nations decarbonize their heavy industries and<br />

natural resource sectors so that we can contribute to the<br />

world moving to a low carbon economy.<br />

And finally, I want to come to nuclear waste<br />

management. What are Canadas plans <strong>for</strong> waste<br />

management?<br />

Readers of <strong>atw</strong> surely will know that the nuclear industry<br />

is a very responsible manager of nuclear waste and that the<br />

facts on spent fuel are actually quite a positive story. We<br />

are the only energy generating sector that is entirely<br />

responsible <strong>for</strong> the all of the byproducts that it produces<br />

and we prepay <strong>for</strong> its safe management<br />

and storage. We don’t emit<br />

pollution to the environment and<br />

we produce so little spent fuel<br />

because uranium is so power dense.<br />

We have been operating <strong>for</strong><br />

60 years providing 15 per cent of<br />

the nations electricity and we<br />

barely fill up a few hockey rings to<br />

the floor boards with spent fuel. It<br />

is exceptionally well managed, no one has ever been<br />

harmed, let alone killed by spent fuel. If you look at our<br />

entire life cycle from uranium mining to storing the spent<br />

fuel and all of our byproducts, we have the lowest carbon<br />

footprint of any electricity generating source, only wind is<br />

comparable. We have an amazing story to tell on that front<br />

that people don’t understand.<br />

But we also recognize that we need a permanent<br />

solution <strong>for</strong> storing the waste. We have been managing the<br />

waste exceptionally well to this point but especially in<br />

Canada where we are extending the life of our nuclear<br />

plants <strong>for</strong> another 40 years and because of the advent of<br />

SMR we need a permanent storage <strong>for</strong> the waste. So, there<br />

are currently two communities, two land-locked areas that<br />

have been short listed <strong>for</strong> a deep geological repository,<br />

South Bruce in southern Ontario and Ignace in northwestern<br />

Ontario and we have a nuclear waste management<br />

organization that is overseeing the site selection <strong>for</strong><br />

this area. We are going to follow the example of Finland<br />

here which is on track to have their DGR by 2023 and we<br />

are going to continue managing our spent fuel until that<br />

deep geological repository is completed. Another thing<br />

that we are excited about is that a number of the technologies<br />

that are reviewed and hopefully licensed here in<br />

Canada will also be reusing the spent fuel from the CANDU<br />

reactors as their fuel which adds some additional avenues<br />

<strong>for</strong> properly storing or using the spent fuel.<br />

Interviewer<br />

Nicolas Wendler<br />

Head of Media Relations and Political Affairs<br />

KernD (Kerntechnik Deutschland e.V.)<br />

nicolas.wendler@kernd.de<br />

Interview<br />

“I am Personally Very Excited About Canadas’s Positioning as a Tier One <strong>Nuclear</strong> <strong>Power</strong> and also as a First Mover in Small Modular Reactors“ ı John Gorman

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

<strong>Nuclear</strong> <strong>Power</strong> is Dead,<br />

Long Live <strong>Nuclear</strong> Energy!<br />

Simon Wakter<br />

The supposed demise of nuclear power has long been asserted by those opposed to the technology. But as the world<br />

struggles to meet the Paris Agreement climate goals of limiting global temperature increase by 1.5 °C to 2 °C compared<br />

to pre-industrial levels, neither the historic contribution nor the important future role of nuclear energy should be<br />

ignored. <strong>Nuclear</strong> is an indispensable tool to meet the dual challenge of meeting an increasing energy demand while<br />

phasing out fossil fuels. To paraphrase the speech of Robert Cecil at the final meeting of the League of Nations – nuclear<br />

power is dead, long live nuclear energy!<br />

Many countries have made pledges to decrease emissions<br />

or set net zero goals by the year 2050. This leaves just<br />

under 30 years to dramatically reduce emissions, while<br />

global energy use is expected to continue rising. As pledges<br />

are often phrased in terms of reductions in relation to 1990<br />

emission levels, it also means that just over 30 years have<br />

passed since the ‘benchmark’ year. In those 30 years, the<br />

share of fossil fuels in both electricity and total energy<br />

consumption has remained virtually unchanged, at around<br />

65 percent and 85 percent respectively. The share of<br />

nuclear energy in electricity production today is around<br />

ten percent, a drop from a high of 17.5 percent in 1996. The<br />

drop in nuclear production is only in terms of the share of<br />

total production – nuclear electricity production has<br />

actually increased in absolute terms, but world electricity<br />

demand has roughly doubled in the same period. Total<br />

energy demand has increased by about 60 percent.<br />

Higher energy and electricity consumption is correlated<br />

with higher development and human welfare indicators.<br />

The increased access to and use of electricity has contributed<br />

greatly to the improved standards of living <strong>for</strong><br />

hundreds of millions of people. But many people still lack<br />

access to electricity and much of the worlds electricity and<br />

energy consumption is still fossil fuelled. As has become<br />

abundantly clear, energy production must increase but<br />

must also be clean.<br />

Globally, the combined share of low carbon technologies<br />

amounts to approximately 35 percent of total<br />

electricity production. <strong>Nuclear</strong> accounts <strong>for</strong> 30 percent of<br />

this low carbon electricity, second only to hydro power’s<br />

46 percent. In advanced economies, nuclear energy<br />

supplies 40 percent of low carbon electricity. 1,2 Within the<br />

EU, just over half of electricity is produced from low carbon<br />

technologies and nuclear supplies almost half of this clean<br />

electricity. 3<br />

The world now faces the enormous, twofold challenge<br />

of transitioning to clean energy while meeting the increase<br />

in energy and electricity demand.<br />

| Figure 1<br />

Low carbon electricity generation in advanced economies in 2018. 1,2<br />

added on top of the daily trials of coronavirus lockdown.<br />

The lack of electricity, frequent blackouts and interruptions<br />

to internet and running water made working or<br />

studying from home virtually impossible.<br />

In Japan, a cold spell coupled with an already tight LNG<br />

market in Asia brought power prices to record highs.<br />

Intraday power prices reached over ¥250/kWh, or roughly<br />

€2/kWh, with spot prices topping out at around<br />

¥155/kWh, or €1,20/kWh.<br />

In Texas, arctic temperatures brought electricity<br />

demand surging toward all-time highs and prices topped<br />

out at over $9,000/MWh, or €7,700/MWh. When power<br />

plants (primarily gas power plants) dropped from the grid<br />

due to the cold, grid operators initiated rotating outages<br />

which then turned into lasting blackouts <strong>for</strong> millions of<br />

peoples.<br />

Both in Texas and in Japan, utilities as well as consumers<br />

have been hit by the record breaking prices leading to<br />

extraordinary corporate and personal financial difficulties.<br />

25<br />


Energy enables modern lives<br />

Access to af<strong>for</strong>dable energy is the foundation of modern,<br />

civilised societies. The ability to use energy when and<br />

where it is needed enables almost every other human<br />

activity. This has been illustrated and rein<strong>for</strong>ced by events<br />

during the past year. In Libya, already strenuous conditions<br />

have worsened through prolonged power outages<br />

Electricity is key<br />

The key to solving a large part of the decarbonisation challenge<br />

is electricity. Dramatic cost reductions in wind and<br />

solar production has redrawn the map and enabled a large<br />

scale roll out of clean electricity only ever be<strong>for</strong>e seen in<br />

the nuclear energy programmes of countries such as Sweden<br />

and France.<br />

1 <strong>Nuclear</strong> <strong>Power</strong> in a Clean Energy System, <strong>International</strong> Energy Agency (IEA), May 2019<br />

2 European Commission Joint Research Centre, Technical assessment of nuclear energy with respect to the ‘do no significant harm’ criteria of Regulation (EU) 2020/852<br />

(‘Taxonomy Regulation’), Petten, 2021, JRC124193<br />

3 Eurostat, Electricity production by source, EU-27, 2019, https://ec.europa.eu/eurostat/statistics-explained/index.php/Electricity_generation_statistics_–_first_results<br />

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<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


Electrification also brings with it great potential <strong>for</strong><br />

improvements in efficiency. For example, the electrification<br />

of transportation through electric vehicles offers<br />

significant efficiency improvements compared to fossil<br />

fuelled cars.<br />

Large scale production of hydrogen through electrolysis<br />

enables the decarbonisation of several industry processes,<br />

such as iron production. Direct electrification through<br />

Electric Arc Furnaces, EAF, enables fossil free steel<br />

production.<br />

It’s a power grid, not an energy grid<br />

Electrification is a versatile tool <strong>for</strong> decarbonisation, but<br />

places high demands on the power grid. Analysing and<br />

designing systems based on the required energy on a yearly<br />

basis is not sufficient.<br />

Be<strong>for</strong>e transmission of power through alternating<br />

current was discovered by Nikola Tesla at the end of the<br />

19 th century, so called flatrod systems (German: Kunstgestänge<br />

or Stangenwerk) were used to transfer power.<br />

Flatrod systems, made up of timbers which were tied or<br />

joined together, made it possible to transfer power both<br />

horizontally and vertically over distances up to a few<br />

kilometres.<br />

Similarly to the flat rod system swinging back and <strong>for</strong>th,<br />

alternating current is based on the current constantly<br />

changing direction. Just like the flatrods, it is the oscillations<br />

that transmit the power. In Europe, the oscillation<br />

takes place 50 times per second and must always stay at<br />

this constant frequency. A multitude of instrumentation<br />

and control systems are in place to make sure the system is<br />

always balanced – the production and load must always be<br />

equal.<br />

The economic market <strong>for</strong> trading, called the power<br />

market, is not really a market <strong>for</strong> power but rather <strong>for</strong><br />

energy. Energy becomes a commodity to be produced,<br />

distributed and consumed. This step away from the<br />

physical concept of energy enables competition but also<br />

brings difficulties.<br />

In order to function properly, and in turn enable the<br />

market, the power grid also requires balancing and<br />

ancillary services. Such services may consist of inertia,<br />

reactive power or short circuit power, all of which have so<br />

far been provided largely <strong>for</strong> free by large generators such<br />

as nuclear power plants. While markets exist <strong>for</strong> some<br />

services, e.g. <strong>for</strong> frequency reserve measures, it is likely<br />

that new markets <strong>for</strong> such services will be necessary in the<br />

future to ensure the functioning of the power system. 4<br />

<strong>Nuclear</strong> can already provide many of these services<br />

today and with the right incentives it is possible to expand<br />

the services, e.g. through integrating thermal storage with<br />

molten salt in advanced reactors.<br />

It’s not all electricity<br />

Electrification is key to decarbonisation, but does not<br />

paint the full picture. Some sectors, e.g. energy-intensive<br />

industry and heavy-duty transportation (such as long-haul<br />

aviation, maritime shipping and some road freight), are<br />

| Figure 2<br />

Global greenhouse gas emissions by sector. 4 This is shown <strong>for</strong> the year 2016 – global greenhouse gas emissions were 49.4 billion tonnes CO 2 eq.<br />

4 Ritchie, H.; Our World in Data – Sector by sector: where do global greenhouse gas emissions come from? https://ourworldindata.org/ghg-emissions-by-sector<br />

Serial | Major Trends in Energy Policy and <strong>Nuclear</strong> <strong>Power</strong><br />

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<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

more challenging to decarbonise and will require greater<br />

ef<strong>for</strong>t and novel approaches. These sectors, heavy industry<br />

and heavy-duty transports, make up almost one-third of<br />

global carbon emission.<br />

Iron and steel production makes up seven percent of<br />

greenhouse gas emissions. The emissions stem from two<br />

sources – from the fossil fuels used to heat and power the<br />

process, and from the coking coal used as raw material in<br />

the reduction process itself. Low carbon energy can replace<br />

the fossil fuels used to power the process, and clean<br />

hydrogen can replace the coking coal used <strong>for</strong> the reduction<br />

of oxygen in the iron oxide. Hydrogen is also an important<br />

feedstock in ammonia and fertilizer production as well as<br />

<strong>for</strong> refining fossil fuels, biofuels or plastics. This hydrogen<br />

demand, today around 70 million tons per year, is currently<br />

met almost exclusively by production from fossil fuels.<br />

The production of cement produces around three<br />

percent of global greenhouse gas emissions. Again, the<br />

emissions stem from two sources. In this case roughly<br />

60 percent of emissions are inherent to the calcining<br />

process itself, while the remaining 40 percent arise from<br />

the use of fossil fuels <strong>for</strong> heating the production process.<br />

Electrification and fossil free fuels can replace the fossil<br />

fuels, but emissions inherent to the calcining process will<br />

require carbon capture technologies.<br />

A large part of transportation can most likely be solved<br />

through electrification, but heavy-duty transportation will<br />

require higher density energy storage or fuels. This could<br />

be in the <strong>for</strong>m of hydrogen, ammonia or other electrofuels<br />

such as synthetic hydrocarbons which can be made<br />

through the Fischer-Tropsch process, combining carbon<br />

monoxide (from carbon capture) and hydrogen into liquid<br />

hydrocarbons.<br />

Energy use in buildings is another major sector, behind<br />

almost one-fifth of emissions. Although electrification is a<br />

major part of the solution, a large share of the property<br />

stock relies on fossil gas <strong>for</strong> heating. Replacing gas boilers<br />

with ground source or air source heat pumps could prove<br />

prohibitively expensive – especially <strong>for</strong> those in energy<br />

poverty, already struggling with a “heat or eat”-dilemma.<br />

Existing grids, built <strong>for</strong> gas heated buildings, would<br />

struggle to serve the increased power demand during cold<br />

or hot spells. Hydrogen, either replacing or mixed into existing<br />

gas pipelines, and district heating have both been<br />

proposed as solutions.<br />

The scale of energy use in buildings is often overlooked.<br />

For example, final energy consumption <strong>for</strong> heating in<br />

German residential buildings is roughly equal to the total<br />

German electricity production, approximately 560 TWh<br />

per year. Since 95 % of this heating demand is met with<br />

fossil fuels, heating the country’s 40 million homes<br />

produces almost ten percent of Germany’s greenhouse gas<br />

emissions. Even partially meeting this energy demand<br />

with clean hydrogen would require an extraordinary<br />

amount of electricity <strong>for</strong> electrolysis – hydrogen from fossil<br />

methane is not carbon neutral, especially when accounting<br />

<strong>for</strong> flaring and fugitive emissions – meaning electrification<br />

and district heating may prove to be more sensible<br />

solutions. <strong>Nuclear</strong> CHP plants could provide cities with<br />

both electricity and district heating, which is already done<br />

at several locations today. District heating reactors, that<br />

produce only heat and not power, are also being developed<br />

and constructed.<br />

All in all, industry and transport together with energy<br />

use in buildings make up almost 60 percent of global<br />

emissions. <strong>Nuclear</strong> is an important tool in these “hard-toabate”<br />

sectors.<br />

Small solutions to big problems<br />

A new wave of modern small and advanced modular<br />

reactors are currently being designed, licensed and built<br />

all over the world. These reactors have increased passive<br />

safety features, reduced or no emergency planning zone<br />

and significant potential <strong>for</strong> cost savings.<br />

To compensate <strong>for</strong> lack of economies of scale, otherwise<br />

associated with larger reactors, smaller reactors take<br />

advantage of simpler construction principles, modularity<br />

and standardisation to decrease cost. The smaller size also<br />

decreases initial capital expenditure, construction time<br />

and overall risk. This creates a feedback loop which works<br />

to decrease the overall cost of capital, which <strong>for</strong> traditional<br />

large scale reactors can account <strong>for</strong> up to 70 percent of<br />

total costs.<br />

More is more when it comes to heat output<br />

Many advanced reactors work at significantly higher<br />

temperatures than conventional reactors. Where today’s<br />

boiling and pressurised water reactors work at temperatures<br />

around 300 °C, advanced reactors cooled with<br />

molten lead, sodium or gas work at temperatures between<br />

500 and 700 °C. This means higher efficiencies and opens<br />

up a range of new applications.<br />

Advanced nuclear reactors, providing high temperature<br />

heat and electricity now become an attractive option <strong>for</strong><br />

hydrogen production, process heat, district heating,<br />

desalination and carbon capture through direct air capture<br />

(DAC). <strong>Nuclear</strong> energy can be integrated across the<br />

manufacturing process in many applications, e.g. <strong>for</strong><br />

production of iron and steel where high temperature<br />

electrolysis, electricity production and large amounts of<br />

high temperature heat can dramatically reduce emissions<br />

and improve efficiencies.<br />

Coal power remains largely unthreatened as the world’s<br />

main source of electricity production, with global output<br />

increasing to over 4,630 TWh in 2020 5 . One solution, as<br />

explored in an article by Qvist et al. 6 , is “retrofit decarbonisation”<br />

– a term which includes repowering of coal<br />

units with low-carbon energy technology. The prospect of<br />

| Figure 3<br />

Steam temperature comparison, nuclear and coal power plants. 6<br />


5 Ember, Global Electricity Review 2021, https://ember-climate.org/project/global-electricity-review-2021/<br />

6 Qvist, S.; Gładysz, P.; Bartela, Ł.; Sowiżdżał, A. Retrofit Decarbonization of Coal <strong>Power</strong> Plants—A Case Study <strong>for</strong> Poland. Energies 2021, 14, 120.<br />

https://doi.org/10.3390/en14010120<br />

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advanced reactors capable of high temperature output,<br />

suitable <strong>for</strong> existing coal powered steam turbines, and the<br />

fact that more than half of the world’s 2,000 GWe coal fleet<br />

is less than 14 years old combine to create a compelling<br />

argument.<br />

Integrating and reusing the existing site, equipment<br />

(cooling water systems and steam cycle) and grid connection<br />

could lower upfront capital costs by 28 – 35 percent<br />

and levelized cost of electricity by 9 – 28 percent compared<br />

to a greenfield installation.<br />

Standardisation, harmonisation, cooperation<br />

To realise the potential of small and advanced modular<br />

reactors it is essential to avoid unnecessary, countryspecific<br />

design modifications or changes to documentation.<br />

Policymakers and regulators must work to ensure<br />

stability and predictability in the licensing process as well<br />

as to increase international harmonisation of licensing<br />

requirements.<br />

Redesigning SMRs <strong>for</strong> each country would quickly<br />

become prohibitively expensive, which means licensing<br />

regimes need to be per<strong>for</strong>mance-based rather than<br />

prescriptive. Licensing should also be risk-in<strong>for</strong>med and<br />

technology-inclusive. In the cases where that is difficult or<br />

not possible it is important that regulators agree on<br />

terminology and definitions, possibly through a taxonomy<br />

of licensing requirements. One example is the definition of<br />

active and passive systems, which has varying definitions<br />

between different countries and different organisations.<br />

Increasing standardisation and harmonisation through<br />

international cooperation is a low cost, no-regrets option<br />

<strong>for</strong> countries wishing to expand the use of nuclear energy.<br />

Enabling nuclear energy<br />

<strong>Nuclear</strong> energy is a flexible solution which can help solve<br />

many challenges – providing electricity and heat <strong>for</strong><br />

several applications ranging from industrial process heat,<br />

through hydrogen production to carbon capture and<br />

production of electrofuels. <strong>Nuclear</strong> also provides firm<br />

power and grid stability, aiding in the integration of<br />

variable renewable energy sources.<br />

In addition to contributing to the historic and future<br />

decarbonisation of energy use in the west, expansion of<br />

nuclear energy is a promising solution <strong>for</strong> economies in<br />

transition and developing economies seeking to improve<br />

living standards while reducing greenhouse gas emissions.<br />

Over 30 “nuclear new-comers” have concrete plans to<br />

develop nuclear energy projects in the coming decade.<br />

Recent research by Kenton de Kirby and Jessica Lovering<br />

offer important insights and lessons on how to enable the<br />

success of nuclear energy in emerging markets.<br />

In their report 7 , de Kirby and Lovering find that local<br />

opposition to projects in emerging markets differs from the<br />

anti-nuclear movement of the 1970’s which, in highincome<br />

countries, has protested nuclear on ideological and<br />

absolutist grounds. The authors warn against projecting<br />

fundamental anti-nuclear sentiments onto activists in<br />

newcomer countries. Instead, local opposition is largely<br />

based in a worry about livelihoods, lack of local economic<br />

benefit and government corruption as well as the government’s<br />

inability to respond effectively in the event of an<br />

accident.<br />

To gain public trust and consent, stakeholders must<br />

establish strategies and take concrete action to improve<br />

transparency, involve the local community and work to<br />

understand activist’s concerns – all while addressing<br />

perceived risks and building trust in regulators and<br />

relevant institutions. The report goes on to offer concrete<br />

ideas and best practices <strong>for</strong> effective engagement with<br />

local communities.<br />

<strong>Nuclear</strong> power is dead,<br />

long live nuclear energy!<br />

From harmonisation and standardisation of licensing<br />

requirements in established nuclear energy countries to<br />

stakeholder engagement in emerging economies, nuclear<br />

energy (like other clean energy technologies) must be<br />

enabled through proactive work from politicians, policymakers<br />

and international institutions.<br />

75 years ago, in the spring of 1946, Robert Cecil<br />

participated in the final meeting of the League of Nations<br />

in Geneva. Lord Cecil was one of the architects of the<br />

League and participated during the creation of the United<br />

Nations. He ended his final speech at the meeting with the<br />

words: “The League is dead, long live the United Nations.”<br />

Whether the world successfully eradicates global<br />

poverty while managing climate change will be largely<br />

determined by the events in emerging markets. <strong>Nuclear</strong><br />

energy is an indispensable tool to meet the dual challenge<br />

of increasing energy consumption while phasing out fossil<br />

fuels. Just as the League was succeeded by the United<br />

Nations, <strong>for</strong>med to meet new challenges, so our view of<br />

nuclear must grow to meet the challenges that lay ahead.<br />

To paraphrase the speech of Robert Cecil – <strong>Nuclear</strong> power<br />

is dead, long live nuclear energy!<br />

Author<br />

Simon Wakter<br />

Expert Advisor, Energy<br />

Simon Wakter is a nuclear energy engineer working as Expert Advisor in energy<br />

systems at the consultancy firm AFRY, with experience from technical consultancy in<br />

nuclear safety and licensing as well as from advising on different projects ranging<br />

from SMRs to hydrogen. Mr. Wakter is also a board member of the Swedish <strong>Nuclear</strong><br />

Society and one of the founders of the Swedish Ecomodernists.<br />

7 de Kirby, K; Lovering, J. A Socially Sustainable Future <strong>for</strong> <strong>Nuclear</strong> Energy in Emerging Markets, 2021<br />

https://thebreakthrough.org/issues/energy/socially-sustainable-nuclear-in-emerging-markets<br />

Serial | Major Trends in Energy Policy and <strong>Nuclear</strong> <strong>Power</strong><br />

<strong>Nuclear</strong> <strong>Power</strong> is Dead, Long Live <strong>Nuclear</strong> Energy! ı Simon Wakter

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Europe on the Road to a Major Disaster<br />

When Physics and the Laws of Nature Are Disregarded,<br />

a Rude Awakening Looms<br />

Herbert Saurugg<br />

Introduction The European electricity supply system is undergoing a radical upheaval. What is essential in terms<br />

of climate protection policy is leading to the interconnected system becoming increasingly fragile, because the approach<br />

which is being adopted is non-systemic. Instead of sound basic knowledge, it is wishful thinking and knee-jerk reactions<br />

which are determining the approach, and this could end in the greatest catastrophe since World War II.<br />

We can still turn away from this disastrous<br />

route. This would require rapid<br />

and decisive political action, but there<br />

is no evidence of this at present. A<br />

systemic conversion of the European<br />

electricity supply system into robust<br />

energy cells would have to be initiated<br />

immediately to reduce the looming<br />

susceptibility to failure. From a<br />

technical point of view, this would not<br />

be a problem, since the necessary<br />

knowledge is available and this<br />

conversion could be undertaken while<br />

the system is in operation.<br />

The greatest obstacle here is the<br />

fact that we have so far successfully<br />

thought in terms of large-scale<br />

technology, and this would have to be<br />

supplemented by complementary<br />

complexity and networked thinking,<br />

and adopted as the maxim. This<br />

requires appropriate framework conditions.<br />

The current route is pointing<br />

more in the opposite direction, however,<br />

towards centralization, but this<br />

makes it impossible to manage a system<br />

which is becoming increasingly<br />

complex.<br />

The electricity supply is our most<br />

important lifeline, without which our<br />

modern society could be destroyed<br />

within only a few days. We ought to<br />

prevent this from happening.<br />

On January 8, 2021 we experienced<br />

the second most serious<br />

major disruption so far in the<br />

European power supply system<br />

(ENTSO-E/RG CE – Regional Group<br />

Central Europe). The consequences<br />

were very minor compared to the<br />

first one on November 4, 2006. On<br />

that occasion, around 10 million<br />

households in Western Europe had<br />

to be disconnected from the grid<br />

within 19 seconds to prevent a<br />

pan-European blackout. This time,<br />

those affected were “only” large<br />

commercial customers in France<br />

and Italy which had contractually<br />

agreed to be disconnected should<br />

such an incident occur. The precautionary<br />

and communication<br />

measures of the 43 European transmission<br />

system operators, which<br />

have continually been improving<br />

the situation since 2006, meant the<br />

disruption could be rectified after<br />

about one hour. Hardly anybody<br />

had expected yet another major<br />

disruption. Despite everything,<br />

nobody knows whether the security<br />

mechanisms which have been<br />

designed will also be effective when<br />

the next incident takes place.<br />

The worst case would be a pan-<br />

European electricity, infrastructure<br />

and supply outage, a so-called<br />

blackout, as is expected by the<br />

Austrian Armed Forces or the<br />

author, within the next five years.<br />

In the European interconnected<br />

system, the expenditures needed to be<br />

able to maintain grid stability have<br />

been increasing <strong>for</strong> many years. The<br />

Austrian bottleneck management<br />

costs, i. e., the expenditures to avert<br />

an imminent blackout, have ballooned<br />

from 2 million euro in 2011 to<br />

346 million euro. Instead of 2 interventions,<br />

interventions were necessary<br />

on 301 days within a few years.<br />

Although these expenditures fell<br />

slightly in 2019 and 2020, they are<br />

still far too high. This is primarily<br />

down to the fact that the system does<br />

not adjust to the framework conditions,<br />

which have changed considerably<br />

in the meantime, and also<br />

the necessary transition to renewable<br />

energy.<br />

| Figure 1<br />

ENTSO-E/RG CE – Regional Group Central Europe.<br />

Lack of storage systems<br />

and buffers<br />

Wind and sun are not always available,<br />

and there are sometimes significant<br />

deviations between <strong>for</strong>ecast and<br />

actual production. In a system where<br />

the balance between generation and<br />

consumption has to be maintained <strong>for</strong><br />

31,536,000 seconds per year, this is<br />

an enormous challenge, particularly<br />

since there is a lack of systemsupporting<br />

storage systems and<br />

buffers. This situation can only be<br />

remedied by large-scale power station<br />

interventions, but this does not represent<br />

a permanent solution and incurs<br />

high costs. In addition, the susceptibility<br />

to failure of the whole system is<br />

increasing because it is permanently<br />

under stress.<br />

Whereas in Austria around<br />

3,300 GWh of pumped storage capacity<br />

is theoretically available, the<br />

whole of Germany can muster only<br />

around 40 GWh. And there are no<br />

plans <strong>for</strong> expansion which are worth<br />

mentioning. With electricity consumption<br />

currently at 60 to 80 GW,<br />

Germany would not be able to cover<br />

even one hour of its own electricity<br />

consumption. Quite apart from the<br />

fact that this would not be technically<br />

feasible, because only around 11 GW<br />

of bottleneck power is available. In the<br />

whole of Europe, storage systems with<br />

a turbine capacity of around 47 GW<br />

are currently available, two thirds of<br />

this with a pumping option to refill the<br />

29<br />


Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster ı Herbert Saurugg

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


storage reservoirs when surplus<br />

electricity is available. This can cover<br />

or temporarily store only a fraction of<br />

European consumption.<br />

The issue of storage ranges from<br />

inherent to seasonal, which requires<br />

different technologies. The transition<br />

to renewable energy so far has disregarded<br />

the fact that conventional<br />

power stations have the storage<br />

integrated in the primary energy<br />

( nuclear fuel rods, gas, coal, oil), thus<br />

making it possible to balance the<br />

continual changes in consumption.<br />

But now we have increasing, and<br />

increasingly more difficult to <strong>for</strong>ecast<br />

consumption, and volatile electricity<br />

generation at the same time. Two<br />

things which cannot be reconciled<br />

without appropriate storage systems<br />

and buffers.<br />

<strong>Power</strong>-to-X<br />

<strong>Power</strong>-to-X, especially the use of<br />

hydrogen, is deemed to be very<br />

promising <strong>for</strong> seasonal storage. In<br />

principle, it sounds very tempting,<br />

since an existing infrastructure would<br />

already be available - the gas grid. The<br />

fact that a number of big challenges<br />

remain to be solved is usually not<br />

mentioned. Least of all the costs. The<br />

announcement of a large wave of<br />

financial support triggered a goldrush<br />

mood and an avalanche of further<br />

announcements. It is to be expected<br />

that a gold nugget or two will indeed<br />

be found. But people should not really<br />

expect that a great breakthrough and<br />

widespread implementation will be<br />

possible within the next few years.<br />

What we do need are solutions that<br />

can be implemented rapidly, not only<br />

in 10 to 20 years’ time. On the other<br />

hand, we still know relatively little<br />

about the potential side effects of the<br />

water vapor which is released in huge<br />

amounts as the hydrogen is being<br />

reconverted to produce electricity.<br />

And even more attention needs to be<br />

paid to this aspect with the planned<br />

methanation, since we already know<br />

the effects here, because methane is<br />

significantly more harmful to the environment<br />

than CO 2 .<br />

Inconsistency<br />

The general principle is that there is<br />

no <strong>for</strong>m of energy which would not<br />

have any side effects. Enormous<br />

resources are required <strong>for</strong> wind and<br />

PV systems as well, but people usually<br />

have a distorted perception of this,<br />

un<strong>for</strong>tunately. The individual system<br />

is small and manageable. But if one<br />

considers the actual per<strong>for</strong>mance and<br />

extends these considerations to cover<br />

| Figure 2<br />

Turbo-generator set of a thermal power plant. (Source: Foro de la Industria <strong>Nuclear</strong> Española)<br />

a period of one year, a very different<br />

picture emerges. The wrong way of<br />

thinking often leads to apples being<br />

compared with oranges, or to average<br />

values being used. But all that is<br />

relevant <strong>for</strong> the operation is the<br />

contribution that one specific type of<br />

energy generation can guarantee in<br />

order to maintain the necessary<br />

permanent balance. This means not<br />

calculated as a statistical average over<br />

the year, but plannable, reliable and<br />

constant. If that were to be done, one<br />

would very quickly recognize that it<br />

requires much more than simply a<br />

production plant.<br />

This is precisely the way of thinking<br />

that is necessary to be able to ensure<br />

the systemic restructuring of our most<br />

important lifeline. Our either/or<br />

thinking will not get us anywhere<br />

here. We need both/and thinking to<br />

master the challenges we are facing.<br />

CO 2 emissions can be significantly<br />

reduced with renewable energies, but<br />

at the same time we also need other<br />

elements in the system to be able to<br />

continue to guarantee the very high<br />

security of supply to which we have<br />

hitherto been accustomed.<br />

Instantaneous reserve<br />

Another technical detail which is<br />

hardly ever considered concerns<br />

the instantaneous reserve, i.e., the<br />

rotating masses of conventional power<br />

stations. When nuclear and coal-fired<br />

power plants are shutdown, these<br />

reserves are also disconnected from<br />

the grid on a grand scale. The gyrating<br />

masses of the synchronous generators<br />

play a key role <strong>for</strong> the frequency<br />

generation and maintenance, since<br />

mechanical energy is thereby continuously<br />

converted into electrical<br />

energy and vice versa without the<br />

need <strong>for</strong> controlling interventions. A<br />

purely physical process. They can also<br />

be thought of as large shock absorbers<br />

<strong>for</strong> load shocks, which have so far<br />

ensured that the operation of the<br />

European interconnected system has<br />

been so stable. These shock absorbers<br />

are now being removed and not really<br />

replaced, which makes the whole<br />

system more susceptible to failure.<br />

The instantaneous reserve is at the<br />

same time also an inherently available<br />

energy storage system, which can<br />

temporarily buffer any short-term<br />

energy surplus. The generated frequency<br />

of the alternating current<br />

there<strong>for</strong>e also always indicates<br />

whether there is a lack of power or<br />

a surplus of power in the system overall.<br />

IT-independent control interventions<br />

can there<strong>for</strong>e be specifically<br />

per<strong>for</strong>med via the frequency, and the<br />

system overall kept stable.<br />

Implementation speed<br />

Approaches which utilize large<br />

system-supporting storage batteries<br />

and corresponding power electronics<br />

already exist, and are already being<br />

used in Southern Australia, Great<br />

Britain and now also in Texas, <strong>for</strong><br />

example, to reproduce and compensate<br />

the instantaneous reserve. It<br />

is supplementary, however, and will<br />

never be able to replace the complete<br />

instantaneous reserve. Here again, a<br />

both/and mindset is crucial. In the<br />

ENTSO-E RG CE grid, these systems<br />

first need to be implemented on a<br />

grand scale, however. As is often the<br />

case, the sticking point is not the<br />

knowledge or the technology, but the<br />

implementation. This would have to<br />

take place at the same speed as the<br />

other measures are being taken.<br />

Germany is going it alone<br />

The biggest problem is that Germany<br />

in particular is taking the second step<br />

be<strong>for</strong>e the first: Conventional power<br />

Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster ı Herbert Saurugg

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

stations are being shut down in<br />

large numbers without an equivalent<br />

replacement being available. The<br />

emphasis so far has been placed on<br />

the rapid expansion of wind and PV<br />

power stations or providing massive<br />

financial support <strong>for</strong> them. But what is<br />

missing here is the indispensable<br />

system adjustment, starting with the<br />

lack of storage systems and buffers,<br />

and continuing with the lack of<br />

trans mission possibilities, i.e., lines.<br />

In addition, the electricity no longer<br />

has to be distributed in a one-way<br />

system only, because those who<br />

were pre viously consumers have now<br />

increasingly become producers as<br />

well, i.e., so-called prosumers, and<br />

there<strong>for</strong>e there are also load flows in<br />

the opposite direction, <strong>for</strong> which the<br />

system and the protective devices<br />

were never designed.<br />

In Germany, it is also assumed, at<br />

least in the current planning documents,<br />

that in the future, electricity<br />

can simply be imported from its neighbors<br />

when needed. But somebody else<br />

might just have a thing or two to say<br />

about that. Because: Where is the<br />

electricity going to come from when<br />

these countries have already been<br />

importing electricity from Germany<br />

when they have had shortfalls? In<br />

addition, conventional power stations<br />

are being shutdown everywhere. And<br />

the idea that the wind will always be<br />

blowing somewhere is a myth which<br />

does not withstand scrutiny. Quite<br />

apart from the fact that the transmission<br />

infrastructure would still be<br />

needed, and this was never built <strong>for</strong><br />

large-scale electricity exchange. The<br />

desire <strong>for</strong> Europe to be a single<br />

conductive sheet of copper is understandable,<br />

but bears no resemblance<br />

to reality and ignores physical framework<br />

conditions.<br />

Decentralized functional units<br />

Moreover, millions of tiny power<br />

stations and new actors can no longer<br />

be controlled using the centralized<br />

structure and logic which has previously<br />

been successful. What is<br />

required instead is an “orchestration”<br />

of this multitude of components and<br />

actors which, with the self-organization<br />

of a “swarm”, will then automatically<br />

play their part in ensuring the<br />

security of supply by having a view of<br />

the situation in the overall system<br />

which is accessible to all. This requires<br />

it be restructured into so-called robust<br />

energy cells, however, since the increasing<br />

complexity will not be<br />

manageable otherwise. For complex<br />

systems cannot be centrally controlled,<br />

they require decentralized autonomous<br />

units, where demand, storage<br />

and generation are balanced locally or<br />

regionally if possible, and not as at<br />

present, where problems are shifted<br />

around across a wide area. Crosssystem<br />

synergies (electricity, heat,<br />

mobility) must be used as well. The<br />

issue is there<strong>for</strong>e a holistic energy<br />

supply in cellular structures, which<br />

first requires a rethink in many places.<br />

Such an approach is not inconsistent<br />

with the previous large-scale<br />

system, which will still be required as<br />

be<strong>for</strong>e, since it will not be possible to<br />

supply large consumers such as large<br />

industrial enterprises or cities in other<br />

ways <strong>for</strong> some time yet. But these<br />

decentralized structures and functional<br />

units do enable us to enhance<br />

the robustness of the overall system<br />

bottom-up and while it is in operation,<br />

without interruptions. Cellular structures<br />

are not as efficient as the largescale<br />

system we have had to date, but<br />

this holds true only as long as there is<br />

no major disruption in the <strong>for</strong>m of a<br />

blackout. In such a case, all previous<br />

gains in efficiency would be destroyed<br />

in a single blow and incredible societal<br />

damage would be caused. Resilience<br />

and robustness require redundancies<br />

and reserves, and are there<strong>for</strong>e generally<br />

in conflict with the efficiency<br />

mindset, which is driven mainly by<br />

economic considerations.<br />

No such thing as one-hundred<br />

percent security<br />

Moreover, there is simply no such<br />

thing as a failure-proof system, as the<br />

European transmission system operators<br />

stated clearly and unequivocally<br />

in their investigative report on the<br />

blackout in Turkey: “A large electric<br />

power system is the most complex<br />

existing man-made machine.<br />

Although the common expectation of<br />

the public in the economically<br />

advanced countries is that the electric<br />

supply should never be interrupted,<br />

there is, un<strong>for</strong>tunately, no collapsefree<br />

power system.”<br />

Increasing complexity<br />

We should there<strong>for</strong>e learn from<br />

nature, where all living things are<br />

organized in cellular structures. This<br />

has obviously been tried and tested<br />

and has survived through time. For<br />

what is being celebrated as a decentralized<br />

transition to renewable energy is<br />

currently anything but decentralized.<br />

The whole transition to renewable<br />

energy to date only works because of<br />

the existing centralized system with<br />

the requisite storage systems and<br />

buffers. The proposed smart grid and<br />

flexibilization measures also depend<br />

on a comprehensive, cen tralized IT<br />

network and thus on an increasing<br />

degree of complexity. Thus, in addition<br />

to the risk of cyber attacks, the<br />

result is additional, hardly noticed<br />

side effects.<br />

Complex systems<br />

Complex systems exhibit a number<br />

of unpleasant characteristics which<br />

cannot be managed with our linear<br />

way of thinking and machine logic<br />

which has succeeded so far. As the<br />

number of actors and the networking<br />

increases, so does the complexity and<br />

thus the dynamics, which we can<br />

observe on an ongoing basis, of<br />

course. We can hardly keep up. At the<br />

same time, the <strong>for</strong>ecastability of the<br />

system behavior worsens because<br />

self-amplifying feedback processes<br />

are possible, as can currently be seen<br />

with the phasing out of coal power: An<br />

increasing number of power plant<br />

operators want to abandon coal early,<br />

because their operation is no longer<br />

profitable. At the same time, we have<br />

more or less run down the overcapacities<br />

which used to be available<br />

during the past 10 years, which means<br />

less and less scope <strong>for</strong> action remains.<br />

Phase-out of coal and nuclear<br />

power<br />

At the beginning of January 2021,<br />

those German coal-fired power plants<br />

which had strictly speaking been<br />

selected <strong>for</strong> early shutdown had<br />

already to go onstream again, because<br />

the demand could not be covered<br />

sufficiently well. If Germany sticks to<br />

its plans to phase out coal and nuclear<br />

power, which is currently firmly<br />

scheduled <strong>for</strong> the end of 2022, this<br />

will already give rise to critical<br />

windows in the coming months,<br />

where regional shutdowns to protect<br />

the system as a whole can no longer be<br />

excluded. It is irrelevant here whether<br />

it will nevertheless just work out<br />

in 99.99 percent of the time. The<br />

electricity supply system knows no<br />

leeway here. The balance must be<br />

safeguarded 100 percent of the time.<br />

There is a risk the system will collapse<br />

otherwise.<br />

Lack of basic knowledge<br />

It is un<strong>for</strong>tunately the case that in<br />

many fields and among most of<br />

the decision-makers, too, there is a<br />

lack of the most basic knowledge<br />

about the laws of nature, especially<br />

the laws of physics, and also a lack<br />

of technical know-how to understand<br />


Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster ı Herbert Saurugg

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


the implications of often ill-considered<br />

decisions. This situation is now<br />

being compounded by the lack of<br />

knowledge on how to deal with<br />

complex systems, since this is not part<br />

of our universal basic education.<br />

Characteristics of complex<br />

systems<br />

One further characteristic of complex<br />

systems is that small causes can have<br />

massive effects, as we are currently<br />

experiencing with the coronavirus<br />

pandemic. A virus turns the whole<br />

world upside down in a matter of<br />

weeks. The consequences of decisions<br />

are frequently irreversible. A power<br />

plant which has been shut down,<br />

deconstructed, and decommissioned<br />

is lost <strong>for</strong>ever. It is very expensive to<br />

maintain and reactivate power plants<br />

which have been mothballed.<br />

Non-linearity means that many of<br />

our previous methods of risk assessment<br />

fail. The delayed consequences<br />

are particularly deceptive since people<br />

like to ignore them. They include, <strong>for</strong><br />

example, the 50.2 hertz problem,<br />

which arises when a large number of<br />

old installations with inverters disconnect<br />

from the electricity grid at the<br />

same time, leading to a yo-yo effect.<br />

This problem is supposed to have been<br />

solved, but we do not know whether<br />

this is actually the case. What we do<br />

know is that it was ignored <strong>for</strong> far too<br />

long. Neither is the effect immediately<br />

noticeable with the instantaneous<br />

reserve, or when power plants are<br />

being shutdown. Things mount up<br />

and there comes a point when something<br />

happens which is the last straw<br />

and can no longer be controlled –<br />

small cause, great effect. And there<br />

are no easy cause-and-effect relationships<br />

which can clearly be made to<br />

take the blame. Things have simply<br />

built up over a lengthy period of time.<br />

The collapse of complex systems is, as<br />

has been well investigated, not a fault<br />

but a system design characteristic to<br />

facilitate a renewal. Economic theory<br />

uses the term “creative destruction”.<br />

The new can often develop only when<br />

the old is broken or has been<br />

destroyed. If adopted with our most<br />

important lifeline, our electricity<br />

supply, it would equate to an intention<br />

to commit suicide.<br />

meanwhile between 40 and 50 years<br />

old. Some are even older. This means<br />

that far-reaching changes will have to<br />

be introduced in the next few years.<br />

But the currently purely economic<br />

considerations and the uncertain<br />

framework conditions mean this is not<br />

worthwhile. Postponing investments<br />

is thus a popular move, but one which<br />

increases the susceptibility to failure.<br />

And when investments are made only<br />

when it is worthwhile, it is already too<br />

late. This explains why the liberalized<br />

electricity market is also contributing<br />

to reducing the reserves and redundancies.<br />

What may be acceptable in<br />

other types of infrastructure could<br />

come to a nasty end if used <strong>for</strong> the<br />

vital electricity infrastructure, as is<br />

illustrated by the turkey illusion: A<br />

turkey which is fed every day by its<br />

owner assumes on the basis of its daily<br />

positive experience (being fed and<br />

looked after) that the owner only has<br />

its best interests at heart. It lacks the<br />

most important in<strong>for</strong>mation that this<br />

care serves only one purpose: On the<br />

day be<strong>for</strong>e Thanksgiving, traditionally<br />

the day on which the turkeys are<br />

slaughtered, it gets a fatal surprise.<br />

This metaphor comes into its own<br />

with very rare events which have<br />

enormous consequences, so-called<br />

extreme events (“X-Events”) or strategic<br />

shocks. In such cases, we like to<br />

mistake the absence of proof <strong>for</strong> the<br />

proof of absence.<br />

Extreme weather events<br />

As if this were not enough, we must<br />

also expect that extreme weather<br />

events will become more common in<br />

Europe just as they already are in<br />

Australia, Cali<strong>for</strong>nia or Texas. This<br />

also means we have to expect serious<br />

damage to infrastructures and infrastructure<br />

outages. The droughts of the<br />

last few years in particular have posed<br />

an enormous challenge <strong>for</strong> conventional<br />

power plants, which have to<br />

draw their cooling water from lakes<br />

and rivers. At the same time, falling<br />

water levels reduce the capacity of<br />

hydroelectric power plants. In the<br />

other extreme case, floods or torrential<br />

rainfall events cause problems<br />

with electricity generation, as<br />

happened in June 2020, <strong>for</strong> example,<br />

when a torrential rainfall event<br />

knocked out the biggest Polish coalfired<br />

power station and other generating<br />

plants at the same time, leading<br />

to a critical gap in supply.<br />

Energy cells are also affected in<br />

these situations, but the risk of sudden<br />

and widespread outages could be<br />

significantly reduced here. Cells do<br />

not have greater security of supply<br />

per se. But they do help to reduce<br />

the potential damage, and this is<br />

gaining in importance as a result of<br />

the problems illustrated. Moreover,<br />

we are still creating many even worse<br />

dependencies and hence vulnerabilities<br />

by developing a structure<br />

which increasingly lacks borders.<br />

Lack of predetermined<br />

breaking points<br />

The lack of clearly defined, predetermined<br />

breaking points makes it<br />

much more difficult to re-establish a<br />

network. And this is precisely the<br />

aspect that is to be extended even<br />

more in the next few years. An EU<br />

directive requires at least 70 percent<br />

of the capacity of the border interconnectors<br />

to be open <strong>for</strong> the crossborder<br />

electricity trade by 2025.<br />

Something which can boost competition<br />

and thus lower prices on the<br />

daily level leads on the other hand to a<br />

massive vulner ability of the whole<br />

system, because it means that less and<br />

less consideration is given to the<br />

physical limits. A possible inter ruption<br />

can spread much faster and much<br />

further. These directives are thus<br />

clearly at variance with a robust,<br />

cellular approach.<br />

Aging infrastructures<br />

The transition to renewable energy is<br />

not the only reason we are facing a<br />

time of great upheaval. The bulk of<br />

the infrastructure will reach the<br />

end of its service life over the next<br />

few years. Most power plants are<br />

| Figure 3<br />

Turkey Illusion.<br />

Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster ı Herbert Saurugg

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Dangerous trade in electricity<br />

The role played by the electricity trade<br />

is paid too little attention on the<br />

general level as well in respect of the<br />

risks to the European interconnected<br />

system. In June 2019, German<br />

electricity traders brought the system<br />

to the verge of collapse after they<br />

exploited a loophole in the regulations.<br />

Despite receiving a <strong>for</strong>mal<br />

warning and the prospect of high<br />

penalties which now loom, loopholes<br />

still seem to exist. In the first quarter<br />

of 2021, there have already been over<br />

60 frequency anomalies, which are<br />

probably caused by economically<br />

optimized power plant operational<br />

planning. In the whole of 2020 there<br />

were around 140 anomalies. The<br />

problem is: On the hour and regular as<br />

clockwork, half to two-thirds of the<br />

reserve which has been held back in<br />

order to be able to react to un<strong>for</strong>eseen<br />

power plant outages is “consumed”. If<br />

one or more power plant outages do<br />

actually occur during this time, which<br />

is more likely with the timetable<br />

change, this could rapidly lead to a<br />

further escalation. Although people<br />

have long been aware of the problem,<br />

the regulators do not seem to see the<br />

need to prevent this misuse. This can’t<br />

go on <strong>for</strong>ever.<br />

January 8, 2021<br />

There are also several indications that<br />

the two factors, the reduced instantaneous<br />

reserve and the excessive<br />

electricity trade, could have played a<br />

significant role in the major disruption<br />

on January 8, 2021, even if this has so<br />

far not been mentioned in any publicly<br />

available investigation reports.<br />

At 14:04 on January 8, a bus<br />

coupling was overloaded in the<br />

Ernestinovo (Croatia) trans<strong>for</strong>mer<br />

substation, which had then correctly<br />

shutdown <strong>for</strong> its own protection. This<br />

led to 13 other units in Southeast<br />

Europe being overloaded, causing the<br />

European interconnected system to be<br />

separated into two parts. The result<br />

was a massive increase in frequency to<br />

50.6 hertz in Southeast Europe caused<br />

by the massive power imbalance, and<br />

a drop in frequency to 49.74 hertz in<br />

Northwest Europe. In the Southeast<br />

there was excess power of 6.3 GW,<br />

which was simultaneously not available<br />

in the Northwest.<br />

The very steep drop or increase in<br />

frequency indicates that too little<br />

instantaneous reserve was available,<br />

which should have cushioned such a<br />

significant change in power. On the<br />

other hand, there was an enormous<br />

electricity transmission of approx.<br />

| Figure 4<br />

Phases of a pan-European electricity, infrastructure and supply outage (“blackout”).<br />

6.3 GW towards Spain and France at<br />

the same time. There are hence some<br />

indications that the transregional<br />

electricity trade could also have<br />

played a role here, and led to the overload.<br />

Another interesting point is that<br />

the bus coupling in the Ernestinovo<br />

trans<strong>for</strong>mer substation had not been<br />

classed as systemically important up<br />

to that point, and had there<strong>for</strong>e not<br />

been incorporated into the con tinuous<br />

safety calculations. This begs the<br />

question of how many such unnoticed<br />

breaking points could still exist. The<br />

incident on January 8, 2021 should<br />

there<strong>for</strong>e be understood as a warning<br />

to be taken very seriously, even<br />

though politicians immediately maintained<br />

that the electricity supply was<br />

secure. Thirty-six countries are all<br />

sitting in the same boat, and if it<br />

capsizes, they will all go down with it.<br />

After a blackout<br />

Austria is probably one of the first<br />

countries which will be in a position to<br />

re-establish a working power grid,<br />

although this could still take about<br />

one day or longer. It will take at least a<br />

week be<strong>for</strong>e electricity is flowing<br />

everywhere again on the European<br />

level. But that is not all.<br />

In general, the consequences and<br />

restart times after a widespread and<br />

sudden outage of the power supply<br />

are massively underestimated. Many<br />

preparatory measures deal only with<br />

the immediate provisions <strong>for</strong> the<br />

power outage, which usually leads to<br />

the procurement or extension of an<br />

emergency power supply. Albeit it that<br />

the outage phase is still the most<br />

manageable one. The considerably<br />

longer phases (phases 2 and 3) as<br />

systems are being restarted will have<br />

much more serious and catastrophic<br />

consequences in the other infrastructure<br />

sectors and during the<br />

resynchronization of the supply<br />

logistics, and this is something which<br />

is completely underestimated in<br />

this dimension because we have no<br />

experience of it.<br />

It is primarily the very high security<br />

of supply in all areas of our life, especially<br />

in Central Europe, which will<br />

backfire on us: There is a general lack<br />

of self-sufficiency measures or fallback<br />

solutions. Far too many people<br />

and organizations simply rely blindly<br />

on the continuous availability. A<br />

turkey illusion.<br />

Protracted restart<br />

It is thus to be expected, <strong>for</strong> example,<br />

that after the electricity supply<br />

resumes, it will be several more days<br />

be<strong>for</strong>e telecommunication services,<br />

i.e., cell phones, internet, and landlines,<br />

are back in operation, because<br />

serious hardware damage and overloads<br />

must be expected. This takes us<br />

to week 2 at least if we are lucky, until<br />

wide-scale production and goods distribution<br />

can start up again. This does<br />

not take account of the international<br />

intermeshing in the supply logistics.<br />

And neither the people nor companies<br />

nor countries are prepared <strong>for</strong> this.<br />

There is thus the threat of an inconceivable<br />

catastrophe, which could end<br />

in the biggest catastrophe after the<br />

Second World War.<br />

What can we do?<br />

In the short term, the only thing that<br />

will help is to prepare <strong>for</strong> the event,<br />

which means (in a general sense as<br />

well): Prevention and security are<br />

important, but not enough. There has<br />

to be both/and thinking here as well:<br />

We also have to be in a position to deal<br />

with unexpected events and get a grip<br />

on them. This applies at all levels. For<br />

example, preventing cyber attacks is<br />

enormously important, yet an IT<br />

recovery plan is indispensable, even if<br />

you always hope it will never be<br />

needed. But hope on its own is not<br />

enough. The same applies in relation<br />

to blackouts. We are currently undertaking<br />

the biggest infrastructure<br />

trans<strong>for</strong>mation of all times – as openheart<br />

surgery and without a safety<br />

net. It could turn out to be a fatal<br />

evolutionary mistake.<br />

The most important step begins<br />

within your own four walls: Be able to<br />

be completely self-sufficient <strong>for</strong> at<br />

least two weeks, looking after yourself<br />

and your family from your own<br />

pro visions and supplies. This means<br />


Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster ı Herbert Saurugg

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


2 liters of water per person per day.<br />

After the outage, you can cook again<br />

but it is not possible to go shopping. So<br />

have provisions such as pasta, rice,<br />

and tinned food <strong>for</strong> two weeks. The<br />

same applies to important medi cation,<br />

and food <strong>for</strong> small children and pets.<br />

Torches, a battery-powered radio,<br />

rubbish bags and other important<br />

articles that you might need. In other<br />

words, things you would take with<br />

you on a 2-week camping holiday.<br />

Very low level<br />

of preparedness<br />

Several investigations have shown<br />

that around a third of the population<br />

could be self-sufficient <strong>for</strong> a maximum<br />

of four days, and a further third <strong>for</strong> a<br />

maximum of seven days. This is the<br />

beginning of a vicious circle, because<br />

when people can no longer provide <strong>for</strong><br />

themselves to a sufficient degree, they<br />

do not come into work to power up the<br />

systems again. A vicious spiral is set in<br />

motion. This explains why broadbased<br />

self-sufficiency in the population<br />

is an essential prerequisite <strong>for</strong><br />

being able to cope with such a<br />

scenario. This especially also relates to<br />

those organizations and companies<br />

which must be able to maintain an<br />

emergency service in such an event,<br />

including the energy business.<br />

Stand-alone PV systems<br />

And many PV owners are not aware<br />

that their PV system will not supply<br />

any electricity either during the<br />

outage, because most systems are<br />

line-commutated. Only stand-alone<br />

PV systems, i.e., those supplemented<br />

with system decoupling, hybrid<br />

inverters, and storage devices, can<br />

maintain an emergency supply in their<br />

own four walls even in the event of an<br />

outage. So power could continue to be<br />

provided <strong>for</strong> lighting, heating, and<br />

the refrigerator/freezer (provisions!).<br />

This would noticeably lessen the<br />

impact of the scenario. From society’s<br />

point of view, it would be even more<br />

effective and more efficient to construct<br />

regional energy cells as rapidly<br />

as possible, thus ensuring that at least<br />

a basic emergency supply in respect<br />

of water, wastewater, heat or healthcare<br />

services could be maintained.<br />

even during an outage. This will<br />

not happen, however, because the<br />

necessary awareness and the<br />

requisite framework conditions are<br />

lacking.<br />

Organizational measures<br />

The organizational measures which<br />

are necessary can then build on these<br />

personal precautionary measures.<br />

This represents the first step towards<br />

sensitizing a company’s own staff by<br />

giving them a nudge to take their own<br />

precautions. On the other hand, full<br />

consideration is required as to how<br />

the necessary communication can be<br />

safeguarded in the event of a blackout.<br />

In many cases, only offline plans,<br />

i.e., prepared arrangements which<br />

have to be available in the minds of<br />

the staff, will work. Key staff have to<br />

know what to do when nobody else<br />

can be reached, and how the handover<br />

and supply operates when an<br />

emergency service has to be maintained.<br />

Raising the alarm in the usual<br />

way will generally not be possible<br />

because most of the telecommunication<br />

systems will go down within a<br />

few minutes of the power outage. As<br />

far as staff availability is concerned, it<br />

is primarily their personal circumstances,<br />

such as how far they have to<br />

travel to their place of work, or other<br />

obligations such as family members<br />

who need to be looked after, offices<br />

they hold in the local crisis management<br />

group or emergency response<br />

organizations, which need to be<br />

considered. Moreover, an assessment<br />

must be carried out as to how long the<br />

available resources, <strong>for</strong> example the<br />

fuel <strong>for</strong> emergency generators <strong>for</strong><br />

emergency operation, will last, since<br />

there is little hope of external supplies<br />

coming in if appropriate preparatory<br />

measures are not taken. This continues<br />

right through to restart plans,<br />

where consideration must be given as<br />

to the conditions which must prevail<br />

be<strong>for</strong>e it is even possible <strong>for</strong> regular<br />

operation to be resumed again.<br />

Summary<br />

The European electricity supply<br />

system is currently going through a<br />

time of radical upheaval, where the<br />

crux is: “Too many cooks spoil the<br />

broth.” This situation has arisen<br />

because there is no systemic overall<br />

coordination and approach. Each<br />

member country is transitioning to<br />

renewable energy in different directions,<br />

and a coordinated approach is<br />

difficult to discern. Furthermore,<br />

fundamental physical and technical<br />

framework conditions are being<br />

ignored and replaced with wishful<br />

thinking, and it is <strong>for</strong>eseeable that this<br />

can only lead to disaster. After all, the<br />

electricity supply system obeys only<br />

the laws of physics. We can still turn<br />

away from this disastrous route. This<br />

would require quick and decisive<br />

action, but there is no evidence of this<br />

at present.<br />

Author<br />

Herbert Saurugg<br />

President of the<br />

Austrian Society <strong>for</strong><br />

Crisis Preparedness<br />

(GfKV)<br />

office@saurugg.net<br />

Herbert Saurugg is an international blackout and crisis<br />

preparedness expert, President of the Austrian Society<br />

<strong>for</strong> Crisis Preparedness (GfKV), author of numerous<br />

specialized publications and a requested keynote<br />

speaker and interview partner on the topic of<br />

“A Europe-wide power, infrastructure and supply<br />

breakdown (‘blackout’)”. For the past 10 years, he<br />

has been researching the increasing complexity and<br />

vulnerability of vital infrastructures and possible<br />

solutions <strong>for</strong> making the supply of vital goods more<br />

robust again. At www.saurugg.net he runs an<br />

extensive expert blog on these topics.<br />

Energy Policy, Economy and Law<br />

Europe on the Road to a Major Disaster ı Herbert Saurugg

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

A Role <strong>for</strong> <strong>Nuclear</strong><br />

in the Future Dutch Energy Mix<br />

Findings of a Study <strong>for</strong> the Dutch Parliament<br />

Bojan Tomic and Mario van der Borst<br />

Introduction The EU is embarking on the European “Green Deal”, with the target to be “climate neutral” by 2050.<br />

With majority of EU greenhouse gas emissions coming from production and use of energy, all possible energy sources<br />

warrant a new look. Facing the need <strong>for</strong> a drastic reduction of CO 2 emissions over the next couple of decades, while<br />

having limited back up options <strong>for</strong> VREs a potential role of nuclear energy <strong>for</strong> the Netherlands in 2050 has been raised<br />

by the Dutch parliament. Among seven questions raised by the Dutch parliament (motion Yeşilgöz-Zegerius/Mulder<br />

(2018/2019 35167NR15) of specific interest were prospects and costs of new NPPs including SMRs, comparison with<br />

other sources of electricity also considering CO 2 costs as well as potential scenarios including nuclear that are possible<br />

<strong>for</strong> the Netherlands. Consideration of the security of supply, reliability, and flexibility as well as new development<br />

including hydrogen cycle were important. To respond to the parliamentary motion, the Ministry of Economic Affairs<br />

and Climate Policy of the Netherlands launched a “meta- study” to critically assess and compile in<strong>for</strong>mation from<br />

numerous reports while placing those in the specific Dutch perspective. Furthermore, the Study was to examine the cost<br />

of electricity from nuclear power plants and other low-carbon electricity sources specifically <strong>for</strong> the Netherlands.<br />

In their reports, most international<br />

organisations, from IPCC over US EIA,<br />

OECD NEA, WEC etc. favour deployment<br />

of nuclear to cope with climate<br />

change. Moreover, many see little<br />

chance of full decarbonisation without<br />

a significant contribution of nuclear.<br />

This is in particular so <strong>for</strong> the countries<br />

like the Netherlands where there are<br />

no other possibilities (except fossil) to<br />

complement the VRE (vari able renewable<br />

energy) sources. This highlights<br />

the need <strong>for</strong> a cost com parison that<br />

would not just be based on the headline<br />

LCOE (levelized costs of electricity)<br />

than rather consider all the cost<br />

drives, from the cost of financing a<br />

source of electricity over the operating<br />

costs including the system costs to the<br />

cost of decommissioning and waste. In<br />

this, the Study corrected some of<br />

previous cost comparisons that often<br />

excluded realistic system costs and/or<br />

other subsidies available to VREs such<br />

as grid connection, etc. Furthermore,<br />

the effects of the “priority access” to<br />

the grid were investigated. In particular,<br />

the notion of a “level playing<br />

field” was investigated, including<br />

sensitivity studies to account <strong>for</strong> uncertainties<br />

in some of the parameters.<br />

Upon its publication and presentation<br />

of the result in the Dutch<br />

Parliament a lively debate commenced,<br />

in the Chambers (and its committees)<br />

but also in the media and among the<br />

public. As expected, some of the<br />

particular strong reactions came from<br />

entities and interest groups representing<br />

the VREs, which claimed that ENCO<br />

study reached “wrong conclusion”,<br />

while falling to establish technically<br />

sound/justified arguments as what was<br />

wrong in ENCO Study’s conclusion.<br />

New nuclear power –<br />

where do we stand<br />

As of May 2020, 441 nuclear reactors<br />

are operating in 31 countries, with<br />

389,994 MWe total installed capacity.<br />

Further 54 nuclear power reactors are<br />

under construction, with a total of<br />

57,444 MWe total net installed capacity.<br />

Developing nations with increasing<br />

energy needs and those<br />

heavily relying on coal (e.g. China and<br />

India) are leading the way in ad vancing<br />

nuclear construction, based on own<br />

and <strong>for</strong>eign technologies. Per IAEA,<br />

about 19 countries are starting or<br />

planning construction, and even countries<br />

that have never employed nuclear<br />

as an energy source, are reviewing<br />

their position (e.g. Australian Parliament’s<br />

report). The world nuclear fleet<br />

generated 2,563 terawatt- hours (TWh)<br />

of electricity in 2018, a 2.4 percent<br />

increase over the previous year, which<br />

was essentially due to China’s nuclear<br />

output increasing by 44 TWh (+19 %),<br />

but still 4 percent below the historic<br />

peak of 2006.<br />

At the end of 2019, nuclear<br />

electricity constituted about 26 % of<br />

the EU’s electricity generation. There<br />

are 126 nuclear power plants. There<br />

are active constructions of new NPPs<br />

in 3 EU Member states, and up to<br />

6 MS are pursuing nuclear new built,<br />

of which Hungary expected to issue<br />

a construction licence <strong>for</strong> a new<br />

NPP in 2021. Regardless of massive<br />

investment in the VRE resources all<br />

across the EU, nuclear energy<br />

remains by far the largest (26.7 % in<br />

2019) single source of low-carbon<br />

energy in the EU, ahead of hydro<br />

(12.3 %), wind (13.3 %), and solar<br />

(4.4 %).<br />

As a possible contributor to the<br />

carbon-neutral future, small modular<br />

reactors (SMR) are receiving increased<br />

attention. This is due to the<br />

technological capability of nuclear<br />

to deliver on-demand electricity,<br />

coupled with a promise <strong>for</strong> great<br />

simplification and related cost reduction<br />

while applying industrial manufacturing<br />

and construction technologies<br />

at a factory rather than on site.<br />

The SMRs are expected to address the<br />

biggest obstacle <strong>for</strong> large nuclear<br />

power plants: long construction<br />

periods causing high capital costs.<br />

Active licensing activities with sites<br />

elected are underway in USA and<br />

Canada. Several EU countries expressed<br />

interest and as per news<br />

bulletins, some including Estonia and<br />

Poland started the negotiations with<br />

potential suppliers of SMRs.<br />

One of the typical complaints<br />

regarding nuclear power is that it is<br />

unsafe. To the wider public, when<br />

considering with wide media coverage<br />

and public interest related with any<br />

nuclear accidents, and in particular<br />

Chernobyl and Fukushima, such a<br />

perception is understandable. However,<br />

the fact of the matter is that no<br />

one died from the radioactivity<br />

released during Fukushima accident<br />

(and as per UNSECAR report released<br />

on 21st March 2021 “Radiation-linked<br />

increases in cancer rates not expected<br />

to be seen”). As per multiple<br />

studies undertaken on the Chernobyl<br />

accident and its consequences,<br />

apart from several dozens of first<br />

re sponders who died shortly after the<br />

accident, there was a very limited<br />

number of deaths caused by the radioactive<br />

release. To put safety in the<br />


Energy Policy, Economy and Law<br />

A Role <strong>for</strong> <strong>Nuclear</strong> in the Future Dutch Energy Mix ı Bojan Tomic and Mario van der Borst

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


| Figure 1<br />

Fatalities per TW of electricity generated <strong>for</strong> various sources.<br />

perspective it is useful to assess the<br />

fatalities per unit of generated energy<br />

from various sources of electricity.<br />

The fatalities caused by the nuclear<br />

industry in Figure 1 reflect the GEN II<br />

nuclear plants. Integral to the GEN III<br />

and SMR reactors is the fundamental<br />

design requirement of a strict limit to<br />

any radiological release in a case of<br />

accident. GEN III nuclear plants as<br />

well as most SMRs are designed to be<br />

“inherently safe”, meaning minimisation<br />

of probability of accidents and<br />

exclusion of off-site consequences<br />

even in cases where a hypothetical<br />

accident is to occur. Deployment of<br />

such reactors would enable the construction<br />

also in highly populated<br />

countries, without concerns of the<br />

population in the vicinity of a plant.<br />

This applies even more to future GEN<br />

IV reactors, where innovative and/or<br />

revolutionary concepts might be<br />

expected to lead to fully inherently<br />

safe designs.<br />

With that consideration, the notion<br />

of nuclear not being safe does not pass<br />

the scientific scrutiny. The energy that<br />

could have been produced in nuclear<br />

plants in Germany and instead was<br />

produced by burning coal, lignite and<br />

gas, affected the population and even<br />

much more the climate (in 2018<br />

German CO 2 emission per capita was<br />

almost double of that in France or the<br />

UK) not just in Germany but also in<br />

the neighbouring countries.<br />

Another criticism of nuclear power<br />

is that it generates radioactive waste<br />

that will remain dangerous <strong>for</strong><br />

millions of years to come. While<br />

notionally true, it is also well known<br />

and often ignored that the amount<br />

of waste that remain dangerous <strong>for</strong><br />

extended period of time is extremely<br />

small. Every other source of energy,<br />

even VREs generates waste that<br />

is dangerous to people and the<br />

environment and would need to be<br />

safely isolated, in quantities that are<br />

(much) larger than the radioactive<br />

waste generated in nuclear plants.<br />

Important advances have been<br />

achieved in the management of longlived<br />

high-level radioactive waste.<br />

Disposal in special canisters in geologically<br />

stable layers in the deep underground<br />

is inter nationally regarded<br />

as a safe solution. Pragmaticallygoverned<br />

countries, in particular the<br />

EU Member states in Scandinavia,<br />

implemented solutions <strong>for</strong> long-lived<br />

waste that guarantees no effect to the<br />

public and environment <strong>for</strong> much<br />

longer periods that the humankind<br />

exist on the Earth. It is useful to put<br />

that in the perspective of currently<br />

non-recyclable PV panels, or ever<br />

increasing needs <strong>for</strong> exotic material<br />

including rare earth, cadmium or<br />

lithium, mining and processing of<br />

which leave enormous impact on<br />

the environment and its residues<br />

entering the water supply affecting<br />

the world’s population today. Furthermore,<br />

unlike any other sources of<br />

electricity, nuclear has from the very<br />

beginning been planned to require<br />

plant operators to make a provision<br />

<strong>for</strong> decommissioning and <strong>for</strong> disposing<br />

of any waste, thus these costs<br />

are ‘ internalised’ as part of operating<br />

costs. No other source of electricity in<br />

the use today fully operates on such a<br />

principle.<br />

Societal costs of nuclear<br />

Every source of electricity (or indeed<br />

practically any other human activity)<br />

has external impact that are not fully<br />

reflected in the price, but which<br />

society as a whole must bear. The best<br />

example is the cost of emissions,<br />

which may (and in reality already is)<br />

cause damage to those who are<br />

not related nor benefitting from the<br />

activities. In the case of electricity<br />

generation, the external costs of<br />

interest are those related with three<br />

components: emissions of CO 2 and<br />

resulting climate change; damage/<br />

impact such as on health and crops<br />

associated with air, water or environmental<br />

pollutants and other nonenvironmental<br />

social costs.<br />

External costs to the society from<br />

the operation of nuclear power could<br />

assumed to be negligible as there are<br />

no emissions from the operation, and<br />

the cost of management of waste<br />

and decommissioning are internalised,<br />

meaning included in the price.<br />

Nevertheless, one might argue that a<br />

serious accident causing damage<br />

which is beyond the insurance limit<br />

might become the societal costs. However,<br />

<strong>for</strong> modern nuclear plants the<br />

probability of such an accident is<br />

extremely low and societal costs might<br />

be expected not to exist <strong>for</strong> the Gen III<br />

or inherently safe SMRs.<br />

Electricity generation from fossil<br />

fuels is not regulated in the same way,<br />

and there<strong>for</strong>e the operators of thermal<br />

power plants do not to internalise the<br />

costs of greenhouse gas emission or of<br />

releases in the atmosphere. In some<br />

countries this is being addressed<br />

through the CO 2 pricing. For VREs the<br />

impact of the decommissioning and<br />

waste management are not even<br />

known, effectively making the future<br />

societal cost.<br />

Externalities of electricity production<br />

are not limited to environmental<br />

and health related impact, but may be<br />

related with macro-economic, policy<br />

or strategic factors not reflected in<br />

market prices, such as security of<br />

supply, cost stability and broad economic<br />

impacts including employment.<br />

Although those externalities generally<br />

have not been subjected to systematic<br />

assessment and comparison, some<br />

qualitative analysis established high<br />

advantage <strong>for</strong> nuclear as compared<br />

with any other sources of electricity<br />

on the majority of the parameters of<br />

interest.<br />

One further aspect <strong>for</strong> consideration<br />

is in relation to the social impact<br />

is the land utilisation. For this aspect,<br />

the extremely high energy density of<br />

nuclear (up to about a 1000 times) is a<br />

great benefit compared to VREs. Due<br />

to its low energy density, VREs require<br />

lots of space. This is particularly<br />

relevant <strong>for</strong> solar PVs, where the<br />

installations are competing with land<br />

available <strong>for</strong> agriculture and/or<br />

encroaching the preserved nature,<br />

and <strong>for</strong> onshore wind, where increased<br />

opposition due to noise (on<br />

Energy Policy, Economy and Law<br />

A Role <strong>for</strong> <strong>Nuclear</strong> in the Future Dutch Energy Mix ı Bojan Tomic and Mario van der Borst

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

| Figure 2<br />

The cost breakdown <strong>for</strong> Hinkley point C NPP.<br />

shorter distance), drop shadow and<br />

intrusions into natural settings is<br />

becoming omnipresent.<br />

Especially in densely populated<br />

parts of Europe, such as the Netherlands,<br />

enormous needs <strong>for</strong> space <strong>for</strong><br />

some of the technologies is becoming<br />

increasingly a limiting factor in the<br />

deployment. Further to this, the<br />

disturbance of the landscape complains<br />

are on the raise everywhere.<br />

Although the “NIMBY” phenomena<br />

affects any intervention, a much<br />

higher energy density of nuclear<br />

plants, the number of people affected<br />

is only a fraction of those affected by<br />

the low energy density VREs.<br />

The cost of nuclear power<br />

Often raised drawback <strong>for</strong> nuclear<br />

power is that it is just “too expensive”.<br />

Clearly, judging from the headline<br />

numbers, e.g. the price of two large<br />

GEN III nuclear units under construction<br />

at Hinkley point in the UK is<br />

above 24 billion Euros, or multiple<br />

costs increases <strong>for</strong> similar units in<br />

France (Flamanville 3) or Finland<br />

(Olkilouto 3), the cost are very high.<br />

Furthermore, many were astonished<br />

with so called” strike price” <strong>for</strong> the<br />

electricity from Hinkley point C being<br />

94 GBP per MWhr when comparing<br />

that with currently traded price of<br />

about 50 to 60 GBP MWhr. However,<br />

the comparison with the strike price of<br />

about 140 GBP per MWhr <strong>for</strong> nondispatchable<br />

offshore wind sources provides<br />

a bit of perspective. To assess the<br />

cost of nuclear it is important to understand<br />

its background. The cost comparison<br />

with other sources using the<br />

“levelized cost of electricity” (LCOE)<br />

provide interesting insights.<br />

The construction of a nuclear plant<br />

is a large and extremely complex<br />

undertaking. While at the time of the<br />

most intensive deployment of nuclear<br />

plants in late seventies and eighties of<br />

the last century, typical construction<br />

period was in the order of 5 or so years.<br />

| Figure 3<br />

Cost of nuclear electricity in relation with WACC.<br />

With fewer nuclear plants being<br />

built nowadays, the construction duration<br />

extended dramatically, beyond<br />

15 years and counting <strong>for</strong> the EPR<br />

reactors in Finland and France. Given<br />

the high costs of a plant itself, just the<br />

cost of deployed capital over such a<br />

long period significantly contributes to<br />

the overall cost. How ever, this is not<br />

unique to nuclear plants. Other large<br />

and complex infrastructure projects<br />

experienced similar extension of the<br />

construction periods and resulting<br />

effects on the costs, e.g. an airport<br />

(BER, a factor of 3 cost increase) or a<br />

railway (Crossrail, factor of 3.5 cost<br />

increase and counting). The difference<br />

to those is in the financing costs.<br />

The cost of capital<br />

Where the nuclear plants are really<br />

penalised, and which is the dominant<br />

cause of their high price, is the costs<br />

of the capital. While infrastructure<br />

projects such as BER and Crossrail<br />

attract the capital with very low costs,<br />

due to a perceived risk related to<br />

nuclear projects, the cost of capital<br />

encompasses a risk premium. In<br />

the costs profile of new nuclear the<br />

majority is indeed the costs of capital,<br />

i.e. interest and risk premium. For<br />

Hinkley point C, about 65 % of the<br />

total cost of the plant is associated<br />

with interest payment.<br />

It is obvious that with the cost of<br />

capital as it is in the EU today (zero or<br />

negative interest rates), an investment<br />

model where two thirds of the cost is<br />

to cover the interest is not sustainable.<br />

With the weighted cost of the capital<br />

(WACC) in the range of 4 %, simular<br />

to what is used in VRE projects,<br />

nuclear becomes fully cost com petitive<br />

with other sources of carbon free<br />

electricity.<br />

The system cost<br />

Apart from the costs of investment<br />

(construction) and operating costs<br />

(fuel, operation, maintenance) various<br />

| Figure 4<br />

The contributors to cost of electricity, comparison between<br />

nuclear, solar and wind.<br />

energy technologies would have<br />

specific costs related to the integration<br />

into the electricity supply system. The<br />

system costs typically include the<br />

balancing costs (deviations from the<br />

planned production and extra cost <strong>for</strong><br />

investment in reserves), the profile<br />

cost (technology dependant, i.e.<br />

anti- cyclicals able to achieve higher<br />

prices) and the grid cost (extra cost of<br />


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<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


expanding the grid). The system costs<br />

are highly dependent on the configuration<br />

of the electrical system – the<br />

energy mix. The system costs is<br />

what differentiate between reliably<br />

dispatchable energy sources being<br />

able to supply agreed electricity to the<br />

grid and non-dispatchable ones, being<br />

dependant on external influences like<br />

weather and there<strong>for</strong>e requiring<br />

backups. For the VREs, the system<br />

costs are also dramatically increasing<br />

with the penetration, while dispatchable<br />

technologies might be credited<br />

with system benefits due to being able<br />

to vary their outputs to support system<br />

stability.<br />

The further point of attention is the<br />

electric potential (in installed MW)<br />

that is needed to guarantee the supply<br />

of electricity in dispatched MWh. This<br />

is best explained by comparing solar<br />

and nuclear. Because of the capacity<br />

factor of about 10 % <strong>for</strong> solar and<br />

90 % <strong>for</strong> nuclear, the installed capacity<br />

<strong>for</strong> solar to generate the same<br />

amount of electricity needs to be<br />

9 times larger. The LCOE cost calculation<br />

takes this into the account only as<br />

far as the expected production of<br />

electricity from different sources is<br />

concerned (i.e. capacity factor). However,<br />

the grid costs and in particular<br />

the balancing and profile costs to<br />

assure reliable supply of electricity,<br />

are (much) higher <strong>for</strong> VRE, and<br />

dramatically increasing with the<br />

higher penetration. The system costs<br />

strongly depends on the geography<br />

i.e. whether large hydro is available.<br />

Typical studies addressing the system<br />

costs always take into the account a<br />

certain proportion of hydraulic plants,<br />

which is not the case in countries such<br />

as the Netherlands.<br />

Another important consideration is<br />

that the deployment of a large share of<br />

variable-electricity generating sources<br />

with (nearly) zero marginal cost has a<br />

profound impact on the functioning of<br />

electricity markets and on the operation<br />

of the generating capacity. In the<br />

short term, reduced load factors (the<br />

compression effect) and lower prices<br />

| Figure 5<br />

The relation of system cost to the penetration of VREs.<br />

affect the economics of all dispatchable<br />

generators. Above certain level of<br />

penetration of VRE and at specific<br />

weather conditions, there would be<br />

no other generators on the market,<br />

leading to a necessity of shutting<br />

down some of the VRE producers. At<br />

that time the implicit promise (i.e. the<br />

state guarantee) that all electricity<br />

that would be generated by VREs will<br />

be taken by the grid and delivered to<br />

the consumers suddenly disappears,<br />

further increasing system cost but<br />

also the LCOE due to lower overall<br />

utilisation.<br />

The system costs <strong>for</strong> the dispatchable<br />

sources such as nuclear or coal/<br />

gas are very small, in the order of<br />

2 Euro/MWh. With a low penetration<br />

of VRE, the system costs remain small,<br />

as there are enough reserves to<br />

balance the grid when VREs are not<br />

generating. With an increased penetration<br />

of VRE, and in particular above<br />

about 50 %, the system costs become a<br />

dominant contributor, as documented<br />

in the research of the IEA in the<br />

Figure 5.<br />

The decarbonation of electricity<br />

supply with VRE only leads to the<br />

situation of both very high costs (due<br />

to electric potential, needs <strong>for</strong> grid<br />

development, etc.) AND accepting<br />

regular blackouts as there will be<br />

periods when none of the VREs would<br />

generate electricity. Availability of<br />

VREs is internally closely related, i.e.<br />

non redundant: doubling the amount<br />

of PV panels will not add to overnight<br />

supply; all windmills would stand still<br />

when there is no wind.<br />

The studies analysing VRE role in<br />

the electric supply often significantly<br />

underestimate system cost by projecting<br />

upwards from the current situation<br />

where there is 10-20 % penetration.<br />

Sometimes the “low” system<br />

costs are justified with the assumption<br />

that electricity will be unavailable <strong>for</strong><br />

certain amount of time, which is very<br />

likely not acceptable to today’s society.<br />

Furthermore, typically advertised<br />

“low cost of VRE” often exclude the<br />

grid connection cost, which in a case<br />

of offshore wind becoming a dominant<br />

contributor. On the contrary,<br />

nuclear is constantly dispatchable,<br />

able to balance the grid and its investment<br />

costs already include the grid<br />

connection.<br />

It should be highlighted that some<br />

nuclear plants are now being approved<br />

to operate <strong>for</strong> 80 years, while the wind<br />

generators and solar panels have projected<br />

lifetime up to a maximum of<br />

25 years (with discernible degradation<br />

over the lifetime <strong>for</strong> solar PV).<br />

Typically, after about 25 years, the<br />

investment in a nuclear plant is<br />

already paid off. For VRE, this is<br />

exactly the time when the new investment<br />

cycle is needed.<br />

The LCOE estimates <strong>for</strong> the<br />

Netherlands <strong>for</strong> the year 2040<br />

The key request by the Ministry of<br />

Economic Affairs and Climate Policy<br />

was to estimate the LCOE <strong>for</strong> several<br />

electricity generation technologies<br />

<strong>for</strong> the year 2040, on a comparable<br />

basis specifically <strong>for</strong> the Netherlands.<br />

The study considered the following<br />

emission free sources of electricity:<br />

p Large nuclear GEN-III plant<br />

p <strong>Nuclear</strong> SMR<br />

p Off-shore wind<br />

p On-shore wind<br />

p Large solar PV<br />

p Hydrogen <strong>Power</strong><br />

To make this comparison meaningful<br />

with expected higher (50 %) penetration<br />

of VREs, the adjusted “LCOE*”<br />

was calculated to include the system<br />

effects, as defined by the OECD NEA.<br />

A full utilisation was assumed <strong>for</strong><br />

all sources of electricity, meaning that<br />

each source would be allowed to<br />

deliver to the grid when it is capable to<br />

deliver, independent of electricityexchange-market<br />

or other prioritization<br />

mechanisms. For the stability of<br />

the electrical grid with the higher VRE<br />

penetration rates, VRE units would<br />

also be obliged to shut down or reduce<br />

the output at certain moments, like<br />

now is the case with the dispatchable<br />

plants. This will result in the utilisation<br />

rates being lower than 100 %. As<br />

those are not driven only by economic<br />

considerations, rather by political and<br />

other issues, the Study did not elaborate<br />

further on the expected utilisation<br />

rate. The basis assumption <strong>for</strong> the<br />

assessment is included in the list in<br />

the following table.<br />

The findings could be best illustrated<br />

by the summary Figure 6.<br />

The results are pretty obvious:<br />

even limiting the VRE penetration rate<br />

to 50 %, the system costs became so<br />

dominant that the dispatchable sources<br />

are visibly cheaper than the VREs.<br />

Compared with the offshore wind,<br />

onshore wind and solar PV, two<br />

nuclear options remain cheaper when<br />

realistic system costs are considered in<br />

the LCOE*. The Hydrogen Round trip<br />

is very costly. The expla nation is in the<br />

low efficiency, between 25 % and<br />

39 % <strong>for</strong> the electrolyser and the<br />

turbine, meaning that 60 % to 75 % of<br />

the energy is lost in the process. The<br />

hydrogen storage is assumed to<br />

be in the salt-caverns. When storage<br />

Energy Policy, Economy and Law<br />

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<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

in high pressure casks is selected, the<br />

LCOE* <strong>for</strong> this option could be 5-10<br />

times higher.<br />

As with any prediction <strong>for</strong> the<br />

future in a dynamic and changing<br />

environment, the point values might<br />

be far off if the assumptions change.<br />

All such estimations, and in particular<br />

those that are addressing the more<br />

distant future, could only be made on<br />

the basis of a set of assumptions, covering<br />

wide range of issues, from the<br />

technology development to the cost of<br />

financing and learning curves. While<br />

the projections of the LCOE* are considered<br />

the best estimate, it was highly<br />

interesting to assess how those estimates<br />

would be influenced by changes<br />

in the assumptions and/or relevant<br />

parameters. The Study undertook a<br />

series of sensitivity analysis, covering<br />

the following:<br />

p Construction times (duration)<br />

p Learning effects consideration<br />

p Impact of the lifetime of a plant<br />

p Utilisation rates of a plant<br />

p Interest-rate (WACC) sensitivity<br />

p System costs sensitivity<br />

p Sensitivity cases <strong>for</strong> hydrogen<br />

utilisation<br />

The results are depicted in the<br />

Figure 7, indicating the effects of<br />

uncertainties.<br />

The example sensitivity case <strong>for</strong><br />

the VRE penetration rate of 75 %<br />

shows an interesting correlation. The<br />

increased penetration of VREs from<br />

about 50 % to about 75 % leads to<br />

approximately doubling of the system<br />

costs <strong>for</strong> every technology. However,<br />

<strong>for</strong> the technologies with lower system<br />

costs, this effect is barely visible while<br />

<strong>for</strong> the non-dispatchable sources of<br />

electricity it dominates, as in the<br />

Figure 8.<br />

ENCO report caused quite a<br />

stir in the Dutch media and<br />

politics<br />

The prevailing public opinion in the<br />

Netherlands is that nuclear indeed<br />

contributes to lowering the emissions,<br />

but that the costs would be many<br />

times higher than solar and wind<br />

energy. Reference is often made to the<br />

cost overruns of the new construction<br />

projects in Finland and France. As a<br />

result, enthusiasm <strong>for</strong> nuclear energy<br />

decreased even among the most<br />

interested parties.<br />

The ENCO report made it clear that<br />

nuclear energy can compete with<br />

solar and wind energy in the future, if<br />

the system costs are allocated to the<br />

energy source causing those. This<br />

message did not please the renewable<br />

energy interests and many articles<br />

General assumptions<br />

LCOE assessment <strong>Nuclear</strong> VRE<br />

WACC 7 % 4,3 % 4,3 %<br />

| Table 1<br />

The relation of system cost to the penetration of VREs.<br />

appeared in the media contradicting<br />

the Study conclusions. Most of the<br />

articles lacked factual arguments and<br />

attempts were made to discredit the<br />

authors of the ENCO report.<br />

The consultancy firm Kalavasta,<br />

which had previously published a<br />

report on the “Costs of <strong>Nuclear</strong><br />

Energy”, wrote a negative assessment<br />

report, mainly focusing on the fact<br />

that” system costs are not that high”.<br />

The conclusion and arguments used<br />

have been thoroughly refuted by the<br />

Dutch journal Kernvisie.<br />

Reflecting Kalvasta criticism of the<br />

ENCO report, questions were asked in<br />

the Dutch parliament. The Parliamentary<br />

committee organised a round<br />

table discussion on December 2 nd<br />

2020 attended by the members of<br />

the Parliament and a variety of<br />

experts from energy companies,<br />

NGOs, consultancies and universities.<br />

Unsurprisingly, this discussion ended<br />

in a draw.<br />

In the meantime, EPZ, the operator<br />

of the nuclear power plant Borssele,<br />

announced that it is preparing the<br />

extension of its lifetime after 2033<br />

and consideration <strong>for</strong> the expansion<br />

of Borssele site with two new large<br />

nuclear power plants. Several Dutch<br />

provinces, such as Zeeland and<br />

Brabant, do not rule out nuclear<br />

energy as a solution <strong>for</strong> achieving a<br />

100 % CO 2 neutral economy by 2050.<br />

On March 17 th the elections <strong>for</strong> the<br />

Dutch parliament took place. <strong>Nuclear</strong><br />

energy was one of the major discussion<br />

topics during the campaign,<br />

including the argument that there is<br />

not sufficient space in the Netherlands<br />

to rely on wind and solar energy<br />

<strong>for</strong> decarbonisation. The opponents<br />

claiming that nuclear energy is too<br />

expensive. The political parties that<br />

believe in a role <strong>for</strong> nuclear energy to<br />

tackle the climate problem represent<br />

the majority in the new Dutch<br />

| Figure 6<br />

LCOE* <strong>for</strong> the decarbonised generation <strong>for</strong> the Netherlands in 2040.<br />

| Figure 7<br />

The results of sensitivity analysis on the LCOE*.<br />

Hydrogen<br />

P2P<br />

Technical Lifetime (years) 60 25 20, electrolysers limiting<br />

Depreciation period technical lifetime technical lifetime technical lifetime<br />

Utilisation factor 100 % 100 % 50 %<br />

Decommissioning costs<br />

Waste costs<br />

15 % of capital costs,<br />

discounted at 3 %<br />

Spent fuel dis posal and<br />

storage, decomm. waste<br />

included in decomm. costs<br />

and operational waste in<br />

O&M costs<br />

5% of capital costs,<br />

discounted at 3 %<br />

Decommissioning waste<br />

included in decomm.<br />

costs and operational<br />

waste in O&M costs<br />

5% of capital costs,<br />

discounted at 3 %<br />

Decommissioning. waste<br />

included in decomm.<br />

costs and operational<br />

waste in O&M costs<br />

Construction time (years) 7 0,5 – 1,5 3, CCGT limiting<br />

| Figure 8<br />

The results of sensitivity analysis on the LCOE*.<br />


Energy Policy, Economy and Law<br />

A Role <strong>for</strong> <strong>Nuclear</strong> in the Future Dutch Energy Mix ı Bojan Tomic and Mario van der Borst

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


parliament (80 out of 150 seats). It is<br />

expected that the nuclear option will<br />

be the topic <strong>for</strong> the Dutch political<br />

discussions <strong>for</strong> the coming years.<br />

From financial standpoint it is<br />

recognized that system costs are<br />

the discriminating factor between<br />

nuclear and the VRE. Numerous<br />

institutes, including PBL, TNO but<br />

also Berenschot/Kalavasta, involved<br />

in the development of the Dutch<br />

energy scenario studies all consider<br />

system costs in their analysis. However,<br />

the system costs as projected <strong>for</strong><br />

VRE are (by far) too optimistic and<br />

systema tically fail to consider obvious<br />

uncertainties. The extrapolation from<br />

the present situation to the one where<br />

VREs predominate is obviously impossible,<br />

because in the present world<br />

the VRE caused system costs are<br />

absorbed by the still-available margins<br />

in the electrical system. Some studies<br />

consider arrangements to moderate<br />

system cost including smart grids,<br />

load rejection, car-loading systems<br />

and decentralised generation enable<br />

short transport trajectories. All these<br />

solutions have their limitations and<br />

many are not established and their<br />

technical merits and general acceptance<br />

is uncertain. Furthermore, zero<br />

curtailment (100 % utilisation) is<br />

assumed <strong>for</strong> the VRE, and 50 % to<br />

70 % curtailment <strong>for</strong> nuclear. With<br />

higher VRE penetration this becomes<br />

impossible and furthermore it obviously<br />

does not establish a level playing<br />

field, where all CO 2 free generators<br />

should have the same priority to the<br />

grid.<br />

Conclusions<br />

The outcome of the Study <strong>for</strong> the<br />

Netherlands lead to some interesting<br />

insights. When the system costs are<br />

properly accounted <strong>for</strong>, two nuclear<br />

options are markedly cheaper than<br />

the offshore wind and significantly<br />

cheaper than photovoltaic. This is<br />

even be<strong>for</strong>e other (positive) externalities<br />

are considered, e.g. the lifetime<br />

of nuclear plants being 60 or<br />

even 80 years, while the VREs at best<br />

last <strong>for</strong> 25 years, the spatial impact of<br />

nuclear is a minuscule fraction of that<br />

<strong>for</strong> the VREs, or that the cost of<br />

nuclear already include provisions <strong>for</strong><br />

decommissioning and safe disposals<br />

of all of its waste.<br />

The positive vision on future<br />

developments is affecting all technologies,<br />

though mainly the offshore<br />

wind and nuclear SMR. For large<br />

nuclear significant saving could be<br />

achieved by reducing the duration<br />

of the construction; it is however<br />

uncertain whether nuclear industry<br />

would be able to erect a NPP in Europe<br />

in less than 7 years. A much more<br />

dramatic impact is observed with the<br />

reduction of the capital costs <strong>for</strong> a<br />

nuclear plant. When the WACC is<br />

reduced from 7 % to 4,3 %, the<br />

resulting decrease of LCOE* is around<br />

25 %. With some EU governments<br />

being able to borrow at negative rates,<br />

low WACC <strong>for</strong> nuclear by implementing<br />

risk- sharing instruments becomes<br />

a pretty logical con sideration.<br />

When the design lifetime of nuclear<br />

plant is being extended from 60 to<br />

80 years, the impact of this change on<br />

LCOE* appears low. This is because of<br />

the devaluation of money, the impact<br />

of the last 20 years on the LCOE* in<br />

relation to the full lifetime is not that<br />

significant (due to the constant value<br />

calculation).<br />

The LCOE* of all electricity generation<br />

sources is driven by capital costs.<br />

All sources have roughly the same<br />

dependence on the utilisation, as all<br />

need to operate to generate income.<br />

The impact from 100 % to 60 % is<br />

moderate. Below 60 %, the LCOE*<br />

increases fast.<br />

The LCOE* of Hydrogen Round<br />

trip units is extremely high, especially<br />

affected by lower utilisation factor of<br />

electrolysers. At the UF of 20 %, a<br />

typical utilisation factor of a “Peaker”<br />

unit, the LCOE* will increase to above<br />

700 €/MWh.<br />

<strong>Nuclear</strong> power emits no greenhouse<br />

gases. The complete nuclear<br />

power supply chain, from uranium<br />

mining to waste disposal, including<br />

the construction and operation, is<br />

estimated to emit only 2–6 grams of<br />

CO 2 per kilowatt-hour generated. This<br />

is less than even wind and solar, and<br />

up to two orders of magnitude fossil<br />

fuels. <strong>Nuclear</strong> should not be viewed as<br />

being in competition with “renewable”<br />

sources of energy, such as wind or<br />

solar. As the reduction of carbon emissions<br />

becoming a top priority, both<br />

nuclear and renewable sources have<br />

both roles to play.<br />

Possibly the most relevant finding<br />

from the Study is that with the<br />

level playing field <strong>for</strong> all non-carbon<br />

emitting sources <strong>for</strong> electricity,<br />

nuclear is fully competitive and even<br />

dominates other sources in several<br />

areas. The current situation where<br />

VREs are effectively subsidized by<br />

having guaranteed income (i.e. all<br />

VRE generation is taken by the grid<br />

and paid <strong>for</strong> at a predetermined price,<br />

regardless of the need <strong>for</strong> such<br />

electricity) will became impossible<br />

with higher penetration of VREs, as<br />

some will have to periodically shut<br />

down. This, together with system<br />

costs, further undermines the competitiveness<br />

of VREs. On the contrary,<br />

nuclear with its guaranteed dispatchability<br />

and reliability of supply, when<br />

financed with capital costs that are<br />

prevailing in the markets today,<br />

becomes the most af<strong>for</strong>dable non<br />

carbon emitting source of electricity.<br />

Authors<br />

Bojan Tomic<br />

Principal Consultant<br />

ENCO, Vienna, Austria<br />

b.tomic@enco.eu<br />

Bojan Tomic has more than 35 years experience in the<br />

nuclear sector internationally. He started his career as<br />

the designer of nuclear plant safety systems at<br />

Combustion engineering in USA. He was a First officer<br />

at the IAEA’s <strong>Nuclear</strong> safety division, with responsibilities<br />

<strong>for</strong> probabilistic safety assessments and operational<br />

safety. He continued his career as a consultant<br />

with ENCO, advising clients on various aspects of<br />

utilisation of nuclear and radiological technologies<br />

worldwide. He was engaged in numerous modelling<br />

and analytical studies, including due diligence<br />

assessment <strong>for</strong> new nuclear units. Bojan has been<br />

involved with many nuclear safety initiatives at the EU<br />

level, most notably in the EU Post Fukushima Stress<br />

test activities, where he led the peer review team<br />

assessing national stress tests in several countries<br />

including Germany. More recently he was on the<br />

Board of ENSREG’s Topical peer review on Ageing<br />

management of NPPs. Mr Tomic is a member of the<br />

Borssele Benchmark committee.<br />

Mario van der Borst<br />

Principal Consultant<br />

2mario@zeelandnet.nl<br />

Mario van der Borst started his career in R&D at TNO<br />

in the Netherlands. In 1984 he entered the <strong>Nuclear</strong><br />

Industry. He specialized in Thermo-Hydraulics and<br />

Probabilistic Safety Assessments. He was responsible<br />

<strong>for</strong> major back-fitting and O&M projects at the NPP<br />

Borssele. From 2003 till 2010 he was the Technical<br />

Director of this plant. In 2010 he entered the RWE<br />

New Build Team to be responsible <strong>for</strong> Technology,<br />

Authorization and Regulation. At that time RWE was<br />

involved in NNB projects in the UK, Netherlands,<br />

Romania and Bulgaria. He is president of the Dutch<br />

<strong>Nuclear</strong> society. At the moment he is principal<br />

consultant.<br />

Energy Policy, Economy and Law<br />

A Role <strong>for</strong> <strong>Nuclear</strong> in the Future Dutch Energy Mix ı Bojan Tomic and Mario van der Borst

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

BREST-OD-300 – Demonstration<br />

of Natural Safety Technologies<br />

Vadim Lemehov and Valeriy Rachkov<br />

Introduction The article discusses the need to update the strategy <strong>for</strong> the development of nuclear power, various<br />

approaches to the development of large-scale nuclear power. The current state of fast reactor technologies development<br />

is examined through the example of the BREST-OD-300 reactor plant and the closed nuclear fuel cycle (CNFC) in Russia<br />

with highlighting the main problems. The problems of choosing solutions <strong>for</strong> fast reactors and organization of the<br />

nuclear fuel cycle are discussed within the article as well.<br />

Evaluation of prospects <strong>for</strong> the<br />

development of the nuclear power<br />

industry in Russia and other countries<br />

shows the presence of two trends [1]:<br />

1. Focusing on the development of<br />

the nuclear power industry on the<br />

basis of the existing and improved<br />

types of thermal reactors with an<br />

open nuclear fuel cycle that use<br />

mainly U-235. This also includes<br />

possibilities of using a limited additional<br />

fuel resource in the <strong>for</strong>m of<br />

mixed oxide uranium-plutonium<br />

fuel (MOX-fuel). It is obtained by<br />

single recycling of spent nuclear<br />

fuel (SNF) from these reactors,<br />

separation of accumu lated plutonium,<br />

and mixing it with depleted<br />

uranium. Despite a long history,<br />

the share of MOX fuel in the world’s<br />

nuclear fuel pro duction <strong>for</strong> thermal<br />

reactors has never exceeded<br />

5 %, and its production at some<br />

plants ( Belgium, UK) is ceasing.<br />

2. Focusing on the development of the<br />

closed nuclear fuel cycle (NFC)<br />

with the introduction of reactors<br />

ensuring simple nuclear fuel conversion<br />

or nuclear fuel breeding<br />

(BR ≥ 1). These could be conventional<br />

fast neutron reactors (FNRs)<br />

or the light water hard spectrum<br />

reactors (LWRs) previously discussed<br />

in the 1970s and newly<br />

proposed in the United States and<br />

Russia. <strong>Nuclear</strong> fuel breeding<br />

provides full-scale involvement of<br />

natural uranium (with 99.3 %<br />

U-238) in the plutonium- uranium<br />

breeder producing fissionable<br />

plutonium from U-238 and fissionable<br />

U-233 from natural Th-232 in<br />

the breeder reactor.<br />

The first approach involves evergrowing<br />

quantities of natural uranium<br />

that is used less than 1 % energy-wise,<br />

and the amount of accumulated SNF<br />

constantly in creases. In the conditions<br />

of modern energy markets, this<br />

approach is recognized as economically<br />

justified. A concept of<br />

further development of this approach<br />

has spread in the Unites States, which<br />

has the largest nuclear power industry<br />

in the world, and has been promoted<br />

by leading nuclear power plant (NPP)<br />

designers in emerging countries,<br />

where nuclear power engineering is in<br />

progress. According to American<br />

experts, the world‘s known uranium<br />

resources make it possible to stay on<br />

this track <strong>for</strong> a long time.<br />

It is obvious that large-scale nuclear<br />

power engineering can be implemented<br />

only under the second<br />

approach. But development strategies<br />

under this approach are conceptually<br />

different in different countries,<br />

depending on the expected role of<br />

fast-neutron reactor (FNR) in the<br />

structure of the nuclear power industry.<br />

There are three strategies <strong>for</strong> the<br />

<strong>for</strong>mation of large-scale nuclear power<br />

engineering, which can be conditionally<br />

distinguished: [1].<br />

“AS USUAL” Strategy. The United<br />

States in the <strong>for</strong>eseeable future will<br />

rely on thermal light water reactors<br />

(LWRs) with the open NFC, and<br />

provision is made <strong>for</strong> the transition to<br />

SNF reprocessing from LWR (being<br />

accumulated in a tem porary storage<br />

facility <strong>for</strong> 100 years) in order to<br />

reduce the amount of high level waste<br />

(HLW) subject to final disposal by<br />

means of burning of minor actinides<br />

(MA) from HLW in an FNR. At the<br />

same time, FNRs themselves are<br />

considered as noncompetitive energy<br />

generators and possible “cleaners” <strong>for</strong><br />

the dominant LWRs. For such FNRs, a<br />

breeding ratio (BR < 1) is adopted,<br />

and their NFCs remain open, since it<br />

requires a constant external (not from<br />

the NFC) makeup by fissile nuclides. A<br />

possibility of using FNRs with BR ~ 1<br />

and BR > 1 is under consideration,<br />

but their mission remains fundamentally<br />

the same.<br />

Closed NFC with thermal reactors<br />

(TRs). France and Japan, which<br />

do not have their own uranium deposits,<br />

have traditionally built their development<br />

strategies providing <strong>for</strong> the<br />

transition from LWRs with the open<br />

NFC to sodium-cooled FNRs with the<br />

closed NFC and a BR much larger<br />

than 1, ensuring LWR makeup fuel<br />

supply. A similar strategy was considered<br />

and has still been proposed bv a<br />

team of specialists in Russia.<br />

Closed NFC with FNR. The<br />

Russian Strategy Guidelines <strong>for</strong>mulated<br />

in the “Strategy <strong>for</strong> the Development<br />

of Russia’s <strong>Nuclear</strong> <strong>Power</strong> Industry<br />

in the First Half of the 21 st Century”<br />

[2] and worked out in detail in [3] is<br />

based on the concept of large-scale<br />

nuclear power engineering, which can<br />

be used to solve its main tasks by<br />

means of FNRs of moderate power<br />

rate without surplus plutonium produc<br />

tion remaining in the structure of<br />

previously built NPPs with thermal<br />

reactors. In this case, the complete<br />

inner plutonium breeding (IBR » 1)<br />

with dense nitride fuel of equilibrium<br />

composition is important.<br />

Scenarios <strong>for</strong> the <strong>for</strong>mation of<br />

FNRs with the closed NFC should be<br />

based on the actually established<br />

structure of the nuclear power industry.<br />

In this regard, it is important to<br />

understand the difference between<br />

temporary two-component nuclear<br />

power engineering ensuring a gradual<br />

transition from thermal reactors to<br />

FNRs, and basic two-component<br />

nuclear power engineering, where<br />

thermal reactors play a key role and<br />

fast breeder reactors only feed them<br />

with fuel and burn HLW.<br />

The idea of the basic twocomponent<br />

nuclear energetics was<br />

developed in the second half of the<br />

last century under the influence of the<br />

following factors:<br />

p Development of uranium enriched<br />

thermal reactors <strong>for</strong> military<br />

purposes and their further modernization<br />

<strong>for</strong> the civilian power<br />

engineering;<br />

p Understanding of the necessity of<br />

FNRs <strong>for</strong> the development of<br />

nuclear power industry;<br />

p Economic uncompetitiveness of<br />

fast reactors reactors built in<br />

dif ferent countries with their<br />

specific features determined by the<br />

41<br />


Operation and New Build<br />

BREST-OD-300 – Demonstration of Natural Safety Technologies ı Vadim Lemehov and Valeriy Rachkov

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


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ISSN 1431-5254<br />

require ments of a large BR: high power density, use of a<br />

sodium coolant, pro duction of weapon-grade plutonium<br />

in the blanket.<br />

With the development of the uranium enrichment technology,<br />

thermal reactors became the basis of modern<br />

nuclear power engineering, and, <strong>for</strong> more expensive FNRs<br />

with a large BR, they could be used <strong>for</strong> thermal reactors’<br />

makeup fuel supply (with plutonium produced by FNRs)<br />

in case of cheap natural uranium depletion. In such a<br />

two-component nuclear power industry, a large-scale SNF<br />

and MOX fuel circulation is required between fast and<br />

thermal reactors and centralized nuclear fuel recycling<br />

plants.<br />

The “Strategy <strong>for</strong> the Development of Russia’s <strong>Nuclear</strong><br />

<strong>Power</strong> Industry in the First Half of the 21 st Century” [1]<br />

considers two-component nuclear power as a Stage of a<br />

gradual tran sition from thermal to fast neutron reactors,<br />

which <strong>for</strong>ms the basis of the future large-scale power<br />

industry.<br />

The main large-scale development factors of the nuclear<br />

power industry in Russia and the world remain safety and<br />

economic competitiveness with other types of energy<br />

generation. Russia’s nuclear power processing datum<br />

surface on the basis water-water energetic reactors (VVER)<br />

reactors is sufficient <strong>for</strong> the scale of NPP construction and<br />

volume of exports <strong>for</strong>ecasted by the ES-2030. [4] However,<br />

its long- term strategic potential is limited by the inconsistency<br />

of a safety level with requirements <strong>for</strong> large-scale<br />

nuclear power engineering, limited natural uranium<br />

resources, SNF accumulation, and falling competitiveness<br />

due to increased safety measures.<br />

The “Strategy <strong>for</strong> the Development of Russia’s <strong>Nuclear</strong><br />

<strong>Power</strong> Industry in the First Half of the 21 st Century” [2]<br />

defined main conditions <strong>for</strong> natural safety of a large-scale<br />

nuclear power industry:<br />

p Elimination of accidents requiring evacuation, and<br />

especially resettlement of the population and withdrawal<br />

of significant areas from economic use;<br />

p Effective use of energy potential of the extracted fuel<br />

raw materials;<br />

p Circulation of nuclear materials in the fuel cycle<br />

without significant violation of the natural radiation<br />

balance 1 ;<br />

p Technological support of the nonproliferation of<br />

nuclear weapons;<br />

p Ensuring the competitiveness of nuclear power<br />

engineering in comparison with other types of energy<br />

generation.<br />

The abandonment of the thermal reactor plutonium<br />

makeup from the SNF solves the problem of choosing<br />

between a large or small FNR BR in favor of the inner BR<br />

(IBR) close to l. It should be noted again that the smallscale<br />

nuclear energy system (NES) component is an<br />

imperative associated with acceptable safety of the largescale<br />

nuclear power engineer ing, while the choice between<br />

the hybrid NFC (with the enriched uranium makeup) and<br />

a closed NFC (with the plutonium makeup from the FNR<br />

SNF) is a matter of economic feasibility.<br />

Sometimes fears are expressed that in the case of a FNR<br />

BR close to one, it is impossible to increase the power of the<br />

nuclear power plant in a short time (if necessary). But,<br />

firstly, today even the most optimistic <strong>for</strong>ecasts do not<br />

1 Preservation of the natural radiation balance assumes that, after a certain<br />

historically short period of time, the total radioactivity and radiotoxicity of the<br />

waste generated as a result of the NPP operation, reprocessing of irradiated fuel<br />

and land-buried waste will not exceed the total radioactivity and radiotoxicity of<br />

the uranium isotopes extracted from the earth’s crust to supply NPPs with fuel.<br />

Operation and New Build<br />

BREST-OD-300 – Demonstration of Natural Safety Technologies ı Vadim Lemehov and Valeriy Rachkov

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

discern such a scenario <strong>for</strong><br />

the development of nuclear power.<br />

Secondly, if such a scenario turns out<br />

to be in demand, then, without going<br />

beyond the natural safety, it can be<br />

implemented by quickly putting in any<br />

rationally required amount of FNR<br />

capacity with fuel from enriched<br />

uranium or using a blanket, the<br />

presence of which in the countries<br />

of the “nuclear club” meets nonproliferation<br />

requirements.<br />

At present, it can be considered<br />

theoretically proven and computationally<br />

experimentally substantiated<br />

that such three additional<br />

requirements <strong>for</strong> FNR, as IBR close<br />

to 1 [5], lead coolant [6] and dense<br />

nitride uranium-plutonium fuel<br />

(MNIT-fuel) [7], make it possible to<br />

significantly increase the safety<br />

level of FNR that meet these requirements,<br />

in com parison with FNR<br />

with IBR, significantly less than<br />

one (larger only when using a<br />

blanket), with sodium coolant and<br />

MOX fuel mastered in Russia. Thus,<br />

<strong>for</strong> a large-scale component of<br />

nuclear power, an FNR with a IBR<br />

close to unity, with lead coolant<br />

and dense uranium- plutonium fuel<br />

is required.<br />

1. In connection...<br />

with the requirement to increase the<br />

level of safety, in relation to the reactor<br />

installations of NPPs, six main<br />

technical solutions can be distinguished<br />

that ensure the satisfaction<br />

of the natural safety requirements of<br />

large-scale nuclear power, which are<br />

demonstrated in the BREST-OD-300<br />

reactor plant: The equilibrium active<br />

zone of FNR<br />

The equilibrium FNR core allows<br />

minimizing the reactivity margin <strong>for</strong><br />

nuclear fuel burnout and virtually<br />

eliminating instantaneous neutron<br />

acceleration (Figure 1).<br />

2. Dense fuel<br />

Among the fundamental properties<br />

of dense fuel, three play a significant<br />

role in terms of influencing the basic<br />

characteristics of the active zones and<br />

safety: density, thermal conductivity,<br />

and the specific amount of scattering<br />

light elements (oxygen, carbon, and<br />

nitrogen).<br />

A higher fuel density and a smaller<br />

number of light elements contributes<br />

to an increase in the reproduction<br />

coefficient in the reactor core (IBR)<br />

and the integral BR <strong>for</strong> the reactor<br />

plant (RP). Special unique properties<br />

are acquired by active zones with the<br />

so-called “equilibrium” fuel, in which<br />

| Figure 1<br />

Reactivity reserve <strong>for</strong> the campaign of the BREST-OD-300.<br />

the burning of the fissile material is<br />

completely compensated by its reproduction.<br />

Dense fuel allows realizing an<br />

equilibrium core (Figure 2) with a IBR<br />

of about one (Table 1), that provide:<br />

p complete reproduction of fissile<br />

nuclides, which is a sufficient<br />

con dition <strong>for</strong> the practical use of<br />

the energy resource U-238;<br />

p work without a uranium blanket,<br />

which eliminates the production of<br />

low-background radiation with a<br />

quality close to weapons-grade;<br />

p the absence of the need to separate<br />

plutonium from SNF and the<br />

possibility of using technologies<br />

without separating uranium and<br />

plutonium, which together with<br />

the previous advantage provide<br />

technological support <strong>for</strong> the nonproliferation<br />

regime;<br />

p minimization of the burnout<br />

reactivity margin, which reduces<br />

the maximum reactivity margin of<br />

the reactor vessel and increases the<br />

nuclear safety of the reactor vessel;<br />

p unique stability of fuel rods and<br />

fuel assemblies heat release during<br />

their operation.<br />

Currently, more than 1,500 fuel rods<br />

have been tested in the BOR-60 and<br />

BN-600 rector plants, including up to<br />

a burn-up depth of 9.3 % t. a.<br />

3. Wide core grid<br />

The wide grid of the core allows<br />

having a level of natural circulation<br />

sufficient to remove the residual heat<br />

and reduce the power consumption<br />

<strong>for</strong> pumping the coolant.<br />

4. Integrated layout of the<br />

reactor plant<br />

The integrated layout of the reactor<br />

plant (Figure 3) allows excluding the<br />

loss of core cooling.<br />

All primary circuit equipment<br />

required <strong>for</strong> organizing the circulation<br />

circuit and transferring energy to the<br />

heat conversion circuit is located in a<br />

single reactor block.<br />

5. Heavy liquid metal coolant<br />

The choice of lead as a coolant <strong>for</strong> the<br />

BREST-OD-300 reactor plant stems<br />

from:<br />

p the presence of a well-founded<br />

lead coolant technology, i.e. a set<br />

of measures and means to ensure<br />

the required quality of the coolant<br />

and the cleanliness of the primary<br />

circuit during operation;<br />

p low potential energy associated<br />

with possible chemical reactions<br />

involving lead;<br />

p negligible moderating ability of<br />

lead nuclei, which, on the one<br />

hand, eliminates the problem of<br />

the positive void effect of coolant<br />

reactivity, and on the other hand,<br />

| Figure 2<br />

Cartogram a.z. reactor plant BREST-OD-300.<br />

Number of fuel assemblies in the core 169<br />

Core height, mm 1,100<br />

MNIT fuel density, g/cm 3 12.3<br />

Full load of MNIT fuel, t 20.8<br />

Max. burn-up depth in the discharged fuel<br />

(at the initial stage), % t. a.<br />

Average ST temperature at the inlet/outlet<br />

of the core, °C<br />

Average energy intensity of a.z., MWth/m 3 140<br />

Maximum linear power over the core, W/cm 420<br />

| Table 1<br />

Index a.z. reactor plant BREST-OD-300.<br />

9.3 (6.0)<br />

420/535<br />

Reproduction rate (blanket is missing) 1.05<br />


Operation and New Build<br />

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<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


| Figure 3<br />

The view of BREST-OD-300 reactor plant.<br />

allows the use of a wide lattice in<br />

the core, thereby providing an<br />

effective mode of natural circulation<br />

of the coolant in the core with<br />

a simultaneous decrease in coolant<br />

velocity (almost twice as compared<br />

with sodium coolants in a sodiumcooled<br />

fast breeder reactor (BNreactor)<br />

reactor) and hydraulic<br />

resistance of the circulation loop<br />

and, as a consequence, with a reduction<br />

in the power consumption<br />

<strong>for</strong> pumping the coolant;<br />

p low availability of lead nuclei in<br />

the neutron flux, which makes it<br />

possible to switch from a vessel<br />

structure to a pool structure,<br />

charac terized by a high heat capacity,<br />

and place the equipment in a<br />

concrete shaft lined with steel<br />

or cast iron compatible with lead,<br />

with a decrease in the cost of a<br />

reactor installation and an increase<br />

in reactor safety in transient and<br />

emergency processes due to the<br />

thermal inertia of the circuit;<br />

p high boiling point (~ 1745 °C) of<br />

the lead coolant, which excludes<br />

accidents associated with the crisis<br />

of heat exchange (in the reactor,<br />

due to the higher pressure in the<br />

core, the boiling point of lead can<br />

reach 2300 °C).<br />

The above benefits are illustrated in<br />

Figures 4 and 5.<br />

The figures are given <strong>for</strong> the worst<br />

conditions of heat removal from the<br />

reactor core – complete blackout.<br />

There is a shutdown of four reactor<br />

coolant pumps (RCPs) and a cessation<br />

of feed water supply during operation<br />

at the initial nominal power. The<br />

removal of the residual energy release<br />

is carried out by two of the four<br />

emergency core cooling systems<br />

(ECCSs) loops (the failure of the other<br />

two ECCS loops and the failure of the<br />

ECCS is postulated).<br />

Result: <strong>for</strong> all standardized<br />

radionuclides, emissions into the<br />

atmo sphere do not reach the control<br />

level per day.<br />

6. Using ambient air<br />

as an aftercooler<br />

Use of atmospheric air as a final cooler<br />

without intermediate circuits in the<br />

case of natural circulation removal of<br />

residual heat in a high-power reactor<br />

plant (Figure 6).<br />

In addition to the safety requirements<br />

<strong>for</strong> nuclear power plants, there<br />

are a number of requirements <strong>for</strong><br />

closed NFC technologies, which<br />

are implemented at the Industrial<br />

pilot facility with a power complex<br />

with the BREST OD-300 reactor, a<br />

plant <strong>for</strong> the production of nuclear<br />

fuel from the products of reprocessing<br />

of spent nuclear fuel and a<br />

plant <strong>for</strong> repro cessing spent nuclear<br />

fuel:<br />

p low-waste reprocessing spent<br />

nuclear fuel from FNR;<br />

p involvement of SNF reprocessing<br />

products from thermal reactors<br />

into the nuclear reactor fuel cycle;<br />

p reduction of the duration the spent<br />

nuclear fuel spends on the nuclear<br />

reactor be<strong>for</strong>e its reprocessing to<br />

1 – 2 years;<br />

p ensuring the radiation balance<br />

between the extracted fuel raw<br />

materials and the buried radioactive<br />

waste (RW);<br />

p technological support <strong>for</strong> the<br />

nonproliferation regime.<br />

| Figure 4<br />

Change in power (1) and flow through the reactor (2).<br />

| Figure 5<br />

Temperature change of fuel (1) and fuel element cladding (2).<br />

Operation and New Build<br />

BREST-OD-300 – Demonstration of Natural Safety Technologies ı Vadim Lemehov and Valeriy Rachkov

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

| Figure 6<br />

ECCS plan.<br />

In connection with the requirements<br />

<strong>for</strong> the technologies of the closed<br />

NFC, three technical solutions can<br />

be distinguished:<br />

p “dry” reprocessing of spent<br />

nuclear fuel from FNR to reduce<br />

the duration of spent nuclear fuel<br />

holding be<strong>for</strong>e reprocessing and to<br />

exclude the separation of pure<br />

plutonium during reprocessing;<br />

p transmutation of minor actinides<br />

in FNR to ensure a balance<br />

between the extracted fuel raw<br />

material and the disposed radioactive<br />

waste;<br />

p abandonment of the blanket in<br />

FNR to exclude the production of<br />

weapon-grade plutonium (when<br />

exporting technologies).<br />

The question remaining is competitiveness<br />

of NPPs in general and on the<br />

basis of FNR in particular. Obviously,<br />

without norms and standards corresponding<br />

with the new technological<br />

nuclear power plat<strong>for</strong>m the solution<br />

of this question is difficult. The first<br />

approach to the answer about the feasibility<br />

of competitive CNFC power<br />

engineering based on fast neutron reactors<br />

will be given by conceptual projects<br />

of industrial power facilities with<br />

reactor plants BN-1200 and BR-1200.<br />

balance between the extracted fuel<br />

raw material and buried RAW) are<br />

preferable <strong>for</strong> the large-scale<br />

nuclear power engineering in<br />

general.<br />

3. To prove the advantages of reactors<br />

with lead coolant, a pilot demonstration<br />

power complex is being<br />

created at the site of JSC Siberian<br />

Chemical Combine (SKhK).<br />

4. Answers to the questions related to<br />

the industrial production and<br />

application of MNIT fuel <strong>for</strong> the<br />

IPF on the BN-1200 and BR-1200<br />

basis can be given only in case of its<br />

pilot application in the BREST-<br />

OD-300 reactor plant of the industrial<br />

pilot facility.<br />

5. Answers to the questions related to<br />

the industrial reprocessing of<br />

MNIT-SNF <strong>for</strong> the isotope production<br />

facilities (IPF) can be given<br />

only in the operation of the<br />

processing module on the pilot<br />

demonstration facility.<br />

6. Technological support of the nonproliferation<br />

regime in the export<br />

version of natural safety technologies<br />

is not a complete solution to<br />

the nonproliferation problem but<br />

only an important addition to<br />

institutional tools of its solution.<br />

7. For a radical solution to the CO 2<br />

problem, it is possible to develop a<br />

large-scale nuclear power industry<br />

by the end of this century, which<br />

means a gradual transition to FNRs<br />

with closed NFC in the nearest<br />

future.<br />

8. The main requirement <strong>for</strong> the<br />

development of the nuclear power<br />

industry is its competitiveness,<br />

primarily with the generation<br />

based on organic fuels and with<br />

renewable energy sources in terms<br />

of exports. Preliminary calculations<br />

<strong>for</strong> industrial power complexes<br />

with fast reactors operating<br />

in a closed fuel cycle show the<br />

possibility of achieving parity with<br />

other types of generation.<br />

RP<br />

RW<br />

SNF<br />

TR<br />

VVER<br />

Reactor Plant<br />

Radioactive Waste<br />

Spent <strong>Nuclear</strong> Fuel<br />

Thermal Reactor<br />

Water-Water Energetic Reactor<br />

Preferences<br />

[1] New Technological Plat<strong>for</strong>m <strong>for</strong> the National <strong>Nuclear</strong> Energy<br />

Strategy Development / Adamov E.O., Rachkov V.I. // Russian<br />

Academy of Sciences Bulletin.<br />

Energy. – 2017.– No. 2. – P. 3-12.<br />

[2] Development Strategy of the Russian <strong>Nuclear</strong> <strong>Power</strong> Industry<br />

<strong>for</strong> the First Half of the XXI Century. Main Provisions, Minatom<br />

Rossii, Moscow, 2000. – 26 p.<br />

[3] E. O. Adamov, A. V. Dzhalavyan, A. V. Lopatkin,<br />

N. A. Molokanov, E. V. Murav’ev, V. V. Orlov, S. G. Kalyakin,<br />

V. I. Rachkov, V. M. Troyanov, E. N. Avrorin, V. B. Ivanov, and<br />

R. M. Aleksakhin, Conceptual Provisions of the Development<br />

Strategy of the Russian <strong>Nuclear</strong> <strong>Power</strong> Industry in Prospect up<br />

to 2100 - NIKIET, Moscow, 2012. – 61 p.<br />

[4] Energy strategy of Russia <strong>for</strong> the period up to 2030<br />

[approved. by order of the Government of the Russian<br />

Federation of November 13, 2009 No. 1715-r].<br />

[5] E. O. Adamov, et al., White Book of <strong>Nuclear</strong> <strong>Power</strong><br />

Engineering – NIKIET, Moscow, 2001. – 496 p.<br />

[6] E. O. Adamov, V. I. Rachkov, et al., “Choice of coolant <strong>for</strong><br />

nuclear power plant with inherent safety,” Izv. Ross. Akad.<br />

Nauk Energ., No. 6, 3 − 14, 2015<br />

[7] E. O. Adamov, L. M. Zabud’ko, V. I. Matveev, V. I. Rachkov, V.<br />

M. Troyanov, Yu. S. Khomyakov, and V. N. Leonov,<br />

“ Comparative study of advantages and disadvantages of the<br />

use of metal and mixed nitride uranium- plutonium fuel in fast<br />

reactors,” Izv. Ross. Akad. Nauk., Energ., No. 2, 3 − 15, 2015.<br />

Authors<br />

Vadim Lemehov<br />

Chief Designer and<br />

Technical Committee<br />

member of the Proryv<br />

Project*<br />

rvi@proryv2020.ru<br />

Valeriy Rachkov<br />

Research and Development<br />

Chief Scientific<br />

Officer of the Proryv<br />

Project* as well as<br />

Technical Committee<br />

member<br />


Conclusions<br />

1. A large-scale element of twocomponent<br />

nuclear power engineering,<br />

i.e. a closed nuclear fuel<br />

cycle FNR, requires an FNR with<br />

the inner breeding rate close to 1<br />

with a lead coolant and dense<br />

uranium- plutonium fuel to ensure<br />

the necessary safety level.<br />

2. Low-waste “dry” SNF reprocessing<br />

(mainly to reduce a duration of the<br />

SNF conditioning be<strong>for</strong>e its reprocessing)<br />

and minor actinide transmutation<br />

(to ensure a radiation<br />

Abbreviations<br />

BN Sodium-Cooled Fast Breeder Reactor<br />

BR Breeding Ratio<br />

CFC Closed fuel cycle<br />

ECCS Emergency Core Cooling Systems<br />

FNR Fast-Neutron Reactor<br />

HLW High Level Waste<br />

IBR Inner Breeding Ratio<br />

IPF Isotope Production Facilities<br />

LWR Light Water Reactor<br />

MA Minor Actinides<br />

MNIT Mixed Uranium-Plutonium Nitride Fuel<br />

NES <strong>Nuclear</strong> energy system<br />

NFC <strong>Nuclear</strong> Fuel Cycle<br />

NPP <strong>Nuclear</strong> <strong>Power</strong> Plant<br />

RCP Reactor Coolant Pump<br />

* Proryv project<br />

is implemented<br />

by Rosatom<br />

Operation and New Build<br />

BREST-OD-300 – Demonstration of Natural Safety Technologies ı Vadim Lemehov and Valeriy Rachkov

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

46<br />


<strong>Nuclear</strong> Innovation Alliance (NIA)<br />

The <strong>Nuclear</strong> Innovation Alliance (NIA) is focused on championing cuttingedge<br />

solutions to the climate challenges of this century. NIA is a non- partisan,<br />

non-profit, “think-and-do” tank working to ensure advanced nuclear energy<br />

can be a part of the climate solution. By engaging with policymakers,<br />

industry, and other stakeholders, NIA works on licensing modernization,<br />

policy development, and industry commercialization to bring economicallycompetitive,<br />

zero-carbon energy to U.S. and global markets. Advanced<br />

nuclear energy technologies face economic, political, and social obstacles<br />

to successful development, demonstration, and commercialization. NIA<br />

believes these obstacles can be overcome by encouraging public and private<br />

investment in advanced nuclear innovation at a scale adequate to drive<br />

meaningful innovation, and by building strong public trust in emerging<br />

technologies through collaboration among industry, government, labor, and<br />

civil society.<br />

NIA approaches its education and engagement ef<strong>for</strong>ts<br />

thoughtfully, by producing technically-in<strong>for</strong>med analysis<br />

and policy recommendations <strong>for</strong> policymakers, investors,<br />

and members of the public. It in<strong>for</strong>ms licensing<br />

moder nization ef<strong>for</strong>ts at the U.S. <strong>Nuclear</strong> Regulatory<br />

Com mission (NRC), educates policymakers in the<br />

legislative and executive branches, and promotes<br />

commercialization through collaboration with industry.<br />

NIA also promotes entrepreneurialism through its annual<br />

<strong>Nuclear</strong> Innovation Bootcamp.<br />

“NIA’s highest objective is to help achieve the conditions<br />

<strong>for</strong> advanced nuclear energy success. We believe<br />

advanced nuclear energy is key to making substantial<br />

and identifiable progress in climate protection. NIA is an<br />

advocacy hub <strong>for</strong> advanced nuclear energy policy in the<br />

United States, and is building a durable and sustainable<br />

organization with an expanding base of support,” says<br />

Judi Greenwald, NIA Executive Director.<br />

Currently, NIA is primarily funded through charitable<br />

grants and philanthropic donations from climateconcerned<br />

individuals and foundations. With its strong<br />

policy research base, NIA regularly works with policymakers<br />

and fellow NGOs, including The Breakthrough<br />

Institute, Clean Air Task Force, ClearPath, Good Energy<br />

Collective, and Third Way. The organization also reaches<br />

out into the broader nuclear energy ecosystem by<br />

actively engaging with advanced nuclear developers<br />

and investors, as well as universities, national laboratories,<br />

and other technical research institutions. More<br />

recently, NIA has also begun to work collaboratively with<br />

stakeholders outside of the nuclear sector, including<br />

environmentalists, other clean energy industries, labor,<br />

and energy consumers.<br />

History<br />

NIA was created in 2015 after the Clean Air Task Force<br />

spun off its advanced nuclear program under Dr. Ashley<br />

Finan into a separate organization. Under Dr. Finan’s<br />

leadership, NIA quickly emerged as a leader in analysis,<br />

stakeholder convening, and advocacy <strong>for</strong> advanced<br />

reactors. Through a mix of coordination, reports, and<br />

Congressional testimony, NIA played a major role in the<br />

development and passage of two major pieces of<br />

legislation:<br />

The <strong>Nuclear</strong> Ecosystem and the NIA’s Role in Innovation<br />

P The <strong>Nuclear</strong> Energy Innovation and Modernization<br />

Act (NEIMA), which required re<strong>for</strong>ms at the NRC to<br />

facilitate the licensing of advanced reactors, including<br />

the development of a risk-in<strong>for</strong>med, per<strong>for</strong>mancebased,<br />

technology-inclusive pathway.<br />

P The <strong>Nuclear</strong> Energy Innovation and Capabilities Act<br />

(NEICA), to support U.S. Department of Energy<br />

research activities and to ensure national research<br />

assets facilitate private innovation.<br />

At a Glance<br />

<strong>Nuclear</strong> Innovation Alliance (NIA)

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Beyond these two major successes, the NIA also worked<br />

on nuclear export control re<strong>for</strong>m, nuclear energy geopolitics,<br />

and other priority areas <strong>for</strong> the industry.<br />

In 2019, Dr. Finan departed NIA to head Idaho National<br />

Laboratory’s newly <strong>for</strong>med <strong>Nuclear</strong> Reactor Innovation<br />

Center, an institution created by NEICA. In 2020, Judi<br />

Greenwald was selected to replace Dr. Finan, bringing an<br />

extensive background in energy and environmental<br />

policy leadership in Washington, DC. Recently, NIA has<br />

grown its staff as the pace of licensing modernization<br />

and commercialization <strong>for</strong> advanced reactors grows.<br />

From one employee at its founding, NIA is set to reach<br />

four employees in summer 2021, supported by fellows<br />

and outside consultants.<br />

Building on its success in helping pass NEIMA, NIA is<br />

pursuing an ambitious research agenda to in<strong>for</strong>m<br />

licensing modernization at the NRC. NIA continues to<br />

monitor and support NRC ef<strong>for</strong>ts to develop Part 53, a<br />

per<strong>for</strong>mance-based licensing pathway <strong>for</strong> advanced<br />

reactors. NIA is also conducting research on potential<br />

NRC fee re<strong>for</strong>ms to reduce barriers to reactor innovation,<br />

identifying ways to shorten the duration of NRC reviews,<br />

and evaluating how to make U.S. licensing compatible<br />

with international approaches.<br />

Beyond its regulatory work, NIA engages extensively<br />

with policymakers as they endeavor to enact and<br />

implement new laws to drive nuclear innovation.<br />

47<br />


Organization<br />

NIA is overseen by its Board of Directors, and consults<br />

with its Industry Innovation Leadership Council and<br />

Advisory Committee, to ensure its approach to achieving<br />

conditions <strong>for</strong> success encompasses a broad range of<br />

interests and perspectives, including investors, government<br />

leadership, and the public.<br />

NIA’s Industry Council is a <strong>for</strong>um <strong>for</strong> advanced reactor<br />

developers to discuss innovation challenges and opportunities.<br />

Re<strong>for</strong>med in early 2021, the Council in<strong>for</strong>ms the<br />

NIA’s strategy and activities but does not set NIA policy.<br />

The current members of the Council include leading<br />

advanced reactor developers in the U.S.:<br />

P BWX Technologies, Inc.<br />

P Framatome,<br />

P GE Hitachi<br />

P General Atomics<br />

P Holtec<br />

P Kairos<br />

P NuScale<br />

P Oklo<br />

P Terrapower<br />

P Terrestrial Energy USA<br />

P Ultra Safe <strong>Nuclear</strong> Corporation<br />

P Westinghouse<br />

P X-Energy<br />

Ongoing Activities<br />

Today, NIA is engaged in many activities to catalyze the<br />

development of advanced nuclear energy. In February,<br />

NIA and the Partnership <strong>for</strong> Global Security released a<br />

joint strategy <strong>for</strong> U.S. leadership on commercialization of<br />

advanced reactors. The report, titled “U.S. Advanced<br />

<strong>Nuclear</strong> Energy Strategy <strong>for</strong> Domestic Prosperity, Climate<br />

Protection, National Security, and Global Leadership,”<br />

details a whole-of-society approach; with collaboration<br />

between government, industry, civil society, and other<br />

nations that can bring advanced reactors to market to<br />

reduce global emissions, provide domestic jobs, and<br />

support national security. The Strategy and other reports<br />

by NIA are available on the NIA website.<br />

<strong>Nuclear</strong> Innovation Bootcamp<br />

NIA is a proud sponsor and organizing partner of the<br />

<strong>Nuclear</strong> Innovation Bootcamp, an annual workshop that<br />

introduces select students and early career professionals<br />

to advanced nuclear energy and the 21st century energy<br />

landscape. Over the span of two weeks, participants<br />

engage in multi-disciplinary classes and workshops<br />

delivered by a broad array of presenters, all while<br />

developing group ventures that are ultimately pitched to<br />

industry leaders. Past Bootcamps have incorporated a<br />

diverse range of topics including technology, marketing,<br />

policy, and public relations. Bootcamp alumni are active<br />

across industry, academia, and the policy space.<br />

In 2016, the first <strong>Nuclear</strong> Innovation Bootcamp was held.<br />

The program convened twenty-five students from<br />

around the world at UC Berkeley, where the students<br />

developed and pitched nuclear start-up concepts to a<br />

panel of judges. Using lessons learned from the inaugural<br />

edition, the program <strong>for</strong>mat was enhanced and<br />

remained at UC Berkeley <strong>for</strong> the following two years. In<br />

2019, the Bootcamp, “Atoms in Action,” was hosted at<br />

the OECD <strong>Nuclear</strong> Energy Agency in Paris, France.<br />

Twenty- seven students and young professionals from<br />

10 countries and 4 continents took part that year, the<br />

Bootcamp’s first edition in Europe. While there, they<br />

drew upon experience from the established French<br />

nuclear industry and learned about exciting developments<br />

taking place in the European advanced nuclear<br />

sphere.<br />

In light of the COVID-19 pandemic, the 2020 Bootcamp’s<br />

programming was abbreviated, moved online, and<br />

opened to past alumni. Due to ongoing public health<br />

concerns and travel restrictions, the NIA and other<br />

cooperating organizations are looking to build on the<br />

success of the 2020 online experience and develop an<br />

equally engaging program <strong>for</strong> 2021.<br />

Contact<br />

www.nuclearinnovationalliance.org<br />

@theNIAorg<br />

At a Glance<br />

<strong>Nuclear</strong> Innovation Alliance (NIA)

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

48<br />


Safety-related Residual Heat Removal<br />

Chains of German Technology Pressure<br />

Water Reactors (Light and Heavy Water)<br />

Franz Stuhlmüller and Rafael Macián-Juan<br />

Introduction The <strong>Nuclear</strong> <strong>Power</strong> Plants (NPPs) with Pressure Water Reactor <strong>for</strong> enriched fuel (PLWR, Pressurized<br />

Light Water Reactor) and <strong>for</strong> natural uranium (PHWR, Pressurized Heavy Water Reactor), developed in Germany, are<br />

largely identical in their basic design. However, there is a striking difference in the scope of the main reactor systems.<br />

While in PLWR these only consist of Reactor and Reactor Coolant System including Pressurizer and Pressurizer Relief<br />

Tank, in PHWR the Moderator System is added. In power operation of a PLWR, the entire thermal reactor power is<br />

transferred to the water/steam cycle via the Steam Generators. In PHWR, on the other hand, part of the power has to be<br />

removed - at a lower temperature level - from the moderator, which is spatially separated from the main reactor coolant<br />

within the Reactor Pressure Vessel, but is kept at the same pressure via function-related compensating openings. This<br />

portion of power is used to preheat the feed water be<strong>for</strong>e it enters the Steam Generators. The Moderator System<br />

installed <strong>for</strong> this purpose can also be used in a second function as the inner link in the Residual Heat Removal Chain<br />

(RHRC) <strong>for</strong> cooling the Reactor after it has been switched off. In PLWR the analog system is operated exclusively <strong>for</strong> the<br />

removal of residual heat from the Reactor and, if necessary, the Fuel Pool. In the following, the development steps of the<br />

RHRC of both NPP lines are shown and the main differences between both NPP-types in this regard are explained by<br />

comparing the most recently erected plants, DWR 1300 MW (KONVOI) and Atucha 2.<br />

*In the case of sump<br />

operation after loss of<br />

coolant, the extraction<br />

does not take place<br />

from the reactor system,<br />

but from the floor<br />

(sump) of the Reactor<br />

Building Interior. With<br />

the PLWR, this is<br />

achieved by switching<br />

to a separate suction<br />

line in the intake to the<br />

Residual Heat Removal<br />

Pump. The PHWR uses<br />

the Safety Injection<br />

Pump <strong>for</strong> this – possibly<br />

in parallel operation<br />

with the Moderator<br />

Pump – which thus<br />

becomes part of the<br />

RHRC. In the further<br />

explanations and<br />

figures these RHRC<br />

special variants are not<br />

considered.<br />

Residual Heat Removal Chain,<br />

Structure and Terms<br />

Figure 1 shows the basic structure of<br />

the RHRC using the example of a plant<br />

with four cooling lines, as is the case<br />

with DWR 1300 MW and Atucha 2<br />

(CNA 2). The figure also illustrates the<br />

terms “system” (or “RHR link”), “subsystem”,<br />

“RHR line” (resp. “redundancy”)<br />

and “RHR Chain”. While a<br />

“system” contains the entirety of all<br />

“subsystems” of an RHR link (horizontal<br />

unit), each “RHR line” is made up<br />

of three contiguous subsystems, from<br />

heat source to heat sink (vertical unit).<br />

All RHR lines together <strong>for</strong>m the “RHR<br />

Chain” (although in normal usage a<br />

chain is understood to mean what is<br />

referred to here as a line).<br />

(Redundancy)<br />

Line<br />

Removal<br />

Heat<br />

Residual<br />

Residual Heat<br />

Removal<br />

System/<br />

Moderator-<br />

System<br />

Safety Component<br />

Cooling System/<br />

RHR Intermediate<br />

Cooling System<br />

Secured Service<br />

Cooling Water<br />

System<br />

1<br />

2<br />

3 4<br />

5<br />

Subsystem<br />

1<br />

2<br />

3 4<br />

5<br />

Reactor<br />

Heat Sink<br />

1<br />

2<br />

3 4<br />

5<br />

The RHRC thus consists of three<br />

procedural systems, namely<br />

p a circulation system <strong>for</strong> reactor<br />

coolant or moderator, connected<br />

to the reactor cooling loops or<br />

directly to the Reactor Pressure<br />

Vessel*,<br />

p an intermediate cooling system,<br />

which takes heat from it in heat<br />

exchangers, and<br />

p transfers it in other heat exchangers<br />

via the Secured Service<br />

Cooling Water System to the external<br />

heat sink. “Secured” expresses<br />

that the system – like the entire<br />

RHRC – has a fail-safe design and<br />

that its electrical units can be<br />

operated via the NPPs Emergency<br />

<strong>Power</strong> Supply, if necessary.<br />

1<br />

2<br />

3 4<br />

5<br />

Residual Heat Removal Chain<br />

1<br />

2<br />

3<br />

4<br />

5<br />

Residual Heat Removal Pump/<br />

Moderator Pump<br />

Residual Heat Exchanger/<br />

Moderator Cooler<br />

Component Cooling Pump/<br />

RHR Intermediate Cooling Pump<br />

Component Cooling<br />

Heat Exchanger/<br />

RHR Intermediate Cooling<br />

Heat Exchanger<br />

Secured Service Cooling<br />

Water Pump<br />

| Figure 1<br />

Residual Heat Removal from the Reactor; Definition of “System” (or “RHR link”), “Sub-System”,<br />

“RHR Line” and “RHR Chain”.<br />

Temporal Development<br />

of the RHRC<br />

The development steps up to the latest<br />

versions of the RHRC <strong>for</strong> PLWR and<br />

PHWR go hand in hand with the<br />

chronological growth of the unit sizes<br />

of both NPP variants from the second<br />

half of the 1960s to the end of the<br />

1980s (Figure 2).<br />

Starting with MZFR (multi- purpose<br />

research reactor Karlsruhe) as a prototype<br />

NPP of a PHWR and KWO<br />

(Obrigheim nuclear power plant) as a<br />

PLWR demonstration plant, the unit<br />

power outputs increased with almost<br />

constant gradients,<br />

p at the PLWR version via KKS ( Stade<br />

nuclear power plant) to the KWB-A<br />

plant (Biblis nuclear power plant,<br />

Unit A). This was followed by a<br />

consolidation phase with the<br />

construction of several (1200 to)<br />

1300 MWel class NPPs (be<strong>for</strong>e<br />

the step towards an EPR size of<br />

≥ 1600 MWel was taken),<br />

p at the PHWR with a significantly<br />

flatter course via Atucha 1 (CNA 1)<br />

to CNA 2 plant as the last NPP of<br />

this type to date.<br />

Hereinafter, the RHRC concepts of all<br />

of the above power plants (without<br />

EPR) are shown in their original<br />

version. Later retrofittings, e.g. as<br />

adaptation measures to tightened<br />

safety regulations are not considered.<br />

In the first plants – both PLWR and<br />

PHWR – the single-line concept or<br />

multi-line in meshed construction was<br />

common <strong>for</strong> the systems of the RHRC.<br />

Here e. g. cross-connections between<br />

individual subsystems of an RHR link<br />

Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

| Figure 2<br />

Temporal Development of unit net power of german-type PLWR and PHWR plants.<br />

are established, via which, if necessary,<br />

a standby pump can optionally be<br />

connected to several circuits. However,<br />

this design pre supposes that failure of<br />

passive system parts, such as piping,<br />

does not have to be assumed. The<br />

extension of scenarios to be controlled,<br />

in particular the postulate that in the<br />

event of an accident, in addition to<br />

the maintenance or repair of a component,<br />

a single failure also occurs on<br />

any system part, led to transition to<br />

the completely line-separated concept<br />

with three or four RHR-lines <strong>for</strong> the<br />

RHRC, depending on the unit size. This<br />

change took place step by step <strong>for</strong> both<br />

types of NPP, with the line separation<br />

developing from the inner to the outer<br />

link of the cooling chain, i.e. starting<br />

with the Moderator System (PHWR)<br />

resp. the Residual Heat Removal<br />

System (PLWR) up to the Secured<br />

Service Cooling Water System.<br />

The following descriptions are<br />

exclusively in the present <strong>for</strong>m, also<br />

<strong>for</strong> the plants that have already been<br />

decommissioned.<br />

NPPs with Pressurized Light<br />

Water Reactor<br />

Immediately after switching off a<br />

PLWR power plant, cooling of the<br />

reactor system basically takes place<br />

via the Steam Generators (exception:<br />

loss of coolant accidents above certain<br />

leak sizes). At the time, when cooling<br />

is taken over by the RHRC, pressure<br />

and temperature of the reactor cooling<br />

circuit have already been reduced to<br />

such an extent, that the design values<br />

<strong>for</strong> the Residual Heat Removal System<br />

can be kept significantly lower than<br />

those of the reactor system. The heat<br />

to be removed has sunk so far, that an<br />

intermediate cooling system, designed<br />

<strong>for</strong> low temperature and low pressure,<br />

can be used on the secondary side of<br />

the Residual Heat Exchanger. This<br />

intermediate cooling system (called<br />

“Component Cooling System”) supplies<br />

further safety- related and operational<br />

cooling points in parallel to the<br />

Residual Heat Exchanger. If the RHRC<br />

has a multi-line structure at least up to<br />

and including the Component Cooling<br />

System, then two component cooling<br />

subsystems are designed so that –<br />

alternating – they can supply cooling<br />

water to all of the operational cooling<br />

consumers (e.g. of Reactor Coolant<br />

Pumps and nuclear auxiliary systems)<br />

in addition to their line- associated<br />

safety-related cooling points.<br />

NPP Obrigheim (KWO),<br />

283 MWel<br />

The RHRC is <strong>for</strong>med from one line,<br />

i. e. each RHR link from one circuit.<br />

The Residual Heat Removal System<br />

here includes two Residual Heat<br />

SG<br />

RCP<br />

3<br />

5<br />

Reactor<br />

4 7<br />

6<br />

1<br />

2<br />

8<br />

SG<br />

RCP<br />

| Figure 3<br />

KWO, Reactor Coolant System and RHR Chain.<br />

Removal Pumps connected in parallel<br />

and two Residual Heat Exchangers,<br />

both of which are integrated on their<br />

secondary side in the single component<br />

cooling circuit [1].<br />

Special features of KWO are:<br />

p The additional use of the Residual<br />

Heat Exchangers as low-pressure<br />

coolers within the Volume Control<br />

System (not shown in Figure 3),<br />

p Two Emergency Secured Service<br />

Cooling Water Pumps (in addition<br />

to the regular two Secured Service<br />

Cooling Water Pumps).<br />

NPP Stade (KKS), 630 MWel<br />

The Residual Heat Removal System as<br />

the inner link of the RHRC is carried<br />

out in two subsystems, but is still<br />

mesh-designed with one Residual<br />

Heat Exchanger und two Residual<br />

Heat Removal Pumps each [2], [3],<br />

[4]. The other two RHR links consist –<br />

like at KWO – of only one circulation<br />

system each, but with special features.<br />

These are:<br />

p Three Component Cooling Pumps,<br />

p Three Component Cooling Heat<br />

Exchangers connected in parallel<br />

(which were probably activated as<br />

required),<br />

p Two additional Emergency Component<br />

Cooling Pumps (not shown<br />

in Figure 4),<br />

p Three Service Cooling Water<br />

Pumps.<br />

NPP Biblis Unit A (KWB-A),<br />

1150 MWel<br />

With KWB-A, already in 1975 the<br />

RHRC took the shape, which subsequently<br />

– with a few safety-relevant<br />

additions – became the standard and<br />

Main Steam System<br />

Reactor Coolant System<br />

Residual Heat<br />

Removal System<br />

Component Cooling<br />

System<br />

Secured Service<br />

Cooling Water System<br />

SG Steam Generator<br />

RCP Reactor Coolant Pump<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

7<br />

8<br />

Residual Heat Removal Pumps<br />

Residual Heat Exchangers<br />

Component Cooling Pump(s)<br />

Component Cooling<br />

Heat Exchanger<br />

Secured Service<br />

Cooling Water Pumps<br />

Emergency Secured<br />

Service Cooling Water Pumps<br />

Further Component Cooling<br />

Water Consumers<br />

Further Secured Service<br />

Cooling Water Consumers<br />


Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


SG<br />

RCP<br />

3<br />

5<br />

4<br />

SG<br />

2<br />

4<br />

Reactor<br />

RCP<br />

RCP<br />

has since been used <strong>for</strong> all following<br />

PLWR plants [5], [6]. The number of<br />

RHR lines usually, but not necessarily,<br />

corresponds to the number of reactor<br />

cooling loops. For this size of units<br />

(and also <strong>for</strong> the EPR concept<br />

(≥ 1600 MWel) four Steam Generators<br />

and thus four reactor cooling<br />

loops are required <strong>for</strong> heat transfer to<br />

the water/steam cycle in power operation.<br />

Accordingly, the RHRC also<br />

consists of four independent RHR<br />

lines with a heat transfer capacity of<br />

50 % each, based on the design case.<br />

1<br />

6<br />

4<br />

RCP<br />

2<br />

SG<br />

| Figure 4<br />

KKS, Reactor Coolant System and RHR Chain.<br />

SG<br />

Main Steam System<br />

Reactor Coolant System<br />

Residual Heat<br />

Removal System<br />

Component Cooling<br />

System<br />

Secured Service<br />

Cooling Water System<br />

SG Steam Generator<br />

RCP Reactor Coolant Pump<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

Residual Heat Removal Pumps<br />

Residual Heat Exchangers<br />

Component Cooling Pumps<br />

Component Cooling<br />

Heat Exchangers<br />

Secured Service<br />

Cooling Water Pumps<br />

Further Component Cooling<br />

Water Consumers<br />

(Note: Even <strong>for</strong> plants with only three<br />

reactor cooling loops, this “one to<br />

one” assignment of loop and line<br />

number can be obtained without<br />

violating the safety philo sophy (repair<br />

and simultaneously single-failure)<br />

when the heat transfer capacity of<br />

each line is increased to 100 %.) In<br />

Figure 5, the two inner component<br />

cooling circuits are designed <strong>for</strong> the<br />

alternating supply of operational<br />

component points. For this purpose,<br />

in addition to the regular Component<br />

Cooling Pump, a second pump is<br />

connected in parallel, operated in case<br />

of a very high cooling water demand.<br />

NPPs of DWR 1300 MW class<br />

The increasing safety-related requirements,<br />

set down e. g. in the “RSK<br />

Guidelines <strong>for</strong> Pressurized Water<br />

Reactors” [7] and in “Safety Regulations<br />

of the KTA” [8], [9], in<br />

particular<br />

p elevated awareness of the fuel pool<br />

inventory as a source of activity,<br />

and<br />

p the inclusion of “civilizationrelated<br />

external impacts” (aircraft<br />

crash, explosion pressure waves,<br />

third part influences) as cases to be<br />

managed,<br />

led to important extensions <strong>for</strong> the<br />

system technology of the steam<br />

generator feed as well as <strong>for</strong> the RHRC<br />

[10].<br />

With the Emergency Feed Water<br />

System, a possibility of short- and<br />

medium-term heat removal from the<br />

Reactor Coolant System via the Steam<br />

Generators was created, independent<br />

of the Feed Water Tank and the regular<br />

Emergency <strong>Power</strong> Supply. For the<br />

subsequent long-term cooling via the<br />

so-called Emergency Cooling Chain<br />

(ECC) in this two of the four RHR<br />

lines, whose residual heat removal<br />

circuits contain a Fuel Pool Cooling<br />

Pump,<br />

p an Emergency Component Cooling<br />

Pump within the Safety Component<br />

Cooling System*, and<br />

p an Emergency Secured Service<br />

Cooling Water Pump in the Secured<br />

Service Cooling Water System.<br />

Operational<br />

Cooling points<br />

Reactor Reactor<br />

Building Building<br />

Interior Annulus<br />

Reactor<br />

Auxiliary<br />

Building<br />

SG<br />

Main Steam System<br />

Reactor Coolant System<br />

Residual Heat<br />

Removal System<br />

Component Cooling<br />

System (safety-related part)<br />

Component Cooling<br />

System (operational part)<br />

Secured Service<br />

Cooling Water System<br />

Steam Generator<br />

RCP Reactor Coolant Pump<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

Residual Heat Removal Pumps<br />

Residual Heat Exchangers<br />

Component Cooling Pumps<br />

Component Cooling<br />

Heat Exchangers<br />

Secured Service<br />

Cooling Water Pumps<br />

Further Component Cooling<br />

Water Consumers<br />

7 Further Secured Service<br />

Cooling Water Consumers<br />

| Figure 5<br />

KWB-A, Reactor Coolant System and RHR Chain.<br />

Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

Emergency Feed<br />

Water System<br />

1<br />

8 9 10<br />

G<br />

11<br />

SG<br />

4<br />

1a<br />

2<br />

RCP<br />

5<br />

SG<br />

are installed in parallel to the existing<br />

pumps.<br />

The Fuel Pool Cooling Pumps<br />

themselves act as “Emergency Residual<br />

Heat Removal Pumps” as part of<br />

the Residual Heat Removal System in<br />

this case. If required, all this pumps<br />

are supplied with power via the<br />

Emergency Generators, which – after<br />

the Emergency Feed Water Pumps<br />

have been disconnected – are driven<br />

by the Emergency Diesel Engines.<br />

For the fuel pool cooling, in<br />

addition to the two RHR lines that<br />

include the Fuel Pool Cooling Pumps,<br />

there is also another fuel pool cooling<br />

circuit whose single cooler is supplied<br />

by the Operation Component Cooling<br />

System*.<br />

NPPs with Pressurized Heavy<br />

Water Reactor<br />

The function of the Moderator System<br />

in power operation of the plant<br />

requires identical pressure and<br />

temperature design values as <strong>for</strong> the<br />

Reactor Coolant System itself. However,<br />

this also opens up the possibility<br />

– by switching over valves inside<br />

the Moderator System and with an<br />

appropriate design of the RHR Intermediate<br />

Cooling System as the middle<br />

link of the RHRC – to take over the<br />

cooling of the reactor immediately<br />

after shut down, even without additional<br />

Steam Generator feed. This<br />

option has not yet been implemented<br />

<strong>for</strong> the MZFR as the first PHWR plant.<br />

Only CNA 1 and CNA 2 are equipped<br />

with a high pressure/high temperature<br />

designed RHRC and are there<strong>for</strong>e<br />

independent of the function of the<br />

main heat sink (steam turbine condenser)<br />

<strong>for</strong> cooling down the plant<br />

1<br />

2<br />

RCP<br />

5<br />

Reactor<br />

after all shut-down occasions to be<br />

assumed.<br />

Multi-purpose research reactor<br />

Karlsruhe (MZFR), 50 MWel<br />

The shutdown concept of the MZFR<br />

basically corresponds to that of PLWR<br />

plants, with priority on the Steam<br />

Generators [11]. Only when this –<br />

below a certain coolant temperature –<br />

is no longer thermodynamically<br />

possible, switch over to RHRC operation<br />

has to be per<strong>for</strong>med <strong>for</strong> further<br />

cooling of the plant. Moderator temperature<br />

and heat to be removed at<br />

this time are already so low that the<br />

SG<br />

From<br />

Condenser<br />

Cooling<br />

Tower<br />

RCP<br />

5<br />

RCP<br />

3<br />

5<br />

RCP<br />

3. Fuel Pool<br />

7 4 7 Cooler 7 4 7 4<br />

SG<br />

1<br />

Reactor<br />

4<br />

SG<br />

2 2<br />

G<br />

G<br />

6 6 Reactor<br />

6<br />

Building<br />

11<br />

Annulus<br />

11<br />

3a 3<br />

3<br />

3 3<br />

5a<br />

Emergency Feed<br />

Water System<br />

8 9 10<br />

Operational<br />

Cooling points<br />

Reactor Reactor<br />

Building Auxiliary<br />

Interior Building<br />

| Figure 6<br />

DWR 1300 MW, Reactor Coolant System and RHR Chain.<br />

Emergency Feed<br />

Water System<br />

10 9 8<br />

5<br />

1a<br />

6<br />

3a<br />

5a<br />

SG<br />

RCP<br />

1<br />

1<br />

10<br />

2<br />

Feedwater<br />

System<br />

5 7<br />

| Figure 7<br />

MZFR, Reactor Coolant System and RHR Chain.<br />

Emergency Feed<br />

Water System<br />

9 8<br />

G<br />

11<br />

Moderator Cooler on its secondary<br />

side can be operated with inlet<br />

temperatures, which are accepted by<br />

the other cooling points of the<br />

Component Cooling System without<br />

boiling at its outlet; even at the slight<br />

overpressure with which the Component<br />

cooling System is operated.<br />

A special feature of the MZFR-<br />

RHRC is that the operating pressure in<br />

the Secured Service Cooling Water is<br />

higher than in the system. In the event<br />

of a heat tube leak in the Component<br />

Cooling Heat Exchanger, transition<br />

of possibly radioactive contaminated<br />

water to the environment is thereby<br />

6<br />

Main Steam System<br />

Reactor Coolant System<br />

Residual Heat<br />

Removal System<br />

Safety Component<br />

Cooling System<br />

Secured Service<br />

Cooling Water System<br />

SG Steam Generator<br />

RCP Reactor Coolant Pump<br />

1 Residual Heat Removal Pumps<br />

1a Fuel Pool Cooling Pumps<br />

2 Residual Heat Exchangers<br />

3 Component Cooling Pumps<br />

3a Emergency Component<br />

Cooling Pumps<br />

4<br />

Operation Component<br />

Cooling System<br />

Component Cooling<br />

Heat Exchangers<br />

SG<br />

Main Steam System<br />

Reactor Coolant System<br />

Moderator System<br />

Component Cooling<br />

System<br />

Secured Service<br />

Cooling Water System<br />

Steam Generator<br />

RCP Reactor Coolant Pump<br />

1 Moderator Pumps<br />

2 Moderator Coolers<br />

3 Component Cooling Pump(s)<br />

4 Component Cooling<br />

Heat Exchanger<br />

5 Secured Service<br />

Cooling Water Pumps<br />

6 Further Component Cooling<br />

Water Consumers<br />

7 Further Secured Service<br />

Cooling Water Consumers<br />

5 Secured Service<br />

Cooling Water Pumps<br />

5a Emergency Secured Service<br />

Cooling Water Pumps<br />

6<br />

Safety-related Cooling Points<br />

7 Secured Intermediate Coolers<br />

8 Emergency Feed Water Pumps<br />

9 Emergency Generators<br />

10 Emergency Diesel Engines<br />

11 Demineralized<br />

Water Pool<br />

*With introduction of the<br />

new “<strong>Power</strong> Plant<br />

Labeling System (KKS)”<br />

in 1976 the Component<br />

Cooling System was,<br />

without any technical<br />

impact, split into “Safety<br />

Component Cooling<br />

System” and “Operation<br />

Component Cooling<br />

System”. The <strong>for</strong>mer<br />

includes the Component<br />

Cooling Pumps,<br />

the Component Cooling<br />

Heat Exchangers as<br />

well as the supply of all<br />

cooling points that are<br />

relevant <strong>for</strong> operation<br />

of the RHRC. The latter<br />

only consists of the<br />

connected pipe network,<br />

which distributes<br />

and collects the cooling<br />

water flows to consumers<br />

of nuclear<br />

operating systems<br />

inside Reactor- and<br />

Reactor Auxiliary<br />

Building.<br />


Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


RCP<br />

3<br />

SG<br />

Reactor<br />

SG<br />

RCP<br />

2 1<br />

1 2 Feed Water<br />

System<br />

3<br />

4 4<br />

5<br />

| Figure 8<br />

CNA 1, Reactor Coolant System and RHR Chain.<br />

3<br />

avoided, but pollution of the demineralized<br />

water in the component<br />

cooling circuit may happen instead. In<br />

subsequent plants, the pressure gradation<br />

was implemented consistently<br />

from the heat source (high) to the<br />

heat sink (low).<br />

NPP Atucha 1 (CNA 1),<br />

319 MWel<br />

The Moderator System consists of two<br />

completely separate loops, each of<br />

which assigned to a circuit of the RHR<br />

Intermediate Cooling System [12],<br />

[13], [14]. Deviating from MZFR, the<br />

task of this system is to be able to take<br />

6<br />

Main Steam System SG Steam Generator<br />

Reactor Coolant System RCP Reactor Coolant Pump<br />

1 Moderator Pumps<br />

Moderator System<br />

2 Moderator Coolers<br />

RHR Intermediate<br />

3 RHR Intermediate<br />

Cooling System<br />

Cooling Pumps<br />

Component Cooling<br />

4 RHR Intermediate<br />

System<br />

Cooling Heat Exchanger<br />

Secured Service<br />

Cooling Water System<br />

8<br />

7<br />

9<br />

5 Secured Service<br />

Cooling Water Pumps<br />

6 Component<br />

Cooling Pumps<br />

7 Component Cooling<br />

Heat Exchanger<br />

8<br />

Component Cooling<br />

Water Consumers<br />

9 Fuel Pool Coolers<br />

over the reactor cooling already<br />

shortly after shut down of the Reactor.<br />

The asso ciated temperature and<br />

pressure values ​in the system preclude<br />

the use of the Component Cooling<br />

System <strong>for</strong> heat removal; this is<br />

designed to only supply all other<br />

safety- related and the operational<br />

cooling points as a single circuit<br />

without redundancy. It is fitted out<br />

with two Component Cooling Heat<br />

Exchangers and Component Cooling<br />

Pumps of full capacity each. The<br />

RHR Intermediate Cooling System is<br />

equipped with a third RHR Intermediate<br />

Cooling Pump. In the event of<br />

failure of one of the two regular<br />

pumps this additional pump takes<br />

over the circulation in the affected<br />

circuit. The return lines of the RHR<br />

Intermediate Cooling Circuits cannot<br />

be shut off to the area around the<br />

Moderator Cooler flowed through by<br />

the feed water during power operation,<br />

so that the feed water pressure is<br />

impressed on them in their standby<br />

state. After the feed water lines at the<br />

outlet of the Moderator Cooler have<br />

been shut off and transition to the<br />

RHRC cycle operation is completed,<br />

the water balance in the RHR Intermediate<br />

Cooling Circuits (absorption<br />

of expansion water when heating up,<br />

recovery of contraction water when<br />

cooling down) can be carried out via<br />

expansion tanks as well as discharges<br />

to the Feed Water Tank on the one<br />

hand, and feed from the tank or the<br />

demineralized water pool by means of<br />

system-associated pumps on the other<br />

hand.<br />

A line assignment has not yet<br />

been made <strong>for</strong> the outer RHRC link,<br />

the Secured Service Cooling Water<br />

System. Three parallel Secured Service<br />

Cooling Water Pumps can feed a<br />

manifold, from which all inter coolers<br />

as well as the Fuel Pool Coolers are<br />

supplied.<br />

NPP Atucha 2 (CNA 2),<br />

692 MWel<br />

A clear line separation concept has<br />

been implemented at CNA 2. Although<br />

the plant only has two reactor cooling<br />

circuits, the Moderator System and<br />

the entire RHRC are constructed with<br />

four lines, each of them having a<br />

capacity of 50 % of the total power to<br />

| Figure 9<br />

CNA 2, Reactor Coolant System and RHR Chain.<br />

RCP Reactor Coolant Pump<br />

SG Steam Generator<br />

1<br />

2<br />

3<br />

4<br />

5<br />

6<br />

7<br />

8<br />

9<br />

10<br />

Moderator Pumps<br />

Moderator Coolers<br />

RHR Intermediate Cooling Pumps<br />

RHR Intermediate Cooling Heat Exchangers<br />

Secured Service Cooling Water Pumps<br />

Component Cooling Pumps<br />

Component Cooling Heat Exchangers<br />

Component Cooling Water Consumers<br />

Fuel Pool Coolers<br />

Secured Intermediate Coolers<br />

Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

be removed in the design case. Thus<br />

the “repair + single-failure” criterion<br />

<strong>for</strong> accidents is fulfilled. Not only the<br />

RHR Intermediate Cooling System,<br />

but also the Safety Component<br />

Cooling System here consists of four<br />

circuits, which supply the respective<br />

associated consumers – i. e. pumps<br />

and their motors – with cooling water.<br />

The circuits of the two outer re dundancies<br />

in Figure 9 can also be optionally<br />

switched on to cooling points of<br />

the fuel assembly transport devices<br />

(not shown in Figure 9). One circuit<br />

of the two inner redundancies serves<br />

not only its safety-relevant consumers,<br />

but also the Operation Component<br />

Cooling System, the other one stands<br />

by <strong>for</strong> that. The design of the RHR Intermediate<br />

Cooling System enables –<br />

if necessary – a takeover of heat transfer<br />

from the Reactor Cooling System<br />

after shut-down of the plant without<br />

the aid of Steam Generator feed. To<br />

achieve the maximum possible heat<br />

removal capacity, the bypasses inside<br />

the RHR Intermediate Cooling Circuit<br />

around Moderator Cooler and RHR<br />

Intermediate Cooling Heat Exchanger<br />

must be closed. If it is necessary <strong>for</strong><br />

the RHRC to keep the Reactor Cooling<br />

System at a desired temperature state<br />

or to cool it down according to a<br />

specified shutdown gradient, this is<br />

done by opening/ closing the bypass<br />

around the Moderator Cooler and<br />

by controlling the flow rate through<br />

the primary side of the RHR Intermediate<br />

Cooling Heat Exchanger on<br />

the one hand and the bypass around<br />

the cooler on the other (Shutdown<br />

control).<br />

An important modification compared<br />

to CNA 1 is the handling of the<br />

water balance in the RHR Intermediate<br />

Cooling Circuits. Facilities<br />

<strong>for</strong> absorbing expansion water and<br />

re-feeding it when the circuit cools<br />

down as well as replacing operational<br />

medium losses (in the event of failure<br />

of operational demineralized water<br />

supply) are set up <strong>for</strong> each circuit<br />

self-sufficient and spatially separated<br />

from each other in the Reactor<br />

Building Annulus.<br />

Each of the four subsystems of the<br />

Secured Service Cooling Water<br />

System with one Secured Service<br />

Cooling Water Pump each, supplies all<br />

of the assigned heat exchangers in<br />

parallel, that are<br />

p one RHR Intermediate Cooling<br />

Heat Exchanger,<br />

p one Component Cooling Heat<br />

Exchanger,<br />

p one Secured Intermediate Cooler,<br />

(This heat exchanger removes the<br />

Emergency Feed<br />

Water System<br />

1<br />

SG<br />

1a<br />

2<br />

RCP<br />

5<br />

heat loss from the line-assigned<br />

Emergency Diesel Engine and the<br />

Secured Chilled Water System,<br />

which is absorbed in the so-called<br />

Secured Closed Cooling Water<br />

System.)<br />

p One Fuel Pool Cooler (Each one of<br />

the two coolers is connected to two<br />

subsystems of the Secured Service<br />

Cooling Water System; this is why<br />

in Figure 9 and Figure 10 below –<br />

only to illustrate the supplyability –<br />

four pool coolers are drawn.)<br />

1<br />

5<br />

Reactor<br />

6 6<br />

Reactor<br />

Building 6<br />

6<br />

11<br />

Annulus<br />

11<br />

3a 3<br />

3<br />

3 3 3a<br />

3. Fuel Pool<br />

4 7 4 7 Cooler<br />

7 4 7 4<br />

5a<br />

Main Steam System<br />

Reactor Coolant System<br />

SG<br />

2<br />

RCP<br />

Residual Heat Removal System<br />

Safety Component Cooling System<br />

RCP<br />

5<br />

SG<br />

RCP<br />

2 2<br />

8 9 10 8 9 10<br />

10 9 8<br />

10 9 8<br />

11<br />

G<br />

Emergency Feed<br />

Water System<br />

G<br />

Operational<br />

Cooling Points<br />

Reactor Reactor<br />

Building Auxiliary<br />

Interior Building<br />

Comparison DWR 1300 MW –<br />

Atucha 2<br />

By comparing the RHRC configurations<br />

of the latest PLWR- and PHWR<br />

plants in Figure 10 it is intended to<br />

show at a glance their differences<br />

in the type and scope of process<br />

engineering equipment <strong>for</strong> the removal<br />

of residual heat from the<br />

reactor cooling system. Furthermore,<br />

it is marked which resp. how many<br />

subsystems/lines must be active<br />

during power operation of the plant.<br />

1<br />

G<br />

DWR 1300 MW<br />

Emergency Feed<br />

Water System<br />

5<br />

1a<br />

5a<br />

SG<br />

Operation Component Cooling System<br />

Secured Service Cooling Water System<br />

| Figure 10<br />

DWR 1300 MW – CNA 2, Comparison of RHR Chains regarding their necessary use during power operation of the plant;<br />

Explanation of Numbers: see Figures 6 and 9.<br />

1<br />

Emergency Feed<br />

Water System<br />

G<br />

11<br />

CNA 2<br />


Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


DWR 1300 MW<br />

Reactor SG<br />

CNA 2<br />

Reactor<br />

RCP<br />

SG<br />

RCP<br />

6<br />

3<br />

HPT<br />

FWT<br />

HPT<br />

4<br />

M<br />

S<br />

RH<br />

5<br />

M S<br />

LPT<br />

LPT<br />

G<br />

Main Cooling<br />

Water<br />

G<br />

G<br />

SG<br />

RCP<br />

RH<br />

Steam Systems<br />

Reactor Coolant System<br />

Moderator System<br />

Feedwater System<br />

Main Condensate System<br />

Main Cooling Water System<br />

Steam Generator<br />

Reactor Coolant Pump<br />

FWT Feed Water Tank<br />

HPT<br />

LPT<br />

MS<br />

1<br />

2<br />

3<br />

Generator<br />

Reheater<br />

High Pressure Turbine<br />

Low Pressure Turbine<br />

Moisture Separator<br />

Moderator Pump<br />

Moderator Cooler<br />

Main Feedwater Pump<br />

1 2<br />

FWT<br />

4<br />

3 5<br />

Main Cooling<br />

Water<br />

4<br />

5<br />

6<br />

Low-Pressure<br />

Feedwater Heater<br />

Main Condensate Pump<br />

High-Pressure<br />

Feedwater Heater<br />

| Figure 11<br />

DWR 1300 MW – CNA 2, Comparison of Water/Steam Cycles (simplified).<br />

In order to complete the comparison,<br />

the water/steam cycle must<br />

also be included. By using the<br />

Moderator Cooler <strong>for</strong> preheating the<br />

feed water, the PHWR – in this<br />

regard – is considerably simplified in<br />

comparison to the PLWR (Figure 11).<br />

In addition to the High Pressure<br />

Preheaters themselves, the steam<br />

extraction points on the high- pressure<br />

section of the Steam Turbine and the<br />

connecting steam pipes are eliminated<br />

<strong>for</strong> the PHWR.<br />

The second above item determines<br />

the number of pumps within the<br />

RHRC that are to be operated continuously,<br />

and thus also the electrical<br />

auxiliary power demand as well as the<br />

net efficiency.<br />

In Figure 10 mean:<br />

p Thick drawn subsystems and<br />

components: <br />

Used in power operation<br />

p Thin drawn subsystems and<br />

components:<br />

Operation readiness<br />

p Thin drawn heat exchanger edging,<br />

but with thick drawn flow symbol:<br />

Flow through its secondary side,<br />

but without heat input<br />

For DWR 1300 MW, the upper part<br />

of Figure 10 shows the minimum<br />

amount of subsystems to be operated.<br />

It is assumed that<br />

p the fuel pool cooling circuit<br />

connected to the Operating Component<br />

Cooling System is sufficient<br />

to maintain the fuel pool water<br />

under the desired temperature.<br />

Otherwise, one of the outer RHR<br />

lines would have to be operated<br />

with a Fuel Pool Cooling Pump,<br />

addi tionally or exclusively.<br />

p operation of only one of the four<br />

Secured Chilled Water Systems<br />

(which are redundantly supplied<br />

by the Secured Closed Cooling<br />

Water Systems) is necessary and<br />

there<strong>for</strong>e just one of the Secured<br />

Intermediate Coolers (No. 7 in<br />

Figure 6 and Figure 10 above) has<br />

to be flowed through. If this is not<br />

the case, then additional subsystems<br />

of the Secured Service<br />

Cooling Water System must be<br />

activated.<br />

With CNA 2, the constantly running<br />

Moderator Pumps mean that their<br />

cooling points – line-separated –<br />

always have to be supplied with cooling<br />

water via the Safety Component<br />

Cooling System. There<strong>for</strong>e, all its<br />

subsystems as well as the entire<br />

Secured Service Cooling Water S ystem<br />

must continuously be operated. With<br />

regard to the heat removal capacity,<br />

actually only the line which is connected<br />

to the Operation Com ponent<br />

Cooling System with its permanent<br />

heat input is utilized, fully or only<br />

partially.<br />

The part of the RHR Intermediate<br />

Cooling System not flowed by feed<br />

water is separated and in stand-by<br />

condition.<br />

In contrast to the DWR 1300 MW,<br />

the fuel pool cooling in CNA 2 is<br />

completely independent from the heat<br />

removal via the RHRC. Here, the fuel<br />

pool cooling circuits transfer the heat<br />

to be removed directly to the Secured<br />

Service Cooling Water.<br />

Summary<br />

Development of the Residual Heat<br />

Removal Chain (RHRC) in NPPs with<br />

Pressurized Water Reactors of german<br />

design, from the prototype plant<br />

MZFR (heavy water) and the<br />

demonstration power plant KWO<br />

(light water) to the last plants erected,<br />

was carried out on three mutually<br />

independent areas:<br />

p PLWR and PHWR:<br />

Increasing requirements concerning<br />

plant-internal damage<br />

assumptions<br />

The assumption of failing of passive<br />

components and system parts<br />

as well as the postulate of simultaneity<br />

of “repair case and single<br />

failure” led to the (step- by-step)<br />

Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

P transition from the single-line<br />

to the multi-line RHRC-design<br />

with several functionally independent<br />

redundancies of the<br />

same heat transfer capacity. In<br />

plants with four RHR lines – as<br />

is the case with the DWR<br />

1300 MW class as well as with<br />

Atucha 2 – each of the lines has<br />

to be equipped with a heat<br />

removal capacity of 50 %, based<br />

on the thermodynamic design<br />

case of the entire RHRC.<br />

P This goes hand in hand with<br />

abandoning meshing technology<br />

in which, <strong>for</strong> example, if<br />

a pump fails, a reserve unit<br />

can be switched to various<br />

subsystems of an RHR link.<br />

p PLWR – specific:<br />

Measures <strong>for</strong> emergencies “civilization-related<br />

external impacts”<br />

For the first time after the occurrence<br />

of accidents, in which it is no<br />

longer possible to feed the Steam<br />

Generators from the Feed Water<br />

Tank, the Emergency Feed Water<br />

System was created to remove the<br />

residual heat via Steam Generators,<br />

<strong>for</strong> the long-term range via<br />

the Emergency Cooling Chain<br />

(ECC) Chain, both of them operated<br />

by self-sufficient diesel engines/<br />

generators. According to the safety<br />

requirements two Emergency<br />

Cooling Lines of a thermal capacity<br />

of 100 % each, with respect to the<br />

max. power to be removed, are<br />

sufficient. For this ECC, sub systems<br />

of the middle link (Safety Component<br />

Cooling System) and the<br />

outer link (Secured Service<br />

Cooling Water System) of the<br />

existing RHRC are equipped with<br />

additional, less powerful pumps –<br />

parallel to the main pumps. By<br />

using this two lines as ECC which<br />

contain a Fuel Pool Cooling Pump<br />

in their inner link, this aggregates<br />

are also deployed as “emergency<br />

residual heat removal pumps”.<br />

Both the Reactor and the Fuel Pool<br />

can thus be cooled via these lines.<br />

p PHWR – specific :<br />

Transition to a high-pressure/<br />

high-temperature RHRC<br />

The residual heat removal concept<br />

of the MZFR as the first plant of this<br />

type of NPPs is largely identical<br />

with that from PLWR. In the first<br />

time after Reactor shut-down<br />

cooling is per<strong>for</strong>med exclusively<br />

via the secondary side (Steam<br />

Generator) be<strong>for</strong>e the RHRC takes<br />

over with the Moderator System<br />

as the inner link. Only in the<br />

sub sequent plants Atucha 1 and<br />

Atucha 2 the fact has been utilized,<br />

that with the Moderator System a<br />

“ Residual Heat Removal System” is<br />

available, which is similar to the<br />

Reactor Cooling System regarding<br />

its pressure/temperature design<br />

values. By also designing the<br />

middle RHR link, the RHR Intermediate<br />

Cooling System, as highpressure/high-temperature<br />

circuits<br />

it was possible to create a divers<br />

residual heat removal option <strong>for</strong><br />

the Steam Generators, with which<br />

reactor cooling is possible from the<br />

beginning – without further Steam<br />

Generator feeding.<br />

Bibliography<br />

[1] Lepie, G., Martin, A.<br />

“Aufbau der Gesamtanlage KWO”<br />

Atomwirtschaft, December 1968<br />

P. 596 – 606<br />

[2] Kernkraftwerk Stade<br />

“Tabelle: Wichtige Daten des Kernkraftwerks Stade”<br />

Atomwirtschaft, November 1971<br />

P. 586 – 590<br />

[3] Müller, H., Stahlschmidt, H.<br />

“Die Gesamtanlage des Kernkraftwerks Stade”<br />

Atomwirtschaft, November 1971<br />

P. 579 – 580<br />

[4] Bruhn, H.<br />

“Reaktorhilfs- und Nebenanlagen des KKS”<br />

Atomwirtschaft, November 1971<br />

P. 610 – 612<br />

[5] Huttach, A., Putschögl, G., Ritter, M.<br />

“Die Nuklearanlage des Kernkraftwerks Biblis”<br />

Atomwirtschaft, August/September 1974<br />

P. 420 – 430<br />

[6] Bald, A., Brix, O.<br />

“Die Dampfkraftanlage des Kernkraftwerks Biblis”<br />

Atomwirtschaft, August/September 1974<br />

P. 431 – 438<br />

[7] “RSK-Leitlinien für Druckwasserreaktoren”<br />

Original version (3 rd edition of October 14, 1981)<br />

with amendments of November 15, 1996<br />

[8] Sicherheitstechnische Regel des KTA<br />

“KTA 3301, Nachwärmeabfuhrsysteme<br />

für Leichtwasserreaktoren”<br />

Version 2015-11<br />

[9] Sicherheitstechnische Regel des KTA<br />

“KTA 3303, Wärmeabfuhrsysteme für Brennelementlagerbecken<br />

von Kernkraftwerken mit Leichtwasserreaktoren”<br />

Version 2015-11<br />

[10] Rieser, R., Brosche, D., Faber, P.<br />

“Planung, Errichtung und Inbetriebnahme<br />

des Konvoi-Leitprojektes Isar-2”<br />

Atomwirtschaft, June 1988<br />

P. 276 – 284<br />

[11] Bald, A., Schamburger, R.<br />

“Die Dampfkraftanlage”, from “MZFR Kernkraftwerk<br />

mit Mehrzweck-D2O-Druckkesselreaktor in Karlsruhe”<br />

Atomwirtschaft, July/August 1965<br />

P. 363 – 368<br />

[12] Frewer, H., Keller, W.<br />

“Das 340-MW-Kernkraftwerk Atucha<br />

mit Siemens-Natururan-Druckwasserreaktor”<br />

Atomwirtschaft, July 1968<br />

P. 350 – 358<br />

[13] Herzog, G., Sauerwald, K.-J.<br />

“Das Kernkraftwerk Atucha”<br />

Changed reprint from ATOM und STROM, 15 th Year,<br />

issue 4, April 1969<br />

P. 53 – 63<br />

[14] Hirmer, G., Seifert, W.<br />

“Das Kernkraftwerk Atucha”<br />

Elektrotechnische Zeitschrift,<br />

Ausgabe A (ETZ-A), Band 90, (1969)<br />

P. 509 – 513<br />

Authors<br />

Franz Stuhlmüller<br />

External Scientific<br />

Associate at the Chair of<br />

<strong>Nuclear</strong> Technology at<br />

the Technical University<br />

of Munich<br />

f-stuhlmueller@<br />

t-online.de<br />

Franz Stuhlmüller studied Mechanical Engineering at<br />

the Rudolf-Diesel-Polytechnikum in Augsburg as well<br />

as Energy and <strong>Power</strong> Plant Technology at the Technical<br />

University of Munich. He was employed at Kraftwerk<br />

Union / Siemens AG in Erlangen in the field of nuclear<br />

power plants as well as conventional power plant<br />

technology. As a section manager he was responsible<br />

<strong>for</strong> decay power calculation and design of nuclear<br />

safety systems, conventionally <strong>for</strong> the development of<br />

advanced coal-fired combined cycle power plants as<br />

well as new emerging power generation technologies.<br />

After he retired in 2007 he was a consultant during<br />

completion of the Heavy Water <strong>Nuclear</strong> <strong>Power</strong> Plant<br />

Atucha 2 in Argentina till 2015. Since 2016 Franz is an<br />

External Scientific Associate at the Chair of <strong>Nuclear</strong><br />

Technology at the Technical University of Munich<br />

(TUM).<br />

Prof. Rafael<br />

Macián-Juan, PhD<br />

Head of the Chair<br />

of <strong>Nuclear</strong> Technology<br />

at the Technical<br />

University of Munich<br />

rafael.macian@<br />

ntech.mw.tum.de<br />

Prof. Rafael Macián-Juan has a Master of Science in<br />

Energy Engineering from the Polytechnic University of<br />

Valencia, Spain, as well as a Master of Science in<br />

<strong>Nuclear</strong> Technology and holds an PhD in <strong>Nuclear</strong><br />

Technology by the Penn State University, USA. He is<br />

the Head of the Chair of <strong>Nuclear</strong> Technology since<br />

2007 at the Technical University of Munich (TUM).<br />

Be<strong>for</strong>e joining TUM, he worked at the Paul Scherrer<br />

Institute (PSI), Switzerland, where he carried out<br />

research and development in reactor thermalhydraulics<br />

and coupled neutronics, as well as safety<br />

assessments of the Swiss nuclear power plants. His<br />

current research interests include nuclear safety,<br />

multi-physics and multiscale simulation codes,<br />

uncertainty and sensitivity methods, experimental and<br />

numerical thermal-hydraulics, and safety analysis and<br />

development of future nuclear reactor designs. He is<br />

currently also visiting professor at Harbin Engineering<br />

University in China.<br />


Environment and Safety<br />

Safety-related Residual Heat Removal Chains of German Technology Pressure Water Reactors (Light and Heavy Water) ı Franz Stuhlmüller and Rafael Macián-Juan

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


IAEA Approach to Review the<br />

Applicability of the Safety Standards<br />

to Small Modular Reactors<br />

Paula Calle Vives, Kristine Madden and Vesselina Ranguelova<br />

Introduction A continuously increasing interest in nuclear power, and particularly in small modular reactor (SMR)<br />

technologies, has been expressed over the past several years by numerous IAEA Member States particularly in<br />

contributing to the mitigation of climate change. Today there are over seventy (70) SMR designs under development<br />

according to the IAEA booklet Advances in Small Modular Reactor Technology Developments, a Supplement to IAEA<br />

Advanced Reactors In<strong>for</strong>mation System (ARIS) [5]. While SMRs are typically designed to generate electric power up to<br />

300 MW, many new designs are also designed <strong>for</strong> other heat production applications, such as district heating,<br />

desalination and hydrogen production or a combination of the <strong>for</strong>mer.<br />

SMRs present novel features and<br />

innovative technologies, including<br />

different types of coolant, nuclear fuel<br />

and neutron spectrums and inherent<br />

safety features. As <strong>for</strong> all reactors,<br />

SMRs shall meet the objective of<br />

ensuring the protection of people and<br />

the environment from the harmful<br />

effects of ionizing radiation. A key<br />

element of meeting this objective<br />

is demonstrating compliance with<br />

fundamental safety principles and<br />

safety requirements.<br />

The IAEA safety standards reflect a<br />

widely accepted extensive approach<br />

to ensure nuclear safety, establishing<br />

safety principles, requirements and<br />

associated guidance. The IAEA safety<br />

standards are Member States consensus<br />

based documents that have<br />

been developed in an iterative fashion<br />

and capture wider aspects of legal,<br />

regulatory, siting, design, construction,<br />

commissioning, operation, decommissioning,<br />

and release from<br />

regulatory control of nuclear facilities<br />

and radioactive waste management,<br />

including disposal. Although the IAEA<br />

safety standards are considered to<br />

be technology neutral, they are influenced<br />

by specific issues pertaining to<br />

water cooled large reactors technology<br />

as most of the experience and<br />

knowledge in the Member States<br />

contributing to the development of<br />

safety standards is based predominantly<br />

the existing technology.<br />

In recent years, the IAEA has<br />

undertaken various initiatives to<br />

review the applicability of certain<br />

safety standards to particular types of<br />

SMRs. Until now, however, the IAEA<br />

has not systematically assessed the<br />

applicability of the IAEA safety<br />

standards to all types of SMRs<br />

through out their entire lifecycle.<br />

There<strong>for</strong>e, the IAEA has developed<br />

and is implementing an approach <strong>for</strong><br />

the identification of areas of nonapplicability<br />

of the IAEA safety<br />

standards, to suggest compensatory<br />

measures to close any identified gaps,<br />

in order to address the needs of the<br />

Member States.<br />

The Early Work<br />

The current approach adopted by the<br />

IAEA builds on the early work<br />

per<strong>for</strong>med <strong>for</strong> the preparation of the<br />

IAEA in TecDoc-1936 [1] establishing<br />

the engineering judgement necessary<br />

to apply the design safety requirements<br />

contained in SSR-2/1 (Rev. 1)<br />

[2] to light water cooled and<br />

high temperature gas cooled SMRs<br />

(LW-SMRs and HTG-SMRs).<br />

A team of international experts<br />

between 2016 and 2018 (see<br />

TecDoc-1936 [1], pg 144-145 ) was<br />

asked by the IAEA to per<strong>for</strong>m a pilot<br />

study to assess, with comments, the<br />

applicability of SSR-2/1 (Rev. 1) [2] to<br />

the a<strong>for</strong>ementioned SMR tech nologies<br />

on the basis of the following criteria:<br />

p Applicable as is<br />

p Applicable with modification<br />

p Applicable with interpretation<br />

p Not applicable<br />

The participants were also encouraged<br />

to include any recommendations<br />

<strong>for</strong> new criteria not covered in SSR-<br />

2/1 (Rev. 1) [2] and to provide technical<br />

rationale <strong>for</strong> their recommendations.<br />

Applicable with modification<br />

inferred the need <strong>for</strong> the text to be<br />

updated <strong>for</strong> the requirement to be<br />

applicable to the specific design,<br />

whereas applicable with interpretation<br />

inferred the need to modify<br />

definitions of pre-existing terminology<br />

to encompass the new technologies.<br />

The Member States’ contributions<br />

were merged and refined<br />

into one comprehensive working<br />

document to provide an overarching<br />

list of recommendations. The creation<br />

of this working document highlighted<br />

the need <strong>for</strong> the two SMR designs<br />

assessed to initially be discussed<br />

independently in reference to their<br />

applicability to SSR-2/1 (Rev. 1) [2].<br />

The working document, in its final<br />

<strong>for</strong>m, evaluated the applicability of<br />

each of the 82 design safety requirements<br />

established in SSR-2/1 (Rev. 1)<br />

[2] to LW-SMRs and HTG-SMRs. The<br />

initial findings from the LW-SMR<br />

working group were presented and<br />

published at an international IAEA<br />

conference in 2017 [4]. The working<br />

material developed in this manner<br />

was channelled into an evolving project<br />

report that <strong>for</strong>ms the basis of<br />

Appendixes I and II and Annex I in<br />

IAEA TecDoc-1936 [1]. The IAEA<br />

officers responsible <strong>for</strong> the development<br />

of this pilot study report were<br />

Kristine M.. Madden and Ramsey<br />

Arnold of the Division of <strong>Nuclear</strong><br />

Installation Safety IAEA. The results<br />

of the study were subsequently extensively<br />

used to prepare an IAEA official<br />

publication. The work was completed<br />

by a team of international experts (see<br />

TecDoc-1936 [1], pg 143) with IAEA<br />

responsible officer Palmiro Villalibre<br />

Ares of the Division of <strong>Nuclear</strong> Installation<br />

Safety in the <strong>for</strong>m of<br />

TecDoc-1936 [1].<br />

Current applicability review<br />

approach<br />

The ongoing review of applicability of<br />

the safety standards builds on previous<br />

experiences and aims to consider<br />

in a holistic manner whether the<br />

current requirements and recommendations<br />

<strong>for</strong> SMRs cover the safety<br />

issues related to the new possibilities<br />

opened by the novel designs or, on the<br />

contrary, if there are gaps that need to<br />

be addressed to ensure that the level<br />

of safety established by the IAEA<br />

fundamental safety principles will be<br />

complied with.<br />

The level of safety defined by the<br />

Safety Objective and the Safety<br />

Fundamentals [6] is considered as the<br />

departing point <strong>for</strong> the study. The<br />

review there<strong>for</strong>e focuses only on<br />

the applicability of the requirements<br />

and recommendations to meet the<br />

Environment and Safety<br />

IAEA Approach to Review the Applicability of the Safety Standards to Small Modular Reactors ı Paula Calle Vives, Kristine Madden and Vesselina Ranguelova

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

overall high level of safety defined in<br />

the Fundamental Safety Principles:<br />

Safety Fundamentals (SF-1) [6].<br />

It is also expected that key elements<br />

of the safety design approach remain<br />

applicable to these technologies<br />

although additional guidance in the<br />

implementation may be necessary,<br />

such as<br />

p Defence in depth<br />

p The elimination of high radiation<br />

doses to workers<br />

p The practical elimination of early<br />

release<br />

It is also important to clarify that the<br />

scope of some SSGs may be wider than<br />

the scope of the safety requirements.<br />

These SSGs reflect the best practices in<br />

Member States. The lack of linkage<br />

with safety requirements may lead to<br />

additional consideration on how to<br />

define the design objectives in terms of<br />

acceptability of the consequences of<br />

novel accident scenarios.<br />

To achieve this objective, the<br />

review approach follows four steps<br />

that are presented in detail in this<br />

publication to identify:<br />

p the relevant safety standards to be<br />

considered in the review<br />

p areas of novelty when compared to<br />

operating land-based water-cooled<br />

large reactors<br />

p gaps in the applicability of the<br />

safety standards to SMRs, based on<br />

the areas of novelty identified.<br />

p areas of where the safety standards<br />

may not be applicable or could be<br />

adapted <strong>for</strong> a better application<br />

to novel design to some SMRs,<br />

based on the areas of novelty<br />

identified.<br />

Identification of the relevant<br />

safety areas to be considered<br />

in the review<br />

The safety areas and topics considered<br />

in the applicability review are presented<br />

in the table.<br />

Identification of areas<br />

of novelty<br />

The first step of the applicability<br />

review is the identification of areas of<br />

novelty in the lifecycle of the SMR<br />

when compared with land based<br />

water- cooled large reactors.<br />

The technologies considered as<br />

part of the review include transportable<br />

SMR, micro-sized reactors water<br />

cooled SMRs, and non-water SMRs<br />

(sodium fast reactors, lead fast reactors,<br />

high temperature gas cooled reactors,<br />

molten salt reactors).<br />

The identification of areas of novelty<br />

is based on a systematic comparison<br />

of the characteristics of SMRs with a<br />

Light-water Cooled Reactor Reference<br />

defined as part of the project.<br />

The characterization of these<br />

technologies in terms of areas of<br />

novelty is developed at the onset<br />

based on expert knowledge, literature<br />

review and detailed questionnaires<br />

responses by technology developers,<br />

reflecting designers’ current practices<br />

and claims. This in<strong>for</strong>mation is then<br />

reviewed by regulatory authorities,<br />

technical support organisations and<br />

Safety Areas<br />

Siting<br />

Design and<br />

Construction<br />

Fuel Cycle<br />

Waste<br />

Management<br />

Facilities and<br />

Decommissioning<br />

Safety<br />

Assessment<br />

Operation and<br />

Commissioning<br />

LMfS<br />

Legal and<br />

Regulation<br />

Safety Topics<br />

other organisations from member<br />

states participating in the project.<br />

Identification of gaps in the<br />

applicability of the safety<br />

standards to identified areas<br />

of novelty<br />

The areas of novelty identified are<br />

compared to the contents of the<br />

IAEA safety standards in terms of<br />

Site Evaluation <strong>for</strong> <strong>Nuclear</strong> Installations<br />

p Site survey and site selection<br />

p Consideration of external events in site evaluation <strong>for</strong> NPPs<br />

p Dispersion of radioactive material in site evaluation <strong>for</strong> NPPs<br />

Safety in Design <strong>for</strong> NPPs<br />

p Safety classification<br />

p The design of key reactor safety systems: the reactor core, the containment and associated systems and<br />

the reactor coolant system and associated systems<br />

p The design of electrical power systems<br />

p Instrumentation and control systems<br />

p The design of fuel handling and storage systems <strong>for</strong> NPPs<br />

p The application of the human factors engineering in the design<br />

p External hazards in the design<br />

p Internal hazards<br />

p Radiation protection and radioactive waste management<br />

p Construction <strong>for</strong> nuclear installations<br />

Safety of <strong>Nuclear</strong> Fuel Cycle Facilities<br />

p Safety of conversion facilities and uranium enrichment facilities<br />

p Safety of uranium fuel fabrication facilities<br />

p Safety of uranium and plutonium mixed oxide fuel fabrication facilities<br />

p Safety of nuclear fuel reprocessing facilities<br />

p Safety of nuclear fuel cycle research and development facilities<br />

p Criticality safety in the handling of fissile material<br />

Predisposal Management of Radioactive Waste and Decommissioning<br />

p Disposal of radioactive waste<br />

p Classification of radioactive waste<br />

p The safety case and safety assessment <strong>for</strong> the predisposal management of radioactive waste<br />

p Leadership, management and culture <strong>for</strong> safety in radioactive waste management<br />

p Predisposal management of radioactive waste from NPPs and research reactors<br />

p Storage of radioactive waste<br />

p The safety case and safety assessment <strong>for</strong> the disposal of radioactive waste.<br />

p Geological disposal of radioactive waste<br />

p Near surface disposal of radioactive waste<br />

p Decommissioning of nuclear power plants, research reactors and other nuclear fuel cycle facilities<br />

p Release of sites from regulatory control on termination of practices<br />

p Storage of spent fuel pool<br />

Safety Assessment <strong>for</strong> Activities and Facilities<br />

p The structure and content of the safety analysis report<br />

p The development and application to nuclear power plants of deterministic safety analysis and probabilistic<br />

safety analysis<br />

p The conduct of a periodic safety review (PSR) <strong>for</strong> an existing nuclear power plant<br />

Commissioning and Operations<br />

p Commissioning<br />

p Conduct of operations at nuclear power plants<br />

p Operational limits and conditions and operating procedures <strong>for</strong> nuclear power plants<br />

p Fire safety in the operation of nuclear power plants<br />

p Maintenance, surveillance and in-service<br />

p Modifications to nuclear power plants<br />

p Core management and fuel handling <strong>for</strong> nuclear power plants and criticality safety in the handling of<br />

fissile material<br />

p Operating experience feedback <strong>for</strong> nuclear installations<br />

p Ageing management and development of a programme <strong>for</strong> long term operation of nuclear power plants<br />

p Chemistry programme <strong>for</strong> water cooled nuclear power plants<br />

p The evaluation of seismic safety <strong>for</strong> nuclear installations<br />

p Accident management programme <strong>for</strong> a NPP<br />

Leadership and Management <strong>for</strong> Safety (LMfS)<br />

p The operating organization<br />

p The recruitment, qualification and training<br />

p The application of management systems to facilities<br />

p The management system <strong>for</strong> nuclear installations<br />

p Establishing the safety infrastructure <strong>for</strong> a nuclear power programme<br />

Legal and Regulation<br />

p Organisation etc. <strong>for</strong> regulatory body<br />

p Functions and processes of the regulatory body<br />

p Licensing process <strong>for</strong> nuclear installations regulatory control of radiactive discharges to the environment<br />


Environment and Safety<br />

IAEA Approach to Review the Applicability of the Safety Standards to Small Modular Reactors ı Paula Calle Vives, Kristine Madden and Vesselina Ranguelova

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


requirements and recommendations.<br />

Gaps in the safety standards may be<br />

associated to one or several of the following<br />

areas of novelty:<br />

p New barriers, new safety functions<br />

or new provisions to deliver the<br />

safety functions.<br />

p New failure mechanisms, faults,<br />

phenomena that could lead to the<br />

failure of a barrier or a provision to<br />

deliver a safety function.<br />

p Eliminated failure modes, faults,<br />

phenomena by design which<br />

may imply the need <strong>for</strong> additional<br />

design requirements and/or<br />

recommendations.<br />

p The use of new technologies,<br />

including new fuels, new coolants,<br />

novel safety provisions, novel<br />

materials and construction/manufacturing<br />

techniques that could<br />

lead to the need <strong>for</strong> additional<br />

requirements and/or recommendations<br />

(e.g. recommendations <strong>for</strong><br />

fuel qualification, qualification of<br />

materials to higher temperatures,<br />

use of more corrosive coolants, etc.)<br />

p New operating, maintenance,<br />

testing, refuelling and/or wates<br />

management strategies.<br />

p New facilities and/or activities on<br />

site and/or off site needed to support<br />

the construction, ope ration<br />

and/or post-operation management<br />

of the nuclear power plant.<br />

To ensure exhaustivity, <strong>for</strong> each of the<br />

above areas, the potential gaps are<br />

closely examined to judge if existing<br />

requirements and recommendations<br />

are sufficiently overarching to address<br />

the specific differences. In some cases,<br />

additional and more detailed review<br />

may be necessary at a later stage to<br />

characterise and confirm the identified<br />

potential gaps.<br />

Identification of areas where<br />

the safety standards may not<br />

be applicable to (some) areas<br />

of novelty<br />

The areas of novelty identified are<br />

then compared to the requirements<br />

and recommendation in the safety<br />

standards. Areas of non-applicability<br />

in the safety standards may be associated<br />

to one or several of the following<br />

novelties:<br />

p Failure modes, faults, phenomena<br />

typically considered in light-water<br />

cooled reactor reference that are<br />

not relevant to the design, which<br />

may imply some requirements<br />

and/or recommendations may not<br />

be applicable<br />

p Safety functions and provisions to<br />

deliver these functions that are no<br />

longer needed which may imply<br />

some requirements and/or recommendations<br />

may not be applicable<br />

p New operating, maintenance,<br />

testing, refuelling and/or postoperation<br />

management strategies<br />

which may imply some requirements<br />

and/or recommendations<br />

may not be applicable<br />

When areas of non-applicability are<br />

identified, the review also considers:<br />

p If there are associated gaps (not<br />

identified in the gap review)<br />

p If there is sufficient experience to<br />

confirm that the relevant areas<br />

of the safety standards are not<br />

applicable. In some cases, claims<br />

may have not been confirmed by<br />

sufficient operating experience or<br />

there are still considerable uncertainties<br />

related to the areas of<br />

novelty. For these cases additional<br />

features may be needed in the<br />

design until sufficient experience is<br />

available. The potential nonapplicability<br />

and uncertainty will<br />

be captured in the review.<br />

Expected outcomes<br />

The IAEA expects to publish this work<br />

as a Safety Report providing a roadmap<br />

<strong>for</strong> the applicability of the IAEA<br />

safety standards to novel advanced<br />

reactors and particularly SMRs<br />

throughout their entire lifecycle. The<br />

large team of IAEA experts and international<br />

experts from member states<br />

supporting the development and implementation<br />

of the presented<br />

approach will be acknowledged in the<br />

Safety Report publication.<br />

As a secondary outcome, it may be<br />

possible to further analyse gaps and<br />

areas of non-applicability to identify<br />

potential pathways <strong>for</strong> resolution and<br />

help to build a further programme<br />

of work to address areas of nonapplicability<br />

and potential gaps.<br />

References<br />


Design Safety Requirements to Small Modular Reactor<br />

Technologies Intended <strong>for</strong> Near Term Deployment: Light Water<br />

Reactors and High Temperature Gas Cooled Reactors, IAEA<br />

Technical Document No. 1936, IAEA, Vienna (2021).<br />

[2] INTERNATIONAL ATOMIC ENERGY AGENCY, Safety of <strong>Nuclear</strong><br />

<strong>Power</strong> Plants: Design, IAEA Safety Standards Series No.<br />

SSR-2/1 (Rev. 1), IAEA, Vienna (2016).<br />


Glossary: Terminology Used in <strong>Nuclear</strong> Safety and Radiation<br />

Protection (2007 Edition), IAEA, Vienna (2007).<br />

[4] K. Madden et al. “Applicability of IAEA Safety Standard SSR-<br />

2/1 to Water Cooled Small Modular Reactors”. Proceedings of<br />

an <strong>International</strong> Conference organized by the <strong>International</strong><br />

Atomic Energy Agency held in Vienna, 6 – 9 June 2017:<br />

Topical Issues in <strong>Nuclear</strong> Installation Safety: Safety<br />

Demonstration of Advanced Water Cooled <strong>Nuclear</strong> <strong>Power</strong><br />

Plants, V2. IAEA, Vienna (2018).<br />


Modular Reactor Technology Developments, a Supplement to<br />

IAEA Advanced Reactors In<strong>for</strong>mation System (ARIS), IAEA<br />

Booklet, 2020 Edition, IAEA, Vienna (2020).<br />


Safety Principles, IAEA, Vienna (2006).<br />

Authors<br />

Paula Calle Vives<br />

(Lead Author)<br />

Senior <strong>Nuclear</strong><br />

Safety Officer<br />

<strong>International</strong> Atomic<br />

Energy Agency<br />

P.Calle-Vives@iaea.org<br />

Paula Calle Vives is a Senior <strong>Nuclear</strong> Safety Officer at the<br />

IAEA and the Lead of SMRs and other cross cutting topics<br />

at the Safety Assessment Section. She chairs the IAEA<br />

Working Group on SMR Safety and leads the review of<br />

applicability of the IAEA Safety Standards to novel<br />

advanced reactors. Previously, she was the Delivery Lead<br />

of Advanced <strong>Nuclear</strong> Technologies at the Office <strong>for</strong><br />

<strong>Nuclear</strong> Regulation (ONR), UK. As a Principal Inspector,<br />

she also undertook roles on regulation of new build and<br />

operating reactors. Be<strong>for</strong>e ONR, she was a Senior Safety<br />

Engineer working in UK operating reactors, and<br />

developed proba bilistic safety analysis research in France.<br />

Paula holds a double nuclear engineering master’s degree<br />

(Universidad Politécnica de Madrid and Ecole Centrale de<br />

Nantes) as well as an international relations master’s<br />

degree (University of Cambridge).<br />

Kristine Madden<br />

Associate <strong>Nuclear</strong><br />

Safety Officer<br />

<strong>International</strong> Atomic<br />

Energy Agency<br />

K.Madden@iaea.org<br />

Kristine Madden is a creative and results driven nuclear<br />

industry leader with over ten years of progressive leadership<br />

experience across a broad range of diverse industry<br />

segments, including deterrence, non-proliferation, nuclear<br />

safety, nuclear security and nuclear energy. Kristine is currently<br />

a <strong>Nuclear</strong> Safeguards Inspector at the Inter national<br />

Atomic Energy Agency (IAEA), where she also previously<br />

worked on SMR and emergency response initiatives<br />

within the Department <strong>for</strong> <strong>Nuclear</strong> Safety and Security.<br />

Prior to joining the IAEA, she led licensing initiatives <strong>for</strong><br />

the Chernobyl ISF-2 project <strong>for</strong> Holtec <strong>International</strong> and<br />

was a Senior Reactor Operator, INPO Engineering Coordinator<br />

and Reactor Engineer at USA based nuclear power<br />

plants. Kristine is completing her master’s degree in <strong>International</strong><br />

Relations at the University of Cambridge and<br />

holds a bachelor’s degree in nuclear engineering and<br />

radiological sciences from the University of Michigan.<br />

Vesselina Rangelova<br />

Safety Assessment<br />

Section Head<br />

<strong>International</strong> Atomic<br />

Energy Agency<br />

V.Ranguelova@iaea.org<br />

Vesselina is the Head of the Safety Assessment Section, Department<br />

of Safety and Security at the <strong>International</strong> Atomic<br />

Energy Agency, managing the IAEA activities on design<br />

safety and safety assessment of nuclear power plants.<br />

Previously, she led the IAEA Operational Safety Review<br />

Team (OSART) to assess operational safety of <strong>Nuclear</strong><br />

<strong>Power</strong> Plants in IAEA Member States. Be<strong>for</strong>e joi ning the<br />

IAEA, she was coordinating the implementation of the<br />

European Commission Joint Research Centre EURATOM<br />

research and training programme on nuclear safety and<br />

security. Vesselina holds a master of science degree in<br />

nuclear engineering from Moscow <strong>Power</strong> Engineering University<br />

and post graduate diploma in probabilistic safety<br />

assessment techniques from Manchester University.<br />

Environment and Safety<br />

IAEA Approach to Review the Applicability of the Safety Standards to Small Modular Reactors ı Paula Calle Vives, Kristine Madden and Vesselina Ranguelova

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

A Zero-power Facility as a Multi-fold<br />

Opportunity to Support Quick Progress<br />

in Innovative Reactor Development<br />

Bruno Merk, Dzianis Litskevich, Anna Detkina, Greg Cartland-Glover, Seddon Atknison and Mark Bankhead<br />

Introduction and history <strong>Nuclear</strong> has a very unique role to play in a sustainable energy future, since it is the<br />

only currently available technology which can assure 24/7 availability and controllability while delivering massive<br />

amounts of low carbon energy on demand <strong>for</strong> a net-zero future. However, in the recent decades there has not been any<br />

significant progress in the development of viable innovative nuclear technologies in comparison with the golden age of<br />

the nuclear development (1950’s-1970’s). Most new designs are iterative improvements of the nuclear technologies<br />

developed at that time (e. g. EPR in France, BN in Russia), or are more radical designs with little substantiation with an<br />

exception made <strong>for</strong> BREST-OD-300 [1], currently under development/construction [2]. Regardless of the different<br />

nuclear technologies studied and developed, the majority of the NPPs built around the world are still light water<br />

reactors. Un<strong>for</strong>tunately, light water reactor technologies have their limits due to their operational characteristics and<br />

cannot address major challenges which nuclear industry faces at the moment. Core points are: reducing nuclear waste,<br />

the availability of resources to manage assets over 100’s years and the complexity systems leading to elevated cost. To<br />

be accepted by both, business and public, nuclear must deliver and be cost competitive compared to other flexible,<br />

on-demand producing, power plants with similar financial risks applied. Thus, nuclear needs innovations to be more<br />

sustainable, but even more importantly, we need to regrow the trust that nuclear can deliver these innovations. Finally,<br />

we need innovative approaches to reduce the risks associated with nuclear power plant construction becoming complex<br />

mega projects.<br />

59<br />


Looking back to the most recent<br />

western nuclear reactors put into<br />

operation as well as the current new<br />

build projects, the demand <strong>for</strong> risk<br />

reduction should be evident. The time<br />

since the last reactor being put into<br />

operation in the west indicates that<br />

we will have a problem when we<br />

intend to rely on experience.<br />

Looking into innovative reactor<br />

development, the last building projects<br />

fall into the 1980ies, followed by<br />

very mixed levels of success on operation.<br />

The German THTR project to<br />

build an industrial demonstrator <strong>for</strong><br />

high temperature reactor technology<br />

lasted from 1971 to 1985 with the<br />

permanent shutdown in 1988. The<br />

French SUPERPHENIX construction<br />

took from 1976 to 1985 and the<br />

reactor was permanently shutdown<br />

1998 never delivering an Energy<br />

Availability Factor above 33 % and<br />

most of the time below 15 %. The<br />

UK fast reactor project in Dounreay<br />

indicates comparable dates and outcomes,<br />

construction started in 1966,<br />

Country<br />

Western Reactors<br />

under construction<br />

first criticality in 1974 with a load<br />

factor of below 30 % and the shutdown<br />

in 1994 (all data from [3]).<br />

Obviously, if we want to be successful<br />

in delivering innovative reactors,<br />

we need to learn again, and this<br />

should happen in a smart way. The<br />

key will be to receive timely feedback/<br />

quick response on the decisions made<br />

instead of the long lead times which<br />

results typically in high costs when<br />

late adaptions are required, see e. g.<br />

the Olkiluoto or the Vogtle project,<br />

where changes in the later construction<br />

phase have not only led to higher<br />

costs but also to massive time delays<br />

which is maybe even more important.<br />

To support the required learning,<br />

we need an innovative and efficient<br />

approach, start smart and small –<br />

looking back to early reactor developments,<br />

zero/low power reactors have<br />

been used as a test bed <strong>for</strong> the next<br />

steps [5, 6] which seems to be highly<br />

promising. The main challenge will be<br />

to make the best out of the money and<br />

to use the time wisely.<br />

Reactor<br />

type<br />

Construction<br />

start year<br />

USA Watts Bar-1 WH 4LP 1973 1996<br />

USA River Bend GE BWR 1977 1985<br />

France Chooz B N4 1984 1996<br />

France Civaux N4 1988 1997<br />

USA Watts Bar-2 WH 4LP 1973/2007 2016<br />

| Table 1<br />

The last constructed nuclear power plants and their grid connection [3].<br />

Grid<br />

connection<br />

p How is starting small possible<br />

in a highly complex multi-billion<br />

industry?<br />

p How did we do this in the 50ies and<br />

60ies? Can we repeat this? What<br />

do we need to do differently in the<br />

21 st century?<br />

p How important are collaborative<br />

opportunities to support upskilling<br />

and engineering development?<br />

The fundamental problem is, when<br />

building an innovative reactor there is<br />

no experience, no plan, so appropriate<br />

cost management is almost impossible<br />

because we don’t know all the steps,<br />

the required technologies, and the<br />

challenges (unknown unknowns).<br />

Introducing a structured process to<br />

the R&D will be a key requirement and<br />

will help to define a structured<br />

approach to the first of a kind (FOAK)<br />

or the later serial build. Learning on a<br />

small real project and going in steps<br />

will allow us to achieve a more<br />

efficient cost reduction than just<br />

learning from experience which typically<br />

takes place at a very later stage of<br />

the project which leads to delays and<br />

cost over runs. These multiple arguments<br />

speak <strong>for</strong> starting a new, innovative<br />

reactor programme on a small<br />

scale using a zero-power reactor to<br />

reduce the risk of the whole development<br />

program.<br />

Why do we need this program?<br />

The last indigenous reactor in the UK<br />

was constructed 1980 and put into<br />

operation in 1988, while the design<br />

Research and Innovation<br />

A Zero-power Facility as a Multi-fold Opportunity to Support Quick Progress in Innovative Reactor Development ı Bruno Merk, Dzianis Litskevich, Anna Detkina, Greg Cartland-Glover, Seddon Atknison and Mark Bankhead

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


The Dungeness disaster<br />

Construction on the new AGR at Dungeness B started in<br />

January 1966. A later historian of the privatization of the<br />

British electricity industry described it as “the single most<br />

disastrous engineering project undertaken in Britain”<br />

[Henney (1994) p. 131]. Among a certain generation of<br />

people, Dungeness B is still a byword <strong>for</strong> failure of<br />

construction, design and project management on a heroic<br />

scale. The project was beset by delays, strikes and cost<br />

overruns.<br />

Henney, A (1994). A Study of the Privatisation of the Electricity<br />

Supply Industry in England & Wales,<br />

London: Energy Economic Engineering<br />

| Figure 1<br />

Simon Taylor (2016) The Fall and Rise of <strong>Nuclear</strong> <strong>Power</strong> in Britain:<br />

A history [8].<br />

also occurred several decades earlier<br />

and the knowledge was not passed<br />

onto the next generation. This has led<br />

to a significant reduction in the<br />

number of the specialists in the<br />

nuclear sector. Looking deeper, the<br />

last indigenous development of a<br />

reactor has been delivered in the late<br />

1960ies, see Figure 1. This development<br />

was pushed by an ambitious<br />

construction programme aiming to<br />

deliver five twin reactor stations and<br />

was quickly rolled out to support<br />

business since export orders were<br />

eagerly anticipated. Thus, the situation<br />

seems to be a bit like the todays<br />

nuclear renaissance supported by<br />

the BEIS (Department <strong>for</strong> Business,<br />

Energy & Industrial Strategy) nuclear<br />

innovation program (NIP) [7] with<br />

the aim to produce business opportunities<br />

<strong>for</strong> UK plc and to become a top<br />

table nation in nuclear latest in 2050<br />

to support the green recovery.<br />

The lead station of the AGR program<br />

was Dungeness B which could<br />

be seen as industrial demonstrator<br />

and a first of a kind and it was a direct<br />

step into a large station without real<br />

stepwise development. It was ordered<br />

in 1965 with a targeted completion<br />

date of 1970. The project did not<br />

progress as expected, being several<br />

times delayed after problems in many<br />

aspects of the reactor design, a bit<br />

comparable to today’s mega projects,<br />

see Figure 1. Finally, electricity generation<br />

began in 1983, 13 years late,<br />

while full power was reached <strong>for</strong> the<br />

first time in 2004, roughly 38 years<br />

after construction began [8]. Another,<br />

early example how costly and time<br />

consuming it can be to learn on a full<br />

power project. The last, more successful,<br />

reactor of the AGR fleet was connected<br />

to the grid in 1989, thus the<br />

last classical UK thermal reactor project<br />

finished construction more than<br />

30 years ago. The last delivery in the<br />

innovative reactor program was the<br />

prototype fast reactor (PFR) which<br />

was announced in 1966 to be built at<br />

Dounreay. The PFR achieved first<br />

criticality in 1974 and grid connection<br />

1975.<br />

Thus, the design of the reactor<br />

system of the commercial fleet took<br />

place in the early 1960ies and the<br />

design of the innovative reactor<br />

system just shortly after, leading to<br />

the situation that the last experience<br />

of construction, commissioning, and<br />

connection to the grid took place in<br />

the late 1980ies [3]. This is a UK view,<br />

but only the dates will be slightly<br />

different in other western countries,<br />

while the introduction just shows that<br />

the situation is comparable. Maybe<br />

the length of time period will be<br />

slightly smaller, but in all cases, it is<br />

too far back in time to rely on the<br />

experience gained at that time.<br />

The key questions to answer are:<br />

p What should we learn from this<br />

history to avoid repetition of such a<br />

very costly disasters – costly in<br />

regards not only to money, but also<br />

with regards to time?<br />

p How can we re-gain experience<br />

and quick response in the whole<br />

process?<br />

p How can we reduce the risk in the<br />

project as mentioned at the end of<br />

the introduction?<br />

A key point will be to learn and to<br />

re- educate experts <strong>for</strong> the nuclear<br />

renaissance since the historic expertise<br />

is obviously lost. In addition, we<br />

can neither af<strong>for</strong>d massive delays<br />

which are predictable and costly when<br />

problems appear at the very late stage<br />

of a project, e.g. in the middle of<br />

construction, nor do we have time to<br />

waste if nuclear should make a<br />

real contribution to a future net-zero<br />

society. Luckily, the situation still<br />

allows us to deliver on these tasks if<br />

we start now and if we use time and<br />

resources wisely. Moreover, in comparison<br />

with the 1960ies we have<br />

more robust and efficient simulation<br />

tools which should speed up the R&D<br />

activities. Digitalisation will help the<br />

whole process via end to end support<br />

and by adopted working practices<br />

instead of simply sending more in<strong>for</strong>mation<br />

to key stakeholders creating a<br />

decision-making bottleneck. To make<br />

this possible some tools require<br />

targeted validation <strong>for</strong> the innovative<br />

reactor designs to leverage their<br />

full potential and to reduce time of<br />

development and costs significantly.<br />

The learning has to be supported<br />

by creating a structured programme<br />

from feasibility through to construction,<br />

see Figure 2, in combination<br />

with following the recently proposed<br />

4 step process [6] consisting of preliminary<br />

studies, an experimental<br />

phase starting with the zero power<br />

reactor as the key steps towards<br />

feasibility. This will support the smallscale<br />

demonstrator providing in<strong>for</strong>mation<br />

<strong>for</strong> the preliminary design<br />

with the first experience of nuclear<br />

power production in a new kind of<br />

reactor. However, in an innovative<br />

reactor development, FOAK is going<br />

all the way through this cycle in each<br />

step. We need to build a complete<br />

programme at sufficient detail encompassing<br />

all of the R&D and skills<br />

development required to effectively<br />

project manage the delivery of each<br />

step right-to-left (thus backwards)<br />

engaging all of the stakeholders at<br />

each level in the process.<br />

| Figure 2<br />

A structured program <strong>for</strong> the development of a nuclear reactor along the recommendations in a WNA white paper [9].<br />

Research and Innovation<br />

A Zero-power Facility as a Multi-fold Opportunity to Support Quick Progress in Innovative Reactor Development ı Bruno Merk, Dzianis Litskevich, Anna Detkina, Greg Cartland-Glover, Seddon Atknison and Mark Bankhead

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />

All mentioned points demonstrate<br />

that we need a new strategy to speed<br />

up learning by identifying strengths<br />

and weaknesses of the capabilities<br />

and the current capacities available to<br />

be able to deliver the end-to-end<br />

approach developed above. Key will<br />

be to work on the known unknowns<br />

and to identify early the unknown<br />

unknowns – areas where the community<br />

is weak, but where we are not<br />

aware of the weakness or the lack of<br />

knowledge. Testing procedures and<br />

technologies early and on smaller<br />

scale will be of high importance to<br />

avoid costly late failures.<br />

Opportunities of a zero- power<br />

reactor as a first step<br />

Developing and delivering an indigenous<br />

zero-power facility should be the<br />

most promising first step into any<br />

innovative reactor program as a part<br />

of an active risk limitation program<br />

<strong>for</strong> the whole nuclear reactor development.<br />

The zero-power facility has the<br />

potential to be used as a multi-fold<br />

opportunity, since it is more than a<br />

system that can be used <strong>for</strong> the validation<br />

of numerical models and their<br />

inherent approximations. It is a FOAK<br />

and the opportunity to go through the<br />

whole process from design to operation<br />

of an innovative reactor facility<br />

testing the feasibility, but in contrast<br />

to any larger reactor it is delivering a:<br />

p low cost opportunity compared to<br />

a power reactor due to limited size<br />

and significantly reduced system<br />

complexity<br />

p low risk opportunity in time,<br />

finance, and nuclear – it is not<br />

rocket science, GUINEVERE [15]<br />

has finally been successfully<br />

delivered – here the reduced complexity<br />

is key, it reduces the number<br />

of critical tasks and the required<br />

safety systems. However, all key<br />

components <strong>for</strong> the nuclear island<br />

and the fuel production have to be<br />

designed, regulated, and delivered<br />

p less complex project, no heat transfer<br />

and no power conversion<br />

system are needed, no extensive<br />

multi-redundant and diverse safety<br />

systems are required as well as no<br />

expensive mitigation devices like a<br />

containment<br />

p quick response opportunity, since<br />

such a project should not take<br />

more than 3 to 5 years, a quick<br />

turnaround and an accelerated<br />

learning curve will be seen.<br />

Knowledge and capacity gaps will<br />

be identified in short time creating<br />

less costly opportunities to close<br />

gaps and even change/adapt the<br />

final pro duct in a comparably late<br />

project phase.<br />

p High flexibility of the facility itself<br />

which could be equipped with<br />

a new core (as done in the<br />

GUINEVERE project) if another<br />

technology should be investigated<br />

A zero-power facility <strong>for</strong> a new technology<br />

is a comparably small project,<br />

which still requires the whole production<br />

chain <strong>for</strong> a nuclear reactor, while<br />

it requests collaboration in an interdisciplinary<br />

team. Thus, it will be a<br />

perfect test case <strong>for</strong> the readiness <strong>for</strong><br />

future, larger projects, assuring an<br />

accelerated learning curve in an innovative<br />

reactor technology on:<br />

p designing,<br />

p licensing,<br />

p constructing,<br />

p commissioning, and<br />

p operation<br />

Where can these advantages<br />

be delivered?<br />

As previously mentioned, the zeropower<br />

facility is a low cost, low risk,<br />

quick response project which delivers<br />

opportunities on different levels, see<br />

Figure 3.<br />

The opportunities of the facility are<br />

in detail:<br />

p Manufacturing<br />

Manufacturing an innovative<br />

reactor of a new technology will<br />

help identifying weak points<br />

( unknown unknowns), upskilling<br />

demands, and already available<br />

pockets of expertise. It will allow<br />

developing and testing of new technological<br />

approaches and advanced<br />

manufacturing techno logies on a<br />

small scale and support the creation<br />

of a core team of experts with<br />

real hands on experience <strong>for</strong> the<br />

following small scale demonstrator<br />

which would make the UK an<br />

| Figure 3<br />

The multiple opportunities which can be delivered in a zero-power facility.<br />

attractive location to deploy these<br />

designs. Testing of new components,<br />

e. g. establishing a pre-industrial<br />

fuel production. It will help<br />

creating and educating the required<br />

supply chain <strong>for</strong> the technologies.<br />

All points will be essential <strong>for</strong> progressing<br />

into the next step of the<br />

development process – the smallscale<br />

demonstrator.<br />

p Experiment<br />

On the one hand, the experiment<br />

will help in the education and<br />

the qualification of future reactor<br />

physics experts, which are highly<br />

demanded worldwide. On the other<br />

hand, it will help to improve the<br />

recognition of reactor physics and<br />

new reactor technologies. Thus, it<br />

will attract bright students of future<br />

generations into nuclear. The<br />

investment in an experiment will<br />

showcase the innovation potential<br />

in nuclear technologies and the<br />

drive to innovate to the public.<br />

p Leading Science <br />

Taking the lead through an investment<br />

into advanced reactor technologies<br />

such as the proposed<br />

molten salt reactor technology.<br />

The investment into the zeropower<br />

facility will create a sustainable<br />

long term claim in an innovative<br />

reactor technology. The facility<br />

will create the opportunity to provide<br />

safety demonstrations and<br />

code validation and deliver an<br />

accelerated learning curve <strong>for</strong> the<br />

operating entity as well as the local<br />

academic community. The demonstration<br />

opportunity will help<br />

creating new IP <strong>for</strong> the country.<br />

The facility will attract top scientists<br />

to the country either in collaborations<br />

or through relocation<br />

while giving UK plc an advantageous<br />

position.<br />


Research and Innovation<br />

A Zero-power Facility as a Multi-fold Opportunity to Support Quick Progress in Innovative Reactor Development ı Bruno Merk, Dzianis Litskevich, Anna Detkina, Greg Cartland-Glover, Seddon Atknison and Mark Bankhead

<strong>atw</strong> Vol. 66 (2021) | Issue 3 ı May<br />


An already successful example:<br />

p Business Opportunity <br />

Finally, besides the leading science,<br />

the facility will allow experiments<br />

<strong>for</strong> international partners and <strong>for</strong><br />

industrial developers who cannot<br />

af<strong>for</strong>d to build their own zeropower<br />

system, as has been<br />

delivered <strong>for</strong> decades through<br />

the BFS at IPPE Obninsk <strong>for</strong> international<br />

sodium fast reactor<br />

development or through the new<br />

opportunities of GUINEVERE at<br />

SCK∙CEN at Mol <strong>for</strong> lead cooled<br />

fast reactor technologies. The<br />

facility will serve industry to<br />

support the home-grown supply<br />

chain and link them to reactor<br />

developers while earning money<br />

through paid experiments.<br />

How can these advantages be<br />

delivered?<br />

The key <strong>for</strong> the success will be to make<br />

the most out of the money invested, as<br />

well as to use the time available<br />

wisely. The zero-power reactor project<br />

has to deliver much more than only<br />

results <strong>for</strong> code validation or safety<br />

demonstration, which would be the<br />

outcome of doing paid experiments at<br />

another facility. Possible opportunities<br />

are given above.<br />

A zero-power reactor project can<br />

build on these first approaches<br />

delivered in project FAITH (see text<br />

box), but it can and has to go much<br />

further. The accelerated learning curve<br />

starts already with the design and<br />

manufacturing of a facility to study<br />

innovative reactor development and<br />

operation, not with the experiment.<br />

Creating, enabling, and edu cating the<br />

supply chain on a very small scale and<br />

reduced complexity system, as a basis<br />

<strong>for</strong> the next level of the small-scale<br />

A first demonstrator of this approach is Project FAITH (Fuel<br />

Assembly Incorporating Thermal Hydraulics) a multi- purpose<br />

project using new, highly innovative approaches to make<br />

better use out of the invested money. Main side purposes are:<br />

Educating new partners from outside of the nuclear industry<br />

how to deliver on nuclear standards while using already<br />

established innovations from other technologies, e. g. modular<br />

manufacturing established in ship building or application of<br />

tailored materials through additive manufacturing. “In FAITH<br />

we intend to demonstrate modular manufacturing on small<br />

scale with low cost and complexity to quickly evaluate a key<br />

technology <strong>for</strong> small modular reactors, while creating an<br />

opportunity <strong>for</strong> qualification and education of the strongly<br />

demanded work<strong>for</strong>ce. This is delivered by a stepwise approach<br />

from easy to build and operate experiments into future<br />

cutting- edge science and technology with a complex and<br />

challenging fluid. All surrounded by digital design and<br />

development technologies from cradle to grave as well as the<br />

approach to deliver a project management integrated with the<br />

technical delivery. This will allow to include product quality<br />

management into the digital twin as well as thinking in terms<br />

of the whole project lifecycle using a common modelling<br />

environment.” [9]<br />

power demonstrator. Key points will be<br />

to develop and test new approaches<br />

(modular manufacturing, advanced<br />

fuel production, and applying digital<br />

twin technology across the whole lifecycle<br />

of the asset), accept failure and<br />

be prepared <strong>for</strong> a quick <strong>for</strong> recovery to<br />

support rapid developments, but in<br />

all cases by using small steps. This<br />

approach reduces risk and promotes<br />

learning and solving problems at each<br />

step. Learning has to be seen as a process<br />

making progress based on UK<br />

capabilities and capacities instead of<br />

just buying a product. It is about<br />

involving all main suppliers into the<br />

development instead of having just<br />

suppliers delivering their parts. This<br />

also implies using the available nuclear<br />

chemistry expertise of academic partners<br />

to improve the available database<br />

<strong>for</strong> the pre- experiments required <strong>for</strong><br />

the design, as well as upgrading of<br />

existing facilities to be able to deliver<br />

on the new challenges, e.g. salt based<br />

uranium fuels production. A further<br />

opportunity is refurbishing existing<br />

facilities and retaining the highly<br />

skilled employees at these facilities<br />

thus serving as a social-economic development<br />

to support a new facility as<br />

in the case of the VENUS facility at<br />

SCK. This will be complemented by<br />

linking with leading groups from outside<br />

nuclear energy to involve them in<br />

the project and attract available expertise<br />

from other areas, e. g. detector<br />

development <strong>for</strong> particle physics delive<br />

ring UK’s contribution to CERN experiments<br />

or modular manufacturing.<br />

It is about using the experiment<br />

to deliver a hands on education to give<br />

the future experts a tier-one experience<br />

in building a new type of reactor as well<br />

as to operate the facility instead of<br />

completely relying on modelling & simulation<br />

as it has often become tradition<br />

in reactor physics. The facility will offer<br />

very effective accelerated learning to<br />

the next generation of engineers and<br />

scientists that comes with de signing,<br />

developing and constructing the facility<br />

as well as running and ana lyzing the<br />

experiments. The facility will be at the<br />

centre of a user community and<br />

attracting international experts while<br />

growing an experimental program <strong>for</strong><br />

a new type of zero- power experiment<br />

in collaboration with national and<br />

international partners. In addition, the<br />

facility will allow the testing of new<br />

detector technologies in a challenging<br />

environment and potentially invest<br />

into developing some tailored, innovative<br />

detector technology.<br />

The development of zero-power<br />

experiments will proceed from easy<br />

to complex to support the learning<br />

process, a further example of learning<br />

from project FAITH. Most probably, the<br />

experimental campaign will be started<br />

with experiments based on a solid salt<br />

block operating at room temperature<br />

to learn how to apply experimental<br />