atw - International Journal for Nuclear Power | 05.2021

Description 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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ISSN · 1431-5254

32.50 €

Is Wind

the Next Nuclear?

Operating Experience from

Ageing Events Occurred

at Nuclear Power Plants

Kazatomprom and

the Nuclear Fuel Cycle


Important notice for international subscribers!

The nuclear phase out in Germany not only concerns the nuclear industry itself but literally

all accompanying national players such as the specialized press.

Therefore, also atwInternational Journal for Nuclear Power must shift its focus and will emphasize

the national context much more than in previous years. One focus will be on the German nuclear

decommissioning market and consistently many articles published will be primarily in German


Despite the fact that much of the journal will be in German, starting January 2022, we plan

to publish some English articles in every issue. Furthermore, the size of the magazine will be

reduced according to the shrinking importance of the national German nuclear market.

As a consequence of all the changes announced above, our international customers have

a special right of immediate and easy termination of subscription which is effective on

January 1 st , 2022.

Nevertheless, to maintain our strong claim to foster nuclear competence a new online platform

atw scientific’ will be introduced in November 2021. Completely in English language, ‘atw scientific’

will be an open-source web platform for worldwide scientific nuclear content, where submissions

will be pre-reviewed and DOIs will be assigned. More information will be available soon!

We would like to take this opportunity to warmly thank you – especially

our gentle international readers – for staying with atw and we hope to

meet you at the new international online platform ‘atw scientific’!

atw Vol. 66 (2021) | Issue 5 ı September

Uranium Supply – Sustainable


Dear Reader, In environmental and economic policy, the term “sustainability” has a high status; it is a popular

springboard for ideas or visions for goals of any kind. The origin of the term “sustainability” can be traced back to the

Brundtland Commission, also called the World Commission on Environment and Development. In 1987, it published the

report “Our Common Future”, in which the concept of sustainable development was formulated and defined for the first

time, thus providing the impetus for a worldwide preoccupation with and public attention to the topic of sustainability.

Following its origins, the term 'sustainable' defines development “that meets the needs of the present without

compromising the ability of future generations to meet their own needs and choose their own lifestyles.”

In this sense, what could be more sustainable than

nuclear energy?

Keyword resource conservation: Nuclear power

plants under construction and commissioning today

will, by design, achieve technical lifetimes of 60 years

and more from the outset. For nuclear power plants in

operation today, lifetimes of 60 years are now a matter

of course, 80 years are partly under review and

100 years are under consideration.

Keyword resource availability: Both in terms of

sustainability and in terms of an investment in a nuclear

power plant that can be operated for up to 100 years,

the question of the availability of nuclear fuel arises, i.e.

with today’s nuclear fuel input, the question of uranium


Since the mid-1960s, the “Red Book” – Uranium:

Resources, Production and Demand* – by the Nuclear

Energy Agency (NEA) of the Organisation for Economic

Development (OECD) and the International Atomic

Energy Agency (IAEA) has provided an answer to this

question, which is periodically discussed here. The Red

Book provides a detailed and reliable insight into the

current situation of the entire uranium and nuclear fuel

supply. In addition, the Red Book provides an outlook

on the demand and supply forecast for the coming

decades. The data in the 28 th edition, which has now

been published, has been compiled with the support of

37 member states of both organisations and analyses by

the experts of NEA and IAEA. In addition, other aspects

of nuclear fuel supply are outlined, such as environmental

protection and price development.

On the uranium supply side, the Red Book identifies

a small but renewed and thus steady increase in

resources compared to 2017: according to the tiered list

classified by cost, a total of 8.070 million tonnes of

uranium at extraction costs < US$ 260/kgU (or < US$

100/lbU) are reported as reserves on the cut-off date of

January 1, 2019. This is 0.1 % more than two years

earlier. In the previous report, the same increase was

recorded. The main cause is seen in the changed market

situation with lower revenues on the uranium extraction

side, which is reflected in lower efforts in the search

and exploration of new uranium deposits. Natural

uranium is available in sufficient quantities for nuclear

power plant needs, in the short and medium term as

well as in the long term, which has created significant

price pressure that has caused the uranium price to fall

from its last high in 2007 of around US$ 130/lb U 3 O 8 to

the current level of around US$ 30/lb U 3 O 8 ; in the

meantime, in 2016, a low of just under US$ 20/lb was

recorded. This is associated with lower global uranium

exploration activities and consequently lower reserve

growth – although more new uranium sources were

found than uranium mined for energy production in

the same period. The current Red Book shows that

China, India, Canada, Kazakhstan and the USA were

leading in the uranium extraction sector, i.e. exploration

and establishment of mines, in the period from 2016 to

2018. The investments made in Canada alone were

higher than those of the next five countries in total.

Expenditures totalled approximately US$ 1.8 billion.

Global uranium production in 2019 was 54,244 tU,

about 1 % higher than in the previous year 2018 but

about 16 % lower than in 2016. 92 % of the uranium

demand of about 59,200 t in 2019 was thus covered by

current production and 8 % by so-called secondary

sources, i.e. the return of uranium from reprocessing or

former military material and stockpile withdrawals.

With regard to medium-term security of supply and

the extent of future uranium production, the authors of

the Red Book point to a balanced constellation until

2040. The existing uranium mines, those currently

being developed and those planned, will foreseeably

cover the uranium demand even in the scenario of

a high increase in nuclear energy from currently

396,000 MW worldwide to 626,000 MW in 2040.

Today’s reserves of 8,070 million tonnes of uranium

are sufficient to cover the current nuclear fuel demand

for 135 years. In addition, resources are shown to be in

the order of another 15 million tonnes of uranium. On

the nuclear fuel supply side, there is thus neither a

supply shortage nor an acute need for action.

In addition, the innovation potential of nuclear

technology offers further perspectives; on the uranium

extraction side, for example, the tapping of the uranium

reservoir in the world’s oceans, which is quasi-infinite

according to current estimates, up to advanced fuel

cycles or new nuclear fuels such as thorium, which

would expand today’s resources by a factor of 100 and


Uranium supply is therefore a sustainable factor of

nuclear energy, which also offers future generations

sufficient potential for utilisation and even the urgently

needed expansion of power generation capacities.

Christopher Weßelmann

– Editor in Chief –

*) Uranium 2020:

Resources, Production

and Demand, A Joint

Report by the OECD

Nuclear Energy

Agency and the

International Atomic

Energy Agency, NEA

No. 7551, Paris, 2020



Uranium Supply – Sustainable

atw Vol. 66 (2021) | Issue 5 ı September



Issue 5





Uranium Supply – Sustainable. . . . . . . . . . . . . . . . . . . . . . . . 3

Inside Nuclear with NucNet

Why Moscow Is Banking on Small Reactors to Power Economic

Development in Remote Regions . . . . . . . . . . . . . . . . . . . . . .6

Mattia Baldoni

Did you know? 7


Verifying the diameter of uranium fuel pellets

produced at the Ulba Metallurgical Plant

(Courtesy of NAC Kazatomprom JSC).

Calendar 8

Feature | Research and Innovation

Is Wind the Next Nuclear? . . . . . . . . . . . . . . . . . . . . . . . . . . .9

Schalk Cloete

Interview with Yves Desbazeille

“Since the Beginning, FORATOM Has Advocated for the

Taxonomy to Follow a Technology Neutral Approach.” . . . . . . . 14

Operation and New Build

Operating Experience from Ageing Events Occurred

at Nuclear Power Plants . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Antonio Ballesteros Avila and Miguel Peinador Veira

At a Glance

Ultra Safe Nuclear Corporation . . . . . . . . . . . . . . . . . . . . . . . 24


Westinghouse Fuel Design Advancements . . . . . . . . . . . . . . . 26

Derek Wenzel, Uffe Bergmann and Juan Casal

Kazatomprom and the Nuclear Fuel Cycle . . . . . . . . . . . . . . . . 30

Mazhit Sharipov

Site Spotlight

Nuclear Expertise for Germany – Indispensable

Even After the German Nuclear Phase-out . . . . . . . . . . . . . . . 34

Nuclear Competencies in Germany – a Legitimate Case

Also After the Nuclear Phase-out . . . . . . . . . . . . . . . . . . . . . 38

Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations

During Static and Dynamic Impact . . . . . . . . . . . . . . . . . . . . 42

Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

Research and Innovation

Improving Henry-Fauske Critical Flow Model

in SPACE Code and Analysis of LOFT L9-3. . . . . . . . . . . . . . . . 50

BumSoo Youn

Non-destructive Radioactive Tracer Technique

in Evaluation of Photo- degraded Polystyrene Based

Nuclear Grade Ion Exchange Material . . . . . . . . . . . . . . . . . . 54

Pravin U. Singare

News 62

Nuclear Today

As Science Turns Up the Heat on Climate Change Sceptics,

How Long Before the Nero-like Nuclear Deniers

Must Change Their Tune? . . . . . . . . . . . . . . . . . . . . . . . . . . 66

Imprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48


atw Vol. 66 (2021) | Issue 5 ı September



Research and Innovation


9 Is Wind the Next Nuclear?

Schalk Cloete

Interview with Yves Desbazeille

14 “Since the Beginning, FORATOM has Advocated

for the Taxonomy to Follow a Technology Neutral Approach.”

Operation and New Build

18 Operating Experience from Ageing Events Occurred

at Nuclear Power Plants

Antonio Ballesteros Avila and Miguel Peinador Veira


26 Westinghouse Fuel Design Advancements

Derek Wenzel, Uffe Bergmann and Juan Casal

30 Kazatomprom and the Nuclear Fuel Cycle

Mazhit Sharipov

Site Spotlight

34 Nuclear Expertise for Germany – Indispensable Even After


the German Nuclear Phase-out

Nuclear Competencies in Germany – a Legitimate Case Also After

the Nuclear Phase-out


atw Vol. 66 (2021) | Issue 5 ı September


Why Moscow is Banking on Small Reactors

to Power Economic Development in Remote Regions

Mattia Baldoni


Russia says it faces inevitable challenges with plans to build its first land-based small modular

reactor because of poor transport infrastructure in the eastern public of Yakutia, but is confident

the project will go ahead and that the country has a big enough domestic market for serial SMR

production – which could begin as soon as 2030.

State nuclear corporation Rosatom confirmed reports late

last year that Russia is planning to build a land-based SMR

in Yakutia, also known as Sakha, an autonomous republic

4,000 km to the east of Moscow, between Siberia and

Russia’s far east. Rosatom said it is aiming to commission

the unit by 2028.

Foremost among hurdles are the remote location and

poor transport infrastructure because of permafrost.

Rosatom, however, remains confident that construction

will go ahead as scheduled and says progress is being made.

A field survey has been completed at a potential site in

Ust-Kuyga, a settlement on the Yana River with a population

of less than 1,000. Rusatom Overseas, Rosatom’s foreign

business division, is planning to draw up a declaration of

intent for Yakutia to invest in the project.

Rosatom said it could not give cost estimates because the

final price will depend on factors such as location, safety

requirements and local regulatory standards. “The exact

cost for each specific customer may be determined by the

results of a detailed feasibility study, taking into account

particular specifications of the project,” the company said.

“What we can say is that final electricity prices will be

competitive compared to other sources of energy in those

locations after factoring in carbon fuel prices and infrastructure

costs, and even in comparison with other SMR


Rosatom believes it has a large enough domestic market

for serial SMR production. Serial production, together with

the development of government-private partnerships, is

crucial if SMRs are going to be economically viable. The

Nuclear Energy Agency said recently that SMRs could become

commercially viable by the early 2030s, but efforts to build

the first plants would benefit from international collaboration

and more government support.

If SMRs are manufactured in a mass production fashion,

similar to commercial aircraft, the economic benefits could

be significant, the NEA said. But this would require that

the market for a single design be relatively large and raises

the possibility that only a small number of the many

designs under development will ultimately succeed.

In the UK, a consortium led by Rolls-Royce said an SMR

it is developing will initially cost about £2.2bn per unit,

dropping to £1.8bn by the time five have been completed.

This means it will be comparable with offshore wind at

around £50/MWh.

Russia’s energy strategy to 2035 (Russian only) stresses

the role nuclear can play in energy security and the drive

for zero emissions. It says there is a need for low-power

nuclear plants for remote regions, but says nuclear’s

economic competitiveness needs to increase.

One of Moscow’s major considerations as it seeks to

modernise its energy infrastructure and provide affordable

electricity is how to provide power for remote areas like the

Arctic. SMRs represent a promising source of energy for

areas away from central power grids. “With the help of

SMRs, the Arctic can achieve net-zero emissions as early as

2040,” said Anton Moskvin, vice-president for marketing

and business development at Rusatom Overseas.

The NEA said the most optimistic deployment scenarios

assume successful licensing and the establishment of the

factory production and associated supply chain that would

lead to cost competitiveness. In a more conservative

low-deployment scenario, SMRs would be considered

expensive to build and operate, and thus only a limited

number of projects would be completed.

Traditional energy sources such as coal and gas are

falling out of favour as countries join the fight against

climate change. They are also unable to satisfy growing

demand for heat and electricity in remote area areas. Coal

and oil, for example, need to be moved to the site along

with all their ancillary services. The simplicity of SMRs

means they could be taken to a rural location by road or

sea and operate with minimal intervention for 60 years or

more. Rosatom wants the Yakutia SMR to be a clean source

of heat and electricity both for mining facilities and for

local residents, replacing carbon-intensive coal-fired and

diesel facilities. It says the plant will contribute to the

reduction of up to 10,000 tonnes of CO 2 per year.

The proposed Yakutia SMR is based on Russia’s

RITM-200, an advanced pressurised water reactor unit

which is already operational on new-generation icebreakers.

Russia has also led the way in the SMR sector with its

first-of-a-kind floating nuclear power plant Akademik

Lomonosov, which has two KLT-40S reactors and is the

world’s first advanced SMR. It was connected to the grid in

December 2019 in Pevek, Chukotka Peninsula. In May

2020 it began full commercial operation, generating

electricity for households and local industries in Russia’s

east Arctic region.

According to the NEA, Rosatom is planning more

floating SMRs at the Baltic Shipyard in St. Petersburg. In

parallel, it has been developing the RITM-200 for both

floating and land-based deployment. Serial construction

could start by 2030, with the first units to be installed at

Russia’s biggest mine sites.

Possible candidate sites for SMRs are the Suroyam iron

ore deposit near Chelyabinsk in southwest Russia, the

Baim minerals deposit in Chukotka, in Russia’s far east,

and other sites in Yakutia. Reports earlier this month in

Russia said president Vladimir Putin has approved a

Rosatom proposal to power the Baim mining venture by

building as many as five floating nuclear power plants.

Rosatom also says interest in Russian-designed floating

nuclear power plants is growing in Latin America, Asia,

and Africa – all areas where electricity is needed in remote

locations and a problem for which Russia thinks it is

getting close to a solution.

The race to develop and manufacture SMRs is intense,

with at least 72 reactor concepts under various stages of

development in countries as diverse as Argentina, Canada,

the US, the UK, China, Japan, South Korea and France. The

question of the market remains central, says the NEA, but

Inside Nuclear with NucNet

Why Moscow is Banking on Small Reactors to Power Economic Development in Remote Regions

atw Vol. 66 (2021) | Issue 5 ı September

with its state-backed corporations and access to federal

funding, this is one area where Russia might have an

advantage over rivals in countries where governments are

reluctant to intervene in the market.

“It is a ‘chicken and egg’ situation,” said Frederik Reitsma,

team leader for SMR technology at the International Atomic

Energy Agency. “On the one hand, investment to develop

and deploy SMRs requires a secured market and demand for

the product, but on the other, one cannot secure the market

without funding to develop and demonstrate, or even to do

the necessary research or build test facilities that may be

required for licensing. Potential investors are hesitant to

invest in new technology if they are unsure about the market



Mattia Baldoni

NucNet – The Independent Global Nuclear News Agency




Did you know?

Electricity Price Hike in Summer 2021

The Institute of Energy Economics at the University of Cologne

(EWI) published an analysis of the electricity price hike observable

in the first half of 2021 on the German wholesale market for

electricity under the German title “Anstieg der Strompreise

im Sommer 2021”. Similar developments take place in other

European markets too. The analysis uses the EWI-Merit-Order-

Tool and concludes that the major drivers of increasing electricity

prices are high fuel prices and a high price for CO 2 -allowances in

the EU Emission Trade System (ETS). Gas prices reached their

highest level for over 10 years in the first week of July 2021 with

36 Euro/MWh and coal reached its highest price level since 2011

with 15 Euro/MWh. At the same time the price for an ETS

certificate for the emission of one tonne of CO 2 rose from 33 Euro/

tonne in January 2021 to over 57 Euro at the end of June receding

a little thereafter.

This input price development caused a significant effect on the

marginal cost of gas and coal power plants which increased

significantly not only compared to covid-crippled 2020 but also

compared to 2019. In combination with higher demand in 2021

compared to 2020 (the electricity demand increased by 5 per cent

in the first half of 2021 compared to 2020) and a shortened merit

order as consequence of power plants closing down in the the

first steps of the German coal phase-out, a market environment

was created that exerted intensive upward pressure on wholesale

electricity prices. While a reduced production of renewable

power, particularly wind, also contributed to market pressure, the

analysis indicates that the so called residual demand remained

within the bounds of what has been observed during the past

years and was not a significant factor for rising prices.

Looking beyond the analysis on Germany one finds a high

electricity price level in the UK too. In January 2021 the monthly

average price for day ahead baseload contracts rose above

90 Pound/MWh, within striking distance of the severly critized

strike price of 92.50 Pound/MWh for the Hinkley Point C (HPC)

nuclear power plant under construction and even higher than the

initial strike prices for Hinkley Point C and Sizewell C (SZC) in case

the Sizewell project is realised which are 89.50 Pound/MWh for

HPC and 86.50 Pound/MWh for SZC. It has to be said though, that

the inflation adjusted current strike prices are higher than the

initial ones.

Prices for Electricity and Gas

in Euro/MWh for CO 2 in Euro/tonne

Wholesale Electricity

Price 2019

Wholesale Electricity

Price 2020

Wholesale Electricity

Price 1 st half of July 2021

Wholesale Gas

Price July 2021

CO 2 -Price

(per tonne)






Anstieg der Strompreise

im Sommer – Wie

Brennstoff- und

Zertifikatepreise sowie

die Residualnachfrage

auf Großhandelsstrompreise

wirken. Eine

Analyse mit dem EWI

Merit-Order-Tool; Çam,

Arnold, Gruber; Energiewirtschaftliches


an der Universität zu

Köln (EWI); Juli 2021


| Wholesale Electricity Prices Germany August 2020 to July 2021; www.smard.de.

For further details

please contact:

Nicolas Wendler


Robert-Koch-Platz 4

10115 Berlin


E-mail: presse@



Did you know?

atw Vol. 66 (2021) | Issue 5 ı September





04.10. – 05.10.2021

AtomExpo 2021. Sochi, Russia, Rosatom,


Online Conference 04.10. – 06.10.2021

ICEM 2021 – International Conference on

Environmental Remediation and Radioactive

Waste Management. ANS,


12.10. – 13.10.2021

TotalDECOM 2021. TotalDECOM, Manchester,

UK, www.totaldecom.com

13.10. – 14.10.2021

NuFor 2021: Nuclear Forensics Conference.

IOP Institute of Physics, London, UK,


Hybrid Conference 16.10. – 20.10.2021

ICAPP 2021 – International Conference on

Advances in Nuclear Power Plants. Khalifa

University, Abu Dhabi, United Arab Emirates,


19.10. – 21.10.2021

ICOND 2021 – 10 th International Conference

on Nuclear Decommissioning. AiNT, Aachen,

Germany, www.icond.de

Postponed to 24.10. – 28.10.2021

TopFuel 2021. Santander, Spain, ENS,


15.11. – 17.11.2021

NESTet2021 – Nuclear Education and Training.

ENS, Brussels, Belgium, www.ens.eventsair.com

Postponed to 30.11. – 02.12.2021

Enlit (former European Utility Week

and POWERGEN Europe). Milano, Italy,


30.11. – 02.12.2021

WNE2021 – World Nuclear Exhibition.

Paris, France, Gifen,



26.01. – 28.01.2022

PowerGen International. Clarion Events, Dallas,

TX, USA, www.powergen.com

06.03. – 11.03.2022

NURETH19 – 19 th International Topical Meeting

on Nuclear Reactor Thermal Hydraulics.

SCK·CEN, Brussels, Belgium,


05.04. – 07.04.2022

GLOBAL 2022 – International Conference

on Nuclear Fuel Cycle. Sfen, Reims, France,


Postponed to Spring 2022

4 th CORDEL Regional Workshop –

Harmonization to support the operation

and new build of NPPs including SMR.

Lyon, France, World Nuclear Association,


04.05. – 06.05.2022

NUWCEM 2022 – 4 th International Symposium

on Cement-Based Materials for Nuclear

Wastes. Sfen, Avignon, France,


15.05. – 20.05.2022

PHYSOR 2022 – International Conference

on Physics of Reactors 2022. ANS, Pittsburgh,

PA, USA, www.ans.org

22.05. – 25.05.2022

NURER 2022 – 7 th International Conference

on Nuclear and Renewable Energy Resources.

ANS, Ankara, Turkey, www.ans.org

Postponed to 30.05. – 03.06.2022

20 th WCNDT – World Conference

on Non-Destructive Testing. Incheon, Korea,

The Korean Society of Nondestructive Testing,


26.10. – 28.10.2021

VGB Conference Chemistry. Ulm, Germany,

VGB PowerTech, www.vgb.org

31.10. – 12.11.2021

COP26 – UN Climate Change Conference.

Glascow, Scotland, www.ukcop26.org

Postponed to 07.11. – 12.11.2021

PSA 2021 – International Topical Meeting on

Probabilistic Safety Assessment and Analysis.

ANS, Columbus, OH, USA,


29.03. – 30.03.2022


Leipzig, Germany, KernD and KTG,


04.04. – 08.04.2022

International Conference on Geological

Repositories. Helsinki, Finland, EURAD,


10.07. – 15.07.2022

SMiRT 26 – 26 th International Conference on

Structural Mechanics in Reactor Technology.

German Society for Non-Destructive Testing,

Berlin/Potsdam, Germany, www.smirt26.com

04.09. – 09.09.2022

NUTHOS-13 – 13 th International Topical Meeting

on Nuclear Reactor Thermal Hydraulics,

Operation and Safety. ANS, Taichung, Taiwan,


This is not a full list and may be subject to change.


atw Vol. 66 (2021) | Issue 5 ı September

Is Wind the Next Nuclear?

What the nuclear stagnation tells us about the challenges

that lie ahead for renewable energy

Schalk Cloete

Introduction Levelized costs of electricity often dominate the energy and climate debate. Green advocates like to

believe that if we only invest enough in wind and solar, the resulting cost reductions will soon put an end to fossil fuels.

While this is already a strongly oversimplified viewpoint, a narrow focus on cost makes such simplistic analyses even

less helpful.

This article will elaborate by example of two clean energy

technologies that face very different non-economic

barriers: nuclear and wind.

The Nuclear Stagnation

When technology is new and exciting, people only see the

positives. It is only when we reach market shares where

people start experiencing negative impacts that opinions

turn negative.

In the case of nuclear, the global expansion was

handicapped by the Chernobyl disaster in 1986, and the

nascent developing world expansion was interrupted by

Fukushima in 2011. As shown in Figure 1, Chernobyl

happened when nuclear reached about 5 % of the global

energy supply. Today, we are back down to 4.2 %.

Deaths from Chernobyl are estimated somewhere

between 4,000 and 60,000 1 , only 31 of which can be

attributed directly to the blast and high-level radiation

exposure. Fukushima had a much lower death toll at 574 2 ,

almost all due to evacuation stress. For perspective, it is

estimated that one future premature death results

from every 300 to 3000 tons of burnt carbon 3 or 1100 to

11,000 tons of CO 2 released into the atmosphere. Hence,

if we assume that the 93,000 TWh of nuclear power

generated to date displaced coal at 0.8 ton-CO 2 /MWh, the

74 billion tons of CO 2 avoided by nuclear has already saved

7–70 million lives, not counting the additional impact of

avoided air pollution.

There is much controversy around these estimates, but

they serve to illustrate that the public health benefits of

nuclear easily outweigh the costs. Clearly, the public

backlash against nuclear was not rational from a bigpicture

view. But that does not matter. The effects of public

resistance are real, whether it is rational or not.

A Wind Stagnation?

As Figure 1 shows, wind market share is currently

expanding at about half the speed of nuclear market share

in the seventies and eighties. Although wind does not face

risks from black swan events 4 like nuclear, it faces its own

brand of public resistance, both to the turbines themselves

and the extensive network expansions required to integrate

higher wind shares.

| Fig. 1.

Comparison of the global expansion of wind and nuclear from BP Statistical Review data. Both wind and

nuclear electricity output are multiplied by 2.5 to convert it to displaced primary fossil energy. Source:


As our societies become more advanced, we increasingly

demand an invisible energy system. Over here in Norway,

the usually reserved population is reacting furiously 5 to

onshore wind expansion plans. Turbines dotting the

pristine Norwegian landscape are unimaginable to this

wealthy society, the origin of its wealth 6 notwithstanding.

In Germany, resistance to turbines and grid expansions

has almost brought onshore wind expansion to a halt 7 at

current levels (about 7 % of total energy demand).

That is wind’s greatest challenge: It is the most visible

energy technology we have. As wind power continues to

expand and turbines grow ever larger, its visibility will only

grow while society’s tolerance for highly visible energy

technologies continues to decline. Advanced societies also

become increasingly concerned with nature preservation,

leading to additional hurdles related to bird protection 8 .

Offshore wind can help, but it will need to be built

far from shore to be sufficiently invisible, making it more

costly. It also faces further economic challenges from

wake effects that strongly reduce output 9 as total installed

capacity increases. In addition, offshore wind requires

large grid expansions to serve inland regions. Making



1 https://ourworldindata.org/what-was-the-death-toll-from-chernobyl-and-fukushima

2 https://ourworldindata.org/what-was-the-death-toll-from-chernobyl-and-fukushima

3 https://www.frontiersin.org/articles/10.3389/fpsyg.2019.02323/full

4 https://en.wikipedia.org/wiki/Black_swan_theory

5 https://www.worldoil.com/news/2020/12/9/more-norwegians-saying-not-in-my-backyard-to-onshore-wind-farms

6 https://edition.cnn.com/2021/02/17/world/climate-hypocrites-uk-canada-norway-intl/index.html

7 https://www.dw.com/en/german-wind-energy-stalls-amid-public-resistance-and-regulatory-hurdles/a-50280676

8 https://www.cleanenergywire.org/news/german-environment-ministry-weighing-wind-farm-distance-regulations-protect-birds

9 https://www.agora-energiewende.de/en/publications/making-the-most-of-offshore-wind


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these expansions invisible (underground cables) is very


Solar is not immune either. Large solar farms can

ruin scenic vistas and damage natural habitats. Waste

from decommissioned plants could be another major

concern. 10

Furthermore, transmitting solar energy from

sunny regions to population centers (often poorly

correlated 11 ) will face similar resistance to wind network

expansions. Ultimately, any industrial-scale energy

technology has its drawbacks, and variable renewables

are no exception 12 .

Like nuclear, most of the resistance to renewables is not

rational from a big-picture viewpoint. Surely, seeing the

occasional wind turbine in the wild is worth the climate

benefits. But again, the rationality of this resistance does

not matter. What matters is the effect it has on clean

technology deployment.

The Undervalued Issue of System Complexity

Megaprojects that involve many interconnected technical,

economic, political, and social challenges are extremely

difficult to execute on time and within budget. Nuclear

offers a prime example with many stories of budgets

and timelines that were grossly exceeded, increasingly

stringent safety regulations being only one reason 13 .

In comparison, the modular construction and

installation of a wind turbine is child’s play. For decades,

the simple and standardized construction and installation

of wind and solar have been a big driver behind their

impressive growth and falling costs.

But this will not last. Higher wind market shares require

vast grid expansions (often into neighboring countries)

and lots of integration with other sectors that previously

operated independently (and need to be reinvented to run

on clean energy). In the longer term, this includes a large

hydrogen production, transport, storage, and end-use

sector that must be built from scratch. Executing this

enormous integrated project in a shifting policy- technology

landscape with impossibly tight climate timelines and

increasing public resistance can easily surpass the scale

and complexity of nuclear projects.

As the nuclear example shows, sub-optimal execution

should be expected in such a large, complex, and multifaceted

project, inflating overall system costs and slowing

the energy transition.

The remainder of this article will quantify these effects

using a modified version of a published energy systems

model 14 loosely based on Germany (further model details

are given in the Appendix).

Model Results

The coupled electricity-hydrogen system model is run for

three distinct scenarios, each varying the most relevant

model parameter:

p No CCS or Nuclear: In this renewables-dominated

scenario, the critical variable is the added costs from

integration challenges, public resistance, and high

system complexity. These costs are varied via cases that

double and triple the added electricity and hydrogen

grid costs needed to connect wind and solar generators

to demand centers.

p No CCS: This scenario allows nuclear but not CO 2

capture and storage (CCS). The critical variable in this

scenario is the cost of constructing nuclear power

plants, varied between 4000 and 8000 €/kW.

p All Technologies: CCS is allowed to decarbonize

natural gas-fired power and hydrogen production. The

natural gas export price is the critical variable in this

| Fig. 2.

Optimal electricity generation and consumption in the different cases. CCS = Natural gas power production with CO 2 capture and storage; Natural gas = Unabated

natural gas power production; Others = Efficiency losses from batteries and electricity consumption involved in hydrogen storage.

10 https://hbr.org/2021/06/the-dark-side-of-solar-power

11 https://energycentral.com/c/ec/what-potential-distributed-generation

12 https://www.brookings.edu/wp-content/uploads/2020/01/FP_20200113_renewables_land_use_local_opposition_gross.pdf

13 https://arstechnica.com/science/2020/11/why-are-nuclear-plants-so-expensive-safetys-only-part-of-the-story/

14 https://www.sciencedirect.com/science/article/pii/S0360319920336673?via%3Dihub


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scenario and is varied between 4 and 8 €/GJ (natural

gas transmission costs are added separately).

In addition, a Mix case is added where a balanced mix of

renewables, nuclear, and natural gas with CCS is deployed.

This case shows the potential of deploying renewables and

nuclear up to the point where public resistance and

complexity become limiting, and deploying a limited

amount of natural gas where it adds the most value, i.e.,

hydrogen production and system balancing.

In each scenario, the model optimizes investment

and hourly dispatch of all the technologies listed in the

Appendix to minimize total system costs. The default

settings of the three critical variables in the scenarios are

1) no increase in grid costs, 2) 6000 €/kW nuclear capital

cost, and 3) 6 €/GJ natural gas export price. A high

CO 2 price of 200 €/ton is assumed in all cases.

The Electricity Mix

Electricity production and consumption from the optimal

technology mixes for different cases are shown in Figure 2.

Starting from the No CCS or Nuclear scenario on the

left, we see that higher transmission costs reduce the

deployment of renewables and increases CO 2 emissions

from unabated natural gas-fired power production. With

the base grid costs (1x) derived from a Berkeley Lab

study 15 , all required hydrogen is made locally using

electrolysis. However, this scenario requires 267 GW of

installed wind capacity (two-thirds onshore) – quadruple

the current installed base in Germany, where public

resistance already has a large negative impact on wind

expansion plans. In addition, 378 GW of solar power is

needed (7x the current level).

When transmission costs are tripled – a likely scenario

given the public resistance and complexity anticipated

from such vast wind and solar deployment – a considerable

amount of unabated natural gas-fired power production

is deployed. Even with a CO 2 price of 200 €/ton, higher

renewable energy integration costs preserve a central role

for unabated natural gas in the power system. In addition,

this case relies on expensive hydrogen imports via green

ammonia for 28 % of the hydrogen demand.

The inclusion of nuclear in the No CCS scenario creates

a near 100 % nuclear system when projects are well

executed to build plants for 4000 €/kW. According to the

latest power plant cost database from the IEA and NEA 16 ,

nuclear plants have investment costs ranging from

2300 €/kW in Korea to 4500 €/kW in the United States, so

such costs are feasible. Even at the baseline cost of

6000 €/kW, nuclear maintains a central role in the power

system. However, at 8000 €/kW (e.g., the Hinkley Point C 17

project), costs become excessive, and the optimal solution

is the same as the base case (1x) in the No CCS or Nuclear


When CCS is allowed in the All Technologies scenario,

natural gas-fired power plants with CCS become the

favored technologies at natural gas export prices of 6 €/GJ

and lower. Renewable energy deployment is low because

CCS (and nuclear) plants are best operated as baseload

generators and natural gas is used for all hydrogen

production, removing the possibility of electrolysis to

balance fluctuating wind and solar output. The natural gas

price of the base case (6 €/GJ + transmission) is a little

| Fig. 3.

Optimized costs of the energy system in the different cases. The cost of generating clean electricity

for green hydrogen production (either from renewables or nuclear) is included directly in green

hydrogen costs.

higher than long-term European natural gas prices

projected in the IEA Stated Policies Scenario in the latest

IEA World Energy Outlook 18

and implies large profit

margins for natural gas producers. The IEA’s Pariscompatible

Sustainable Development Scenario projects

natural gas prices below the 4 €/GJ level due to reduced


When CCS is available, steam methane reforming of

natural gas is used for almost all hydrogen production,

strongly reducing the amount of extra electricity

pro duction needed for electrolysis. Natural gas is only

driven out of the power sector when prices rise to

8 €/GJ, displaced mainly by nuclear. However, it remains

responsible for 94 % of hydrogen production, even at this

high price level.

Finally, the Mix case shows the result when wind and

solar power are forced to levels likely to prevent excessive

public resistance and system complexity: 80 GW of onshore

wind, 40 GW of offshore wind, and 160 GW of solar.

This case also assumes an efficient nuclear rollout at

4000 €/kW and low natural gas prices of 4 €/GJ due to

reduced demand. One-third of hydrogen comes from

electrolysis in this case, which plays a central role in

balancing renewables while nuclear provides baseload

power (see Figure 4 in the Appendix).

Total System Costs

The minimized annual system costs of the different

cases are shown in Figure 3. For the No CCS or Nuclear

scenario, the high costs of unabated natural gas-fired

power production (mainly from the high CO 2 price) are

clearly visible. However, this costly generation remains the

cheapest way to supply power during extended periods of

low wind and solar output. In addition, significant

transmission, storage, and ramping costs are shown.

When transmission costs are tripled (the 3x case), the

model chooses to deploy considerably fewer renewables

to reduce this high integration cost, resulting in much

higher costs from unabated natural gas power plants and

hydrogen imports.


15 https://www.sciencedirect.com/science/article/abs/pii/S0301421519305816?via%3Dihub

16 https://www.oecd-ilibrary.org/energy/projected-costs-of-generating-electricity_20798393

17 https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_station

18 https://www.oecd-ilibrary.org/energy/world-energy-outlook-2020_557a761b-en


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When nuclear plants can be built for 4000 €/kW in

the No CCS scenario, energy system costs reduce

substantially. This case requires no natural gas power

production and almost no added transmission, storage,

and ramping costs. Nuclear plants operate at baseload

conditions with electrolyzers used to balance daily

demand variations, leading to an attractively simple

energy system. Increasing the cost of nuclear to

6000 €/kW brings more wind and solar into the system

with the associated balancing costs. If nuclear costs

escalate to 8000 €/kW, nuclear is too expensive, and the

system reverts to the 1x case in the No CCS or Nuclear

scenario (as shown in Figure 2).

The addition of CCS in the All Technologies scenario

brings further cost reductions, especially with a natural

gas export price of 4 €/GJ. The main benefit of including

CCS is that hydrogen becomes much cheaper. However, a

system that is so dependent on natural gas is undesirable,

and substantially higher shares of renewables and nuclear

would be preferred from the perspective of energy security

and long-term sustainability. Natural gas export prices

need to rise to unrealistic values of 8 €/GJ before nuclear

(at 6000 €/kW) displaces natural gas power plants with


Finally, the Mix case illustrates how these three

technology classes (renewables, nuclear, and CCS) can be

combined to create a cost-effective system that avoids the

challenges from over-reliance on any single technology

class. Renewables and nuclear are deployed to levels

where complexity and public resistance are deemed

manageable, allowing for optimistic assumptions (no grid

cost escalations and 4000 €/kW nuclear), while natural

gas demand is minimized, making a low export price of

4 €/GJ seem reasonable. As shown in Figure 3, this case

with 401 TWh/year of natural gas demand is only 10 %

more expensive than the cheapest case that demands an

unrealistic 1743 TWh/year of natural gas.


An over-reliance on any energy technology class can be

detrimental, creating a range of social, political, and

environmental challenges. As discussed in this article, the

hurdles facing wind and nuclear are very different, but

both are highly significant. As wind power continues to

expand to the level where nuclear peaked (it is currently

about one-third of the way there), public resistance and

system complexity will continue to mount, causing

substantial headwinds.

Ultimately, wind and solar will follow the same S-curve

deployment pattern 19 of all other energy technologies, but

the plateau may well come earlier than proponents

believe. For this reason, nuclear and CCS should be

encouraged for parallel deployment, especially in regions

with poorer wind/solar resources or high population

densities. The ability to construct these energy-dense

technologies close to demand and dispatch them as

needed results in a much simpler and less obtrusive

energy system.

An all-of-the-above approach to the energy transition

guided by technology-neutral policies remains the

rational choice. Each technology class has its limits and

weaknesses, and we need a balanced mix to allow each

technology to do what it does best. Cheap wind and solar

are great at moderate deployment levels, but other clean

technologies will be needed to reach net-zero. Nuclear is

one of these options, while CCS has a vital role to play in

system balancing and clean fuel provision.

The global energy transition is a clean energy team

effort. All the players deserve our support.

Appendix: Model Description

A modified version of the energy system model discussed

in a previous article 20 is used in this study to illustrate the

large effects of renewable energy and nuclear cost inflation

caused by the range of techno-socio-economic factors

| Fig. 4.

Hourly electricity generation profile for the “Mix” case. Electricity consumption (mainly electrolyzers and battery charging) is shown as negative generation. NGCC

= Natural gas combined cycle; OCGT = Open cycle gas turbine; SMR CCS = Steam methane reforming with CO2 capture and storage.

19 https://extrudesign.com/what-is-technology-s-curve

20 https://energypost.eu/green-or-blue-hydrogen-cost-analysis-uncovers-which-is-best-for-the-hydrogen-economy/


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discussed above. The model is loosely based on Germany

and is designed to optimize investment and hourly dispatch

of a range of technologies, including:

p Nine different electricity generators: onshore and

offshore wind, solar PV, nuclear, natural gas combinedcycle

plants with and without CCS, open cycle gas

turbine peaker plants, hydrogen combined and opencycle


p Lithium-ion batteries for electricity storage

p Two clean hydrogen generators: steam methane

reforming with CCS (blue hydrogen) and electrolysis

(green hydrogen)

p Two hydrogen storage technologies: cheap salt

caverns with slow charge/discharge rates and locational

constraints and more expensive storage tanks without

such limits

p Hydrogen can also be imported in the form of

green ammonia that is reconverted to hydrogen in

reconversion plants included in the model

In addition, transmission costs for electricity, hydrogen,

natural gas, and CO 2 are included in the model.

p Electricity transmission is included only for wind and

solar generators, accounting for the distance between

demand centers and high-quality resources in publicly

accepted regions. The base case assumes 300, 500,

and 200 €/kW of added grid costs for onshore wind,

offshore wind, and solar PV, respectively.

p Hydrogen and natural gas transmission costs are

included for hydrogen- and natural gas-fired power

plants and steam methane reforming plants. Despite

natural gas pipelines being cheaper than hydrogen

pipelines, natural gas pipeline costs are set to 200 €/kW

relative to 150 €/kW for hydrogen because natural gas

needs to be imported from abroad, whereas hydrogen

is only transmitted locally between producers and


p Hydrogen transmission costs to locationally constrained

salt caverns are also included. These costs

are assumed to escalate from 100 to 500 €/kW as

capacity increases, accounting for the fact that

intermittently operated electrolyzers co-located with

wind and solar (see next point) will first exploit

sites close to salt caverns before more distant sites

need to be used.

p Electrolyzers are assumed to be co-located with

wind and solar plants to avoid the electricity

transmission costs mentioned in the first point. These

electrolyzers are assumed to avoid transmission

capacity costing 300 €/kW in exchange for added

hydrogen transmission costs of 150 €/kW. Since

electrolyzers consume more electricity than they

produce hydrogen, the net saving is about 200 €/kW of

transmission capacity – a substantial benefit.

p CO 2 transport and storage infrastructure costs are

added to CCS power and hydrogen plants. High costs

are assumed, given the high resistance to CCS in

Germany, amounting to levelized costs of 23 €/ton

when CCS plants are operated at the maximum

allowable capacity factor of 90 % (costs escalate

with lower capacity factors).

In the No CCS or Nuclear scenario, the electricity,

hydrogen, and natural gas transmission costs are

increased to 2x and 3x the default levels to account for

the following factors:

p The need to build turbines in more isolated sites or

far offshore to satisfy local stakeholders

p Avoiding public resistance to grid expansions via

expensive underground transmission lines

p Having to resort to sites with lower quality wind or solar


p Paying fees to local communities to allow construction

closer to demand centers

p Potentially large end-of-life recycling and disposal costs

of solar panels and turbine blades

p A sub-optimal buildout of the complex and highly

interdependent systems required to integrate high

shares of wind and solar

Costs related to ramping natural gas and nuclear power

plants are also included, amounting to 20 % of the total

annualized fixed cost in €/kW/year per MW of up or down


In all cases, total annual electricity demand is set to

the fluctuating hourly profile observed for Germany

in 2018, requiring a total of 499 TWh of production

per year. In addition, flat demand for hydrogen of

400 TWh/year and additional electricity (increased

electrification) of 200 TWh/year is included. This extra

hydrogen and electric energy is equivalent to about a

third of German non-power oil & gas consumption,

implying that great efficiency advances and more clean

energy deployment will be needed to reach net-zero


The GAMS software is used to minimize total system

costs by optimizing the deployment and hourly dispatch of

all production, transmission, and storage technologies. To

keep computational costs reasonable, only every 7 th hour

is simulated. A previous sensitivity analysis 21 has shown

that this assumption still yields accurate results.

As an illustration, hourly power production profiles

for the balanced Mix case are shown in Figure 4. The good

seasonal complementarity between wind and solar in

Germany is clearly observed. Nuclear’s baseload role is

also illustrated with electrolyzers and batteries mainly

responsible for balancing wind and solar power. Natural

gas power plants run only during isolated instances of high

demand and low renewable energy output.


Schalk Cloete

Research Scientist


Trondheim, Norway


Schalk Cloete is a research scientist working on solutions to our great 21 st -century

sustainability challenge: give every world citizen a fair shot at a decent life without

destroying the ecological carrying capacity of our planet. After reaching early

financial freedom, he retired from the research rat race and is currently 40 %

employed at the Norwegian research institute, SINTEF, where he develops novel

clean energy conversion technologies. His free-time research is dedicated to

policy and lifestyle design strategies for a rapid and just transition to a sustainable

global society.


21 https://www.econstor.eu/handle/10419/234469


Is Wind the Next Nuclear? ı Schalk Cloete

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“Since the Beginning, FORATOM has

Advocated for the Taxonomy to Follow

a Technology Neutral Approach.”

Interview with Yves Desbazeille ı Director General of FORATOM

Yves Desbazeille

Director General of FORATOM

Yves Desbazeille is French and graduated in electrical

engineering from the Ecole Supérieure d’Electricité (“ SUPELEC”)

in France in 1991 and studied on an MBA program in the early

2000s. During his successful career, he has been involved in

different businesses and responsibilities at EDF: nuclear

engineering, hydro and thermal power projects management in

France, USA as well as in Asia, where he was for 5 years. His

previous position as EDF representative for energy in Brussels

has provided him with an in-depth knowledge of the EU

institutions and Brussels’ stakeholders and of the energy and

climate stakes for Europe.

FORATOM is the Brussels-based trade association for the nuclear

energy industry in Europe. FORATOM acts as the voice of the

European nuclear industry in energy policy discussions with EU

Institutions and other key stakeholders. The membership of

FORATOM is made up of 15 national nuclear associations

representing nearly 3,000 firms.

The association provides information and expertise on the role of

nuclear energy; produce position papers, newsfeeds, responses

to public consultations, analyses of public opinion; organise

regular networking events like dinner debates, workshops, oneon-one

meetings, press briefings and visits to nuclear facilities.

For more than two years now FORATOM and other

industry associations, environmental organizations,

company representations and political institutions

were occupied with the EU Sustainable Finance

Initiative and the pivotal taxonomy of sustainable

activities. What were FORATOMs primary activities

in this respect?

The first action undertaken by FORATOM was to reach out

to all its members in order to draw attention to the file

under development and to invite them to share their

thoughts on how it could potentially impact the European

nuclear sector. This enabled the industry to develop its

position and desired outcome, providing FORATOM

with the tools to liaise with the EU institutions.

FORATOM furthermore established contact with other

stakeholders (including civil society) to inform them of the

European Commission’s plans and to share FORATOM’s


Since the beginning, FORATOM has advocated for the

taxonomy to follow a technology neutral approach. It

has constantly reiterated the message that, in order to

identify whether an energy source is sustainable or not, it

is important to evaluate each source on the basis of

objective criteria (including CO 2 emissions, air pollution,

raw material consumption and land use impacts) and

using a whole life-cycle approach. More information about

this can be found in our position paper “Sustainable

Finance: FORATOM calls for equal treatment of all lowcarbon


In terms of advocacy and outreach, FORATOM focused

on two elements:

p The so-called ‘Taxonomy Regulation’: Together with

its members, FORATOM established contacts with the

Council and nuclear supportive Members of the

European Parliament (MEPs). These two played a key

role in the decision-making process. In this respect, we

were successful in ensuring the Regulation underlines

the need for the taxonomy to be technology neutral.

p The Technical Screening Criteria of the taxonomy: At

the start of the process, FORATOM and its members

applied to form part of the technical expert sub-groups

established by the European Commission working on

this. FORATOM ensured close liaison with those on the

sub-groups by gathering all useful reports and studies

which supported the message that nuclear is sustainable.

Here the work proved very challenging as the

group included anti-nuclear organisations. Due to

a split position, the Technical Expert Group recommended

that nuclear be assessed by a group of experts

with an in-depth knowledge of the nuclear life cycle as

they did not feel that they had the right expertise. As a

result, nuclear was neither included nor excluded from

the taxonomy, and the Commission proceeded with

mandating its Joint Research Centre to conduct this


Following on from this, the JRC published its “Technical

assessment of nuclear energy with respect to the ‘do no significant

harm’ criteria of Regulation (EU) 2020/852 (‘Taxonomy

Regulation’)” at the end of March 2021. This report

was then reviewed by the following expert groups which

submitted their opinions on 2 July 2021:

p Opinion of the Group of Experts referred to in Article 31

of the Euratom Treaty on the Joint Research Centre’s


p SCHEER review of the JRC report on technical

assessment of nuclear energy with respect to the ‘do no

significant harm’ criteria of Regulation (EU) 2020/852

(‘Taxonomy Regulation’)


“Since the Beginning, FORATOM has Advocated for the Taxonomy to Follow a Technology Neutral Approach.” ı Yves Desbazeille

atw Vol. 66 (2021) | Issue 5 ı September

At the time of writing, FORATOM and its members

continue to liaise with the Member States and MEPs to

ensure that the Commission takes on board the conclusions

of the experts and proceeds with the inclusion of nuclear

under the taxonomy.

As nuclear received a special treatment with

dedicated specific reports, the third of which was

published in July, what were the arguments against

including this obviously low carbon, low environmental

impact technology both in the taxonomy

process and in the political battle fields around it?

Regarding the Technical Experts Group (TEG), and as

mentioned above, they made clear that they did not have

the right expertise to assess nuclear. We fully respect this

conclusion of the TEG, as

indeed for such scientific

decisions it is essential

that they are taken by

those with real expertise

in the field. But of course,

it meant that nuclear

found itself in a sort of

‘limbo land’ as it was

neither included nor excluded.

What was very

positive was that the TEG made it clear that nuclear

contributes to climate mitigation objectives.

The two areas where the TEG were less certain related


p Potential data gaps in relation to the Do No Significant

Harm criteria

p The long-term management of High-Level Waste


These are valid concerns, and as a result this is what the

JRC – as nuclear experts – was asked to focus on. The result

of this assessment has provided a clear response to both

these questions as follows:

p Based on the scientific evidence available nuclear does

not cause more harm than any of the other power

producing technologies currently deemed to be


p Deep Geological Repositories provide an appropriate

and safe solution for the management of HLW.

Against this backdrop there have of course been other

opinions expressed against nuclear. Here, a broad range of

arguments have been raised, including public opposition

to nuclear, the risk of proliferation, the impact of nuclear

accidents and radiation exposure. But it is our belief that

the work of the JRC experts provides a robust rebuttal to

these claims.

In the long-term, if certain policymakers are

successful in getting nuclear excluded from

the taxonomy for political reasons, this could

mean that nuclear no longer has access to

any form of finance, be it State Aid or private

investment. This would essentially spell the

end of the European nuclear industry.

What is actually at stake for nuclear in the sustainable

finance initiative and taxonomy?

There are two main issues at stake for the nuclear industry.

First of all, access to finance. The goal of this taxonomy

is to encourage investors to redivert funds towards those

activities classed as sustainable. Given that the nuclear

industry has high upfront capital costs, access to private

finance at an affordable interest rate is key. By encouraging

investors to move away from ‘non-compliant’ activities, a

political decision to exclude nuclear will severely hamper

its ability to raise funds for the financing of projects. Given

that companies will already be obliged to report on the

share of their activities which are taxonomy-(non)compliant

as of 1 January 2022, we already expect to see this

lack of clarity around nuclear having a negative effect not

just on utilities, but also large companies active in the

nuclear supply chain.

Secondly, it will have a broader political impact. EU

legislation is already being modified to align it to the

taxonomy. Take for example the recent EU recovery fund.

In order to access EU funds and loans under this package,

Member States have to put forward national Recovery and

Resilience Plans (RRPs). According to the legislation, 37 %

of the funds allocated must go towards taxonomy

compliant activities, and the Commission has already

confirmed to us that, as a decision on nuclear has yet to be

taken, nuclear related projects cannot count towards this

37 %. For the remainder of the funds, projects must meet

the Do No Significant Harm principle, again raising the

question as to how nuclear is to be treated under the RRPs.

It should be noted that the

EU is currently reviewing its

Climate, Energy and Environmental

State Aid Guidelines

and the pro posal on the table

makes a direct link to the

taxonomy, suggesting that

the EU is contemplating

reviewing its State Aid legislation

in order to align it to

the taxonomy...

In the long-term, if certain policymakers are successful

in getting nuclear excluded from the taxonomy for political

reasons, this could mean that nuclear no longer has access

to any form of finance, be it State Aid or private investment.

This would essentially spell the end of the European nuclear


Where are we now in the decision-making process

and what will happen next, who will decide what

in the end and who could block what?

The Council and the European Parliament are now being

asked to vote on the first Delegated Act (DA), which covers

the climate mitigation and adaptation aspects of the

taxonomy. These two institutions have two options: they

can either adopt or reject the DA. They cannot modify it.

The process being followed is called a ‘Scrutiny period’,

under which they have 4 months to take a decision (with

the potential to extend this by a further 2 months).

Whilst this DA covers technologies under the energy

sector, it does not include nuclear and natural gas. In this

respect, the Commission has

been waiting for the conclusion

of the nuclear assessment in

order to decide on whether to

include it under a complementary

Delegated Act (cDA).

This cDA is expected to be

made public anytime between

September and November

2021. Like other DAs, a draft

We understand

that discussions are

ongoing within

the Commission

as to what to do

with nuclear.

cDA will be published and subject to a one-month public

consultation. After this, the cDA will be sent for ‘scrutiny’

following the process mentioned above.

As to who could block what, this remains an open

question. First of all, because we understand that

discussions are ongoing within the Commission as to what

to do with nuclear. It has been suggested that some are

already pushing for nuclear to be excluded from the cDA

for political reasons, regardless of the fact that the experts

conclude that it is sustainable (and thus taxonomy

compliant). This is the first hurdle to be overcome.



“Since the Beginning, FORATOM has Advocated for the Taxonomy to Follow a Technology Neutral Approach.” ı Yves Desbazeille

atw Vol. 66 (2021) | Issue 5 ı September


Secondly, even if nuclear is added to the cDA, it is

possible that the Technical Screening Criteria are much

more stringent than those proposed in the JRC’s assessment,

thus making it virtually impossible for any project to

comply with them.

And finally, once it goes to the Council and Parliament,

we expect to see those who are against nuclear strongly

pushing for the cDA to be rejected.

Besides this major issue, other nuclear developments

have been going on. FORATOM has signed a

MoU with the Canadian Nuclear Association. What

are the major goals for this cooperation?

FORATOM is in the process of signing a series of

Memoranda of Understanding (MoUs) with several

national nuclear associations. The overarching goal of

these is to strengthen cooperation on an international level

and to promote nuclear as a clean source of energy. In

addition to the one signed with the Canadian Nuclear

Association (CNA), FORATOM is also in discussions with

the US Nuclear Energy Institute (NEI) and the Japanese

Atomic Industry Forum (JAIF).

The main focus of the MoU signed with the CNA is

to promote clean, innovative and advanced nuclear

technologies. In this respect, it focuses on the following:

p advocating for more explicit and

prominent inclusion of nuclear

energy in Europe and Canada’s

energy and environmental policies;

p support for innovation in nuclear

energy, specifically the development

and deployment of small

modular reactors and advanced reactors;

p Identify and implement initiatives where FORATOM

and CNA could work together to promote nuclear as a

clean energy source to meet climate change goals,

reduce emissions and improve the quality of life.

As the European trade association, FORATOM’s clear goal

is to influence EU policy. But as we all know, climate

change is a global issue and it is for this reason that we find

it essential to work with our partners at international level.

Some of the initiatives where FORATOM is playing a

greater role, together with its partners, include the UN

Climate Conferences (ie COP) and the Clean Energy

Ministerial (CEM) Nuclear Innovation: Clean Energy

Future (NICE Future).

At international level, it is also important to note that

for several years FORATOM has increased relations with

institutions such as the IAEA, the OECD-NEA. It is also

member of the “Global leader summit” gathering together

the Managing Directors of all these organizations

Likewise, it is important

to note that the existence

of the Euratom Treaty

might be threatened.

What are other topics on Brussels agenda that

concern the nuclear industry, like e. g. the Hydrogen

Strategy of the EU?

There are an increasing number of policy files which are of

direct relevance to the nuclear industry. Those which are

currently on the table and which FORATOM is actively

engaging in can be summarised as follows:

p Fit for 55 package: The main focus of this package is to

review existing legislation and align it with the EU’s

target of reducing CO2 emissions by at least 55 % by

2030 ( compared to 1990 levels). It covers a broad range

of legislation such as the EU’s Emissions Trading

Scheme and the proposal for a Carbon Boarder

Adjustment Mechanism, as well as a revision of the

Renewable Energy and Energy Efficiency Directives.

p Industrial strategy: This initiative looks at, for

example, how to reduce industrial emissions, whilst at

the same time maintaining industry’s competitiveness

including access to affordable energy. Workforce and

skills are also issues dealt with under this strategy.

p Energy System Integration and the Hydrogen

Strategies: These two strategies aim to support a more

efficient and interconnected low-carbon energy sector.

The goal is to ensure a constant supply and access to

low-carbon energy sources.

p Guidelines on State aid for environmental protection

and energy: As mentioned above, the EU is

looking to review these guidelines, including suggestions

of aligning them more closely to the Taxonomy


There are of course many other issues which FORATOM

is actively engaged in. For example, there are several

Innovation, Research and Development projects which

are under development and which receive EU support.

Developments relating to the Espoo and Aarhus

Conventions, respectively dealing with environmental

impact assessments and access to Information, public

partici pation in decision-making and access to justice in

environmental matters, also require constant monitoring,

because, despite not being purely nuclear, they can have a

serious impact on the nuclear activities.

Likewise, it is important to note that the

existence of the Euratom Treaty might be

threatened – indeed, in the latter instance

several Member States continue to push for

this Treaty to be reopened, modified and

potentially revoked....

Another topic that we are actively working on, even if it

is not related to one specific EU policy file, is the long-term

operation of the existing nuclear fleet. Given the stringent

decarbonization goals which the EU has set for 2030,

FORATOM strongly believes that more attention needs to

paid to this. As LTO (Long Term Operation) remains the

cheapest form of electricity across the board, prolonging

the existing fleet would be the best way of achieving the

2030 targets in an affordable manner.

In national energy policies we have seen some

major developments recently, such as Belgium

opting for nuclear phase-out and fossil gas phase-in,

the Polish nuclear program consolidating and a

very interesting debate about new nuclear power

in the Netherlands. Can you give us a brief overview

on these and possibly other developments of this

kind in the EU or in Europe?

With the UK leaving the EU, we have of course lost one of

the biggest nuclear advocates at Brussels level and this has

made our task a bit more challenging. But at the same

time, we are seeing other Member States pick up where the

UK has left off. For example, France has become much

more vocal in its defence of nuclear in relevant discussions.

Furthermore, several Eastern Member States have been

sending a very clear message to Brussels that in order to

achieve the ambitious climate targets set by the EU, nuclear

must be recognized as part of the solutions. Their main

For example, France

has become much

more vocal in its

defence of nuclear in

relevant discussions.

argument is that they have a

long way to go to decarbonize

their economies and

therefore they need to be

allowed to use all lowcarbon

technologies to

ensure that the transition is


“Since the Beginning, FORATOM has Advocated for the Taxonomy to Follow a Technology Neutral Approach.” ı Yves Desbazeille

atw Vol. 66 (2021) | Issue 5 ı September

both affordable and does not lead to a shortage in energy

supplies (nor increased dependence on energy and raw

material imports...).

Finland has always been supportive to nuclear, and it

has been very interesting to see that even the Finnish

Green party is taking a more pragmatic approach to

nuclear by recognizing that the fight we have today is

against climate change and that nuclear may form part of

the solution. Public opinion of nuclear in Sweden is also at

an all-time high.

The same can be said for the Netherlands, where they

are currently considering the development of a new

nuclear project as they recognize that it has a role to play in

terms of decarbonizing the energy sector and ensuring

security of supply. But of course, there are Member States

which remain staunchly anti nuclear, namely Austria,

Germany and Luxembourg. Belgium and Spain are also

increasingly leaning towards this more ‘anti’ camp.

What we can say, though, is that many are showing a

great interest in Small Modular Reactors (SMRs). One

example of this is Estonia, which is seriously considering

SMRs as a potential solution for their energy mix which is

currently very CO 2 intensive.

Quite a number of think tanks and international

institutions have stressed the importance of nuclear

for reaching climate policy goals, many governments

agree, including recently the Biden administration

in the US. Which position on nuclear will prevail in

EU institutions in your opinion, that of fundamental

critics aiming for phase-out sooner or later or of

nuclear optimists envisioning a long term and

possibly growing role in a low carbon energy


As indicated above, the EU remains very divided on the

issue of nuclear. The Treaties make it clear that each

Member State is free to choose its own energy mix, and

whether that includes or excludes nuclear is a national

prerogative. Of course, this does not prevent anti-nuclear

Member States trying to make

it as difficult as possible for

other to get nuclear projects

off the ground.

This discord is being felt

at EU level, with some

pushing for EU legislation

which de facto excludes nuclear.

Examples include the Just Transition Fund and

Invest EU, both of which automatically exclude nuclear

projects from having access to these funds without

providing any real justification for such an exclusion.

At the same time, many reputable organizations

continue to highlight the importance of nuclear in the fight

against climate change. Take, for instance, the latest IEA

report entitled ‘Net Zero by 2050’. According to this report,

nuclear energy will make “a significant contribution” in

the Net Zero Emission Scenario and will “provide an

essential foundation for transitions” to a net-zero emissions

energy system.

For us, it is essential that EU policy remain credible –

and this means basing policy on science. Let’s be clear: we

have less than 30 years to fully decarbonize our economy

and taking political decisions with no scientific justification

will lead us nowhere. This is why, as FORATOM, we

continue to insist that the EU adopt a technology neutral

approach to policy making which is based on the advice of

science and experts.

Let’s be clear: we have less than

30 years to fully decarbonize our

economy and taking political

decisions with no scientific

justification will lead us nowhere.

Given the opportunity, nuclear will be a help, not a

hindrance. Why?

First of all, because it is low-carbon and so it helps

achieve the decarbonization targets.

Secondly, it is available 24/7 and will ensure that

citizens and business have access to the energy they need

when they need it.

And finally: because it is affordable. Yes, nuclear project

come with high upfront costs. But they also have a long

lifespan of +60 years and require much lower system


Societal and political acceptance are key to the

application of nuclear power. But nuclear energy is

also a springboard for other political interests, not

power related. What are your expectations of

national and European policies to break this knot?

Nuclear power is indeed at the centre of many (heated)

debates at EU level. Most people are not actually aware of

the other solutions provided by nuclear. Let’s take, for

example, medical applications. The EU is a front runner

when it comes to the production of medical isotopes. And

yet very little is said about this – although let’s be clear,

many of those who are against nuclear energy are also

against its other applications....

As FORATOM, we are trying to draw more attention to

these other applications with, for example, the publication

of a position paper which focuses on medical uses of

nuclear technology, and which aims to respond, in part, to

the EU’s Beating Cancer Plan. We are also increasingly

highlighting the benefits which nuclear can bring in terms

of low-carbon hydrogen production, industrial applications,

space etc.

What people don’t necessarily realize is that legislative

proposals that aim to block nuclear energy could, in the

long term, also negatively affect these other applications.

For example, the taxonomy will in future cover other

sectors, potentially even healthcare. If nuclear power is

excluded, then this will potentially be used as an excuse to


also leave out all medical uses as well.

What we need is for the Member States

to continue to fly the flag for nuclear. They

play a key role in the EU decision-making

process. And in this respect, FORATOM

and its members stand ready to support

the Member States in any which we can.

Nicolas Wendler

Head of Media Relations and Political Affairs

KernD (Kerntechnik Deutschland e.V.)




“Since the Beginning, FORATOM has Advocated for the Taxonomy to Follow a Technology Neutral Approach.” ı Yves Desbazeille

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Operating Experience from Ageing

Events Occurred at Nuclear Power Plants

Antonio Ballesteros Avila and Miguel Peinador Veira

Introduction Nuclear safety of the operating nuclear power plants (NPP) has to be in the core of their life

management. NPPs have to be operated safely and reliably. European countries involved in nuclear energy are spending

their efforts in improving the safety of the operating plants and of those under construction, in accordance with the

Euratom Treaty obligations [Euratom Treaty, 2012]. In this respect, the IAEA requirements for the safe operation of

nuclear power plants identify, among others priorities, maintenance, testing, surveillance and inspection programmes

and ageing management of safety related components [IAEA, 2018].

Recognising the importance of peer

review mechanisms in delivering

continuous improvement to nuclear

safety, the amended Nuclear Safety

Directive [European Union, 2014]

introduced a European system of

topical peer reviews (TPR). The

subject “Ageing Management” was

chosen in 2017 as the first TPR exercise

on the basis of the age profile and

the potential long term operation

of European NPPs. The national

assessment reports [ENSREG, 2018]

prepared under this first TPR gave

numerous examples where operating

experience (OPEX) has been used to

inform ageing management. There are

many existing fora for sharing OPEX.

For example, the International Reporting

System (IRS) [IAEA, 2010]

and the International Generic Lessons

Learned Programme (IGALL) [IAEA,

2014] [IAEA, 2020] managed by the

IAEA, the Committee on Nuclear

Regulatory Activities (CNRA) and

the Committee on the Safety of

Nuclear Installations (CSNI) under the

OECD-NEA, and the European

Clearinghouse on Operating Experience

Feedback of the Joint Research

Centre (JRC) of the European

Commission [JRC, 2021] [Ballesteros

A., Peinador M., Heitsch M., 2015].

The original design life of structural,

mechanical and electrical components,

particularly those that technically limit

the power plant operation (e.g. reactor

pressure vessel, containment, etc.),

was originally estimated to be around

30-40 years, considering anticipated

operational conditions and ambient

environment under which they are

operated. In reality, the plant operational

conditions and ambient environment

parameters are below the limits

established during the initial design.

While economical feasibility falls into

the operating organization competence,

a decision regarding the plant

safety level depends on country’s

regulatory requirements. Generally, a

thorough technical assessment of

the plant physical condition is needed

to identify safety enhancements or

modifications, and the impact of

changes to NPP programmes and

procedures necessary for continued

safe operation.

Many operators in Europe have

expressed the intention to operate

their nuclear power plants for longer

than envisaged by their original

design. From a nuclear safety point of

view, continuing to operate a nuclear

power plant requires two things:

demonstrating and maintaining plant

conformity to the applicable regulatory

requirements; and enhancing

plant safety as far as reasonably

practicable. Depending on the model

and age of the reactor, national

regulators assume that granting longterm

operation programmes will

mean extending their lifetime by 10 to

20 years on average.

There are 106 nuclear power

reactors in operation in the European

Union (EU) in 13 of the 27 EU countries.

The age distribution of current

nuclear power plants is shown in

Figure 1. A major part of the EU

reactors are between 31 to 40 years

| Fig. 1.

Age distribution of the EU operating nuclear power reactors.

old. Hence, from both the safety and

security of supply viewpoints, ageing

of these power plants is of increasing

concern to European policy makers,

citizens and utilities.


The final objective of this work is to

draw case-specific and generic lessons

learned from ageing related events

occurred at NPPs during a period of

approximately 10 years. Namely,

events reported between 01/01/2008

and 30/06/2018 in the IAEA IRS

database. The IRS is an international

database jointly operated by the

International Atomic Energy Agency

(IAEA) and the Nuclear Energy

Agency of the Organisation for

Economic Cooperation and Development

(OECD/NEA). The IRS was

established as a simple and efficient

system to exchange important lessons

learned from operating experience

gained in nuclear power plants of the

IAEA and NEA Member States. The

IRS database contains more than

4500 event reports with detailed

descriptions and analyses of the

event’s causes that may be relevant to

other plants.

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Key word

Aging / ageing




“Irradiation damage”




“Material degradation”





| Tab. 1.

Number of event reports in the IRS database.

The screening of ageing related

events was carried out in two steps:

p Step 1: The query capabilities of

the IRS database are used to

retrieve an initial list of potentially

relevant events.

p Step 2: The reports obtained from

the previous step are briefly

reviewed to confirm their relevance.

Even if apparently relevant,

a report could be screened out if it

is insufficiently detailed or if its

quality is too low to be useful for

the purposes of the study.

The query result in the IRS database

for the period 01/01/2008 –

30/06/2018 was a list of 173 ageing

event reports (step 1), which were

reviewed to confirm their relevance.

The querying results are summarized

in Table 1, where the number of event

reports is given together with the

guide words used for the screening.

IRS allows querying ageing events

using the IRS code 5.7.5. But it was

noted that some ageing events were

not classified under this specific code.

For that reason querying was also

carried out by searching ageing events

using different degradation mechanisms

and their consequences.

After detailed analysis of the 173

event reports (step 2), only 113

reports were considered as relevant.

All the reports were thoroughly

reviewed in order to characterise the

events. To facilitate this process, the

events were classified according to

the following criteria: plant status, the

means of detection, the systems

affected, the components affected, the

Number of IRS event reports

(search is performed in the Root Causes section

of the IRS reports or in the full reports, depending

on the case. For Aging/Ageing the IRS criterion

5.7.5 is applied)

Search by the IRS Criterion 5.7.5: 60 events

+ 4 events related to Ageing no categorised as 5.7.5

6 in full report

7 in full report

31 in Root Causes

1 in full report

41 in Root Causes

21 in Root Causes

9 in Root Causes

5 in full report

24 in Root Causes

12 in full report

22 in Root Causes

173 event reports

(taking into account that the same report

may be retrieved with different key words)

direct cause, the root causes, the

ageing mechanisms, the conse quences

and the corrective actions. Further to

the classification of events, the reports

are also reviewed to identify the

aspects of the event that can be

used as feedback from operating

experience. These «low-level lessons

learned» are attached to specific

events, and generally can be understood

only in the context of those

events. For this reason, an effort has

been done to define «high-level

lessons learned», or simply «lessons

learned» defined in such a way that

they are not too specific (so that they

are applicable only to one single

plant) nor too wide (so that they can

be considered as common sense, and

already known to everybody).

Analysis of events

This section presents the result of the

screening and classification process

described above. The number of

events for each family in a given category

(plant status, detection, affected

system, affected component, direct

cause, root cause, ageing mechanism,

consequences, corrective actions) is

shown in Table 2.

It was interesting to calculate the

average age of the nuclear power

plant when the event occurred. This

can be expressed by:

Average Age =


n = final number of selected ageing


t 2 = time when the event happen

t 1 = time when the plant started


The analysis provides an Average Age

of 28 years (331 months) with a large

standard deviation of 10 years (123

months) and a median of 30 years

(357 months). In other words, on

average, ageing related events occur

after 28 years from the start of reactor


Selected event reports have been

characterised according to the criteria

defined for this study: plant status,

detection means, affected system,

affected component, direct cause, root

cause, ageing mechanism, consequences

and corrective actions. The

most relevant findings are highlighted


Plant status and

detection means

Figure 2 (left) shows the event distribution

related to plant status. Nearly

half of the events took place during

power operation. Figure 2 (right)

indicates that the major part of the

events were detected by “fault report

in control room” (58 %) followed by

“periodic test / in-service inspection”

(26 %). The fact that one of four

ageing events were detected in

periodic tests or in-service inspections

highlights the importance of having

sound inspection and maintenance

programmes to avoid sudden failures

during power operation with greater

implications on nuclear safety.

Systems and components


The distribution of events per system

affected is presented in Figure 3.

The largest percentage (36 %) corresponds

to the primary reactor systems,

followed by electrical systems

(21 %) and essential auxiliary systems

(13 %).

The distribution of events per component

affected is given in Figure 4.

Passive and active mechanical components

are the most affected components

(38 % and 34 %, respectively),

followed by electrical (16 %),

I&C (9 %) and structural components

(3 %).

Direct and root causes

Figure 5 indicates that the main direct

cause was mechanical failure. The

distribution of root causes is given

in Figure 6. A maximum of three

different root causes was attributed

to each event. Deficiencies in maintenance

or surveillance is the most

important root cause, followed by


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Plant status

N. events

Root cause

N. times


Power operation 54

Startup 7

Hot standby 2

Hot shutdown 2

Cold shutdown 12

Refuelling 20

Other or Unknown 16

Dectection of events

N. events

Periodic test / In service inspection 29

Fault report in control room 65

Work surveillance 6

Supplementary inspection 4

Other or Unknown 9

Affected system

N. events

Primary reactor systems 41

Reactor auxiliary systems 12

Essential service systems 1

Essential auxiliary systems 15

Electrical systems 24

Feed water, steam and power conversion systems 5

I&C systems 5

Service auxiliary systems 3

Structural systems 5

Other 2

Affected comp.

N. events

Passive mechanical components 43

Active mechanical components 38

I&C components 10

Electrical components 18

Structural components 4

Direct cause

N. events

Mechanical failure 83

Electrical failure 17

I&C failure 9

Structural failure 3

Other 1

Absent Ageing Managemet Programme 12

Deficiencies in Ageing Management Programme 25

Deficiencies in maintenance or surveillance 55

Wrong material selection 15

Equipment specification, manufacture, storage and installation 18

Deficiencies in design 30

Other or unknown 4

Ageing mechanism

N. times

Swelling 1

Relaxation 3

Fatigue 28

Thermal ageing 13

Irradiation damage 2

Corrosion 38

Wear 15

Erosion 4

Electrical ageing 15

Creep 1

Chemical ageing 1

Other 13

Unknown 3


N. events

Degradation (damage) 28

Deformation 12

Embrittlement and cracking 36

Material loss 30

Other or Unknown 7

Corrective Actions

N. times

Equipment replacement or repair 112

Monitoring and/or inspection improvement 39

Changes in operation modes 8

Changes in maintenance programme 50

Changes in ageing management programme 18

Design modification 25

Other 2

| Tab. 2.

Number of events/times per family.

deficiencies in design and in ageing

management programmes. To this

respect, we infer that the establishment

of an effective ageing

management programme, as early

as possible in the lifetime of the

plant, will significantly contribute to

preventing events and the resulting


Ageing mechanisms

The category “ageing mechanism”

was split in 13 families, as indicated

in Table 2, making it possible to

allocate several (maximum three)

ageing mechanisms to a single event.

Figure 7 shows that corrosion

(38 times) is the main cause of failure,

followed by fatigue (28 times). Other

important contributions are coming

from thermal ageing, wear and

electrical ageing.

As it will be showed later in the

section on lessons learned, many

events only appear after long term

operation of an aged component or

material, and the main cause was a

deficiency in design that was latent.

Figure 8 put some light on this issue

and illustrates that fatigue is the main

degradation mechanism in relation

to hidden deficiencies in design.

Figure 9 correlates deficiencies (or

absence) in ageing management

programme with the ageing mechanism.

In this case electrical ageing is

the most relevant contributor to

failure. This indicates the need for

improvement of the ageing management

programmes of electrical and

I&C components.

Consequences and corrective


Figure 10 shows the distribution of

events among different consequences.

36 events were related to embrittlement

and cracking and 30 events

to material loss (mainly due to


Figure 11 illustrates the corrective

actions. A maximum of three corrective

actions were allocated to a single

event. As expected, the main corrective

action was the replacement or

repair of equipment. Changes in maintenance

programme was the second

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| Fig. 2.

Plant status (left) and detections (right) means versus number of events.


| Fig. 3.

Number of events (%) per system affected.

| Fig. 4.

Number of events per component affected.

| Fig. 5.

Number of events per direct cause.

| Fig. 6.

Distribution of root causes.

most usual corrective action followed,

in this order, by monitoring or inspection

improvement, design modification

and changes in ageing

management programme.

Lessons learned

The extraction of the lessons

learned from the operating experience

has been completed in two steps.

First (step 1), low level lessons learned

were retrieved from the IRS database,

or developed in some cases, for a large

number of the 113 analysed events. A

total of 110 low level lessons learned

were obtained. They are given,

together with a short summary of the

events, in Annex 2 of reference

[ Ballesteros Avila A., 2019]. Several

lessons are allocated to the same event

in many cases. These low level lessons

learned are very specific, so that they

would have a too limited applicability.

To address this issue, the low level

lessons learned were grouped under

similar topic or underlying key

message to get a high level lesson

learned (step 2). In the following

paragraphs the high level lessons

learned are presented:

Lesson learned #1 – Appropriate

measures should be taken and design

features should be introduced in the

design stage to facilitate effective

ageing management throughout the

life of the plant.

Lesson learned #2 – Ageing

Management Programmes as well as

maintenance programmes should be

reviewed and updated to take into

account modifications in the current

licensing bases.

Lesson learned #3 – The monitoring

of the environmental conditions,

as information source for ageing

management, is of high importance.

In particular, a review of possible

changes in environmental conditions

(e.g. temperature, radiation, etc.) that

could affect ageing should be performed

in case of operational changes

or structures, systems and components

(SSC) modifications.

Lesson learned #4 – The maintenance

and inspection programmes

should be evaluated and, if considered

necessary, updated (frequency,

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testing methods, procedures, etc.) on

the basis of the findings of the ageing

management programme.

Lesson learned #5 – Ageing

management programmes for specific

degradation mechanisms should

| Fig. 7.

Ageing mechanisms present in the events.

| Fig. 8.

Deficiencies in design versus ageing mechanism.

be developed to avoid or mitigate

accelerated ageing (e.g., flow

accelerated corrosion, fretting, stress

corrosion cracking, thermal ageing).

It is important also to identify

and justify possible associated

| Fig. 9.

Deficiencies in ageing management programmes versus ageing mechanism.

changes in process conditions (e.g.,

flow pattern, velocity, vibration) that

could cause premature ageing and


Lesson learned #6 – The adequacy

and effectiveness of the inspection

and monitoring methods should

be periodically reviewed to maintain

plant safety and to ensure feedback

and continuous improvements of

ageing management. The evaluation

of technology and methods should

consider the need for detection of

unexpected degradation, depending

on how critical the SSC is to safety.

Lesson learned #7 – Adequate

oversight by the licensee is recommended

during all phases of design,

procurement, testing, receipt inspection

and installation to avoid events

where wrong material is used. When a

wrong or low performance material is

already installed, the rate of material

degradation can often be reduced by

optimizing operating practices and

system parameters.

Lesson learned #8 – Data on

operating experience can be collected

and retained for use as input for the

management of plant ageing. Reviews

of operating experience can identify

areas where ageing management

programmes can be enhanced or new

programmes developed.

Lesson learned #9 – Earlier

detection of degradation is necessary

to ensure timely application of mitigation

strategies. There is the possibility

that such early physical damage (e.g.,

change of locally averaged material

properties) can be detected with

appropriate sensors.

Lesson learned #10 – The operating

organization should ensure

that ageing management programmes

are reviewed on a regular basis and,

if needed, modified to ensure that

they will be effective for managing

ageing. Where necessary, frequently

as a result of reviewing operating

experience, new ageing management

programmes have to be developed.

| Fig. 10.

Number of events per consequence.

| Fig. 11.

Distribution of corrective actions.

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Ageing is a concern for the safe longterm

operation of NPPs. In particular

for the EU nuclear reactors, many of

them being between 31 – 40 years old.

In this respect, operating experience

from ageing events can contribute to

a great extent to enhance nuclear


The IRS database was screened to

select relevant events related to

ageing, which took place in the period

01.01.2008 – 30.06.2018. In total

113 events were analysed. The

analysis showed that “28 years” represents

the average age of a nuclear

power plant when the event occurred.

Deficiencies in maintenance or surveillance

is the most important root

cause, followed by deficiencies in

design and in ageing management

programmes. Corrosion is the main

degradation mechanism, followed by

fatigue. Other important contributions

are coming from thermal ageing,

wear and electrical ageing. Many

events only appear after long-term

operation of an aged component or

material, and the main cause was a

deficiency in design that was hidden.

110 low level lessons learned

( specific for the events) and 10 high

level lessons learned (generic) have

been obtained in this study. They

cover different areas, such as hidden

deficiencies in design, the impact of

ageing on maintenance and inspection,

deficiencies or lack of ageing

management programmes, use of

wrong material, etc.

This study highlights that the

continuous analysis of ageing related

events and the efficient utilization

of operational experience provides

important insights for improving the

quality of ageing management programmes

and for preventing the

occurrence of unusual events.






IAEA, 2010. IRS Guidelines, Joint IAEA/NEA International

Reporting System for Operating Experience, IAEA Services

Series 19, Vienna.


IAEA, 2014. Approaches to Ageing Management for Nuclear

Power Plants: International Generic Ageing Lessons Learned

(IGALL) Final Report, IAEA-TECDOC-1736, IAEA, Vienna.

IAEA, 2018. Specific Safety Guide No. SSG-48, Ageing

Management and Development of Programme for Long Term

Operation of Nuclear Power Plants, IAEA Safety Standards,




IAEA, 2020. Ageing Management for Nuclear Power Plants:

International Generic Ageing Lessons Learned (IGALL), Safety

Reports Series No. 82 (Rev. 1), IAEA, Vienna.



JRC, 2021. European Clearinghouse on Operating Experience





Ballesteros Avila

Scientific Officer

Joint Research Centre of

European Commission,

Petten, The Netherlands



Antonio Ballesteros is a Scientific Officer of the Joint

Research Centre of European Commission. He has

extensive experience in the fields of material science,

operating experience of nuclear power plants and

nuclear safety. Strong research professional with a

PhD in radiation embrittlement from the Kurchatov


Miguel Peinador Veira

Scientific Officer

Joint Research Centre of

European Commission,

Petten, The Netherlands



Miguel Peinador is a Scientific Officer of the Joint

Research Centre of European Commission. He has

experience in nuclear engineering, nuclear safety and

project management. He is currently leading the

European Clearinghouse on Operating Experi ence

Feedback of the Joint Research Centre (JRC)




Release of Radioactive


Provisions for Clearance

and Exemption

The new IAEA Safety

Guide DS500

on the “Application

of the concept of

clearance” is in the

process of endorsement

and will provide

detailed guidance on

the application of the

concept of clearance

for materials.



In cooperation with






Ballesteros A., Peinador M., Heitsch M., 2015. EU Clearinghouse

Activities on Operating Experience Feedback, BgNS Transactions

volume 20 number 2 (2015) pp. 93–95.


Ballesteros Avila A., 2019. Analysis of ageing related events

occurred in nuclear power plants, Topical Study from the EU

Clearinghouse on Operating Experience, Technical Report by the

Joint Research Centre of the European Commission, JRC119082.

ENSREG, 2018. First Topical Peer Review Report “Ageing

Management”, European Nuclear Safety Regulator’s Group



Euratom Treaty, 2012. Consolidated version of the Treaty

establishing the European Atomic Energy Community.



European Union, 2014. Council Directive 2014/87/Euratom

of 8 July 2014 amending Directive 2009/71/Euratom.



More information:



Operation and New Build

Operating Experience from Ageing Events Occurred at Nuclear Power Plants ı Antonio Ballesteros Avila and Miguel Peinador Veira

atw Vol. 66 (2021) | Issue 5 ı September



Ultra Safe Nuclear Corporation

Fully Ceramic Microencapsulated Fuel:

Possibilities and Prospect

An Historical Perspective on HTGR Fuel

High temperature gas-cooled reactors were conceptualized in the 1940s in

the U.S. (Daniel’s Pile) and ultimately realized in the 1950s in the UK (Dragon

Reactor). The various performance and safety benefits of these systems

could only be realized if a fuel system capable of retaining radionuclides at

high temperatures (> 1000°C) was possible.

In the late 1950s, the Dragon fuel developers abandoned

the vented fuel pin designs in favor of small spherical

coated fuel particles. Hence was born bi-, and

subsequently, tri-structural isotropic (TRISO) fuel

particles around which many of today’s advanced

reactors are designed. Decades of worldwide research

and development have resulted in a well-codified

basis of knowledge for manufacturing and performance

of the TRISO fuel form that is being leveraged in the

design and licensing of these reactors.

The high-temperature radionuclide retention capability

of TRISO fuel particles, coupled with reactor system

designs that allow passive heat removal during

off- normal conditions, are the basis of modern,

inherently- safe nuclear energy systems. Further

improvement in the radionuclide retention capability

and environmental stability of the fuel increase safety

margins, decreasing the necessary size of the ( Emergency

Planning Zone) EPZ. This is particularly important for

enabling economical distributed energy generation

using micro-reactors that are to be deployed in large

numbers (many hundreds or thousands).

New Possibilities with FCM®

Ultra Safe Nuclear Corporation (USNC) is the leading

developer of high temperature gas-cooled micro reactors

with its flagship Micro Modular Reactor, MMR. Key

to the design of the MMR, is its fully ceramic microencapsulated,

FCM®, fuel that comprises TRISO fuel

particles embedded inside of a refractory silicon carbide


FCM fuel was first conceptualized in 2010 by Ultra Safe

Nuclear Corporation (USNC) founder, Francesco Venneri,

along with scientists at Oak Ridge National Laboratory

(ORNL), and has undergone active research and

development since. USNC’s reactor technology was built

around this revolutionary fuel system and leverages its

immense safety and performance benefits to deliver

highly economic and inherently safe nuclear energy


The FCM fuel architecture is a major change from the

historic graphitic-matrix fuel forms and offers significant

benefits. The graphitic matrix exhibits complex irradiation

behavior (initially shrinks, then expands) and is only

able to retain its limited initial strength up to low doses.

The silicon carbide matrix, because of its well-known and

finite swelling behavior, is able to withstand very high

irradiation doses while retaining its configuration and its

strength. The graphitic matrix is also readily prone to

oxidation, making it susceptible to degradation in the

presence of trace amounts of air or moisture leaking into

the reactor coolant. The opposite is true for silicon

carbide as it exhibits exceptional air and steam oxidation


Finally, and most importantly, the porous, highly

inhomogeneous, and amorphous graphitic matrix does

not form a hermetic barrier to fission product release.

Silicon carbide, on the other hand, is the key constituent

in TRISO fuel responsible for the exceptional fission

At a Glance

Ultra Safe Nuclear Corporation

atw Vol. 66 (2021) | Issue 5 ı September


product containment within the fuel particles. When

employed as a matrix surrounding the fuel particles, it

provides a second highly effective barrier to any trace

radionuclide release that may arrive from the particles.

These benefits of FCM fuel represent a major evolution

in what is now possible in advanced nuclear energy

systems such as MMR.

FCM as a Flexible Fuel Architecture

In the past few years, advances in manufacturing

technologies, specifically three-dimensional (3D)

printing, have been applied to the production of silicon

carbide matrix FCM fuel. The use of 3D printing results

in the possibility of geometrically-unconstrained reactor

core designs, offering further improvements in performance

and safety.

FCM fuel, owing to the presence of multiple inherent

barriers to radionuclide release, offers a geologically

stable repository-ready fuel form. These barriers also

increase the difficulty of any attempts at clandestine

recovery of actinides, resulting in increased proliferationresistance.

In addition to the possibility of once-through disposal of

high burnup uranium based FCM fuel, FCM provides an

ideal route for disposition of waste from other reactors

through transmutation of transuranic elements (TRU).

TRU (Np, Pu, Am) from reactor spent fuel may be transformed

into TRISO and FCM fuel and optimally destroyed

(burned) in MMRs. The FCM compacts act both as a

robust fuel form for deep burning and as an ideal waste

form for permanent disposition.

FCM Manufacturing at Scale


The highly robust FCM fuel technology, and the

associated manufacturing methodology, are wholly

agnostic to the overall fuel geometry, type, and configuration

of the coated fuel particles. Therefore, FCM

fuel, as manufactured today, offers a fully flexible

architecture to enable efficient deployment in a range of

core designs and reactor systems. Some of these designs

benefit from other variants of coated particle fuel, such

as uranium nitride TRISO (instead of uranium oxidecarbide)

or BISO particles, that lend themselves to highly

compact or extraterrestrial-power systems.

USNC exclusively owns the intellectual property rights to

FCM fuel and associated silicon carbide 3D printing

technologies, leveraging them for design and deployment

of its various nuclear energy systems that include

and expand beyond MMR.

Repository Ready Fuel System

USNC is actively working on deployment of pilot and

commercial-scale manufacturing facilities for production

of FCM fuel. Two facilities in the United States (Salt Lake

City, UT and Oak Ridge, TN) are currently commissioned

and are undertaking pilot production activities. This

includes deployment and shakedown testing of

production modules for the various serial processing

steps to manufacture FCM fuel and full codification and

qualification of these modules.

USNC’s objective is the widespread deployment of safe,

clean, cost-effective, and reliable nuclear energy for the

benefit of humanity on earth and beyond. FCM fuel

technology is a core component of our value pro position.

We are working relentlessly to deploy large-scale

manufacturing of this highly robust fuel system and

invite partners who share our vision to join us in this


Kurt Terrani

Executive Vice President

Ultra Safe

Nuclear Corporation

USNC shares the vision of dramatically reducing the

radiotoxicity, volume, hazard index, and handling cost of

spent nuclear fuel originated from advanced reactors

and the current fleet of light water reactors. The high

radionuclide retention capability of the silicon carbide

matrix in FCM fuel, reduces radiological contamination

of core materials in advanced reactors. For example, the

large hexagonal graphite blocks in prismatic high

temperature gas-cooled reactors may only be disposed

of as low-level waste when they are fueled with FCM,

greatly reducing the waste volume.


Ultra Safe Nuclear Corporation





At a Glance

Ultra Safe Nuclear Corporation

atw Vol. 66 (2021) | Issue 5 ı September




Fuel Design Advancements

Derek Wenzel, Uffe Bergmann and Juan Casal

The article presents recent advancements of the Westinghouse PWR and BWR fuel products and focuses on new

design features that are targeted to further improve the fuel reliability and performance in the near future.

Introduction PWR fuel

Westinghouse currently supplies fuel

to more than 100 PWR plants

worldwide consisting of 14x14, 15x15,

16x16, and 17x17 Westinghouse

NSSS, Combustion Engineering (CE)

16x16, KWU designs, and VVER fuel

designs. Design improvements have

been completed over the years to

enhance reliability, mitigate fuel

leakers, and address other fuel

related issues such as fuel distortion,

handling damage, and control rod

insertability. Theses advancements

have significantly improved fuel

performance in all PWR designs. As an

example, the con tinued use of the

Westinghouse NSSS design’s multilayer

debris protection with the Debris

Filter Bottom Nozzle (DFBN), Robust

Protective Grid (RPG) and fuel rod

oxide coating has mitigated debris

fretting leakers in the interior of the

fuel assembly. However, there are still

periodic peripheral rod leakers due to

the debris path between assemblies.

To combat the periodic peripheral

rod leakers, Westinghouse has developed

two different types of innovative

Advanced Debris Filter Bottom

Nozzle (ADFBN) designs. The development

of the first ADFBN design

has been deployed in several US

reactors. Through extensive testing,

the ADFBN design has been proven to

significantly reduce the debris leakage

path between assemblies and further

prevent peripheral rod leakers. A

follow up advanced nozzle has been

designed for additive manufacturing

(AM) processing to create complex

debris path traps to dramatically

improve debris filtering capability. The

AM design has shown significant debris

filtering improvement through rigorous

debris test simulations. Westinghouse

has incorporated this additional debris

protection techno logy into part of the

PRIME fuel design, which packages

multiple feature enhancements together

to improve fuel performance

and reliability that also support higher

burnups. These PRIME features are

being delivered in region quantities

beginning in 2021.

PRIME fuel description

The PRIME fuel design is built upon

the overall excellent performance

history of Westinghouse NSSS fleet

including 17x17 OFA, 17x17 RFA/

RFA-2, and 15x15 Upgrade fuel

designs. The PRIME fuel design

incorporates three new hardware

features. The first feature is the transition

from ZIRLO® grids to Low Tin

ZIRLO grids. The second feature is

the use of the reinforced dashpot

| Fig. 1.

Advanced PRIME Features.

design. The third feature is the use of

the PRIME bottom nozzle, which

utilizes the ADFBN side skirt filter

technology and also implements a

lower pressure drop feature. All three

PRIME features are adopted into the

existing skeleton design to further

advance fuel performance while

maintaining fuel reliability.

The PRIME fuel design features

are shown in blue font in Figure 1



Westinghouse Fuel Design Advancements ı Derek Wenzel, Uffe Bergmann and Juan Casal

atw Vol. 66 (2021) | Issue 5 ı September


| Fig. 2.

Tube-in-Tube Dashpot Assembly Design Schematic.

| Fig. 3.

Swaged and External Dashpot Assembly Design Schematics.

Improved grid strap material

Low Tin ZIRLO material has been

chosen as the latest alloy to be used for

Westinghouse grids. This material has

lower tin content as compared to

standard ZIRLO, which provides for

enhanced performance with regard to

corrosion and grid growth. Westinghouse

has successfully implemented

similar Low Tin ZIRLO materials in

fuel rods in many reactors and the

rods have shown significantly reduced

oxide as compared to standard ZIRLO

and Zr-4 rod materials.

Improved skeleton stiffness

Many nuclear utilities have expressed

their interest in high burnup operation

that provides fuel economics

savings through increased cycle

lengths and fewer outages. However,

high burnup operation leads to fuel

performance limitations including

fuel distortion that could result in

incomplete rod insertion (IRI) concerns

as experienced back in the early

1990s in some plants. An IRI event can

occur when the control rodlet cannot

be fully inserted in the guide thimbles

of the fuel assembly due to excessive

drag force between the guide thimble

or dashpot tube inner surface and

control rodlet. Many factors contribute

to an IRI event including

fuel assembly dimensional stability.

Westinghouse has eliminated those

IRI concerns through introduction of

the RFA fuel design with ZIRLO

material, thicker guide thimble walls

and the tube-in-tube design with no

IRI performance issues reported.

To address potential fuel performance

limitations regarding

fuel distortion during high burnup

operation, Westinghouse has implemented

incremental skeleton stiffness

enhancements through development

of the reinforced dashpot design. The

new design provides additional

resistance to distortion in the dashpot

region during high burnup operation.

It is critical to provide higher distortion

resistance in the dashpot area

of the thimble tube since the dashpot

region has minimal clearance between

the control rodlet and the inner

surface of the thimble tube.

Two reinforced dashpot designs

were selected to improve skeleton stiffness

in the dashpot region for the

PRIME fuel package. The first chosen

reinforced dashpot design is the

existing tube-in-tube design, shown

in Figure 2, due to its positive field

experience and availability for fuel

designs ranging from 14, 15, and

17 RFA and 17XL RFA arrays. However,

it has not been universally implemented

across the Westinghouse NSSS

designs. The tube-in-tube dashpot

assembly design consists of a constant

diameter outer thimble assembly and

a separate internal dashpot assembly.

The second chosen reinforced dashpot

design is the external dashpot tube

design shown in Figure 3. The external

dashpot assembly is retro fitted into the

existing 17x17 OFA swaged guide

thimble assembly without any hardware

changes to the fuel assembly

skeleton hardware to minimize additional

changes to the 17x17 OFA fuel

design, which has performed exceptionally

over the years. The external

tube is placed between the bottom grid

and the bottom-most mid grid before

the swaged transition as shown

in Figure 3. The external tube is

mechanically fastened with two

restraint bulges to connect the external

dashpot tube to the guide thimble

tube. The external dashpot design

is exclusively part of the PRIME

17x17 OFA design.

Improved debris filtering

The debris protection features for

Westinghouse NSSS PWR fuel have

provided very good performance

historically with respect to debris

fretting leakers. These multi-layer

debris protection features are

illustrated in Figure 4. The historical

Debris Filter Bottom Nozzle (DFBN)

design had small flow hole sizes and is

designed to mitigate debris-induced

fuel rod fretting leakers by preventing

debris from entering the fuel assembly.

The Robust Protective Grid (RPG)

traps any debris that passes through

the DFBN against the elongated solidfuel-

rod-bottom end plug avoiding

penetration of the clad. Oxide coating

over the bottom six inches of each fuel

rod increases the surface hardness,

thus increasing wear resistance over

uncoated cladding.

| Fig. 4.

Proven Multi-layer Debris Protection Features.


Westinghouse Fuel Design Advancements ı Derek Wenzel, Uffe Bergmann and Juan Casal

atw Vol. 66 (2021) | Issue 5 ı September


PRIME bottom nozzle

The PRIME Bottom Nozzle design is

comprised of an improved top flow

plate and a lower side-skirt so that the

bottom of the skirt is 0.125 inch from

the lower core plate. The lowered

side-skirt avoids any interferences

with lower core plate protrusions

from any Westinghouse NSSS plant

and has demonstrated significant filtering

improvement over traditional

DFBN side-skirts through extensive

flow testing. The PRIME Bottom

Nozzle also been developed to incorporate

an optimized flow hole feature

to provide an added benefit to reduced

pressure drop relative to the existing

| Fig. 6.

Additively Manufactured (AM) Bottom Nozzle.

| Fig. 5.

PRIME Bottom Nozzle Optimized Flow Hole

Features to Reduce Pressure Drop.

| Fig. 7.

Additively Manufactured Bottom Nozzle Top Plate Filter.

DFBN designs. The top plate flow hole

has been optimized to incorporate a

double inlet and single outer chamfer

as shown in Figure 5, which provides

additional thermal-hydraulic performance

margin to the fuel assembly.

Additively manufactured

bottom nozzle

The AM Bottom Nozzle design, shown

in Figure 6, is made from Alloy 718

and utilizes a lowered skirt similar to

that of the PRIME Bottom Nozzle with

a top flow plate that dramatically

reduces the size of debris that can pass

through to the fuel rods. The additive

manufacturing process has the ability

to create high fidelity geometries

with high strength alloys, such as

Alloy 718, to enable the possibility of

creating this complex top flow plate.

Since the AM Bottom Nozzle is

made from a much stronger material

(Alloy 718) than current bottom

nozzles, which are made from stainless

steel, the thickness of the structural

members can be minimized which allows

for more overall flow area

through the top flow plate and reduces

the pressure drop of the structural

portion of the top flow plate. Complex

debris filtering features are added

between the structural members to use

the pressure drop margin to provide

dramatic improvement in top plate

debris filtering – reducing the size of

the debris that can pass through the

top flow plate by a factor greater than

10 and thereby render it harmless. The

specific concept used for the AM

Bottom Nozzle is the double spire (i.e.,

two meshes used), shown in Figure 7.

The two spires (or meshes) are offset

from each other to provide maximum

debris filtering capability. The AM

Bottom Nozzle design is planned to be

deployed in lead use fuel assemblies in

2022. The AM Bottom Nozzle design is

not part of the PRIME fuel design but

is an option to replace the PRIME

Bottom Nozzle to provide further

advanced debris protection.

BWR fuel product development

In the continued strive to offer Fuel

Products with additional value both in

terms of performance and reliability

to the BWR plants, Westinghouse

has pursued the development of the

TRITON11® fuel, a new 11x11-rods

design concept, as well as the new

StrongHold® fuel inlet debris filter to

be used in the Westinghouse SVEA-96

Optima3 and TRITON11 BWR fuel


Given the current economic

pressure on the utilities, the key

| Fig. 8.

TRITON11 fuel design.

development objective of TRITON11

was to significantly reduce the fuel

cycle costs, together with the ability of

meeting the varying requirements

between the different BWR utilities

(such as extended cycle lengths,

power uprates and higher burnups),

while minimizing the risk of fuel leakers.

TRITON11 is the greatest leap in

Westinghouse BWR fuel innovation

since the introduction of the SVEA

concept in the early 1980’s. The

fuel assembly mechanical design for

Nordic ASEA-type reactors is shown in

Figure 8. In total, there are 109 fuel

rods: 91 fuel rods of full length, 10

part-length rods of approximately 1/3

length and 8 part-length rods of

approximately 2/3 length. All fuel

rods are resting freely on the bottom

tie plate and laterally supported by

10 spacer grids of the same sleevetype

design as used in SVEA-96

Optima 3 fuel. Three cylindrical water

channels referred to as water rods

provide non-boiling water for improved

moderation in the interior part

of the fuel bundle.

The TRITON11 fuel assembly

design has been verified by out-of-pile

testing and analyses to fulfill all

requirements for insertion of Lead

Test Assemblies (LTAs) in a nuclear

plant. This includes all mechanical,

thermal-hydraulic, and nuclear design

features as well as the ability to safely

transport the fuel in channeled condition

and the ability to perform

reliable fuel service, inspection, and

repair. The verification scope has been

significantly extended by use of more

advanced testing techniques and

analysis methods to gain further

insight in the behavior of the new

design. All manufacturing processes

for the first LTA deliveries have been

tested, verified, and qualified to meet

the high-quality standards and

efficiency recognized in Westinghouse


Westinghouse Fuel Design Advancements ı Derek Wenzel, Uffe Bergmann and Juan Casal

atw Vol. 66 (2021) | Issue 5 ı September


| Fig. 9.

Visual inspection of the upper part of the TRITON11 assembly.

Derek Wenzel

Manager, Product &

Process Operations

Nuclear Fuel Engineering

and Parts

Westinghouse Electric


Columbia, SC, USA




Dr Uffe Bergmann

Consulting Engineer



Global Technology Office

Westinghouse Electric

Sweden AB



| Fig. 10.

Left: StrongHold debris filter inlet side. Right: StrongHold AM debris filter inlet side.

products. The 18 LTAs, initially loaded

in two Nordic plants in 2019, included

in the in-pile demonstration program

for TRITON11, completed their

second annual cycle of operation in

May 2021. Poolside inspections

performed in both plants after one

and two years of operation, including

visual examination and dimensional

measurements on fuel bundles and

channels, have verified the anticipated

behavior, as exemplified in

Figure 9 for the upper part components.

As a response to the growing

concerns about debris fretting

leakers in BWR fuel, Westinghouse is

launching its new StrongHold debris

filter. The debris capture efficiency

of this new filter design was finely

optimized using a new enhanced

testing methodology. Further improvements

in capture efficiency were

obtained by utilizing the flexibility

of Additive Manufacturing (AM) to

create an extraordinary design

referred to as StrongHold AM. Both

filter designs have been proven to

capture thin metal wires, of any shape,

with 100 % efficiency down to a wire

length of 7 mm - and even lower for

the StrongHold AM filter. The now

completed out-of-pile testing and

verification of both designs included

testing of debris capture efficiency

and post-LOCA clogging, filter pressure

drop and filter mechanical

endurance. The StrongHold filter

showed additional margin, relative to

the previous TripleWave+ filter,

against clogging by the type of debris

that may be released during a LOCA.

StrongHold is based on the same

basic geometry as the TripleWave+

debris filter with a central wavy

obstacle. By introducing additional

perpendicular plates, the flow is split

into narrow square-shaped flow

channels as can be seen in Figure 10.

The version of the StrongHold debris

filter shown in the left panel is conventionally

manufactured by cutting and

stamping metal plates, assembling,

and welding. The more advanced

StrongHold AM version, shown in the

right panel, is built in one piece from

metal powder by use of AM technology.

The added mechanical

strength from the all-internal “welds”

of StrongHold AM filter enables a

reduction of the wall thickness. The

resulting reduction in pressure

drop enables some enhanced design

features that further improve its

capture efficiency for very short wires,

by topology optimization.

Both variants of the StrongHold

filter design will greatly reduce the

risk of debris fretting leakers in future

deliveries of SVEA-96 Optima3 and

TRITON11 fuel assemblies.



StrongHold and HiFi are trademarks or registered trademarks

of Westinghouse Electric Company LLC, its affiliates and/or its

subsidiaries in the United States of America and may be registered

in other countries throughout the world. All rights reserved.

Unauthorized use is strictly prohibited. Other names may be

trademarks of their respective owners.

Juan J. Casal

Customer Solutions and

Product Manager

Fuel Hardware (BWR)

and Engineering Services

EMEA – Operating Plant


Westinghouse Electric

Sweden AB




Westinghouse Fuel Design Advancements ı Derek Wenzel, Uffe Bergmann and Juan Casal

atw Vol. 66 (2021) | Issue 5 ı September


Kazatomprom and the Nuclear Fuel Cycle

Mazhit Sharipov

As it is well known, Kazakhstan has significant natural uranium reserves, ranking second in the world (15 %) after

Australia (28 %). Since 2010, Kazatomprom (the National Uranium Operator) has been the leading producer of natural

uranium (yellowcake) in the world, which has provided Kazakhstan with a 41 % share of global production.

Kazatomprom also seeks to expand its presence in other parts of the global nuclear fuel market.

| “ULBA-FA” LLP fuel assemblies production line.

Kazatomprom is systematically working

to achieve and maintain the status

of a Preferred and Reliable Partner

for the global nuclear industry over

the long-term. At the same time,

attention is paid to compliance

with the principles of Sustainable

Development and ESG (environment,

social responsibility and governance).

Kazatomprom is currently developing

its uranium deposits using

the in-situ recovery (ISR) method,

which is both the most environmentally

friendly and most costeffective

method of uranium mining.

Since 2018, the Company has also

been the global leader in uranium


NFC projects

Kazatomprom is interested not only in

the extraction and supply of natural

uranium, but also in the production

and sale of more refined uranium


The advantages of the chosen

direction are the development of

technologies for creating uranium

products with higher added value, the

expansion of export potential, the

possibility of offering a complex

product on the global market and the

development of new sales channels.

Uranium processing

Ulba Metallurgical Plant (UMP) with

its long history, technology and

capacity, as well as its qualified

| Area for preparing press powders to be used

for production of fuel pellets.

| Fuel pellets.

engineering and technical personnel,

was appointed as the key uranium

processing enterprise for the development

of the Kazakhstan’s nuclear fuel


Currently, UMP is one of the largest

manufacturers of uranium, beryllium

and tantalum products. It has more

than 70 years of experience in the

production and supply of high-tech,

world-class products that are used

in the nuclear, aviation, and space

industries, as well as in electronics,

medicine, instrumentation, science

and many other leading industries.

Today, uranium production at

UMP includes the production of U 3 O 8 ,

uranium dioxide powders from a

variety of raw materials (refining and

| Checking up the diameter of fuel pellets.

| Administrative building of Ulba Metallurgical Plant.

| Fuel pellets sintering area.


Kazatomprom and the Nuclear Fuel Cycle ı Mazhit Sharipov

atw Vol. 66 (2021) | Issue 5 ı September

isotopic enrichment products, as

well as fuel fabrication by-products)

and fuel pellets. Uranium products

are certified by and supplied to the

largest fuel producers in the world in

countries throughout North America,

Europe and Asia.

UMP is also mastering the production

of new products and is

carrying out certification processes in

various countries. For the past

10 years, UMP has been manufacturing

and supplying fuel pellets to China

factories and there are also long-term


The enterprise seeks to adapt its

products to new requirements and

it is therefore upgrading the pellet

production process.

UMP has completed the re-qualification

of its fuel pellet production

for French designed AFA 3G type fuel

assemblies, and it has polished the

technology for the production of fuel

pellets for other types of westerndesign

fuel assemblies. In the very

near future, it is expected that the processes

used in UMP's technological

line will be certified with the further

setting up the production of new

design fuel pellets and their supply to

new markets.

Participation in uranium


Demonstrating adherence to the

principles of nonproliferation and

strictly adhering to the Nonproliferation

Treaty, obligations to the

| Launching Kazakhstan and Russia’s joint

project on uranium enrichment, 2013.

| Enriched uranium cylinder.

IAEA and international agreements

signed by Kazakhstan, Kazatomprom

implemented a project on uranium

enrichment in Russia.

At present, a joint project with the

Russian party is being carried out on

the basis of the world’s largest Russian

uranium enrichment enterprise – the

Ural Electrochemical Combine. Since

2014, the Kazakhstan-Russian joint

venture Uranium Enrichment Center

JSC had access to Russian uranium

enrichment services in the amount of

5 million SWU (separative work units)

per year.

This makes Kazatomprom a participant

in the enrichment market and

provides guaranteed access to one of

the most important stages of the

nuclear fuel cycle, without which it is

impossible to manufacture nuclear

fuel for nuclear power plants.

Plans for a refinery project

As part of the agreements reached

between Kazatomprom and the

Canadian company Cameco Corporation

in 2020, technologies for the

refining and conversion of uranium

were obtained. At some point in

the future, Kazatomprom plans to

implement a project at the UMP site

for the construction of a refinery using

the obtained technology.

It should be noted that the creation

of a refinery, which is a nuclear purity

U 3 O 8 production facility is intended

to minimize the environmental impact

in the region by eliminating the discharge

of liquid waste, the release of

associated gases and to reduce the

consumption of hazardous chemicals

during the processing of natural

uranium concentrate.

During 2020-2021, an assessment

of the technical capacity and economic

feasibility of such a project was

completed, which resulted in positive

conclusions. Currently, Kazatomprom

and UMP are starting to develop

| “Ulba-FA” fuel assemblies plant.

| Fuel assembly.

design documentation for the eventual

construction of a refinery.

In the future, Kazatomprom also

plans to consider the economic

feasibility of establishing a conversion

facility in Kazakhstan.

Nuclear fuel assembly

production project

Since 2015, a joint Kazakhstan-

Chinese project has been underway to

establish a facility for nuclear fuel

assembly production in Kazakhstan.

The goal of the project is to produce

200 tons of certified French design

AFA 3G fuel assemblies (FA) per year

(enriched uranium) for the reactors

operated by CGN in China.

The project is a unique and positive

example of multilateral, mutually

beneficial cooperation in the field of

nuclear energy, since companies from

Kazakhstan, China, France, USA and

Germany took part in the project.

In 2015, joint venture Ulba-FA LLP

was established (the founders: UMP –

51 %, CGNPC-URC – 49 %) for the

creation and further operation of

a nuclear fuel production plant on

the territory of the Republic of

Kazakhstan, to Chinese nuclear power


During 2015-2020, major efforts

were taken; agreements were

reached and documented between

Kazatomprom and CGNPC-URC on

the main principles and mechanisms

for the project implementation. The

joint venture Ulba-FA LLP received the



Kazatomprom and the Nuclear Fuel Cycle ı Mazhit Sharipov

atw Vol. 66 (2021) | Issue 5 ı September


| Skeleton production area.

| Fuel assembly.

technology for the production of

FA with the AFA 3G design from

Framatome; the project documentation

on the FA plant was developed;

contracts were signed with the companies

from France, China and the

Republic of Kazakhstan for the

| Ceremony of signing the agreement on establishment of the IAEA LEU Bank.

manufacture of technological equipment,

as well as the issues on the

supply of components and uranium

raw materials required for production

of fuel assemblies are resolved.

At present, the construction of the

fuel assembly facility has come to the

final stage. This means that a unique

enterprise – a plant for the production

of nuclear fuel for nuclear plants – will

soon start operating in Kazakhstan.

Ulba-FA LLP completed all general

construction work and installation of

high-tech equipment; commissioning

of the entire pro duction line was carried

out and training of technical personnel

was organized. The fuel assembly

plant was accepted for operation

in 2020. All the necessary state licenses

(permits) were obtained to carry

out the declared activities in the field

of atomic energy use (nuclear fuel

production). The audit of the quality

management system by the end user

of the plant’s products has been

successfully passed.

Due to the coronavirus pandemic,

the deadline for completing the

qualification carried out jointly with

Framatome has been rescheduled. At

the moment, all work is on schedule

and the first pilot fuel assemblies have

now been manufactured. Commercial

production of fuel assemblies is

expected for the end of 2021, and in

accordance with the long-term

contract, the first deliveries of finished

products will be carried out next year.

Fuel pellets manufactured at

UMP will be used to fabricate fuel

assemblies at Ulba-FA LLP. Their

production was established more

than 10 years ago and certified for

compliance with the requirements of

nuclear fuel buyers and the developer

of the fuel pellet design.

The creation of the front-line

step of the nuclear fuel cycle in

Kazakhstan – the manufacture of

fuel assemblies – will help to realize

Kazatomprom’s longer-term strategic

goal of investing in processing and

other NFC stages to generate longterm

value for the Company. As a

result, a modern and fully automated

production process will be established

at UMP.

Non-proliferation Projects

Kazakhstan is rightfully recognized

as the leader of the non-proliferation

regime and, being a member of

the Treaty on the Non-Proliferation

of Nuclear Weapons (NPT), is actively

working to further expand the

peaceful use of atomic energy for the

benefit of humanity, to strengthen the

nuclear non-proliferation regime, and

to improve the level of international



Kazakhstan, supporting the IAEA initiatives

aimed at strengthening global

nuclear safety, together with the

Agency, imple mented a project to create

a Low Enriched Uranium Bank

(LEU Bank) on its territory, and Kazatomprom

took an active part in the


This project is one of the most

significant multilateral projects in

the field of non-proliferation and of

mass destruction weapons.

The LEU Bank was established

under the auspices of the International

Atomic Energy Agency

(IAEA) to ensure guaranteed supplies

of nuclear fuel to nuclear power plants

of the IAEA member states and is a

storage facility for low enriched

uranium, which is the starting

material for the manufacture of fuel

for nuclear power plants.

The purpose of creating the

LEU Bank is to ensure the efficient

functioning of the international

nuclear fuel market on a permanent

basis, so that states using nuclear

power or considering the possibility of

its inclusion in the structure of of their

energy production have confidence

that they will be able to obtain nuclear

fuel in a guaranteed and predictable


On August 29, 2017, an official

ceremony of completion of the construction

of the LEU Bank building

was held with the participation of


Kazatomprom and the Nuclear Fuel Cycle ı Mazhit Sharipov

atw Vol. 66 (2021) | Issue 5 ı September

| Uranium hexafluoride cylinders.

| IAEA LEU Bank building.

| Supply of low enriched uranium

to the LEU Bank.

the President of the Republic of

Kazakhstan, the Director General of

the IAEA and other officials of foreign

states and international organizations.

In 2019, the delivery of materials

in the amount of 90 tons of low

enriched uranium in the form of

uranium hexafluoride was organized

to supply the LEU Bank, which is

located at the secure UMP site. This

volume does not exceed 10 percent of

the amount of uranium that was previously

stored at UMP as its own

production reserves.

The LEU Bank reached the operating

stage in 2020, with UMP as the

operator providing all conditions for

the safe storage of LEU.

The placement of the IAEA nuclear

material bank at the UMP recognizes

the high level of safety at the plant

that meets the strictest international

criteria, the qualifications and experience

of workers, and the quality

of the enterprise’s performance.

HEU to LEU processing

In 1999, after 25 years of trouble-free

operation in Kazakhstan, the BN-350

fast neutron reactor, which used

highly enriched nuclear fuel, was shut


In addition, research reactors

running on highly enriched fuel

are being operated in Kazakhstan.

Since Kazakhstan is systematically

fol lowing the course of non-proliferation

and nuclear safety, it is taking

measures to reduce fuel enrichment

in order to liquidate the entire available

stock of highly enriched uranium


For these purposes, over the

period of more than 20 years, joint

trilateral projects are being implemented

between Kazakhstan, the

USA and the Russian Federation to

convert HEU to low enriched uranium


Within the framework of this

project, UMP has developed a technology

for the processing of HEU in

various aggregate states and at

different levels of enrichment (to LEU

with an enrichment of less than

19.5 %), and identified a site to

establish a processing facility.

The conversion of HEU to LEU was

successfully completed. Technologies

developed by Kazakhstan specialists

are highly appreciated by experts

from the IAEA and the US Department

of Energy.

The safe shutdown of the BN-350

reactor and the continuation of

the conversion of fuel for research

reactors in Kazakhstan from HEU

to LEU, significantly contributes to

international security and the nonproliferation

of nuclear weapons.


Thanks to the implementation of its

NFC projects, Kazatomprom not only

creates new production facilities, but

also acquires new knowledge and

competencies while improving the

qualifications of its specialists, and

adopting the best practices in the

nuclear field from the world’s leading


The implementation of multilateral

projects makes it possible to

expand interaction between companies

from different countries, where

working together on a specific project

in real practice allows experts to

exchange knowledge and experience,

which ultimately is a good example of

international cooperation.

Thus, while maintaining its

leadership in uranium mining,

Kazatomprom is working also to

establish new NFC production facilities

in the Republic of Kazakhstan, for

the production of more refined and

more valuable uranium products. This

is expected to allow the company to

strengthen its position in the global

nuclear market over the longer-term,

and expand its presence in other

stages of the nuclear fuel cycle.


Mazhit Sharipov


Nuclear Fuel Cycle Officer

National Atomic


Kazatomprom JSC


Mazhit Sharipov graduated from the Obninsk Institute

of Nuclear Power Engineering, Faculty of Nuclear

Power Plants and Installations with a degree in Heat

Power Engineering. He began his career at the

Institute of Nuclear Physics of the Academy of Sciences

of the Kazakh SSR as an engineer of the Operation

Service of the Experimental Reactor Unit. He also held

various positions in the RoK Ministry of Energy and

Mineral Resources, the RoK Ministry of Industry and

New Technologies and the RoK Agency for Atomic

Energy. Currently Mazhit Sharipov is a Chief NFC

Officer at NAC Kazatomprom JSC.



Kazatomprom and the Nuclear Fuel Cycle ı Mazhit Sharipov

atw Vol. 66 (2021) | Issue 5 ı September



Nuclear Expertise for Germany –

Indispensable Even After

the German Nuclear Phase-out

Spotlight on Advanced Nuclear Fuels GmbH (Framatome)


For more than 60 years, Framatome’s professionals have

specialised in the design and construction of nuclear

power plants, the supply of steam generator systems,

the design and construction of components and fuel

assemblies, the integration of automation technology

and service for all types of nuclear reactors. Worldwide,

about 14,000 employees work for Framatome and its

subsidiaries, such as ANF.

The site near Hanau is a competence center for spacer

production for Framatome worldwide. ANF, with its

approximately 420 employees, is a wholly-owned

subsidiary of Framatome GmbH (Erlangen). Specialist

departments within the group of companies are

responsible for the development and design of the

fuel assemblies manufactured at ANF. The close

exchange between the divisions ensures the feedback

of experience and the continuous further development

of the products.

Framatome in Germany

Framatome in Germany with its subsidiary ANF bundle –

especially at the Erlangen, Lingen and Karlstein

sites – comprehensive engineering and manufacturing

capacities and are thus important know-how carriers

for German industry.

The company offers knowledge and experience across

the entire nuclear value chain. With its safety-oriented

technologies for several nuclear power plant types and

models (PWR, BWR, VVER, EPR), the competence

network has always made an important contribution

to the global industry.

Employees: > 3,000

Turnover: > 700 M€

Export share: > 85 %

Locations: Erlangen



Framatome in Lingen

(Advanced Nuclear Fuels GmbH)

Advanced Nuclear Fuels GmbH (ANF), based in Lingen,

manufactures boiling water reactor and pressurised

water reactor fuel assemblies for the European market.

The site also offers special products, manufacturing

technology and consulting services for fuel element

manufacturers worldwide. In addition to the

plant in Lingen, ANF also has a component production

facility in Karlstein (Main).

In order to be able to manufacture fuel rods and fuel

elements, the Lingen plant needs cladding tubes and

components such as lower and upper tie plates as well

as spacers. These metallic components are manufactured

both in Germany – at the Karlstein plant – and

in Framatome’s international manu facturing network.

At the same time, the Lingen plant supplies uranium

powder and fuel rods to sister companies abroad. This

allows a flexible response to customer requirements

and synergies in research and development can be


The Lingen fuel element plant is licensed to process up

to 650 tonnes of uranium per year in the form of fuel

elements. In addition, up to 800 tonnes of uranium per

year of conversion services may be provided. Since the

start of operation in 1979, 38,000 fuel elements with

more than 6.8 million fuel rods have left the Lingen

plant. The last fuel assemblies for the German market

were delivered in December 2020.

As a result of the German phase-out of nuclear power

generation, the site has received orders for the

reconstruction and dismantling of fuel assemblies that

have not yet been used, thus contributing to nuclear

fuel freedom in decommissioned German nuclear

power plants. Special competences in the development

and construction of manufacturing technologies form

another mainstay and ensure high manu facturing

quality and thus safety in nuclear power plants outside

Germany as well. ANF provides training and further

education for experts in radiation protection, fissile

material monitoring and other nuclear technology

personnel. This is knowledge and expertise that will still

be needed in Germany after 2022.

Site Spotlight

Nuclear Expertise for Germany – Indispensable Even After the German Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September


Stefan Möller, employee in the

production of ANF in Lingen, assembling

a 17 x 17 fuel element for a pressurized

water reactor. The fuel rods are

auto matically pushed into the

predefined locations. Such a fuel element

contains approx. 0.5 t of uranium,

which is provided by the customer.

Hermann Grüter, employee of the fuel rod production, checks the surfaces of

the fuel rods as well as for straightness. This manual test is carried out on a

granite block and concludes several upstream test steps, for leaks for example.


Transformation: a fuel element fabricator expands its portfolio

“We already dealt with the change in the market situation very actively and

consistently more than 10 years ago, especially in Germany,” explains Peter

Reimann, Managing Director of ANF. “Due to the German energy turnaround,

which heralded the end of elec tricity generation through nuclear power, the

pro duction volume for fuel elements declined notice ably. The “second” German

nuclear phase-out in 2011 has led to an approx. 50 per cent decline in the

manufacturing volume for pressurized and boiling water reactors to date,” he

explains further. “We were able to compen sate for this in part by manufacturing

special products,” he adds.

Peter Reimann,

Managing Director of ANF.

Thus, in recent years, the site has been increasingly transformed into a solution

provider for special products – for example, Gadolinium- and Chrome- doped

tablets and technology. The special com pe tences acquired over many years in

the development of technology solutions and in the construction of machines

and plants for fuel element fabrication are now being successfully marketed

and have become a secure pillar in the overall portfolio.

Current and Future Portfolio at the Framatome Site in Lingen

Development of industrial



We continuously and sustainably

develop innovations

in manu facturing, technology

and processes and create an

innovation portfolio.

Production of top technologies and

provision of services




Sale of important high-end systems

for fuel element production, individually

adapted to customer requirements.

Complete after-sales services for plants.

New: Production and maintenance of transport

containers on behalf of the Framatome.

Manufacture of fuel products




The production of fuel elements continues

to be our core business and will continue to be

the main revenue driver in the coming years.

We are flexible and build different designs on a

very high, inter nationally recognized quality level.

New: We are expanding our range with an

Eastern European design, so we follow an EU

competition recommendation.

Site Spotlight

Nuclear Expertise for Germany – Indispensable Even After the German Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September



Before welding the end plug, a spring is inserted into the fuel rod.

This ensures a stable tablet column during production,

but also during transport of the fuel elements to the customer.

Ralf Krüssel, project engineer,

is part of the team

that successfully developed APIS.

Successful examples for special mechanical engineering

Welding systems

The welding systems developed at ANF using the

resistance pressure welding process are set up and

commissioned on site. The welding technology ensures

gas-tight fuel rods – and thus contributes to the safe

use of fuel elements in reactor operation. Behind this

are 50 years of experience and constant further

development of the technology. Welding systems

from Lingen are part of Framatome’s portfolio and are

used in fuel assembly fabrication worldwide.

Testing facilities

The development of the APIS (Automatic Pellet

Inspection System) by ANF Lingen dates back to the

1980s. Since that time, research has been carried out

on the automatic measurement of pellets and the

completion of a suitable system has been advanced.

After many trials and with a higher computer capacity

required for the measurements, it was then possible

in 2007 to qualify and use the first fully automatic

pellet inspection system. With this, all pellets (100 %

inspection) are inspected for various characteristics

automatically, at high speed and with objective

criteria, evaluated and sorted out if necessary. The

APIS as part of the pellet grinding line will also be used

as best practice in Framatome’s sister plant Romans in

the future. The system ensures quality and economic

efficiency. It also reduces the strain on employees at

the workplace. In the meantime, there is already a

further development, which is currently being set up

at the Framatome site in Romans.

“We are proud of the development of our technology

division, but it can only be operated and further

developed in the long term with a functioning fuel

assembly production,” explains Lingen site’s manager

Andreas Hoff. “Only with this can special machines

tested in our own production be marketed in the

longer term,” he adds. Hoff explains: “To compensate

for the declining volumes in fuel assembly production,

we produce special products in the pellet and rod area,

which make a major contribution to the economic

operation of the plant.”

In addition to technology and special machines, the

site markets its know-how worldwide through training

and education, service, consulting and expertise. ANF

experts sit on committees and working groups in the

nuclear industry and are sought-after contacts for

international bodies such as the International Atomic

Energy Agency (IAEA) and the European Safeguards

Research and Development Association (ESARDA).

For Peter Reimann, one thing is certain:

“Framatome GmbH and Advanced Nuclear

Fuels GmbH want to continue to support

the Federal Government in achieving the

goals of maintaining nuclear com petence

and contribute to ensuring that Germany

remains internationally recognized in the

field of nuclear technology.”

Site Spotlight

Nuclear Expertise for Germany – Indispensable Even After the German Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September


Site manager Andreas Hoff at the

Lingen plant with a PWR fuel

element. In the background you

can see the underfloor storage

facility where fuel assemblies are

stored suspended before they are

transported on to the customer.


Nuclear know-how in demand worldwide

For many countries, nuclear power generation is and will remain an essential part of the national climate

strategy for the coming decades. In Germany too, expertise is still needed for nuclear dismantling, interim

and final storage, but also on issues of national and international safety.

Framatome’s experience feedback in Germany from international projects with various reactor types from

different manufacturers in its current value-added depth complements the decades of experience and

broad expertise, and makes a significant contribution to reconciling national safety requirements and the

safe further development of nuclear energy.

The competences of Framatome GmbH and Advanced Nuclear Fuels GmbH contribute significantly to these




Retention of know-how and personnel: Only participation in international projects can ensure exchange

with international partners and thus feedback into training and teaching.

Maintaining competence for activities that are still pending in Germany: Participation in international

projects ensures that nuclear know-how continues to be available in Germany – an essential prerequisite

for maintaining competence for the upcoming challenges such as dismantling, final storage and safety

research in Germany.

p Maintaining a central role in international bodies: By participating in international projects, nuclear,

safety-relevant competences are maintained and expanded. In this way, the Federal Republic of

Germany continues to secure its position as a competent partner in the field of nuclear technology in

international organizations such as the UN, IAEA, OECD, EU and in standards bodies. It can thus continue

to ensure its influence in the future so that globally binding safety standards are met and nuclear

technology is used for the benefit of all.



Information about developments: Through its involvement in global value chains, the Federal Republic

can gain early access to information and knowledge about developments, projects, planning and

regulations. Without Germany’s active participation in the international nuclear industry, this

knowledge would not be available.

Fuel optimization: The development of fuel elements with high utilization as well as the conversion and

recovery of raw materials from unirradiated products will minimize the amount of used fuel elements

in Germany and worldwide.

Site Spotlight

Nuclear Expertise for Germany – Indispensable Even After the German Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September




Urenco-Group approx. 1600

Urenco Deutschland GmbH approx. 300


Urenco-Group (2020) > 1700 m€

Urenco Deutschland GmbH (2020) > 400 m€

Nuclear Competencies in Germany –

a Legitimate Case Also After the Nuclear


Spotlight on Urenco Deutschland GmbH

Urenco – enrichment services and

fuel cycle products.

For more than 50 years, Urenco has offered its global

customers safe, cost-effective and reliable uranium

enrichment services based on centrifuge technology

developed in-house. It is the only supplier in the world

to operate enrichment facilities in several countries

simultaneously: the Netherlands (Almelo, since

1973), the United Kingdom (Capenhurst, since 1973),

Germany (since 1985) and the United States (Eunice,

NM, since 2010). Thus, as a supplier to 50 utilities in

21 countries, Urenco contributes significantly to a safe

and low-carbon electricity supply in many countries

around the world.

Centrifuge technology is also used in the Urenco

Group to separate other isotopes. These isotopes are

used, for example, in research or medicine. Last year,

operations began at the Tails Management Facility

(TMF) in Capenhurst. This enables responsible and

resource-conscious handling of depleted uranium.

In addition, Urenco is involved in the development of

U-Battery, an advanced modular reactor.

Site Spotlight

Nuclear Competencies in Germany – a Legitimate Case Also After the Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September


Tails yard


Urenco Deutschland GmbH – Developments at the site

At the end of the 1970s, the course was set for the location

of Germany‘s first and only uranium enrichment

plant at the Gronau site. The seismically inactive area and

the proximity to the already existing Dutch site were

some of the reasons for the location. The German

production team first gained experience in the Netherlands

before the plant in Gronau in the Münsterland area

went into operation in August 1985 after a successful

licensing and construction process. Since then, Urenco

Germany has produced about 67,000 tones of enriched


The nuclear fuel produced from this work has generated

and continues to generate economically about

5.8 trillion kWh of electricity in nuclear reactors, about

10 times the electricity consumption of the whole of

Germany for the year 2019.

A lot happened since the late 1970s, when the site was

purchased, and August 1985, when the first cascades

went into operation. An important development step

happened on Valentine‘s Day 2005, when permission

was granted to expand the plant. At that time, the

responsible authorities in Düsseldorf and Berlin were

both led by a red-green government. The construction

of the uranium separation plant 2, or UTA-2 for short,

then took place. Finally, in autumn 2011, the last

cascades were put into operation and the total

capacity of the plant was increased towards the

approved 4,500 t of separative work per year. As the

last part of the expansion permit, the commissioning

of the structurally complete uranium oxide storage

facility is pending.

For the Federal Republic of Germany,

Walter Scheel and Hans Leussink signed as

responsible Federal Minister/Vice Chancellor

At the beginning of 2017, Urenco‘s Central Technology

Group (CTG) moved from Bad Bentheim (Lower

Saxony) to the Gronau site. Since then, the jointly used

76 ha site has been called the “Gronau Technology

Centre”. This name is all the more appropriate since

“Urenco Technology & Development” (UTD) evolved

from CTG in 2021. UTD consists of highly qualified

employees from all Urenco countries who work and

provide services for the entire group from its main site

in Gronau.

Urenco Deutschland GmbH –

Treaty commitments and oversight

In 1970, the signing of the Treaty of Almelo (NL) marked

the beginning of a hitherto unique international

cooperation in the field of uranium enrichment. Great

Britain, the Netherlands and Germany agreed to jointly

develop centrifuge technology and to use the nuclear

fuel produced exclusively for the peaceful use of nuclear

energy. Nonproliferation has been an important topic

from the very start. With this state anchoring, the

success story of Urenco began.

Over time, this international framework has been

extended. The Washington (1992) and Cardiff (2006)

treaties allow the sharing of technology with French

companies and the construction of a new plant in the

USA. In addition to the multi-state supervision via the

so-called Joint Committee, there are regular controls

by international institutions such as the International

Atomic Energy Agency (IAEA) or the European Atomic

Energy Community (Euratom). There other links with

the IAEA too. For years, Urenco Deutschland GmbH

has supported the IAEA in the training of future

inspectors; and in 2020, the sponsorship of the Marie

Sklodowska-Curie Fellowship Programme by Urenco

was announced by CEO Boris Schucht during an

appointment with IAEA Director General Rafael Grossi.

In addition, ETC Germany, as a subsidiary of Urenco, is

engaged on behalf of the German government with

specialist knowledge and unique expertise in the field

of nuclear nonproliferation and supports the IAEA.

Site Spotlight

Nuclear Competencies in Germany – a Legitimate Case Also After the Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September



The enrichment process

Cylinder handling UTA-2

Central control room

To initiate and sustain a controlled chain reaction in

natural water, uranium fuel must have a concentration

of U-235 greater than 3 %. Naturally occurring uranium

has a concentration of 0.711 % U-235. The actual

principle of enrichment is simple. By means of rapidly

rotating rotors inside rigid recipients, the difference in

mass between different uranium isotopes can be used

to initiate a separation process and increase the

concentration from 0.711 to about 3-5% U-235 for the

use of nuclear energy for power supply. What makes

this process so challenging and special can be described

as follows:

The cylinders

Roughly speaking, there are two standardised pressure

vessel types that are used to transport the uranium

with its accompanying fluorine (uranium hexafluoride

or UF 6 ). The 30B cylinders are about 2.20 metres long

and hold about 2.2 tonnes of UF6. In total, a cylinder

weighs 2.85 t. The larger 48Y cylinders with a length of

about 3.8 metres weigh about 15 t with UF 6 . As a rule,

the natural uranium and the depleted uranium are

delivered or transported in the 48Y cylinders. In

addition to road transport, the company‘s own railway

siding can also be used for this purpose. The smaller

30B containers are used to transport the final product

according to customer requirements. The manufacturers

of the containers and the production itself

are highly qualified. The cylinders are periodically

inspected and subjected to several tests in accordance

with hazardous goods legislation. These include a

28 bar pressure test, a drop test on an unyielding steel

plate and a fire test (48Y and 30B containers). In

addition, the tanks are made of thick-walled steel (13

or 16 mm) and are visually inspected every quarter in

the storage yard. In the almost four decades of

Urenco‘s operation, there has not been a single

incident or even sign of leakage from a cylinder.

When transporting both the 30B and 48Y cylinders,

protective packaging is also used to protect the

material and the cylinder against, for example, a

theoretical fully contained fire.

The process

For the real procedural process of uranium enrichment,

solid UF 6 (feed) is delivered by truck or rail. Both the

cylinders and the equipment provided are inspected

for possible external contamination and damage as

well as for their suitability. To check the uranium

content, the containers are transported to the separation

plant by a special transport vehicle, where they

are weighed and sampled.

In the plant built until 1998 (UTA-1), the UF6 is fed from

the transport containers by means of a heating station.

In this station, the feed containers are heated to

80 to 100 °C by electrically heated warm air, whereby

their contents liquefy completely. The vapour pressure

created above the liquid phase is fed to the centrifuges

after a multi-stage pressure reduction. After enrichment

in the centrifuges, the UF 6 is fed into deep- frozen

collection containers (desublimors). Here it is frozen

out of the gas phase at -70 °C (desublimated). Water is

used as a coolant for tails and air for product. The filled

desublimors are heated and the evaporating UF 6 flows

in gaseous form through pipes into the transport

cylinders, where it solidifies again through cooling.

In all plant sections built since 1998, feed is supplied

directly from the solid UF 6 phase under athmosphere

pressure. UF 6 pumps are used, which have a much

smaller UF 6 inventory and lower energy consumption

compared to the process described above. Also, in

contrast to the desublimors, much smaller quantities

of refrigerant are required. Product and tails are

desublimated directly with low-pressure pumps into

deep-frozen UF6 transport and storage containers.

There are physical limits to desublimation in a single

centrifuge. No further enrichment or depletion takes

place beyond a certain stage. In the centrifuge process,

the solution is to interconnect several centrifuges

to form so-called cascades. The UF 6 gas is separated

in cascaded centrifuges into an enriched stream

( product) and a depleted stream (tails) (see figure). In

the product transfer system in the technical infrastructure

building, product material of different U-235

concentrations is mixed in order to set the exact

concentration required by the customer for each

container. In the process, the UF 6 is homogenised

(mixed) by reheating and liquefaction. Finally, samples

are taken to determine the degree of enrichment,

before the containers filled with tails or product are

transported to the respective warehouses.

Site Spotlight

Nuclear Competencies in Germany – a Legitimate Case Also After the Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September


Dr. Joachim Ohnemus

Urenco – Outlook for the future.


Managing Director Dr Joachim Ohnemus sees Urenco

Germany well positioned for the future: „We benefit

from our German mentality. People in the group know

about German virtues. Guests, for example, are often

amazed at the condition of our first plant, which is

already 36 years old. The great effort when it comes

to maintenance measures, ageing management,

redundant design and normal cleaning services is

simply visible in the plant and on its components. In addition,

the installed centrifuges are proving to be very

durable. The cascades from the 1980s and 1990s are

still in operation and generating output. More over, we

are the only European plant to have installed the most

modern centrifuges in our new plant, UTA-2. Only our

US colleagues also use the TC-21. This makes us very

proud, of course, and ensures a balanced plant structure

with tried-and-tested technology that has proven its

efficiency for decades, and with the world‘s most

modern centrifuges and corresponding infrastructure

that has virtually ushered in a new generation.

Nevertheless, we must not rest on our laurels. As the

Urenco Group, we have launched various diversifi cation

projects in order to be able to respond to changing

customer requirements. At our site, Urenco Technology

& Development (UTD) is a sign of our further internationalisation

and the efficiency improvements of the

entire Urenco Group.

I am proud to have been able to follow the path of

Urenco Deutschland as Managing Director for 23 years.

At the end of my career, I am now looking forward to

the 2021 parliamentary elections before I hand over

the baton to my successor, Dr Jörg Harren. Not only can

he look forward to a healthy company in terms of

numbers, but above all to a very committed, wellcoordinated

and highly qualified workforce.“

Sustainability and Net Zero

Sustainability is integral to

everything we do and in 2021

we have refreshed our sustain ability strategy, which is now focused

on three building blocks: environmental impact; social impact and

governance and ethics.

This followed a materiality assessment, gathering the views of key

stakeholder groups through interviews with industry and sustainability

experts, a customer survey, and an employee survey and workshops.

All stakeholders were asked to identify priorities for Urenco from a

comprehensive list of sustainability topics. We took this feedback and

considered the key role that Urenco plays in facilitating the low carbon

energy that society needs; how we conduct our day-to-day activities

with minimal impact to the environment and the communities in which

we operate; and the strategic goals for our long term success.

The resulting refreshed sustainability strategy demonstrates how

Urenco contributes to a net zero world and the United Nations

Sustainable Development Goals (SDGs), and aligns with established

environmental, social and governance (ESG) frameworks.

We are currently working on defining new key performance indicators

and our roadmap to net zero by or in advance of 2040 as part of our

commitment to The Climate Pledge. The roadmap will focus on the

areas of ‘eliminate and reduce’, ‘substitute’ and ‘offset’ and this will be

finalised and communicated later this year.


U-Battery, a micro-modular reactor development programme

involving Urenco, progressed through to the next stage of the

UK Department of Business, Energy and Industrial Strategy’s

(BEIS) Advanced Modular Reactor (AMR) competition last year.

This saw a further £10m contribution from the UK Government

to conduct design and development work to bring the new

nuclear technology closer to market.

It follows the successful completion of a feasibility study that

made the business, economic and technical case for the

deployment of U-Battery in the UK and in Canada, where it

would be deployed in industrial applications, mining sites and

remote locations and have a positive effect on decarbonisation

and climate change efforts. It is also a highly versatile technology

that can be used for other beneficial purposes, such as the

production of hydrogen through the copper chlorine process.

U-Battery received an additional £1.1m of funding from BEIS to

design and build the two main vessels (the reactor and intermediate

heat exchanger) and the connecting duct. During the

next phases of the programme, U-Battery will be working to form

new partnerships for the longer term development of the AMR.

Site Spotlight

Nuclear Competencies in Germany – a Legitimate Case Also After the Nuclear Phase-out

atw Vol. 66 (2021) | Issue 5 ı September



SSiC Nuclear Waste Canisters:

Stability Considerations During Static

and Dynamic Impact

Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

Introduction High-level radioactive waste (HLW) is mainly a by-product of technical nuclear reactions. It has the

highest radioactivity and longest decay time (millions of years with significant radiation). Most HLW (more than 90 %)

comes from spent nuclear fuel. The deep geological disposal concept is considered without alternatives worldwide.

This concept includes the multibarrier

concept, which contains three

main elements:

p Canisters: HLW is sealed safely in

special long-term safe canisters.

p Engineering barrier: Canisters are

embedded into an engineered

sealing environment (e.g. bentonite)

inside the host rock.

p Geological barrier: Embedded

canisters are safely buried underground

protected by geological


This concept should work for

extremely long time (> 1 Mio. years),

so that any critical contact between

waste and biosphere is avoided.

Two concepts for canisters exist:

corrosion resistant ones and corrosion

allowed ones. Corrosion resistance

considers attack from water, acid,

alkali, salt, radiation, bacteria etc. for

a very long time (e.g. resistance

> 100,000 years). Allowed corrosion

means limited corrosion is accepted

and safety is guaranteed only for a

certain restricted time span (e.g.

about 1,000 years). The central point

is to choose most corrosion resistant

material while meeting also other

criteria. Different countries have

developed different philosophies in

terms of canister design. So far, the

following materials for canisters and

over-packs, respectively, are under

consideration: stainless steel/carbon

steel, nickel alloy, cast iron, pure

copper or copper coating, special

concretes, aluminum, SiC, ZrC,

ceramic coatings.

All the above-mentioned materials

and corresponding canister concepts

have their pros and cons. For nearly all

of them it is critical to proof extreme

long lifetime. In terms of resistance

and lifetime SiC and SSiC especially,

show some remarkable advantages.

Already Onofrei et al. [1] studied

the leaching characteristics of ceramic

canisters. Haslam et al. [2] evaluated

corrosion resistance of ceramic

coatings thermally sprayed on waste

containers in simulated ground water

of 90 °C. Donald et al. [3] estimated

the lifetime of SiC and ZrC coatings

for nuclear fuel in TRISO and TRIZO

concept for direct geological disposal.

Kerber and Knorr [4] proposed a

new concept by SSiC (solid-state

pressure-less sintered silicon carbide)

encapsulation of HLW. This concept

has drawn attention due to the

excellent corrosion resistance, low

permeability and high mechanical

strength of SSiC (see Table 1).

On the other side, SSiC is a brittle

material. Therefore, it is necessary to

consider the stability and potential

fracturing of SSiC canisters under

static and dynamic loading scenarios.

This paper considers this problem via

numerical simulations concentrating

Inert gas, reducing atmosphere Stable up to 2,320 °C

Oxidizing atmosphere


Water vapor

Acids, diluted and concentrated

H 3 PO 4


Potassium hydroxide solution

Molten sodium and


on tensile failure (mode-I crack

propagation in terms of fracture

mechanics). Unprotected and protected

(coated, covered) canisters are

investigated. It is not the aim of

this study to deliver comprehensive

simulations for final canister design,

but to provide the order of magnitude

of potentially induced impact stresses

for different loading scenarios and to

document, that proper cover ( coating)

of SSiC canisters can avoid any kind of

mechanical damage during transport,

installation and final storage.

Lab testing and numerical

calibration of SSiC

Special lab tests like illustrated in

Figure 1 were conducted to determine

the tensile strength of the SSiC.

Resistant up to 1.650 °C, above 1,000 °C

formation of protective layer of silica

Stable < 1,430 °C, > 1,430 °C appreciable attack

Stable < 1,150 °C, > 1,150 °C some reaction

Resistant at RT and elevated temperatures

Some attack

Appreciable attack

Appreciable attack

Appreciable attack > 500 °C

Fused sodium carbonate Appreciable attack > 900 °C

Sintered Density > 3.10 g/cm 3

Young’s Modulus

| Tab. 1.

Parameter of SSiC.

400 GPa

Poisson Ratio 0.16

Vickers Hardness HV200

25.7 GPa

Fracture Toughness (indentation with 10 N load) 4.9 MPa m 1/2

Thermal Conductivity

Strength (4-point-flexural test)

120 W/mK

400 MPa

Coefficient of Linear Thermal Expansion at RT 3.3 x 10 -6 K -1

Porosity 1 % – 2 %

Specific Electrical Resistance (depending on impurity level SiC)

Maximal Pore Size

Maximal Crystal Size

10 2 – 10 4 Ωcm

20 – 50 µm

35 µm

Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

atw Vol. 66 (2021) | Issue 5 ı September

Bulk modulus (GPa) 200

| Fig. 1.

Numerical simulation and lab tests of small hollow SSiC cylinders; Numerical model duplicating the lab

tests with indication of tensile failure development at peak pressure; Load-displacement curves of lab

tests and numerical simulation results assuming tensile strength of 150 and 200 MPa, respectively.

This type of test was chosen due to the

following reasons: (a) the extremely

high strength of the material would

make classical tensile tests complicated

and (2) this type of tests

duplicates very well the real canister

situation as hollow cylinder. The

tested cylinders are 5 cm in length and

have outer and inner radius of 2.5 cm

and 2.0 cm, respectively. The small

hollow SSiC cylinders were compressed

between 2 loading platens

until tensile failure initiated at the

inner cylinder wall leads to brittle

failure. In total five lab tests were

conducted, results are presented in

Figure 1. For a hollow cylinder under

compressive line loading the following

analytical solution developed by

Timoshenko exist for the failure load:



ρ – ratio of inner to outer radius

of cylinder

R – outer radius of cylinder

P – tensile failure load

σ θ – tensile strength

θ – angle.

After conducting the lab tests, equivalent

numerical simulations were

performed (see Figure 1). A modified

elasto-plastic Mohr-Coulomb failure

criterion with tension-cut-off and

strain- softening was applied. To

duplicate the extreme brittle behavior,

after reaching the tensile strength,

softening starts immediately and

tensile strength is set to zero. The

cohesion was deduced from a test

with similar material (SiC-N) and set

to 4 GPa [5]. Tab. 2 shows the used

Shear modulus (GPa) 180

Friction angle (°) 40

Tensile strength (MPa) 150 / 200

Density (kg/m 3 ) 3100

Cohesion (GPa) 4

Dilation (°) 0

Elastic modulus (GPa) 415

Poison’s ratio µ 0.15

| Tab. 2.

Numerical model parameters for SSiC.

| Fig. 2.

Analytical and numerical simulation results for failure load P with varied

radius ratio ρ assuming tensile strength of 150 MPa.

model parameters. The distinct

element code 3DEC [6] was used for

the simulations.

According to Figure 1, the tensile

strength of SSiC is somewhere

between 150 MPa and 200 MPa. For

safety reasons, the tensile strength of

SSiC is set to 150 MPa in all further

calculations. According to Eq. (1) the

failure line load P is determined by

tensile strength σ θ , outer radius R,

as well as radius ratio ρ (ρ = r/R).

Figure 2 compares numerical and

analytical results for failure load P for

different radius ratios and proves that

numerical simulations deliver reliable



Simulation strategy

to consider static and

dynamic loading

Different loading scenarios are considered

under conservative assumptions.

Dynamic loading (impact) is

considered for scenarios during transport

and installation of the canisters.

Static loading via in-situ rock stresses

is considered after final placement of

the canister. Dynamic loading scenarios

comprise two cases: (a) free fall of

a canister and (b) rockfall from

the roof on the canister. In both cases

the considered maximum drop

height is 2 m. In case of static loading

the maximum disposal depth is

Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

atw Vol. 66 (2021) | Issue 5 ı September



Bulk modulus


Shear modulus



(kg·m -3 )

Elastic modulus


1200 meters below surface with

different anisotropic stress ratios

(minimum to maximum principal

stresses) up to 1:3. SSiC canister and

foundation are modelled as elastic

material. The falling rock blocks are

simulated either as elastic material or

as assembly of distinct blocks with

calibrated elasto-plastic parameters,

which allows to consider the rock

disintegration during the impact.

Damping was not applied for the

dynamic simulations because data are

not available, but viscous boundary

conditions were applied to avoid

unrealistic reflections at the lower

bottom of the ground. This makes the

simulations once again conservative.

The interface stiffnesses at the contact

between the colliding parts (e.g.

between canister and rock block or

ground) are adjusted in such a way,

that impact induced stresses reach

maximum values (corresponding lab

data are not available). So far not

explicitly otherwise mentioned the

model parameters given in Table 3 are


µ jkn

(GPa·m -1 )


(GPa·m -1 )

Rock & Foundation 40 29 2500 70 0.21 100 100

Buffer 1 0.5 2000 1.35 0.27 100 100

SSiC 200 180 3100 415 0.15 100 100

Clay-stone 40 18 2500 47 0.30 100 100



TPa·m -1


| Tab. 3.

Matrix and interface contact parameters.


TPa·m -1














jkn = jks = 440 TPa·m -1 for dynamic loading to avoid unrealistic penetration

| Fig. 3.

Left: Cross section of cylindrical canisters (see also Table 4); middle: Model set-up for canister completely

imbedded inside the host rock incl. buffer; right: Impact constellations of canisters after free fall.

Canister a/mm b/mm c/mm d/mm e/mm f/mm

HTR (5 pebbles) 62 305 92 335 15 15

CANDU 102 510 142 550 20 20

PWR/BWR 400 4930 470 5000 35 35

Vitrified waste 450 1350 500 1400 25 25

| Tab. 4.

Dimensions of canisters (see also Figure 3).

| Fig. 4.

Maximum tensile stress inside unprotected canister for different inclination

angles of VW (up) and HTR (middle) canister (see Table 5).







Four different canister types are

considered as given by Figure 3 (left)

and Table 4. The considered waste

canisters are hollow cylinders sealed

at one, respectively the two ends using

the technique of Rapid Sinter Bonding

(RSB) as proposed by Knorr and

Kerber [7].

Static loading scenarios

This loading case considers anisotropic

earth pressure on completely in

a rock mass embedded VW and HTR

canisters (Figure 3 (middle)). Table 5

lists all the considered earth pressure

constellations in terms of principal

stresses (X and Y (both horizontal)

and Z (vertical): 1:1:1, 2:1:1, 3:1:1,

2:2:1, 3:2:1, 3:3:1. These constellations

cover all typical stress states

existing in potential host rocks. The

considered maximum principal stress

ratio is 3:1. The angle between canister

axis and Z-axis is set to 0 °, 30 °,

60 ° and 90 °, respectively. Figure 4

documents the maximum induced

tensile stresses inside the SSiC canisters.

The considered depth is 1200 m,

and the vertical earth pressure will

be about 30 MPa. Overall, in any

case the maximum tensile stress in

the unprotected canister does not

exceed 50 MPa which is significantly

below the tensile strength of SSiC,

which is 150 MPa. Maximum tensile

stress is mainly distributed around

the two lids of the canister as shown

in Figure 5. The average stress in

the VW canister is bigger than that

in the HTR canister. The thickness of

the canister is a controlling factor.

For the VW canister, the thickness/

height ratio is 1/56, while the thickness/height

ratio for the HTR canister

is 1/22.

Exemplary, for the HTR canister

some selected simulations with a

buffer sealing (200 mm thick) were

performed. As Figure 6 documents,

such a clay (bentonite) buffer can

significantly reduce maximum tensile


Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

atw Vol. 66 (2021) | Issue 5 ı September

| Fig. 5.

Maximum tensile stress [kPa] distribution for unprotected canister,

left: VW canister, rock stresses X: 30 MPa, Y: 10 MPa, Z: 10 MPa, inclination

angle 0 °; right: HTR canister, rock stresses X: 30 MP, Y: 30 MPa, Z:10 MPa,

inclination angle 30 °.

Loading case X/MPa Y/MPa Z/MPa (X/Z)

Case 1 10 10 10 1

Case 2 20 10 10 2

Case 3 30 10 10 3

Case 4 20 20 10 2

Case 5 30 20 10 3

Case 6 30 30 10 3

| Tab. 5.

Primary stresses (see Figures 5 and 6).

| Fig. 6.

Maximum tensile stress of unprotected HTR canister and buffer-sealed

canister for canister inclination angle of 0 ° and 30 ° (buffer thickness

200 mm).


| Fig. 8.

Top: maximum tensile stress at impact [kPa];

Bottom: canister with deformed cover during the collision.

| Fig. 7.

Maximum tensile stress of unprotected canisters versus drop height.

Dynamic loading scenarios

Free fall of canister

For impact, drop height and canister

positions are the controlling factors.

The considered drop heights (distance

from the lowest point of the canister to

the foundation) are 0.5 m, 1.0 m,

1.5 m, and 2.0 m, respectively. The

canister positions during impact

(0°, 30°, 60°, 90°) are illustrated in

Figure 3 (right). Figure 7 shows the

maximum induced tensile stresses in

the different canisters for different

drop height and documents, that peak

tensile stresses can very locally reach

values considerably higher than the

material strength. Therefore, an

additional simulation was performed

assuming a protective cover (layer)

around the SSiC canister. Simulation

of a VW canister (drop height 1 m,

inclination angle 0°) with soft cover

(50 mm thick) confirms significant

reduction of maximum tensile stress

| Fig. 9.

Top: Considered constellations of dropping rock pieces at the time of

impact; Bottom: Induced maximum tensile stresses in VW canister for

different simulation cases.

Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

atw Vol. 66 (2021) | Issue 5 ı September


at the inner boundary of the canister

from 1118 MPa (without cover) to

147 MPa (with cover) (Figure 8).

Free fall of rock blocks

First, preliminary pure elastic simulations

using the VW canister were

performed. Small rock pieces were

considered with weights of 0.5, 1.0

and 2.0 kg, respectively. Drop height

is 2.0 m (distance from the lowest

rock piece point to the highest line

of horizontally disposed canister).

Simulation cases 1 to 4 generate

dynamic line loads, case 5 to 7 lead to

point loads (see Figure 9 (up)).

Figure 9 (down) shows the maximum

induced tensile stresses in a VW canister

during impact for seven loading

cases. Similar results were obtained

for the other canister types. It becomes

obvious from Figure 9 (down), that

(a) even small rock pieces produce

tensile stresses close to the strength of

the SSiC material or even larger

ones and (b) point loading loads to

significant higher values compared to

line loading.

Rock weight


D = 20 mm

E = 800 MPa

Such a pure elastic consideration is

too conservative, especially because

the limited strength of the rock pieces

is not taken into account. It has to be

expected that extreme high local

stresses during impact at point or line

contacts lead du massive fracturing of

the rock pieces, so that stresses above

the rock strength will not be reached.

To investigate this phenomenon the

rock pieces were set-up by numerous

distinct elements, so that fracturing

and disintegration can take place if

strength of the rock is exceeded.

Calibration was performed using

typical rock parameters. Figure 10

shows results from a calibration

process for claystone. Figure 10

reveals, that vertical splitting (tensile

cracking) is dominating like typically

observed during uniaxial lab tests.

D = 20 mm

E = 80 MPa

8 5 mm / 130 MPa 12 mm / 70 MPa

D = 80 mm

E = 100 MPa

40 17 mm / 70 MPa

| Tab. 6.

Maximum penetration depth and maximum induced tensile stresses inside a CANDU canister with

soft cover of thickness D and Young’s modulus E during pure elastic collision with claystone rock piece

(drop height 2 m, loading case 1 according to Fig. 16).

| Fig. 10.

DEM-model for claystone: up: stress-strain-curve from

uniaxial compression test, down: DEM model at the

time of failure indication cracking and disintegration.

| Fig. 11.

Top: claystone rock piece in point contact with CANDU canister;

Bottom: sequence of rock splitting process during impact

(drop height 2 m, weight 1 kg).

| Fig. 12.

Top: Maximum tensile stress inside the CANDU canister versus collision

time for rock piece elements with edge length of 4 mm, 6 mm, or 10 mm;

point contact according to Figure 9 (up) (drop height 2 m, weight 1 kg);

Bottom: Maximum tensile stress inside the CANDU canister during impact

with claystone rock pieces for loading case 1 (see Figure 9 (up)) versus

volume ratio (volume of distinct elements to volume of rock piece)

Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber



Our mission and your passion

We are true believers in the necessity of sustainable green energy and we believe

that there is an inextricable close tie between the abundance of accessible energy

in the world, and the well being of our civilization.

As a growth company we are looking for two nuclear engineers or physicists who

have that same passion alongside several years of experience in computer

modeling, neutronics, CFD, etc. We assume that you have experience with

Serpent, OpenMC, MCNP, OpenFoam or similar and that you have a good

understanding of molten salt reactors and how they are different from LWRs.

Who are you?

Curiosity is part of our culture and how we train every day as a team to become

world champions of our mission. We are very curious of who you are and what

purpose you have in life. What is your story and what are your dreams? As team

players we depend on each other whether big or small projects and delivery.

Hence, we make a huge effort to keep our promises and deadlines because it

affects all of us. Our work pace can be intense at times due to our high ambitions,

and errors can be expensive. However, if you like to be challenged Copenhagen

Atomics might be the right place to work for you.

Professionally we hope you have experience with 3D CAD drawings and meshing

of such files. Preferably you also have knowledge in material properties and we

are keen that you are skillful with Linux and programming experience with e.g.

C++ or Python..

You can apply for this position at jobs@copenhagenatomics.com Please send

your CV along with 10 - 20 lines about yourself and your experience with nuclear

computer modeling and why you would like to work with MSRs.

About Copenhagen Atomics

Based in Copenhagen we’re an international growth team of 35 engineers,

technicians and designers who are in the process of developing nuclear power

plants to be manufactured on assembly lines in the future. We expect many new

colleagues to join our company within the next 5 years as we expand our breath

and capabilities even further.

Copenhagen Atomics ApS, Maskinvej 5, 2860 Søborg, Denmark | copenhagenatomics.com

atw Vol. 66 (2021) | Issue 5 ı September



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Exemplary, Figure 11 illustrates

the collision process for point load

impact. Figure 12 (up) shows, that

the size of the distinct elements,

which control the fracturing process

in detail, is important to obtain

reliable stress values during the

impact process. The smaller the

elements, the more potential fracture

paths. However, it becomes also

visible, that below a certain threshold

the stresses will not any more

decrease. Compared with the pure

elastic modelling a significant reduction

in induced tensile stresses by a

factor of about 10 is observed. In

additional model runs also larger rock

pieces up to a weight of 512 kg were

considered (see Figure 12 (down)). It

again becomes obvious, that distinct

element resolution has significant

influence on modelling results. To get

reliable results for larger rock pieces

at least at the contact area higher

resolution is necessary. However, one

has also to consider that enhanced

resolution leads to a progressive nonlinear

increase in simulation time.

The effect of a soft cover was also

investigated using the pure elastic

approach. Table 6 shows simulation

results in terms of maximum penetration

depth and maximum induced

tensile stress. It clearly shows that a

soft cover can reduce tensile stresses

considerably, so that even for the

extreme conservative case of pure

elastic interaction, the induced tensile

stresses can be brought below the

strength of the material, which is

about 150 MPa.

Discussion and Conclusions

SSiC has excellent properties in terms

of long lifetime, high strength, low

porosity and excellent resistance

against radiation, high temperatures

and aggressive fluids. In that respect it

is superior to other materials under

consideration for nuclear waste

canisters. As documented, static earth

pressure even in case of high anisotropy

and unfavorable orientation of

the canister in relation to the principal

stresses will not reach the high failure

strength of SSiC canisters for considered

depths up to about 1200 m.

However, the very stiff and brittle

behavior of SSiC needs some more

detailed consideration in case of

dynamic impacts. Such worst case

loading scenarios like rockfall or free

fall of a canister can be investigated

Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

atw Vol. 66 (2021) | Issue 5 ı September

via field tests (large scale drop tests)

and numerical simulations. Under

pure elastic conditions and extreme

loading constellations (point and

line loads) as well as conservative

initial and boundary conditions (stiff

foundation, no damping, no protective

cover etc.) the dynamically

induced tensile stresses inside SSiC

canisters can locally and temporarily

reach – independent on canister type –

maximum tensile stresses beyond the

static tensile strength of SSiC. Even if

we consider that dynamic strength is

somewhat higher than the static one,

several constellations might give rise

of concern.

One should also take into account,

that reaching the failure envelope in

pure elastic simulations just indicate,

that damage is very likely, however,

nothing can be said about extent

and type of damage. Therefore, a

numerical simulation based safety

case should follow two directions: (a)

consideration of an additional cover

to absorb energy during potential

dynamic impact and (b) more realistic

modeling (considering of energy

absorption during collision, fracture

propagation, damping etc.). This

paper provides first hints and results

how these tasks can be handled. The

simulations with soft cover indicate

that a cover of about 10 cm with

stiffness in the order of about 100 MPa

would be able to reduce the dynamically

induced tensile stresses so that

any failure can be avoided.

The presented dynamic simulations

are only a very first step toward a

comprehensive numerical safety case.

The aim was to show, that the most

critical issue of SSiC – the stiff and

brittle behavior – can be managed.

More realistic numerical simulations

should consider the following aspects:

p Incorporation of realistic damping

p Replacement of the elastic models

for all components by calibrated

elastic-plastic models incl. damage


p More profound specification of

load scenarios

p Consideration of dynamic material


In summary, the conclusion can be

drawn, that SSiC is a suitable canister

material if a certain soft cover is used

during transport and emplacement

just in case that unexpected dynamic

collisions (rockfall of free fall of

canister) occur.


The conduction of the lab experiments

by Dr. Thomas Frühwirt (TU

Berg akademie Freiberg) is highly

acknowledged. The authors would

like to express their special thanks to

the China Scholarship Council (CSC)

for financially supporting the first

author’s PhD study in Germany.


[1] Onofrei, M., Raine, D.K., Brown, L. & Stanchell, F., (1985).

Leaching studies of non-metallic materials for nuclear fuel

immobilisation containers, Proc. Mat. Res. Soc. Symp.,

Materials Research Society., 44: 395-404

[2] Haslam, J.J., Farmer, J.C., Hopper, R.W., Wilfinger, K.R., (2005).

Ceramic coatings for a corrosion- resistant nuclear waste

container evaluated in simulated ground water at 90 °C,

Metallurgical and Materials Transactions., A (36): 1085-1095

[3] Donald W. M., Wen Wua., Francesco, V., (2012). Performance

of PyC, SiC, ZrC coatings in the geologic repository, Nuclear

Engineering and Design., 251: 102-110

[4] Kerber, A. and Knorr, J., (2013). SiC encapsulation of high-level

waste for long-term immobilization, atw 58. Jg Heft 1,

January: 8-13

[5] Lee, M.Y., Brannon, R.M., Bronowski, D.R., (2004). Uniaxial and

triaxial compression tests of silicon carbide ceramics under

quasi-static loading condition, Tech. Rep. SAND2004-6005,

Sandia National Laboratory

[6] Itasca (2020): 3DEC Manuals, Itasca Consulting Group,

Minneapolis, Minnesota, USA

[7] SiCeram (2018): Deutsche Patentanmeldung 10 2018 114

463.6 “Verfahren zum Verbinden von Bauteilen aus SSiC”,

GmbH, Jena, Germany


Yanan Zhao

TU Bergakademie


Geotechnical Institute,

Freiberg, Germany

Dr. Yanan Zhao got a master degree in Geotechnical

Engineering from Northwest A&F University in China in

2015, and a PhD degree in Geotechnical Engineering

from TU Bergakademie Freiberg in 2021. Now he works

as post PhD at Powerchina Zhongnan Engineering

Corporation Limited, Changsha, Hunan Province, China.

Prof Dr Heinz


TU Bergakademie


Geotechnical Institute,

Freiberg, Germany



Prof. Dr. habil. Heinz Konietzky has studied Geotechnical

Engineering. For more than 15 years he has

worked in the private industry worldwide as project

engineer and consultant mainly for civil engineering

projects and for radioactive waste disposal. Since 2006

he works as university professor and director of the

Geotechnical Institute at TU Bergakademie Freiberg.

Prof Dr Jürgen Knorr


Nuclear Power

Engineering, Dresden,




Since 1992 Jürgen Knorr is Professor for Nuclear

Engineering at Dresden University of Technology

(Emeritus since 2006). He graduated in physics and

prepared his PhD in nuclear technologies. From 1975

to 1992 he was responsible for the design, construction

and operation of the AKR training reactor (from

the German Ausbildungskernreaktor) in Dresden.

Between 1993 and 2000 Juergen was President of

the German Nuclear Society and Board Member of

the European Nuclear Society. The cooperation

with SiCeram GmbH for the application of high-tech

ceramics in nuclear sector startet in 2003.

Dr Albert Kerber

Managing director and

co-owner SiCeram GmbH,

Jena, Germany


Since 1998 Albert Kerber is the co-owner and

managing director of the company SiCeram GmbH

in Jena, Germany, with the emphasis on high performance

ceramics. After studying chemical engineering,

he gained his doctorate at the Technical University

Karlsruhe. The cooperation with Prof. Knorr started in

the year 2003 and focusses on the application of high

tech ceramic materials in the nuclear sector, especially

for innovative solutions in the field of nuclear waste



Decommissioning and Waste Management

SSiC Nuclear Waste Canisters: Stability Considerations During Static and Dynamic Impact ı Yanan Zhao, Heinz Konietzky, Juergen Knorr and Albert Kerber

atw Vol. 66 (2021) | Issue 5 ı September



Improving Henry-Fauske Critical Flow

Model in SPACE Code and Analysis of


BumSoo Youn

Introduction The SPACE code offers several options for critical flow model. One of the option is Henry/Fauske –

Moody model. When using this model, Henry-Fauske critical flow model is used for single phase liquid and Moody

model is used for 2-phase flow. For Henry-Fauske model, SPACE code assumes non-equilibrium(NE) factor of 0.14.

In previous OPR1000 SBLOCA analysis methodology based on RELAP5 code, non-equilibrium factor of 1.0 was used to

get more conservative break flow. To develop SBLOCA analysis methodology for OPR1000 using SPACE code, it was

necessary to use different non-equilibrium factor from SPACE default values for Henry-Fauske model. The SPACE code

was improved by adding additional option for Henry/Moody – Moody model, which uses user input non-equilibrium

factor. To accept user input equilibrium factor, the SPACE code is improved by expanding lookup table used in Henry/

Fauske – Moody model. To verify the new model, we perform verification calculations on LOFT L9-3 which is a

representative integral effect test(IET).

Experimental evaluation

Henry-Fauske critical model applied

to existing SPACE codes(NE=0.14)

will predict lower critical flow rates

over the period of transition from

subcooled liquid to two-phase

fluid compared to RELAP5 critical

flow models assuming a nonequilibrium(NE)

factor of 1.0.

Overview of LOFT L9-3


The LOFT L9-3[1] experimental

purpose is to provide experimental

data to developers of analysis codes

for ATWS analysis, evaluate alternative

methods of reaching long-term

shutdown without inserting control

rods after ATWS, and verify the

applicability of point kinetics model

or transients. In addition, the experimental

data provided is used to determine

the behavior characteristics of

the primary system due to loss of main

feedwater flow rate on the secondary

side of the steam generator and to

determine the two-phase and overcooling

flow characteristics released

through PORV and SRV at high


The LOFT L9-3 experimental

device is a 50MWt pressurized light

water reactor designed at a scale of

1/60 based on a 4-Loop Westinghousetype

nuclear power plant.

As shown in Figure 1 it consists of

five main components and subsystems,

including the reactor core,

primary coolant system, blowdown

mitigation system, emergency core

cooling system, and secondary cooling

system. The blowdown mitigation

system consists of a pump and steam

generator simulation device, a

Quick-opening discharge valve that

| Fig. 1.

LOFT Facility Schematic [Ref.1].

Research and Innovation

Improving Henry-Fauske Critical Flow Model in SPACE Code and Analysis of LOFT L9-3 ı BumSoo Youn

atw Vol. 66 (2021) | Issue 5 ı September

simulates a break, and a tank that

collects coolant released through a

break simulation valve.

The reactor core of the LOFT L9-3

experimental device is approximately

1/2 length(1.68m) of the commercial

reactor core, and the square core

group contains 21 guide tubes out of

225 rod positions(15×15).

Experimental Conditions

The LOFT L9-3 experimental conditions

begin at normal conditions,

such as core power of 48.7MWt, cold

leg temperature of 557.0K, hot leg

temperature of 576.4K, pressurizer

pressure of 14.98MP, and steam

generator pressure of 5.61MPa. The

key steady-state initial conditions of

the experiment are shown in Table 1.

LOFT L9-3 SPACE Modeling

SPACE modeling is shown in Figure 2.

SPACE code input from LOFT L9-3

experiments was written with

reference to NUREG/IA-0192[2]. The

reactor pressure vessel was divided to

simulate the upper and lower cavities

of the core bypass flow, and the core

was modeled as a non-fuel part in the

upper and lower part and a fuel part

represented by three vertical nodes.

The steam generator was modeled

by dividing it into 12 volumes for

U-tube and 19 volumes for secondary.

The main feedwater model was

modeled using TFBC Component,

especially the main feedwater and

steam flow parts, using control logic

to maintain constant pressure on the

secondary side.

The pressurizer was modeled with

nine volumes using the SPACE code

pressurizer model, and the surge line

under the pressurizer is connected to

cell C110 and the pressurizer spray

system is modeled with TFBC Component

C407 and C406. In particular,

Parameter Experiment SPACE

Mass flow rate(kg/s) 467.6 467.63

Hot leg pressure(MPa) 14.98 14.95

Cold leg temperature(K) 557.0 555.04

Hot leg temperature(K) 576.4 574.56

Power level(MWt) 48.7 48.7

PZR Liquid temperature(K) 615.2 614.78

PZR Pressure(MPa) 14.98 14.98

SG Liquid level(m) 3.15 3.19

SG Pressure(MPa) 5.61 5.55

SG Mass flow rate(kg/s) 25.7 25.6

| Tab. 1.

Initial value of experiment.

in the case of spray system, the spray

system is operated using the trip

signal so that fluid from cold

leg(C150) enters the pressurizer

through TFBC Component C407.

In the evaluation of LOFT L9-3

experiments using SPACE code, the

normal state was verified using null

transients, and then the transient

state was simulated using the Restart

file and the results were evaluated.

LOFT L9-3 Evaluation Results

Figure 3 shows the pressure change of

the pressurizer. According to the

experimental values in the figure, the

pressure of the system gradually

increases as the main feed water

supplied to the steam generator is

initially closed and the heat transfer

from the primary to the secondary

side of the steam generator decreases.

The pressurizer pressure increases

and reaches the setting of the pressurizer

spray system. When the setting

is reached, the pressurizer spray

system is activated and the pressurizer

pressure is reduced at 31 seconds. The

continuous decrease in heat transfer

to the steam generator causes the

pressure to rise again. The pressure of

the pressurizer is increased further as

the steam generator MSCV closes at

67.3 seconds. The pressurizer pressure

then reaches the opening setting of

the PORV and decreases when the

PORV is opened at 73.8 seconds.

However, due to the absence of a

replenishment of the main feedwater

of the steam generator, the pressure

rises again and the SRV setting of the


| Fig. 2.

LOFT L9-3 Facility Nodalization for SPACE Code Verification.

Research and Innovation

Improving Henry-Fauske Critical Flow Model in SPACE Code and Analysis of LOFT L9-3 ı BumSoo Youn

atw Vol. 66 (2021) | Issue 5 ı September


| Fig. 3.

Pressure change of the pressurizer.

pressurizer is reached at 96.8 seconds.

The pressurizer pressure reaches

the maximum pressure value at

97.5 seconds and then decrease. After

120 seconds, the pressurizer PORV

and SRV repeat open and close,

causing the pressure to repeat rise and

fall within a small range.

The SPACE predictions also show

similar results to the experimental

results. Initially, the main feedwater to

the steam generator is interrupted,

causing the pressurizer pressure to rise

just like the experiment. The pressure

that was decreasing due to the operation

of the pressurizer spray system

gradually increases again after the

spray system stops. The increased

pressure is reduced again in 55 seconds

by the operation of the spray system.

The MSCV of the steam generator

closes at 67.3 seconds, resulting in a

rapid increase in pressure as shown in

the experimental results. The pressure

then reaches the open setting of the

pressurizer PORV, which opened at

73.8 seconds, but continue to rise,

somewhat different from the experimental

value trend. The rising pressure

decreases at 90 seconds, but

without the com plement of the steam

generator’s main feedwater, the

pressure rises again and reaches a

| Fig. 4.

Pressure change of the steam generator.

maximum pressure slightly higher

than the experimental results at

103 seconds. Subsequently, the pressure

s reduced due to the operation of

the PORV, SRV, and pressurizer spray

systems of the steam generator, and

after 120 seconds, the rise and fall are

repeated near 15.5MPa to 16MPa.

The new Henry-Fauske critical

flow model shows more similar results

to experimental results than existing


Figure 4 shows the change in the

pressure of the steam generator.

According to the results of the

experiment, the pressure of the steam

generator will gradually increase as

the main feedwater of the steam

generator is closed. As the level of the

steam generator gradually decreases,

and steam generator U-tubes become

uncovered heat transfer area decreases,

and the pressure that was

gradually rising decreases rapidly. The

pressure then rises as MSCV closes.

The rising pressure of the steam

generator has slowed from about

100 seconds, when the PORV and SRV

discharge flow of the pressurizer were

maximum, and has since remained at

a constant pressure(6.48MPa) while

maintaining a slightly higher pressure

than the initial value.

As the main feedwater of the steam

generator is stopped, the SPACE result

is also a graual increase in pressure,

as is the result of the experiment.

Gradually rising pressure peaks at

50 seconds and decreases with a slope

similar to the experimental value.

However, with MSCV closing at

673 seconds, the SPACE code prediction

rises sharply from the experimental

value after approximately

70 seconds. The rising pressure of the

steam generator tends to be similar to

the experimental value after about

130 seconds and maintains a constant


Figure 5 shows the changes core

power. According to the experimental

results, if the main feedwater of the

steam generator is closed, the primary

system heat removal is lost and the

temperature and pressure of the

primary coolant are increased. As the

temperature of the coolant cooling

the core increases, the core power

decreases gradually due to the feedback

effect of the moderator. At

67.3 seconds, when the MSCV of the

steam generator is closed, the core

power is also rapidly reduced.

The SPACE code predictions tend

to decrease somewhat faster than the

experimental value between 70 and

| Fig. 5.

Core power change.

| Fig. 6.

Steam generator water level change.

Research and Innovation

Improving Henry-Fauske Critical Flow Model in SPACE Code and Analysis of LOFT L9-3 ı BumSoo Youn

atw Vol. 66 (2021) | Issue 5 ı September

| Fig. 7.

Coolant temperature change.

160 seconds, but the overall trend is

the same, and after 160 seconds, they

are almost the same.

Figure 6 shows the change in

water level on the secondary side of

the steam generator. According to the

results of the experiment, the water

on the secondary side of the steam

generator will be reduced due to heat

transfer with the primary side as the

main feedwater of the steam generator

is closed. The water level, which

had been continuously decreasing at

the same time as the main feed water

closed, will not completely depleted

after 120 seconds, and will gradually

stabilize at about 0.2 m high and

remain constant.

The overall trend predicted by the

SPACE code is similar to the experimental

results. However, the results of

the SPACE code begin to decrease in

water level and are almost depleted by

approximately 85 seconds. After that,

it remains completely depleted and in

a normal condition.

Figure 7 shows the temperature of

the coolant due to transient conditions.

Experimental results show

that the temperature of the coolant is

slowly increasing as the main feedwater

is closed. The increasing

temperature of the coolant rises

rapidly after 60 seconds due to the

continued loss of the heat sink, and

then the MSCV of the steam generator

closes at 67.3 seconds, which in creases

the temperature even more rapidly.

After 100 seconds, when the pressurizer

pressure is at its peak, the

pressure increase is slowed due to the

operation of SRV and PORV of the

pressurizer, and thus the temperature

increase is slowed. As the pressure of

the system is maintained constant, the

temperature of the coolant is maintained


As previously shown in Table 1,

the steady-state temperature conditions

using the SPACE code

| Fig. 8.

Discharge flow rate.

represent values about 2K lower than

the experimental conditions, so there

is a slight difference from the experiment

at the beginning of the transient

results. Although there is a difference

at the starting point, the result of

SPACE code also gradually increases

the temperature as the steam generator

main feedwater is stopped. As in

the experiment, the temperature rises

rapidly after 60 seconds, and remains

constant after 100 seconds.

Figure 8 shows the discharge flow

rate through PORV and SRV during

the transient. The main feedwater

stops, the pressure gradually rises,

and after 67.3 seconds the MSCV of

the steam generator closes, reaching

the opening set point of the PORV. At

100 seconds when the pressurizer

pressure reaches its maximum, the

discharge flow rate is maximum,

and after that, the PORV and SRV are

repeatedly opened and closed.

We compare the results with the

existing Henry-Fauske critical flow

model using the newly added Henry-

Fauske critical flow model in the

simulation with SPACE code for

discharge of coolant through the

PORV and the SRV. Overall, the

opening points are similar, but there

are some differences in the amount of

discharge. When using the newly

added Henry-Fauske critical flow

model, we can confirm that the

maximum discharge flow rate is

higher and conservatively predicted.


A new Henry/Fauske - Moody critical

flow model option was added to the

SPACE code. The SPACE code is

improved by expanding lookup table

used in Henry/Fauske - Moody model.

For validation of improved model,

LOFT L9-3 integral effect test is

analyzed. The new model show better

agreement with the experiment

results. The new critical flow model

will be used in the development of

SBLOCA analysis methodology of

OPR1000-type and WH 3-loop type

nuclear power plants.


This work was supported by the Korea

Hydro & Nuclear Power(KHNP)

(A19LP05, Establishment of optimal

evaluation system for safety analysis

of OPR1000and Westinghouse type

nuclear power plant(1)).




NUREG/CR-3427 ‘Experiment Analysis and Summary Report

for LOFT ATWS Experiments L9-3 and L9-4’.

NUREG/IA-0192 ‘Assessment of RELAP5/MOD3.2.2 Gamma

with the LOFT L9-3 Experiment Simulating an Anticipated

Transient without Scram’.


BumSoo Youn

Senior Researcher

Nuclear Safety

Analysis Group

Central Research

Institute, Korea Hydro

and Nuclear Power Co.,

LTD., Republic of Korea


BumSoo Youn studied Nuclear Engineering and

completed his M.S in 2009 at the Kyunghee University.

After graduation, he worked as a researcher at KEPRI

and have been working as a Senior Researcher at

KHNP since 2011. He does research in the following

areas: Nucelar Safety Analysis, Thermal Hydraulic

Analysis, Design Based Accident Analysis, Beyond

Design Based Accident Analysis.


Research and Innovation

Improving Henry-Fauske Critical Flow Model in SPACE Code and Analysis of LOFT L9-3 ı BumSoo Youn

atw Vol. 66 (2021) | Issue 5 ı September


Non-destructive Radioactive Tracer

Technique in Evaluation of Photodegraded

Polystyrene Based Nuclear

Grade Ion Exchange Material

Pravin U. Singare

1 Introduction Poly styrene-divinyl benzene type ion exchange materials having sulfonic acid and quaternary

ammonium functional groups are widely used in various nuclear industries related applications where prolonged

service in adverse environmental condition is required. In nuclear industrial applications organic resin materials are

used for elimination of radioactive and other ionic impurities from water in moderator circuits [1]. In view of the

extensive application of organic ion exchange materials in nuclear industries, their technological development started

long back and are now made available at commercial scale to satisfy the needs of these industries. In spite of widespread

applications of ion exchange materials, there are some problems related to their durability over a prolonged time

period. The consistent performance of these materials depends upon the chemical nature of polymeric resin material,

adverse environmental factors namely humidity, acid rain, temperature fluctuation and time of exposure to ultraviolet

(UV) radiation, presence of traces of solvents, catalyst, metals and metal oxides from processing equipment and

containers. In outdoor applications, these ion exchange materials very often deteriorate due to weathering process

creating negative impact on their lifetime [2, 3]. The inability of polymeric resin materials to resist degradation

conditions often becomes visible within a short span. In some situations, few hours of exposure to degradation

conditions may result in extensive structural damage. The degradation process may lead to macromolecular chain bond

breaking resulting in decrease in average molar mass or may lead to cross-linking thereby increasing the molar mass.

Aging of polymeric materials will result alteration of polymer properties in long-term due to weathering conditions [4].

As a result, there is an increasing challenge in front of manufacturers to ensure about the life expectancy guarantee of

their polymeric resin materials, particularly under the conditions which are difficult for inspection or failure catastrophic

[5]. The wide spread utilization of polymeric resin materials has created the condition of emergence related to

performance durability of these materials under stringent long-term exposure conditions. These problems related to

durability of polymeric resin materials are associated with in-service environmental conditions and handling procedures

during maintenance, repair and modifications. Since the repair or replacement of degraded polymeric resin materials

is both labour and capital intensive, the durability of these materials is one of the critical issues from both safety and

economic point of view.

The photo-degradation brought

about by solar UV radiations is the

most serious problem associated with

an organic based resin. The solar

waves consist of UV radiations in the

wavelengths range of 290 to 400 nm,

corresponding to the energies in the

range of 415 to 300 kJ/mol. These

energies associated with the solar UV

radiations are similar to the bond

energies of many organic molecules.

When specific functional groups of

an organic compound absorb UV

radiation the chemical reactions

are initiated liberating free radicals

which further speedup the photo

degradation process. Among the UV

radiations, most harmful are the UV-B

radiations which are in the wavelength

range of 280 to 315 nm having

high energy in the order of

426-380 KJ mol -1 , while UV-A radiations

in the wavelength range of 315

to 400 nm are less harmful having

comparatively less energy in the order

of 389 and 300 KJ mol -1 [6]. The

deleterious effect of these radiations

will depend on the chemical nature of

the material, climatic conditions

namely temperature, humidity, exposure

time, presence of traces of

solvents, catalyst, metals and metal

oxides from processing equipment

and containers [7]. Photo-degradation

can take place via chain breaking

or cross-linking in absence of oxygen

and via photo-oxidative degradation

in presence of oxygen. In most

polymers, elevation in temperature

condition and prolonged exposure

to pollutants will raise the photooxidative

sensitivity thereby triggering

the photo-oxidative degradation

process [8]. Exposure to UV radiations

is usually observed superficially which

is indicated in terms of embrittlement

(surface cracking), discolouration

and loss of transparency. Further

exposure to UV radiations will bring

about photolytic, photo-oxidative, and

thermo-oxidative reactions in the

resin materials resulting in the

photo-degradation of polymeric resin

materials which is usually superficially

and slowly degrades the entire

material by changing the chemical

structure of the polymeric material

[9]. Depending upon the nature of the

polymeric resin material, the photo

degradation may results in polymer

chain scission, cross-linking leading

to irreversible change in physicochemical

conditions and also changes

at the molecular level [10]. Subsequent

to UV exposure, the polymeric

resin material follows different degradation

routes via formation of free

radicals and breaking of the polymer

chains thereby losing its mechanical

properties and molecular weight

making the materials useless after

some time [11].

The photo degradation of industrial

grade ion exchange resins operating

under severe environ mental stress

conditions is a serious problem with

economic and environmental implications.

Previous research focused

mainly on the study of bulk mechanical

properties, surface chemistry

and surface morphology of the

polymeric materials exposed to UV

radiations for different exposure

period [12, 13]. The study was also

performed to understand the role

of sensitizers in accelerating the

efficiency of the photo-degradation

Research and Innovation

Non-destructive Radioactive Tracer Technique in Evaluation of Photo- degraded Polystyrene Based Nuclear Grade Ion Exchange Material ı Pravin U. Singare

atw Vol. 66 (2021) | Issue 5 ı September

and the mechanism of UV light

induced photo-oxidation and photolysis

processes in polymeric materials

[14, 15]. A detail review was published

on photo-degradation of polystyrene

polymers which emphasise mainly

on the degradation mechanism of

polymers and role of stabilisers in

photo- degradation [16]. However, in

spite of extensive application of

polymeric resin materials in nuclear as

well as in the chemical industry, not

much work is reported in the literature

related to performance of photodegraded

polymeric resin materials

[17]. Therefore, in the present investigation,

a systematic study was

performed on the ion uptake reaction

kinetics and uptake behaviour of fresh

and photo-degraded nuclear grade anion

exchange resin Indion GS 300, using

non-destructive radiotracer

analytical technique.

2 Materials and Methods

2.1 Ion exchange resin

The anion exchange resin Indion GS-

300 as supplied by the manufacturer

(Ion exchange India Limited,

Mumbai) was a nuclear grade resin

in the OH-form with quaternary

ammonium functional group having

polystyrene matrix. The particle size

was in the range of 0.3 to 1.2 mm,

operating pH range was 0-14,

maximum operating temperature of

60 °C having the exchange capacity of

1.40 meq./mL. The moisture content

of the resin was 51.9 %.

2.2 Radio isotope used

The 82 Br radioactive tracer isotope

used here was supplied by Board of

Radiation and Isotope Technology

(BRIT), Mumbai, India. The isotope

used is an aqueous solution of

ammonium bromide in dilute

ammonium hydroxide having half life

of 36 d, radioactivity of 5mCi and

γ-energy of 0.55 MeV [18].

2.3 Conditioning

of the ion exchange resin

The resin grains of 30-40 mesh size

were used for the present investigation.

The soluble impurities of the

resin were removed by repeated

soxhlet extraction using water. Moreover,

distilled methanol was used

occasionally to remove non-polymerized

organic impurities. The resin

in hydroxide form was converted into

bromide form with 10 % potassium

bromide in a conditioning column.

Then the resin was washed with

distilled deionized water until the

washings were bromide free. The

resin in the bromide form was air

dried over P 2 O 5 and used for further

study (hereafter referred as fresh


2.4 Photo-degradation of ion

exchange resin

The photo-degradation of the resin

was carried in a UV chamber in an

ambient atmosphere where the

temperature was nominally 25 °C-

29 °C, with a humidity of 30-50 %.

The resin was photo-degraded in a UV

chamber by exposing them to radiation

of wavelength 284 nm and

384 nm for 24 h. After 24 h the

degraded resin was washed with

distilled water and ethanol mixture to

remove the degraded polymeric

fractions. The resin was then air dried

and used for further study (hereafter

referred as λ 384 photo degraded resin

and λ 284 photo degraded resin).

2.5 Study on bromide ion uptake

and reaction kinetics

The fresh and degraded resins in

bromide form weighing 1.000 g (m)

were equilibrated with 200 mL (V)

labeled bromide ion reaction medium

(0.200M) of known initial activity

(Ai) at a constant temperature of

30.0 °C. The temperature of the

reaction medium was maintained

constant using an in-surf water bath.

The bromide ion-isotopic exchange

reaction can be represented as:

R-Br + Br* - (aq.) ⇌ R-Br* + Br - (aq.)


Here R-Br represents ion exchange

resin in bromide form; Br* - (aq.) represents

aqueous bromide ion reaction

medium labeled with 82 Br radiotracer


The activity in counts per minute

(cpm) of 1.0 mL of the reaction

medium was measured at an interval

of every 2 minutes for 3 h. The solution

was transferred back to the same bottle

containing labeled reaction medium

after measuring the activity. The final

activity (A f ) of the equili brated labeled

bromide ion reaction medium was

measured after 3h. The activity in

counts per minute (cpm) was measured

with γ-ray spectro meter equipped with

NaI (Tl) scintillation detector. The

activity measured at various time intervals

was corrected for background

counts. The procedure adopted for

labeling the reaction medium was

same as mentioned previously [19].

The percentage and amount of bromide

ions exchanged on the resin in

mmol were obtained from the A i , A f ,

values and the amount of exchangeable

bromide ions in 200 mL of reaction

medium. The study was extended

further by equilibrating the fresh and

degraded resins with 0.300M and

0.500M labeled bromide ion reaction

medium at 30.0 °C. Similar set of

experiments were repeated by equilibrating

1.000 g of fresh and degraded

resins in bromide form with 0.200M

labeled bromide ion reaction medium

at higher temperatures up to 45.0 °C.

2.6 Fourier-transform infrared

spectroscopy (FTIR) analysis

FTIR analysis of fresh and photodegraded

resins was performed using

a Bruker Optik, ALPHA-T FTIR

spectrometer having gold mirror

interferometer with ZnSe beam

splitter. The ATR probe consisted of a

zinc selenide focusing element and a

diamond internal reflectance element.

The probe was brought into intimate

contact with the sample surface using

mechanical pressure. 32 scans were

collected over the spectral range of

400 cm -1 to 4000 cm -1 . The probe was

purged with dry air and background

spectra were collected before each

sample spectrum was taken.

2.7 Scanning Electron

Microscopy (SEM) analysis

The degradation studies of ion

exchange resins was also studied by

examining the surface morphology of

fresh and photo degraded resin

samples using JSM-6380LA Scanning

Electron Microscope (Jeol Ltd.,

Japan). The powders were precisely

fixed on an aluminum stub using

double sided graphite tape and then

were made electrically conductive by

coating in a vaccum with a thin layer

of carbon, for 30 seconds and at 30 W.

The pictures were taken at an

excitation voltage of 15 KV and a

magnification of ×250 to ×500.

3 Results and Discussion

3.1 Effect of photo-degradation

on isotopic ion uptake

reaction kinetics

In the present investigation it was

observed that the initial activity of

solution decreases rapidly due to

rapid ion uptake reaction, then due to

slow ionic uptake the activity of the

solution decreases slowly due and

finally remains nearly constant.

Previous investigations have shown

that the above ionic uptake reactions

are of first order, as a result the

logarithm of activity when plotted


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against time gives a composite curve

in which the activity initially decreases

sharply and thereafter very

slowly giving nearly straight line,

evidently rapid and slow ion adsorption

reactions were occurring simultaneously

[19]. The activity exchanged

due to rapid, slow uptake reactions as

well as the specific reaction rate (k)

of rapid ion uptake reactions were

calculated in the same way as

explained previously [20-22]. The

amount of bromide ions exchanged

(mmol) on the resin were obtained

from the initial and final activity of

solution and the amount of ions in

200mL of solution.

It was observed that, under identical

experimental conditions, with rise

in temperature from 30.0 °C to 45.0 °C,

the k values (min -1 ) for bromide ion

uptake reactions were observed to decrease

for fresh as well as for λ 384 and

λ 284 photo- degraded resins (Table 1).

Thus for 0.200M bromide ion concentration

when the temperature was

raised from 30.0 °C to 45.0 °C, the k

values decrease from 0.238 to 0.226

min -1 for fresh resin, from 0.198 to

0.181 min -1 for λ 384 photo-degraded

resin and from 0.156 to 0.142 min -1 for

λ 284 photo-degraded resin (Table 1).

It was observed that, under identical

experimental conditions, with rise

in concentration of bromide ions in

the solution from 0.200M to 0.500M,

the k values (min -1 ) for ion uptake

reactions were observed to increase

for fresh as well as for λ 384 and λ 284

photo-degraded resins (Table 2).

Thus at 30.0 °C when the bromide

ion concentration was raised from

0.200M to 0.500M, the k values increase

from 0.238 to 0.276 min -1 for

fresh resin, from 0.198 to 0.223 min -1

for λ 384 photo-degraded resin and

from 0.156 to 0.176 min -1 for λ 284

photo-degraded resin (Table 2).

From the results, it appears that

under identical experimental conditions,

ion uptake reaction rate

decreases sharply as the photodegradation

wavelength decreases

from 384 nm to 284 nm. Thus for

0.200M bromide ion concentration at

a constant temperature of 30.0 °C, the

k value was 0.238 min -1 for fresh

resin, which decreases to 0.198 min -1

for λ 384 photo-degraded resin, which

further decreases to 0.156 min -1 for

λ 284 photo-degraded resin (Table 1).

Comparing the ion uptake reaction

rate (k) in min -1 for reactions

performed at different temperatures

of reaction medium and concentration

of labeled bromide ion solution,

it was observed that the k values

decrease with decrease in photodegradation



of reaction




rate of rapid


ion uptake


(min -1 )

Fresh resin λ 284 photo degraded resin λ 384 photo degraded resin


of isotopic

ions uptake


% of





rate of rapid


ion uptake


(min -1 )


of isotopic

ions uptake


% of





rate of rapid


ion uptake


(min -1 )


of isotopic

ion uptake


% of




30.0 0.238 21.9 54.8 0.156 18.4 45.9 0.198 20.2 50.5

35.0 0.233 19.9 49.7 0.152 15.1 37.8 0.19 18.1 45.3

40.0 0.229 17.8 44.6 0.147 11.9 29.7 0.186 16.0 40.1

45.0 0.226 16.1 40.3 0.142 8.6 21.6 0.181 14.0 34.9

Energy of


(kJ.mol -1 )

Enthalpy of


(kJ.mol -1 )

Free energy of


(kJ.mol -1 )

Entropy of


(kJ.K -1 mol -1 )

-2.77 -5.05 -4.66

-5.35 -7.63 -7.24

64.66 63.65 63.86

-0.231 -0.236 -0.234

| Tab. 1.

Effect of temperature of reaction medium on isotopic ion uptake reaction kinetics and isotopic uptake using fresh/photo-degraded Indion GS 300 resins.

Amount of ion exchange resin in bromide form = 1.000 g; Concentration of labeled bromide ion reaction medium = 0.200M; Volume of labeled bromide ion reaction medium = 200 mL;

Amount of exchangeable bromide ions in 200 mL labeled reaction medium = 40.00 mmol.


of ions

in the





of ions in

200 mL





rate of



ion uptake


(min -1 )

Fresh resin λ 284 photo degraded resin λ 384 photo degraded resin


of isotopic




% of





rate of



ion uptake


(min -1 )


of isotopic




% of





rate of



ion uptake


(min -1 )


of isotopic

ion uptake


% of




0.200 40.00 0.238 21.9 54.8 0.156 18.4 45.9 0.198 20.2 50.5

0.300 60.00 0.250 35.5 59.2 0.162 29.8 49.6 0.207 32.6 54.4

0.500 100.00 0.276 68.7 68.7 0.176 56.7 56.7 0.223 63.8 63.8

| Tab. 2.

Concentration effect on isotopic ion uptake reaction kinetics and isotopic uptake using fresh/photo-degraded Indion GS 300 resins.

Amount of ion exchange resin = 1.000 g; Volume of labeled ionic reaction medium = 200 mL; Temperature of reaction medium = 30.0 °C.

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3.2 Effect of photodegradation

on percentage

isotopic ion uptake

It was observed that for 0.200M

labeled bromide ion solution, as the

temperature of the reaction medium

increases from 30.0 °C to 45.0 °C, the

percentage of isotopic ion uptake

decreases by 14.5 % from 54.8 % to

40.3 % for fresh resins; by 15.6 % from

50.5 % to 34.9 % for λ 384 photodegraded

resin and maximum by

24.3 % from 45.9 % to 21.6 % for

λ 284 photo-degraded resin (Table 1).

For same temperature of reaction

medium, similar decrease in percentage

of bromide ion uptake was

observed as the photo-degradation

wavelength decreases from 384 nm to

284 nm. Thus for 0.200M labeled

bromide ion solution at a constant

temperature of 30.0 °C, in case of

fresh resin the percentage of ion

uptake was 54.8 %, while for λ 384

photo- degraded resin 50.5 % isotopic

ion uptake was observed, indicating

4.3 % decrease. Similarly, for λ 284

photo-degraded resin, the percentage

of isotopic ion uptake was 45.9 %

indicating 8.9 % decrease with

reference to fresh resin (Table 1).

Thus, it was observed that the

decrease in wavelength has higher

photo-degradation effect on the

resin which is reflected by higher

decrease in bromide ion uptake by the


It was observed that at 30.0 °C, as

the concentration of labelled bromide

ion solution increases from 0.200M to

0.500M, the percentage of isotopic ion

uptake increases by 13.9 % from

54.8 % to 68.7 % for fresh resins; by

13.3 % from 50.5 % to 63.8 % for λ 384

photo-degraded resin and by 10.8 %

from 45.9 % to 56.7 % for λ 284 photodegraded

resin (Table 2). Thus, as

the photo-degradation wavelength

decreases the degradation effect on

the resin was more which is reflected

by less increase in isotopic ion uptake

by the resin.

3.3 Thermodynamics of isotopic

ion uptake reactions

using fresh and photodegraded


The energy of activation (E a ) for the

bromide ion uptake reactions taking

place in Indion GS 300 were calculated

by using Arrhenius equation


k = A × e -Ea/RT (2)

The plot of log (10) k against 1/T gives a

straight line graph (Figure 1), from

the slope of the plot, energy of activation

E a values for ion uptake reactions

using fresh and photo- degraded resins

were calculated by the equation [23].

E a = slope × -2.303x R (3)

The enthalpy of activation ΔH ‡ value

for the bromide ion uptake reactions

using fresh and photo-degraded resins

were calculated by using the Eyring-

Polanyi equation [23, 24].

log 10 k/T = -ΔH ‡ /2.303RT +

log 10 k B /h + ΔS ‡ /2.303R



k = reaction rate constant

T = absolute temperature

ΔH ‡ = enthalpy of activation

R = gas constant (8.314J.K -1 .mol -1 )

k B = Boltzmann constant

(1.3806 ×10 -23 J⋅K -1 )

h = Planck’s constant

(6.6261×10 -34 J⋅s)

ΔS ‡ = entropy of activation


The plot of log 10 k/T versus 1/T gives a

straight-line graph (Figure 2), from

the slope of which enthalpy of

activation ΔH ‡ values for the bromide

ion uptake reactions using fresh and

photo-degraded resins were calculated

by the equation

Slope = ΔH ‡ /-2.303R (5)

| Fig. 1.

Arrhenius plot to determine energy of activation (Ea) for bromide isotopic ion uptake reactions

performed by using fresh and photo-degraded Indion GS 300 resins.

Amount of ion exchange resin in bromide form = 1.000 g; Temperature range = 30.0-45.0 °C; Concentration of labeled

exchangeable bromide ion solution = 0.200M; Volume of labeled bromide ion solution = 200 mL; Amount of exchangeable

bromide ions in 200 mL labeled solution = 40.00 mmol.

From the intercept of the above plot,

the entropy of activation ΔS ‡ values

for the bromide ion uptake reactions

using fresh and photo-degraded resins

were calculated by the equation

Intercept = 2.303 × log 10 (k B /h)

+ ΔS ‡ /R(6)

Knowing the values of enthalpy of

activation ΔH ‡ and entropy of activation

ΔS ‡ , free energy of activation ΔG ‡

for bromide ion uptake reactions

using fresh and photo-degraded resins

was calculated by the equation

ΔG ‡ = ΔH ‡ -TΔS ‡ (7)

| Fig. 2.

Eyring-Polanyi plot to determine the enthalpy of activation ΔH ‡ and entropy of activation ΔS ‡ for bromide

isotopic ion uptake reactions performed by using fresh and photo-degraded Indion GS 300 resins.

Amount of ion exchange resin in bromide form = 1.000 g; Temperature range = 30.0-45.0 °C; Concentration of labeled

exchangeable bromide ion solution = 0.200M; Volume of labeled bromide ion solution = 200 mL; Amount of exchangeable

bromide ions in 200 mL labeled solution = 40.00 mmol.

It was observed that during isotopic

ion uptake reactions using the fresh

resin, the values of energy of activation

(-2.77 kJ.mol -1 ), enthalpy of activation

(-5.35 kJ.mole -1 ), free energy of activation

(64.66 kJ.mol -1 ) and entropy

of activation (-0.231 kJ.K -1 mol -1 );

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| Fig. 3.

Correlation between temperature of reaction medium and bromide isotopic ion uptake reaction rate of

the reactions performed by using fresh and photo-degraded Indion GS 300 resins.

Amount of ion exchange resin in bromide form = 1.000 g; Concentration of labeled bromide ion reaction medium = 0.200M;

Volume of labeled bromide ion reaction medium = 200 mL; Amount of exchangeable bromide ions in 200 mL labeled reaction

medium = 40.00 mmol

Correlation coefficient (r) for fresh resin =-0.9938; Correlation coefficient (r) for λ 384 photo degraded resin =-0.9886;

Correlation coefficient (r) for λ 284 photo degraded resin = -0.9986

| Fig. 4.

Correlation between temperature of reaction medium and percentage of bromide isotopic ion uptake for

the reactions performed by using fresh and photo-degraded Indion GS 300 resins.

Amount of ion exchange resin in bromide form = 1.000 g; Concentration of labeled bromide ion reaction medium = 0.200M;

Volume of labeled bromide ion reaction medium = 200 mL; Amount of exchangeable bromide ions in 200 mL labeled reaction

medium = 40.00 mmol

Correlation coefficient (r) for fresh resin =-0.9992; Correlation coefficient (r) for λ 384 photo degraded resin =-1.0000;

Correlation coefficient (r) for λ 284 photo degraded resin = -1.0000

| Fig. 5.

Correlation between concentration of labeled bromide ionic solution and bromide isotopic ion uptake

reaction rate of the reactions performed by using fresh and photo-degraded Indion GS 300 resins.

Amount of ion exchange resin = 1.000 g; Volume of labeled ionic reaction medium = 200 mL;

Temperature of reaction medium = 30.0 °C

Correlation coefficient (r) for fresh resin = 0.9998; Correlation coefficient (r) for λ 384 photo degraded resin = 0.9995;

Correlation coefficient (r) for λ 284 photo degraded resin = 0.9993

which increases to -4.66 kJ.mol -1 ,

-7.24 kJ.mol -1 , 63.86 kJ.mol -1 and

-0.234 kJ.K -1 mol -1 respectively for

λ 384 photo-degraded resin; which further

increases to -5.05 kJ.mol -1 , -7.63

kJ.mol -1 , 63.65 kJ.mol-1 and -0.236

kJ.K -1 mol -1 respectively for λ 284 photo-degraded

resin under similar

experimental conditions (Table 1).

The thermodynamic parameters calculated

here suggest that decrease in

wavelength of UV radiations has

more degradation effect on the resin

re sulting in less thermodynamic

feasibility of the isotopic ion uptake


3.4 Statistical Correlations

The results of present investigation

show a strong negative correlation

between temperature of the medium

and bromide ion uptake reaction rate

(min -1 ) for the reactions performed

by using fresh, λ 284 photo degraded

and λ 384 photo degraded resins,

having r values of -0.9938, -0.9986

and -0.9886 respectively (Figure 3).

There also exist strong negative

correlation between percentage of

bromide ion uptake and temperature

of the medium for the reactions performed

by using fresh, λ 284 photo

degraded and λ 384 photo degraded

resins, having r values of -0.9992,

-1.0000 and -1.0000 respectively

(Figure 4).

However, a strong positive correlation

was observed between the concentration

of labeled ionic medium

and bromide ion uptake reaction rate

(min -1 ) for the reactions performed by

using fresh, λ 284 photo degraded and

λ 384 photo degraded resins, having r

values of 0.9998, 0.9993 and 0.9995

respectively (Figure 5). Also, a strong

positive correlation was observed

between the concentration of labeled

ionic medium and percentage of

bromide ion uptake for the reactions

performed by using fresh, λ 284 photo

degraded and λ 384 photo degraded

resins, having r values of 0.9998,

0.9999 and 0.9990 respectively

(Figure 6).

3.5 Characterisation of fresh

and photo-degraded resin

| Fig. 6.

Correlation between concentration of labeled bromide ionic solution and percentage of bromide isotopic

ion uptake for the reactions performed by using fresh and photo-degraded Indion GS 300 resins.

Amount of ion exchange resin = 1.000 g; Volume of labeled ionic reaction medium = 200 mL;

Temperature of reaction medium = 30.0 °C

Correlation coefficient (r) for fresh resin = 0.9998; Correlation coefficient (r) for λ 384 photo degraded resin = 0.9990;

Correlation coefficient (r) for λ 284 photo degraded resin = 0.9999

3.5.1 FTIR spectrum of fresh and

photo-degraded Indion GS

300 resin

The IR spectrum of the fresh Indion

GS 300 resin is shown in Figure 7. The

assignments of various bands and

peaks made in this study are in

reasonable agreement with those

reported in the literature for similar

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functional groups. In the FTIR

spectrum of fresh resin, the sharp

strong broad band was observed at

3366 cm -1 corresponding to the

vibration of O-H bond of the water or

the quaternary ammonium group

(R 4- N + ). This may be due to the

moisture content of the fresh resins.

The sharp band between 1380-

1349 cm -1 was for -C-N stretching

while a variable absorption bands

between 1633-1614 cm -1 was due to

the stretching vibrations of -C=C- of

alkenes group. The weak band at

3031 cm -1 was the characteristic

stretching band for aromatic ring. A

moderate band at 2925 cm -1 was due

to the C-H stretching band for -CH 2

group. A moderate and sharp band at

1416 cm -1 and 1470 cm -1 was due to

the -C-H bending bands for -CH 2

group. The variable band at 1511 cm -1

was the -C=C- stretching for aromatic

ring, the sharp band at 828 cm -1 and

moderate band at 705 cm -1 was the

characteristic bands of p-substituted

and o-substituted aromatic rings.

Comparison of IR spectrum of fresh

resin (Figure 7) and photo-degraded

resin (Figures 8 and 9) indicate

disappearance of characteristic -C-N

stretching band at 1349 cm -1 , -C-H

stretching band at 3031 cm -1 for

aromatic ring and a single band at

1614 cm -1 for -C=C- stretching in


| Fig. 7.

FTIR Spectrum of fresh Indion GS 300 resin.

| Fig. 8.

FTIR Spectrum of λ 284 photo-degraded Indion GS 300 resin.


3.5.2 SEM study of fresh and

photo-degraded Indion GS

300 resin

The SEM image of fresh ion exchange

resins Indion GS 300 was taken to

examine its surface morphology. The

Figure 10(a) showed the surface

morphology of fresh Indion GS 300

resins which indicate its plane spherical

structure having smooth surface.

The SEM image of λ 384 and λ 284

photo-degraded Indion GS 300 resin

showed large cracks on the plane

spherical surface of the resin (Figures

10b and 10c). The SEM image of λ 384

photo-degraded resin show hair cracks

on the surface (Figure 10b). Whereas,

in case of λ 284 photo- degraded resin,

the completely broken surface with

large cracks were observed (Figure

10c), indicating higher photo-degradation

effect as compared to that of

the fresh and λ 384 photo-degraded

resin (Figures 10a and 10b).


In recent years, the industrial application

of polymeric resin materials has

increased considerably but it is now

well established that these materials

| Fig. 9.

FTIR Spectrum of λ 384 photo-degraded Indion GS 300 resin.

undergo rapid photo-degradation

when exposed to solar UV radiations.

The photo-degradation of resin materials

is one of the most serious

problems associated with an organic

based resin. Among the solar UV

radiations, most harmful are the high

energetic UV-B radiations (280 to

315 nm) in comparison to UV-A

radiations (315 to 400 nm) which are

of less energy. The polymeric resin

material Indion GS 300 in the present

study after exposure to UV radiation

of wavelength 284 and 384nm was

studied for the percentage isotopic ion

uptake, reaction kinetics and reaction

thermodynamics. The results of the

present investigation indicate that

isotopic ion uptake reaction rate

(min -1 ), percentage of isotopic ion

uptake are greatly affected for the

reactions performed by using λ 284 and

λ 384 photo degraded Indion GS 300

resin as compared to that of fresh

Indion GS 300 resin. The increase

in thermodynamic parameters like

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| Fig. 10a.

SEM image of fresh Indion GS 300 resin.

energy of activation (kJ.mol -1 ),

enthalpy of activation (kJ.mol -1 ), free

energy of activation (kJ.mol -1 ) and

entropy of activation (kJ.K-1mol -1 )

calculated for the isotopic ion uptake

reactions using the fresh, λ 384 and λ 284

photo degraded Indion GS 300 resin

give an indication that decrease in

wavelength of UV radiations has

catastrophic effect on the resin

resulting in less thermodynamic

feasibility of the isotopic ion uptake



The author is thankful to Professor

Dr. R.S. Lokhande (Retired) for his

valuable help and support by providing

the required facilities so as

to carry out the experimental work

in Radiochemistry Laboratory, Department

of Chemistry, University

of Mumbai, Vidyanagari, Mumbai

-400 058.


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| Fig. 10c.

SEM image of λ 284 photo-degraded Indion

GS 300 resin.



Pravin U. Singare

Associate Professor


Department of


N.M. Institute of Science,

Bhavan’s College,

Mumbai, India

Pravin U. Singare has worked extensively on

characterization of nuclear and non-nuclear grade ion

exchange resins using radioactive tracer technique.

He is the member of Indian Society of Analytical

Scientists, National Association for Application of

Radio Isotopes and Radiation in Industry (NAARI),

Indian Nuclear Society (INS), and Indian Association

of Nuclear Chemists & Allied Scientists (IANCAS) all

from Bhabha Atomic Research Centre, (B.A.R.C.),

Anushaktinagar, Mumbai, and Indian Council of

Chemists (ICC), Agra, India.

Research and Innovation

Non-destructive Radioactive Tracer Technique in Evaluation of Photo- degraded Polystyrene Based Nuclear Grade Ion Exchange Material ı Pravin U. Singare


Water in Nuclear Power Plants with Light-Water Reactors

Part 1: Pressurised-Water Reactors. Part 2: Boiling-Water Reactors.

(formerly VGB-R 401)

Edition 2020 – VGB-S-401-00-2020-05-EN (VGB-S-401-00-2020-05-DE, German edition)

DIN A4, Print/eBook*, 92 Pages, Price for VGB-Members € 180.–, for Non-Members € 270.–, + Shipping & VAT

Almost half a century after publication of the first edition of a VGB-Guideline for the Water in Nuclear

Power Plants with Light-Water Reactors and approx. 13 years after the third edition in 2006, the task

of a renewed adaptation of the Guideline for the Water in Light-Water Reactors as VGB-Standard arises.

This VGB-Standard shall be the common basis for the operation of the plants. It provides the framework

for operating manuals or chemical manuals, but is in no way intended to replace them.

The task of these manuals is, among other things, to consider plant-specific features and to make

specifications that go beyond this VGB-Standard.

This VGB-Standard describes the water-chemical specification for the safe operation of light-water

reactors based on the material concept of the Siemens/KWU and comparable plants.

The revision takes into account, where appropriate, the knowledge and experience gained over the

last decade in the national and international environment.


for the Water in Nuclear

Power Plants with

Light-Water Reactors

Part 1: PWR

Part 2: BWR

(Formerly VGB-R 401)


Notice: A background paper (VGB-S-401-91-2020-05-EN) with further notes and summarised experiences will be available in July 2021.

Part 1, PWR. Contents (abbreviated)

1 Field of application

2 Definitions

2.1 General

2.2 Definition of the Action Levels for the reactor coolant circuit

2.3 Definition of the Action Levels for the water-steam cycle

2.4 Definition of the Action Areas for the water-steam cycle

2.5 Overview diagram of a PWR plant

3 Reactor coolant circuit

3.1 Fundamentals of reactor coolant chemistry

3.2 Explanations

3.3 Specifications

3.4 Special treatment methods

4 Water-steam cycle

4.1 Fundamentals of the chemistry of the water-steam cycle

4.2 Control parameters for start-up operation

4.3 Diagnostic parameters for start-up operation

4.4 Control parameters for continuous operation

4.5 Integral control parameters for continuous operation

4.6 Diagnostic parameters for continuous operation

4.7 Diagnostic parameters for make-up water

4.8 Specification of the media of the water-steam cycle

4.9 Special treatment methods and measurements

5 Literature

6 List of abbreviations

7 Annex 1: Overview main cooling circuit

8 Annex 2: Overview water/steam cycle

Part 2, BWR. Contents (abbreviated)

1 Field of application

2 Definitions

2.1 Control parameters

2.2 Diagnostic parameters

2.3 Normal operating values

2.4 Tolerable range

2.5 Action Levels

3 Fundamentals of chemistry in the reactor system and

in the water-steam cycle

3.1 Total overview

3.2 Reasons for the high chemical demands requirements on

the water-steam cycle including reactor water

3.3 Explanation of the chemical parameters for the reactor water and the water-steam cycle during plant operation

3.4 Explanation of the chemical parameters for reactor water in cold condition (< 100 °C) and for start-up readiness,

as well as for feed water before start-up

4 Specification values for reactor water and water/steam cycle

5 Specification values for auxiliary and secondary systems

6 Literature

* Access for eBooks (PDF files) is included in the membership fees for Ordinary Members (operators, plant owners) of VGB. www.vgb.org/vgbvs4om

VGB PowerTech Service GmbH

Verlag technisch-wissenschaftlicher Schriften

Deilbachtal 173 | 45257 Essen | Germany

Fon: +49 201 8128-200 | Fax: +49 201 8128-302 | E-Mail: mark@vgb.org | www.vgb.org/shop

atw Vol. 66 (2021) | Issue 5 ı September




Nuclear making Europe

fit for 55

(nei) FORATOM welcomes the

Commission’s Fit for 55 package and

fully supports all proposals which aim

to reduce CO 2 emissions in line with

the Climate Law and Paris Agreement.

Indeed, the bar has been set very high

as it will apply to a broad range of

sectors including industry, buildings

and transport.

“Achieving this target will not be

easy – many aspects need to be taken

into consideration to ensure that, in

the race to decarbonisation, other

problems do not arise”, states Yves

Desbazeille, FORATOM Director


For example:

p How will be this transition


p Will we have enough low-carbon

energy to meet our needs?

p How can we ensure that industries

are able to decarbonise their

manufacturing processes whilst

remaining competitive?

p And how can we mitigate potential

social impacts (eg job losses,

energy poverty)?

Nuclear has a key role to play in

this transition, together with other

low- carbon technologies” adds Mr

Desbazeille. “It is a low-carbon source

of energy, thus helping European

achieve its decarbonisation targets. It

is also affordable and available 24/7,

two key attributes when it comes to

finding competitive solutions for

energy-intensive industries in Europe”.

The nuclear sector remains committed

to working with the EU and

supporting technology neutral policies

which will help us achieve these

ambitious goals. Furthermore, and as

highlighted in the latest IEA and

OECD NEA report entitled ‘Projected

Costs of Generating Electricity 2020’,

the long-term operation of nuclear

power plants remains the cheapest

source of electricity across the board.

Therefore, prolonging the existing

fleet would be the best way of

achieving the 2030 targets in an

affordable manner.

| www.foratom.org (211711803)

NEI: Advanced Nuclear will

Balance Energy Supply and


(nei) As we prepare for a decarbonized

grid with more wind and solar,

it’s critical to prepare a way to balance

energy supply, which varies over the

course of the day, with demand.

Demand varies too, but on a different


Balancing supply with demand has

always been essential to ensuring a

reliable grid. Energy use varies from

minute to minute, driven by people’s

use of air conditioning, heating,

lighting and other devices. Today, the

energy system meets those changes by

shifting how much fossil fuel it is


In solar intensive locations like

California, copious energy from the

sun at midday leads utilities to shut

Operating Results May 2021

Plant name Country Nominal











Energy generated, gross


Month Year Since


Time availability


Energy availability

[%] *) Energy utilisation

[%] *)

Month Year Month Year Month Year

OL1 Olkiluoto 1) BWR FI 910 880 484 432 112 2 945 004 279 979 721 65.04 89.37 62.85 87.77 63.13 88.35

OL2 Olkiluoto 1,4) BWR FI 910 880 378 347 351 3 015 004 269 917 726 50.81 89.90 50.58 89.81 50.75 90.45

KCB Borssele 1,4) PWR NL 512 484 499 223 019 1 671 972 173 740 769 58.20 91.41 58.22 91.42 58.23 90.16

KKB 1 Beznau 1,7) PWR CH 380 365 433 159 742 1 260 683 134 472 069 58.20 91.42 56.33 90.83 55.97 91.48

KKB 2 Beznau 6,7) PWR CH 380 365 744 282 009 1 377 536 141 753 837 100.00 100.00 100.00 100.00 99.78 100.08

KKG Gösgen 1,2,7) PWR CH 1060 1010 509 534 805 3 552 518 334 439 107 68.35 92.52 67.92 91.95 67.81 92.50

CNT-I Trillo 3) PWR ES 1066 1003 360 380 667 3 129 396 267 153 244 48.44 82.34 48.36 82.23 47.69 80.56

Dukovany B1 PWR CZ 500 473 744 366 520 1 289 586 120 934 025 100.00 72.43 99.45 71.38 98.53 71.19

Dukovany B2 PWR CZ 500 473 744 364 274 1 795 247 116 407 162 100.00 100.00 99.61 99.82 97.92 99.10

Dukovany B3 PWR CZ 500 473 660 314 737 1 731 972 115 092 529 88.71 97.68 87.87 97.37 84.61 95.61

Dukovany B4 PWR CZ 500 473 744 364 171 1 136 707 115 702 608 100.00 63.92 99.51 63.12 97.90 62.75

Temelin B1 PWR CZ 1080 1030 230 208 026 2 421 505 131 992 795 30.91 62.57 25.68 61.46 25.84 61.77

Temelin B2 PWR CZ 1080 1030 744 810 191 3 977 937 129 566 841 100.00 100.00 99.93 99.98 100.27 101.10

Doel 1 PWR BE 454 433 499 227 917 1 597 240 141 611 081 67.08 93.24 66.70 93.08 65.79 94.65

Doel 2 2) PWR BE 454 433 744 349 212 1 320 047 139 930 112 100.00 78.03 99.98 77.32 100.29 77.90

Doel 3 PWR BE 1056 1006 744 796 408 3 819 505 275 031 816 100.00 99.22 100.00 98.92 100.74 99.25

Doel 4 PWR BE 1084 1033 744 815 217 3 962 050 281 322 040 100.00 100.00 99.97 99.99 99.60 99.35

Tihange 1 PWR BE 1009 962 744 737 163 3 660 915 311 527 890 100.00 100.00 98.54 99.53 98.32 100.38

Tihange 2 PWR BE 1055 1008 395 310 332 2 621 020 268 324 837 53.02 74.46 39.44 68.46 39.44 69.04

Tihange 3 PWR BE 1089 1038 744 797 031 3 908 177 290 561 835 100.00 100.00 99.97 99.98 98.88 99.60

Plant name












Energy generated, gross


Time availability


Energy availability Energy utilisation

[%] *) [%] *)

Month Year Since Month Year Month Year Month Year


GKN-II Neckarwestheim 4) DWR 1480 1410 744 1 013 850 5 027 350 356 378 894 100.00 100.00 100.00 99.98 97.51 99.39

KBR Brokdorf DWR 1406 1335 744 1 019 287 4 967 761 376 231 090 100.00 100.00 99.95 99.96 92.37 92.45

KKE Emsland 1,2) DWR 1430 1360 348 479 085 4 474 670 373 485 371 46.83 88.98 46.20 88.79 45.80 87.90

KKI-2 Isar DWR 1344 1288 744 1 062 814 5 302 849 382 731 892 100.00 100.00 100.00 99.99 95.82 98.29

KRB C Gundremmingen SWR 1485 1410 744 999 351 4 891 476 355 369 242 100.00 100.00 100.00 99.90 99.27 99.77

KWG Grohnde DWR 1400 1310 744 1 003 789 4 078 261 402 838 610 100.00 82.37 100.00 81.99 93.79 78.32


atw Vol. 66 (2021) | Issue 5 ı September

down their fossil-fired generation. As

the sun goes down, people come home

from work and turn on air conditioning

and TVs and start using appliances

like microwaves for dinner. As

demand increases, solar disappears.

Plain and simple, demand

threatens to rise faster than the fossilfueled

system can accommodate.

The solution is to store energy for

when it’s needed most, and that’s

where advanced nuclear technologies

have a strong role to play. These

nuclear innovations must be developed

in parallel with increased

deployment of wind and solar,

building a foundation of always-on,

carbon-free energy that can also help

maintain the instantaneous balance

between supply and demand.

Four of the newest advanced

nuclear designs are being prepared to

store energy, using innovative ways to

run a nuclear reactor continuously

while varying the electricity output.

When the reactor’s production of heat

exceeds the demand for electricity, the

excess energy is stored as heat. When

demand for electricity is higher than

what the reactor is producing, the

extra heat is drawn from the storage

tank and turned into electricity.

An example of this design is

the Natrium project, a partnership

between Bill Gates’s TerraPower and

GEHitachi that is backed by the United

States Department of Energy.

Natrium is choosing among four sites

of soon-to-be-retired coal plants in

Wyoming for a plant that can vary its

output from 100 megawatts to 500


TerraPower also has a design for a

molten chloride reactor that would

store energy as heat. Moltex Energy

and Terrestrial Energy also have reactors

in design that would use a giant

tank filled with salt or rocks as a bank

for depositing or withdrawing heat.

The concept keeps the reactor running

at full output almost all the time,

while creating heat storage and saving

the energy for when it’s most valuable

and needed.

While other options exist to store

energy, advanced nuclear technologies

are critical to this effort as they

offer both an efficient and environmentally

friendly energy storage

option. When compared to batteries

for example, heat storage is cheaper

and doesn’t require scarce minerals.

Policymakers and developers are

smartly investing in new innovative

nuclear designs. Their investments

have the potential to offer tremendous

returns with new designs churning

out the reliable, carbon-free energy

necessary to reach our climate goals,

while also helping match production

with demand by efficiently storing

energy as heat.

Advanced reactors will be essential

in multiple ways to our future energy

grid, offering unique capabilities to

complement wind and solar technologies

and demonstrating vital

inno vation to match our energy needs.

| www.nei.org (211711749)

*) Net-based values

(Czech and Swiss nuclear

power plants


1) Refueling

2) Inspection

3) Repair

4) Stretch-out-operation

5) Stretch-in-operation

6) Hereof traction supply

7) Incl. steam supply

BWR: Boiling

Water Reactor

PWR: Pressurised Water


Source: VGB



Operating Results June 2021

Plant name Country Nominal











Energy generated, gross


Month Year Since


Time availability


Energy availability

[%] *) Energy utilisation

[%] *)

Month Year Month Year Month Year

OL1 Olkiluoto BWR FI 910 880 720 654 062 3 599 066 280 633 783 100.00 91.13 99.48 89.71 98.74 90.08

OL2 Olkiluoto 1) BWR FI 910 880 267 225 370 3 240 374 270 143 096 37.13 81.15 34.59 80.65 34.02 81.10

KCB Borssele 1) PWR NL 512 484 0 0 1 671 972 173 740 769 0 76.26 -900 -73 0 75.21

KKB 1 Beznau 6,7) PWR CH 380 365 720 270 721 1 531 404 134 742 790 100.00 92.84 100.00 92.35 98.92 92.72

KKB 2 Beznau 7) PWR CH 380 365 720 268 898 1 646 434 142 022 735 100.00 100.00 100.00 100.00 98.26 99.78

KKG Gösgen 1,2,7) PWR CH 1060 1010 143 120 843 3 673 361 334 559 950 100.00 93.76 16.15 79.38 15.83 79.79

CNT-I Trillo 1,2) PWR ES 1066 1003 174 154 854 3 284 250 267 308 098 24.21 72.70 19.76 71.87 19.79 70.48

Dukovany B1 PWR CZ 500 473 720 349 270 1 638 855 121 283 294 100.00 77.00 100.00 76.12 97.02 75.47

Dukovany B2 PWR CZ 500 473 720 345 231 2 140 479 116 752 393 100.00 100.00 100.00 99.85 95.90 98.57

Dukovany B3 PWR CZ 500 473 0 0 1 731 972 115 092 529 0 81.49 0 81.23 0 79.76

Dukovany B4 PWR CZ 500 473 720 353 561 1 490 268 116 056 169 100.00 69.91 99.92 69.22 98.21 68.63

Temelin B1 PWR CZ 1080 1030 720 775 720 3 197 225 132 768 515 100.00 68.78 99.91 67.83 99.57 68.04

Temelin B2 PWR CZ 1080 1030 552 581 844 4 559 781 130 148 685 76.67 96.13 74.39 95.74 74.41 96.68

Doel 1 2) PWR BE 454 433 250 102 737 1 699 977 141 713 819 34.67 83.53 30.87 82.77 30.46 84.01

Doel 2 PWR BE 454 433 720 331 796 1 651 843 140 261 908 100.00 81.67 99.96 81.07 98.45 81.31

Doel 3 PWR BE 1056 1006 720 753 303 4 572 808 275 785 119 100.00 99.35 99.01 98.93 98.53 99.13

Doel 4 PWR BE 1084 1033 720 778 772 4 740 822 282 100 811 100.00 100.00 100.00 99.99 98.29 99.18

Tihange 1 PWR BE 1009 962 720 704 797 4 365 712 312 232 687 100.00 100.00 99.91 99.59 97.08 99.84

Tihange 2 PWR BE 1055 1008 720 735 259 3 356 279 269 060 096 100.00 78.69 99.15 73.55 97.64 73.78

Tihange 3 PWR BE 1089 1038 720 761 960 4 670 136 291 323 795 100.00 100.00 99.96 99.98 97.61 99.27

Plant name












Energy generated, gross


Time availability


Energy availability Energy utilisation

[%] *) [%] *)

Month Year Since Month Year Month Year Month Year


GKN-II Neckarwestheim 1,2,4) DWR 1480 1410 256 309 100 5 336 450 356 687 994 35.56 89.32 35.56 89.30 30.48 87.97

KBR Brokdorf DWR 1406 1335 720 1 023 756 5 991 517 377 254 846 100.00 100.00 100.00 99.97 95.87 93.02

KKE Emsland DWR 1430 1360 720 992 975 5 467 645 374 478 346 100.00 90.81 100.00 90.65 98.07 89.59

KKI-2 Isar DWR 1344 1288 720 995 880 6 298 729 383 727 772 100.00 100.00 100.00 99.99 92.60 97.34

KRB C Gundremmingen SWR 1485 1410 720 932 684 5 824 160 356 301 926 100.00 100.00 98.02 99.59 95.64 99.08

KWG Grohnde DWR 1400 1310 720 967 132 5 045 393 403 805 742 100.00 85.29 99.63 84.91 93.30 80.80


atw Vol. 66 (2021) | Issue 5 ı September



US: $1.2 Trillion Infrastructure

Bill Includes Plans for New

Reactors and Credits for

Existing Plants

(nucnet) President Joe Biden’s $1.2tn

infrastructure bill, passed this week by

the Senate, lays out plans for the

development of new nuclear reactor

technology and a credit programme

for existing reactors that face closure

because of economic reasons.

The bill, which still needs approval

from the House of Representatives,

says energy secretary Jennifer Granholm

will submit a report describing

how the Department of Energy could

improve energy resilience and reduce

carbon emissions with the use of small

modular reactors and microreactors.

The report should be submitted to

the Senate’s committee on energy and

natural resources and the House of

Representatives’ committees on energy

and commerce, and science, space and

technology not later than 180 days

after the legislation becomes law.

The bill says the DOE will offer

financial and technical assistance to

entities to conduct feasibility studies

to identify suitable locations for the

deployment of SMRs, microreactors

and advanced reactors in isolated


The bill includes a proposal to

develop at least one regional clean

hydrogen hub to demonstrate the

production of clean hydrogen from

nuclear energy.

Another key element of the bill for

the nuclear industry is its call for a

credit programme for commercial

nuclear reactors. It calls on Ms

Granholm to evaluate nuclear reactors

that are projected to be permanently

shut down because of economic factors

and to allocate credits to those that


In order to qualify for credits, the

owner or operator of a nuclear plants

will need to file an application with

the DOE.

The bill says the application will

need to incorporate information

including “the average projected

annual operating loss in dollars per

megawatt-hour, inclusive of the cost of

operational and market risks, expected

to be incurred by the nuclear reactor

over the four-year period for which

credits would be allocated”. The application

should also include an estimate

of the potential incremental air pollutants

that would result if the nuclear

reactor were to cease operations.

Press reports in the US have said

the legislation will come too late to

prevent the Byron and Dresden

nuclear power plants in Illinois from

being shut down this year. Operator

Exelon said proposed Illinois legislation,

separate from the federal infrastructure

bill, that would provide state

subsidies is “the only solution that can

pass in time to provide the certainty

we need”.

Exelon, the nation’s largest operator

of nuclear plants, has filed plans to

decommission its Byron and Dresden

units, citing a lack of action from state

lawmakers on clean energy legislation

that would help save the facilities. The

company said that without a legislative

solution, these same market

inequities will also force it to close its

Braidwood and LaSalle nuclear facilities

sometime in the next few years.

The US feet of 93 nuclear plants,

which provides about 20 % of the

nation’s electricity, have been facing

revenue shortfalls because of declining

energy prices and market rules

that the nuclear industry says favour

fossil fuel plants.

The Washington-based Nuclear

Energy Institute has said a combination

of policy and economic factors

has led to the premature closure of

several highly reliable plants with

high capacity factors and relatively

low generating costs.

It said additional plants will face

the prospect of early closure unless

policies that value the benefits of

nuclear energy are put in place.


United Nations: Europe Needs

‘Consistent Policies And Clear

Market Frameworks’ For New


(nucnet) Decarbonising energy is a

significant undertaking that will

require deployment of all available

low-carbon technologies, including

nuclear power, but governments must

provide positive, long-term policy

signals for new reactor development,

according to a new technology brief

from the United Nations Economic

Commission for Europe (UNECE)*.

The brief says consistent policies

and clear market frameworks will enable

investment in new nuclear power

projects and support stable supply


In an apparent reference to

Europe’s sustainable finance taxonomy,

it says “green finance classifications

should be based on scientific

and technology-neutral methodologies”.

Multilateral banks and

international finance institutions

should consider nuclear projects as

part of their “sustainable lending activities”.

The sustainable finance taxonomy

is a package of regulations that

governs investment in activities that

the EU says are environmentally


The European commission decided

not to include nuclear energy in the

taxonomy, which entered into force

last summer, but said it would include

it under a complementary delegated

act in 2021. The act would carry the

technical screening criteria for determining

the conditions under which

nuclear could qualify as contributing

to sustainability and climate change


The commission asked the Joint

Research Centre, its scientific expert

arm, to assess nuclear power against

the taxonomy’s “do no significant

harm” criteria. When the report was

ready in April, the commission asked

two other expert groups – the Euratom

Article 31 expert group on radiation

protection and the scientific committee

on health, environmental and

emerging risks (Scheer) – to review

the JRC’s report and provide additional


The EC then said it would need to

take into account the three reports

before it makes a decision about the

inclusion of nuclear in delegated acts

in the taxonomy. Delegated acts are

legally-binding rules which will

supplement the taxonomy.

The UNECE brief calls for governments

to accelerate the development

and deployment of small modular

reactors and advanced reactor technologies,

with technical, financial and

regulatory support “essential” for the

deployment and commercialisation of

these new nuclear technologies.

International harmonisation of

licensing frameworks is also needed if

new nuclear projects are to succeed.

The policy brief also says securing

the long-term operation of existing

nuclear plants will avoid unnecessary

CO 2 emissions and decrease the costs

of Europe’s energy transition.

UNECE, set up in 1947, is one of five

regional commissions of the United

Nations. Its main aim is to promote

pan-European economic integration.

UNECE includes 56 member States in

Europe, North America and Asia.


atw Vol. 66 (2021) | Issue 5 ı September


Prize range: Spot market [USD*/lb(US) U 3O 8]


) 1

Uranium prize range: Spot market [USD*/lb(US) U 3O 8]


) 1











Yearly average prices in real USD, base: US prices (1982 to1984) *







Jan. 2009

Jan. 2010


Jan. 2011

Jan. 2012

* Actual nominal USD prices, not real prices referring to a base year. Year


Jan. 2013


Jan. 2014

Jan. 2015


Jan. 2016


Jan. 2017

Jan. 2018


Jan. 2019


Jan. 2020




* Actual nominal USD prices, not real prices referring to a base year. Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2021 * Actual nominal USD prices, not real prices referring to a base year. Year

Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2021

| Uranium spot market prices from 1980 to 2021 and from 2009 to 2021. The price range is shown.

In years with U.S. trade restrictions the unrestricted uranium spot market price is shown.

Separative work: Spot market price range [USD*/kg UTA]

Conversion: Spot conversion price range [USD*/kgU]



) 1 ) 1












Jan. 2021

Jan. 2022

Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2021


Jan. 2009

Jan. 2010

Jan. 2011

Jan. 2012

Jan. 2013

Jan. 2014

* Actual nominal USD prices, not real prices referring to a base year. Year

| Separative work and conversion market price ranges from 2009 to 2021. The price range is shown.


In December 2009 Energy Intelligence changed the method of calculation for spot market prices. The change results in virtual price leaps.

* Actual nominal USD prices, not real prices referring to a base year

Sources: Energy Intelligence, Nukem; Bilder/Figures: atw 2021












Jan. 2009

Jan. 2010

Jan. 2011

Jan. 2012

Jan. 2013

Jan. 2014

Jan. 2015

Jan. 2015

Jan. 2016

Jan. 2016

Jan. 2017

Jan. 2017

Jan. 2018

Jan. 2018

Jan. 2019

Jan. 2019

Jan. 2020

Jan. 2020

Jan. 2021

Jan. 2021

Jan. 2022

Jan. 2022

Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2021

Market data

(All information is supplied without


Nuclear Fuel Supply

Market Data

Information in current (nominal)

U.S.-$. No inflation adjustment of

prices on a base year. Separative work

data for the formerly “secondary

market”. Uranium prices [US-$/lb

U 3 O 8 ; 1 lb = 453.53 g; 1 lb U 3 O 8 =

0.385 kg U]. Conversion prices [US-$/

kg U], Separative work [US-$/SWU

(Separative work unit)].


p Uranium: 19.25–26.50

p Conversion: 4.50–6.75

p Separative work: 39.00–50.00


p Uranium: 21.75–29.20

p Conversion: 6.00–14.50

p Separative work: 34.00–42.00


p Uranium: 23.90–29.10

p Conversion: 13.50–23.00

p Separative work: 41.00–52.00


January to March 2020

p Uranium: 24.10–27.40

p Conversion: 21.50–23.50

p Separative work: 45.00–53.00

April 2020

p Uranium: 27.50–34.00

p Conversion: 21.50–23.50

p Separative work: 45.00–52.00

May 2020

p Uranium: 33.50–34.50

p Conversion: 21.50–23.50

p Separative work: 48.00–52.00

June 2020

p Uranium: 33.00–33.50

p Conversion: 21.50–23.50

p Separative work: 49.00–52.00

July 2020

p Uranium: 32.50–33.20

p Conversion: 21.50–23.50

p Separative work: 50.50–53.50

August 2020

p Uranium: 30.50–32.25

p Conversion: 21.50–23.50

p Separative work: 51.00–54.00

September 2020

p Uranium: 29.90–30.75

p Conversion: 21.00–22.00

p Separative work: 51.00–54.00

October 2020

p Uranium: 28.90–30.20

p Conversion: 21.00–22.00

p Separative work: 51.00–53.00

November 2020

p Uranium: 28.75–30.25

p Conversion: 19.00–22.00

p Separative work: 51.00–53.00

December 2020

p Uranium: 29.50–30.40

p Conversion: 19.00–22.00

p Separative work: 51.00–53.00

January 2021

p Uranium: 29.50–30.50

p Conversion: 19.00–22.00

p Separative work: 51.00–53.00

February 2021

p Uranium: 28.75–29.10

p Conversion: 20.00–22.00

p Separative work: 52.00–54.00

March 2021

p Uranium: 27.25–31.00

p Conversion: 20.00–22.00

p Separative work: 52.00–55.00

April 2021

p Uranium: 28.40–31.00

p Conversion: 19.00–21.00

p Separative work: 51.00–54.00

May 2021

p Uranium: 29.15–31.35

p Conversion: 19.50–21.50

p Separative work: 52.00–54.00

June 2021

p Uranium:31.00–32.50

p Conversion: 19.50–21.50

p Separative work: 54.00–56.00

| Source: Energy Intelligence



atw Vol. 66 (2021) | Issue 5 ı September



John Shepherd

is editor-in-chief

of the online publication

New Energy 360 &

World Battery News.


IPCC report summary:


MEPs letter to EC:


As Science Turns Up the Heat on Climate Change Sceptics,

How Long Before the Nero-like Nuclear Deniers Must Change

Their Tune?

The loss of life and catastrophic impact of the floods that swept through Europe earlier this year, coupled with the horrific

scenes of wildfires raging in southern Europe, the US and elsewhere, have been the starkest wake-up call to date of the

effects of climate change.

Climate change deniers have still been out there, a little bit

like the apocryphal account of Nero, the former emperor of

Rome, “fiddling” while the city was engulfed by a near

week-long fire.

But what cannot be denied is the science telling us that

human activities, including the generation of greenhouse

gases (GHGs), are contributing to increasing climatic


As I submitted this article to the editor, the latest report

from the UN’s Intergovernmental Panel on Climate Change

(IPCC) stated: “Climate change is intensifying the water

cycle. This brings more intense rainfall and associated

flooding, as well as more intense drought in many regions.”

The report added that emissions of GHGs from human

activities “are responsible for approximately 1.1 °C of

warming since 1850-1900”. Averaged over the next 20 years,

the IPCC’s report said global temperature is expected to

reach or exceed 1.5 °C of warming.

The report also noted that weather conducive to wildfires

could be traced to human influence and gave new estimates

of the chances of crossing the global warming level of 1.5 °C

in the next decades, finding that “unless there are immediate,

rapid and large-scale reductions in greenhouse gas

emissions, limiting warming to close to 1.5 °C or even 2 °C

will be beyond reach”.

Energy production accounts for two-thirds of total greenhouse

gas, so efforts to reduce emissions and mitigate climate

change must include this sector and nuclear power can be a

massive part of the solution – as those involved in the industry

should never tire of reminding themselves and others.

Nuclear plants produce almost no GHGs or air pollutants

during their operation. This edition of atw is focused on

uranium and the nuclear fuel cycle, so with that in mind, it’s

worth reminding ourselves that over the course of its life

cycle, nuclear produces about the same amount of carbon

dioxide-equivalent emissions per unit of electricity as wind,

and one-third of the emissions per unit of electricity when

compared with solar.

Sadly, even nuclear has an even bigger hurdle to

overcome – that most exasperating of human activity that

sometimes stands in the way of fighting climate change: a

combination of environmental and political dogma.

Let’s take Germany, where federal elections are due in

September 2021, as an example.

Long before flooding wrecked communities along the

Rhine and Ahr rivers, Annalena Baerbock, the Greens’

candidate seeking to replace outgoing chancellor Angela

Merkel, thrust the issue of climate change into the election


Baerbock told the German news magazine, Der Spiegel:

“Germany has been fortunate for decades in suffering

relatively few natural catastrophes, however, that’s meant

that the disaster protection measures haven’t been

sufficiently developed.”

I don’t know if the would-be Green chancellor was asked

about her party’s decades of opposition to nuclear energy

and whether that had had an impact on the environment,

but I’m guessing not.

So what about other potential German leaders heading to

the ballot box? German vice-chancellor and finance minister,

Olaf Scholz, the Social Democrats’ candidate to replace

Merkel, pledged a “billions-strong recovery programme” and

said he wanted to see changes to the country’s disaster

prevention plans and climate protection measures. But as I

write he too had yet to spell out the details.

Legislation that came into force in Germany in 2002

limited the operating lifetimes of German reactor units to

about 32 years. The politically-inspired move aimed to

ensure the gradual phase-out of the use of nuclear power in

the country.

Merkel, a former research scientist, said early on in her

chancellorship that she personally was against the


Meanwhile, a group of five EU Member States, led by

Germany, have written to the European Commission, asking

for nuclear energy to remain excluded from the EU

Taxonomy on Sustainable Finance – the classification system

to establish a list of environmentally-sustainable economic


The letter was signed, Nero-like, by the environment or

energy ministers of Austria, Denmark, Germany, Luxembourg

and Spain and pointed to “shortcomings” in a report

published last April by the Joint Research Centre (JRC).

The JRC, whose mission is to support EU policies with

independent evidence throughout the whole policy cycle,

had said nuclear energy did no more harm to human health

or the environment than any other power- producing

technology considered to be sustainable.

However, there were some who sought to keep the

embers of a sensible, science-based approach to environmental

economics alive. Nearly 100 members of the

European Parliament called on the European Commission to

follow the science and include nuclear under the taxonomy

classification system.

Their move was backed by Yves Desbazeille, the directorgeneral

of Foratom, the Brussels-based trade association for

the nuclear energy industry in Europe. He said EU member

states that wished to invest in low-carbon nuclear “should

not be prevented from doing so just because others are

politically opposed” to nuclear.

Amid all of this, it was ironic that Germany marked 60

years of generating electricity from nuclear power, after the

first power supply to the grid came from the Kahl

experimental boiling water reactor plant in June 1961. This

was the first time that electricity from nuclear energy had

been fed in and used in Germany.

Nuclear’s detractors might, if pushed, offer a grudging

acceptance to the impact of nuclear in tackling emissions,

but they would probably go on to argue that switching the

entire world’s electricity production to nuclear would still

not solve the problem of GHGs. Given that electricity

production is only one of many human activities that release

GHGs, that’s likely true.

However, the nuclear industry itself would be the first

to say its technology is not the ‘silver bullet’ needed to slay

the monstrosities wrought by climate change. Nuclear, by

all sensible accounts, should be allowed to form part of

the solution. The sooner those who seek to lead have the

courage to accept that essential truth the better for the

whole planet.

Nuclear Today

As Science Turns Up the Heat on Climate Change Sceptics, How Long Before the Nero-like Nuclear Deniers Must Change Their Tune?

ı John Shepherd



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