atw International Journal for Nuclear Power

nucmag.com

2020

ISSN · 1431-5254

24.– €

Nuclear Rockets

for Interplanetary

Space Missions

Excursus to the World

of Nuclear Medicine

Radiation in Art and

Cultural Heritage

Kommunikation und

Training für Kerntechnik

Suchen Sie die passende Weiter bildungs maßnahme im Bereich Kerntechnik?

Wählen Sie aus folgenden Themen: Dozent/in Termin/e Ort

3 Atom-, Vertrags- und Exportrecht

Atomrecht – Das Recht der radioaktiven Reststoffe und Abfälle RA Dr. Christian Raetzke 20.10.2020 Berlin

Export kerntechnischer Produkte und Dienstleistungen –

Chanchen und Regularien

Atomrecht – Ihr Weg durch Genehmigungs- und

Aufsichtsverfahren

RA Kay Höft M.A. (BWL) 17.06.2020 Berlin

RA Dr. Christian Raetzke 25.06.2020 Berlin

Atomrecht – Was Sie wissen müssen

3 Kommunikation und Politik

RA Dr. Christian Raetzke

Akos Frank LL. M.

11.11.2020 Berlin

Public Hearing Workshop –

Öffentliche Anhörungen erfolgreich meistern

Dr. Nikolai A. Behr 10.11. - 11.11.2020 Berlin

3 Rückbau und Strahlenschutz

In Kooperation mit dem TÜV SÜD Energietechnik GmbH Baden-Württemberg:

3 Nuclear English

Das Strahlenschutzrecht und

seine praktische Umsetzung

Stilllegung und Rückbau in Recht und Praxis

Dr. Maria Poetsch

RA Dr. Christian Raetzke

Dr. Stefan Kirsch

RA Dr. Christian Raetzke

16.06. - 17.06.2020

29.10. - 30.10.2020

Berlin

23.09. - 24.09.2020 Berlin

English for the Nuclear Industry Angela Lloyd 07.10. - 08.10.2020 Berlin

3 Wissenstransfer und Veränderungsmanagement

Erfolgreicher Wissenstransfer in der Kerntechnik –

Methoden und praktische Anwendung

Dr. Tanja-Vera Herking

Dr. Christien Zedler

05.10. - 06.10.2020 Berlin

Haben wir Ihr Interesse geweckt? 3 Rufen Sie uns an: +49 30 498555-30

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atw Vol. 65 (2020) | Issue 4 ı April

Space: Final Frontier – Always Nuclear

Dear reader, In these days, when our society is confronted globally with the challenges and the management of the

Corona pandemic, the focus of this editorial should not be on controversial issues concerning the earth, but rather look

beyond into the vastness of space.

183

If mankind embarks on a journey into space or sends

satellites on their way into the cosmos, the question of a

suitable energy supply arises – the effort to navigate and

leave the Earth's gravitational field is left out of the equation

– which makes a space mission possible. If astronauts are

involved, sufficient heat, cooling and breathing air must be

provided, among other things. If they are unmanned

satellites, the only essential thing is to provide energy for the

technical, i.e. electrical, systems.

There are basically three forms of nuclear energy

available today for space missions:

The first is indirect use. The nuclear fusion reactor, the

sun, provides the radiation energy – light, which is converted

into electrical energy in photovoltaic cells. The basic

principles of photovoltaics have been known for a very long

time. The basis, the photoelectric effect, was discovered in

1839. However, the technical breakthrough came more than

100 years later, when the U.S. satellite Vanguard I was

equipped with photovoltaic cells in addition to a fuel cell in

1958. Among other things, these made it possible to operate

the satellite for almost six years.

The second form is the installation of a nuclear fission

reactor:

The first nuclear reactor for energy supply was launched

into orbit on 4 April, 1965 by the U.S. Air Force with an Atlas

launcher and the Snapshot technology satellite. The aim of

the mission was, on the one hand, to test a nuclear reactor in

a satellite and, on the other, to test the function of an ion

engine. The reactor was derived from the SNAP – System

for Auxiliary Power Program of the U.S. Atomic Energy

Commission. The actual reactor core had a weight of 290 kg,

a volume of about 16 l and gave off a thermal output of

about 30 kW during operation. The chain reaction was

controlled by four externally arranged, semi-cylindrical

neutron reflectors made of beryllium. The heat was removed

from the reactor by an alloy of sodium-potassium (NaK)

and converted into electric current in thermocouples

with a maximum output power of 0.5 kilowatts (kW). The

temperature difference between the NaK coolant and the

surrounding space was the driving force. Due to a malfunction

in the satellite electronics, the mission was aborted after

43 days and the reactor was shut down. While for the USA

the energy supply with nuclear reactors in space did not play

a role in later years, the Soviet Union had launched almost

40 Radar Ocean Reconnaissance Satellites into orbit, which

were equipped with uranium reactors of the designation

BES-5 and Topas. The military satellites, also known as

Cosmos, were able to monitor ship movements with active

radar from low orbit and therefore had to be supplied with a

powerful energy source, i.e. a nuclear reactor, due to their

high energy requirements.

In early March 2020, there was a surprising success story

from space, from Mars. The Rover Curiosity, which has been

active on our neighbouring planet for more than seven

years, provided the largest panorama to date with a

resolution of 1.8 gigapixels – current digital cameras provide

single images with a range of around 25 megapixels. The

image was assembled from more than 1000 single images

and shows the surroundings on the slope of the mountain

Aeolis Mons. The images were taken between November 24

and December 1, 2019, when no further experiments or

activities were scheduled for Curiosity. Curiosity had landed

on Mars in 2012. The search for traces of earlier life and

basic environmental conditions on Mars are among the

mission's objectives. The energy supply for the rover is

provided by radionuclide batteries which, unlike in previous

missions, are independent of weather conditions and also

ensure constant, stable thermal conditions for the rover's

systems. Radionuclide batteries are the third option for

energy supply in space.

The Curiosity mission is based on initial considerations in

2003 and a National Academy document entitled “New

Frontiers in the Solar System: An Integrated Exploration

Strategy”. The mission was launched on 26 November 2011

on board an Atlas V rocket. Nine months later, the rover

landed on Mars in August 2012 and started its experiments.

Another important aspect of the rover is its mobility. This

means that it is not tied to its landing point for carrying out

experiments, but can travel to points that seem particularly

suitable for investigations. By the beginning of 2020,

Curiosity was thus able to cover a distance of around 22 km

and to convince with impressive photos of the surface of

Mars in particular. The Curiosity mission is also a

technological success. The mission was originally planned

for two years, but was extended until today – seven and a

half years on Mars – due to the reliability of the rover's

technology, including the energy supply, and the scientific

results.

Radionuclide batteries, or RTGs (radioisotope thermoelectric

generators) for short, are a very reliable and compact

option for energy supply. The basis is the conversion of

thermal energy from the decay of radio active isotopes in a

thermoelectric element into electrical energy. Since the

half-life period can be used to adjust the temporal availability

of the heat source and RTGs do not need any moving

parts, they are very reliable. Although the mass-to-power

ratio is worse than that of nuclear reactors, their simple

design is an advantage for missions without the possibility of

on-site maintenance.

The first known RTGs for space missions were tested

under the NASA SNAP program in 1958. In 1961, SNAP-3

was the first application in space. NASA has documented

27 missions with RTGs, including one in the Apollo program,

which used nuclear energy to power a measuring instrument

on the moon. Furthermore the use in space missions

of ESA, China and Russia or the former Soviet Union is

known but not documented in detail.

Two other missions, Voyager 1 and 2 probes, have also

brought terrestrial nuclear energy technology outside the

solar system. In 2012 and 2018, respectively, the spacecraft

launched in 1977 left our closer space environment. These

missions were originally planned for four years; the power

supply was designed from the outset on the basis of RTGs, as

the power of photovoltaic cells beyond the orbit of Mars is

not sufficient and, in addition, they would degrade too

quickly in the radiation belt that would then follow.

It remains interesting with nuclear energy in space – let's

observe this with common sense from Earth and stay health,

Yours

Christopher

Weßelmann

– Editor in Chief –

EDITORIAL

Editorial

Space: Final Frontier – Always Nuclear

atw Vol. 65 (2020) | Issue 4 ı April

Der Weltraum: unendliche Weiten – und Kernenergie überall

184

Liebe Leserin, lieber Leser, in diesen Tagen, in denen unsere Gesellschaft global mit den Herausforderungen und der

Bewältigung der Corona-Pandemie konfrontiert wird, soll der Blick des Editorials nicht auf strittige irdische Themen fallen,

sondern darüber hinaus in die Weiten des Weltalls blicken.

EDITORIAL

Christopher

Weßelmann

– Chefredakteur –

Begibt sich der Mensch auf eine Reise in den Weltraum oder

schickt er Raumsonden auf ihren Weg in den Kosmos, stellt

sich auch hier die Frage nach einer geeigneten Energieversorgung

– der Aufwand zum Antrieb und zum Verlassen des

Erdgravitationsfeldes sei hier außen vor gelassen – , die eine

Raummission erst möglich macht. Sind Raumfahrerinnen und

Raumfahrer mit von der Partie, muss unter anderem für

ausreichend Wärme, Kühlung und Atemluft gesorgt werden,

sind es unbemannte Flugkörper, ist wesentlich nur für die

Energieversorgung der technischen, also elektrischen, Systeme

zu sorgen.

Grundsätzlich bieten sich heute drei Formen der Kernenergie

an:

Als erstes die indirekte Nutzung. Der Kernfusionsreaktor

Sonne liefert die Strahlungsenergie – Licht, die in Photovoltaikzellen

in elektrische Energie umgewandelt wird. Die

Grundlagen der Photovoltaik waren dabei schon sehr lange

bekannt. Die Grundlage, der Photoelektrische Effekt wurde

1839 entdeckt. Der technische Durchbruch gelangt allerdings

erst mehr als 100 Jahre später, als 1958 der U.S. Satellit

Vanguard I neben einer Brennstoffzelle mit Photovoltaikzellen

ausgerüstet wurde. Unter anderem diese ermöglichten

einen Betrieb des Satelliten für fast sechs Jahre.

Als zweites der Einbau eines Kernreaktors:

Der erste Kernreaktor zur Energieversorgung wurde am

4. April 1965 von der U.S. Air Force mit einer Atlas Trägerrakete

und dem Snapshot Technologiesatellit in eine

Erdumlaufbahn gestartet. Ziel der Mission war einerseits die

Erprobung eines Kernreaktors in einem Satelliten und zum

anderen die Funktion eines Ionentriebwerks. Der Reaktor

entstammte dem SNAP – System for Auxiliary Power Program

der U.S. Atomic Energy Commission. Der eigentliche Reaktorkern

hatte ein Gewicht von 290 kg, ein Volumen von etwa 16 l

und gab im Betrieb eine thermische Leistung von ca. 30 kW

ab. Die Regelung der Kettenreaktion erfolgte über vier außen

angeordnete, halbzylinderförmige Neutronenreflektoren aus

Beryllium. Die Wärme wurde von einer Legierung aus

Natrium- Kalium (NaK) aus dem Reaktor abgeführt und in

Thermoelementen mit einer maximalen Ausgangleistung von

0,5 Kilowatt (kW) in elektrischen Strom umgewandelt. Die

Temperaturdifferenz zwischen NaK-Kühlmittel und dem

umgebenden Weltraum war dabei treibende Kraft. Aufgrund

einer Fehlfunktion in der Satellitenelektronik wurde die

Mission nach 43 Tagen abgebrochen und der Reaktor abgeschaltet.

Während für die USA die Energieversorgung mit

Kernreaktoren im Weltraum in späteren Jahren keine Rolle

mehr spielte, hatte die Sowjetunion fast 40 Radar Ocean

Reconnaissance Satellites in den Orbit geschossen, die mit

Uran-Reaktoren der Bezeichnung BES-5 und Topas ausgerüstet

waren. Die auch als Kosmos bekannten Militärsatteliten

konnten Schiffsbewegungen mit aktivem Radar aus niedriger

Umlaufbahn überwachen und mussten von daher aufgrund

ihres hohen Energiebedarfs mit einer leistungsfähigen

Energie quelle versorgt werden, also einem Kernreaktor.

Anfang März 2020 gab es eine überraschende Erfolgsmeldung

aus dem Weltraum, vom Mars. Der seit mehr als

sieben Jahren auf unserm Nachbarplaneten aktive Rover

Curiosity lieferte das bislang größte Panorama mit

1,8 Gigapixel Auflösung – aktuelle Digitalkameras liefern Einzelbilder

mit einer Auflösung von ca. 25 Megapixeln. Das Bild

wurde aus mehr als 1000 Einzelbildern zusammengesetzt und

zeigt die Umgebung am Hang des Bergs Aeolis Mons. Aufgenommen

wurden diese zwischen dem 24. November und

1. Dezember 2019, als weitere Experimente bzw. Aktivitäten

für Curiosity nicht anstanden. Curiosity war 2012 auf dem

Mars gelandet. Die Suche nach Spuren früheren Lebens und

grundlegenden Umgebungsbedingungen auf dem Mars sind

unter anderem Gegenstand der Mission. Die Energieversorgung

des Rovers wird von Radionuklidbatterien sicher

gestellt, die, anders als bei früheren Missionen, wetterunabhängig

sind und zudem konstante, stabile thermische

Bedingungen für die Systeme des Rovers gewährleisten.

Radio nuklidbatterien sind die dritte Option zur Energieversorgung

im Weltraum.

Die Curiosity-Mission geht zurück auf erste Überlegungen

im Jahr 2003 und ein Dokument der National Academie unter

dem Titel „New Frontiers in the Solar System: An Integrated

Exploration Strategy“. Am 26. November 2011 startete die

Mission an Bord einer Atlas-V-Trägerrakete. Neun Monate

später landete der Rover im August 2012 auf dem Mars und

begann mit seinen Experimenten. Wichtig für den Rover ist

auch seine Beweglichkeit. Das heißt, er ist für die Durchführung

von Experimenten nicht an seinen Landepunkt

gebunden, sondern kann zu Punkten fahren, die für Untersuchungen

als besonders geeignet erscheinen. Bis Anfang

2020 konnte Curiosity so rund 22 km zurück legen und

insbesondere mit beeindrucken Fotos der Marsoberfläche

begeistern. Die Curiosity- Mission ist zudem technologisch ein

Erfolg. Denn ursprünglich war die Mission für zwei Jahre

vorgesehen, wurde aber aufgrund der Verlässlichkeit der

Technik des Rovers, inklusive Energieversorgung, sowie der

wissenschaftlichen Ergebnisse bis heute verlängert – siebeneinhalb

Jahre auf dem Mars.

Radionuklidbatterien, kurz RTG (radioisotope thermoelectric

generators) sind eine sehr zuverlässige und kompakte

Option für die Energieversorgung. Grundlage ist die Umwandlung

thermischer Energie aus dem Zerfall radioaktiver

Isotope in einem thermoelektrischen Element in elektrische

Energie. Da über die Halbwertzeit die zeitliche Verfügbarkeit

der Wärmequelle eingestellt werden kann und RTGs keine

beweglichen Teile benötigen, sind diese sehr zuverlässig. Das

Masse-Leistungs-Verhältnis im Vergleich zu Kernreaktoren ist

zwar schlechter, bei Missionen ohne die Möglichkeit eines

Eingriffs Vor-Ort spricht dann aber ihr einfacher Aufbau für

sie.

Die ersten bekannten RTGs für Raumfahrtmissionen

wurden im Rahmen des NASA SNAP-Programms 1958 getestet.

1961 erfolgte mit SNAP-3 die erste Anwendung im Weltraum.

Von der NASA sind 27 Missionen mit RTGs dokumentiert,

davon auch eine im Rahmen des Apollo-Programms, die die

Energieversorgung mit Kernenergie eines Messgerätes auf

dem Mond sicher stellte. Weiterhin ist der Einsatz in

Weltraummissionen der ESA, Chinas und Russlands bzw. der

früheren Sowjetunion bekannt, aber nicht im Detail dokumentiert.

Zwei weitere Missionen, die Voyager 1 und 2 Sonden

haben zudem die terrestrische Kernenergietechnologie außerhalb

des Sonnensystems gebracht. 2012 beziehungsweise

2018 verließen die 1977 gestarteten Raumflugkörper unsere

nähere Raumumgebung. Diese Missionen waren ursprünglich

für vier Jahre projektiert; die Stromversorgung war von

vornherein auf Basis von RTGs konzipiert, da die Leistung

von Photovoltaikzellen jenseits der Umlaufbahn des Mars

nicht mehr ausreicht und diese zudem im dann folgenden

Strahlungs gürtel zu schnell degradieren würden.

Es bleibt interessant mit der Kernenergie im Weltraum –

beobachten wir dies mit Verstand von der Erde aus und

bleiben Sie gesund, Ihr

Editorial

Space: Final Frontier – Always Nuclear

atw Vol. 65 (2020) | Issue 4 ı April

Did you know...?

Wake Effect Constraints on the Build-up of Offshore Wind Capacity

in the German North Sea

The recent study “Making the Most of Offshore Wind – Re-Evaluating

the Potential of Offshore Wind in the German North Sea” comissioned

and published by the German think tank Agora Energiewende and

issued by Technical University of Denmark, Department of Wind

Energy DTU Wind Energy and Max Planck Institute for Biogeochemistry,

Biospheric Theory and Modeling gives an anlysis of the

wake effect on a regional scale with respect to the expansion of

offshore wind energy in the German part of the north sea. Taking

account of the capacity requirements of European and German

decarbonization scenarios (see graphs below) the study concludes

that the wake effect could have a significant impact on the capacity

factor of wind turbines in the German Bight and needs to be considered

for future planning.

The wake effect is more important for wind energy offshore than

onshore because the densiy of prospective installed capacity is much

higher (10 MW/km² offshore vs below 0.5 MW/km² for German

onshore in average) and because stronger air turbulence over land

leads to a better recovery of energy in the air flow. In comparing the

scenario of 28 GW installed capacity on 2.800 km² in the German

Bight with 72 GW on 7.200 km² the study concludes that the capacity

factor with 28 GW will remain about the same 41 per cent as

today with 8 GW installed capacity, but that the expansion

to 72 GW in the same region would reduce the over all capacity

factor to some 35 per cent. The additional 44 GW capacity

thus would add only 120 TWh to the 100 TWh produced by 28 GW

installed capacity instead of some 160 TWh as would be expected

with a constant capacity factor. The authors of the study then propose

to extend the installation of additional capacity over a larger area

in cooperation with Germany's neighbours. Furthermor they suggest

to investigate the regional aspect of the wake effect for onshore

wind turbine deployment too, as well as the possible effects of

offshore expansion on the capacity factors of onshore wind turbines

in general.

For further details

please contact:

Nicolas Wendler

KernD

Robert-Koch-Platz 4

10115 Berlin

Germany

E-mail: presse@

KernD.de

www.KernD.de

DID YOU EDITORIAL KNOW...? 185

Offshore wind capacity assumed in EU climate target scenarios for 2050 in GW

1,000

800

500

specifically dedicated

to renewable hydrogen

production

600

400

396

451

510

200

1.5LIFE

1.5TECH

Optimized Gas

EC (2018c),

Navigant (2019)

Ranges of necessary wind power generation by 2050 in 95% decarbonization scenarios for Germany

in TWh

2019 2050

700

750

600

500

400

470

520

300

200

100

126

Wind Onshore

+ Offshore

Wind Onshore

+ Offshore

220

Onshore

180

280

Offshore

Acatech et al. (2017),

Agora Energiewende

(2020), BDI (2018),

BMU (2015) MWV

(2018); figures are

rounded;

Acatech et al. models

a 90% GHG emission

reduction by 2050

Did you know...?

atw Vol. 65 (2020) | Issue 4 ı April

186

Issue 4 | 2020

April

CONTENTS

Contents

Space: Final frontier – always nuclear E/G 183

Inside Nuclear with NucNet

Generation IV | The Key Challenges in the Race

for Commercialization 188

Calendar 190

Feature | Research and Innovation

Nuclear Rockets for Interplanetary Space Missions 191

Serial | Major Trends in Energy Policy and Nuclear Power

Research in Support of European Radio isotope Power

System Development at the European Commission’s Joint

Research Centre in Karlsruhe 198

Spotlight on Nuclear Law

The long path to final storage G 206

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities –

A Legal Inventory G 207

Environment and Safety

Excursus to the World of Nuclear Medicine 217

Research and Innovation

Radiation in Art and Cultural Heritage 225

Studies on the Interaction of Plant Cells with U(VI)

and Eu(III) and on Stress- induced Metabolite Release 230

KTG Inside 234

Cover:

Curiosity at Glen Etive

Courtesy of NASA

News 235

Nuclear Today

Cards Still Stacked Against Nuclear in Green Investment Deal 238

E/G

= German

= English/German

Imprint 216

Contents

atw Vol. 65 (2020) | Issue 4 ı April

187

Feature

Research and Innovation

CONTENTS

191 Nuclear Rockets

for Interplanetary Space Missions

Dr. William Emrich

Serial | Major Trends in Energy Policy and Nuclear Power

198 Research in Support of European Radio isotope Power System

Development at the European Commission’s Joint Research Centre

in Karlsruhe

Daniel Freis, Jean-François Vigier, Karin Popa, Rudy J.M. Konings

Energy Policy, Economy and Law

207 Disposal of Dismantling Materials from Nuclear Facilities –

A Legal Inventory

Die Entsorgung von Rückbaumassen aus kerntechnischen Anlagen –

Eine rechtliche Bestandsaufnahme

RA Dr. Christian Raetzke

Environment and Safety

217 Excursus to the World of Nuclear Medicine

Andreas Schmidt, Klaus Tatsch, Beate Pfeiffer, Verena Störzbach and Maximilian Kauth

Research and Innovation

225 Radiation in Art and Cultural Heritage

Frank Meissner and Andrea Denker

230 Studies on the Interaction of Plant Cells with U(VI) and Eu(III)

and on Stress- induced Metabolite Release

Jenny Jessat, Susanne Sachs, Robin Steudtner and Thorsten Stumpf

Contents

atw Vol. 65 (2020) | Issue 4 ı April

188

Generation IV | The Key Challenges

in the Race for Commercialization

INSIDE NUCLEAR WITH NUCNET

Designers of new nuclear reactors need to find the right funding model and bridge the gap

between concept and prototype.

The problem for developers of Generation IV nuclear

power plants is that it is too early in the development

process for investors and potential customers to bet

significant money on the winners from an increasingly

crowded field. A working prototype would give developers

a reactor model they could sell to customers. As yet, no one

has got that far.

New patterns of investment could help. Public-private

partnerships for reactor development, of the type formed

by NuScale and the Bill Gates-backed TerraPower with the

US Department of Energy, are creating opportunities for

entrepreneurial developers who can harness the knowhow

and get access to funds.

One revenue model that holds promise for developers

of small modular reactors (defined by the International

Atomic Energy Agency as units with electrical power

ratings of less than 300 MW) is to offer heat as the primary

output of their plants. Heat can be used to generate

electricity, but it can also be used for process heat for

industry, especially for manufacturing chemicals, the

production of hydrogen, and desalinisation. The combination

of revenues from these heat streams could

expand the business case for advanced reactors.

US think-tank Third Way says companies investing in

Generation IV technologies are being built and funded

because the innovators and investors see profit in creating

an answer to the global energy paradox – there are

1.3 billion people in the world without access to reliable

electricity. “Advanced nuclear can provide that electricity

while cutting global carbon emissions,” the think-tank

said.

Generation IV reactors offer the promise of improved

safety, efficiency, and lower costs. A 2017 study by Energy

Innovation Reform Project put the average levelised cost of

electricity (LCOE) at $ 60/MWh, or 39 % lower than the

$ 99/MWh expected by the US Energy Information Agency

for pressurised-water reactor nuclear plants entering

service in the early 2020s. The LCOE is the long-term price

at which the electricity produced by a nuclear plant will

have to be sold at for the investor to cover all their costs

including a profit.

There are other advantages that could be unlocked

by the development of Generation IV plants. Up-front

capital is less than for conventional reactors and lead times

are shorter. The proliferation risk is lower because used

nuclear fuel can be used. Some models offer the possibility

of burning actinides to further reduce waste and of being

able to „breed more fuel“ than they consume. Many can

be factory-manufactured and transported to isolated,

energy-hungry areas on the back of vehicles.

The problem remains that Generation IV plants still

require substantial R&D effort, preventing their commercial

adoption in the short term.

In the US and Canada more than 50 companies

representing more than $ 1 bn in investor money, are

pursuing technical innovations in nuclear energy. They

include big-name projects like TerraPower and small

startups including California-based Oklo, which recently

received a site use permit to build a demonstration Aurora

energy plant – comprising a small reactor with integrated

solar panels – on the Idaho National Laboratory site.

There are significant differences in the timelines and

prospects for success between developers of SMRs,

depending on the type of technology they are pursuing.

Plants based on established light-water reactor technologies,

which have been in use since the 1950s, are inevitably

closer to fruition than plants based on fast neutron reactors

that do not use water as a moderator or coolant.

Potential new coolants for Generation IV plants include

liquid metal, high temperature gases, and molten salt.

Third Way says nuclear reactors using these coolants can

be even safer than most light-water reactors. The higher

operating temperatures of coolants like helium, liquid

metals, and molten salts more readily lend themselves to

industrial applications requiring high temperature process

heat – exactly the kind of applications that would add

value to the business model.

Another major focus is developing thorium-based,

molten- salt reactors – which scientists hope can be

developed to help meet the world’s growing need for

energy without contributing to global warming.

These reactors are powered by controlled fission

reactions in the same way as conventional uranium

reactors. However, the technology could prove to be

cheaper and cleaner, while the use of thorium – which is

less radioactive than uranium – may generate less waste.

India has a three-stage programme to develop thorium

fueled reactors. The country plans to use advanced

heavy-water reactors fueled with U-233 obtained from the

irradiation of thorium in PHWRs and fast reactors.

Replacing water as a coolant with liquid molten salt

could tap more of the energy available in radioactive

materials and reduce the risk of a meltdown by slowing the

nuclear reactions automatically if they get too hot.

The South China Morning Post reported that Xu

Hongjie, director of China’s molten-salt program, said

China had mastered the technology in laboratories and

planned to put it into commercial use by 2030 – before

anyone else did so. The newspaper said China has invested

about 2 billion yuan ($ 300 m) over the past few years in

molten salt research and development, but building the

plants will require tens of billions more.

A first objective for China is reported to be the design

and development of a first-of-a-kind 100 MW thorium

molten salt reactor in 2020 in the city of Wuwei in Gansu

province. Commercial development is targeted for the

early 2030s.

Another aspect of the R&D effort is that developers

need places to test their technologies, develop materials,

and new types of reactor fuel. Public-private partnerships

with government agencies, labs, private companies, and

non-profit R&D centres are vital.

A number of public-private partnerships have made

progress. NuScale’s cost-sharing agreement with the

Inside Nuclear with NucNet

Generation IV | The Key Challenges in the Race for Commercialization

atw Vol. 65 (2020) | Issue 4 ı April

DOE covers design and licensing work for its 60-MW-SMR.

TerraPower has a $ 60 m grant from the DOE for its work

with Southern, a nuclear utility, and Oak Ridge National

Laboratory on its molten chloride salt reactor. Southern

and other partners, such as the Electric Power Research

Institute, add their resources, including funds and

expertise, to the effort.

The most significant international endeavor to make

progress with Generation IV technology is the Generation

IV International Forum (GIF), a cooperative effort set up

by nine founding-member countries (it now has 14

member countries) in 2000 to carry out the R&D needed to

establish the feasibility and performance capabilities of

Generation IV nuclear energy systems. The forum aims to

pool resources, allowing scientists to develop safer and

cheaper next-generation systems. It wants to commercially

deploy Generation IV systems by 2040.

The six technologies undergoing R&D are the gascooled

fast reactor, lead-cooled fast reactor, molten salt

reactor (MSR), supercritical water-cooled reactor, sodiumcooled

fast reactor (SCFR) and very high-temperature

reactor (VHTR).

Of the six, three have attracted most attention from

entrepreneurial developers: the MSR, SCFR, VHTR

designs. US national labs have rated these three designs as

having the greatest likelihood of success in the next

decade. Yet the challenges they face are enormous.

No one has ever built a commercial scale unit for any of

these designs and put the unit into revenue service for a

nuclear utility. The capital and operational costs to build

and operate a first-of-a-kind (FOAK) unit are still in a

process of discovery. The forum itself has acknowledged

that for real long-term progress to be made in Generation

IV development, advanced research facilities need to be

built, the industry must become more involved and the

“workforce of the future” should be developed.

Regulation is another obstacle. Regulatory agencies

have never assessed Generation IV reactors and the

preparations for doing so are costly and time-consuming.

Plans by the Canadian Nuclear Safety Commission and the

US Nuclear Regulatory Commission to cooperate to speed

up design reviews are a step in the right direction. Two

companies – Terrestrial Energy, a developer of an MSR,

and NuScale, which is developing an SMR based on LWR

design principles – have so far signed up for the design

review process.

The two biggest challenges remain getting through the

licensing process and convincing a nuclear utility, based on

real experience with prototypes, that an advanced design

can be built on time, within budget, and operated at a

profit.

For this to happen, a business model that includes heat

output could be crucial.

What next for Generation IV?

The nuclear industry sees a number of key steps governments

can take to speed up Generation IV deployment.

Some governments – notably the US and China – are

already making commitments of this sort.

p Fund and support test environments for MSR, SCFR,

VHTR;

p Offer cost-sharing grants to cover design, testing and

regulatory reviews.

p Legislate to introduce power purchase agreements,

which are a key instrument of project financing.

p Offer loan guarantees for construction and tax credits

for the first years of electricity production.

p Streamline the licensing framework for design review

and approval of construction.

p Support R&D for advanced fuels and financial incentives

to companies to start manufacturing them.

Author

NucNet

The Independent Global Nuclear News Agency

Editors responsible for this story:

Dan Yurman & David Dalton

Avenue des Arts 56 2/C

1000 Bruxelles, Belgium

www.nucnet.org

INSIDE NUCLEAR WITH NUCNET 189

Inside Nuclear with NucNet

Generation IV | The Key Challenges in the Race for Commercialization

atw Vol. 65 (2020) | Issue 4 ı April

190

Calendar

2020

This is not a full list.

Dates are subject to change. Please check the listed websites for updates.

CALENDAR

18.06.2020

NDA Group Supply Chain Event. Telford,

Shropshire, Cvent, www.web-eur.cvent.com

23.06. – 25.06.2020

World Nuclear Exhibition 2020. Paris Nord

Villepinte, France, Gifen,

www.world-nuclear-exhibition.com

28.09. – 02.10.2020

Jahrestagung 2020 – Fachverband Strahlenschutz

und Entsorgung. Aachen, Germany, Fachverband

für Strahlenschutz, www.fs-ev.org

30.09. – 03.10.2020

Nuclear Energy: Challenges and Prospects. Sochi,

Russia, Pocatom, www.nsconf2020.ru

05.05. – 06.05.2020

KERNTECHNIK 2020.

Berlin, Germany, KernD and KTG,

www.kerntechnik.com

10.05. – 15.05.2020

ICG-EAC Annual Meeting 2020. Helsinki, Finland,

ICG-EAC, www.icg-eac.org

11.05. – 15.05.2020

International Conference on Operational Safety

of Nuclear Power Plants. Beijing, China, IAEA,

www.iaea.org

11.05. – 15.05.2020

Fusion Energy Conference Programme

Committee Meeting. Vienna, Austria, IAEA,

www.iaea.org

18.05. – 22.05.2020

SNA+MC2020 – Joint International Conference on

Supercomputing in Nuclear Applications + Monte

Carlo 2020, Makuhari Messe. Chiba, Japan, Atomic

Energy Society of Japan, www.snamc2020.jpn.org

20.05. – 22.05.2020

Nuclear Energy Assembly. Washington, D.C., USA,

NEI, www.nei.org

31.05. – 03.06.2020

13 th International Conference of the Croatian

Nuclear Society. Zadar, Croatia, Croatian Nuclear

Society, www.nuclear-option.org

08.06. – 12.06.2020

20 th WCNDT – World Conference on

Non-Destructive Testing. Seoul, Korea, EPRI,

www.wcndt2020.com

10.06. – 12.06.2020

Innovation for the Future of Nuclear Energy –

A Global Forum. Gyeongju, South Korea,

www.globalnuclearinnovation.com

14.06. – 17.06.2020

The Society for Risk Analysis – European

Conference. Espoo, Finland, Aalto University,

www.blogs.aalto.fi

15.06. – 19.06.2020

International Conference on Nuclear Knowledge

Management and Human Resources Development:

Challenges and Opportunities. Moscow,

Russian Federation, IAEA, www.iaea.org

15.06. – 20.07.2020

WNU Summer Institute 2020. Japan, World Nuclear

University, www.world-nuclear-university.org

25.06. – 26.06.2020

NuclearEurope 2020 – Nuclear for a sustainable

future. Paris, France, Foratom,

www.events.foratom.org

13.07. – 16.07.2020

46 th NITSL Conference - Fusing Power & People.

Baltimore, MD, USA, Aalto University, www.nitsl.org

02.08. – 06.08.2020

ICONE 28 – 28 th International Conference on

Nuclear Engineering. Disneyland Hotel, Anaheim,

CA, ASME, www.event.asme.org

26.08.-04.09.2020

The Frédéric Joliot/Otto Hahn Summer School

on Nuclear Reactors “Physics, Fuels and Systems”.

Aix-en-Provence, France, CEA & KIT, www.fjohss.eu

01.09. – 04.09.2020

IGORR – Standard Cooperation Event in the International

Group on Research Reactors Conference.

Kazan, Russian Federation, IAEA, www.iaea.org

07.09. – 10.09.2020

International Forum on Enhancing a Sustainable

Nuclear Supply Chain. Helsinki, Finland, Foratom,

www.events.foratom.org

09.09. – 10.09.2020

VGB Congress 2020 – 100 Years VGB. Essen,

Germany, VGB PowerTech e.V., www.vgb.org

09.09. – 11.09.2020

World Nuclear Association Symposium 2020.

London, United Kingdom, WNA World Nuclear

Association, www.world-nuclear.org

16.09. – 18.09.2020

3 rd International Conference on Concrete

Sustainability. Prague, Czech Republic, fib,

www.fibiccs.org

16.09. – 18.09.2020

International Nuclear Reactor Materials

Reliability Conference and Exhibition.

New Orleans, Louisiana, USA, EPRI, www.snetp.eu

21.09.-25.09.2020

64 th IAEA General Conference. Vienna, Austria, International

Atomic Energy Agency IAEA,

www.iaea.org

28.09. – 01.10.2020

NPC 2020 International Conference on Nuclear

Plant Chemistry. Antibes, France, SFEN Société

Française d’Energie Nucléaire,

www.sfen-npc2020.org

postponed to 11.10. – 17.10.2020

BEPU2020– Best Estimate Plus Uncertainty International

Conference, Giardini Naxos. Sicily, Italy,

NINE, www.nineeng.com

12.10. – 17.10.2020

FEC 2020 – 28 th IAEA Fusion Energy Conference.

Nice, France, IAEA, www.iaea.org

19.10. – 23.10.2020

International Conference on the Management

of Naturally Occurring Radioactive Materials

(NORM) in Industry. Vienna, Austria, IAEA,

www.iaea.org

26.10. – 30.10.2020

NuMat 2020 – 6 th Nuclear Materials Conference.

Gent, Belgium, IAEA, www.iaea.org

27.10. – 29.10.2020

enlit (former European Utility Week and

POWERGEN Europe). Milano, Italy,

www.powergeneurope.com

02.11. – 06.11.2020

International Nuclear Reactor Materials

Reliability Conference and Exhibition.

New Orleans, Louisiana, EPRI, www.custom.cvent.com

09.11. – 13.11.2020

International Conference on Radiation Safety:

Improving Radiation Protection in Practice.

Vienna, Austria, IAEA, www.iaea.org

postponed to 18.11. – 19.11.2020

INSC — International Nuclear Supply Chain

Symposium. Munich, Germany, TÜV SÜD,

www.tuev-sued.de

24.11. – 26.11.2020

ICOND 2020 – 9 th International Conference on

Nuclear Decommissioning. Aachen, Germany,

AiNT, www.icond.de

07.12. – 10.12.2020

SAMMI 2020 – Specialist Workshop on Advanced

Measurement Method and Instrumentation

for enhancing Severe Accident Management in

an NPP addressing Emergency, Stabilization and

Long-term Recovery Phases. Fukushima, Japan,

NEA, www.sammi-2020.org

17.12. – 18.12.2020

ICNESPP 2020 – 14. International Conference on

Nuclear Engineering Systems and Power Plants.

Kuala Lumpur, Malaysia, WASET, www.waset.org

Calendar

atw Vol. 65 (2020) | Issue 4 ı April

Nuclear Rockets

for Interplanetary Space Missions

Dr. William Emrich

Introduction Future crewed space missions beyond low earth orbit will almost certainly require propulsion

systems with performance levels exceeding that of today’s best chemical engines. A likely candidate for that propulsion

system is the solid core Nuclear Thermal Rocket or NTR. Solid core NTR engines are expected to have performance levels

that significantly exceed that achievable by any currently conceivable chemical engine.

Rocket engines operate by expelling a high temperature

gas through a nozzle to produce thrust. This thrust acts to

accelerate a spacecraft in the direction opposite that of the

expelled gas through the application of Newton’s Third

Law of Motion. In chemical rocket engines, the hot gas is

created in a combustion chamber where the propellants

are ignited and burned. Nuclear thermal rocket engines,

on the other hand, use nuclear reactors to supply the

heat needed to raise the propellant to high temperatures.

The high temperature gas exiting the rocket engines is

introduced into nozzle assemblies where the thermal

energy of the hot propellant gas is converted to kinetic

energy in the form of a directed high speed exhaust flow.

Historical Background

There have been several programs in the past that have

sought to develop solid core nuclear rocket engines. In the

late 1950’s, a NTR program was instituted called Nuclear

Engine for Rocket Vehicle Applications or NERVA [1]

which resulted in the construction of a number of prototypical

nuclear engines. The reactor development portion

of the NERVA program in the United States (called ROVER)

began at the Los Alamos National Laboratory in 1953 with

the intent being to design light, high temperature reactors

that could form the basis of a nuclear powered rocket. This

program was conceived as an alternative to the chemical

rocket engines currently under development that were

being designed to lift payloads into orbit. In 1961 the

NERVA program began designing and building working

nuclear rocket engines based upon the research previously

done under the ROVER program.

The NERVA program achieved the following milestones

over the life of the project:

p Nuclear rocket testing occurred between 1959 and

1973

p A total of 23 reactor tests were performed

p Highest power achieved was 4500 megawatts

p Highest temperature achieved was 2750 K

p Maximum thrust achieved was 1,100,000 Newtons

p Maximum specific impulse achieved was 850 seconds

p Maximum burn time in one test was 90 minutes

Figure 1 illustrates the configuration of a NERVA rocket

engine and shows one of the engines being test fired at

Nuclear Rocket Development Station in Jackass Flats,

Nevada in the United States.

The US Air Force also briefly worked on an innovative

NTR engine concept called a Particle Bed Reactor or PBR

[2] in which the hydrogen in the nuclear fuel element

flowed radially through a packed bed of fuel particles. This

engine had a very high thrust to weight ratio and was to be

used in a ballistic missile interceptor in a top-secret

program called Timberwind. This program, however, was

cancelled in the early 1990s after the fall of the former Soviet

Union before any substantial testing could be

accomplished.

The former Soviet Union itself also sought to develop a

nuclear rocket engine [3] as a response to the work being

done in the United States on the NERVA program. This

nuclear rocket program, which lasted from 1965 through

the 1980s, eventually developed the RD-410 nuclear rocket

engine that was fairly small as compared to the NERVA

engines. The fuel elements in this engine, however, were

191

FEATURE | RESEARCH AND INNOVATION

| Fig. 1.

NERVA Description and Testing.

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FEATURE | RESEARCH AND INNOVATION 192

made of a uranium/tungsten carbide material that allowed

them to operate at temperatures somewhat higher than

those achievable in NERVA. As a result, the RD-410 was

slightly more efficient than the NERVA engines.

Nuclear Rocket Engine Operational

Characteristics

In chemical rocket engines, a fuel (normally in conjunction

with an oxidizer) combusts to form the gaseous propellant

which is expelled through a nozzle to generate the thrust.

When speaking about chemical engines, therefore, the

terms fuel and propellant are often used interchangeably

since the fuel (that is, the substance that supplies the

energy to heat the propellant) and the propellant are one

and the same. In nuclear engines, however, the propellant

is simply the working fluid heated by the nuclear reactor to

produce the thrust. The fuel in this case is actually the

fissioning uranium in the nuclear reactor. When speaking

about nuclear engines, therefore, the term fuel is used to

describe the fissioning uranium in the nuclear reactor

and the term propellant is used to designate the working

fluid being expelled through the nozzle. It is interesting to

note that because of the extremely high energy density

characteristic of nuclear fuels, an entire crewed Mars

mission may be accomplished through the fissioning of less

than 200 g of 235 U.

The efficiency of rocket engines depends upon, among

other things, the temperature of the engine propellant

exhaust gases (e.g. the higher the temperature, the higher

the rocket efficiency). In chemical engines, the temperature

of the exhaust gases is limited by the amount of energy

that may be extracted from the fuel and oxidizer as they

react. Thus, chemical engines are said to be energy limited in

their efficiency.

An NTR engine, on the other hand, operates by

using nuclear fission to heat the propellant to high

temperatures. Because the energy released from the

fissioning of nuclear fuel is extremely high as compared to

that available from chemical combustion processes, the

propellant in an NTR can potentially be heated to

temperatures far in excess of that possible in chemical

engines. The main limitation of these engines results from

restrictions on the rate at which this heat energy can be

extracted from the nuclear fuel and transferred to the

propellant. This rate of energy transfer is limited by the

maximum temperature the nuclear fuel can withstand. It is

this temperature limitation that puts an upper limit on the

maximum efficiency attainable by solid core nuclear

thermal rocket engines. As such, NTR engines are said to be

power density limited in their efficiency.

To determine the efficiency of a rocket engine, be it

chemical or nuclear, a characteristic value called Specific

Impulse (or I sp ) is used which is analogous to liters per

100 km for an automobile. Specific impulse is calculated by

dividing the rocket thrust in Newtons by the propellant

mass flow rate in kg/sec. It has units of seconds and

physically represents the length of time a rocket engine

can produce one newton of thrust from one kilogram of

propellant. It is also proportional to the propellant exhaust

velocity (υ e ).

(1)

Also note that:

(2)

Equation 2 simply illustrates that at a given power level

specific impulse is inversely proportional to thrust. Specific

impulse can be related to the temperature of the exhaust

gas by performing a heat balance and using the First Law

of Thermodynamics.

(3)

where: Q = Reactor power

h = Enthalpy of propellant

c p = Specific heat of propellant

T = Temperature of propellant

In the above equations, the subscript “c” stands for the

conditions at the exit of the reactor and the subscript “e”

stands for the conditions at the nozzle exit. Rearranging

terms from Equation 3 then yields for the specific impulse.

(4)

Noting the following specific heat relationships for ideal

gases:

(5)

where:

γ = Specific heat ratio of propellant

R u = Universal gas constant

Also recalling that for isentropic flow temperature and

pressure can be related by:

(6)

where:

P = Pressure of propellant

By substituting Equations 5 and 6 into Equation 4 for the

specific impulse, it is found that:

(7)

Assuming that the nuclear engine is operating in space

with an infinitely large nozzle, the pressure ratio goes to

zero and we are left with an expression which represents

the specific impulse only in terms of the chamber temperature

and the propellant thermodynamic properties:

(8)

where:

F = Thrusting force

ṁ = Propellant mass flow rate

g c = Gravitational acceleration constant

Plotting Equation 8 for a chemical engine using liquid

oxygen and liquid hydrogen as propellants and for a

nuclear thermal rocket using only hydrogen as the

propellant, it can be seen in Figure 2 that the nuclear

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Nuclear Rockets for Interplanetary Space Missions ı Dr. William Emrich

atw Vol. 65 (2020) | Issue 4 ı April

| Fig. 2.

Specific Impulse Comparison between Nuclear and Chemical Rocket Engines.

engine provides about twice the specific impulse at a given

temperature as compared to a chemical engine. This

variance is due almost entirely to the difference in

molecular weight between the two exhaust gases.

So how does this efficiency increase using nuclear

thermal rocket engines translate into improved interplanetary

mission profiles? First, noting that most interplanetary

missions using high thrust propulsion systems

such as what would available using nuclear thermal propulsion

do not apply thrust for the entire flight, but rather

execute a series of thrusting maneuvers near the departure

and destinations planets with relatively long coast periods

between the planets. Normally, at least four major propulsive

maneuvers are required for round trip missions.

These main propulsion system burns include: 1) a departure

acceleration burn from home planet, 2) an arrival

deceleration burn at the destination planet, 3) a departure

acceleration burn from the destination planet and, 4) an

arrival deceleration burn back at the home planet. Second,

because the planetary alignments are continually changing,

these propulsive maneuvers cannot be performed

anytime one wishes, but only during certain windows of

time when the planetary alignments are favorable.

The various thrusting maneuvers described above may

be added together to yield what is called the total mission

velocity that describes the total velocity increment that

must be delivered to the spacecraft in order to complete

the mission. This velocity increment is a function of the

engine specific impulse and the vehicle mass fraction that

is defined to be the ratio of the spacecraft unfueled mass to

its fueled mass.

Applying the principle of conservation of momentum,

this high velocity propellant exhaust flow has the effect of

forcing the spacecraft forward as is illustrated in Figure 3.

Thrust is defined to be the force produced by the rocket

engine due to the time rate of change of momentum of the

exhaust gas

| Fig. 3.

Rocket Thrusting and the Conservation of Momentum.

Expanding the above equation and rearranging terms then

yields:

(10)

Note that in the above equation U + V = υ e = g c I sp , therefore,

taking the limit of the above equation as time goes

toward zero and applying Newton’s Second Law of Motion

along with the definition for specific impulse

(11)

By integrating the above equation, the total change in

spacecraft velocity possible for a given vehicle mass

fraction and specific impulse may be determined.

(12)

where:

V f = Final velocity of the rocket

(e.g. or total mission velocity)

m 0 = Initial mass of rocket (fully fueled)

m f = Final mass of rocket (fuel expended)

f m = Vehicle mass fraction (ratio of to )

The above equation is commonly known as the rocket

equation and its solution yields the maximum velocity

increment attainable by a space vehicle in terms of the

vehicle mass fraction and the engine specific impulse. For

example, if a spacecraft has a fairly doable mass fraction of

0.15 along with a nuclear engine having a specific impulse

of 900 sec., the total change in velocity that the vehicle is

capable of achieving is about 16.8 km/sec.

FEATURE | RESEARCH AND INNOVATION 193

(9)

where:

F ext = External forces acting on the rocket

(normally assumed to be zero in space)

p = momentum

t = time

m = mass

U = velocity of exhaust propellant

V = velocity of rocket

| Fig. 4.

Mars Mission Characteristics.

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FEATURE | RESEARCH AND INNOVATION 194

So … how does the rocket equation translate into

interplanetary mission characteristics? It turns out that

complete closed form solutions to the orbital mechanic

equations for these missions are generally not possible;

however, by using what are called patched conic approximations,

the mission characteristics of the interplanetary

voyage may be determined to a high degree of accuracy

using only fairly simple geometric constructs. Using

these patched conic equations in conjunction with

the 16.8 km/sec total vehicle velocity change calculated

above, the one way travel time between Earth and Mars

can be accomplished in about 160 days as illustrated in

Figure 4.

The minimum velocity increment required to execute

a Mars mission is through the use of a mission profile using

what is called a Hohmann transfer trajectory. This

minimum energy transfer trajectory requires a total

mission velocity of 11.4 km/sec and necessitates a one way

trip time of 259 days. If a chemical rocket engine having a

specific impulse of 450 sec. were used to execute this

mission, then a vehicle mass fraction of 0.075 would be

required. This small a vehicle mass fraction is completely

unrealistic and illustrates why nuclear rocket engines are

almost mandatory for any kind of practical interplanetary

travel.

Nuclear Rocket Engine System Characteristics

The fuel elements that comprise the reactor core in a

nuclear rocket engine are generally fabricated in the shape

of hexagonal prisms containing a number of axial holes

through which flows the hydrogen propellant. For a rocket

engine that produces approximately 100,000 N of thrust,

a reactor core would be expected to contain perhaps a

couple of hundred fuel of these fuel elements. In NERVA

rocket engines, the fuel elements were held in place in the

core by means of support elements containing moderator

material. These support elements held the six adjacent

fuel elements together in a grouping called a cluster. The

reactor core itself is surrounded by a reflector region

composed of beryllium to reflect back into the core

neutrons emanating from the fuel that would normally

escape the reactor. Control drums embedded in the

reflector serve as a control mechanism by which the core

reactivity can be adjusted. The drums are composed

of beryllium cylinders with a sheet of material which

strongly absorbs neutrons attached to one side. When the

absorbing material (usually boron carbide) is close to the

core, many neutrons which would be reflected back into

the core are instead absorbed in the neutron absorbing

sheet causing the core reactivity to decrease. When the

absorbing material is turned away from the core, the

| Fig. 5.

NERVA Core and Fuel Segment Cluster Detail.

| Fig. 6.

Possible Radial Flow Nuclear Rocket Fuel Element Configurations.

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beryllium portion of the control drum reflects the escaping

neutrons back into the core where their availability

increases the core reactivity.

Figure 5 below illustrates a NERVA fuel cluster and the

manner in which it is integrated into the reactor with

the reflector region and control drums.

While current thinking is primarily directed toward

core designs composed of these hexagonally shaped axial

flow fuel elements, other designs are also being considered.

These designs include the radial flow Grooved

Ring Fuel Element (GRFE) and the Particle Bed Fuel

Element (PBFE). These designs are illustrated in Figure 6.

Radial flow designs such as these have the advantage over

axial flow designs in that they can be made to have higher

surface to volume ratios leading to more compact reactor

configurations and are often amenable to using a wider variety

of fuel materials. One particular advantage of the

grooved ring fuel element configuration is that it can be

designed in such a way that the temperature distribution

across the entire fuel ring can be made to be nearly

isothermal [4].

Nuclear rockets operate using one of several types of

thermodynamic cycles that vary in complexity and

efficiency. For nuclear thermal rockets, these thermodynamic

cycles are “open” in that during operation, the

working fluid is discharged through the nozzle to produce

thrust after circulating only once through the engine

system. These engines typically use a turbopump to

highly pressurize the propellant prior to being introduced

into the reactor where the propellant is heated to high

temperatures before being discharged through the nozzle.

The pump is normally driven by an integrated turbine

system which is powered by propellant that has been

warmed somewhat using waste heat from the reactor.

One of the more common rocket engine cycles is illustrated

in Figure 7.

This particular engine cycle is called the “Hot Bleed

Cycle” and is commonly considered because of its

relative simplicity and high efficiency. The hot bleed cycle

characteristics are as follows:

1-2 Liquid propellant from the tank is raised to the

operating pressure after passing through the pump

portion of the turbopump.

2-3 After passing through the turbopump the propellant

circulates through the nozzle, support elements,

chamber walls, etc., gasifying the propellant.

| Fig. 7.

Hot Bleed Nuclear Rocket Engine Configuration.

3-4 The gaseous propellant flow splits, with the majority

of the flow being directed into the reactor core where

it is heated to several thousand degrees before exiting

the core into the engine exhaust plenum.

3-5 The rest of the gaseous propellant flow mixes with hot

propellant bled from the reactor exhaust plenum and

enters into the turbine portion of the turbopump.

5-6 The mixed propellant flow, which is now at a temperature

consistent with the maximum acceptable

turbine blade material limits, passes through the

turbine portion of the turbopump where it gives up

some of its energy to drive the pump portion of the

turbopump. After passing through the turbopump,

the propellant flow is discharged through a small

nozzle.

4-7 The remainder of the hot gaseous propellant in the

engine exhaust plenum is directed through the main

nozzle where the heat energy is changed to directed

kinetic energy producing thrust.

Advanced Nuclear Propulsion Concepts

Due to the material limitations of nuclear thermal rockets

having solid cores, the maximum practical specific impulse

achievable by these engines is in the range of 900 seconds.

To achieve significantly higher specific impulses, much

higher propellant temperatures will be required, thus

necessitating radically different nuclear core designs. One

method that has been considered in the past to achieve

these higher specific impulses is to use a nuclear pulse

system. In the pulsed nuclear rocket concept, small nuclear

bombs are ejected from the rear of a spacecraft and

detonated after they have traveled a suitable distance

FEATURE | RESEARCH AND INNOVATION 195

| Fig. 8.

Hot Bleed Nuclear Rocket Engine Thermodynamic Cycle.

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FEATURE | RESEARCH AND INNOVATION 196

| Fig. 9.

Orion Nuclear Pulse Rocket.

| Fig. 10.

Orion Flight Testing Using Putt Putts.

away from the vehicle. The vehicle itself is designed such

that a portion of the blast wave resulting from the nuclear

detonation is intercepted by a specially designed “pusher

plate” attached to the body of the spacecraft by giant shock

absorbers. These shock absorbers act to moderate the

spacecraft jerk (e.g. time rate of change of acceleration)

resulting from the impinging blast wave such that the

acceleration of the main body of the vehicle is reduced and

smoothed to levels which can be tolerated by the crew. An

illustration of a conceptual Orion nuclear pulse vehicle is

presented in Figure 9.

Such a pulsed nuclear propulsion program was actually

initiated in the United States during the late 1950s and

early 1960s under the project name Orion [5]. Several

small scale proof of principle models called Putt-Putts or

Hot Rods were actually built and flown. These proof of

concept vehicles used chemical rather than nuclear

explosives as the propulsive medium and after several

failures, one of the vehicles finally achieved stable flight

and flew to an altitude of about 30 meters as illustrated in

Figure 10.

Figure 11 illustrates what might be a typical pulsed

nuclear rocket dynamic response resulting from a series of

| Fig. 13.

Closed Cycle Nuclear Rocket Engine “Nuclear Light Bulb”.

| Fig. 11.

Dynamic Response of a Nuclear Pulse Vehicle.

| Fig. 12.

Open Cycle Gas Core Nuclear Rocket Engine.

nuclear acceleration pulses. Note that contrary to what

might be expected, the accelerations experienced by the

crew during the time period over which the detonations

are occurring can be made survivable, although probably

quite uncomfortable. No doubt, the crew would happily

accept being put into a state of suspended animation

during the thrusting phase of the mission rather than

experiencing such a stomach-churning ride!

Another method of achieving higher specific impulses

in to employ a gaseous fissioning core to eliminate the

problem of fuel melting at extremely high temperatures.

As might be expected, a number of significant design

challenges exist with this concept primarily with regard to

designing a feasible means of transferring heat from the

gaseous fissioning core to the gaseous propellant. There

are basically two different reactor configurations which

may be employed to construct a gaseous core nuclear

rocket engine. One concept may be described as the

“open cycle” configuration. An illustration of the open

cycles gas core nuclear rocket concept is presented below

in Figure 12. In this configuration, a fissile material is

injected into the core where it is subsequently vaporized

due to the high temperatures present there. The hydrogen

propellant is also injected into the core, but in such a

way that a stabilizing rotation is induced in the gaseous

fissioning core.

Chief among the feasibility questions with this core

configuration is the issue of keeping the gaseous fissioning

core from escaping through the nozzle at an unacceptably

high rate. To be practical, the gas core rocket must maintain

its gaseous core in a stable critical state, while minimizing

the loss rate of fissionable material through the

nozzle while simultaneously maximizing the heat transfer

rate to the hydrogen propellant and allowing it only to

escape through the nozzle. Such stringent requirements

Feature

Nuclear Rockets for Interplanetary Space Missions ı Dr. William Emrich

atw Vol. 65 (2020) | Issue 4 ı April

| Fig. 14.

“Nuclear Light Bulb” Simplified Flow Diagram.

will be no doubt be difficult to achieve in practice. It is

thought that specific impulses in the order of 2000 seconds

may be possible if near 100 % uranium plasma containment

is achieved.

Another gaseous core concept may be described as the

“closed cycle” or “nuclear light bulb” configuration. In the

nuclear light bulb, the gaseous uranium is confined in

closed transparent containers which allow radiant energy

from the core to be transmitted through the container

walls where the energy is absorbed in a seeded hydrogen

propellant which flows on the outside of the container.

This concept has the obvious advantage of containing

100 % of the nuclear fuel; however, it also introduces an

entirely new set of design challenges. Chief among these

design challenges is the problem of maintaining the

structural integrity of the transparent core containment

vessel in the presence of an extremely harsh temperature

environment while simultaneously allowing the transmission

of vast amounts of radiant energy through its

walls. These design challenges were addressed in a

program at United Technologies [6] in the 1960s when the

company had an active program underway to develop

a nuclear light bulb rocket engine. A diagram of the

engine concept developed by the company is illustrated

in Figure 13.

The radiation (primarily ultraviolet light) emitted from

the high temperature fissioning uranium plasma, passes

through the containment vessel’s transparent walls and is

absorbed in seeded hydrogen propellant which flows along

the outside of the containment vessel. This hot hydrogen

propellant is subsequently exhausted through nozzles to

produce thrust. The transparent walls of the containment

vessel are of particular concern in the nuclear light bulb

design. The material comprising the containment vessel

walls, therefore, must not only be highly transparent, but

must also be actively cooled to prevent overheating and

eventual vessel failure. In this design, the extremely hot

fissioning uranium plasma is prevented from touching the

transparent containment vessel by a vortex flow of seeded

neon gas which acts as a buffer between the containment

walls and the uranium plasma. The neon gas (along with

some entrained uranium) is continually extracted from the

edge of the reactor core where it is separated from the

uranium and cooled in a heat exchanger before being

reinjected back into the containment vessel. The rejected

heat from the neon is used to partially preheat the main

hydrogen propellant stream. The separated uranium is

also reinjected back into the containment vessel thus

preventing any uranium loss from occurring in the system.

A schematic diagram of the nuclear light bulb concept

is illustrated in Figure 14. In the United Technologies

experiments with the concept yielded equivalent specific

impulses of over 1300 sec.

Conclusions

The application of nuclear energy to space propulsion

systems has long been seen as a means to enable missions

to outer space that are not achievable by any currently

conceivable chemical based rocket propulsion system.

While nuclear rocket engines are clearly superior to

chemical rocket engine in that they deliver efficiencies that

are over twice that of the best chemical rocket engines, no

operational nuclear rocket engine has yet been developed.

It is anticipated that these engines, while deceptively

simple in concept, will no doubt require a daunting amount

of detailed engineering to finally develop a practical

engine system. These engineering details include not only

the usual thermal, fluid, and mechanical aspects always

present in chemical rocket engine development, but

also nuclear interactions coupled with some unique

materials restrictions. None of these engineering details

are expected to be insurmountable, however. Hopefully,

with the mounting desire within the United States and

elsewhere to send human to Mars, it may be that renewed

efforts will be made in the near future to once again initiate

programs to finally develop an operational nuclear rocket

engine.

References

[1] Finseth, J. L., “Overview of Rover Engine Tests - Final Report”, NASA George C. Marshall Space

Flight Center, Contract NAS 8-37814, File No. 313-002-91-059, (Feb. 1991).

[2] Haslett, R. A., “Space Nuclear Thermal Propulsion Final Report”, Phillips Laboratory,

PL-TR-95-1064, (May 1995).

[3] Harvey, B., “Russian Planetary Exploration History, Development, Legacy, and Prospects”,

Springer-Praxis Books in Space Exploration, ISBN 10: 0-387-46343-7, (2007).

[4] Emrich, W., “Principles of Nuclear Rocket Propulsion”, Elsevier Inc., ISBN 978-0-12-804474-2,

(2016).

[5] “General Atomic Division of General Dynamics, \”Nuclear Pulse Space Vehicle Study\”,

GA-5009, Vol. I thru IV, NASA/MSFC Contract NAS 8-11053, (1964).”

[6] Mcl.afferty, G. H., “Investigation of Gaseous Nuclear Rocket Technology – Summary Technical

Report”, United Aircraft Research Laboratories, Report H-910093-46, prepared under Contract

NASw-847, (November 1969).

Author

Dr. William Emrich

Senior Engineer

NASA – Marshall Space Flight Center

Huntsville, Alabama USA

FEATURE | RESEARCH AND INNOVATION 197

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SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 198

Serial | Major Trends in Energy Policy and Nuclear Power

Research in Support of European Radioisotope

Power System Development

at the European Commission’s Joint

Research Centre in Karlsruhe

Daniel Freis, Jean-François Vigier, Karin Popa and Rudy J.M. Konings

1 Introduction The urge to discover the unknown, to explore the unexplored and to broaden our knowledge

beyond the limits of the present is inherent to human nature. One of the most interesting and fascinating fields of

science is the exploration of the cosmos, either from Earth using telescopes or by sending automated probes to other

planets and into the vastness of space.

| Fig. 1.

Apollo astronaut photo of a SNAP-27 RTG on the Moon. Photo: NASA.

A basic requirement to operate automated

spacecraft successfully over the

course of an exploratory mission, is

the reliable supply of long-lasting

power. If independence of solar radiation

is required, e.g. when travelling

into deep space or to the dark side of

planetary bodies, nuclear energy

becomes advantageous compared to

other potential sources of energy. The

utilisation of nuclear power for applications

in space had been considered

since the early beginnings of space

flight in the late 1940s, and the first

Radioisotope Power System (RPS) in

space was already launched by the

U.S. Navy in 1961, onboard the Transit

4A navigational satellite [1,2]. Since

then RPS have enabled some of the

most spectacular missions in the

history of space exploration [1-7],

mostly performed by the USA but also

by the former Soviet Union, China and

Europe (via cooperation with the

USA). RPS were used on satellites for

navigation, meteorology and communication

[8], they have powered

scientific instruments on the Moon

(Figure 1), and they were used for

many of the most famous and exiting

exploratory endeavours, such as

the Pioneer missions to Saturn and

Jupiter [9,10], the Viking missions to

Mars [11], and the Voyager 1 & 2

spacecraft, which travelled beyond

the boundaries of our solar system

and are still delivering scientific

results from the interstellar medium,

more than 40 years after their launch

[12,13]. More recently, the radioisotope-

powered missions Galileo,

Ulysses and Cassini-Huygens were

exploring Jupiter, the Sun and

Saturn/Titan, respectively. These

more recent missions were performed

in collaboration between the National

Aeronautics and Space Administration

(NASA) and the European Space

Agency (ESA) [14]. Historically, this

was the only way for Europe to gain

access to space nuclear power systems.

In 2005 a European Working Group

on Nuclear Power Sources for Space

identified RPS as a “key enabling

technology for future European activities

in space” [15], and suggested the

establishment of an European safety

framework for space nuclear power

sources and the development of

the technical capabilities to perform

nuclear powered missions indendently

[16,17]. As a consequence, a research

and development programme was

launched by ESA for the production of

European RPS to satisfy thermal

management and electrical power

needs for spacecraft [16,17,18,19].

In the past, most RPS for space

missions were based on the plutonium

isotope Pu-238 [1-5], a radionuclide

which is superior to other isotopes,

because of its high specific power of

0.567 W/g, low radiation, compatibility

with cladding materials and

chemical stability as oxide. Pu-238

has a half-life of 87.7 years which

enables long-lasting missions [20].

Unfortunately, there is a global

shortage of this isotope, the efforts

associated with its production are

high [21] and there are currently no

facilities for its synthesis in Europe.

An alternative is the americium

isotope Am-241, which is more easily

available, since it is produced through

decay from Pu-241 and can be

extracted isotopically pure from

existing stocks of civil plutonium in

France or the United Kingdom via

chemical extraction [22]. Therefore,

ESA has decided to study the use of

Am-241 for its RPS development

[5,16,17]. However, Am-241 has some

disadvantages compared to Pu-238,

such as a lower power density of

0.114 W/g and slightly higher radiation

levels. In addition, the oxide

shows chemical instability at high

temperatures, the experience with

Am241 is limited and additional

research and safety assessment is

needed before it can be used for space

applications.

Within the ESA research programme,

the UK’s National Nuclear

Laboratory (NNL) is exploring the

cost effective production of Am-241

and the University of Leicester (UoL)

is developing a European Radioisotope

Heater Unit (RHU) and Radioisotope

Thermoelectric Generator

(RTG) [16,23,24]. To support these

efforts, the European Commission’s

Joint Research Centre (JRC) in Karlsruhe

is investigating methods to

stabilize americium in the oxide

form and to establish a safe and

reliable pelletizing process [20,25].

In collaboration with UoL, safety

relevant properties and behaviour of

Americium oxide are assessed under

representative conditions for storage

on Earth, operations in space as

well as hypothetical accident and

post-accident environments [16,26],

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Research in Support of European Radio isotope Power System Development at the European Commission’s Joint Research Centre in Karlsruhe ı Daniel Freis, Jean-François Vigier, Karin Popa and Rudy J.M. Konings

atw Vol. 65 (2020) | Issue 4 ı April

and the compatibility with the cladding

material is tested. Complementary

work is performed to develop a

qualified welding methodology of the

safety encapsulation.

2 Energy Supply in Space

In order to operate spacecraft, a

reliable source of power in the form of

electricity and heat is required.

Electricity is needed to power onboard

electronic systems such as navigation

and manoeuvring systems, onboard

computers, lighting, robotics, scientific

instruments and communication

systems. In some cases, spacecraft are

equipped with electric propulsion

systems, and electricity for life support

is needed if the mission is manned.

Heat is needed in cold environments

to keep sensitive spacecraft components

at minimum operational or

survival temperature, e.g. during

lunar nights.

Primary energy sources can be

chemical, solar or nuclear. Some of

these are limited with respect to their

power or energy density, and the

profile of each individual mission

determines which energy sources can

be utilized. Table 1 shows typical

energy densities for different energy

sources.

Chemical energy sources in the

form of solid or liquid fuels can release

a large quantity of energy in a very

short time, but they are limited with

respect to total energy density. For instance,

chemical fuels for propulsion

can be used whenever high thrust is

needed for a short time, e.g. as rocket

fuel to overcome the gravity field of

earth, but they have shortcomings if

long-lasting power or long acceleration

times are needed, e.g. to reach

the high velocities necessary for interplanetary

or even interstellar travel.

Chemical energy in the form of

batteries or fuel for fuel cells can be

used when onboard power is needed

for no more than a few weeks, or as

rechargeable energy buffer to supply

peak loads or to bridge periods without

sunlight. For missions, which

require continuous power supply for

an extended time, only solar or

nuclear energy sources are feasible,

since the payload associated with

chemical fuels or batteries would

simply become too high.

Solar energy is principally unlimited,

as long as the solar cells, used

to convert the radiation energy into

electricity, are not degrading, and as

long as they can be adjusted in the

direction of the sunlight and the

spacecraft is not in the shadow of

planetary bodies or too far away from

the sun. However, their effective area,

the conversion efficiency and the

intensity of the solar radiation determine

the power density of solar cells.

This intensity decreases inversely with

the square of the distance from the

sun, as shown in Figure 2, and if the

distance becomes too large solar

energy becomes unpractical. For

example, while the solar constant is

1.367 kW/m 2 at the semi-major axis of

Earth, at one Astronomical Unit (AU)

distance to the sun, it decreases

to only 51 W/m 2 or 3.7 % at the semimajor

axis of Jupiter (5.2 AU). Therefore,

solar arrays are not an option for

all research missions to the outer solar

system, but also not if a system is to be

operated during long periods of darkness,

for example during the lunar

nights, which last 14 days.

Nuclear energy has the highest

power densities of all possible onboard

energy sources, and can deliver

reliable power over very long time

periods. Most importantly, it is independent

of sunlight. There are two

types of space nuclear power systems;

Reactor power systems (small nuclear

reactors), which generate power by

Energy source

2 H 2 + O 2 13.33

N 2 H 4 * + O 2 9.75

2 Li + O 2 12.2

Li-ion battery 0.9

Fission of U-235** 8.2 · 10 6

Decay of Pu-238*** 3.3 · 10 5

Decay of Am-241*** 7.1 · 10 4

controlled fission of fissile isotopes,

such as U235 or Pu-239, and Radioisotope

Power Sources or Systems

(RPS), which obtain their energy from

the spontaneous decay of radioactive

isotopes. Both types can generate

heat for temperature control and/or

electricity via additional energy

conversion systems.

While nuclear reactors are

generally suited for applications,

which need significant power levels

above 10 kW, RPS are employed

whenever a limited amount of solarindependent

power, up to 5 kW, is

needed for a longer time period. RPS

are compact, long-lived, reliable,

robust, radiation resistant, solarindependent,

maintenance-free, and

they have energy densities, which are

several orders of magnitude above

chemical power sources (Table 1)

[1,2,3]. Figure 3 shows qualitatively

the different regimes of power levels

and durations, where different energy

sources are applicable.

Space power systems, which are

based on the decay heat of radioisotopes,

can be distinguished into

systems which make direct use of

the thermal energy, and systems

which convert heat into electricity

(Figure 4). In both cases the employed

radioisotope is the power

Energy density, MJ/kg

| Tab. 1.

Energy densities of typical energy sources.

*Hydrazine, **total fission, ***over 20 years mission time

SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 199

| Fig. 2.

Intensity of solar radiation.

| Fig. 3.

Application of different energy sources (reproduced from references 1 and 3).

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SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 200

| Fig. 4.

Elements of radioisotope power systems.

source while the heat sink is provided

by space. Systems which make direct

use of the thermal energy are called

Radioisotope Heater Units (RHU).

They provide heat to the space craft

to keep sensitive electronics warm

without using heavy and complicated

heat distribution systems, and without

creating electromagnetic interference.

Heat-to-electricity conversion systems

can be classified into dynamic

and static systems. The dynamic

systems employ moving parts and use

a thermodynamic cycle to convert

heat into electricity, e.g. a Stirling

engine [27], and show principally the

highest conversion efficiencies. The

earliest efforts were focussed on the

development of dynamic conversion

systems, and the first RPS SNAP-1

(SNAP stands for Systems for Nuclear

Auxiliary Power) in 1959 was based

on a Ce-144 powered mercury

Rankine cycle [1]. But despite their

high conversion efficiency, dynamic

conversion systems have not yet

reached the reliability required for the

operation of a space probe, which

might be on a mission for several

decades without the possibility for

maintenance or repair, and no

dynamic conversion system was ever

used in space.

The static heat-to-electricity conversion

systems are called Radioisotope

Thermal Generators (RTG).

RTG have no moving parts and use the

thermo electric principle, also known

as the Seebeck effect, to generate

electricity. This phenomenon was

discovered in 1794 by the Italian

scientist Alessandro Volta and, independently,

in 1821 by the German

physicist Thomas Johann Seebeck.

If two dissimilar materials are connected

in a closed circuit and a

temperature difference is applied over

the two junctions, a voltage can be

measured and electricity is generated

(Figure 5). Such a device is called a

| Fig. 5.

Thermoelectric circuit.

thermo electric couple or thermocouple.

In addition, static heat conversion

is also possible by thermionic

conversion, where a flow of electrons

is induced from a hot to a cool surface

via thermionic emission.

Thermoelectric conversion is not

very efficient and practical RTG

systems using SiGe or PbTe/TAGS

thermocouples show typical power

conversion efficiencies of 6 % to 7 %

[5]. To improve efficiency, development

of high temperature thermoelectric

materials including skutterudites

and Zintl-based systems is

ongoing [28,29]. However, if operated

at low temperatures or under a protective

gas cover, existing RTG are very

reliable, show low degradation and

can provide power over many decades.

Because of the importance of reliable

and maintenance-free systems for

automated space probes, relatively

low conversion efficiencies are usually

accepted.

The most important design

criterion for any space nuclear power

system, including all forms of RPS, is

safety. If an RPS shall be employed on

a space application, it must comply

with resolution 47/68 of the United

Nations General Assembly on the

Principles Relevant to the Use of

Nuclear Power Sources in Outer

Space. The resolution defines that the

use of RPS shall be restricted to those

space missions, which cannot be

performed by non-nuclear energy

sources in a reasonable way. It also

states that the design and use of the

RPS shall ensure that the hazards

during operation and foreseeable

accidents are kept below acceptance

levels and that radioactive material

does not cause a significant contamination

of the biosphere and outer

space [30].

In order to comply with these

requirements, RPS are designed to the

meet highest safety standards. The

fuel is encapsulated in a cladding of a

| Fig. 6.

Radioisotope power source.

highly refractory noble metal like

iridium or platinum-rhodium alloys

(Figure 6), which can withstand the

most extreme conditions (e.g. launch

pad explosion, Earth re-entry accidents).

The cladding is surrounded by

thermal insulation, usually made of

pyrolytic graphite, which shall protect

the cladding from reaching peak

temperatures during aerodynamic

heating. Finally, the thermal insulation

is surrounded by an aeroshell

made of carbon-carbon composite

(fine-weaved pierced fabrice), which

provides additional protection from

postulated launch vehicle explosions

or against impacts on hard surfaces at

terminal velocity [1,5,14].

3 Radioisotopes for RPS

The selection of suitable radioisotopes

for application in space RPS is based

on a number of criteria; among them

are a long half-life, high isotopic power

and a low level of penetrating radiation.

In addition, a chemically stable

compound with high density should

exist, which can serve as stable host for

the decay products and is compatible

to the encapsulation materials and the

potential operating or post-accident

environments. Furthermore, the compound

should resist high temperatures

and should not disperse into inhalable

small particles, in case of an accident.

A low solubility in the environment

(water) and the human body are also

advantageous [4,5].

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Isotope Half-life (y) Isotopic power (W/g) Principal decay mechanism Comment Shielding (typically)

Am-241 432.8 0.114 alpha Soft gamma radiation 2 mm lead equivalent

Cs-137 30.04 0.417 beta Gamma emitter Heavy

Ce-144 285 2.08 beta Gamma emitter Heavy

Cm-242 0.45 122 alpha Strong neutron emitter Heavy

Cm-244 18 2.84 alpha Strong neutron emitter Heavy

Po-208 2.93 18.1 alpha Short half-life None

Po-210 0.38 144 alpha Short half-life None

Pu-238 87.7 0.567 alpha Very soft gamma radiation None

Sr-90 28.79 0.907 beta Bremsstrahlung Significant

| Tab. 2.

Radioisotopes for space applications [31,32].

Since the specific power correlates

inversely to the half-life, a compromise

has to be found between specific

weight and volume of the heat source

on one side, and a long-lasting stable

power output during the required mission

time on the other side. Therefore,

the selection of a suitable radioisotope

always depends on the concrete

application. Alpha emitters tend to be

better suited than beta emitters are,

because the alpha decay energy is

typically in the range between 5 MeV

and 6 MeV per decay event, for

example compared to 0.546 MeV for

the beta decay of Sr-90, and the alpha

particles do not generate Bremsstrahlung

when stopped in the surrounding

matter.

Other important criteria are the

availability of the selected isotope, as

well as the production costs and

necessary infrastructure and effort

to process the radioactive material.

Table 2 gives an overview over the

most common radioisotopes for space

RPS, of which Pu-238 is by far the

most significant. If not mentioned

otherwise, all nuclear data were taken

from the JEFF-3.1 nuclear data library

[31] via Nucleonica.com [32].

4 Properties of Plutonium-

238 & Americium-241

The development of European RPS is

based on the strategic decision of ESA

to utilize Am-241 and to take advantage

of the existing nuclear infrastructure

related to the civil reprocessing of

spent nuclear fuel in Europe, rather

than to establish an expensive production

capability for Pu-238 [16,17].

In order to understand the impact of

this choice on the RPS design characteristics

and the production process, a

comparison of both isotopes has to be

made. Table 3 summarizes the most

important properties of Am-241 compared

to Pu-238.

Pu-238 is an isotope of the chemical

element plutonium, an actinide

which is artificially created in nuclear

reactors. It was the first isotope of

plutonium, which was discovered by

Glenn T. Seaborg in 1940 [33], and it

is the most important and most widely

adopted radioisotope for space power

applications, due to its high power

density, long half-life, chemical stability

as oxide, and its low neutron and

soft gamma emissions. So far, Pu-238

is the only radioisotope used for RPS

in space by the USA and China, while

the former Soviet Union also utilized

Po-210.

Pu-238 has a half-life of 87.7 years

and an isotopic power of 0.567 W/g.

The isotope decays primarily via alpha

decay to U-234, with a decay energy

of 5.59 MeV. The main radiation emissions

of Pu-238 are alpha particles

with an average energy of 5.49 MeV.

In addition, the isotope emits soft

gamma radiation (main energies:

43.5 keV & 99.85 keV) with low emission

probability, and Auger electrons,

which in turn generate X-rays at

17.11 keV and 13.61 keV (main lines),

also with relatively low emission

probabilities. For a sintered and encapsulated

pellet, the self-shielding

effect and encapsulation are more

than sufficient to shield these radiations.

Spontaneous fission occurs with

a negligible probability of 1.86E-09,

and the spontaneous fission reaction

creates a neutron yield of circa

2300 n/(s g) (oxide). However, alphaneutron

(α-n) reactions in natural

oxygen cause an additional neutron

yield of circa 13 400 n/(s g) in plutonium

oxide [34]. The (α-n) reactions

can only occur in the low abundancy

isotopes O-17 and O-18, while the

threshold energy of O-16 is too high

(15.2 MeV) [34]. The neutron yield in

pure Pu-238 oxide can be reduced to

circa 2700 n/s-g [5] if the oxygen is

depleted in O-17 and O-18 by 98 %

[21].

Metallic plutonium has a density

of 19.77 g/cm 3 (Pu-238, α-phase at

room temperature and atmospheric

pressure), which is the highest density

form and would allow a volumetric

power density of up to 11.21 W/cm 3 .

However, the metal shows six different

structural mo difications at ambient

pressure in the temperature range

from 0 K (-273.15 °C) to 640 °C (melting

point), and the phase transitions

cause significant dimensional changes

as well as alterations of the mechanical

and thermal properties (Figure 7).

In addition, plutonium metal is burnable,

and the powder is extremely

pyrophoric. The first RTGs in the

1960s were still fuelled with metallic

Pu-238, and designed to burn-up into

fine particles below 30 nm and disperse

into the atmosphere in case of

an re-entry accident 1 . This safety

philosophy had to prove itself, when

the Transit satellite 5BN-3 failed

to achieve orbit in 1964, and the

SNAP-9A RTG re-entered the atmosphere,

carrying about 1 kg Pu-238

metal. As predicted, the metallic

fuel completely burned-up and was

Pu-Metal PuO 2 Am-Metal AmO 2

Half-life: 87.7 y 432.8 y

Density: 19.85 g/cm 3 11.46 g/cm 3 13.67 g/cm 3 11.68 g/cm 3

Power density:

0.567 W/g

0.500 W/g

(0.418 W/g)*

0.114 W/g

0.101 W/g

(0.088 W/g)**

Thermal conductivity: 6 – 16 W/m K 35 3 – 10 W/m K 37 10 W/m K ~ 2.0 W/m K 38 ***

Melting point: 640 °C 2744 °C 36 1176 °C 35 2113 °C 42

| Tab. 3.

Properties of Pu-238 and Am-241 (Metal and Oxide). *Typical isotopic composition, **Stabilized with 12 % U, ***Sub-stoichiometric

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SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 202

| Fig. 7.

Thermal conductivity of metallic plutonium structural modifications [35].

| Fig. 8.

Production of Am-241 by neutron capture and

β-decay.

dispersed into the atmosphere where

it was diluted to low concentrations

and did not cause any unacceptable

health hazard [1,8,14].

After the Transit 5BN-3 accident

and with the upcoming of larger RPS

with higher radioactive inventory the

dispersion approach was no longer

accepted and a new fuel form, which

would stay intact at re-entry was

needed. Since then, the preferred

chemical form of Pu-238 for RPS is

plutonium dioxide (PuO 2 ), safely

encapsulated in a cladding of high

refractory material which can safely

contain the radioactivity under all

credible circumstances [8]. PuO 2 is a

ceramic material with a high melting

point of 2744 °C [36], which can be

sintered into stable pellets. The compound

crystallizes in the face centred

cubic (fcc) structure (space group

Fm3¯m) [37], has a high chemical

stability, a low solubility in water

and does not react with the typical

cladding materials, such as iridium or

platinum alloys (e.g. Pt20Rh or

Pt30Rh). In addition, it serves as a

good host for U-234, the decay product

of Pu-238, which is also crystallizing

in the fcc structure.

Am-241 is an isotope of the radioactive

element americium. It belongs

also to the actinides and has the

atomic number 95. Like plutonium,

americium is an artificial element and

was discovered by the group of Glenn

T. Seaborg in 1944. Americium is

usually created in nuclear reactors

by neutron capture and radioactive

decay (Figure 8). However, during

irradiation not only Am-241 but also

other americium isotopes are created,

which are unwanted in RPS. Isotopically

pure Am-241 is produced continuously

in the stocks of civil plutonium

through beta decay of Pu-241

(t 1/2 =14.33 y), from where it can be

separated using chemical methods.

A cost efficient separation and purification

process (AMPEX) was developed

and demonstrated by the UK’s

National Nuclear Laboratory (NNL)

to separate ingrown Am-241 from

plutonium [22,39].

Am-241 has a half-life of 432.8

years and an isotopic power of

0.114 W/g. The isotope decays

primarily via alpha decay to Np-237.

In a final repository Am-241 is one of

the most important drivers for the

medium- term heat load, and therefore

the required gallery space, and

Np-237 (t 1/2 =2.14∙10 6 y) is one of the

significant isotopes driving long-term

radiotoxicity [40,41]. The main radiation

of Am-241 are alpha particles

with an average energy of 5.47 MeV.

Unlike Pu-238, Am-241 emits significant

gamma radiation at 59.54 keV

(main line) with a probability of 36 %

and also Auger electrons, which cause

X-rays at 14.44 keV (probability

33 %). Even though the radiation is

still relatively soft, shielding and

remote handling tools are required if

larger amounts are to be processed,

and especially when the material is in

solution and self-shielding is not effective.

Once the pellets have been

sintered and encapsulated the radiation

decreases. However, it remains

still significant and adequate radiation

protection measures for workers

need to be in place. A dose rate of

circa 150 µSv/h in 10 cm distance is

estimated for a typical full scale RHU

containing 26 g AmO 2 encapsulated in

1.8 mm Pt30Rh.

Am-241 has a very low probability

for spontaneous fission of 4.3E-12,

and the spontaneous fission reaction

creates a negligible neutron yield of

circa 1.2 n/s-g (oxide). However, as in

the case of Pu-238, Am-241 oxide

emits additional neutrons from the

alpha-neutron (α-n) reaction in natural

oxygen. This reaction causes an

additional neutron yield of circa

2700 n/(s g) 34 . While this is significantly

lower compared to Pu-238 by a

factor of six, it has to be considered

that for the same thermal power about

five times more Am-241 is needed.

Therefore, also in the case of Am-241

oxide O-17 and O-18 depletion is

needed to reduce the neutron yield to

acceptable levels [5].

Metallic americium has similar

disadvantages as metallic plutonium

for the use in RPS. In addition, its

density is relatively low compared to

the oxide (13.67 g/cm 3 α-phase at

room temperature). Elemental americium

is a soft metal, which oxidises

quickly in the atmosphere forming

a protective oxide layer. At room

temperature americium forms a

stable hexagonal α-phase (space

group P6 3 /mmc) [35], at 769 °C it

changes into the cubic β-phase (space

group Fm3¯m), and at 1077 °C it

converts to the γ-phase showing a

body- centered cubic structure [35].

The phase transitions cause dimensional

changes, however not as significant

as in the case of plutonium. The

melting point of metallic americium is

at 1176 °C. Americium metal powder

is also very pyrophoric and metallic

americium would definitively burn-up

in case of an uncontained re-entry

accident.

The preferred form of Am-241 for

space applications is americium oxide,

a ceramic material with a density of

11.68 g/cm 3 which can be sintered

into pellets [6,16,20,25]. However,

there are two major compounds which

are relevant for applications in space,

the cubic dioxide (AmO 2 ) (α-phase,

space group Fm3¯m) and the

sesquioxide (Am 2 O 3 ), which exists in

the hexagonal form (Aphase, space

group P3¯m1) and the cubic form

(C-phase, space group Ia3¯). Unfortunately,

the americium-oxygen system

shows a complex behaviour. The

melting point of AmO 2 is at 2113 °C

[42], but at high temperatures and

in the vacuum of space americium

dioxide loses oxygen. Due to this

process, it transforms into substoichiometric

AmO 2-x , thereby slowly

increasing its volume, until it finally

converts into the hexagonal sesquioxide

[37,43,44]. This process causes

significant dimensional changes and

can lead to decompo sition of the pellets

[25,45]. In addition, the release of

oxygen can cause pressure build-up

and potentially corrode surrounding

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structures. On the other higher,

americium sesquioxide is prone to

oxidation at lower tem peratures and

will slowly convert into the di oxide in

air, again undergoing significant

structural modifications. After several

weeks of storage, even under low

oxygen partial pressures, this effect,

in combination with selfirradiation

from α-decay, will cause Am 2 O 3

pellets to disintegrate into black

dioxide powder. Both pheno mena, the

reduction of AmO 2 at elevated temperatures

and the oxidation of Am 2 O 3

at low temperatures, are problematic

with respect to the integrity of the fuel

pellets and can cause increased dispersion

of radio active material in case

of certain accident scenarios [25].

5 The Minor Actinide Laboratory

at the Joint Research

Centre Karlsruhe

The Joint Research Centre is the

European Commission’s science and

knowledge service. Its mission is to

support EU policies with independent

evidence throughout the whole policy

cycle. Its work has a direct impact on

the lives of citizens by contributing

with its research outcomes to a

healthy and safe environment, secure

energy supplies, sustainable mobility

and consumer health and safety. The

JRC hosts specialist laboratories and

unique research facilities and is home

to thousands of scientists working to

support EU policy (https://ec.europa.

eu/jrc/en).

The JRC in Karlsruhe belongs to

the Directorate for Nuclear Safety and

Security (Directorate G), where JRC’s

nuclear work programme, funded by

the EURATOM Research and Training

Programme, is carried out. The

Directorate contributes to the scientific

foundation for the protection of

the European citizen against risks

associated with the handling and

storage of highly radioactive material,

and scientific and technical support

for the conception, development,

implementation and monitoring of

community policies related to nuclear

energy. Research and policy support

activities of Directorate G contribute

towards achieving effective safety and

safeguards systems for the nuclear

fuel cycle, to enhance nuclear security

then contributing to achieving the

goal of low carbon energy production.

The JRC supports the ESA

research programme on developing a

Euro pean Radioisotope Heater Unit

(RHU) and Radioisotope Thermoelectric

Generator (RTG). These activities

are focussed on investigating

methods to stabilize americium in the

oxide form and to establish a safe and

reliable pelletizing process [20,25].

In colla boration with UoL, safety

relevant properties and behaviour

of americium oxide are assessed

[16,26].

Am-241 emits a significant amount

of gamma radiation, and working

with Am-241 can result in high dose

rates for the operating personnel.

Remote operated and shielded

equipment is advantageous or even

necessary in order to prepare

americium- based pellets for RPS. The

JRC in Karlsruhe has a unique infrastructure

for handling of highly

radiative actinide materials, the socalled

Minor Actinide Laboratory

(MA-Lab) [46]. It is of high relevance

for safety research on fuels for transmutation

in Europe, as it is one of the

only dedicated facilities for the

synthesis of minor actinide containing

materials, either for property

measurements or for the preparation

of irradiation experiments.

The MA-lab consists of seven

glove-boxes with protection walls

forming two separate chains. A

schematic lay-out of the Ma-Lab is

shown in Figure 9. The glove boxes

are shielded by 50 cm neutron

shielding and 5 cm of lead. Based on

the thickness of the water and lead

wall, the mass limits have been

calculated to 150 g of Am-241 or 5 g of

Cm-244. The glove boxes can be

accessed manually from the back if

radiation levels are low enough to

perform experiment pre paration or

maintenance. In addition, tele-manipulators

and remote operated automated

equipment can be used for

operation at high dose rates.

The glove boxes of the minor

actinide laboratory are configured as

complete preparation chain for minor

| Fig. 9.

Minor Actinide Laboratory at JRC-Karlsruhe [46].

actinide containing samples from the

base material to the fully encapsulated

sample, and the MA-Lab represents

an ideal infrastructure for preparation

of highly radiating americium

pellets and fully qualified fuel pins.

The synthesis of the base material

(powder) is performed in the glove

box named “infiltration”. The process

is dust-free, based on the so-called gel

supported precipitation [47] and the

porous bead infiltration technique

[48]. This process is highly flexible

and easily adapted to the requirements

and specifications of new

sample compositions. The next glove

box contains a calcination furnace and

other equipment for powder preparation.

The prepared powders are dust

free, the individual beads typically

show heterogeneous size distributions

between 30 µm to 120 µm and are

ideal for pressing pellets. The ready to

press powder can be transferred via

an automated channel to the next

glove box, where it can be pressed to

pellets. After sintering in reducing

or oxi dizing atmosphere (glove box

“ Sintering”) the pellets are fully

characterized and inserted into a

cladding. Finally, pin welding and

non- destructive weld examination are

performed in the two last, alpha free

glove boxes.

6 Stabilisation of

Americium Oxide &

RHU-Size Prototype Pellet

Production

Unlike plutonium oxide, which is

stable in a broad range of temperatures

and oxygen potentials,

americium oxide is prone to phase

changes and disintegration in changing

environments [25]. If americium

oxide is sintered under oxidizing

conditions into AmO 2 , it releases

oxygen at elevated temperatures in

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SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 204

| Fig. 10.

Small (left side) and large (right side) scale prototype pellet.

the vacuum of space and changes into

sesquioxide (Am 2 O 3 ), thereby undergoing

strong structural reorganization,

density changes and disintegration.

If americium oxide is

sintered under reductive conditions

into Am 2 O 3 , it will transform into the

dioxide under accident conditions,

but also under the influence of selfirradiation

even at low oxygen potentials,

which leads to its total disintegration.

JRC has investigated possibilities

to stabilize americium dioxide in its

cubic form under a broad range of

temperatures, in oxidizing as well as

| Fig. 12.

Small scale prototype Pt30Rh encapsulation.

| Fig. 11.

Crystallographic swelling of (Am 0.80 U 0.12 Np 0.06 Pu 0.02 )O 1.8 mixed oxide under alpha self-irradiation.

Values for PuO 2 and AmO 2 swelling are reported for comparison [25].

reducing atmospheres. A solution was

found by inserting 12 % of uranium

into the americium oxide (in addition

to 6 % Np and 2 % Pu already present).

Thereby, it was possible to stabilize

the cubic phase and to sinter a number

of discs and pellets, including a

prototype pellet in the dimensions of

the US LWRHU [49] under moisturized

Ar/H 2 atmosphere and a

larger disc representative for a future

European RHU [16] (Figure 10).

Due to the absence of phase

changes, the stabilized material

showed a good sintering behaviour

and it was possible to sinter a number

of discs and pellets with good quality

and without cracking. After sintering

oxidation testing was performed and

the material proved stable up to

1000 °C. This result represents a

significant improvement with respect

to safety of the material against radioactive

material dispersion in case of

accidental conditions. In addition, the

macroscopic and crystallographic

swelling was assessed on the small

scale protype pellet (Figure 10) over

time. While no macroscopic swelling

was observed, only low crystallographic

swelling occurred due to

self-irradiation, which saturated after

circa 60 days. Overall the pellet

showed good long-term structural

and dimensional stability under selfirradiation

conditions (Figure 11)

[25].

7 Development of Welding

Methodology

In order to be able to meet the launch

safety requirements and safely ship

RPS sealed sources to sites, where they

can be assembled into RHUs or RTGs

and subsequently be installed onto a

spacecraft, it is necessary to develop

containment technologies that meet

these requirements. The first layer of

containment immediately surrounding

the fuel pellets is the cladding, which

must ensure the enclosure of radioactivity

during storage, normal operation

and accident scenarios. The

encapsulation has to be performed in a

nuclear installation, ideally the manufacturing

site, and it has to be ensured

that the fueled clads are free of external

contamination.

In order to test the feasibility of

our welding equipment and to gain

experience in the welding of Pt30Rh

capsules, two types of Pt30Rh-encapsulation

were constructed and

welding tests were performed. The

first capsule design had similar

dimensions as the US LWRHU (Figure

12) and the second capsule design

was made according to input by UoL

to host (Am,U)O 2 pellets of 15 mm

diameter and 20 mm height.

The capsules were welded using

established Tungsten Inert Gas

welding equipment, which is also

used in the frame of qualified welding

of fuel rodlets for irradiation experiments

[41]. Non-destructive as well as

destructive weld examinations were

performed and showed that good

welding results were achieved;

indicating that future welding quality

criteria can be met (Figure 13).

8 Conclusions

Radioisotope power sources are a key

enabling technology for exploratory

missions into deep space or to the dark

side of planetary bodies, and the

European Space Agency is sponsoring

the development of Am-241 based

radioisotope power systems. The

development of a new RPS based on

americium is a challenging task. The

optimization of the fuel is a key issue,

as the oxide of americium has significantly

different properties compared

to that of Pu-238, both in terms of

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| Fig. 13.

Large scale prototype Pt30Rh encapsulation (left side) and dye penetrant test of weld (right side).

material engineering and handling.

JRC supports the development of a

European radioisotope heater unit

and radioisotope thermoelectric generator.

These activities are focussed

on investigating methods to stabilize

americium in the oxide form and

to establish a safe and reliable pelletizing

process. Safety relevant properties

and behaviour of americium

oxide, as well as the compatibility to

the cladding material, are assessed in

collaboration with the University of

Leicester. Prototype pellets of stabilized

americium oxide were synthesized

in the Minor Actinide Lab of

JRC Karlsruhe, and their stability

under a broad range of conditions

was shown. A welding methodology

for the safety encapsulation was

developed and demonstrated.

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Authors

Daniel Freis,

Jean-François Vigier,

Karin Popa,

Rudy J.M. Konings

European Commission,

Joint Research Centre – JRC,

Directorate G – Nuclear Safety &

Security

PO Box 2340,

76125 Karlsruhe, Germany

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206

SPOTLIGHT ON NUCLEAR LAW

Der lange Weg zum Endlager

Tobias Leidinger

Nach der Novelle des Standortauswahlgesetzes (StandAG) 2017 hat die Bundesgesellschaft für Endlagerung (BGE) den

Auftrag, bis 2031 einen Standort zu finden, der für eine Million Jahre Sicherheit für den Einschluss hochradioaktiver Abfälle

bietet. Aktuell befindet sich die Suche in der ersten von drei Phasen, die nach dem StandAG zu durchlaufen sind. Bereits jetzt

zeigt sich, dass der Such- und Auswahlprozess alte und neue Widerstände auslöst.

Die Suche auf der „weißen Landkarte“ – Phase 1

Die BGE hat seit 2017 für das gesamte Bundesgebiet geowissenschaftliche

Daten bei den zuständigen Bundes- und

Landesbehörden abgefragt, um sie für den Suchprozess auszuwerten.

Dieser Vorgang erwies sich als deutlich komplexer als

ursprünglich erwartet. Denn die Datenbasis in den einzelnen

Bundesländern ist durchaus unterschiedlich, Vorgaben für

eine einheitliche Bereitstellung und Aufbereitung der Daten

fehlten. Das Ziel der Endlagersuche ist es bis 2031 einen

Standort zu finden, der Sicherheit für eine Million Jahre bietet.

Bis 2050 soll das Endlager in Betrieb gehen. Dann sollen die

ca. 10.500 Tonnen hoch radioaktiver Abfälle (abgebrannte

Brennelemente, verglaste Abfälle aus der Wiederaufarbeitung

in Sellafield und La Hague) nach und nach eingelagert werden.

Derzeit lagern diese Abfälle in CASTOR®-Behältern in

Zwischenlagern.

In der zurzeit laufenden ersten Phase werden ungeeignete

Gebiete ausgeschlossen. Wird eines der sechs Ausschlusskriterien

im StandAG erfüllt, kommt eine Region oder ein Ort

als Endlager nicht mehr in Frage. Nicht geeignet für die Endlagerung

sind u.a. Gebiete, in denen zukünftig Erdbeben zu

erwarten sind oder in denen es aktive geologische Störungen

im Untergrund gibt. Positiv müssen sämtliche Mindestanforderungen

erfüllt sein, um eine prinzipielle Eignung des

geologischen Untergrundes festzustellen. Konkret bedeutet

dies, dass das zukünftige Endlager mindestens 300 Meter

Gestein von der Erdoberfläche trennen müssen, damit eine

dauerhafte Barriere gegeben ist. Eine mindestens 100 Meter

starke Schicht aus Kristallin-, Salz- oder Tongestein muss vorliegen.

Im Anschluss werden die geowissenschaftlichen

Abwägungskriterien angewandt, um besonders günstige Teilgebiete

gegenüber weniger günstigen Teilgebieten bewerten

zu können.

Im Herbst 2020, also am Ende der Phase 1, steht die

Veröffentlichung des Zwischenberichts Teilgebiete durch die

BGE an, der die Auswertung der ersten Untersuchungsphase,

d.h. eine erste Einschätzung zur weiteren Untersuchungswürdigkeit

einzelner Teilgebiete enthält. Bislang werden alle

Regionen gleich behandelt: Es gilt das Prinzip der „weißen

Landkarte“. Der Zwischenbericht Teilgebiete wird dem

Bundes amt für die Sicherheit der nuklearen Entsorgung

( BASE) übermittelt, das im Anschluss zu Teilgebietskonferenzen

einlädt, auf denen die BGE ihre Arbeitsergebnisse

präsentiert. Dort kann die Öffentlichkeit erstmals Stellungnahmen

abgeben. Anschließend löst sich die Fachkonferenz

wieder auf. Die Beratungsergebnisse der Fachkonferenzen

fließen in den Vorschlag der BGE für die übertägig zu

erkundenden Standortregionen ein.

Übertägige Erkundung – Phase 2

Nach Prüfung des Vorschlags der BGE für die Gebiete zur übertägigen

Erkundung durch das BASE übermittelt es dem BMU

den Vorschlag. Die Bundesregierung hat den Deutschen Bundestag

und den Bundesrat über die Standortregionen, die

übertägig erkundet werden sollen, zu unterrichten. Die

übertägig zu erkundenden Standortregionen bestimmt

abschließend der Bundestag durch Bundesgesetz. Auf dieser

Grundlage erkundet die BGE die Standortregionen übertägig

nach den standortbezogenen Erkundungsprogrammen.

Die BGE stellt vorläufige Sicherheitsuntersuchungen nach

Maßgabe definierter Anforderungen und Kriterien an.

Dazu gehört auch die Erstellung von sozioökonomischen

Potentialanalysen für die Standortregionen. Zum Schluss

unterbreitet die BGE begründete Vorschläge zu den untertägig

zu erkundenden Standorten, die vom BASE geprüft werden.

Anschließend werden vom BASE Erkundungsprogramme und

Prüfkriterien festgelegt. Wiederum obliegt es der Ent scheidung

von Bundestag und Bundesrat, welche Standorte letztlich

untertägig auf welche Weise erkundet werden.

Untertägige Erkundung – Phase 3

Schließlich obliegt auch die untertägige Erkundung der BGE,

wozu sie umfassende vorläufige Sicherheitsuntersuchungen

erarbeitet. Auch in dieser Phase werden die Anforderungen

und Kriterien gemäß Standortauswahlgesetz angewendet.

Ihrer Ergebnisse werden an das BASE übermittelt, woran sich

die Umweltverträglichkeitsprüfung anschließt. Das BASE

schlägt anschließend den Standort für das Endlager vor. Die

verbindliche Entscheidung wird wiederum durch Gesetz von

Bundestag und Bundesrat getroffen.

Widerstände formieren sich

Wenn bereits in 11 Jahren eine finale Entscheidung durch den

Gesetzgeber zum Endlagerstandort vorliegen soll, muss das

bis dahin zu absolvierende, 3-stufige Erkundungs- und Öffentlichkeitsbeteiligungsverfahren

reibungslos „durchlaufen“.

Fakt ist indes, dass sich bereits heute, noch vor Abschluss der

ersten Phase, alte und neue Widerstände formieren. In

Gorleben hat die Bürgerinitiative Umweltschutz Lüchow-

Dannenberg ihr eigenes „Gorleben Kapitel“ konzipiert. Auf

20 Seiten wird dargelegt, warum Gorleben im Herbst 2020

aus dem Suchverfahren endgültig ausscheiden muss. Auch in

anderen Regionen im Norden und Süden der Republik, deren

geologische Eignung als nicht offensichtlich ausgeschlossen

erscheint, formieren sich bereits Bürgerinitiativen. Ziel ist

es, frühzeitig Widerstand zu mobilisieren. Es besteht die

Befürchtung, dass das offizielle Beteiligungsverfahren zu spät

kommt, Vorentscheidungen bis dahin längst getroffen und

inhaltlicher Einfluss dann kaum noch möglich ist.

Man darf gespannt sein, ob und in welcher Weise die mit

sehr hohem Aufwand betriebene Öffentlichkeitsarbeit von

offizieller Seite einen substantiellen Beitrag zur Aufklärung

und Befriedung im Endlagersuchverfahren nach StandAG

leistet. Tatsache ist, dass das StandAG zwar detaillierte Vorgaben

für die formelle Beteiligung der Öffentlichkeit vorsieht,

das Thema „Ausgleich“ oder „Kompensation“ für die final

betroffene Region dort allerdings weder vorgesehen noch

geregelt ist. Es ist – wie bei anderen Großprojekten auch –

zweifelhaft, ob Akzeptanz allein durch Information und

Beteiligung zu erreichen ist. Viel hilft nicht automatisch viel.

Dazu bedarf es weitergehender qualitativer Instrumente und

Maßnahmen. Der Verlauf der Teilgebietskonferenzen am

Ende der Phase 1 wird ein erster Indikator dafür sein, ob das

Konzept des StandAG trägt und wie realistisch das ehrgeizige

Ziel ist, die Festlegung des Endlagerstandorts bis zum Jahr

2031 tatsächlich zu erreichen.

Author

Prof. Dr. Tobias Leidinger

Rechtsanwalt und Fachanwalt für Verwaltungsrecht

Luther Rechtsanwaltsgesellschaft

Graf-Adolf-Platz 15

40213 Düsseldorf

Spotlight on Nuclear Law

The long path to final storage ı Tobias Leidinger

atw Vol. 65 (2020) | Issue 4 ı April

Die Entsorgung von Rückbaumassen

aus kerntechnischen Anlagen –

eine rechtliche Bestandsaufnahme

Christian Raetzke

I Einführung Aufgrund des gesetzlich angeordneten Kernenergieausstiegs sind die meisten deutschen

Kernkraftwerke endgültig abgeschaltet worden; die sechs noch laufenden Anlagen sollen bis Ende 2022 folgen. Durch

den Abbau dieser Anlagen – der gem. § 7 Abs. 3 S. 4 Atomgesetz (AtG) „unverzüglich“ zu erfolgen hat, was aber einen

Zeitraum von ca. zwei Jahrzehnten umfasst – fallen erhebliche Rückbaumassen an. Nur ein kleiner Teil davon muss

als radioaktiver Abfall entsorgt werden; die ganz überwiegende Menge kann einer Entsorgung (Verwertung oder

Beseitigung) im Rahmen des Kreislaufwirtschaftsrechts zugeführt werden.

Die Entlassung dieser Reststoffe aus

dem Atom- und Strahlen schutzrecht

mittels der Instrumente „Heraus gabe“

und „Freigabe“ ist rechtlich in einer

Weise geregelt, die die Anforderungen

des Strahlenschutzes gewährleistet.

Besonders die Freigaberegelungen,

die mit der neuen Strahlenschutzverordnung

(StrlSchV) vom 29.11.2018

im Wesentlichen von der Vorgängerverordnung

über nommen, aber teils

auch ergänzt und abgewandelt

wurden, sind stark ausdifferenziert

und tragen verschie denen Reststoffund

Entsorgungskategorien Rechnung.

Interessante Fragen ergeben

sich vor allem an der Schnittstelle

zum Kreislaufwirtschaftsrecht, dem

die Reststoffe nach der Freigabe

unterfallen.

Die Entsorgung der Rückbaumassen

erweist sich allerdings auch

als ein politisch-soziales und mediales

Problem: die Rückbaumassen werden

von der Öffentlichkeit oft als gefährlich

und als „Atommüll“ angesehen,

ihre Entsorgung etwa auf Deponien

ruft Proteste und Widerstände hervor.

In diesem Aufsatz sollen die rechtlichen

Regelungen für die Entsorgung

der beim Rückbau von Kernkraftwerken

anfallenden Reststoffe – also

nicht der radioaktiven Abfälle – beleuchtet

werden. Dabei wird es auch

darum gehen, inwieweit dieser rechtliche

Rahmen bisher tatsächlich

„ gelebt“ und umgesetzt wird. Zunächst

sollen aber einige Hintergründe

zum Anfall von Reststoffen

erläutert werden.

Hintergrund und

zeitlicher Rahmen

1 Abschaltung und Rückbau

Auf die endgültige Abschaltung eines

Kernkraftwerks folgt der Rückbau der

Anlagen, sofern einzelne Gebäude

nicht nach Entlassung aus dem Atomrecht

weiter verwendet werden sollen.

Der direkte Rückbau ist für die vom

gesetzlichen Ausstieg erfassten Kernkraftwerke

seit 2017 gesetzlich vorgeschrieben:

§ 7 Abs. 3 S. 4 AtG

bestimmt, dass sie nach Beendigung

des Leistungsbetriebs „unverzüglich

stillzulegen und abzubauen“ sind. Die

damit seither ausgeschlossene Option

des sicheren Einschlusses, bei dem

das Kernkraftwerk noch Jahrzehnte

stehen bleibt und erst viel später rückgebaut

wird, hatten die Energieversorgungsunternehmen

in der Vergangenheit

aber ohnehin nur selten,

für einzelne Prototypreaktoren, gewählt;

1 für die in den letzten drei Jahrzehnten

stillgelegten Anlagen hatten

sie sich stets für den direkten Rückbau

entschieden.

Allerdings dauert es auch nach der

endgültigen Abschaltung eines Kernkraftwerks

noch lange, bis wesent liche

Rückbaumassen anfallen. Zunächst

kann es sein, dass die Anlage jahrelang

im sog. Restbetrieb gehalten werden

muss, solange keine Still legungs- und

Abbaugenehmigung (SAG) vorliegt;

das war das Schicksal der acht „Moratoriumsanlagen“

nach 2011 (siehe

unten). Nach Vorliegen der (ersten)

SAG kann mit dem eigentlichen Rückbau

begonnen werden. Dabei findet

ein Rückbau „von innen nach außen“

statt. Zunächst werden die Systeme

und Komponenten des Reaktors,

wie etwa Kerngerüst, Reaktordruckbehälter,

Rohrleitungen, Pumpen etc.

ausgebaut. Diese Arbeiten dauern

lange, da sie aufgrund der erforderlichen

Strahlenschutzmaßnahmen

zum Teil sehr anspruchsvoll sind, vor

allem was die Komponenten des Reaktorkerns

angeht. Die baulichen Strukturen

bleiben in der Regel in dieser

Phase erhalten; sie werden noch benötigt

(Statik, Abschirmung, gefilterte

Lüftung etc.) und selbst leergeräumte

Baulichkeiten werden ggf. anderen

rückbaubedingten Zwecken zugeführt

(so wird z. B. das Maschinenhaus

dann, wenn die Turbine entfernt ist,

oft als Lagerfläche oder für die Bearbeitung

von Reststoffen und Abfällen

verwendet). Erst in der Schlußphase,

also ab etwa anderthalb Jahrzehnten

nach Genehmigungserteilung und

dem entsprechenden Beginn der

Arbeiten, werden dann die wesentlichen

Baulichkeiten abgerissen.

Stilllegung und Abbau eines Kernkraftwerks

bedürfen der Genehmigung

nach § 7 Abs. 3 AtG. In der

Genehmigungspraxis wird nicht

zwischen „Stillegung“ und „Abbau“

unterschieden, sondern es ergehen in

der Regel mehrere „Stilllegungs- und

Abbaugenehmigungen“ (SAG). Im

Zuge zunehmender Erfahrung hat sich

dabei die Zahl der Genehmigungen

verringert. Als „klassisches“ Vorgehen

hat sich bei den acht 2011 stillgelegten

Anlagen ein zweistufiges Modell herausgebildet.

Mit der 1. SAG wird der

Abbau bestimmter Komponenten und

Systeme genehmigt; dabei werden

die Gebäude (Außenwände, Dächer,

tragende oder aussteifende Bauteile)

teils ausdrücklich ausgenommen. 2 Die

Genehmigung umfasst in der Regel

207

ENERGY POLICY, ECONOMY AND LAW

1 So etwa für das Kernkraftwerk Lingen, das 1968-1977 in Betrieb war; 2015 wurde die erste Genehmigung für den Rückbau erteilt.

2 Siehe etwa die Stilllegungs- und erste Abbaugenehmigung (1. SAG) für das Kernkraftwerk Philippsburg, Block 1 (KKP 1) der EnBW Kernkraft GmbH (EnKK)

vom 07.04.2017, S. 10 unter Ziffer 1.4; https://um.baden-wuerttemberg.de/de/umwelt-natur/kernenergie-und-radioaktivitaet/dokumente/genehmigungsverfahren/

kkp/.

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

atw Vol. 65 (2020) | Issue 4 ı April

ENERGY POLICY, ECONOMY AND LAW 208

KKW Stilllegung 1. SAG Stand Genehmigungen/Rückbau

Greifswald 1990 30.06.1995 Rückbau läuft

Würgassen 1994 14.07.1997

Mülheim-Kärlich 2000 16.07.2004

Stade 2003 07.09.2005

Obrigheim 2005 28.08.2008

Biblis A 2011 30.03.2017

Biblis B 2011 30.03.2017

auch die oben angesprochene

Nutzungsänderung von Baulichkeiten

wie dem Maschinenhaus. Mit der 2.

SAG wird der Abbau der restlichen

Systeme und Komponenten genehmigt.

Für einige der jüngsten Kernkraftwerke

ist eine einstufige, umfassende

SAG beantragt worden. 4

Gleich ob ein zweistufiger oder einstufiger

Weg beschritten wird: der

eigentliche Abriss der Gebäude fällt –

so ist es zumindest vorgesehen –

nicht mehr unter eine atomrechtliche

Genehmigung, da die Strukturen

vorher freigemessen und freigegeben,

also aus dem Atomrecht entlassen

wurden (zur Freigabe siehe unten).

Das heißt: der konventionelle Abriss

erfolgt erst nach dem Abschluss des

atomrechtlichen Genehmigungsverfahrens

und der von diesem umfassten

Rückbauschritte.

Im August 2014 wurden alle Rückbauarbeiten, für die

atomrechtliche Genehmigungen erforderlich waren,

abgeschlossen, die Gebäude des ehemaligen Kontrollbereichs

sind freigemessen und erfüllen die Voraussetzungen

für den Abriss

Abbauphasen 1a, 2a, 2b sowie 3c sind genehmigt, es

steht noch ein letzter Genehmigungsschritt 3d aus

Abbau nuklearer Systeme soll 2021 abgeschlossen sein,

konventioneller Abriss bis 2023

4. Abbaugenehmigung wurde am 14.05.2018 erteilt.

Atomrechtlicher Rückbau soll bis 2025 abgeschlossen

sein, anschließend Abriss oder Weiternutzung der

Gebäude

Neckarwestheim 1 2011 03.02.2017 Die 2. (abschließende) SAG wurde am 12.12.2019 erteilt

Brunsbüttel 2011 21.12.2018

Isar 1 2011 17.01.2017

Unterweser 2011 05.02.2018

Philippsburg 1 2011 07.04.2017 2. (abschließende) SAG beantragt

Krümmel 2011 beantragt

Grafenrheinfeld 2015 11.04.2018

Gundremmingen B 2017 19.03.2019

Philippsburg 2 2019 beantragt Antrag zielt auf eine einzige SAG

Grohnde vss. 2021 beantragt

Gundremmingen C vss. 2021 beantragt

Brokdorf vss. 2021 beantragt

Isar 2 vss. 2022 beantragt

Emsland vss. 2022 beantragt

Neckarwestheim 2 vss. 2022 beantragt Antrag zielt auf eine einzige SAG

| Die Übersicht zeigt den Stand der Genehmigungsver fahren.

Die Tabelle beruht auf Angaben, die auf den Websites der Behörden und der Betreiber abrufbar sind. Auf einen Einzelnachweis

wurde verzichtet.

2 Stand der Genehmigungsverfahren

für Stilllegungsund

Abbaugenehmigungen

Hier sollen nur kommerzielle Leistungsreaktoren,

keine Versuchs- und

Prototypreaktoren sowie Forschungsreaktoren,

berücksichtigt werden.

Die Anlagen, die heute rückgebaut

werden bzw. zum Rückbau an stehen,

lassen sich der besseren Übersicht

halber in drei Gruppen einteilen:

p Anlagen, die vor 2011 stillgelegt

wurden. In den Zeitraum ab 1990

fallen die ersten Stilllegungen

großmaßstäblicher Anlagen, aus

jeweils unterschiedlichen Gründen:

Greifswald 1990 (Stilllegung kraft

Einigungsvertrags), Würgassen

1994 (technische Probleme und

wirtschaftliche Erwägungen), Mülheim-

Kärlich 2000 (Genehmigung

aufgehoben durch Gerichtsurteil

von 1988, letzt instanzlich bestätigt

1998), Stade 2003 und Obrigheim

2005 (jeweils im Zusammenhang

mit der Atomausstiegs novelle

2002). Der Rückbau dieser Anlagen

läuft seit vielen Jahren, mit

unterschied lichem Fortschritt; teilweise

sind hier auch bereits

beträcht liche Rückbaumassen angefallen.

p Die sog. Moratoriumsanlagen:

acht Kernkraftwerke, die nach dem

Reaktorunfall von Fukushima im

März 2011 zunächst vorübergehend

und dann, ohne noch einmal

in Betrieb gegangen zu sein, aufgrund

der 13. AtG-Novelle vom

31. Juli 2011 endgültig stillgelegt

wurden. Nach dieser plötzlichen

Stilllegung mussten erst einmal

Anträge auf Stilllegungs- und

Abbaugenehmigungen vorbereitet

und gestellt und von den Behörden

bewältigt werden; die entsprechenden

Genehmigungen wurden

deshalb erst 2017/2018 erteilt;

eine Geneh migung (Krümmel)

steht noch aus. Daraus erklärt sich,

dass der Rückbau dieser Anlagen

erst in der Anfangsphase ist.

p Die restlichen neun Kernkraftwerke,

die spätestens zu den in

der 13. AtG-Novelle festgesetzten

Terminen (beginnend mit Grafenrheinfeld

2015) abgeschaltet werden

mussten bzw. noch müssen

(Endtermin für die letzten Anlagen

2022).

Wie bereits erwähnt, erfolgt der

eigentliche Abriss der wesentlichen

Baustrukturen erst etwa anderthalb

Jahrzehnte nach Erteilung der Genehmigung.

Aus der Übersicht folgt

daher, dass zwar bereits jetzt Rückbaumassen

zur Entsorgung angefallen

sind und laufend und mit steigender

Tendenz anfallen, dass aber die

wesent lichen Stoffströme aus dem

Rückbau, insbesondere aus dem Abriss

der Gebäude, erst bevorstehen

und im weiteren Verlauf der 2020er

und in den 2030er Jahren bewältigt

werden müssen.

3 Welche Rückbaumassen

fallen an?

Unter Verwendung der zu einzelnen

Kraftwerken von den Betreibern oder

Aufsichtsbehörden veröffentlichten

Zahlen, die einer teils unterschiedlichen

Systematik folgen, können für

3 Erstes und bislang einziges Beispiel für die 2011 stillgelegten Moratoriumsanlagen ist die Zweite Abbaugenehmigung für das Kernkraftwerk Neckarwestheim, Block I

(GKN I) der EnBW Kernkraft GmbH (EnKK) vom 12.12.2019; https://um.baden-wuerttemberg.de/de/umwelt-natur/kernenergie-und-radioaktivitaet/dokumente/

genehmigungsverfahren/gkn/.

4 Siehe etwa den Antrag vom 18. Juli 2016 für das Kernkraftwerk Neckarwestheim II; https://um.baden-wuerttemberg.de/fileadmin/redaktion/m-um/intern/Dateien/

Dokumente/3_Umwelt/Kernenergie/Genehmigungsverfahren/GKN/GKN_2/160718_Genehmigungsantrag_SAG_GKN-II.pdf.

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

atw Vol. 65 (2020) | Issue 4 ı April

die Zwecke dieses Aufsatzes die

folgenden groben Mengenangaben

gemacht werden.

Die verfügbaren Angaben zur

Gesamtmasse eines Kernkraftwerks

liegen zwischen 300.000 t (Brunsbüttel

5 ) und 675.000 t (Unterweser 6 ).

Ältere und kleinere Anlagen haben

naturgemäß kleinere Massen als

jüngere und leistungsstärkere (elektrische

Leistung Brunsbüttel ca.

800 MW, Unterweser ca. 1.345 MW).

Von dieser Gesamtmasse entfallen

etwa ein Drittel bis 40 % (bei Siedewasserreaktoren

wie Brunsbüttel)

bzw. etwa 60 % oder sogar mehr (bei

Druckwasserreaktoren wie Unterweser)

auf den „nichtnuklearen“ Anlagenteil,

also den Teil, der keinen

Kontrollbereich darstellt und bei dem

die Komponenten und Gebäude in der

Regel dem Verfahren der Herausgabe

unterliegen und somit ohne Einschränkungen

der Kreislaufwirtschaft

zugeführt werden (siehe unten).

Für die Massen aus dem Kontrollbereich

dagegen gilt:

p 2-3 % (also 1-2 % der Gesamt masse

des Kernkraftwerks) müssen als

radioaktive Abfälle entsorgt werden

(in absoluten Zahlen etwa beim

Kernkraftwerk Unterweser: 4.200 t

von insgesamt 193.000 Gesamtmasse

Kontrollbereich).

p Etwa 90 % (Unterweser: 176.900 t)

sind Gebäudestrukturen, die nach

(spezifischer) Freigabe abgerissen

werden; der Bauschutt kann uneingeschränkt

entsorgt werden.

p Die verbleibenden etwa 6-8 %

(Unterweser: 11.900 t) werden

einer uneingeschränkten Freigabe

oder einer spezifischen Freigabe

(etwa zur Deponierung) zugeführt.

Im Ergebnis werden also 98 bis 99 %

der Rückbaumassen letztlich einer

konventionellen Entsorgung (Verwertung

oder Beseitigung) zugeführt,

nachdem sie durch Herausgabe oder

Freigabe aus dem Atomrecht entlassen

wurden. Je nach Art dieser Entlassung

(vor allem bei spezifischer

Freigabe und Freigabe im Einzelfall)

gibt es – gleichsam als „Vermächtnis“

des Atomrechts für die Reststoffe – bestimmte

Vorgaben für die Entsorgung;

das trifft aber letztlich auch nur auf

einen geringeren Teil der Stoffe zu.

Ansonsten greift das Kreislaufwirtschaftsrecht.

Das soll nunmehr im

Einzelnen dargestellt werden.

III

Rechtliche Vorgaben

1 Atom- und Strahlenschutzrecht

Nach den Vorgaben des Atom- und

Strahlenschutzrechts werden die

Weichen für die Entsorgung der beim

Rückbau anfallenden Reststoffe gestellt.

a) Überblick

Ein kleiner Teil der beim Rückbau anfallenden

Stoffe muss den Vorgaben

des § 9a AtG entsprechend als radioaktiver

Abfall entsorgt werden. Das

Atomrecht verlangt, dass radioaktive

Abfälle konditioniert (bearbeitet und

verpackt) und zwischengelagert

werden, bis sie an ein Bundesendlager

abgeliefert werden. Das hierfür – es

handelt sich hier um schwach- bis

höchstens mittelaktive Abfälle – vorgesehene

Endlager ist das Endlager

Schacht Konrad, das sich in der

Errichtungsphase befindet und angabegemäß

2027 in Betrieb gehen

soll. Für die Zwischenlagerung übergeben

die Kernkraftwerksbetreiber im

Normal fall die konditionierten Abfälle

an die bundeseigene BGZ ( Gesellschaft

für Zwischenlagerung mbH), die

die Standort-Zwischen lager von den

Betreibern über nommen hat (siehe

dazu §§ 2 und 3 Entsorgungsübergangsgesetz).

Der Weg der radioaktiven

Abfälle ist somit klar vorgezeichnet

und findet komplett außerhalb

der konventio nellen Kreislaufwirtschaft

statt. Er wird in diesem

Aufsatz nicht weiter behandelt.

Die allermeisten beim Rückbau

anfallenden Reststoffe werden, wie

oben dargestellt, aus der atomrechtlichen

Überwachung entlassen. Sofern

sie nicht (ausnahmsweise) wiederverwendet

werden, werden sie

einer „konventionellen“ Entsorgung

nach dem Kreislaufwirtschaftsrecht

zugeführt.

Die Instrumente zur Entlassung

von Stoffen aus der atomrechtlichen

Überwachung sind die Herausgabe

und die Freigabe.

b) Herausgabe

Die Herausgabe ist im Stilllegungsleitfaden

von 2016 geregelt. 7

Sie

betrifft diejenigen Bereiche der

Anlage und des Anlagengeländes,

die nicht zum Kontrollbereich (vgl.

§ 52 Abs. 2 StrlSchV) gehörten bzw.

gehören, also – grob gesagt – nicht

zu dem Teil der Anlage, in dem die

Kernspaltung stattfand oder der mit

radioaktiven Stoffen in Berührung

gekommen ist. Das betrifft (wie

oben erwähnt) etwa 40-60 % der

Gesamtanlage; der Bereich umfasst

etwa Verwaltungs gebäude, die

Kantine, das Informationszentrum,

Hilfsgebäude, den Generator, bei

Druckwasserreaktoren auch das

Maschinenhaus mit Turbine. Aufgrund

der fehlenden Berührung mit

radioaktiven Stoffen, die mit dem

Reaktorbetrieb zu tun hatten, und

aufgrund des Umstandes, dass sie

keiner relevanten Direktstrahlung aus

dem Reaktor ausgesetzt waren,

können diese Anlagenteile und Gebäude

von vornherein nicht dadurch

aktiviert oder kontaminiert sein und

es wäre sinnlos, für diese Rückbaumassen

eine Freimessung jeder

anfallenden Reststoffcharge durchzuführen.

Voraussetzung ist aber, dass der

Betreiber diesen „unberührten“ Status

nachweist, indem er die Betriebshistorie

der betroffenen Bereiche

lückenlos darlegt und diese Darlegung

mit Beweissicherungsmessungen

unterfüttert. Dabei spielt auch die

Abgrenzung von nicht reaktorbedingten

und nicht der behördlichen

Kontrolle unterliegenden Kontaminationen

aus dem Fallout von Atomwaffenversuchen

oder dem Reaktorunfall

von Tschernobyl eine Rolle. 8

Das Verfahren ist im Detail nicht im

Regelwerk festgelegt; es wird von der

Behörde in einem Bescheid (meist in

einer SAG) konkret festgelegt. 9

Die

Behördenpraxis ist hinsichtlich der

Kontroll- und Anforderungsdichte

dabei offenbar nicht einheitlich.

Nach Durchführung des jeweils

bestimmten Verfahrens für einzelne

Anlagenbereiche endet die atomrechtliche

Aufsicht, ohne dass es einer

Freigabe bedarf. 10

ENERGY POLICY, ECONOMY AND LAW 209

5 Vattenfall Europe Nuclear Energy GmbH, Kurzbeschreibung für den Abbau des KKB, S. 19; https://www.schleswig-holstein.de/DE/Fachinhalte/A/atomausstieg/

Downloads/kurzbeschreibungStilllegungAbbau.html.

6 https://www.preussenelektra.de/content/dam/revu-global/preussenelektra/documents/UnsereKraftwerke/Unterweser/unsere_kraftwerkeunterweserkkuinfotagposter.pdf.

7 Leitfaden zur Stilllegung, zum sicheren Einschluss und zum Abbau von Anlagen oder Anlagenteilen nach § 7 des Atomgesetzes vom 23. Juni 2016, BAnz AT

19.07.2016 B7, Ziff. 6.4.

8 Entsorgungskommission (ESK), Freigabe radioaktiver Stoffe und Herausgabe nicht radioaktiver Stoffe aus dem Abbau von Kernkraftwerken, Informationspapier vom

16.07.2018, Langfassung, S. 18; http://www.entsorgungskommission.de/sites/default/files/reports/Informationspapier_ESK67_16072018_hp.pdf.

9 Dazu Niehaus, Entlassung von Gegenständen aus der atomrechtlichen Überwachung bei Kernkraftwerken, in: Burgi (Hrsg.), 15. Deutsches Atomrechtssymposium,

2019, S. 247 (257).

10 Stilllegungsleitfaden (Fn. 7), Ziff. 6.4, S. 15.

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atw Vol. 65 (2020) | Issue 4 ı April

ENERGY POLICY, ECONOMY AND LAW 210

c) Freigabe

aa) Grundlagen

Bei Reststoffen, die beim Rückbau

eines Kontrollbereichs anfallen, wird

im Grundsatz angenommen, dass sie

kontaminiert oder aktiviert sein

können (vgl. § 31 Abs. 1 StrlSchV); sie

werden daher zunächst als radioaktive

Stoffe im Rechtssinne (§ 2 AtG,

§ 3 StrlSchG) behandelt. Bei einem

Teil dieser Reststoffe bleibt das auch

so: sie müssen aufgrund ihrer Aktivität

als radioaktiver Abfall gem. § 9a

AtG entsorgt werden (siehe oben).

Diejenigen Reststoffe aus dem Kontrollbereich,

die tatsächlich nicht oder

nicht in relevantem Maße aktiviert

oder kontaminiert sind oder bei denen

eine vorhandene Kontamination entfernt

oder auf ein unbeachtliches

Niveau reduziert wurde, können dagegen

aus dem Atomrecht entlassen

werden. Das Instrument hierfür ist die

Freigabe.

Das System der Freigabe und die

Festlegung der Freigabewerte beruht

auf dem international anerkannten

Zehn-Mikrosievert-Konzept. Durch

die Entlassung einer Reststoffgruppe

aus der atomrechtlichen Überwachung

und ihren anschließenden

Weg außerhalb des Atomrechts darf

für Einzelpersonen der Bevölkerung

höchstens eine Jahresdosis im Bereich

von zehn Mikrosievert auftreten;

dieses Dosiskriterium ist in § 31 Abs. 2

StrlSchV festgeschrieben. Jeder

Mensch in Deutschland ist einer

natürlichen Strahlenbelastung von

durchschnittlich gut zwei Millisievert

(also gut zweitausend Mikrosievert)

ausgesetzt, wobei dieser Wert abhängig

von Faktoren wie Wohnort,

Beruf, Anzahl der Flugreisen etc.

individuell schwankt, ohne dass dies

Anlass zu Bedenken gibt. 11 Vor diesem

Hintergrund wird die Größenordnung

von zehn Mikrosievert vom Verordnungsgeber

zu Recht als vernachlässigbar

eingestuft, als ein Wert, der

eine strahlenschutzrechtliche Überwachung

nicht mehr rechtfertigt. 12

Wenn die Aktivität eines Reststoffes

nicht zu einer Überschreitung dieses

Dosiskriteriums führt, kann die Aktivität

im Rechtssinne „außer Acht

gelassen“ werden und es handelt sich

nicht (mehr) um einen radioaktiven

Stoff (§ 2 Abs. 1 S. 1 i.V.m. Abs. 2 S. 1

AtG; gleichlautend § 3 Abs. 1 S. 1 und

Abs. 2 S. 1 StrlSchG).

Die Freigabe ist im Einzelnen in

§§ 31-42 StrlSchV geregelt. Rechtlich

gesehen ist die Freigabe der

Verwaltungsakt (der Freigabebescheid,

vgl. § 33 Abs. 2 StrlSchV), in

dem die Behörde die Freigabewerte

(die allerdings weitgehend in Anlage

4 der StrlSchV vorgegeben sind) und

Details zum Verfahren für den Betreiber

verbindlich festschreibt. Dabei

geht es im Freigabebescheid in der

Regel nicht darum, eine konkrete

Reststoffcharge freizugeben. Der Freigabebescheid

trifft vielmehr eine

abstrakte Regelung, anhand derer

dann die einzelnen Reststoffchargen

vom Betreiber „freigemessen“ werden.

Die „Freimessung“ ist der Vollzug

der Freigabe, bezogen auf die jeweilige

Reststoffcharge.

Die Wirkung der Freigabe – die Entlassung

der Reststoffe aus dem Atomrecht

– tritt nach dem Grundkonzept

der StrlSchV, wie es aus § 42 Abs. 1

und 2 StrlSchV hervorgeht, dann ein,

wenn der Genehmigungs inhaber, also

der Strahlenschutzverantwortliche –

in der Praxis vertreten durch den

Strahlenschutzbeauf tragten – eigenverantwortlich

die Übereinstimmung

der Freimessung mit dem Inhalt des

Freigabebe scheides feststellt, ggf.

unter Aufsicht des behördlich bestellten

Sachverständigen, und diese Feststellung

dokumentiert. Allerdings ist

in den Freigabebescheiden oft in einer

Nebenbestimmung festgehalten, dass

die Behörde erst eine Bestätigung für

jede Freimesskampagne erteilen muss,

damit diese Wirkung eintritt. Die Möglichkeit

einer solchen aufschiebenden

Bedingung ist jetzt in § 33 Abs. 3

StrlSchV ausdrücklich klargestellt.

Die Behörde muss aber eine solche

Bestimmung nicht aufnehmen.

Die StrlSchV unterscheidet drei

Arten der Freigabe: die uneingeschränkte

Freigabe, die spezifische

Freigabe und die Freigabe im Einzelfall.

bb) Uneingeschränkte Freigabe

Nach einer uneingeschränkten Freigabe

(§ 35 StrlSchV) – die entsprechenden

Freigabewerte sind für

die einzelnen Nuklide in Anlage 4

Tabelle 1 Spalte 3 StrlSchV enthalten

– dürfen die Reststoffe frei verwendet

werden; Vorgaben und Restriktionen

ergeben sich dann nur noch aus dem

Kreislaufwirtschaftsrecht (etwa Vorrang

der Verwertung vor der Beseitigung

oder bestimmte Anforderungen

an Abfälle, die schädliche Stoffe wie

PCB oder Asbest enthalten).

cc) Spezifische Freigabe

Eine spezifische Freigabe (§ 36

StrlSchV) ist nach der Systematik der

StrlSchV vorgesehen für Stoffe, die

bestimmte Eigenschaften aufweisen

oder einer bestimmten Verwertung

oder Beseitigung zugeführt werden

sollen. Die Freigabewerte sind in

Anlage 4 Tabelle 1 StrlSchV nach den

verschiedenen in § 36 StrlSchV aufgeführten

Konstellationen enthalten.

Sie sind in der Regel höher (also

weniger anspruchsvoll) als bei der

uneingeschränkten Freigabe, weil der

generelle Nachweis für die Einhaltung

des Dosiskriteriums eben nicht abdeckend

für alle denkbaren Stoffe und

Weiterverwendungen geführt werden

muss, sondern nur für bestimmte

Stoffe und meist einen bestimmten

Entsorgungsweg.

Für den Rückbau von Gebäuden

und den dabei entstehenden Bauschutt

gibt es drei relevante Arten der

spezifischen Freigabe.

p Freigabe von Gebäuden zum Abriss

(§ 36 Abs. 1 Nr. 6 StrlSchV). Hier

erfolgt die Freimessung an der

stehenden Struktur. Nach Vollzug

der Frei gabe wird das Gebäude

konventionell abgerissen, für den

Bauschutt gibt es keine Vorgaben

mehr aus dem Strahlenschutzrecht.

p Freigabe von Bauschutt bei einer

zu erwartenden Masse von mehr

als 1.000 t im Jahr (§ 36 Abs. 1

Nr. 1 StrlSchV). Wie sich aus

Anlage 8 Teil F StrlSchV ergibt, ist

diese Freigabeoption subsidiär: sie

gilt für Bauschutt aus Abriss nur,

wenn die Voraus setzungen für eine

Freimessung an der stehenden

Struktur nicht erfüllt sind.

p Freigabe von festen Stoffen zur

Beseitigung auf Deponien (§ 36

Abs. 1 Nr. 3 StrlSchV). Dies ist eine

von mehreren Fällen der spezifischen

Freigabe, in denen die Freigabe

davon abhängig ist, dass ein

bestimmter Entsorgungsweg (hier:

die Deponierung) gewählt wird

und bestimmten An forderungen

genügt. Die besonderen Anforderungen

an Deponien enthält

Anlage 8 Teil C Ziff. 3 StrlSchV. Es

sind zwei: die Deponie muss den

Deponieklassen I, II, III oder IV der

Deponieverordnung entsprechen

und eine Jahreskapazität von mindestens

10.000 t oder 7.600 m 3 für

die eingelagerte Menge von

Abfällen, gemittelt über die letzten

drei Jahre, aufweisen.

Sofern ein bestimmter Entsorgungsweg

vorgegeben ist, hat das

Auswirkungen auf die Schnittstelle

11 Dazu etwa ESK (Fn. 8), S. 2 f.

12 Siehe die amtliche Begründung zur Strahlenschutzverordnung, BR-Drs. 423/18 vom 05.09.2018, S. 363.

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atw Vol. 65 (2020) | Issue 4 ı April

zum konventionellen Abfallrecht

( dazu siehe unten).

dd) Freigabe im Einzelfall

Die Freigabewerte für die uneingeschränkte

und für die spezifische

Freigabe sind für fast alle relevanten

Nuklide in Anlage 4 StrlSchV festgelegt;

sie beruhen auf abstraktgenerellen

Berechnungen, die abdeckend

für alle jeweils in Frage

kommenden Varianten der Weiterverwendung,

Verwertung oder Beseitigung

angestellt wurden. In Fällen, in

denen diese generellen Vorgaben

nicht greifen (etwa weil ein bestimmter

Entsorgungsweg bei der spezifischen

Freigabe nicht berücksichtigt

wurde oder weil für ein bestimmtes

Radionuklid kein Freigabewert festgelegt

wurde), kann der Betreiber die

Freigabe im Einzelfall (§ 37 StrlSchV)

beantragen. Hier muss er durch eine

auf die spezielle Situation bezogene

Berechnung darlegen, dass für die

betroffenen Reststoffe das Dosiskriterium

„im Bereich von 10 Mikrosievert

im Kalenderjahr“ aus § 31

Abs. 2 StrlSchV entweder für alle

möglichen künftigen Nutzungen, Verwendungen

etc. eingehalten ist (das

ist die ausdrücklich in § 32 Abs. 4

StrlSchV geregelte Freigabe im Einzelfall

als uneingeschränkte Freigabe)

oder dass das Dosiskriterium – analog

zur spezifischen Freigabe – bei einem

konkret vorgesehenen Verwertungsoder

Beseitigungsweg eingehalten

wird.

Für Bauschutt aus Kernkraftwerken

könnte die Freigabe im Einzelfall

etwa relevant werden, wenn

die Einlagerung auf einer Deponie

geplant wird, die die Voraussetzungen

in Anlage 8 Teil C StrlSchV nicht

erfüllt, oder wenn der Bauschutt als

Bergversatz (siehe unten) verwendet

werden soll.

2 Schnittstelle von Atomrecht

und Kreislaufwirtschaftsrecht

Wie bereits dargestellt, richtet sich die

Entsorgung (Verwertung oder Beseitigung)

von Reststoffen, die durch Herausgabe

oder Freigabe aus dem Atomrecht

entlassen wurden, nach dem

Kreislaufwirtschaftsgesetz (KrWG).

Das ist im Prinzip klar und einfach.

Höchst interessante und durchaus

praxisrelevante Rechtsfragen ergeben

sich aber für Fälle der spezifischen

Freigabe aus dem Umstand, dass die

betreffenden Stoffe und Gegenstände

einerseits freigegeben und damit aus

dem Atomrecht entlassen sind, dass

das Atomrecht ihnen andererseits

aber noch gleichsam ein „Vermächtnis“,

nämlich die Bestimmung für eine

spezifische Entsorgungsart, in ihr neues

Dasein unter dem Kreislaufwirtschaftsrecht

„mitgegeben“ hat.

Hierfür trifft § 11 Abs. 3 AtG (die

Norm ist in § 68 Abs. 2 StrlSchG im

Wesentlichen wörtlich aufgegriffen)

eine Regelung. Er bestimmt für die

Fälle, in denen – wie hier – die Freigabe

eine Beseitigung der betreffenden

Stoffe nach den Vorschriften des

KrWG vorsieht, dass die Stoffe nach

dem KrWG nicht wieder verwendet

oder verwertet werden dürfen. Hintergrund

ist, dass das KrWG zwischen

Abfällen zur Verwertung und Abfällen

zur Beseitigung unterscheidet und der

Verwertung grundsätzlich den Vorrang

einräumt (§ 7 Abs. 2 KrWG). 13

Diese Bewertung und Vorrangregelung

darf natürlich dann nicht vorgenommen

werden, wenn Stoffe vom

Atomrecht ans Kreislaufwirtschaftsrecht

mit der – strahlenschutzrechtlich

begründeten – Maßgabe übergeben

werden, sie auf einem bestimmten

Wege zu entsorgen. Das Kreislaufwirtschaftsrecht

muss sich dann an

diese Vorgabe halten.

Auch § 40 StrlSchV regelt die

Schnittstelle zwischen Strahlenschutzrecht

und Abfallrecht bei der

spezifischen Freigabe, die auf ein bestimmtes

Entsorgungsziel gerichtet

ist. Hiernach dürfen bei der nach

StrlSchV zuständigen Behörde keine

Bedenken hinsichtlich der abfallrechtlichen

Zulässigkeit des vorgesehenen

Verwertungs- oder Beseitigungsweges

bestehen; die abfallrechtlich für die

jeweils vorgesehene Verwertungsoder

Beseitigungsanlage zuständige

Behörde ist zu informieren und kann

sich in das Verfahren einschalten.

Interessant und vieldiskutiert ist

der denkbare Fall, dass Reststoffe

zwar im Einklang mit diesen Vorschriften

spezifisch freigegeben wurden,

aber dann aufgrund des Eintritts

außergewöhnlicher Umstände ihr

Entsorgungsziel nicht erreichen. Das

wäre zum Beispiel der Fall, wenn Bauschutt

zur Deponierung freigegeben

wurde, die betreffende Deponie aber

kurzfristig geschlossen wird oder den

Bauschutt doch nicht annimmt. Die

neue Regelung in § 33 Abs. 4 StrlSchV,

wonach der Freigabebescheid (unter

anderem) mit einem Widerrufs- oder

Auflagenvorbehalt versehen werden

kann, beruht auf solchen Überlegungen.

Das geht aus der Begründung zur

StrlSchV hervor: wenn sich herausstelle,

dass die „Freigabe nicht erfolgreich

durchgeführt werden“ könne,

müssten die freigegebenen Stoffe wieder

der atom- und strahlenschutzrechtlichen

Aufsicht unterworfen

werden. 14 Das soll durch den Widerrufsvorbehalt

ermöglicht werden.

Richtig ist, dass sich die Stoffe nach

der Freigabe und vor dem Erreichen

des Entsorgungszieles in einer Art

Zwischenzustand befinden, in dem sie

das oben schon erwähnte atomrechtliche

„Vermächtnis“ eines definierten

Entsorgungszieles mit sich tragen, das

aber nicht aus dem – jetzt eigentlich

anwendbaren – Kreislaufwirtschaftsrecht

stammt und dort nicht durchgesetzt

werden kann. Dieses Grundsatzproblem

wird durch eine mit dem neuen

Strahlenschutzrecht eingeführte

Änderung beim System der Freigabewerte

noch stärker betont: das bisherige

Prinzip der „Deckelung“, wonach

die Werte der (nach der alten StrlSchV)

zielgerichteten Freigabe niemals

höher waren als die Freigrenzen, ist

ent fallen. Da nunmehr die Werte der

uneingeschränkten Freigabe und die

abgesenkten Frei grenzen identisch

sind, können die gleichgebliebenen

Werte für die spezifische Freigabe

durchaus höher liegen als die Freigrenzen.

Der Bauschutt, der im

obigen Beispiel nicht an die Deponie

abgeliefert werden kann, könnte also

theoretisch eine Aktivität aufweisen,

die über der Freigrenze liegt. Auch aus

diesem Grund ist eine „Verlängerung“

der atomrechtlichen Aufsicht sinnvoll.

Ob der Widerruf der Freigabe in

Fällen, in denen das Entsorgungsziel

vereitelt wird, hierfür der richtige

Ansatz ist, erscheint aber zweifelhaft:

dadurch würden die Stoffe umgehend

wieder zu radioaktiven Stoffen – mit

allen (teils widersinnigen) Konsequenzen,

die sich aus dieser „Zurückverwandlung“

ergeben. 17

Plausibler

erscheint die Ansicht, dass hinsichtlich

ENERGY POLICY, ECONOMY AND LAW 211

13 Siehe die amtliche Begründung zu § 11 Abs. 3 AtG, der durch das Änderungsgesetz vom 3. Mai 2000 eingefügt wurde, BT-Drs. 14/2443, S. 12.

14 BR-Drs. 423/18, S. 372.

15 Zum Wegfall der „Deckelung“ siehe die amtliche Begründung zur StrlSchV von 2018, BR-Drs. 423/18, S. 368 und S. 500.

16 So Röller, Freigabe und Erfahrungen bei der Entsorgung freigegebener Stoffe, in: Feldmann/Raetzke/Ruttloff (Hrsg.), Atomrecht in Bewegung, 2019, S. 145 (153).

17 Kritisch zu einer solchen mehrfachen Änderung des rechtlichen Status, die der Rechtssicherheit entgegenstehe, Schirra/Nüsser, Freigabe radioaktiver Stoffe – Rechtsund

Vollzugsfragen aus Betreibersicht, in: Burgi (Hrsg.), 15. Deutsches Atomrechtssymposium, 2019, S. 265 (274 ff.), und Ulrike Feldmann, Das neue Strahlenschutzgesetz

und die Freigabe: Alles neu macht der Mai, atw 2018, S. 296 (298).

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atw Vol. 65 (2020) | Issue 4 ı April

ENERGY POLICY, ECONOMY AND LAW 212

des noch nicht erreichten Entsorgungszieles

auch ohne ausdrückliche Ermächtigung

eine weiterwirkende

Anordnungsbefugnis der strahlenschutzrechtlich

zuständigen Behörde

besteht, obwohl es sich infolge der

Freigabe nicht mehr um einen radioaktiven

Stoff handelt. 18 Dies macht den

Widerruf entbehrlich.

In jedem Falle endet die Widerrufsmöglichkeit

laut der Begründung

zur Strahlenschutzverordnung dann,

wenn „der notwendige Endpunkt der

Entsorgung … erreicht ist“ 19 , wenn

also etwa der Bauschutt in die Deponie

eingebaut wurde.

3 Kreislaufwirtschaftsrecht

Nach Freigabe bzw. Herausgabe

unterliegen die Rückbaumassen –

unter Beachtung der soeben behandelten

verbleibenden Maßgaben aus

dem Atomrecht – in vollem Umfang

dem Kreislaufwirtschaftsrecht.

Das hat im Wesentlichen zwei

Folgen. Zum einen muss der Kernkraftwerksbetreiber

die Regelungen

des Kreislaufwirtschaftsrechts beachten,

etwa den Vorrang der Verwertung

vor der Beseitigung, der bei uneingeschränkt

freigegebenen Abfällen – anders

als bei den auf einen bestimmten

Beseitigungsweg festgelegten spezifisch

freigegebenen Stoffen – voll

greift. Enthalten die Abfälle konventionelle

Schadstoffe wie Asbest oder

PCB, sind die entsprechenden Vorgaben

zur Entsorgung naturgemäß zu

beachten, die die Entsorgungsmöglichkeiten

ggf. einschränken.

Zum anderen bedeutet die

Anwendung des Kreislaufwirtschaftsrechts,

dass die örtlich zuständigen

öffentlich-rechtlichen Entsorgungsträger

– also in der Regel die Landkreise

– nach § 20 Abs. 1 KrWG

verpflichtet sind, die Reststoffe als in

ihrem Gebiet anfallende gewerbliche

Abfälle zur Beseitigung anzunehmen

und zu beseitigen. 20

Dass die Entsorgungsträger

dieser Verpflichtung

gegenwärtig nicht vollständig nachkommen,

steht auf einem anderen

Blatt; das soll unten näher ausgeführt

werden.

4 Nutzung von Bauschutt

im Bergversatz

Als weitere Entsorgungsoption wird

neuerdings die Verwertung von Bauschutt

aus Kernkraftwerken zur Verfüllung

von Bergwerken diskutiert. 21

Der Bergversatz stellt nach § 6 Abs. 1

Nr. 4 KrWG eine Abfallverwertung und

keine Abfallbeseitigung dar; Rechtsgrundlage

im Einzelnen ist die Versatzverordnung

(VersatzV). Abfallrechtlich

und bergrechtlich scheint – soweit der

Verfasser das beurteilen kann – die entsprechende

Nutzung von Bauschutt,

der einen unter den Kriterien der genannten

Rechtsgebiete offenbar eher

„unproblematischen“ mineralischen

Abfall darstellt, grundsätzlich möglich.

Insofern stellt sich die Frage nach der

Schnittstelle zum Strahlenschutzrecht.

Eine solche Schnittstelle ist mit

§ 37 Abs. 1 S. 3 StrlSchV nunmehr ausdrücklich

vorhanden. Hiernach kann

bei entsprechendem Nachweis der

Einhaltung des Dosiskriteriums die

Freigabe im Einzelfall auch erfolgen,

„soweit die Freigabe zum Einsatz in

einem Grubenbau nach § 1 Absatz 1

der Versatzverordnung“ erfolgt. Diese

Regelung wurde auf Vorschlag des

Bundesrates in den Entwurf der neuen

Strahlenschutzverordnung eingefügt.

In der Begründung heißt es, „vor

dem Hintergrund der bestehenden

Dis kussion über Unklarheiten zur

diesbezüglichen Rechtslage“ bedürfe

es der Klarstellung, dass diese „zusätzliche

Option“ zu den Entsorgungswegen

der spezifischen Freigabe zulässig

sei. Der Bundesrat führt weiter

aus:

„Die Verbringung in ein Versatzbergwerk

untertage kann einen gleichwertigen

Schutz wie die Verbringung auf

eine Deponie bieten, zumal eine zusätzliche

Abschirmung durch das Deckgebirge

erfolgt. Da der dortige Einbau

zur Sicherung von Hohlräumen erfolgt,

ist dieser schon aus bergbaulicher Sicht

abschließend und nicht reversibel.“ 22

Der letzte Satz bezieht sich offenkundig

auf die oben behandelte

Forderung in § 11 Abs. 3 AtG und § 68

Abs. 2 StrlSchG, wonach zur Beseitigung

freigegebene Stoffe nicht unter

dem Kreislaufwirtschaftsrecht wieder

verwendet oder verwertet werden

dürfen.

Insofern ist die Freigabe im Einzelfall

für die Verwertung von Bauschutt

aus Kernkraftwerken in Versatzbergwerken

grundsätzlich möglich, sofern

die Einhaltung des Dosiskriteriums

„im Bereich von zehn Mikrosievert pro

Jahr“ gem. § 31 Abs. 2 StrlSchV nachgewiesen

wird. 23

Dabei spielt auch

der Langzeitsicherheitsnachweis eine

Rolle, den die VersV bei Salzbergwerken

verlangt und der belegen

muss, dass der Betrieb und die

Nachbetriebsphase eines Bergwerks,

in das Abfälle zur Verwertung eingebracht

werden sollen, zu keiner

18 So Niehaus (Fn. 9), S. 252 f.

19 BR-Drs. 423/18, S. 372.

20 So auch Schirra/Nüsser (Fn. 17), S. 276.

21 Dazu eingehend – am Beispiel der Grube Teutschenthal in Sachsen-Anhalt – Schmidt/Versteyl, Bergversatz als langzeitsichere Alternative zur Deponierung von

„ Stilllegungsabfällen“ und Rückbaumassen kerntechnischer Anlagen in der bergbaulichen Praxis, in: Thiel/Thomé-Kozmiensky/Pretz/Senk/Wotruba (Hrsg.),

Mineralische Produkte und Nebenabfälle 6, 2019; https://www.vivis.de/2019/08/rueckbaumassen-kerntechnischer-anlagen-bergversatz-als-alternative-zuruebertaegigen-deponierung/6906.

Einen entsprechenden Vortrag hielten die Verfasser auch auf der KONTEC 2018.

22 BR-Drs. 423/18 (Beschluss), S. 5 f.

23 So dezidiert auch Schmidt/Versteyl (Fn. 21), S. 589.

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

atw Vol. 65 (2020) | Issue 4 ı April

Beeinträchtigung der Biosphäre führen

können (§ 2 Nr. 2, § 4 Abs. 3

VersV). 24

Umsetzung des

Entsorgungskonzepts

1 Einleitung

Rein rechtlich ist die Entsorgung der

Rückbaumassen aus Kernkraftwerken

ausführlich und ausreichend geregelt,

einschließlich der Pflicht der zuständigen

Entsorgungsträger, bestimmte

Abfälle aus Kernkraftwerken anzunehmen.

Wie einleitend erwähnt, wird

das auf Herausgabe und Freigabe fußende

Entsorgungskonzept jedoch in

Teilen der Medien, der Politik und der

Bevölkerung kritisiert und in Frage

gestellt; die Diskussion dreht sich meist

um die Deponierung von Bauschutt

aus Kernkraftwerken. Gegner, die der

Freigabe und kon ventionellen Entsorgung

grund sätzlich ablehnend gegenüberstehen,

fordern den gesicherten

Verbleib der Rückbaumassen auf dem

Anlagengelände („Bunker“) oder die

Errichtung eines „Endlagers“. Kommunale

Träger von Deponien lehnen teilweise

die Annahme von Bauschutt aus

kerntechnischen Anlagen ab.

2 Vorgehen in einzelnen

Bundesländern

Einige Bundesländer haben deshalb

Initiativen ergriffen, um der Bevölkerung

die Unbedenklichkeit der

konventionellen Entsorgung herausgegebener

oder freigegebener

Reststoffe aus dem Rückbau von

Kernkraftwerken zu erläutern und

ggf. durch Zusatzmaßnahmen eine

größere Akzeptanz herzustellen.

a) Baden-Württemberg

In Baden-Württemberg wurde 2015

eine „Handlungsanleitung zur Entsorgung

von freigemessenen Abfällen

auf Deponien in Baden-Württemberg“

veröffentlicht. 25

Sie entstand unter

der Federführung des Landkreistags

Baden-Württemberg und des Städtetags

Baden-Württemberg unter Mitwirkung

des Umweltministeriums.

Das Papier bezieht sich auf die

Entsorgung aller Abfälle, die gemäß

Anlage III Tabelle 1 Spalte 9a bzw.

Spalte 9c der (damaligen) Strahlenschutzverordnung

für die Beseitigung

auf Deponien freigegeben sind (S. 4),

also auf die Deponierung fester Stoffe

bis zu 100 bzw. 1.000 Tonnen pro Jahr

(das entspricht Spalten 8 und 10 in Anlage

4 Tabelle 1 der heutigen StrlSchV).

Es stellt ausdrücklich fest, dass die entsorgungspflichtigen

Deponiebetreiber

in Baden-Württemberg gesetzlich verpflichtet

sind, zur Beseitigung freigegebene

Abfälle auf den Deponien anzunehmen

und abzulagern (S. 2). Dennoch

wird zur „ Gewährleistung einer

unabhängigen zusätzlichen vollständigen

Kontrolle“ (S. 5) in der Handlungsanleitung

ein Verfahren festgelegt, das

über die Anforderungen der StrlSchV

hinausgeht. Das Papier verzichtet auf

eine ausdrückliche rechtliche Einordnung

dieser Maßnahmen, referiert

aber die (zutreffende) Rechtsansicht

der Kernanlagenbetreiber, dass es sich

um „rechtlich nicht zwingende Erweiterungen“

handele, die aber

freiwillig mitgetragen würden. Die

hauptsäch lichen Zusatzelemente sind:

p Die Freimessung wird vom

Sachverständigen der atomrechtlichen

Aufsichtsbehörde nach § 20

AtG nicht mehr nur stichprobenartig,

sondern vollständig überprüft.

p Der Sachverständige verplombt

nach der Freimessung sowohl den

Behälter als auch den Ladungsträger

für den Transport.

p Die Deponiebetreiber erhalten vom

Betreiber der kerntechnischen

Anlage die Möglichkeit, sich von

der Durchführung der o.g. Maßnahmen

zu überzeugen; sie

können einen eigenen Sachverständigen

mit stichprobenartigen

Prüfungen beauftragen.

p Weitere Maßgaben betreffen die

Protokollierung und Dokumentation

der o.g. Maßnahmen und

das tatsächliche Vorgehen bei

Anlieferung und Einbau in den

Deponien (Bündelung der Anlieferung

an wenigen Tagen,

Einbau auf einer kleinräumigen

Fläche, zeitnahe Abdeckung).

In einem zeitlichen und inhaltlichen

Zusammenhang mit der Handlungsanleitung

stand ein Gutachten,

das die Abfallwirtschaftsgesellschaft

des Neckar-Odenwald-Kreises mbH

(AWN) beim Öko-Institut in Darmstadt

in Auftrag gab; es ging um die

Bewertung der Einlagerung von Bauschutt

aus dem Kernkraftwerk Obrigheim

in einer Deponie der AWN. 26

Das Gutachten äußert sich verhalten

positiv zum Zehn-Mikrosievert-

Konzept (es begrenze mögliche

Risiken für die Bevölkerung auf ein

„sehr niedriges Niveau“) und hält die

untersuchten Elemente des Entsorgungskonzepts,

besonders auch

unter Berücksichtigung der „Handlungsanleitung“,

für belastbar.

Das Ministerium stellte flankierend

zahlreiche Informationen zur Frei ga be

bereit, unter anderem eine grafisch

aufbereitete vergleichende Darstellung

der durchschnittlichen Strahlenbelastung

aus natürlichen bzw. zivilisatorischen

Strahlenquellen in

Deutschland und des Frei gabe-Dosiskrite

riums von zehn Mikro sievert. 27

Trotz dieser aufwendigen Vorarbeiten

stellten sich Hemmnisse

und Verzögerungen bei der Entsorgung

ein. Bereits im Juni 2016

verhängte das Umweltministerium

ein Anlieferstopp auf Deponien für

freigemessene Abfälle aus dem Rückbau

kerntechnischer Anlagen. Zur

Begründung führte es aus, die Frage

der Nachnutzung von stillgelegten

Deponien mit freigemessenen Abfällen

sei bei Erlass der Strahlenschutzverordnung

nicht ausreichend

berücksichtigt worden, da es keine

entsprechenden Berechnungen gegeben

habe. 28

Nachdem das Öko-

Institut in einem vom Ministerium in

Auftrag gegebenen Gutachten 29

entsprechende

Berechnungen nachgeholt

und bestätigt hatte, dass für die

in Frage kommenden Nachnutzungen

(z. B. land- oder forstwirtschaftliche

Nutzung, Wohnbebauung oder Verkehrsflächen)

das Zehn-Mikrosievert-

Konzept eingehalten werde, hob das

Umweltministerium am 22.11.2016

die Untersagung auf. 30

ENERGY POLICY, ECONOMY AND LAW 213

24 Näher zum Langzeitsicherheitsnachweis Schmidt/Versteyl (Fn. 21), S. 582 f.

25 https://um.baden-wuerttemberg.de/fileadmin/redaktion/m-um/intern/Dateien/Dokumente/3_Umwelt/Kernenergie/Freigaben_StrlSCHVO/Handlungsanleitung_

Deponien_2015.pdf.

26 Öko-Institut e.V. (Christian Küppers unter Mitarbeit von Mathias Steinhoff), Stellungnahme zu konzeptionellen Fragen der Freigabe zur Beseitigung auf einer Deponie

bei Stilllegung und Abbau des Kernkraftwerks Obrigheim (KWO), 03.08.2015; https://um.baden-wuerttemberg.de/fileadmin/redaktion/m-um/intern/Dateien/

Dokumente/3_Umwelt/Kernenergie/Freigaben_StrlSCHVO/KWO/KWO_Deponie_bei_Stilllegung_und_Abbau.pdf.

27 Die Grafik kann auf https://um.baden-wuerttemberg.de/de/umwelt-natur/kernenergie-und-radioaktivitaet/entsorgung/freigabe/de-minimis-konzept

heruntergeladen werden.

28 https://um.baden-wuerttemberg.de/de/service/presse/pressemitteilung/pid/gutachten-belegt-unbedenklichkeit-freigemessener-abfaelle/.

29 Öko-Institut e.V. (Küppers/Claus/Ustohalova), Mögliche radiologische Folgen der Freigabe zur Beseitigung nach § 29 StrlSchV bei der Nachnutzung einer Deponie

in der Nachsorgephase und in der Zeit nach der Entlassung aus der Nachsorge, Gutachten vom 15.11.2016; https://um.baden-wuerttemberg.de/fileadmin/

redaktion/m-um/intern/Dateien/Dokumente/3_Umwelt/Kernenergie/Freigaben_StrlSCHVO/20161115_Nachnutzung_Deponie.pdf.

30 Siehe Fn. 28.

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

atw Vol. 65 (2020) | Issue 4 ı April

ENERGY POLICY, ECONOMY AND LAW 214

Kurz darauf, am 26.11.2016, verabschiedete

die Vertreterversammlung

der Landesärztekammer Baden-

Württemberg eine Entschließung 31 , in

der sie sich grundsätzlich gegen die

Freigabe von Abfällen aus dem Rückbau

kerntechnischer Anlagen aussprach

und die Verwahrung auch des

„gering strahlenden Mülls“ auf dem

Gelände des jeweiligen Kraftwerks

forderte. Die Entschließung argumentiert

damit, dass es keinen Schwellenwert

für die Unbedenklichkeit radioaktiver

Strahlung gebe und dass die

gesundheitlichen Folgen einer „Verteilung

von AKW-Rest-Müll“ nicht

geklärt seien. Eine Intervention des

Umweltministers Untersteller führte

am 15.01.2017 zu einer Pressemitteilung

32 , in der der Präsident der

Landesärztekammer gemeinsam mit

dem Minister die Gültigkeit des Zehn-

Mikrosievert-Konzepts bestätigte. Der

Vorgang wiederholte sich dann auf

Bundesebene: auf dem 120. Deutschen

Ärztetag im Mai 2017 wurde

eine Entschließung verabschiedet,

die sich im Wortlaut weitgehend an

der Erklärung der Landesärztekammer

Baden-Württemberg orientiert. 33

Nach einer erneuten Intervention von

Minister Untersteller 34 teilte der

Präsident der Bundesärztekammer

mit Schreiben vom 08.12.2017 35 einen

Vorstandsbeschluss mit, wonach die

Entschließung des 120. Deutschen

Ärztetages „nicht wissenschaftlich

haltbar“ sei. Im selben Sinne äußerte

sich auch der Fachverband für

Strahlenschutz e.V. 36

b) Schleswig-Holstein

In Schleswig-Holstein legte der damalige

Energiewendeminister Habeck

im April 2016 den Entwurf einer

Entsorgungsvereinbarung vor. 37 Nach

diesem Entwurf sollten sich die nicht

konkret genannten „Parteien“ der Vereinbarung

– wohl das Ministerium,

die Anlagenbetreiber, die öffentlichrechtlichen

Entsorgungsträger und

ausgewählte Umweltverbände – im

Grundsatz zu den bestehenden

rechtlichen Regelungen und damit

zum Freigabekonzept bekennen. Im

Gegenzug waren – im Ansatz ähnlich

wie in der baden-württembergischen

„Handlungsanleitung“ (s. o.) – bestimmte

zusätzliche Elemente vorgesehen

wie etwa die Einrichtung

einer „Begleitgruppe“ der Vertragsparteien,

der unbedingte Vorrang der

Verwertung, falls möglich, vor der

Deponierung, die individuelle Qualifizierung

aller betroffenen Deponien

durch den Gutachter des Ministeriums,

das koordinierte Vorgehen

aller Betreiber durch Errichtung einer

zentralen „gläsernen Gesellschaft“

oder die 100-prozentige Prüfung aller

Freimessungen durch den Sachverständigen

der Behörde.

Nachdem dieser Entwurf sich

offen bar als nicht konsensfähig erwiesen

hatte, rief das Ministerium

eine kleine, nicht öffentlich tagende

Arbeitsgruppe aus Umweltverbänden,

Kommunalen Spitzenverbänden, Verbänden

der Entsorgungswirtschaft

und Kraftwerksbetreibern ins Leben,

die nach insgesamt sechs Sitzungen

im Juni 2018 einen Abschlussbericht

vorlegte. 38 Dieser Bericht enthält im

Wesentlichen eine Darstellung und

Bewertung verschiedener Entsorgungskonzepte.

An mehreren Stellen

enthält der Bericht ein abweichendes

Sondervotum des BUND (als einem

von drei teilnehmenden Umweltverbänden),

wird aber ansonsten von

allen Beteiligten mitgetragen.

Das Zehn-Mikrosievert-Konzept

und die Freigabe zur Deponierung

wird im Grundsatz akzeptiert; radikal

abweichende Alternativen (sicherer

Einschluss des Kernkraftwerks, langfristige

Zwischenlagerung der Rückbaumassen

auf dem Kraftwerksgelände

oder Errichtung eines „Endlagers“

für die Rückbaumassen)

werden letztlich abgelehnt. Für die

Deponierung nicht verwertbarer

Rückbaumassen, die somit grundsätzlich

bejaht wird, werden wiederum

verschiedene Varianten bewertet. Als

„Nullvariante“ wird die Nutzung

bestehender Deponien nach den

rechtlichen Vorgaben des Kreislaufwirtschafts-

und des Strahlenschutzrechts

erörtert und grundsätzlich

befürwortet. Für den Fall, dass

sich hierfür keine Deponiebetreiber

finden, wird als „Rückfallvariante“

eine Zuweisung durch die zuständigen

Behörden als ultima ratio vom

Ministerium eingebracht. Umgekehrt

wird mit „Deponie plus“ ein Konzept

vorgestellt, das mit Zusatzmaßnahmen

wie den oben bereits dargestellten

(etwa Qualifizierung der

einzelnen Deponien etc.) die Akzeptanz

fördern soll; diese Variante wird

letztlich als bevorzugte Variante bezeichnet.

Dementsprechend kündigt

das Ministerium in dem Bericht an,

eine Qualifizierung aller in Betracht

kommenden Deponien und, falls

möglich, ein Ranking vorzunehmen.

Am 9. September 2019 stellte der

neue Minister Albrecht das Ergebnis

eines entsprechenden Gutachtens des

TÜV Nord vom 16.08.2019 vor. 39 Der

TÜV stufte alle sieben untersuchten

Deponien als geeignet ein. Das

Ministerium empfahl jedoch, für die

Ablagerung der Abfälle nur vier der

sieben Deponien weiterzuverfolgen, da

die drei übrigen Deponien kurz vor der

endgültigen Verfüllung stünden und

nicht mehr die nötige Kapazität aufwiesen.

Eine Rangfolge unter den vier

verbleibenden Deponien wurde nicht

aufgestellt. Im Übrigen betonte das

Ministerium, für die Entsorgung müssten

die Betreiber und Ent sor gungsträger

Vereinbarungen abschließen;

das Ministerium werde diesen Vorgang

„ergebnisorientiert begleiten“.

Dass damit der Konflikt nicht gelöst

ist, zeigt ein Beschluss der Bürgerschaft

der Hansestadt Lübeck vom

28.11.2019, in dem die Einlagerung

freigegebener Abfälle aus dem Abriss

von Kernkraftwerken auf der Deponie

Lübeck-Niemark (einer der vier

empfohlenen Deponien) abgelehnt

wird. 40

31 https://www.aerztekammer-bw.de/10aerzte/05kammern/10laekbw/20ehrenamt/16entschliessungen/20161126/522.html.

32 https://www.aerztekammer-bw.de/news/2017/2017-01/gemeinsame-pm/index.html.

33 Beschluss Ib-111 „Keine Freigabe gering radioaktiven Atommülls“, Beschlußprotokoll des 120. Deutschen Ärztetages, S. 240; https://www.bundesaerztekammer.de/

fileadmin/user_upload/downloads/pdf-Ordner/120.DAET/120DaetBeschlussProt_2017-05-26.pdf.

34 https://um.baden-wuerttemberg.de/fileadmin/redaktion/m-um/intern/Dateien/Dokumente/3_Umwelt/Kernenergie/Freigaben_StrlSCHVO/170807_Untersteller_

Schreiben_an_Montgomery.pdf.

35 https://um.baden-wuerttemberg.de/fileadmin/redaktion/m-um/intern/Dateien/Dokumente/3_Umwelt/Kernenergie/Freigaben_StrlSCHVO/171208_Montgomery_

Schreiben_Vorstandsbeschluss.pdf.

36 Stellungnahme des Fachverbands für Strahlenschutz e.V. vom 29.10.2017, https://fs-ev.org/fileadmin/user_upload/Deutscher_AErztetag_171029.pdf.

37 Vereinbarung zur ortsnahen Verwertung und Beseitigung von Abfällen mit keiner oder zu vernachlässigender Aktivität aus kerntechnischen Anlagen, Stand

27.04.2016; auf der Website des Ministeriums nicht mehr eingestellt.

38 AG Entsorgung freigegebener Abfälle, Entsorgung freigegebener Abfälle aus Kernkraftwerken – Abschlussbericht –,

https://www.schleswig-holstein.de/DE/Fachinhalte/A/atomausstieg/Downloads/abschlussbericht2018.pdf?__blob=publicationFile&v=1.

39 Siehe die Darstellung auf der Website des MELUND unter https://www.schleswig-holstein.de/DE/Fachinhalte/A/atomausstieg/faqEntsorgungsvereinbarung.html.,

dort unter Frage 16. Das Gutachten des TÜV Nord ist auch verfügbar unter https://www.schleswig-holstein.de/DE/Landesregierung/V/_startseite/Artikel2019/

III/190909_Deponie_gutachten/190909_GutachtenDeponien.pdf.

40 Vorlage 2019/08174-01-01; https://www.luebeck.de/de/rathaus/politik/pil/bi/vo020.asp?VOLFDNR=1008376#allrisBV.

Energy Policy, Economy and Law

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atw Vol. 65 (2020) | Issue 4 ı April

c) Niedersachsen

In einer Antwort auf eine mündliche

Anfrage im niedersächsischen Landtag

2015 41

verwies der damalige

Umweltminister Wenzel auf die Pflicht

der örtlich zuständigen öffentlichrechtlichen

Entsorgungsträger, also

im Wesentlichen der Landkreise, den

Bauschutt aus Kernkraftwerken anzunehmen.

Systematische Bemühungen

wie in Baden-Württemberg und in

Schleswig-Holstein, die Beteiligten –

ggf. unter Zugeständnissen in Form

zusätzlicher Kontroll- und Sicherheitsmaßnahmen

– zu einem Konsens

über die Entsorgung zu bewegen, sind

aus Niedersachsen bislang nicht bekannt

geworden.

d) Sachsen

Der Blick auf den Freistaat Sachsen

öffnet eine andere Perspektive:

Sachsen hat selbst keine Kernkraftwerke,

war jedoch „Empfängerland“

für Bauschutt. Die StrlSchV sieht

ausdrücklich die Möglichkeit einer

Verwertung bzw. Beseitigung freigegebener

Reststoffe in einem

anderen Bundesland vor; §§ 39 und

40 StrlSchV enthalten entsprechende

Vorgaben zur Abstimmung zwischen

den beteiligten Behörden. Bauschutt

aus dem KKW Stade in Niedersachsen

sollte auf Grundlage entsprechender

privatrechtlicher Verträge ab 2014

auf zwei sächsischen Deponien

entsorgt werden; das sächsische Umweltministerium

hatte nach dem (damaligen)

§ 29 Abs. 2 S. 6 StrlSchV

(heute § 39 Abs. 1 StrlSchV) das Einvernehmen

erteilt. 42

Daraufhin kam

es jedoch zu örtlichen Protesten, die

trotz einer Transparenzoffensive des

sächsischen Ministeriums anhielten. 43

Letztlich verzichteten die beteiligten

Deponien 2015 auf eine Verlängerung

der Verträge. 44

In diesem Zusammenhang wurde

auch thematisiert, ob es eine Verpflichtung

gibt, Rückbaumassen im

eigenen Bundesland zu entsorgen.

Dass die StrlSchV Regelungen gerade

für die länderübergreifende Entsorgung

trifft, ist bereits erwähnt worden;

eine Rechtspflicht zur Entsorgung

im eigenen Bundesland gibt es

daher eindeutig nicht. Von Sachsen

wurde jedoch geltend gemacht, auf

der 83. Umweltministerkonferenz am

24. Oktober 2014 in Heidelberg hätten

sich die Umweltminister auf einen

entsprechenden politischen Grundsatz

geeinigt. 45 Das wird aus anderen

Bundesländern bisher nicht bestätigt.

Der „Abschlussbericht“ aus Schleswig-

Holstein von 2018 kennt eine solche

Vereinbarung nicht, kommt hinsichtlich

des Verbringens in andere Bundesländer

aber zu einer abgewogenen

Bewertung: Rechtlich stehe es den

Betreibern der kerntechnischen

Anlagen in jedem Fall frei, auch

Deponien außerhalb Schleswig-

Holsteins zu nutzen, soweit sich hier

annahmebereite Deponien fänden;

da an solchen Standorten aber

möglicher weise die lokale Akzeptanz

durch die Empfindung gemindert

würde, hier wolle ein anderes Bundesland

sein Entsorgungsproblem abwälzen,

sei dies „keine primäre Option“. 46

3 Bewertung und Ausblick

Die rechtlich bestehende Annahmepflicht

der zuständigen und geeigneten

Deponien öffentlich-rechtlicher

Entsorgungsträger ist von den Aufsichtsbehörden

bislang nicht gegen

örtlichen Widerstand durchgesetzt

worden. Eine Vollziehung des geltenden

Rechts in dieser Hinsicht als

ultima ratio könnte sich letztlich

als unumgänglich herausstellen. 47

Allerdings ist es auch eine empirische

Tatsache, dass politische Entscheidungsträger

sich schwertun, eine

Einlagerung gegen den Widerstand

der örtlichen Bevölkerung und der

jeweiligen Kommunen durchzusetzen.

Natürlich ist es wünschenswert,

dass es gelänge, eine weitgehende

Akzeptanz seitens der Bevölkerung

und der Kommunen herzustellen.

Klare und transparente Information,

wie sie in vielen Fällen von Kernkraftwerksbetreibern

und Behörden zur

Verfügung gestellt wird, ist hierfür ein

wichtiger Baustein. Das Ziel, Akzeptanz

zu gewinnen, liegt auch dem

Ansatz der baden-württembergischen

„Handlungsanleitung“ und der Vorzugsvariante

„Deponie plus“ des

„ Abschlussberichts“ aus Schleswig-

Holstein zugrunde: durch zusätzliche

Kontroll- und Sicherungsmaßnahmen

soll das Vertrauen in den Freigabeprozess

und damit auch die Akzeptanz

der Entsorgung freigegebener Abfälle

auf Deponien gestärkt werden. Grundsätzlich

ist es zu be grüßen, dass einige

Landesregierungen hier initiativ

geworden sind; auch ist der verfolgte

Ansatz aller Ehren wert. Ob er zielführend

ist, dazu stellen sich jedoch

bei näherer Betrachtung und Überlegung

und angesichts der bisherigen

Erfahrungen Zweifel ein.

Das Dilemma bei einem solchen

Vorgehen besteht zunächst unausweichlich

darin, dass damit die bestehenden

Regelungen tendenziell als

nicht ausreichend hingestellt werden.

Das ist nicht gutzuheißen, denn die

dichten und restriktiven Regelungen

der StrlSchV gewährleisten sehr wohl

die Einhaltung des Bagatellwerts von

zehn Mikrosievert, der gesundheitlich

unbedenklich ist; das ist bei den Vorarbeiten

zur Strahlenschutzverordnung

mit viel Aufwand bedacht und

nachgewiesen worden. Es steht auch

zu befürchten, dass Zusatzmaßnahmen

zu einem Standard werden,

hinter dem andere Akteure nicht

zurückstehen können, obwohl sie es

nach geltendem Recht dürften.

Hinzu kommt: der erhoffte Vorteil,

für den dies alles in Kauf genommen

wird, tritt möglicherweise gar nicht

ein; der Wunsch, durch die zusätzlichen

Maßnahmen Vertrauen und

Akzeptanz zu stärken, scheint sich in

der Praxis nicht unbedingt zu erfüllen.

Die fehlende Überzeugungskraft

erscheint dabei durchaus nachvollziehbar:

je mehr Sicherheitsvorkehrungen

und Kontrollen man zusätzlich

freiwillig „anbietet“, desto

mehr gewinnt der Unbeteiligte den

Eindruck, die betreffenden Stoffe

müssten doch sehr gefährlich sein.

Ein anschauliches Beispiel für die

Schwierigkeiten der Überzeugungsbildung

bieten auch die Erfahrungen

aus Sachsen. Nachdem das sächsische

Umweltministerium die erste Anlieferung

von Bauschutt aus dem KKW

Stade zu einer sächsischen Deponie

mit einer öffentlichen Kontrollmessung,

zu der alle Bürger und die Presse

eingeladen waren, begleitet hatte und

die Messung eine Aktivität weit unterhalb

der Freigabewerte bestätigte,

wurde von der Bürgerinitiative unterstellt,

man habe für diese Lkw-Ladung

ENERGY POLICY, ECONOMY AND LAW 215

41 https://www.umwelt.niedersachsen.de/startseite/aktuelles/pressemitteilungen/antwort-auf-die-muendliche-anfrage-MA23-133701.html.

42 Röller (Fn. 16), S. 150 f.

43 Ebenda, S. 151 f.

44 Siehe Mitteilung des Niedersächsischen Umweltministeriums vom 17.07.2015: https://www.umwelt.niedersachsen.de/startseite/aktuelles/pressemitteilungen/

antwort-auf-die-muendliche-anfrage-wo-soll-der-freigemessene-bauschutt-aus-dem-kkw-stade-hin--135541.html.

45 So die Stellungnahme des Sächsischen Staatsministeriums für Umwelt und Landwirtschaft vom 15.05.2018, https://kleineanfragen.de/sachsen/6/13160-neuerbauschutt-aus-atomkraftwerken-akw-in-sachsen.

46 Abschlussbericht (oben Fn. 38), S. 10.

47 So auch der „Abschlussbericht“ aus Schleswig-Holstein (oben Fn. 38, S. 14 unter dem Stichwort „Zuweisung (‚Rückfallvariante‘)“.

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

atw Vol. 65 (2020) | Issue 4 ı April

ENERGY POLICY, ECONOMY AND LAW 216

gezielt besonders gering belasteten

Bauschutt zusammengesucht. 48

Als

das Ministerium daraufhin in der

Folgezeit mehrere unangekündigte

Messungen von Lkw-Ladungen vornahm,

die ebenfalls Werte weit unterhalb

der Freigabewerte ergaben, 49

wurde das offenbar nicht mehr zur

Kenntnis genommen. 50

Da die Deponierung somit grundsätzlich

streitbehaftet zu bleiben

scheint, stellt sich die Frage, ob der

Bergversatz von Bauschutt aus Kernkraftwerken

eine Lösung wäre, die

Aussichten hat, vor Ort akzeptiert zu

werden. Praktische Erfahrungen bestehen,

soweit ersichtlich, noch nicht,

so dass man letztlich Mutmaßungen

anstellen muss. Für eine Akzeptanz

spricht, dass die Abfälle auf diesem

Wege definitiv und für jedermann

leicht nachvollziehbar aus der Biosphäre

ausgeschlossen werden; das

subjektive Sicherheitsgefühl könnte

durch die Verbringung tief unter Tage

gestärkt werden. Andererseits könnte

der Bergversatz aber auch sachlich

nicht gerechtfertigte Assoziationen an

ein Endlager für radioaktive Abfälle

hervorrufen und – wie oben schon für

freiwillige Zusatzmaßnahmen ausgeführt

– die (unzutreffende) Vorstellung

von einer Gefährlichkeit der

so entsorgten Abfälle nähren. Zudem

dürfte dieser Entsorgungsweg oft

mit der Verbringung in ein anderes

Bundesland verbunden sein, womit

wiederum die dazugehörige Grundsatzdiskussion

aufgerufen würde.

Insofern käme es hier wohl entscheidend

auf eine klare und zielführende

Kommunikation an. Das gilt

im Übrigen für alle einschlägigen

Entsorgungswege.

Letztlich wird es aber unausweichlich

sein, dass zumindest für einen Teil

der Rückbaumassen die bestehenden

rechtlichen Rahmenbedingungen für

die Entsorgung, die oben ausführlich

dargestellt wurden, von den politischen

Verantwortungsträgern mit

klaren, möglichst zwischen den

Bundesländern abgestimmten und

gut und verständlich kommunizierten

48 Röller (oben Fn. 16), S. 151 f.

49 Ebenda.

50 Auch Feldmann (oben Fn. 17) stellt anhand dieses Fallbeispiels fest, dass das Bemühen um Transparenz ins Leere gegangen sei.

Entscheidungen umgesetzt werden.

Anders kann der gesetzlich vorgeschriebene

unverzügliche Abbau

der Kernkraftwerke kaum vonstatten

gehen.

Author

Rechtsanwalt Dr. Christian Raetzke

Beethovenstr. 19

04107 Leipzig

Imprint

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ISSN 1431-5254

Energy Policy, Economy and Law

Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

atw Vol. 65 (2020) | Issue 4 ı April

Excursus to the World of Nuclear Medicine

Andreas Schmidt, Klaus Tatsch, Beate Pfeiffer, Verena Störzbach and Maximilian Kauth

217

1 Introduction Nuclear medicine is based on the application of a variety of radiopharmaceuticals, either in

the form of pure unsealed radionuclides or as radiolabeled compounds (tracers) for diagnostic and therapeutic purposes

(endoradiotherapy).

ENVIRONMENT AND SAFETY

| Fig. 1.

Example of a functional test of human kidneys. Data derived from the acquired image sequence (upper part) allow to inform about the partial function of the kidneys (red left kidney, green

right kidney), quantitative parameters as tubular extraction rate, and excretion of the radiopharmaceutical from the kidney into the bladder.

The production of artificial radionuclides

with suitable physical properties

for imaging in combination

with tracers has enabled imaging a

broad variety of functional (biochemical

and physiological) processes in the

human body and in animals. These

techniques are complementing classical

anatomical imaging such as radiological

methods.

The latest generation of noninvasive

hybrid imaging systems such

as PET/CT or SPECT/CT combine

emission computed tomography with

transmission computed tomography

(CT) to almost simultaneously collect

functional and anatomic information.

The information is merged into so

called fused (coregistered) images

thus allowing to establish diagnoses

on 3D data sets and, if desired, additionally

over time (dynamic).

While endoradiotherapy is based

on the emission of ionizing radiation

of either alpha or beta particles from

inside the body, radiotherapy (external

beam radiation therapy) is a therapeutic

discipline that uses gamma

radiation, X-rays, electron beams,

neutrons, protons, and heavy ions

from outside the body or, when using

encapsulated sources, from inside the

body.

Radioimmunotherapy and radiochemo

therapy complement the discipline

of radiotherapy. All disciplines

making use of ionizing radiation are

regulated by the Radiation Protection

Ordinance (StrlSchV) within the

framework of German nuclear and

radiation protection law.

2 Medical imaging

methods at a glance

The various medical imaging techniques

can be categorized either by

the applied technique, for example:

p X-rays stored on film or digital

media, computed tomography

(CT) or transmission CT

p Scintigraphy, planar or in form of

emission computed tomography

(ECT) e.g. as utilized in singlephoton

emission computed tomography

(SPECT) or positron emission

tomography (PET)

p Sonography, medical ultrasound

p Magnetic resonance imaging

(MRI)

p Endoscopy (video endoscopy)

Or by the type of images resulting

from the applied techniques:

p one-dimensional (1D),

two-dimensional (2D) or

three-dimensional (3D)

p projection data

p cross-sectional images

(axial, coronal and sagittal)

p functional images (Figure 1)

p fused images e.g. such as

coregistered images of MRI and

PET (Figure 2)

p static, whole-body or dynamic

images.

2.1 Radiography

The projection of a volume (3D) on a

planar image (2D) is the most common

method, where the patient is

being irradiated by X-rays from

exterior.

The X-rays are absorbed by the anatomical

structures they pass through

in differing amounts depending on

the density and composition of the

material. X-rays that are not or only

partially absorbed pass through the

object and are recorded on X-ray

sensitive film or digital media.

Objects being irradiated within the

same beam direction are overlaying

each other in the resulting image. It is

difficult to distinguish if the contrast

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atw Vol. 65 (2020) | Issue 4 ı April

ENVIRONMENT AND SAFETY 218

| Fig. 2.

FDG PET (upper part) and coregistered MRI and PET (lower part) images

using different color scales. The FDG PET allows the imaging of the

physiological and pathological glucose meta bolism. Regions with a

higher FDG uptake are indicating an enhanced glucose metabolism.

The coregistration with the MRT and its morphological information allows

to exactly localize the meta bolically active areas.

seen results from the material density

and subsequently higher absorption

or simply the layer thicknesses.

2.2 Computer Tomography

Computer tomography is the creation

of a 1D absorption profile of an object

from multiple directions. Several of

these absorption profiles are being

used to generate a 3D structure.

The computer-based image reconstruction

system is capable to determine

the particular absorption for

each volume element of the object

(so-called voxel which corresponds to

a 3D pixel) and subsequently calculate

the image. For many years the filtered

back projection algorithm was state of

the art for the image reconstruction

whereas in the recent years more and

more CT systems use iterative reconstruction.

[1] [2]

The calculated image is a transverse

section through the object. With

several rotations around the object

adjacent sectional images can be

created and accumulated to volume

graphics that consist of several dozen

or up to several hundred individual

sectional images.

suitable imaging devices such as

gamma cameras.

Radioactively labeled compounds

(so-called tracers) are injected into

the human or animal body prior to

scintigraphy.

These tracers are transported,

metabolized, or may be accumulated

in the target organ or tissue de pending

on their respective metabolic characteristics.

Resulting images provide mainly

physiological, pathophysiological and

functional information about the

scanned organism. Thus, information

is provided about the spatial distribution

of the activity (localization of

pathological processes) and changes

of activity distribution over time

(functional diagnosis).

2.4 Emission computer

tomography (ECT)

Where the CT (section 2.2) is based on

rotation of the x-ray source and detector

assembly around the object (transmission),

ECT detects the radiation

emitted from inside the body, i.e. the

body is the source.

Both imaging methods often use

iterative reconstruction for image

generation (most commonly).

ECT has an obvious relevance in

the field of nuclear medicine since it

allows the creation of transsectional

images in three orthogonal planes

(transverse, coronal, sagittal) of the

tracer distribution within the human

body, subsequently allowing to draw

conclusions about functionalities in

organs, tissues, or cell structures.

2.4.1 Single-photon emission

computed tomography

(SPECT)

Principally this technique is based

on scintigraphy (section 2.3) and is

used to detect gamma radiation

emitted by either radionuclides and/

or tracers that have been injected

intravenously.

Most often a dual-head gamma

camera rotates around the body

and detects the radiation from

different angles, thus collecting

projection data from a 360° rotation.

The planar projection data are

then reconstructed and converted

into 2D and 3D images. Special

refinements of this technique are

available e.g. in form of gated

SPECT acquisition where a cardiac

cycle may be divided into time

bins, triggered by an ECG (electrocardiogram).

This technique may

allow not only to assess regional

myocardial perfusion but also functional

para meters as regional wall

motion ab normalities or calculation

of the ejection fraction of the left

ventricle of the heart, Figure 3.

2.4.2 Positron emission

tomography (PET)

In contrast to SPECT, PET scanners

require radionuclides that emit

positrons (b + emitters) only. PET

detects the annihilation radiation

resulting from the interaction

of a positron with an electron

inside the body. The resulting

two photons are emitted at an

approximate angle of 180 degrees

2.3 Scintigraphy

Imaging regional activity distribution

in a scintigram is a functional- oriented

examination used in nuclear medicine.

The scintigram is based on the

external detection of radiation from

radionuclides inside the body by

| Fig. 3.

Gated SPECT for imaging myocardial perfusion abnormalities. On the left hand side the diastolic and

systolic tracer distributions are shown. On the right hand side blood perfusion conditions can be

quantitatively assigned to the different regions. Gated imaging allows to determine several additional

cardiac output parameters.

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atw Vol. 65 (2020) | Issue 4 ı April

to each other and with an energy

of 511 keV (rest energy of an electron).

These two photons from one

annihilation process lead to coincidences

in opposing detectors. The

spatial and time-related distribution

of the detected decays allows to

determine the spatial distribution of

the tracer.

The PET scanner contains of

many photon detectors arranged

in a ring around the gantry. The

detector rings have 30-40 detector

modules, each detector module

consisting of 4-8 detector blocks

that are equipped with several

single crystals. This results in

approximately 10,000 detector crystals

which are arranged in a ring

( scintillation counter) and coupled to

approximately 1,000 photomultipliers

enabling the detection of the annihilation

radiation. Coincidences

between two of these detectors are

registered without physical collimation

(in contrast to SPECT). This

advantage results in higher count

rates, efficiency, reso lution and

ultimately image quality. Today

instead of photo multipliers also

technology based on semicon ductors

is used.

| Fig. 4.

Example for the use of F-18-FDG in PET/CT in oncology. In the upper part the PET images show the distribution of the glucose

metabolism. The lower part of the picture shows the PET images coregistered with diagnostic CT to allow morphologic evaluation and

anatomic allocation of the functional images. The patient suffers from lesions with intensively storing thoracic and abdominal foci.

ENVIRONMENT AND SAFETY 219

3 Nuclear Medicine

Nuclear medicine is based on the use

of open radionuclides or radiopharmaceuticals

(tracers) with rather

short physical half-lives that emit α,

b - , b + or γ radiation.

Prior to injection they are usually

coupled to substances suitable to

depict organ specific processes such as

perfusion, metabolism, organ functions,

receptor availability and many

more.

A wide range of “in-vivo” measurement

methods can be used to

assess the function of organs and/or

organ systems, and to track the

effects of treatment (e.g. chemotherapy

or radiotherapy) and a range

of physiological processes within the

body.

Functional imaging in nuclear

medicine is an interdisciplinary field

which supports almost all medical

disciplines. In particular, but not

exclusively, these are:

p Oncology

p Urology

p Gynecology

p Otorhinolaryngology

p Cardiology

p Dermatology

p Surgery

p Endocrinology

p Neurology

| Fig. 5.

Use of F-18-FDG in PET/CT (neurology).

3.1 Diagnostics

3.1.1 Radiopharmaceuticals

in daily routine used

for PET/CT

F-18-FDG (fluorodeoxyglucose)

This is the most commonly used

tracer for PET. Tumor cells often

have an increased affinity for

glucose. Like the unlabeled physiological

glucose FDG is taken up

intracellularly by the glucose transporter

and phos phorylated by the

glucose-6-phosphatase enzym, however,

then the further metabolic

pathway is blocked for FDG. Therefore

FDG is for some time trapped

in the cell and the retention rate

in the tissue is mainly related to the

number and activity of the glucose

transport. Similar mechanisms apply

to various inflammatory cells. However,

keep in mind that not all types

of tumors and not all types of

inflammation are FDG positive. F-18

labeled fluorodeoxy glucose (b + )

is a positron emitter, the coincident

gamma radiation of the corres ponding

annihilation process can be detected

by the PET scanner. State-of-the-art

PET scanners are always combined

with a CT unit. PET and CT are

consecutively acquired without the

patient moving between the two

examinations. This achieves the

greatest possible spatial corre lation

between functional and structural

imaging.

For most oncological indications,

a hybrid scanner (PET/CT) is used

for whole-body acquisitions in 3D

mode. The quantitative SUV ( standard

uptake value) determination can

objec tify the degree of metabolic

activity.

In the case of neurological disorders,

such as some neurodegenerative

diseases, the FDG brain metabolism

can also be examined.

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ENVIRONMENT AND SAFETY 220

| Fig. 6.

Progress monitoring of NET with Ga-68-DOTA-TATE in PET/CT. The PET images (upper part) show the Ga-68-DOTA-TATE distribution in

a patient with extensive hepatic metastatic NETs. The coregistered PET/CT cross sections (lower part) allow a morphologic evaluation

and anatomic allocation. The progress of the metastatic spread, i.e. quantity and size, can be assessed from those images.

| Fig. 7.

Example for the use of Ga-68-PSMA in PET/CT (metastases of a prostate cancer). The upper part and the picture on the right hand

side show the PET images that clearly indicate large metastases of a prostate cancer. In the lower part the coregistration with CT

gives more information about the exact location.

Ga-68-HA-DOTA-TATE

for NET tumors

HA-DOTA-TATE refers to a protein

molecule which resembles the body’s

own hormone somatostatin.

Its special feature is that this molecule

(analog to the physiological

somatostatin) binds to somatostatin

receptors (proteins or protein complexes)

which are highly expressed

on certain types of neuroendocrine

tumors (NET) (e.g. gastrointestinal,

pancreatic). If this molecule is labeled

beforehand with a radionuclide, it is

possible to visualize the tumor manifestations

in the body by means of

PET.

HA-DOTA-TATE is labeled with

gallium-68, a positron emitter (b + ),

which is used for diagnosis, staging

and restaging of many NETs. In specific

types of tumors most interestingly

the so called theranostic concept

may come into play. If the tumor

burden is high and a high amount

of receptor availability is documented

by a preceding diagnostic Ga-68

HA-DOTA-TATE scan then replacing

Ga-68 by Lu-177 may offer a specific

therapeutic option to effectively

treat those patients using the same

principle (radiopeptide therapy).

Lutetium-177, a beta emitter (b - ) with

a gamma radiation component, is

labeled to the same protein molecules.

The therapeutic effect is based on the

b - radiation component in the target

areas (tumor manifestations). The

additional gamma radiation component

may be used for dosimetry

and SPECT imaging following the

treatment.

Ga-68-PSMA-ligand

for prostate cancer

PSMA (prostate-specific membrane

antigen) is a protein physiologically

found on prostate cells, however

which is specifically highly expressed

on prostate cancer cells. Thus labeled

with Ga-68, PSMA is a most interesting

target suitable for PET/CT

imaging in prostate cancer to determine

very early recurrent tumor and

metastasis. In dependency of the

imaging results the further therapeutic

strategy for the patients may be

modified in many cases (Figure 7).

| Fig. 8.

Bone scans of two different patients. Left: Female patient with normal homogenous distribution

of the tracer over the whole skeletal system. Right: Male patient with multiple osseous metastases

in the upper and middle axial skeleton and pelvis of a prostate carcinoma.

3.1.2 Radiopharmaceuticals in

daily routine for SPECT/CT

Tc-99m-diphosphonate

for skeletal diagnosis

Bone scintigraphy provides information

on bone metabolism. Since

metabolic changes usually precede

Environment and Safety

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atw Vol. 65 (2020) | Issue 4 ı April

| Fig. 9.

Pulmonary perfusion (SPECT/CT).

| Fig. 10.

Normal pulmonary ventilation (above) and perfusion (below) (scintigram).

morphological findings, bone scintigraphy

(Figure 8) is a very sensitive

diagnostic procedure and can often

detect pathological findings earlier

than other examinations (e.g. conventional

x-rays). In addition, bone scintigraphy

as a whole-body examination

allows assessment of the whole skeleton.

The radiopharmaceuticals used are

Tc-99m phosphonates which are

attached to the bone, depending on

the extent of bone metabolism.

Skeletal metastases frequently cause

increased bone metabolism because

of their stimulation of osteoblastic

activity. Increased bone metabolism is

also found in fractures, traumas, and

some metabolic bone disorders.

Tc-99m-Mag3

for renal function testing

Mag3 is a small peptide (mercap toacetyltriglycine

= “glycyl- glycylglycine”).

It is extracted from the

blood by the tubular cells of the kidney,

secreted tubularly and almost not

reabsorbed. Renal scintigraphy with

Mag3 is used to detect two important

parameters: a) clearance and b) partial

function of both kidneys.

In this context, clearance reflects

the tubular extraction rate (TER)

which is calculated from the activity

administered and from the activity

rates measured in the serum at

defined time points.

With renal function scintigraphy

it is possible to determine global

clearance values, partial function of

the respective kidneys, identify

defects in the parenchyma of the

kidneys, assess the outflow and detect

any extravasation from the urinary

tract.

Tc-99m-MIBI

Myocardial perfusion scintigraphy

(MPS) is a non-invasive examination

procedure which illustrates the relative

distribution of blood flow within

the myocardium (left ventricle) in a

3D image (Figure 11). See also

chapter 2.4.1.

As a functional imaging technique,

it differs fundamentally from morphologically

based imaging such as

coronary angiography or coronary

CT angiography (CTA) and magnetic

resonance angiography (MRA) which

ENVIRONMENT AND SAFETY 221

Tc-99m-HSA combined with

Tc-99m-“gas” for lung diagnosis

Lung diagnosis in nuclear medicine is

usually performed as a combined V/P

(ventilation/perfusion) examination

using the SPECT/CT technique

(Figure 9). For assessment of lung

per fusion, a temporary microembolization

of capillaries takes place after

intravenous injection of small protein

particles (microspheres, approx. diameter

10 to 30 μm), the size of which

is slightly above the mean capillary

diameter. Distribution of the radiopharmaceutical

corresponds then to

the regional distribution of pulmonary

perfusion.

For assessment of lung ventilation,

a “dry” aerosol of ultra-fine particles

(size

atw Vol. 65 (2020) | Issue 4 ı April

ENVIRONMENT AND SAFETY 222

image the coronary arteries directly

but may not allow to draw conclusion

to which extend eventual coronary

artery stenosis affect local myo -

cardial perfusion. The main clinical

application for MPS is assessment of

coronary heart disease. MPS is performed

after intravenous injection of

a radio pharmaceutical which is taken

up by the cardiomyocytes in a

perfusion- dependent manner. To

assess the hemodynamic effects of

changes in the coronary vessels on regional

myocardial perfusion, SPECT

images of the myocardium after

injection of a radiopharmaceutical

are taken after physical or druginduced

stress and at rest, and the

resulting patterns of findings are

interpreted.

Sentinel lymph node (SLN)

Sentinel lymph node diagnostics is

another example applying nuclear

medicine diagnostics.

It is used in the early stages of

several types of tumors (e.g. breast

cancer, malignant melanoma, head

and neck tumors) which may spread

via lymph vessels to regional and/or

more distant lymph nodes.

For this procedure radioactively

labeled protein particles are injected

under the skin close to the primary

tumor site. It is expected that lymph

drainage via lymphatic channels will

lead to consecutive storage of the

radiopharmaceutical in the next

regional lymph node. This initial first

filter station is called sentinel lymph

node (SLN) and has an important

predictive role. The Tc-99m nanocolloid

used for this type of scintigraphy

is a human albumin-derivative

with a half-life of 6.01 hours and an

energy of 140 keV, since colloids are

trapped in lymph nodes this principal

is an ideal tool to detect the SLN.

Imaging is mostly performed

approximately 24 hours before the

planned surgical removal of the

detected SLN lymph node (at that

time point radiation burden for

the surgical staff is below relevant

borders). For imaging SPECT or

SPECT/CT are the favourable techniques

(Figure 12) which facilitate to

localize the SLN with high diagnostic

accuracy.

The approximate location of the

lymph node is also marked on the

skin. On the day of surgery, a handheld

gamma probe (semi-conductor

or scintillation detector) is used to

detect the labeled lymph node intraoperatively

and then it is removed

surgically.

The probe’s spatial resolution is a

decisive criterion for the success of

detection, i.e. the full width at half

maximum (FWHM) of the resolution

curve should not be greater than the

actual target volume.

The real advantage of the sentinel

lymph node (SLN) labeling concept is

a selective surgical removal of the SLN

instead of removing many lymph

nodes from the axillar region with

might result in lymphedema of the

respective arm later.

The efficiency of the limited surgical

intervention results in a reduced

operating time, reduced extent of the

surgery and finally the histological

examination of the specific SLN probe

after its removal which – as already

mentioned – is a valuable predictive

marker for correct assessment of the

tumor stage.

3.2 Therapy

Nuclear medicine therapy today is

mainly focused on thyroid disorders,

neuroendocrine tumors, liver tumors

and prostate tumors. This involves the

use of open radioactive substances

which are administered either orally

or intravenously, which participate in

specific metabolic pathways and on

this way reach the target tissue in

the patient’s body. Radioactive

iodine-131 is used for thyroid treatment,

radio active Lutetium-177 for

radioligand therapy (neuroendocrine

tumors and prostate cancer) and

radio active Yttrium-90 for selective

internal radiotherapy (liver tumors).

Only iodine-131 is administered in

pure form. As described earlier the

other mentioned radionuclides are

labeled with pharmaceuticals for their

therapeutic use. Depending on the respective

equipment, the labeling procedure

may take place in the hospital’s

| Fig. 13.

The whole-body scintigrams show the time course of the activity distribution typically for a time of 3 days (post-injection (pictures 1 & 2), 24 h (3 & 4), 72 h (5 & 6)). For each scan the ventral

(left) and dorsal (right) images are shown. From the ROIs of different organs and the standard syringe (bottom) the activity curve and subsequently the dose can be determined for each organ.

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own nuclear medicine hot laboratory

or the tracers are delivered ready to

use. These radiotracers are mostly

b-radiating nuclides which transfer

their radiation energy to the tissue

during radioactive decay. The aim is to

destroy the diseased tissue with its

radiation. Generally before a planned

treatment tests are carried out to

establish parameters for the dosimetric

concept (intensity of accumulation

in the target structure,

biological half-life, etc.) Following

therapy specific nuclear medicine

imaging devices (SPECT/CT, PET/CT,

gamma cameras) are used to document

the distribution of activity in the

patient’s body after therapy.

For radiation protection reasons

and for observation, patients must be

admitted to a nuclear medicine ward

for therapy. During their stay in

the hospital, regularly radioactivity

measurements are performed as well

as imaging of parts of the body or

whole-body scans.

3.2.1 Dosimetry for treatment

with open radioactive

substances

These scintigrams are used for posttherapeutic

dosimetry. The aim of

dosimetry is to determine the radiation

dose in the patient’s body. The

dose is the amount of radiation energy

transferred to the tissue and is

described by the formula “dose =

energy/mass” (using the unit Joule/

kg = gray). The dose is primarily

determined in the tumor tissue or for

example in the diseased thyroid.

Radioligand therapy also calculates

the dose of individual organs, such as

the kidneys, spleen, liver, salivary

glands and bone marrow. For the

dosimetry of these organs, it is necessary

to determine the activity curve in

them, since the transmitted radiation

energy is proportional to the number

of radioactive decays that have taken

place in the organ. For this purpose,

various images are taken during

radioligand therapy using a SPECT/

CT camera from GE. They include

several planar scintigrams of the

whole body from the ventral and

dorsal aspect and a tomographic

image (SPECT/CT), usually of the

patient’s trunk. The evaluation software

makes it possible to evaluate the

planar images in such a way that the

radiation pulses arriving in the camera

can be determined quantitatively. The

imaged organs or metastases relevant

for dosimetry can be marked as

regions of interest (ROI) and the

pulses displayed. A calibration factor

| Fig. 14.

Thyroid scintigraphy with Tc-99m-PTT - Left: Image with pinhole. A focal autonomy can be observed in the left thyroid lobe.

Eventually there is also a focal autonomy of the right thyroid lobe. Right: Focal autonomy in the left thyroid lobe with almost

completely suppressed paranodular tissue.

is required to calculate the activity in

the organ/tumor from the pulses. The

activity in the patient is known from

the first whole-body scan (measuring

the excretion makes it possible to

deduce the activity remaining in the

body), thus it is possible to calculate a

calibration factor from the total

number of incoming pulses in the

camera. In addition, a 50 ml syringe

filled with known activity is included

in each whole-body image. A calibration

factor can also be determined

here by creating an ROI. The activity

of the organs or tumor/metastases

during SPECT/CT imaging can be

determined with the aid of the evaluation

software, as the equipment has

been calibrated in advance.

A mathematical function, which

approximately describes the activity

curve (usually an exponential function),

is then created for the activity

curve, determined using the scintigrams,

in the relevant organs or in the

tumor tissue. The time integral of this

function represents the sum of all

decays that have taken place in the

organ or tumor, which is important for

dose calculation. To calculate the dose

also requires factors which describe

how much energy is transferred to the

tissue per decay; the mass of the

organ/tumor is also relevant. These

two pieces of information can be

found in the so-called S values

according to RADAR (Radiation Dose

Assessment Resource, related literature

at ICRP and MIRD).

This information is used as the

basis for dosimetry which provides an

important indication as to whether

target doses have been reached in

tumors, metastases or in benign

thyroid tissue, or which radiation dose

healthy organs have been exposed to

by the therapy.

3.2.2 Radioiodine therapy

of the thyroid

Probably the most classic and established

therapy method in nuclear

medicine, it has been practiced for

more than 50 years and is administered

in Germany 50,000 times a year.

Indications are malignant disorders

(thyroid cancers or their iodinestoring

metastases), as well as benign

disease such as autonomies, other

forms of hyperthyroidism or autoimmune

diseases such as Graves’

disease.

Scintigraphy using Tc-99m-PTT

(pertechnetate) is used to confirm

suspected diagnosis suitable for radioiodine

therapy. Pertechnetate ions are

actively taken up in thyroid cells in a

similar way as iodide ions via the

sodium iodide symporter. As a result,

the pertechnetate uptake correlates

to the organ’s iodine avidity. The

regional uptake behavior and the

extent of uptake is assessed quantitatively

in the scintigram. The aims

of the examination are therefore a

planar functional image of the thyroid,

which is always correlated with a

sonogram for anatomical orientation,

and the quantitative determination of

pertechnetate uptake (TcTU).

This examination is followed by a

radioiodine test, i.e. the imaging of a

compara tively small amount of activity

of iodine- 131 (approx. 5 MBq). This

uptake measurement (quantification

of the max. iodine uptake capacity of

the thyroid), which typically takes

place after 5-8 days, is used to

calculate the amount of I-131 to be

administered during therapy in the

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ENVIRONMENT AND SAFETY 224

| Fig. 15.

Thyroid scintigraphy with I-131 for radioiodine test. A homogenous

distribution throughout the thyroid can be observed for this patient with

hyperthyroidism.

1) Other controlled

areas are the “hot

laboratory”, the

decay facility for

radioactive sewage

of the associated

nuclear medicine

treatment center, as

well as the solids

store which serves

as an interim

storage facility for

radioactive waste

before it is routed to

the regular disposal

path. Bed linen, for

example, is also

stored here.

target volume. The radioiodine test is

usually performed on an out-patient

basis (Figure 15).

The actual radioiodine therapy

takes place in one of the hospital’s

controlled 1 areas. Among other

things, this is characterized by staff

access restrictions. After leaving these

areas, a hand-foot-clothing monitor is

used to measure any contamination.

Patients are admitted to hospital

for at least 48 hours.

Accordingly, the therapeutic effect

is based on administration of the

I-131 nuclide, a b-emitter with

0.6 MeV, which is almost exclusively

taken up in thyroid cells. Depending

on the therapy, the activity administered

is between 150-1200 MBq

for benign disorders. Depending on

the thyroid’s metabolism, patients

may be ad ministered additionally

suppressive thyroid hormones, e.g.

to suppress the uptake of I-131 in

healthy thyroid tissue and to restrict

the uptake only to auto nomous

tissue as target tissue.

In the case of malignant disorders

of the thyroid, the activity administered

may be many times higher in

order to achieve the therapeutic goals.

4 Conclusion

Unlike any other medical discipline,

nuclear medicine provides insights

into many metabolic pathways illustrating

various pathophysiologic concepts

of the human body. It also combines

a large number of medical disciplines

with physics, special machine

construction and computer engineering.

There are many research reports in

the field of artificial intelligence

where machine learning and texture

analysis in fusion imaging may lead to

more advanced imaging technology

which, coupled with even more specific

tracers, will enable even more targeted

and individualized therapy in

the future.

Acknowledgement

Many thanks to our colleagues and

co-authors at the Städtisches Klinikum

Karlsruhe without whose expertise,

but above all without whose time,

help and support, this article would

not have been possible.

References

[1] W. A. Calendar: Computed Tomography. Basics, device

technology, image quality, applications with multilayer spiral

CT. Publicis MCD advertising agency, Munich 2000, ISBN

3-89578-082-0.

[2] T. M. Buzug: Introduction to computer tomography:

Mathematical-physical basics of image reconstruction.

Springer, Berlin/Heidelberg/New York 2002,

ISBN 3-540-20808-9 limited preview in Google book search

Further sources

| Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit

(BMU) [Federal Ministry for the Environment, Nature

Conservation and Nuclear Safety]

| Strahlenschutzkommission (SSK) [The German Commission

on Radiological Protection]

| DGMP – Deutsche Gesellschaft für Medizinische Physik e.V.

[German Society for Medical Physics]

| Guideline to the Radiation Protection Ordinance – Radiological

protection in medicine

Authors

Dipl.-Ing. Andreas Schmidt

Radiation and environmental

protection engineer

Prof. Dr. med. Klaus Tatsch

Director of the Department

of Nuclear Medicine

Beate Pfeiffer

Senior medical-technical

radiology assistant

Dipl.-Ing. Verena Störzbach (BA)

Radiation protection officer/

Medical physics expert

Dr. rer. nat. Maximilian Kauth

Senior physicist

Städtisches Klinikum

Karlsruhe gGmbH

Department of Nuclear Medicine

Moltkestr. 90

76133 Karlsruhe

Germany

| Fig. 16.

Whole body (left) and SPECT/CT (right) images of a patient with thyroid cancer for metastases screening. The I-131 distribution

during the therapy shows no pathological accumulation. The accumulation in bladder and stomach is due to the excretion

of the radionuclide.

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Radiation in Art and Cultural Heritage

Frank Meissner and Andrea Denker

225

1 Introduction Art objects like paintings or sculptures represent a considerable part of our history. Besides the

works of art that survived, further remnants are considered of major importance to understand the development of

mankind, like archaeological artefacts. All these objects – art and cultural heritage – give insight into the past and are

essential archives to understand our history. The objects themselves are conserved and studied by specialists, based on

classical knowledge and experience of art historians or archaeologists, but more and more supported by natural sciences

and technical investigation methods. The application of ionising radiation in art history, archaeology or palaeontology

is less known, but represents an important branch of the methods when it comes to the analysis of material composition

or imaging techniques of historically valuable objects. Nuclear methods and X-ray technologies are the most important

applications because of their quasi non-destructive features and their macroscopic to microscopic range of the

interactions with the object. Depending on the questions to be answered, one can imagine to introduce various

radiations from nuclear reactors, accelerators, spallation sources or X-ray generators. In this paper, a few selected

examples are presented to give brief insight into the use of reactor neutrons and X-rays in art and cultural heritage and

the results that can be obtained.

2 Methods and results

Nuclear methods and X-ray applications

have found entrance into the

investigation of art and cultural

heritage objects. Worldwide, several

institutes have launched research projects

or even founded working groups

in order to use reactor neutrons,

accelerator particle beams or X-rays in

the research of paintings or historical

artefacts. Many of these projects are

spin-offs from material testing and

material studies in solid state physics.

Results are presented at conferences

dedicated to the specific research

like the international “Synchrotron

Radiation and Neutrons in Art and

Archeology” Conference [1], connecting

nuclear physicists with e.g.

art historians, conservators, archaeologists

and paleontologists. Many of

the non-destructive testing methods

in material sciences are applicable to

art and cultural heritage, however,

two important constraints have to be

kept in mind.

First, it is evident that the use of

particles from accelerators or reactors

must be restricted to pure research or

very limited numbers of specific projects

since the technical effort for the

production of the radiation and the

facilities needed for their application

is very high. Besides nuclear reactors,

this is also valid for synchrotron facilities

which are well suited to produce

high quality X-rays for such investigations

and usually operate dedicated

beamlines.

Second, important samples in art

and cultural heritage are unique and

irreplaceable. Owners and conservators

might therefore be reluctant to

offer them to research institutes for

such studies, unless there is close

cooperation and trust. Even if an

object leaves a museum or conservatory

site, considerable efforts and

costs for appropriate transportation

and insurance have to be taken into

account and the correct handling of

the objects within the conservatory

parameters always requires specialist

knowledge.

These constraints are usually not

limiting in the case of X-ray investigations

which take place on-site using

designated equipment like X-ray

generator tubes operated by museums

or mobile X-ray devices from external

service providers. Such X-ray studies,

in particular with the up-to-date hardware

and software, cover a large

fraction of the issues questioned by

the experts and are therefore the

first choice when it comes to imaging

or elemental analysis with X-ray

fluorescence.

Imaging methods with neutrons

are usually complementary to X-ray

imaging techniques, so each method

adds specific results because of the

different interaction mechanisms of

neutrons and X-rays in matter. Therefore,

the neutron results can be well

compared with those obtained by

X-rays [2,3,4,5,6].

Neutrons have no charge and

therefore exhibit a higher penetration

depth in matter as compared to other

particles and as compared to X-rays. In

particular, they can pass easily many

centimeters of dense materials like

iron, copper or lead, while their interaction

with light nuclei is larger and

thus scattering and attenuation is

higher in typical organic matrices of

elements like hydrogen, carbon, nitrogen

and oxygen. Besides, neutrons

may also interact with nuclei of the

elements in materials allowing activation

reactions. In this case, the specific

cross sections have to be taken into

account, which will depend on the

energy of the neutrons and the specific

nuclei they interact with. Reactor

neutrons offer the option to use fast

neutrons as well as thermal neutrons

with their different behaviour in

matter [3]. Neutrons have been used

in material sciences since many

decades and the use in art and cultural

heritage, as a later development, is

based on the experience therefrom.

Three methods are widely used, these

are:

p Neutron radiography/tomography,

which produces a twodimensional

or even threedimensional

image by detecting

the images revealed by absorbed

and scattered neutrons,

p Neutron activation analysis (NAA),

which is a method very sensitive to

the elemental composition of the

sample, and

p Neutron activation radiography

(NAR), which reveals images of the

distribution of activation products

by autoradiography.

For such studies, it is sometimes

possible to use accelerators for the

required neutron production, but

many specialists rely on nuclear

fission sources, which are represented

by reactors with dedicated beamlines

and defined neutron properties. In

Germany, the neutron source FRM-II

in Munich, the research reactor TRIGA

in Mainz and the (now shutdown)

research reactor BER-II in Berlin are

known for their neutron studies in art

and archaeology, some examples can

be found in [3,5,6,7].

For instance, the neutron activation

radiography (NAR) of a painting

is capable of analysing different paint

layers and the painting support. In

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RESEARCH AND INNOVATION 226

Isotope produced

by neutron activation

Pigment

other cases, the individual brushstroke

applied by the artist is made

visible, as well as changes and corrections

(so-called Pentimenti) introduced

during the painting process.

The NAR method is well suited for old

paintings – typically made before

1800 – when only a limited number of

known pigments was available. The

experimental principle is simple: In a

first step, the painting is exposed to a

flux of cold neutrons. Some of the

nuclei within the pigments capture

neutrons, which make the pigments

radioactive. Moving the support of the

painting within the neutron field

allows activation of the total area of

the painting. Due to the irradiation

time (which is usually a few hours),

only a few atoms are activated, for

which reason the method is considered

as being quasi non- destructive.

During the irradiation of the pigments,

a limited number of different

light and heavy isotopes is produced,

see Table 1.

After this activation, the neutroninduced

radioactivity decays with the

Half-life

56 Mn Umber, Dark Ochre 2.6 h

64 Cu Azurite, Malachite, Verdigris 13 h

76 As Realgar, Auripigment, Smalt 1.1 d

122 Sb Naples Yellow 2.7 d

124 Sb Naples Yellow 60 d

32 P Bone Black 14 d

203 Hg Cinnabar 47 d

60 Co Smalt 5.3 a

| Tab. 1.

Radioactive isotopes produced during the neutron irradiation of the pigments

used in a historical painting.

specific half-life of the respective isotope.

The β- and γ-radiation from the

induced activity blackens highly sensitive

films (X-ray films) or the radiation

is detected with imaging plates. The

resulting radiography unveils the

spatial distribution of the pigments

containing the radioactive isotopes.

The large advantage of neutron

activation radiography lies in the fact

that different activation products can

be detected on separate films, placed

subsequently on the painting over the

time. During the whole procedure, up

to four film layers or imaging plates

are used to register the radiation,

revealing the short-lived isotopes of

manganese and copper on the first

and second, and the isotopes of

mercury and phosphorus (due to

their longer half-lives) on the last film

layer. In addition, high resolution

Germanium-detectors analyse the

gamma spectrum from specific locations

on the painting, providing the

final information about the elemental

composition in the acti vated areas in

the paint layers.

One of the paintings which was earlier

studied by this method is a work of

Poussin. Nicolas Poussin (1594-1665)

is one of the main representatives of

pictorial classicism in the Baroque period.

Already in 1625, the legend of

the sorceress Armida and the crusader

Rinaldo had inspired Poussin to accomplish

the painting “Armida and

Rinaldo”, now owned by the Dulwich

Picture Gallery in London.

Another painting of Poussin’s circle,

which is conserved in the Gemäldegalerie

Berlin, “Armida abducts the

sleeping Rinaldo” (Figure 1), was

always supposed to be a copy after

Poussin. To clarify such questions of

attribution, investigations by means of

neutron activation radiography were

carried out at the BER-II reactor in

Berlin [7,8].

Surprisingly, the results showed

that besides the visible scene further

trees were arranged in the first

composition of the work (Figure 2),

but were later overpainted. This had

not been visible so clear in earlier

X-ray images of the painting. The

neutron activation results and further

investigations also revealed the same

pigments in these areas and their fit

into the overall composition. It was

therefrom strongly supported that the

first composition of the painting had

been changed by the artist. These

changes, called Pentimenti, are given

evidence that the painting can be

considered an original, because such

basic changes of the composition are

unlikely in a copyist’s work. All the

investigations performed on this

Berlin painting are now consistent

with a possible attribution of the

artwork to Nicolas Poussin himself.

| Fig. 1.

Nicolas Poussin: “Armida abducts the sleeping Rinaldo”, ca.1637

| Fig. 2.

First neutron activation radiography, assembled from 12 image plate records

of the painting from Fig.1. The coloured areas show those parts of the composition

which had been changed by the artist.

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| Fig. 3.

High-resolution digital radiography (section) of a French impressionist

painting by Frédéric Cordey,1854-1911, showing the structure of the

canvas, part of its fixing on the stretcher with nails on the right, various

damages in the form of losses, and the brush stroke structure which can be

considered characteristic for the painter.

Since Wilhelm Conrad Röntgen

discovered in 1895 that X-rays exhibit

a high penetration, even in materials

which are opaque for visible light, the

new radiation was an opportunity

for many applications, starting from

medicine, but soon in material

analysis, and also in the study of art

objects and archeological artefacts.

As a helpful tool for the questions

rised by art historians, archeologists

or conservators, the classical X-rays

were introduced systematically in

radiography studies of paintings by

the radiologist A. Faber in 1914 [9]

and it is well known that non-destructive

imaging with X-rays was a very

powerful tool to learn more about

mummies in the early 20 th century.

Already in 1924, the Pinakothek in

Munich and the Louvre in Paris

operated own X-ray devices for the

radiography of paintings [9]. In the

1930’s dedicated X-ray tubes for investigations

of painting were available

and although there was a period of

severe doubts and rumors about possible

radiation damages to valuable

art objects, radiography of paintings

with X-rays became more and more

accepted [9]. The thesis of C. Wolters

[10] on X-ray studies in art history is

one of the basic documents, which

comprised the knowledge so far and

worked out the important factors for

the interpretation of X-ray images of

paintings.

In the radiography of paintings,

the technique uses the contrast

achieved by different absorption of

X-rays in the pigments, very similar

to the contrast effect of different

tissues in medical X-ray imaging.

Heavy elements clearly dominate this

effect, like lead (in the form of the

pigment Lead-white) or – far less

important – mercury (red Cinnabar

pigment) or barium (Lithopone).

Before the mid of the 19 th Century,

Lead-white was used in every white

paint layer and blended with other

pigments to brighten these up. In the

case of paintings, high-resolution

X-ray images exhibit the distribution

of lead white pigment with excellent

accuracy and are well suited to analyse

the overall composition, the brushstrokes

of the painter (Figure 3) and

to discover changes (Pentimenti) and

overpaintings.

In an interesting project to be

mentioned here [11], of the French

Centre de Recherche et de Restauration

des Musées de France (C2RMF) in

cooperation with museums, several

important thought-to-be-lost paintings

of the French painter Frédéric Bazille

were rediscovered below the paint

layers of other paintings by Bazille –

which means that he was probably

very critical with his paintings and

overpainted several works. Similar

cases have been reported quite often.

X-ray radiography gives a pro jection

of the thin layers of a painting. Such

projections are similarly applicable to

other objects in cultural heritage like

sculptures or archeolo gical artefacts,

within the limits of the penetration of

denser materials. In the classic X-ray

tube, the radiation is emitted from a

small focal point in the tube, so

geometrical effects when analyzing the

projections have to be taken into

account. These are, how ever less

limiting for flat paintings in large focal

distances.

Later and up-to-now developments

comprise 3D X-ray tomography and

optimized X-rays sources, digital

recording instead of film material

and computed analysis. By these

| Fig. 4.

Measurement of X-ray fluorescence radiation (XRF)

with mobile equipment and professional data analysis

reveals the elemental composition of the pigments in the painting.

techniques, 3-dimensional X-ray imaging

with computed tomography became

standard, also in art and cultural

heritage studies. However, as in the

case of reactors and synchrotrons

already mentioned above, such

methods rely on stationary equipment

and are therefore not applicable when

an object shall not be moved from the

conservatory environment.

Moreover, X-rays are capable to produce

X-ray fluorescence in materials

that are irradiated, and this X-ray

fluorescence (XRF) is widely used for

the identification of characteristic

elements in pigments or for the analysis

of metallic alloys. The principle is

based on the fact that X-rays from

an X-ray source entering the surface

layers of the object (they will usually

not enter very deep) excite atoms in

the material which then emit their

characteristic K- or L-X-rays. These

characteristic X-rays are detected with

an energy dispersive detector. The

method is therefore capable to detect

the elemental composition of the

irradiated spot and thereby support an

assignment of these elements to the

pigments used. The X-ray source for

the excitation will be chosen adequately

and may be a synchrotron with

brilliant, monochromatic X-ray beam

in a research center or a small, dedicated

X-ray tube.

In their simple form with irradiation

spots adjustable between 1 and

8 mm, these instruments are small

and fully mobile, although they contain

the X-ray source and the detector.

They can therefore be brought directly

to the object and mounted on tripods

for accurate measurements, see the

typical setup in Figure 4.

Modern XRF instruments dedicated

to art and cultural heritage are

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RESEARCH AND INNOVATION 228

| Fig. 5.

A landscape painting with a large oak tree, assigned to a 19 th century artist.

available with additional options like

automated scanning of the surface of

the painting and automated recording

of the data from the investigated

object. Further optimizations are

precise, very small irradiation spots in

so- called Micro-XRF instruments

using collimating X-ray lenses. The

advantage is at hand: The area under

investigation is much better characterised

and the imaging resolution is

higher, while the scanning over the

whole surface reveals a complete

image of the elemental distribution.

These X-ray images seem much better

achievable than to expend high efforts

for neutron activation radiographies,

although it should be reminded that

low-Z elements are difficult or not at

all detectable in XRF because of the

attenuation of their characteristic

X-rays in the paint layers. Modern

scanning Micro-XRF instruments are

operated in investigations of important

art objects like in the actual

analysis prior to the restoration of

Rembrandt´s painting “Night Watch”

of the Rijksmuseum in Amsterdam

[12].

In the following example measured

at TÜV NORD – the case of a landscape

painting from the 19 th Century

– the power of X-ray radiography

combined with XRF analysis is

demonstrated (Figures 5 and 6). The

painting, showing several traces of old

damages, had been restored earlier

and by this occasion had been relined

(this means, a second canvas was

glued on the backside). The XRF

results from the elements in the paint

layers were consistent for the pigments

expected like iron (pigment

Siena or Umber) and manganese

( pigment Umber). The detection of

chromium (pigment Chrome Green

from the beginning of the 19 th century,

or the improved version of

hydrated chromium oxide, which

became known as Viridian Green

during the 1860’s) allows to date the

painting into the 19 th century. Before

the introduction of these chromium

pigments, green colors in paintings

were mostly based on copper pigments

like Azurite, Malachite or

Verdigris, however, the element

copper was not detected in the XRF

spectra of this painting. It is worth

noting, that similar XRF pigment

analysis is well suited to detect fake

paintings if the forger used modern

pigments like Titanium White (available

since ca. 1920) or various

Cadmium pigments (not available

before the very late 19 th Century), as it

was discovered in a number of cases of

art forgery. The most prominent case

might be the forger Wolfgang Beltracci

who specialized on fakes of Expressionism

painters from around 1900

and probably sold hundreds of fakes

into the art market. In one of his

forged paintings of the famous painter

Campendonk, the pigment Titanium

White was measured in a technical

investigation with XRF, which proved

that the painting was a fake and

thereby uncovered one of the largest

cases of art forgery.

In the landscape painting of

Figure 5, surprisingly a high amount

of mercury (an element, which is

umambiguously assigned to the red

pigment Cinnabar) was detected. The

idea, that Cinnabar could have been

used in one of the paint layers below

the visible surface was at hand. By

means of the digital X-ray radiography

of the painting, it was discovered that

the artist had used an older canvas

with a mythological or religious

figural scenery for his work (see

Figure 6) and that the overpainted

and hidden composition is well

consistent with the use of Cinnabar

pigment, which often occurs in (red)

clothes of the figures.

As it was stated above, X-ray

radiography is not limited to paintings

and this is shown in the following case

[13]. Near the village of Schortens

in Friesland, a part of North-West-

Germany, a large cemetery field from

the early middle-ages had been

discovered in the 1970’s. The archaeological

findings, attributed to a period

from the 5 th to the 12 th Century,

consisted of cinerary urns including a

variety of corroded metallic artefacts

and are conserved in museums today

(Landesmuseum Natur und Mensch

Oldenburg and Landesmuseum

Hannover). However, most of the

metallic artefacts were never investigated,

although the presumed keys,

buckles, knives or even swords given

to the graves of the dead would reveal

additional knowledge about the life in

these early populations of North-

West- Germany, before and during the

Christianisation phase. The effort to

restore such objects is very high and

restoration is under the risk of

damaging the objects during the

delicate procedures involved. Hence,

a non-destructive imaging by X-rays

was chosen in order to reveal first

insight into the corroded pieces and

prepare a decision basis for later

restoring.

As an example for the results,

Figure 7 shows the amazing pictures

of a so-called needle tubule, which

was an important part of women´s

equipment in the early middle ages,

| Fig. 6.

overpainted composition as well as structural information.

Research and Innovation

Radiation in Art and Cultural Heritage ı Frank Meissner and Andrea Denker

atw Vol. 65 (2020) | Issue 4 ı April

[9] Bildanalyse in der Kunst

A. Beck

in: Forschung mit Röntgenstrahlen

F.H.W. Heuck, E. Macherauch (Eds.)

Springer, Berlin, Heidelberg (1995)

ISBN 978-3-642-78842-0

[10] Die Bedeutung der Gemäldedurchleuchtung mit Röntgenstrahlen

für die Kunstgeschichte

C. Wolters

in: Veröffentlichungen zur Kunstgeschichte Bd. 3

Prestel-Verlag, Frankfurt (1938)

[11] https://www.nga.gov/features/bazille-hiddencompositions.html

Webpage of the National Gallery of Art, Washington,

date: Feb.17 th , 2020

[12] https://www.rijksmuseum.nl/en/the-first-scan

Webpage of the Rijksmuseum, Amsterdam,

date: Feb.14 th , 2020

[13] https://www.archaeologie-online.de/nachrichten/

kulturgut-unter-dem-roentgengeraet-4419/

Authors

Dr. Frank Meissner

TÜV NORD EnSys

Große Bahnstraße 31

22525 Hamburg

Prof. Dr. Andrea Denker

Helmholtz-Zentrum Berlin

Hahn-Meitner-Platz 1

14109 Berlin

RESEARCH AND INNOVATION 229

| Fig. 7.

in a cinerary urn shows that the tubule contains a needle. It was given to the buried ashes of its owner,

most likely a woman from the 5 th to 7 th century (Landesmuseum Natur und Mensch, Oldenburg)

usually tied to their belts. These

tubules contained a stitching needle

which was thus readily available for

sewing and repair work. By means of

digital X-ray radiography, the needle

inside the tubule and also some remnants

of a thread are clearly identified,

see Figure 7. Archeologists are

gaining information by these X-ray

images which would otherwise not be

available.

3 Summary

Nuclear methods and X-rays applications

are not limited to industry or

medicine, but have found entrance

into the investigation of art and

cultural heritage objects. Worldwide,

a number of institutes work on projects

or even support devoted working

groups in order to use reactor neutrons,

accelerator particle beams and

X-rays from synchrotrons or X-ray

tubes in the research of paintings and

historical artefacts. In the case of

X-rays, mobile equipment for radiography

and XRF analysis has large

advantages for valuable or non-transportable

objects since they can be

used on-site. Neutrons from reactor

facilities allow complementary techniques,

which reveal striking additional

information about the objects,

provided the objects are transported

to the reactor site. Some established

methods in art and cultural heritage

were described to shine on these interesting

radiation applications, which

are well suited to answer questions

deriving from art history, archeology,

conservators and many other professionals

in this field.

Literature

[1] Synchrotron Radiation and Neutrons in Art and Archeology,

9 th International Conference, 22-25 February 2021

in Los Angeles

[2] Why use neutrons?

Schillinger, B.

Restaur. Archäol. 8 (2015): 1–7

[3] Neutron Imaging in Cultural Heritage Research at the FRM II

Reactor of the Heinz Maier-Leibnitz Center

Schillinger, B.; Beaudet, A.; Fedrigo, A.; Grazzi, F.; Kullmer, O.;

Laaß, M.; Makowska, M.; Werneburg, I.; Zanolli, C.

J. Imaging 4 (2018): 22.

[4] Neutron activation autoradiography and scanning macro-XRF

of Rembrandt van Rijn’s Susanna and the Elders

(Gemäldegalerie Berlin): a comparison of two methods for

imaging of historical paintings with elemental contrast

M. Alfeld, C. Laurenze-Landsberg, A. Denker,

K. Janssens, P. Noble

Appl. Phys. A (2015) 119:795-805

[5] Scanning macro-x-ray fluorescence analysis and Neutron

Activation Auto Radiography: Complementary imaging

methods for the investigation of historical paintings

M. Alfeld, C. Laurenze-Landsberg, A. Denker,

K. Janssens, P. Noble

Berliner Beiträge zur Archäometrie, Kunsttechnologie und

Konservierungswissenschaft, Band 23 (2015): 9-14

[6] The Examination of Paintings by Rembrandt with Neutron

Autoradiography and a comparison of Neutron Autoradiography

with Scanning Macro-XRF

C. Laurenze-Landsberg

Restaurierung und Archäologie 8 (2015), 99-114

[7] Neutron Autoradiography of Paintings, ‘The Hermit’ by an

unknown artist and ‘Armida abducts the sleeping Rinaldo’

(c.~1637) by Nicolas Poussin

B. Schröder-Smeibidl, C. Laurenze-Landsberg,

C. Schmidt, L. A. Mertens

in: Non-destructive testing and analysis of museum objects

A. Denker, A. Adriaens, M. Dowsett, A. Giumlia-Mair (Editors)

Fraunhofer IRB Verlag, ISBN 978-3-8167-7178-4

[8] BENSC neutrons for “Cultural Heritage” Research:

Neutron Autoradiography of Paintings

C. Laurenze-Landsberg, L.A. Mertens,

C. Schmidt, B. Schröder-Smeibidl

Notiziario Neutroni e Luce di Sincrotrone 11 no. 1 (2006):

24-27

Research and Innovation

Radiation in Art and Cultural Heritage ı Frank Meissner and Andrea Denker

atw Vol. 65 (2020) | Issue 4 ı April

RESEARCH AND INNOVATION 230

WiN Germany

Price 2019

Studies on the Interaction of Plant Cells

with U(VI) and Eu(III) and

on Stress- induced Metabolite Release

Jenny Jessat, Susanne Sachs, Robin Steudtner and Thorsten Stumpf

The interaction of plant cells with U(VI) and Eu(III) was investigated as a function of exposure time and metal

concentration. Brassica napus (canola) cells were used in the experiments. For europium and uranium, an immobilization

by the plant cells could be observed in first instance, which can be attributed to sorption processes. During the

experiments an equilibrium state was reached, i.e. for none of the investigated concentrations a complete bio association

occurred. Especially for the examined concentration of 200 µM U(VI) a multi-stage bioassociation process was observed,

i.e. after the described bioassociation a new release of uranium by the cells occurred. By means of time-resolved laserinduced

fluorescence spectroscopy it could be shown that the U(VI) is complexed by cell metabolites in the course of

exposure. Several newly formed species could be detected. It can be assumed that metabolites released by plant cells in

response to heavy metal stress complex U(VI) and keep it in solution. Using a combination of solid phase extraction,

high-performance liquid chromatography and mass spectrometry, p-coumaric acid and fumaric acid were identified as

released metabolites and their complexation behavior with U(VI) was investigated.

| Fig. 1.

Schematic illustration of possible interaction processes of heavy metals

with a plant cell. (adapted from Francis 1998 [13])

Introduction

In Germany, the Ethics Committee on

Secure Energy Supply proposed the

phasing out of the use of nuclear

energy in 2011 and found its realization

possible within the next ten years.

[1] As a result, it was decided to shut

down all German nuclear power

plants by 2022. The decision for a

suitable repository site for high radioactive

nuclear waste is a major challenge

for politicians, energy supply

companies and society. It is the task

of science to understand and predict

the behavior of radionuclides in

the environment to create the basis for

a safety assessment and thus for

repository site selection. For a reliable

safety assessment of nuclear waste

reposi tories, it is necessary to consider

possible scenarios in which radionuclides

are released into the environment.

In this context, the transfer

behavior of the radionuclides from the

groundwater zone via the soil into the

plant is of importance. Radionuclides

can be accumulated by plants and

thus, they can enter the food chain.

This creates a health risk for humans

and animals. However, there is little

knowledge about the mechanisms of

interaction between radionuclides

and plants. Of course, there are some

studies on this topic [2–5], but in

many cases only transfer factors are

determined which do not provide any

information on the underlying processes

taking place. [5–7] It is therefore

a major goal to generate a molecular

process understanding in this

field.

Thus, one major objective of the

present work was to investigate the

time dependence of the bioassociation

of uranium (U(VI)) and europium

(Eu(III)) with Brassica napus (canola)

cells. These two elements were chosen

because uranium is a major component

of spent nuclear fuel rods and

europium can be used as an analogue

for trivalent actinides, like plutonium

(Pu(III)), americium (Am(III)) and

curium (Cm(III)). [8–10] Americium

and curium, in turn, are significantly

responsible for the long-lasting radiotoxicity

of the nuclear waste. [8]

Canola was selected because it is a

typical feed and crop plant in

Germany. It is also known for tolerating

high amounts of heavy metals

and is therefore a suitable model

organism for these studies. [7,11] The

suspension cell cultures used are

obtained from callus cultures. Callus

cells have the advantage that they are

able to synthesize typical secondary

metabolites that are also produced in

whole tissues. [12] It is also of interest

to investigate the formation of

metabolites that are released by the

cells as a response to the heavy metal

stress as well as to study the complexation

behavior of these metabolites

with uranium. These data are

required for an improved process

understanding and are the basis for

the modeling of the radionuclide

transfer in the environment up to the

food chain.

Therefore it is necessary to know

possible interaction processes of

plant cells with heavy metals including

radio nuclides, as illustrated

in Figure 1.

On the one hand there is the

sorption [14] of heavy metals on cell

walls and membranes, which takes

place passively and fast, on the other

hand there is the accumulation [15]

as an active process through which

heavy metals are taken up into the

cell. As a result of the release of bioligands

by the cell, heavy metals can

be complexed. This process influences

their solubility (biocomplexation).

[16,17] Due to biotransformation [18]

(usually that is a reduction) the oxidation

state of the heavy metal is

changed by the cell metabolism. For

uranium this could be a reduction

from U(VI) to U(IV). This reduction is

closely related to biomineralization,

which can lead to the formation of

insoluble metal precipitates. [11,19]

To put it simply, all processes with the

exception of complexation lead to an

immobilization of the heavy metals

and are therefore summarized under

the term bioassociation. Nevertheless,

it is possible to obtain information on

the individual processes, as will be

Research and Innovation

Studies on the Interaction of Plant Cells with U(VI) and Eu(III) and on Stress- induced Metabolite Release ı Jenny Jessat, Susanne Sachs, Robin Steudtner and Thorsten Stumpf

atw Vol. 65 (2020) | Issue 4 ı April

shown later. Due to these interactions,

stress reactions can be induced in the

plant cells. The heavy metals can act

directly as chemical stressors and

displace essential metal ions from the

active centers of enzymes or damage

proteins, especially those with thiol

groups. [20] They can also induce a

secondary form of stress – the oxidative

stress – by disturbing the

cellular redox status. This leads to

the formation of reactive oxygen

species, which in turn can damage

cell organelles. [20–22] Plants react

differently to stress. One possible

reaction is the formation of protective

metabolites that can affect the bioavailability

of heavy metals. [20,22]

To investigate the time-dependent

bioassociation behavior of U(VI) und

Eu(III) with canola, B. napus callus

cells (PC-1113 from DSZM, Braunschweig,

Germany) were transferred

to suspension cell cultures and

exposed to a phosphate-reduced cell

culture medium R [23] (R red ) with

different concentrations of U(VI) (20

and 200 µM) or Eu(III) (30 and

200 µM). Exposure times were thereby

varied between 1 and 72 h. At the end

of the exposure time the cells were

separated from the supernatants.

The metabolic activity of the cells

( vitality) was determined by the MTT

test [24] (MTT: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium

bromide). The supernatants were

analyzed concerning their heavy

metal content by ICP-MS (inductively

coupled plasma-mass spectrometry)

as well as regarding the speciation

(physico-chemical form) of U(VI) by

TRLFS (time-resolved laser-induced

fluorescence spectroscopy).

How plant cells react to radionuclides

and their analogues

As mentioned before, all cell-related

processes that can immobilize heavy

metals are called bioassociation. This

immobilization of U(VI) and Eu(III)

by B. napus cells can be compared for

different heavy metal concentrations.

Taking into account the metabolic

activity of the plant cells at the considered

exposure times, conclusions

can be drawn about the physiological

state of the cell and the reactions

taking place. For 20 µM U(VI) as well

as for 30 and 200 µM Eu(III) a comparable

behavior was observed: up

to about 24 h of exposure a rapid

increase of bioassociation occurs,

followed by an equilibrium adjustment.

This behavior is exemplary

shown in Figure 2 for the experiments

carried out with 30 µM Eu(III).

Two conclusions can be drawn

from this. On the one hand, the rapid

increase in bioassociation within the

first few hours suggests that biosorption

as a passive, fast process

plays an important role in the immobilization

of metals. However, it can

be assumed that with increasing

exposure time, other processes such

as bioaccumulation, biocomplexation

and bioprecipitation are also involved

in the overall process. Furthermore,

an equilibrium is reached after 24 h

and it is noticeable that for none of the

investigated concentrations 100 % of

the metal was bioassociated at equilibrium.

This means that there is no

complete immobilization of the metals

by the plant cells. This suggests that

bioprecipitated U(VI) remains unnoticed

as colloids in the supernatants

and/or that processes are actively

maintained by the cells to keep the

heavy metals out of or away from the

cells. For the lower U(VI) and Eu(III)

concentrations, cell vitality (metabolic

activity) remains at the level of

the control samples (100 %) over the

entire exposure period. It also turned

out, as expected, that the cell vitality

is increased for higher heavy metal

concentrations than for lower concentrations.

This difference can be

explained by the fact that plant cells

are exposed to increased stress due to

the higher heavy metal load and react

metabolically to it. The bioassociation

behavior of B. napus cells exposed

to 200 µM U(VI) differs from the

behavior described so far (shown as

an example in Figure 3).

Here, the initially rapid increase in

bioassociation can also be seen, which

is probably again mainly attributable

to biosorption. This is followed by a

decrease of the bioassociated amount

of uranium, i.e. as the exposure time

increases, less immobilized uranium

is present at or in the cells. Therefore,

it can be concluded that B. napus cells

show a multistage bioassociation process

in the presence of 200 µM U(VI).

At the same time, cell vitality shows

clear fluctuations during this period,

indicating metabolic processes induced

in the cell as a result of radionuclide

exposure. In the literature

such a multistage bioassociation process

could be observed for halophilic

archaea. [25] The release of U(VI)

indicates a biocomplexation. In the

literature it is mentioned that plant

cells react to heavy metal stress,

among other things, by releasing

protective metabolites, especially

flavonoids and phenols. [22,26] It can

therefore be assumed that, as a result

of the exposure of the cells to U(VI),

the release of protective metabolites

occurs, which complex U(VI) and thus

convert it into a more mobile physicochemical

form. Spectroscopic investigations

with cells and supernatants

were carried out in order to verify this.

Luminescence spectroscopy

shows that plant cells react

to uranium

The investigated system includes the

initial U(VI) containing nutrient

RESEARCH AND INNOVATION 231

| Fig. 2.

Bioassociation behavior and cell vitality of B. napus cells exposed to 30 µM

Eu(III) (mean values of 3 experiments). Cell vitalities are expressed

as a percentage of the cell vitality of the control samples.

| Fig. 3.

Bioassociation behavior and cell vitality of B. napus cells exposed to

200 µM U(VI) (1 experiment). Cell vitalities are expressed as a percentage

of the cell vitality of the control samples.

Research and Innovation

Studies on the Interaction of Plant Cells with U(VI) and Eu(III) and on Stress- induced Metabolite Release ı Jenny Jessat, Susanne Sachs, Robin Steudtner and Thorsten Stumpf

atw Vol. 65 (2020) | Issue 4 ı April

RESEARCH AND INNOVATION 232

| Fig. 4.

Luminescence spectra for the initial medium R red with 200 µM U(VI)

as well as cells and supernatants after 24 h exposure to 200 µM U(VI).

Spectra recorded after a delay of 0.1 µs.

medium as well as plant cells and

supernatants after exposure to U(VI).

These samples were examined by

means of TRLFS. Complexation with

inorganic and organic ligands present

in solution may change the speciation,

i.e. the physico-chemical form in

which the uranium is present in

solution. These changes in speciation

can be detected by TRLFS. Each U(VI)

species has a spectrum with characteristic

band positions and a typical

luminescence lifetime, which can

be determined by time-dependent

measurements. These data can be

used to determine how many and

which species occur in the system.

Reference substances can be used to

identify them. For biological samples,

cryo-TRLFS measurements are carried

out in particular, in which the samples

are cooled to -120 °C. This step is

necessary because numerous quenching

effects occur in the system due to

medium and cell components that

suppress the luminescence of U(VI).

At low temperatures, quenching

effects are suppressed as far as

possible and spectra can be obtained.

Figure 4 gives an overview of the

luminescence spectra for the initial

nutrient medium with 200 µM U(VI)

and cells and supernatants after 24 h

exposure to 200 µM U(VI).

It can be seen that the cell species

differs from the species in the medium

or the supernatant. According to the

literature [3] it can be assumed that

this cell species is formed by the

binding of UO 2

to cell membranes

or cell walls. Especially phosphate

groups are of importance for the

UO 2

sorption processes. A closer

look at the spectrum from the initial

medium and from the supernatant

after 24 h cell contact shows that

speciation in the medium changes

over time due to cell contact. From the

experiments it can be concluded that

the ((UO 2 ) 3 (OH) 5 ) + complex dominates

in the initial medium according

to the speciation calculations performed

(not shown) and the band

positions [2] of the luminescence

spectrum. However, the species that

dominates the luminescence in the

supernatant is different. The measurements

of the supernatants at different

exposure times showed that various

species occur in the supernatants over

time (not shown). Starting from the

medium species, the ((UO 2 ) 3 (OH) 5 ) +

complex [2], two more species appear

with increasing exposure time. Thus,

the sub-process of biocomplexation

could be detected spectroscopically

for B. napus cells. Both species represent

potential U(VI) complexes

with plant cell metabolites. To identify

these species it is necessary to identify

released metabolites and to investigate

their complexation behavior

with U(VI).

Plant cells release metabolites

in response to exposure

to uranium and europium

For the experiments on the enrichment

and identification of plant cell

metabolites only very high concentrations

of U(VI) and Eu(III) were

used and the exposure time was fixed

at 1 week in order to accumulate as

many metabolites as possible in the

nutrient medium. For the identification

of metabolites in the supernatants

after cell contact, sequentially

solid phase extraction, HPLC (highperformance

liquid chromatography)

and MS (mass spectrometry) measurements

were performed. For solid

phase extraction columns were used

that were suitable for enrichment of

phenolic compounds and flavonoids.

This procedure made it possible to

obtain chromatograms of the enriched

eluates from the extraction

(Figure 5).

| Fig. 5.

Chromatograms of solid phase extraction eluates of cell culture media after

plant cell exposure to 200 µM U(VI) or Eu(III) in comparison to those of

control samples. Peaks that are new or exhibit higher intensities compared

to the control sample are marked.

Of particular interest are peaks in

the chromatograms, which either

show increased intensities or are new,

compared to the control sample. A

first peak assignment is possible by

measuring reference compounds by

HPLC and comparing their retention

times with those found for the eluates

from the solid phase extraction. In the

literature, phenolic compounds and

flavonoids in particular are mentioned

as typical plant metabolites that are

exuded in response to heavy metal

stress. [21,26] In addition, however,

smaller molecules such as organic

acids or amino acids, peptides and

amines are also mentioned. [21] A

number of representatives from these

mentioned substance classes have

therefore been measured by HPLC.

Peaks, which matched in their retention

times for reference and solid

phase extraction eluates were examined

more closely. The cor responding

peaks were fractionated and two metabolites

could be identified using MS:

p-coumaric acid and fumaric acid.

However, the investi gation of the

complexation behavior of these

compounds with U(VI) showed that

these substances are not involved in

the formation of the two species

identified in the TRLFS measurements

of the supernatants. Therefore,

further investigations on metabolite

release are still necessary. However,

a complexation constant could be

obtained from the complexation

experiments with fumaric acid, which

will be used for calculations.

Summary

The investigation of the timedependent

bioassociation behavior as

well as the spectroscopic, spectrometric

and chromatographic investigation

of the formed cell metabolites

and metal species led to molecular

understanding of the interaction of

Research and Innovation

Studies on the Interaction of Plant Cells with U(VI) and Eu(III) and on Stress- induced Metabolite Release ı Jenny Jessat, Susanne Sachs, Robin Steudtner and Thorsten Stumpf

atw Vol. 65 (2020) | Issue 4 ı April

the repository-relevant elements uranium

and europium (as analogue for

tri valent actinides) with B. napus.

When these elements are released

from a repository site into the environment,

they can initially be immobilized

via bioassociation with plants,

mainly by binding to the cell surface.

As a result, these elements may enter

the food chain and create a health risk

for the population. Furthermore, in

case of U(VI) exposure a release and

thus mobilization of uranium with the

involvement of metabolites is observed.

This can contribute to a higher

bioavailability for, e.g. soil microorganisms

and to the transfer of

uranium in the environment. It can be

assumed that, in addition to uranium,

other actinides are also mobilized by

interactions with plants.

Results of this study contribute

to an enhanced understanding of the

actinide uptake into plants on a

molecular level. Such data are

necessary to improve biogeochemical

models to predict the transfer of these

elements in the environment, which

enables the assessment of more

reliable radiation doses with lower

uncertainties.

[13] A. J. Francis, J. Alloys Compd. 1998, 271–273, 78–84.

[14] M. Vogel, A. Günther, A. Rossberg, B. Li, G. Bernhard, J. Raff,

Sci. Total Environ. 2010, 49, 384–395.

[15] S. Singh, R. Malhotra, B. S. Bajwa, Radiat. Meas. 2005, 40,

666–669.

[16] A. Günther, G. Geipel, G. Bernhard, Radiochim. Acta 2006,

94, 845–851.

[17] A. Günther, R. Steudtner, K. Schmeide, G. Bernhard,

Radiochim. Acta 2011, 99, 535–542.

[18] K. Viehweger, G. Geipel, G. Bernhard, Biometals 2011, 24,

1197–1204.

[19] J. Misson, P. Henner, M. Morello, M. Floriani, T. Wu,

J.-L. Guerquin-Kern, L. Février, Environ. Exp. Bot. 2009, 67,

353–362.

[20] E. Weiler, L. Nover, Allgemeine Und Molekulare Botanik,

Georg Thieme Verlag, Stuttgart, 2008.

[21] O. Sytar, A. Kumar, D. Latowski, P. Kuczynska, K. Strzałka,

M. N. V. Prasad, Acta Physiol. Plant. 2013, 35, 985–999.

[22] A. Emamverdian, Y. Ding, F. Mokhberdoran, Y. Xie,

Sci. World J. 2015, 2015, 1–19.

[23] https://www.dsmz.de/fileadmin/Bereiche/PlantCellLines/

Dateien/R.pdf, zuletzt aufgerufen am 20.08.2018.

[24] T. Mosmann, J. Immunol. Methods 1983, 65, 55–63.

[25] M. Bader, K. Müller, H. Foerstendorf, B. Drobot, M. Schmidt,

N. Musat, J. S. Swanson, D. T. Reed, T. Stumpf, A. Cherkouk,

J. Hazard. Mater. 2017, 327, 225–232.

[26] K. Viehweger, Bot. Stud. 2014, 55, 1–12.

Authors

M. Sc. Jenny Jessat,

Dr. Susanne Sachs,

Dr. Robin Steudtner,

Prof. Dr. Thorsten Stumpf

Helmholtz-Zentrum

Dresden-Rossendorf

Institute of Resource Ecology

Bautzner Landstraße 400

01328 Dresden

Germany

RESEARCH AND INNOVATION 233

Acknowledgement

The authors thank S. Beutner and

S. Bachmann for performing the

ICP-MS measurements as well as

M. Raiwa from the Institute of Radioecology

and Radiation Protection,

Leibniz University Hannover for

performing the MS measurements.

The work is part of the project

“TRANS-LARA”, which is funded by

the Federal Ministry of Education and

Research under contract number

02NUK051B.

References

[1] K. Töpfer, M. Kleiner, Deutschlands Energiewende –

Ein Gemeinschaftswerk Für Die Zukunft, Berlin, 2011.

[2] S. Sachs, G. Geipel, F. Bok, J. Oertel, K. Fahmy,

Environ. Sci. Technol. 2017, 51, 10843–10849.

[3] A. Günther, G. Bernhard, G. Geipel, T. Reich, A. Roßberg,

H. Nitsche, Radiochim. Acta 2003, 91, 319–328.

[4] S. D. Ebbs, D. J. Brady, L. V Kochian, J. Exp. Bot. 1998, 49,

1183–1190.

[5] L. Laroche, P. Henner, V. Camilleri, M. Morello,

J. Garnier-Laplace, Radioprotection 2005, 40, 33–39.

[6] F. V. Tomé, P. B. Rodríguez, J. C. Lozano, Chemosphere 2009,

74, 293–300.

[7] P. Chang, K. W. Kim, S. Yoshida, S. Y. Kim,

Environ. Geochem. Health 2005, 27, 529–538.

[8] M. Salvatores, Physics and Safety of Transmutation Systems –

A Status Report, Nuclear Energy Agency, Paris, 2006.

[9] D. Westlén, Prog. Nucl. Energy 2007, 49, 597–605.

[10] Z. Zha, D. Wang, W. Hong, L. Liu, S. Zhou, X. Feng, B. Qin,

J. Wang, Y. Yang, L. Du, et al., J. Radioanal. Nucl. Chem.

2014, 301, 257–262.

[11] J. Laurette, C. Larue, I. Llorens, D. Jaillard, P.-H. Jouneau,

J. Bourguignon, M. Carrière, Environ. Exp. Bot. 2012, 77,

87–95.

[12] N. V. Zagoskina, E. A. Goncharuk, A. K. Alyavina, Russ. J.

Plant Physiol. 2007, 54, 237–243.

Research and Innovation

Studies on the Interaction of Plant Cells with U(VI) and Eu(III) and on Stress- induced Metabolite Release ı Jenny Jessat, Susanne Sachs, Robin Steudtner and Thorsten Stumpf

atw Vol. 65 (2020) | Issue 4 ı April

234

KTG INSIDE

Inside

KTG-Fachgruppe Stilllegung und Entsorgung

Die KTG ist aktuell in sechs Fachgruppen untergliedert, in

denen sich die KTG-Mitglieder mit Schwerpunktthemen

der Kerntechnik und verwandter Fachgebiete beschäftigen

können.

Die KTG-Fachgruppe Stilllegung und Entsorgung

beschäftigt sich dabei mit allen Themen und Fragestellungen,

die sich aus der Planung und Durchführung von

Stilllegungs- und Rückbauprojekten kerntechnischer

Anlagen sowie aus den Themengebieten Management und

Zwischenlagerung radioaktiver Abfälle ergeben.

Die Arbeit innerhalb der Fachgruppe, z. B. die Vorbereitung

und Durchführung von Exkursionen zu Rückbaustandorten,

die Teilnahme an Fachdiskussionen sowie

die Mitarbeit bei der Lösung spezifischer Fragestellungen

erfolgt überwiegend durch die fünf Arbeitsgruppen

1. Genehmigungs- und Freigabeverfahren,

2. Abfallmanagement,

3. Zwischenlagerung (LAW/MAW und HAW),

4. Radiologische Charakterisierung und

5. Rückbautechnologien.

Mit ca. 490 Mitgliedern ist die Fachgruppe aktuell die

mitgliederstärkste Fachgruppe innerhalb der KTG. Der

Vorstand der Fachgruppe wird alle 5 Jahre neu gewählt

und besteht aus insgesamt 4 Mitgliedern. Die Tätigkeiten

innerhalb der Arbeitsgruppen werden jeweils durch einen

Arbeitsgruppenleiter organisiert.

KTG-Mitglieder, die sich an einer Mitarbeit in der

Fachgruppe bzw. in einer der fünf Arbeitsgruppen

interessieren, sind herzlich eingeladen, diesbezüglich

Kontakt mit dem Sprecher des Vorstandes Andreas Loeb

(entsorgung@ktg.org) oder den Leitern der Arbeitsgruppen

aufzunehmen. Weitere Informationen und

die Kontaktdaten der Vorstandsmitglieder und der

Arbeitsgruppenleiter sind auf der Homepage der KTG

(www.ktg.org) zu finden.

Andreas Loeb

Sprecher der KTG-Fachgruppe Stilllegung und Entsorgung

Herzlichen Glückwunsch!

Die KTG gratuliert ihren Mitgliedern sehr herzlich zum Geburtstag

und wünscht ihnen weiterhin alles Gute!

Wenn Sie künftig eine

Erwähnung Ihres

Geburtstages in der

atw wünschen, teilen

Sie dies bitte der KTG-

Geschäftsstelle mit.

KTG Inside

Verantwortlich

für den Inhalt:

Die Autoren.

Lektorat:

Natalija Cobanov,

Kerntechnische

Gesellschaft e. V.

(KTG)

Robert-Koch-Platz 4

10115 Berlin

T: +49 30 498555-50

F: +49 30 498555-51

E-Mail:

natalija.cobanov@

ktg.org

www.ktg.org

Mai 2020

35 Jahre | 1985

04. Nicole Koch, Mannheim

45 Jahre | 1075

21. Siewert Joswig, Beidentleth

55 Jahre | 1965

27. Dipl.-Ing. Thomas Glaab, Kahl

60 Jahre | 1960

19. Dr. Thomas Walter Tromm,

Walzbachtal-Jöhlingen

27. Hubert Reisinger, Gundremmingen

75 Jahre | 1945

11. Dipl.-Ing. Dieter Kreckel, Mainz

30. Dr. Klaus Kasper, Essen

76 Jahre |1944

12. Peter Faber, Rödermark

77 Jahre | 1943

03. Dipl.-Ing. Hans Lettau, Effeltrich

22. Dr. Wolfgang Schütz, Bruchsal

24. Dipl.-Ing. Rudolf Weh, Stephanskirchen

78 Jahre | 1942

09. Dr. Egbert Brandau, Alzenau

28. Dr. Wolf-Dieter Krebs, Bubenreuth

78 Jahre | 1942

05. Hans-Bernd Maier, Aschaffenburg

11. Dr. Erwin Lindauer, Köln

17. Dr. Heinz-Peter Holley, Forchheim

79 Jahre | 1941

08. Prof. Dr.-Ing. Helmut Alt, Aachen

80 Jahre | 1940

15. Dipl.-Phys. Ludwig Aumüller, Freigericht

24. Dipl.-Ing. Herbert Krinninger,

Bergisch Gladbach

81 Jahre | 1939

04. Dipl.-Ing. Norbert Albert, Ettlingen

82 Jahre | 1938

13. Dipl.-Ing. Otto A. Besch, Geesthacht

13. Dr. Heinrich Werle, Karlsdorf-Neuthard

16. Dr. Hans-Dieter Harig, Hannover

21. Dr. Hans Spenke, Bergisch Gladbach

83 Jahre | 1937

06. Dr. Peter Strohbach, Mainaschaff

26. Dipl.-Ing. Rüdiger Müller, Heidelberg

27. Dr. Johannes Wolters, Düren

28. Dipl.-Ing. Heinz E. Häfner, Bruchsal

85 Jahre | 1935

08. Dipl.-Ing. Klaus Wegner, Hanau

29. Dipl.-Ing. Karlheinz Orth, Marloffstein

86 Jahre | 1934

11. Dr. Eckhart Leischner, Rodenbach

14. Dr. Alexander, Warrikoff,

Frankfurt/Main

26. Dr. Günter Kußmaul, Manosque

87 Jahre | 1933

04. Dr. Klaus Wiendieck, Baden-Baden

25. Dr. Reinhold Mäule, Walheim

90 Jahre | 1930

09. Dr. Hans-Jürgen Hantke, Kempten

92 Jahre | 1928

10. Dr. Heinz Büchler, Sankt Augustin

96 Jahre | 1924

22. Prof. Dr. Fritz Thümmler, Karlsruhe

KTG Inside

atw Vol. 65 (2020) | Issue 4 ı April

Top

Foratom calls for the EU

to recognise nuclear

as a strategic industry

(foratom) Foratom welcomes the

European Commission’s goal of ensuring

Europe’s industry is fit for the

ambitions of today and prepared for

the realities of tomorrow, as outlined

in its Industrial Strategy published

yesterday. The European nuclear

industry stands ready to help Europe

achieve its goals in terms of providing

clean energy and maintaining Europe’s

competitiveness.

As highlighted in the Industrial

Strategy, one of the key challenges

ahead is ensuring that Europe’s

industry has access to a secure supply

of clean energy at a competitive

price. This is crucial for maintaining

Europe’s competitiveness.

“Nuclear energy can contribute to

making this a reality” states Yves

Desbazeille, FORATOM’s Director

General. “Not only is it low-carbon,

it is also flexible, dispatchable and

cost-effective”.

Indeed, nuclear energy is vital in

this respect as it can help:

p Maintain the competitiveness of

Europe’s industry as energy often

accounts for a significant share

of manufacturing costs,

p Decarbonise industry and thus

contribute towards the 2050

carbon neutrality target,

p Provide industry with the energy

it needs when it needs it, which

is particularly important for

processes which run 24/7,

p Other industries by offering alternative

sources of decarbonised

energy such as hydrogen and heat

(sector coupling).

The European nuclear industry also

contributes significantly to the EU’s

economy as it currently sustains

around 1 million jobs in the EU and

generates around € 450 billion in GDP

(Economic and Social Impact report,

Deloitte 2019. EU-27 & UK).

This is why it is essential that

EU decision-makers take steps to

| The Versatile Test Reactor can help Unlock the

Future of Carbon-Free Energy (Photo credit:

U.S. DOE)

support the nuclear sector’s important

role within the EU economy. This

includes a stable EU policy framework,

and one which encourages

investment in high-overnight costs,

low-carbon technologies. Significant

support to R&D and innovation as

well as increase funding for research

into both current and future nuclear

technologies such as SMRs, is also key

to prepare for the future, develop new

applications and breakthrough designs

and technologies.

| www.foratom.org (20791509)

Company News

Framatome opens new

research and operations center

and expands Intercontrôle

(framatome) Framatome held a

ceremonial ribbon-cutting event in

Cadarache, France, to mark the

opening of its new engineering

research and operations center and

the expansion of Intercontrôle, a

Framatome subsidiary that specializes

in automated non-destructive testing.

More than 100 customers, partners

and employees attended the celebration.

Framatome’s new engineering

research and operations center is

home to a multidisciplinary engineering

team responsible for carrying out

construction, safety reviews and

dismantling projects on behalf of the

French Alternative Energies and

Atomic Energy Commission (CEA)

and TechnicAtome. This team also

works on the ITER nuclear fusion

project, responsible for the Tokamak

installation as part of a consortium

with Chinese partners.

| www.framatome.com (20791519)

GNS takes over

Eisenwerk Bassum GmbH

(gns) On 21 February 2020 GNS

Gesellschaft für Nuklear-Service mbH

took over 100 % of Eisenwerk Bassum

GmbH. The company with its 106

employees at the Bassum and Peenemünde

sites will continue to provide

the proven supplies and services as an

independent GmbH under the name

Eisenwerk Bassum. The management

has informed the staff about this in

works meetings at both locations.

The previous owners, Edda

Beckedorf and Hartmut Grunau, will

remain active in the company. In

future, the management will consist

of Hartmut Grunau as technical and

Georg Büth as commercial managing

director. “Eisenwerk Bassum GmbH

will be strengthened in view of the

numerous development and approval

procedures that are still required and

the ability to supply all customers

will be further secured,” explained

Hartmut Grunau on the occasion of

the signing of the contract. Our aim is

to continue the reliable cooperation

with all existing customers,” adds

Georg Büth, commercial managing director

of GNS and new member of the

management board of Eisenwerk Bassum.

"In addition, the internationalisation

of GNS will open up

opportunities for Eisenwerk Bassum

GmbH and all its employees to develop

further markets in Europe and

beyond.“

| www.gns.de (20791520)

Westinghouse eVinci Micro

reactor awarded funding

for Mobile Reactor Design

(westnuc) Westinghouse Electric

Company announced that its eVinci

micro reactor was awarded funding

from the U.S. Department of Defense’s

(DoD) Project Pele, a mobile nuclear

reactor prototyping program. The

funding will be used to finalize the

design for a prototype of Westinghouse’s

defense-eVinci (DeVinci)

mobile nuclear power plant (MNPP).

“We are honored to participate in this

strategically important program,” said

Patrick Fragman, President and

Chief Executive Officer, Westinghouse

Electric Company. “Mobile nuclear

reactors offer clean, flexible, and

reliable power for our customers. We

are now developing technology to

provide energy security for the

Department of Defense, bringing our

exciting concept to realization.”

Westinghouse’s eVinci micro reactor

is a next-generation, very small

modular reactor for decentralized

generation markets. The DoD’s mobile

nuclear reactor prototype project

expands upon the transportable capabilities

of the eVinci micro reactor by

allowing for operations via a mobile

platform utilizing standard military

transportation. The eVinci micro

reactor is designed to operate for

many years, eliminating the need for

frequent refueling. The innovative

passive safety features of the design

allow the reactor to operate and

achieve safe shutdown without the

need for additional controls, external

power source or operator intervention,

enabling highly autonomous

operation.

| www.westinghousenuclear.com

(20791522)

235

NEWS

News

atw Vol. 65 (2020) | Issue 4 ı April

Operating Results December 2019

236

NEWS

Plant name Country Nominal

capacity

Type

gross

[MW]

net

[MW]

Operating

time

generator

[h]

Energy generated, gross

[MWh]

Month Year Since

commissioning

Time availability

[%]

Energy availability

[%] *) Energy utilisation

[%] *)

Month Year Month Year Month Year

OL1 Olkiluoto BWR FI 910 880 744 689 506 7 810 262 269 465 470 100.00 97.48 99.93 96.77 100.73 96.91

OL2 Olkiluoto BWR FI 910 880 744 689 612 7 467 543 259 364 086 100.00 93.18 100.00 92.76 100.75 92.66

KCB Borssele PWR NL 512 484 744 380 093 6 259 745 167 981 434 99.56 87.74 99.55 87.68 100.04 85.16

KKB 1 Beznau 7) PWR CH 380 365 744 286 693 2 974 710 130 308 820 100.00 89.75 100.00 89.60 101.47 89.29

KKB 2 Beznau 7) PWR CH 380 365 744 284 932 2 946 376 137 296 783 100.00 88.93 100.00 88.78 100.85 88.42

KKG Gösgen 7) PWR CH 1060 1010 744 793 809 8 240 707 322 116 235 100.00 89.44 99.99 89.00 100.66 88.75

KKM Mühleberg BWR CH 390 373 468 160 570 3 208 590 130 612 905 100.00 100.00 91.32 99.32 87.97 96.97

CNT-I Trillo PWR ES 1066 1003 744 760 320 8 456 358 255 748 026 100.00 91.87 99.94 91.56 95.25 89.97

Dukovany B1 PWR CZ 500 473 744 372 627 3 654 690 115 884 184 100.00 85.29 100.00 84.84 100.17 83.44

Dukovany B2 PWR CZ 500 473 744 370 332 2 809 147 111 043 318 100.00 65.65 100.00 65.15 99.55 64.14

Dukovany B3 PWR CZ 500 473 744 370 311 3 753 696 110 251 736 100.00 87.96 99.92 87.65 99.55 85.70

Dukovany B4 1,2) PWR CZ 500 473 571 283 155 4 263 688 110 706 957 76.75 97.90 76.22 97.73 76.12 97.34

Temelin B1 4) PWR CZ 1080 1030 520 529 271 7 553 771 121 914 813 69.89 81.35 65.83 80.80 65.75 79.71

Temelin B2 PWR CZ 1080 1030 744 814 518 8 210 101 117 482 618 100.00 86.23 100.00 86.04 101.18 86.62

Doel 1 PWR BE 454 433 0 0 2 291 598 137 736 060 0 56.73 0 56.39 0 56.31

Doel 2 PWR BE 454 433 0 0 2 533 531 136 335 470 0 64.55 0 63.46 0 63.41

Doel 3 PWR BE 1056 1006 744 806 677 7 979 166 263 111 650 100.00 85.76 100.00 85.26 102.15 85.78

Doel 4 PWR BE 1084 1033 744 812 318 9 264 865 269 638 275 100.00 100.00 99.96 97.16 99.35 96.01

Tihange 1 PWR BE 1009 962 698 692 594 8 716 566 307 547 424 93.79 99.47 91.77 99.28 92.37 98.72

Tihange 2 PWR BE 1055 1008 744 780 282 3 402 589 258 054 519 100.00 38.55 100.00 37.70 100.40 37.11

Tihange 3 PWR BE 1089 1038 744 807 404 9 335 304 280 562 577 100.00 99.98 99.98 99.43 100.31 98.37

Plant name

Type

Nominal

capacity

gross

[MW]

net

[MW]

Operating

time

generator

[h]

Energy generated, gross

[MWh]

Time availability

[%]

Energy availability

[%] *) Energy utilisation

[%] *)

Month Year Since Month Year Month Year Month Year

commissioning

KBR Brokdorf DWR 1480 1410 744 953 817 10 153 213 360 721 023 100.00 87.69 94.25 82.34 86.26 78.01

KKE Emsland DWR 1406 1335 744 1 019 334 10 781 232 357 600 201 100.00 89.20 100.00 89.12 97.43 87.54

KWG Grohnde DWR 1430 1360 744 1 004 034 10 700 632 388 274 846 100.00 90.06 99.99 89.82 93.85 84.89

KRB C Gundremmingen SWR 1344 1288 744 987 844 10 381 798 341 323 552 100.00 89.15 98.31 88.54 98.33 87.75

KKI-2 Isar DWR 1485 1410 744 1 024 900 10 411 410 340 238 244 100.00 94.03 100.00 87.18 98.61 85.04

GKN-II Neckarwestheim DWR 1400 1310 744 1 069 425 12 036 656 365 762 469 100.00 95.95 100.00 95.68 96.45 92.17

KKP-2 Philippsburg 4) DWR 1468 1402 739 840 227 10 606 307 376 767 462 99.33 89.63 97.85 89.31 75.15 81.12

Net-based values

(Czech and Swiss

nuclear power

plants gross-based)

Refueling

Inspection

Repair

Stretch-out-operation

Stretch-in-operation

Hereof traction supply

Incl. steam supply

New nominal

capacity since

January 2016

Data for the Leibstadt

(CH) NPP will

be published in a

further issue of atw

BWR: Boiling

Water Reactor

PWR: Pressurised

Water Reactor

Source: VGB

Organisations

Comment on

decarbonisation in Germany

(nuklearia) Rainer Reelfs, Stellvertretender

Vorsitzender der Nuklearia

e.V. zur Energiestrategie in Deutschland:

„Um das Ziel der Dekarbonisierung

Deutschlands zu erreichen,

sollte eine Expertenkommission eingerichtet

werden, die den aktuellen

Stand der deutschen Energieversorgung

überprüft und mit den erklärten

Klimazielen abgleicht. Wenn dies

erfolgt, wird sich schnell herausstellen,

dass der gleichzeitige Verzicht

auf Kohle und Kernenergie die Sicherheit

der Stromversorgung weitgehend

gefährdet. Folglich, kann bei einem

Kohleausstieg diese nur durch Kernenergie

ersetzt werden.

Was eine mögliche Rückkehr zur

Atomenergie in Deutschland angeht,

ist zu verstehen, dass die Politiker

zuerst die Energieversorgungssicherheit,

die Verfügbarkeit von Strom und

den Verzicht auf den Einsatz von

Kohle sicherstellen müssen. So ist

die Aussage von Sachsens Ministerpräsidenten

Michael Kretschmer, dass

Deutschland die Kompetenzen im

Kernenergiebereich erhalten sollte,

auch wenn keine neuen KKW gebaut

werden, als Stimmungstest für die

öffentliche Meinung zu verstehen.

Tatsache ist, dass die Kernenergie ist

die einzige dauerhaft verfügbare und

quasi unerschöpfliche Energiequelle

mit geringen CO 2 -Emissionen ist. Sie

ist zudem in der Lage, den Markt für

Strom und Wärme zu bedienen. Erst

mit der Kernenergie ist in Deutschland

eine nachhaltige Dekarbonisierung

möglich.

Wenn man von der Strategie der

EU-Kommission „Green Deal“ spricht,

ist festzustellen, dass sich ihre Umsetzung

negativ auf die deutsche

Wirtschaft auswirken wird. Man muss

dazu erkennen, dass Wind- und Solarenergie

erst aufgrund eines hohen

Niveaus von direkten und indirekten

Subventionen auf dem Markt existieren

können.“

| www.nuklearia.de

People

Professor Karl Kußmaul –

90. Geburtstag

(uni) Der Reutlinger Karl Kußmaul

begeht am 8. April 2020 seinen 90.

Geburtstag im Kreise seiner Familie.

An der Universität Stuttgart hat er

als Ordinarius für Materialprüfung,

Werkstoffkunde und Festigkeitslehre

und Direktor der Staatlichen Materialprüfungsanstalt

(MPA Stuttgart) 22

Jahre lang gewirkt und ist 1998

emeritiert worden. Auch danach war

News

atw Vol. 65 (2020) | Issue 4 ı April

es ihm möglich, seine Projekte und

Vorstellungen als Berater und Gutachter

bis heute fortzuführen.

Eine offizielle Würdigung seiner

Bedeutung und weitgespannten internationalen

Aktivitäten in Europa,

Amerika, Asien und Südafrika, findet

am 6. Oktober 2020 im Rahmen des

46. MPA-Seminars in der Filderhalle,

Leinfelden-Echterdingen, im Beisein

von Vertretern aus Politik und Wirtschaft

statt. Die jährlich stattfindenden

MPA-Seminare zählen zu den

weltweit wichtigsten Konferenzen, bei

denen sich Fachleute über innovative

Werkstoffkonzeptionen und Sicherheitsfragen

hochbeanspruchter Bauteile

im Anlagen- und Energiesektor

austauschen.

Hochaktuell sind die von Kußmaul

bereits im Jahr 1990 großangelegten

sicherheitstechnischen und experimentellen

MPA-Untersuchungen zur

Ermöglichung einer auf Wasserstoff

basierenden Energieversorgung, die

besonders im Verkehrswesen eine

nachhaltige Perspektive aufzeigen.

Kußmauls Wirken ist durch seine

außerordentliche Breite geprägt: so

ist die Berstsicherheit für die unterschiedlichen

Ariane-Raketen ebenso

an der MPA nachgewiesen worden,

wie er auch das entscheidende Genehmigungsgutachten

im Bereich des

Stahlbaus für das Centre Pompidou

in Paris erstellte. Genehmigungsbehörden

und Verwaltungsgerichte

haben den unabhängigen Sicherheitsexperten

als Gutachter und Zeugen

bestellt. Entscheidend waren seine

differenzierten und wissenschaftlich

fundierten Aussagen in den Kernenergieprozessen.

Kußmaul ist mehrfach ausgezeichnet

worden. 1986 hat er das

Bundes verdienstkreuz Erster Klasse

erhalten. 1988 wurde ihm eine Ehrenprofessur

in China am Nanking Institut

für Chemische Technologie verliehen.

1989 wurde er Ehrendoktor

der Technischen Wissenschaften

der Technischen Universität Graz.

1997 folgte die Verdienstmedaille des

Landes Baden-Württemberg.

Zeichen der Wertschätzung sind

auch der Erfahrungsaustausch mit

dem Kurchatov Institut der Russischen

Akademie der Wissenschaften,

das Ersuchen des französischen Hochkommissars

für Atomenergie um

Mitarbeit in der „Kommission zur

Definition der Voraussetzungen, unter

denen ein Universitätsunterricht für

das Atomwesen gestaltet werden

kann“, die Tätigkeit für die IAEA in

Wien und in Sofia, Bulgarien, als

Leiter des internationalen „Workshops

Uranium

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

140.00

120.00

100.00

80.00

60.00

40.00

20.00

0.00

1980

Jan. 2009

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

Jan. 2010

1985

Jan. 2011

1990

Jan. 2012

Jan. 2013

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

on Koslodui Unit 1 Pressure Vessel

Integrity“. Diese Druckbehälterart ist

insofern von Bedeutung, als sich noch

bis heute Reaktoren der 1. Generation

mit der Technik der sechziger Jahre

im russischen Kernkraftwerk Kola

befinden. Zu nennen sind auch die

OECD in Paris, sowie das Angebot der

UNESCO für die in Arbeit befindliche

„Enzyklopädie für Systeme zur

Erhaltung des menschlichen Lebens in

einer zum Leben ungeeigneten Umgebung“

die Position des Honorary

Editors für den Teil Energiewerkstoffe

und Reaktoren einzunehmen, sowie

als Hauptherausgeber der Redaktion

mitzuwirken.

| www.mpa.uni-stuttgart.de

(20791534)

Market data

(All information is supplied without

guarantee.)

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-$/

1995

Jan. 2014

2000

Jan. 2015

Jan. 2016

2005

Jan. 2017

) 1

2010

Jan. 2018

Jan. 2019

2015

Jan. 2020

2020

Year

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

Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020

* Actual nominal USD prices, not real prices referring to a base year. Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020

| Uranium spot market prices from 1980 to 2020 and from 2009 to 2020. 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]

180.00

26.00

) 1 ) 1

160.00

140.00

120.00

100.00

80.00

60.00

40.00

20.00

0.00

Jan. 2021

Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020

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

140.00

) 1

120.00

100.00

80.00

60.00

40.00

20.00

0.00

24.00

22.00

20.00

18.00

16.00

14.00

12.00

10.00

Jan. 2009

8.00

6.00

4.00

2.00

0.00

Jan. 2009

Jan. 2010

kg U], Separative work [US-$/SWU

(Separative work unit)].

Jan. 2011

Jan. 2012

Jan. 2013

2017

p Uranium: 19.25–26.50

p Conversion: 4.50–6.75

p Separative work: 39.00–50.00

2018

p Uranium: 21.75–29.20

p Conversion: 6.00–14.50

p Separative work: 34.00–42.00

2019

January to June 2019

p Uranium: 23.90–29.10

p Conversion: 13.50–18.00

p Separative work: 41.00–49.00

July to December 2019

p Uranium: 24.50–26.25

p Conversion: 18.00–23.00

p Separative work: 47.00–52.00

2020

January 20202

p Uranium: 24.10–24.90

p Conversion: 22.00–23.00

p Separative work: 48.00–51.00

| Source: Energy Intelligence

www.energyintel.com

Jan. 2014

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

Jan. 2015

Jan. 2016

Jan. 2017

Jan. 2018

Jan. 2019

Jan. 2020

Jan. 2021

Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020

| Separative work and conversion market price ranges from 2009 to 2020. 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 2020

Jan. 2021

237

NEWS

News

atw Vol. 65 (2020) | Issue 4 ı April

238

NUCLEAR TODAY

John Shepherd is a

freelance journalist

and communications

consultant.

Sources:

Franz Timmermans

interview

https://bit.ly/39APlV0

NEA Nuclear Energy

Date 2019

https://bit.ly/38xxLjt

Barakah-1

announcement

https://bit.ly/2IvGatm

Cards Still Stacked Against Nuclear

in Green Investment Deal

John Shepherd

The launch a few weeks ago of proposals for a European Climate Law should have been a clarion call towards ushering

in a cleaner, greener future – but instead of a fanfare for change. I heard only another requiem for common sense.

I had initially listened with anticipation as Frans

Timmermans, the European Commission’s executive

vice-president, opened a ‘high-level public conference’ on

the European Union’s so-called Green Deal investment

plan and the proposals for the new climate law.

The background to the conference was the Commission’s

decision to enshrine in the law the goal of achieving

net zero carbon emissions by 2050. This is without doubt a

worthy ambition for Europe that can impact the wider

world. However, the conference appears to have been yet

another missed opportunity to demonstrate that nuclear

technology might finally be judged on its merits in the

climate debate rather than political ideology.

One might have expected better of such a grand

European initiative, yet such hopes were dashed in favour

of disappointment.

According to the Commission, it plans at least € 1

trillion in sustainable investments over the next decade to

support its Green Deal, but transition fund money under

the plan will not contribute towards building nuclear

power plants.

Vice-president Timmermans himself told the conference

that, in support of the climate law, Europe has “the

science and technology and we can certainly find the

money”. But he neglected to say money would not be fairly

allocated.

He said the law would “give that extra bit of security”

some investors needed to make “the jump into the future”

in terms of providing technological projects that would

support the EU’s goal of achieving climate neutrality and a

substantial reduction of emissions by 2030. But what

investor will feel secure in pursuing advances in clean,

nuclear energy development without a level playing field

on which to compete for funds?

We have heard warm words indeed from the Commissioner,

but they offer only cold comfort for potential

nuclear technology investors. Indeed, the Commissioner

was quoted as saying in a recent interview that while

nuclear has a positive effect on greenhouse gas emissions,

he believed nuclear was “not sustainable”.

The high-level conference compounded its disdain for

keeping an open mind on climate-friendly technologies

when it held two debates with panelists. Not one nuclear

industry representative was on either panel, although a

solar power company CEO was allowed in.

Europe can and should do better than this. The near-130

nuclear reactor units in operation across the EU provide

more than half of the bloc’s low-carbon electricity output.

According to the OECD’s Nuclear Energy Agency

(NEA), despite a 1.1 % decrease in total nuclear capacity

across NEA member countries in 2018 (292.7 GWe in

2018 compared to 296.0 GWe in 2017), the total

electricity production of these highly-efficient plants

increased.

Meanwhile, one of the planet’s oil-rich regions declared

itself the world’s latest nuclear energy newcomer with

the successful completion of fuel assembly loading at Unit

1 of the United Arab Emirates’ Barakah nuclear plant.

The UAE said on 3 March it was the first country in the

Arab world to achieve this status. CEO of the Emirates

Nuclear Energy Corporation, Mohamed Al Hammadi, said

the move was progress towards providing the UAE with

“clean, reliable and abundant electricity to power our

economic and societal growth”.

Oil exports account for around 25 % of the UAE’s gross

domestic product, so when such a region sees the economic

and environmental value of investing in nuclear power,

one might have thought that even the corridors of power in

Brussels would pay attention. Sadly not.

A reliance on facts seems to have little impact when it

comes to changing minds and policies on certain subjects

and nuclear often seems to fall victim to intransigence,

regardless of the evidence. Therefore, it’s important for

those who work inside and alongside the nuclear energy

community to build new alliances.

The president and CEO of the US Nuclear Energy

Industry, Maria Korsnick, hit the nail on the head recently.

She was discussing some of the misconceptions that

surround the industry when she said: “What we need is a

partnership between wind, solar and batteries, and a

carbon-free source like nuclear power that can always be

there. It’s really all of that working together.”

Cooperation between nuclear and battery storage does

of course hold promise. But I’ve even seen a nonsensical

approach to EU policymaking hamper progress in the

battery industry.

A couple of years ago, the Commission launched a

‘ Batteries Alliance’ to invest in research and development

of technologies to power future electric vehicles. All

well and good, I hear you say. Indeed, that would be

true, except for the fact that the initiative unashamedly

favored one chemistry (lithium-ion) over another (lead

batteries).

The then energy commissioner, Maroš Šefčovič, said

the EU would invest to support firms producing European

batteries with “truly green” credentials, which he regarded

as lithium rather than lead.

However, a study compiled for the Commission concluded

that the EU should first deal with its “outdated”

rules and inadequate targets for recycling lithium batteries.

By contrast, the study said the bloc’s lead battery firms

were helping to ensure near 100 % recycling of their

products under a highly-regulated process that was

“ generally profitable” and helped to reduce greenhouse

gas emissions!

Our politicians and policymakers have got to get out of

this bad habit of stacking the cards against a particular

technology for ideological reasons alone. There is no

one-size-fits-all solution to tackling climate change and

certainly no silver bullet.

Nuclear Today

Cards Still Stacked Against Nuclear in Green Investment Deal ı John Shepherd

Kommunikation und

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sowie an Juristen.

Referenten

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Dr. Christian Raetzke

ı Strahlenschutzexpertin bei der TÜV SÜD Energietechnik GmbH

Baden-Württemberg

ı Rechtsanwalt, Leipzig

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