atw International Journal for Nuclear Power | 04.2020

nucmag.com
2020
4
ISSN · 1431-5254
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Nuclear Rockets
for Interplanetary
Space Missions
Excursus to the World
of Nuclear Medicine
Radiation in Art and
Cultural Heritage

Kommunikation und
Training für Kerntechnik
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Export kerntechnischer Produkte und Dienstleistungen –
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Atomrecht – Ihr Weg durch Genehmigungs- und
Aufsichtsverfahren
RA Kay Höft M.A. (BWL) 17.06.2020 Berlin
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Atomrecht – Was Sie wissen müssen
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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
p
specifically dedicated
to renewable hydrogen
production
600
400
396
451
510
200
0
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
0
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
G
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
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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

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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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| 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
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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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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).
Serial | Major Trends in Energy Policy and Nuclear Power
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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].
Serial | Major Trends in Energy Policy and Nuclear Power
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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
SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 201
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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 self- irradiation
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
Serial | Major Trends in Energy Policy and Nuclear Power
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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.
II
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.
3
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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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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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.
15
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.
16
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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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.
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Beeinträchtigung der Biosphäre führen
können (§ 2 Nr. 2, § 4 Abs. 3
VersV). 24
IV
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.
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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.
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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
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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
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Energy Policy, Economy and Law
Disposal of Dismantling Materials from Nuclear Facilities – A Legal Inventory ı Christian Raetzke

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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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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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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
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| 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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atw Vol. 65 (2020) | Issue 4 ı April
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
© Staatliche Museen zu Berlin – Gemäldegalerie, Inv. Nr. 486 (Jörg P. Anders).
| 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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| 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.
X-ray radiography (30 kV, 4 mAs, © TÜV NORD EnSys) of the painting from Fig.5, showing the older and
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.
The digital X-ray radiography (70 kV, 5 mAs, ©TÜV NORD EnSys) of a corroded tubule (above), found
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
2+
to cell membranes
or cell walls. Especially phosphate
groups are of importance for the
UO 2
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
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KTG-Fachgruppe Stilllegung und Entsorgung
Die KTG ist aktuell in sechs Fachgruppen untergliedert, in
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Die KTG-Fachgruppe Stilllegung und Entsorgung
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die sich aus der Planung und Durchführung von
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Anlagen sowie aus den Themengebieten Management und
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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
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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
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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)
1)
Refueling
2)
Inspection
3)
Repair
4)
Stretch-out-operation
5)
Stretch-in-operation
6)
Hereof traction supply
7)
Incl. steam supply
8)
New nominal
capacity since
January 2016
9)
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-$/
1995
Jan. 2014
2000
Jan. 2015
Jan. 2016
2005
Jan. 2017
) 1
2010
Jan. 2018
Jan. 2019
2015
Jan. 2020
2020
Year
* Actual nominal USD prices, not real prices referring to a base year. Year
Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020
* Actual nominal USD prices, not real prices referring to a base year. Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020
| Uranium spot market prices from 1980 to 2020 and from 2009 to 2020. The price range is shown.
In years with U.S. trade restrictions the unrestricted uranium spot market price is shown.
Separative work: Spot market price range [USD*/kg UTA]
Conversion: Spot conversion price range [USD*/kgU]
180.00
26.00
) 1 ) 1
160.00
140.00
120.00
100.00
80.00
60.00
40.00
20.00
0.00
Jan. 2021
Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020
Uranium prize range: Spot market [USD*/lb(US) U 3O 8]
140.00
) 1
120.00
100.00
80.00
60.00
40.00
20.00
0.00
24.00
22.00
20.00
18.00
16.00
14.00
12.00
10.00
Jan. 2009
8.00
6.00
4.00
2.00
0.00
Jan. 2009
Jan. 2010
Jan. 2010
kg U], Separative work [US-$/SWU
(Separative work unit)].
Jan. 2011
Jan. 2011
Jan. 2012
Jan. 2012
Jan. 2013
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
Jan. 2014
* Actual nominal USD prices, not real prices referring to a base year. Year
Jan. 2015
Jan. 2015
Jan. 2016
Jan. 2016
Jan. 2017
Jan. 2017
Jan. 2018
Jan. 2018
Jan. 2019
Jan. 2019
Jan. 2020
Jan. 2020
Jan. 2021
Sources: Energy Intelligence, Nukem; Bild/Figure: atw 2020
| Separative work and conversion market price ranges from 2009 to 2020. The price range is shown.
)1
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

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