atw - International Journal for Nuclear Power | 06/07.2019

atw Vol. 64 (2019) | Issue 6/7 ı June/July
Finally, in section 3.6 a sound overview on the position of
selected European countries is given.
3.1 Changed political framework in Germany
After the Fukushima nuclear disaster [GRS-16], the
German Federal government decided to terminate the
use of nuclear energy latest in 2022. The thirteenth
amendment of the Atomic Energy Act [ATG-11] came into
force on August 6, 2011. It regulates that the licenses of the
seven oldest and the Krümmel NPP expired and that the
remaining nine NPPs are to be shut down by 2022.
Consequently, the pressurized water reactor (PWR)
Grafenrheinfeld was shut down in 2015 and the boiling
water reactor (BWR) Gundremmingen Unit B in 2017
[BFE-18].
Worldwide, national government policies differ on the
further use of nuclear energy for electricity generation.
Many countries (e.g. China, Finland, France, Hungary,
Turkey, UK, USA, Russia) are planning to build new NPPs
or at least maintain and/or extend their operating time. In
Europe, currently 27 % of all electricity consumed in the
European Union (EU) is generated by NPPs. The projection
in the latest European Nuclear Illustrative Programme
(PINC) forecasts a stable nuclear capacity in Europe
between 95 and 105 GW e from 2030 onwards. At this time,
roughly 80 to 90 % of the installed capacity would be
new builds [EC-16].
Currently SMRs are discussed worldwide as one
interesting option for new builds in almost all countries,
which continue to use nuclear energy for commercial
power generation. For asserting of legitimate nuclear
safety and/or security interests, German authorities
­require in this context, own and independent expertise for
the safety assessments of NPPs and other nuclear facilities
in our neighborhood on an international level of the state
of the art in science and technology. This position, for
which a cross-party consensus exists, is e.g. stipulated in
the coalition agreement of the current Federal Government
[BR-18]. For this reason, the German Federal
Government continues to fund reactor safety research
which is in line with national and international framework
conditions and obligations.
The technical expertise in Germany for promoting
comprehensive safety reviews and ambitious binding
targets, is essentially built-up and provided by the
Gesellschaft für Anlagen- und Reaktorsicherheit (GRS)
gGmbH [GRS-19]. GRS is an independent non-profit
organization and entirely funded by projects. The main
shareholders are the Federal Republic of Germany and the
Technical Inspection Agencies, each with a share of
46.15 %. GRS is the
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main technical support organization (TSO) in nuclear
safety for the German Federal Government (especially
the Federal Ministry for the Environment, Nature
Conservation and Nuclear Safety (BMU) and the
­Federal Foreign Office (AA)),
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a major research organization in nuclear safety (e.g. for
the Federal Ministry for Economic Affairs and Energy
(BMWi), BMU and the Federal Ministry for Education
and Research (BMBF)) and
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traditionally involved in numerous international
activities (e.g. of the European Commission (EC), the
International Atomic Energy Agency (IAEA) and the
Nuclear Energy Agency of Organization for Economic
Co-operation and Development (OECD-NEA)).
As a first step, in this direction GRS performed a study on
Safety and International development of Small Modular
Reactors (SMR) [GRS-15], from which selected results are
presented in the following sections.
3.2 GRS study on safety and international
development of small modular reactors
The aims of the GRS study on Safety and International
Development of Small Modular Reactors [GRS-15],
published in 2015, were
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to set-up a sound overview on current SMR,
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to identify essential issues of SMR reactor safety
research and future R&D projects and
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to identify needs for adaption of system codes of GRS
used in this field of activity.
In the following, selected results (e.g. general trends and
safety features) are specifically described for the first
working point. For this it was advantageous to assign the
SMRs compiled in the Tables 1, 2 and 3 into groups.
Criteria for this were:
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the coolant (light-water, heavy-water, liquid metals,
gases and molten salts),
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the place of construction (onshore, offshore, subseabased)
and
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the state of deployment (in operation, construction,
­development with / without specific construction
intention).
3.3 Selected technical trends
In the following the selected trends of the SMRs are
summarized. Some of these trends apply for all SMRs
(­section 3.3.1 up to section 3.3.2), while others (section
3.3.3 up to section 3.3.5) are only valid for light-water
cooled SMRs. These SMRs have best chances of realization
in large numbers because they are based on a long-term
­operational proven technology and an already existing fuel
cycle. Furthermore, all nuclear stakeholder (especially of
the regulators) have collected the greatest experiences
with this technology by far.
3.3.1 Factory fabrication and transport
The definition SMR contains the two terms small and
modular. The term small characterises that SMR are small
(electrical output of less than 300 MW) in comparison to
currently operated NPP, which currently have an electrical
output of roughly 1000 to 1750 MW. Modular means
that these SMR have a modular construction and major
com ponents of a SMR are small enough to be built on a
production line in a factory and assembled on-site
[GAD-19]. Factory production allows to produce several
units simultaneously and not as present assembling one
item at a time [BAJ-18]. Standardisation increases quality
and reduces training [HUK-13].
The components of all current power reactors (for
­example in a PWR the reactor pressure vessel, the steam
generators, the main coolant pumps, the pressurizer and
the blow-off tank) are so large and heavy, so that these must
be manufactured, transported individually to the construction
site and connected here to each other by piping.
However, site construction has a higher risk of sub- standards
and/or rejects. The crafts are e.g. exposed to strongly
varying weather conditions, dirt and grime. Further more,
assembly and mounting devices are only available to a
­limited extend compared to a factory pro­duction [HUK-13].
On-site technical inspection is more ­difficult and is also
more expensive. The same is valid for the costs of on-site
production due to higher ancillary costs [SCA-19].
The advantage of SMR design with ship, truck or even
railway delivering in mind is that the size of modules
SERIAL | MAJOR TRENDS IN ENERGY POLICY AND NUCLEAR POWER 341
Serial | Major Trends in Energy Policy and Nuclear Power
SMRs – Overview on International Developments and Safety Features ı Andreas Schaffrath and Sebastian Buchholz