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The presentation explains recent administrative developments in Germany concerning nuclear waste management and adresses national and European R&D funding concepts. National and international collaboration is explained followed by the latest update on long term metal seal investigations at BAM. Finally, fuel cladding failure mechanisms during long term dry storage and related R&D initiatives at BAM are explained.
This presentation addresses safety aspects concerning dual purpose casks for transportation and storage of spent fuel and high level radioactive waste. The long term performance of casks and their safety relevant components like sealed lid systems and the long term performance of cask internals, especially spent fuel assemblies are discussed. Transportation after interim storage is another key issue and due to the fact of delayed disposal projects current interim storage periods need to be extended causing additional safety demonstration needs for longer periods of time. Regarding this situation present BAM research activities in this area and their preliminary outcomes are presented.
The safe and secure long term storage of spent nuclear fuel until its final disposal in a deep geological repository is a corner stone of the German nuclear waste management strategy. So far interim storage licenses are limited to 40 years concerning the initial concept of having a repository available until 2035. But in the meantime the exploration of the designated Gorleben salt dome was finally stopped and a reset of the complete site selection process was concluded by the German Federal parliament and subsequently fixed by law. A 33-member “Commission on the storage of highly radioactive materials” was established in 2014, to elaborate a consent based siting process and to develop criteria for the safe disposal of heat generating waste. The disposal commission agreed and published its final report in 2016.
As a major consequence, the necessary timeframe for establishing the final repository is going to be exceeded significantly and with that, an extension of the current dry interim storage in dual purpose casks becomes necessary. This paper explains the major actions to be taken in Germany to address all relevant issues for a future extension of storage licenses beyond the initial timeframe of 40 years.
Suitable containers for receiving high-level radioactive waste are a key elements of every repository system concerning different host rocks like rock salt, claystone and crystalline rock as being considered in Germany. The disposal container design is decisive regarding boundary conditions for the transport, emplacement techniques, and the operational and long-term safety assessment. The systematic derivation of the requirements to be placed on disposal containers forms the basis for a targeted, comprehensible and transparent development of containers that meet the requirements. The presentation summarizes the outcomes of the research project KoBrA.
This presentation starts with a brief overview about the current situation of spent nuclear fuel and high level waste storage in Germany followed by a discussion of the expected timeline towards final disposal. Furthermore an overview is presented about research programmes for radioactive waste disposal and also extended interim storage issues due to the delay of the national repository siting procedure. In the second part of the presentation BAM research activities related to extended interim storage are addressed. This includes the status and preliminary results of proactive R&D projects concerning metal seals, degradation effects of polymers used as neutron shielding materials and finally elastomer seals.
This Presentation adresses the major needs and challenges of qualification processes for nuclear waste packages performed by BAM. Packages include those for high level radioactive waste like spent fuel as well as those for low and intermediate level waste to be disposed of in the Konrad repository.
Beginning with the current German nuclear waste management policy design testing capabilities and experience at BAM is explained followed by illustrating the major strategic process to identify future challenges including specific R&D needs.
The Bundesanstalt für Materialforschung und –prüfung (BAM) and Sandia National Laboratories (SNL) entered into a Memorandum of Understanding (MOU) in September 2012 to foster technical collaborations in the areas associated with the backend of the commercial nuclear fuel cycle. Specifically, the focus is on packaging, transportation, and storage of commercial spent nuclear fuel. The institutes meet about twice each year, alternating between institutes. This provides the opportunity for staff members from the host organization more exposure to technical issues that are of concern internationally and to collaborate with technical experts working on similar problems.
Since 2012, the focus of the meetings has been on technical issues associated with extended dry storage and subsequent transportation of commercial spent fuel. Topics range from hydride effects on cladding integrity, spent fuel response during Normal Conditions of Transport (NCT), finite element analyses of fuel and cask response to accident conditions, bolt and seal behavior over extended periods of time, and corrosion associated with bolts, metallic seals, and stainless steel canisters.
This MOU has provided an effective leverage for technical collaboration. For example, SNL is funding (through DOE), Savannah River National Laboratories (SRNL) to look at bolt and seal degradation issues. SRNL has an MOU with BAM to collaborate on bolt and seal degradation during extended storage. Likewise, Sandia and BAM are collaborating with the EC Joint Research Center on an International Nuclear Energy Research Initiative (I-NERI) to investigate spent fuel behavior when subjected to mechanical loadings. This important work will provide insight into failure mechanisms, as well as spent fuel release fractions, given a breach of the cladding wall.
This presentation provides an overview of high ranked technical issues associated with extended storage and subsequent transportation, as well as the work underway at BAM and SNL that are addressing these issues.
This presentation addresses the current German policy in nuclear waste management and illustrates significant changes throughout the last decades. With the reset of the high level waste repository siting process in 2013 the need for extending interim storage beyond initial license periods will become a future challenge. For that purpose knowledge needs to be enhanced and data gaps need to be closed timely. In addition, international collaboration in R&D and regulatory improvements are explained.
Integration across storage, transportation and disposal – important elements of the German program
(2016)
This presentation addresses the following issues. Unexpected changes in national nuclear policy have significantly affected spent fuel management strategies.
The initial German spent fuel and HLW disposal concept has been delayed and finally “reset” by federal law in 2013. Repository site selection criteria and procedures will be defined by the Disposal Commission’s report end of June 2016. Final site selection should be finished by 2031.
The consistent German concept of dry interim storage in dual purpose casks has proven to be a safe and secure spent fuel management strategy.
The need for the extended interim storage of spent fuel and HLW casks towards disposal implicates additional challenges for the nuclear waste management strategy in Germany.
Recently, governmental research programs have been adjusted to address technical and scientific issues also in the predisposal area.
Interim storage, subsequent transportation, and final disposal are closely linked. Integrated approaches concerning waste package designs and operations are supposed to be beneficial for the establishment of efficient long-term spent fuel and HLW management strategies.
The presentation focuses on the latest developments of the German nuclear waste management policy including restructering of responsible organizations and the restart of the repository site selection process for high level radioactive waste.
The second part illustrates latest results of long term investigations of metal seals at BAM with regard to extended interim storage periods.
Ongoing R&D work at BAM
(2018)
The presentation provides an update on the German nuclear waste management policy towards final disposal and related reasearch at BAM. Topics include long term investigations of metal seals, investigations of fuel cladding failure mechanisms, and the development of requirements and concepts for high level radioactive waste and spent fuel disposal containers.
Perspectives on extending interim storage of spent nuclear fuel (beyond the initial license period)
(2017)
The presentation adddresses the consequences and challenges of the German nuclear phase-out in conjunction with the restart of siting process for a high-level radioactive waste repository. Concerning spent fuel this will lead to extended interim storage periods for the dry storage casks beyond the initial licensing period of 40 years.
For extending storage periods additional safety assessments and data about the long term performance of materials, components and casks will be needed and BAM has already been lauching specific R&D projects addressing identified data gaps.
This paper describes and discusses the major challenges of spent fuel management in Germany after the phase-out of nuclear electricity generation was decided in 2011 and a new repository siting procedure was implemented in 2013. Consequences from those decisions which were legally founded by amendments of the German Atomic Energy Act (AtG) result in the need to transfer all remaining spent fuel from limited reactor operation (last reactor shutdown until the end of 2022) into casks for subsequent dry interim storage on-site. Storage licenses are generally issued site-specific considering specific dual purpose casks (DPC) and their inventories and they are generally limited to 40 years so far. But the need for extending the interim storage period in the future has become obvious. Even though, this may not be an issue to be solved already today questions about additional safety demonstrations will arise as soon as licenses need to be extended. Certainly, these questions will ask for reliable data about the long term performance and safety of structures, systems, and components, e. g. the long term performance of cask components and materials like bolted closure systems including metal seals, or fuel rod behaviour concerning cladding materials under stress and temperature conditions. In case of dual purpose casks for storage and transportation this includes aspects on how to demonstrate transportability during or after several decades of interim storage. Long term investigations often require plenty of time and therefore need to be initiated timely.