TY - JOUR A1 - Droste, Bernhard A1 - Völzke, Holger A1 - Wieser, Günter A1 - Qiao, Linan T1 - Safety Margins of Spent Fuel Transport and Storage Casks Considering Aircraft Crash Impacts PY - 2002 SN - 0957-476X VL - 13 IS - 3-4 SP - 313 EP - 316 PB - Nuclear Technology Publ. CY - Ashford, Kent AN - OPUS4-2697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Lange, F. A1 - Hörmann, E. A1 - Schwarz, G. A1 - Droste, Bernhard A1 - Völzke, Holger A1 - Wieser, Günter T1 - Spent Fuel Transport and Storage Casks under Extreme Accidents T2 - 10th International High-Level Radioactive Waste Management Conference (IHLRWM-10) CY - Las Vegas, NV, USA DA - 2003-03-30 PY - 2003 SN - 0-89448-669-1 SP - 465 EP - 470 PB - American Nuclear Society CY - La Grange Park, Ill. AN - OPUS4-2698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Droste, Bernhard A1 - Zencker, Uwe T1 - Safety Assessment Aspects of Materials for Radioactive Waste Containers T2 - 4th International Seminar on Radioactive Waste Products CY - Würzburg, Germany DA - 2002-09-22 PY - 2002 AN - OPUS4-5742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe A1 - Qiao, Linan A1 - Kasparek, Eva Maria A1 - Völzke, Holger T1 - Modeling of cylindrical casks under horizontal drop test conditions N2 - Cylindrical casks made of ductile cast iron are used for transport, interim storage and final disposal of radioactive waste in Germany. A basic design criterion is the ability to withstand a horizontal drop without impact Binders onto a foundation representative for the real ground of a storage facility. The increasing use of more cost-effective material compositions requires optimized cask geometries to reduce stresses and strains in the cask structure. For example, a non-uniform wall thickness was introduced to reduce maximum wall bending stresses. As a result, the load characteristics changed from line load to point load at bottom and lid side under horizontal drop fest conditions. Hereby, the position of highest stress inside the structure has shifted significantly. This was the reason for a systematic investigation of effects caused by small design changes or small variations of fest conditions. It led to a better understanding of the positions of high local stresses, their time history and maximum value for cylindrical casks under horizontal drop test conditions. Hence, the paper presents the lessons learnt from modeling and simulating such scenarios considering an impact without limiters onto a realistic target. T2 - 14th International high-level radioactive waste management conference CY - Albuquerque, New Mexico, USA DA - 28.04.2013 KW - Cylindrical cask KW - Ductile cast iron KW - Numerical simulation KW - Horizontal drop test KW - Storage facility KW - Concrete foundation PY - 2013 SN - 978-1-62748-644-6 SP - 1114 EP - 1119 (Paper # 6862) PB - Omnipress AN - OPUS4-28529 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Extended storage collaboration program international subcommittee report: International perspectives on technical data gaps associated with extended storage and transportation of used nuclear fuel PY - 2012 VL - 1026481 IS - Chapter 2.1, 3.1, 4.1 SP - 2-1 - 2-5, 3-1 - 3-4, 4-1 - 4-3 CY - Palo Alto, CA, USA ET - Final report AN - OPUS4-27405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eisenacher, Germar A1 - Scheidemann, Robert A1 - Neumann, Martin A1 - Droste, Bernhard A1 - Völzke, Holger T1 - Dynamic crushing characteristics of spruce wood under large deformations N2 - An extensive series of large deformation crushing tests with spruce wood specimens was conducted. Material orientation, lateral constraint and loading rate were varied. Regarding material orientation, a reduction in the softening effect and the general force level was observed with a higher fiber-load angle. A comparison with characteristics gained by application of Hankinson's formula showed discrepancies in compression strength and the beginning of the hardening effect. Lateral constraint of the specimens caused a multiaxial stress state in the specimens, which was quantified with the applied measuring method. Further, a higher force level compared to specimens without lateral constraint and significant hardening effect at large deformations resulted. Thus, the influence of a multiaxial stress state on the force level could be determined. An increase in the loading rate led to higher force levels at any displacement value and material orientation. KW - Crushing test KW - Dynamic crushing characteristics KW - Spruce wood KW - Lateral constraint KW - Multiaxial stress state KW - Hankinson's formula PY - 2013 DO - https://doi.org/10.1007/s00226-012-0508-5 SN - 0043-7719 SN - 1432-5225 VL - 47 IS - 2 SP - 369 EP - 380 PB - Springer CY - Berlin AN - OPUS4-27743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Qiao, Linan A1 - Zencker, Uwe A1 - Wieser, Günter A1 - Völzke, Holger ED - Topping, B. H. V. ED - M. Papadrakakis, T1 - Numerical safety assessment of a transport and storage cask for radioactive materials without impact limiters by the 0.3m drop test onto an unyielding target T2 - 9th International Conference on Computational Structures Technology (CST2008) CY - Athens, Greece DA - 2008-09-02 KW - Impact KW - Simulation KW - Cask KW - Safety KW - Drop KW - Foundation KW - Unyielding KW - Target PY - 2008 SN - 978-1-905088-23-2 IS - Paper 21 SP - 1 EP - 10 PB - Civil Comp Press CY - Kippen AN - OPUS4-18340 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Zencker, Uwe A1 - Qiao, Linan A1 - Feutlinske, Karl A1 - Musolff, André T1 - Drop tests and numerical impact analyses of new cask designs for high activity waste (HAW) and spent fuel - updated BAM design testing experiences - T2 - Waste Management Conference 2007 CY - Tucson, AZ, USA DA - 2007-02-25 PY - 2007 AN - OPUS4-14577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erhard, Anton A1 - Völzke, Holger A1 - Noack, Volker A1 - Weber, Wolfgang A1 - Wolff, Dietmar A1 - Rittscher, D. A1 - Schmidt, H. T1 - Long term interim storage facility for nuclear reactor compartments of submarines - German support for utilization of nuclear submarines in Russia T2 - PATRAM 2007, 15th International Symposium on the Packaging and Transportation of Radioactive Materials CY - Miami, Florida, USA DA - 2007-10-21 PY - 2007 SP - 155 PB - Institute of Nuclear Materials Management AN - OPUS4-16157 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sterthaus, Jens A1 - Ballheimer, Viktor A1 - Droste, Bernhard A1 - Koch, Frank A1 - Probst, Ulrich A1 - Völzke, Holger A1 - Wille, Frank T1 - Analysis of bolted flange joints for lids of packages for radioactive materials T2 - ASME 2009 Pressure vessels and piping conference CY - Prague, Czech Republic DA - 2009-07-26 KW - Bolted flange joints KW - FEA KW - Modelling of gaskets KW - Assessment of leak tightness KW - Results from experiments PY - 2009 SP - PVP2009-77284, 1-8 PB - American Society of Mechanical Engineers CY - New York AN - OPUS4-19786 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völzke, Holger A1 - Wieser, Günter A1 - Zencker, Uwe A1 - Droste, Bernhard T1 - Mechanical and thermal safety analyses and demonstrations for cubic DCI multipurpose containers PY - 1997 SN - 0957-476X VL - 8 IS - 3-4 SP - 247 EP - 252 PB - Nuclear Technology Publ. CY - Ashford, Kent AN - OPUS4-21664 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erhard, Anton A1 - Völzke, Holger A1 - Droste, Bernhard A1 - Wolff, Dietmar A1 - Wille, Frank T1 - Nuclear power plant waste management strategy in Germany T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 2013-08-18 PY - 2013 SP - 1 EP - 11(?) PB - Omnipress AN - OPUS4-30135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Wille, Frank A1 - Droste, Bernhard T1 - Extended storage after long-term storage N2 - Existing spent nuclear fuel (SF) and high active waste (HAW) management policies and practices worldwide are the result of past presumptions that sufficient reprocessing and/or disposal capacity would be available in the near term. Consequently, in the past many countries have developed specific solutions for different periods of time due to their individual national nuclear policies. In Germany the concept of dry interim storage in dual purpose metal casks before disposal is being pursued for SF and HAW management and transport and storage licenses have been issued accordingly. The current operation licenses for existing storage facilities have been granted for a storage period of up to 40 years. This concept has demonstrated its suitability for over 20 years so far. Relevant safety requirements haven been assessed for the short-term as well as for the long-term for site-specific operational and accidental storage conditions. But in the meantime significant delays in the national repository siting procedure occured which will make extended storage periods necessary in the future. This paper describes the current situation in Germany with regard to dry cask storage and focuses on current perspectives considering regulatory, technical, and scientific aspects for storage license renewal. Since there is one case of a storage license limitation to only 20 years due to administrative reasons, first experience is currently gathered in case of an expiring storage license. Subsequent license options have been pursued intensively including the extension of the initial storage license as well as shipping all casks to another storage facility considering an extended storage period at that storage facility as well. All safety relevant aspects have to be reviewed on basis of the current state-of-the-art which might be different from the initial safety demonstrations. That includes new safety assessment standards as well as improved knowledge base. Major issues are e.g. improved accident scenario analyses, assessment methods, and consideration of aging effects from previous operation periods. Inspection programs with respect, e.g. to bolts and seals to verify leak-tightness and lid screw pre-stress have been initiated to demonstrate proper cask conditions for extended storage as well as transportation to another storage facility. T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 18.08.2013 KW - Extended storage KW - Long-term storage KW - Dual purpose cask PY - 2013 SP - Paper 184, 1 EP - 12 PB - Omnipress AN - OPUS4-30242 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Erhard, Anton A1 - Völzke, Holger A1 - Probst, Ulrich A1 - Wolff, Dietmar T1 - Ageing management for long term interim storage casks T2 - PATRAM 2010 - 16th International symposium on the packaging and transport of radioactive materials CY - London, UK DA - 2010-10-03 KW - Ageing management KW - Lifetime KW - Material degradation PY - 2010 SP - 1 EP - 17 (Tuesday/T20/61) AN - OPUS4-23907 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Nieslony, Gregor A1 - Noack, Volker A1 - Hagenow, Peter A1 - Kovacs, Oliver T1 - Current developments in container design testing for the Konrad repository N2 - The Konrad repository for not heat generating radioactive wastes was licensed first in 2002. But due to legal actions this license has not been finally confirmed before 2007. Subsequently, the Federal Office for Radiation Protection (BfS) began scheduling backfitting of the former iron ore mine into a repository. The licensed repository volume is 303,000 m3 based on estimations of expected waste volumes to be disposed off although the mine itself would offer a much larger volume. Once the repository is ready for Operation, waste packages can be disposed, but this is not expected before the end of this decade. Nevertheless, there is already today a great interest in qualified and certified waste conditioning and packaging for disposal requiring Containers, tested, evaluated and certified by BAM and BfS. Key points of the Konrad license concern comprehensive requirements for waste products and Containers. Details are described in BfS reports, which constitute the basic documents for the license. Following the final license confirmation a revision of these documents has been requested in order to include considerations of water poisoning substances. This work is currently done by BfS in Cooperation with the NLWKN of Lower Saxony and the Institute for Safety Technology (ISTec). Concerning the specification for Containers themselves no or only minor changes are expected. T2 - KONTEC 2011 - 10. Internationales Symposium "Konditionierung radioaktiver Betriebs- und Stilllegungsabfälle" CY - Dresden, Deutschland DA - 06.04.2011 KW - Cask KW - Safety KW - Repository KW - Design testing KW - Radioactive waste PY - 2011 SP - 683 EP - 695 AN - OPUS4-23672 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Völzke, Holger A1 - Rödel, Roland A1 - Zeisler, Peter A1 - Droste, Bernhard T1 - Considerations of the competent authority concerning the assessment of a brittle fracture safe ductile cast iron (DCI) cask design PY - 1995 SN - 0957-476X VL - 6 IS - 2/3 SP - 121 EP - 126 PB - Nuclear Technology Publ. CY - Ashford, Kent AN - OPUS4-21731 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Droste, Bernhard A1 - Zeisler, Peter A1 - Völzke, Holger A1 - Rödel, Roland T1 - Development and evaluation of containers for radioactive waste disposal PY - 1994 SN - 0957-476X VL - 5 IS - 1 SP - 27 EP - 32 PB - Nuclear Technology Publ. CY - Ashford, Kent AN - OPUS4-21735 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nagelschmidt, Sven A1 - Probst, Ulrich A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Long-term investigations of metal seals for storage casks of radioctive materials N2 - The Bundesanstalt für Materialforschung und –prüfung (BAM) is a federal institute for materials research and testing in Germany and has been involved in the qualification and safety evaluation procedures of metal seals from the early beginning of the interim storage licensing procedures for radioactive materials, stored in dual purpose casks. Regarding this subject, BAM investigates the long-term behavior of metal seals under the influence of temperature using experimental data and analytical approaches. The development of numerical models is in progress as well. Systematic experimental investigations performed by BAM indicate a continuous decrease of the remaining seal force and the usable resilience considering the leak tightness. Hence, there is a fundamental interest of describing time and temperature dependency to gain predictable values for the long-term behavior and to achieve reliable results with help of short-term tests. The paper gives an overview about the sealing principle, test program and test results of metal seals of the type HELICOFLEX® HN200. The aging effect, respectively the long-term behavior in dependency of time and temperature, are introduced for two different outer liner materials, aluminum and silver. T2 - PVP ASME Conference CY - Vancouver, Canada DA - 17.07.2016 KW - Long-Term Behaviour KW - Metal Seal KW - Metal Gasket PY - 2016 SN - 978-0-7918-5045-9 VL - 7 SP - 63596-1 EP - 63596-5 AN - OPUS4-38039 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Liu, Y. T1 - Collaboration on aging management for extended storage of used fuel N2 - A Memorandum of Understanding (MOU) between the Federal Institute for Materials Research and Testing (BAM) and Argonne National Laboratory (Argonne) was signed in the fall of 2014. Its objectives are to promote cooperation among scientists and specialists at BAM and Argonne and establish a framework for collaboration in the field of advanced technologies associated with the back end of the nuclear fuel cycle. Collaborative activities involving the BAM and Argonne may be implemented through the promotion of joint research activities and scientific workshops and conferences; the exchange of technical information; and visits by scientists, specialists, and graduate, postgraduate, and Ph.D. students. The first Argonne/BAM workshop was held at Argonne in October 2014 to discuss aging management issues related to the long-term dry storage of spent fuel. Major topics for potential collaboration on the extended storage of spent nuclear fuel and its subsequent transportation were identified. T2 - IHLRWM 2015 - 15th International high-level radioactive waste management conference CY - Charleston, SC, USA DA - 12.04.2015 KW - Aging management KW - Fuel KW - Extended storage KW - Nuclear PY - 2015 SN - 978-0-89448-719-4 SP - 814 EP - 817 AN - OPUS4-33115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kasparek, Eva Maria A1 - Völzke, Holger T1 - Further research on cask impact limiter needed? N2 - Transport and storage casks for medium and high level radioactive waste are subjected to extreme heavy loads during the accidental drop scenarios prescribed by IAEA regulations and national storage acceptance criteria. Subsequently, considerable efforts have been made to optimize impact limiting structures aiming to reduce cask stresses and deformations. Though, their benefits can only fully be exploited, if the energy absorbing behavior is reliable simulated by numerical models which play an increasingly important role in safety assessments. BAM has had conducted the 5-years research project ENREA in order to overcome the problems caused by the use of simplified, not sufficiently validated or even defective computational concepts for damping materials. While major results of the just recently completed program will be presented, the focus is laid on the question whether these Outputs provide a solid foundation for approximating impact limiting structures in all relevant configurations. So far, material models have been implemented for spruce, Polyurethane foams and damping concrete based mainly on small and medium scale compression test results. The experimental program performed at BAM comprised likewise guided drop tests and, especially for concrete, penetration tests. Although the resulting numerical simulations showed good agreement with measured values, it turned out to be necessary to consider further effects with regard to e.g. multiaxial stress States, shearfailures of shock absorbing components and their interaction with enclosed or enclosing structures. Thus, the strengths and application constraints of the actual models will be shown as well as details about further research needs, if any. T2 - RAMTRANSPORT 2015 - International conference on the radioactive materials transport and storage CY - Oxford, UK DA - 19.05.2015 KW - Numerical model KW - Shock absorber KW - Damping concrete KW - Polyurethane foam KW - Radioactive waste storage cask PY - 2015 SP - 1 EP - 8 AN - OPUS4-33992 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wille, Frank A1 - Wolff, Dietmar A1 - Droste, Bernhard A1 - Völzke, Holger A1 - Baden, M. T1 - German approach and feedback on experience of transportability of SNF packages after interim storage N2 - In Germany, the concept of dry interim storage of spent fuel in dual purpose metal casks is implemented, currently for periods of up to 40 years. The casks being used have an approved package design in accordance with the international transport regulations. The license for dry storage is granted on the German Atomic Energy Act with respect to the recently revised 'Guidelines for dry interim storage of irradiated fuel assemblies and heat-generating radioactive waste in casks' by the German Waste management Commission. For transport on public routes between or after long term interim storage periods, it has to be ensured that the transport and storage casks fulfil the specifications of the transport approval or other sufficient properties, which satisfy the proofs for the compliance of the safety objectives at that time. In recent years, the validation period of transport approval certificates for manufactured, loaded and stored packages were discussed among authorities and applicants. A case dependent system of 3, 5 and 10 years was established. There are consequences for the safety cases in the Package Design Safety Report, including evaluation of long term behaviour of components and specific operating procedures of the package. The present research and knowledge concerning the long term behaviour of transport and storage cask components have to be consulted as well as experiences from interim cask storage operations. Challenges in the safety assessment are e.g. the behaviour of aged metal and elastomeric gaskets under IAEA test conditions to ensure that the results of drop tests can be transferred to the compliance of the safety objectives at the time of transport after the interim storage period. Assessment methods for the material compatibility, the behaviour of fuel assemblies and the aging behaviour of shielding parts are issues as well. This paper describes the state of the art technology in Germany, explains recent experience on transport preparation after interim storage and points out arising prospective challenges. KW - Radioactive material storage KW - Dry storage KW - Interim storage KW - Cask design KW - Radioactive material transport KW - Regulation KW - Operating procedures KW - Package KW - Safety KW - Storage KW - Transport KW - Lagerung KW - Spent fuel PY - 2014 DO - https://doi.org/10.1179/1746510914Y.0000000064 SN - 1746-5095 SN - 1746-5109 SN - 0957-476X VL - 25 IS - 2 SP - 55 EP - 59 PB - Ramtrans Publ. CY - Ashford AN - OPUS4-33834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kasparek, Eva A1 - Völzke, Holger T1 - Non-Heat Generating Legacy Waste - New Strategies for Older Vessels N2 - The German repository “Konrad” is approved for the final storage of approximately 300.000 m³ of non-heat generating radioactive waste considering also the expected residues from operation and decommissioning of current power plants. According to the latest survey as constituted end of 2014, a large proportion of this volume already exists, of which 100.288 m³ are fully loaded packages. As prerequisite for their “Konrad” acceptance, the vessels have to be designed against operational and accidental conditions of the site and be manufactured according to adequate quality assurance programs. The respective safety assessment performed by BAM on behalf of the Federal Office for Radiation Protection is a major challenge especially for those casks that had been produced and loaded already some decades ago. Typically, they were manufactured in big numbers over a longer period of time involving a lot of constructional and management changes. This fact in combination with the previously rather low documentation standards often causes relevant uncertainties about the specific physical and geometrical characteristics of the cask materials and components as well as about details concerning their whole assemblage. This paper highlights current assessment strategies for such older vessels including cubic steel sheet containers as well as cylindrical thick-walled casks. As compliance with each “Konrad”-requirement can hardly be shown independently, only integrated approaches promises success: First, a broader concept of data collection has to be implemented that allows closing documentation gaps by linking dispersed and diverse data, e.g. delivery slips and handwritten fabrication records, by including plausibility considerations as well as random inspection programs. Thereby, the relevant properties of all applied casks have to be identified and their potential range should be quantified as accurately as possible. This knowledge is necessary to define one or more representative configurations of the cask as the base for design testing. The actual investigation program must enable to track the influence of deviations and determine safety margins especially in the likely case that not the most conservative setting of all cask features can be tested. The paper evaluates the respective ongoing efforts of industrial applicants and summarizes BAM experiences and associated research projects. T2 - 18th International Symposium on the Packaging and Transportation of Radioactive Materials CY - Kobe, Japan DA - 18.09.2016 KW - Requalification KW - Low and medium level radioactive waste KW - Final disposal container KW - Legacy waste KW - Konrad repository PY - 2016 SP - Paper 1014, 1 EP - 9 AN - OPUS4-38892 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Orellana Pérez, Teresa T1 - Latest developments in Germany concerning extended interim storage N2 - 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. T2 - EPRI Extended Storage Collaboration Program (ESCP) International Subcommittee Meeting CY - Jeju, Korea DA - 15.09.2017 KW - Nuclear waste management KW - Long term storage KW - Spent fuel PY - 2017 AN - OPUS4-43793 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Orellana Pérez, Teresa A1 - Völzke, Holger A1 - Wolff, Dietmar A1 - Zencker, Uwe T1 - Relevance of cladding failure mechanisms due to zirconium hydride precipitation under extended dry storage conditions in Germany N2 - The German nuclear waste management strategy consists of dry interim storage of spent fuel inside dual purpose casks and its subsequent direct final disposal in a deep geological repository. Interim storage is limited to 40 years so far, but will have to be extended until repository site selection and operation is concluded, potentially up to 100 years. In this context, research on the long term performance of safety relevant cask components and fuel rod integrity during such extended periods of time is of outmost importance. The barrier function of the fuel cladding depends on its integrity under operational and accidental conditions along with storage and subsequent transportation and is mainly affected over time by altering of the cladding microstructure and by thermo-mechanical conditions during reactor operation and subsequent wet and dry storage. This paper focuses on failure mechanisms regarding cladding embrittlement caused by physical phenomena concerning hydrogen dissolution and precipitation of hydrides in the zirconium matrix. Within this context, potential cladding integrity issues under extended interim storage conditions followed by transportation are emphasized. Delayed hydride cracking (DHC) is a well-known time-dependent temperature-activated phenomenon failure mechanism of the fuel cladding during reactor operation. The phenomenon consists of hydrogen diffusion and hydride precipitation at the tip of an initial crack and the propagation of the crack to an approximate distance equal to the length of the hydride. This failure mechanism is temperature-activated phenomenon and enhances along with thermal cycling of the fuel cladding, e. g. during reactor shutdowns. DHC shows limited relevance under quasi static storage conditions with continuously lowering temperatures. However, the literature points that DHC may occur when the temperature during storage decreases to a certain level after some decades and in combination with stress concentrations in the cladding material. When spent fuel is transferred to dry storage by vacuum drying, the cladding temperature raises up to peak temperatures of ~370°C. Under these conditions, hydrides dissolute into the zirconium matrix up to the solubility limit defined by the peak temperature and this amount of hydrogen can precipitate in a radial re-oriented fashion due to the temperature decrease during storage. Cladding materials with radially precipitated hydrides show significant embrittlement. Radially oriented hydrides are perpendicularly oriented to hoop stresses representing the most critical configuration. Brittle failure of the cladding then occurs by crack propagation through radially oriented hydrides and finally through the zirconium matrix. The susceptibility to radial hydride precipitation depends on cladding material type and microstructure, hydrogen content, pre-drying hydride distribution, irradiation conditions, and temperature and stress histories during drying and storage operations. This paper addresses major considerations concerning spent fuel cladding embrittlement due to hydride precipitation with regard to the boundary conditions of dry spent fuel storage in Germany. Analytical, numerical, and experimental approaches are to be discussed by BAM in order to identify the specific needs for future R&D work in that area with the purpose to provide the necessary data base for proper safety demonstration and evaluation along with future extended storage licensing procedures. T2 - 2017 Water Reactor Fuel Performance Meeting CY - Jeju, Korea DA - 10.09.2017 KW - Cladding KW - Hydride precipitation KW - Spent fuel PY - 2017 SP - 1 EP - 8 AN - OPUS4-44749 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger T1 - Safety demonstrations with regard to extended interim storage N2 - 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. T2 - 5. RAM-Behältersicherheitstage CY - Berlin DA - 16.03.2016 KW - Interim storage KW - Radioactive waste KW - Spent fuel KW - Safety PY - 2016 AN - OPUS4-35615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Update on the German approach of storing spent nuclear fuel in dual purpose casks until final disposal N2 - The German approach of storing spent nuclear fuel in dual purpose casks until final disposal is based on individually licensed storage sites concerning specific nuclear inventories and dual purpose cask types. The currently approved license period is maximum 40 years. With nuclear policy changes including the phase-out decision of 2011 and a new approach for the HLW repository siting process set up 2013 by law also the spent fuel and HLW management strategy has to be adapted. This includes the timely development of disposal container concepts as part of the overall repository siting process and the need for longer interim storage periods until final disposal. Other aspects affect new regulations about the financing of the nuclear waste management by the industry and the public sector, the restructuring of responsible authorities in 2016/2017 and the adaption of R&D funding programs addressing also pre-disposal (or extended interim storage) issues. BAM as a Federal Research Institute has been responsible for or in charge of container safety Evaluation for transport and storage casks for radioactive waste for several decades and started addressing potential Extended interim storage issues already several years ago. This included participation in international projects at the IAEA or in the U.S. Extended Storage Collaboration Program (ESCP) as well as long term laboratory tests with metal seals, elastomeric seals and polymers for neutron shielding purposes. Test results of BAM are published regularly and gained data provide valuable information about thermo-mechanical and radiological degradation effects as well as the long term Performance of respective cask components. Regarding the reliable extrapolation and prediction of the long term Performance of cask materials and components for time periods of up to 80 or even 100 years the continuation and extension of laboratory tests and the development of analytical and numerical simulation models and tools is essential and under way. T2 - 16th International High -Level Radioactive Waste Management Conference (IHLRWM 2017) CY - Charlotte, NC, USA DA - 09.04.2017 KW - Spent fuel KW - Storage KW - Cask KW - Safety KW - Disposal PY - 2017 SP - 189 EP - 194 AN - OPUS4-40411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Investigation of the time and temperature dependent behavior of metal seals in radioactive waste containers N2 - The Bundesanstalt für Materialforschung und –Prüfung (BAM) runs an investigation program on the long-term behavior of multi-component metal seals. Such seals are used in a wide area of applications including transport and storage casks for spent nuclear fuel and high level radioactive waste. The seal function is mainly based on the compression of the inner helical spring, which generates the necessary seal force to keep the sealing surfaces in close contact. This in turn leads to a plastic deformation of the outer jacket of the seal, comprised of highly ductile aluminum or silver that adapts to the sealing surfaces of cask body and bolted lid, thus providing high Level leak tightness. In Germany, those casks are licensed for Interim storage periods of up to 40 years or more if extended Interim storage would become necessary before a final repository is available. Thus, the sealing performance has to be evaluated, including factors like elevated temperature due to decay heat or mechanical loads due to transport under normal as well as accident conditions. Long-term investigations at BAM have been running over the last nine years to identify and evaluate the seal performance by measuring the remaining seal force, the useable resilience and the leakage rate after various time intervals at temperatures ranging from room temperature up to 150 °C. It was found that the seal force and useable resilience decrease with time and temperature, caused by creep deformation of the outer jacket. In order to obtain an analytical description for the seal behavior and to achieve more information on the material behavior under application conditions a comprehensive investigation program with Focus on aluminum as outer jacket material was launched. The program includes material investigations such as compression and tension creep tests with representative basic materials. An additional test setup allows for the continuous measurement of the remaining seal force at temperatures of up to 150 °C. Furthermore, seal segments are compressed and stored in heating chambers, thus producing segments at different stages of the aging process. The segments are investigated regarding the development of the contact area width, jacket thickness and microstructural changes. This data will be used to develop material models and an analytical description of the time and temperature dependent long-term sealing behavior. This paper explains the current status of gained test results and modelling approaches and closes with an outlook to the future Project plans. T2 - ASME 2018 Pressure Vessels and Piping Conference CY - Prague, Czech Republic DA - 15.07.2018 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2018 SP - PVP2018-84584, 1 EP - 6 AN - OPUS4-46110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheidemann, Robert A1 - Weber, Mike A1 - Völzke, Holger A1 - Kasparek, Eva Maria ED - Gomes, J.F.Silva ED - Meguid, S.A. T1 - Temperature dependendency of dynamically loaded polyurethane foam N2 - Polyurethane foam used as impact limiter material undergoes high plastic deformations, whereat the resulting stress-strain relations strongly depend on loading speed and temperature. This paper discusses the efforts necessary to develop a reliable numerical foam simulation model focussing on generation and implementation of temperature- dependent yield curves T2 - 6th International Conference on Mechanics and Materials in Design CY - Ponta Delgada, Azores, Portugal DA - 26.07.2015 KW - Impact limiter KW - Polyurethane foam KW - Finite element model KW - Strain rate KW - Temperature dependency PY - 2015 SN - 978-989-98832-3-9 SP - 1043 EP - 1046 PB - INEGI-FEUP AN - OPUS4-38889 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Völzke, Holger A1 - Droste, Bernhard A1 - Rödel, Roland T1 - Safety aspects of long-term dry interim storage of type-B spent fuel and HLW transport casks KW - Transport casks KW - Interim storage KW - Leak tightness KW - KOBAF PY - 2004 SN - 1746-5095 SN - 1746-5109 SN - 0957-476X VL - 15 IS - 3-4 SP - 207 EP - 213 PB - Ramtrans Publ. CY - Ashford AN - OPUS4-7414 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shirai, K. A1 - Namba, K. A1 - Wataru, M. A1 - Völzke, Holger A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Schulz, Sebastian T1 - Numerical evaluation of the long-term sealing performance of the silver gasket for dual purpose metal cask under high temperature N2 - It is important to evaluate the effect of thermal ageing on the sealing performance of metal gaskets under high temperature for long-term usage. Therefore, in order to gain representative data for this kind of metal-sealed lid System, BAM is currently performing laboratory tests of different gasket types with aluminum and silver jackets at three different temperatures under static conditions up to four years so far, using test flanges for gaskets with full scale cross section diameter but much smaller outer diameter. On the other hand, in order to investigate the applicability of the numerical methodology to evaluate the long-term behavior of the metal gaskets, such as a correlation between seal pressure force and holding time, CRIEPI is developing a modeling method including material tests (tensile and creep tests) at high temperature. In this paper, the applicability of the finite element method (ABAQUS) to predict the recovery displacement and residual seal pressure force of the gasket complex was verified by comparing the calculated values with BAM’s laboratory test results under the joint research agreement between BAM and CRIEPI. T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 18.08.2013 KW - Metal seals KW - Extended storage KW - Long-term storage KW - Dual purpose cask PY - 2013 SP - 1 EP - 8 PB - Omnipress AN - OPUS4-31947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Jaunich, Matthias A1 - Zencker, Uwe A1 - Simbruner, Kai A1 - Nagelschmidt, Sven A1 - Herbrich, Uwe A1 - Keller, Christian A1 - Qiao, Linan T1 - Research at BAM on Metal Seal Performance and Fuel Rod Integrity N2 - The presentation provides an update on preliminary results from research projects in the area of long term performance of metal seals and fuel rod integrity as safety relevant components of spent fuel transport and storage casks for spent nuclear fuel. T2 - Extended Storage Collaboration Program (ESCP) Winter Meeting 2020 CY - Online meeting DA - 09.11.2020 KW - Metal seal KW - Safety KW - Interim storage KW - Spent nuclear fuel KW - Fuel rod PY - 2020 AN - OPUS4-51615 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kasparek, Eva Maria A1 - Scheidemann, Robert A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Völzke, Holger T1 - Effect of dynamic loading on compressional behavior of damping concrete N2 - In drop test scenarios related to assessing and licensing the storage procedure of spent fuel and high active waste, the casks under examination are generally not equipped with impact limiters. Hence, the extent of mechanical stresses in case of an assumed handling accident is largely affected by the ground properties of the reception hall floor in the specific storage facility. Unlike conventional brittle foundation materials, damping concrete performs quite well in such applications as it features high stiffness as well as high energy absorption due to the filler pore volume. However, its damping ability is not sufficiently exploited in current finite element (FE) calculations due to a lack of advanced material models for simulating its impact response. An implementation of qualified concepts that account for plastic, strain rate dependent behavior requires additional information that has to be provided by systematic test series. BAM recently started a research project to generate such data, subsequently to develop and to improve numerical methods for the analysis of impact limiters and damping foundation material and thus to optimize safety assessment tools for the design of transport and storage casks. A major part of this research concerns dynamic compression tests of variably shaped specimens conducted at a servo hydraulic 1MN impact testing machine as well as at a BAM facility for guided drop tests. This presentation focuses 100mm damping concrete cubes deformed vertically at constant rates under different constraint conditions. For example, a special fitting jig was constructed to subject the specimens to multi-axial loading. Thereby a deformation of 60% could be applied. Simulation was conducted by FE code ABAQUS™ based on material models “Concrete damaged plasticity” and “Crushable foam” which both allow defining rate sensitive nonlinear stress-strain relations in compression beyond the classic metal plasticity approach. T2 - PATRAM 2010 - 16th International symposium on the packaging and transport of radioactive materials CY - London, UK DA - 2010-10-03 KW - Damping concrete KW - Strain rate sensitivity KW - Numerical simulation KW - Material model PY - 2010 SP - 1-8 (Thursday-T40-114) AN - OPUS4-23708 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheidemann, Robert A1 - Kasparek, Eva Maria A1 - Qiao, Linan A1 - Müller, Karsten A1 - Droste, Bernhard A1 - Völzke, Holger T1 - Dynamic penetration tests on shock absorbing damping concrete T2 - WM2014 Conference CY - Phoenix, Arizona, USA DA - 2014-03-02 KW - Drop test KW - Dynamic KW - Penetration KW - Damping concrete PY - 2014 SN - 978-0-9836186-3-8 SP - Paper 14166, 1 EP - 9 AN - OPUS4-31948 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Investigation programme for evaluation and prediction of the long-term behaviour of Helicoflex® metal seals N2 - In Germany, for the transport and storage of spent nuclear fuel, casks with double closure lid systems are used, which are equipped with Helicoflex® metal seals. The original interim storage period for these casks was planned to be 40 years. However, recent political developments indicate that a storage time of more than 80 years might be necessary. Therefore, the current storage licenses have to be renewed in due course, which requires extended knowledge of the long-term behaviour of all cask components. At the Bundesanstalt für Materialforschung und -prüfung (BAM), metal seals have been investigated after ageing at temperatures between room temperature and 150 °C for up to 7 years. At regular intervals the seals have been tested for leakage rate as well as for their mechanical behaviour. From these tests pronounced influence of ageing could be shown which results in the decrease of the seal force and the useable resilience. The main reason attributed to these performance changes is the increasing permanent deformation of the outer layer of the seal due to creep. So far, an explicit analytical description of the long-term behaviour that could be used for predictions exceeding the tested ageing times and temperatures was not suitable. In addition to the component tests that were already conducted, a comprehensive investigation programme has been started to describe the mechanical behaviour of the individual seal components. The individual seal components are tested regarding different material characteristics including creep, deformation and microstructural properties. The comparability of the material characterization is ensured by comparing the basic raw material of the specimen with the actual component material. Furthermore, detailed investigations of the time and temperature dependent deformation behaviour are realized by ageing seal segments at multiple temperatures for different periods of time and employing standardized tests. By analysing the acquired data in combination with the ongoing long-term component tests a dataset for analytical prediction of the long-term behaviour of the seals is intended for an extended period of time under a certain temperature regime. T2 - 48th Annual Meeting on Nuclear Technology (AMNT 2017) CY - Berlin, Germany DA - 16.05.2017 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2017 SP - 1 EP - 7 AN - OPUS4-43418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Qiao, Linan A1 - Kasparek, Eva Maria A1 - Völzke, Holger A1 - Zencker, Uwe A1 - Scheidemann, Robert T1 - Development of a finite element model for damping concrete under severe impact loads N2 - Finite element analysis (FEA) has been carried out for investigation of damping concrete under different impact loading conditions with a built-in material model and damage criteria available in FEA code ABAQUS. At first, all parameters for the selected material model had been derived from compression Tests of cubic specimens. After that, a validation was carried out with different static and dynamic penetration tests. Finally, a 5 meter real drop test with a 23 Mg cylindrical cask could successfully be simulated. T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 18.08.2013 PY - 2013 SP - Session D, Paper 127, 1 EP - 10 PB - Omnipress AN - OPUS4-29110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Component and material investigations on metal seals for high level radioactive waste containers N2 - Long-term investigations performed at BAM look to extend the state of knowledge on safety-related components of interim storage containers. Metal seals act as the primary sealing barrier in the bolted double lid closure system of the containers. The behaviour of metal seals has been investigated for ageing times up to 8.5 years and for various temperatures. The main cause for reduction in useable resilience overtime was due to creep deformation of the outer jacket of the seal. KW - Metal seal KW - Radioactive waste containers KW - Creep KW - Long-term behaviour PY - 2018 SN - 1745-2058 SP - 32 EP - 34 PB - Nuclear Institute CY - London AN - OPUS4-48206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Neumeyer, Tino A1 - Wieser, Günter T1 - Status and Developments in Design Testing and Licensing on Non-Heat Generating T2 - 4th International Seminar on Radioactive Waste Products CY - Würzburg, Germany DA - 2002-09-22 PY - 2002 AN - OPUS4-5746 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Kömmling, Anja A1 - Wolff, Dietmar A1 - Völzke, Holger ED - Stuke, M. T1 - Long-term evaluation of sealing systems for radioactive waste packages N2 - The investigation of the long-term performance of sealing systems employed in containers for radioactive waste and spent nuclear fuel is one research focus area for division 3.4 “Safety of Storage Containers” at the Bundesanstalt für Materialforschung und -prüfung (BAM). Our investigations comprise investigations on metallic and elastomeric seals and covers experimental investigations to get a database on the component/material behaviour, work on analytical descriptions and numerical analysis. Our aim is to understand the long-term behaviour of the sealing systems for evaluation of their performance during possible extended interim storage and subsequent transportation. T2 - 3rd Workshop on Safety of Extended Dry Storage of Spent Nuclear Fuel CY - Garching, Germany DA - 05.06.2019 KW - Seal performance KW - Rubber seal KW - Metallic seal KW - Ageing PY - 2019 SP - 57 EP - 62 AN - OPUS4-48225 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Update on the German approach of storing spent nuclear fuel in dual purpose casks until final disposal N2 - 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. T2 - ANS Conference International High-Level Radioactive Waste Management (IHLRWM) 2017 CY - Charlotte, NC, USA DA - 09.04.2017 KW - Spent Fuel KW - Storage KW - Disposal PY - 2017 AN - OPUS4-40303 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kasparek, Eva Maria A1 - Völzke, Holger A1 - Scheidemann, Robert A1 - Zencker, Uwe T1 - Numerical and experimental investigations of polyurethane foam for use as cask impact limiter in accidental drop scenarios T2 - WM2012 - Waste management conference CY - Phoenix, AZ, USA DA - 2012-02-26 KW - Plasticity KW - Finite elements KW - Material models KW - Rate dependency KW - Temperature dependency KW - Compression tests KW - Drop tests KW - Parameter identification PY - 2012 SN - 978-0-9836186-1-4 N1 - Serientitel: WM Symposia – Series title: WM Symposia IS - Paper 12099 SP - 1 EP - 9 AN - OPUS4-26270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kasparek, Eva Maria A1 - Völzke, Holger A1 - Scheidemann, Robert A1 - Zencker, Uwe A1 - Wolff, Dietmar T1 - Experimental and numerical studies of shock absorbing materials for containers for radioactive waste PY - 2012 SN - 1431-5254 VL - 57 IS - 6 SP - 397 EP - 401 PB - Inforum CY - Berlin AN - OPUS4-26261 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Zencker, Uwe A1 - Völzke, Holger A1 - Schulze, Dietmar A1 - Probst, Ulrich T1 - Testing and Numerical Simulation of Elastomers - From Specimen Tests to Simulation of Seal Behavior under Assembly Conditions N2 - Due to delays in the siting procedure to establish a deep geological repository for spent nuclear fuel and high level radioactive waste as well as in construction of the already licensed Konrad repository for low and intermediate level radioactive waste, extended periods of interim storage become more relevant in Germany. BAM is involved in most of the cask licensing procedures and especially responsible for the evaluation of cask-related long-term safety issues. The long-term performance of elastomer seals for lid systems of transport and storage casks, whether used as auxiliary seals in spent fuel casks or as primary seals for low and intermediate level waste packages, is an important issue in this context. The polymeric structure of these seals causes a complex mechanical behavior with time-dependent sealing force reduction. The results of a comprehensive purpose-designed test program consisting of basic compression and tension tests as well as relaxation tests on unaged specimens of representative types of elastomers (fluorocarbon rubber (FKM) and ethylene propylene diene rubber (EPDM)) at different temperatures and strain rates are presented. They were used to identify the constitutive behavior and to obtain parameters for finite element material models provided by the computer code ABAQUS®. After estimating the influence of uncertainties such as Poisson’s ratio and friction coefficient by sensitivity analyses, the chosen parameters had to prove their suitability for the finite element simulation of the specimen tests themselves. Based on this preliminary work the simulation of a specific laboratory test configuration containing a typical elastomer seal with circular cross section is presented. The chosen finite element material model and the implemented parameters had to show that they are able to represent not only the specimen behavior under predominantly uniaxial load but also the more complex stress states in real components. Deviations between the measured and calculated results are pointed out and discussed. For the consideration of long-term effects in the simulation of elastomer behavior, test results of aged specimens are needed. First information about a new test program, started recently and planned to provide these data, are given. T2 - ASME 2017 Pressure Vessels & Piping Conference (PVP2017) CY - Waikoloa, Hawaii, USA DA - 16.07.2017 KW - Time dependent effects KW - Low temperature behavior KW - Elastomeric seals KW - Aging KW - Simulation KW - Testing PY - 2017 SN - 978-0-7918-5802-8 VL - 7 SP - Article UNSP V007T07A035, 1 EP - 8 AN - OPUS4-41841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaunich, Matthias A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Stark, Wolfgang T1 - Understanding low temperature properties of elastomer seals N2 - Elastomers are widely used as the main sealing materials for containers for low and intermediate level radioactive waste and as an additional component to metal seals in spent fuel and high active waste containers. The safe encapsulation of the radioactive container inventory has to be guaranteed according to regulation and appropriate guidelines for long term storage periods as well as for temperatures as low as -40°C during transport. Therefore, the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of elastomers are strongly temperature dependent. At low temperatures, this is caused by the rubber-glass transition (abbreviated: glass transition). During continuous cooling, the material changes from a rubber-like entropy elastic to a stiff energy elastic behaviour, which allows nearly no strain or retraction. Hence, rubbers are normally used above their glass transition, but the minimum working temperature limit is not defined precisely; this can cause problems during the above noted applications. Therefore, the lower operation temperature limit of elastomer seals must be determined in dependence of the material properties. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) are combined with standardised measurements to determine the compression set according to ISO 815. To reduce the test time of the standard tests, a faster technique than normally used was developed. Additionally, the breakdown temperature of the sealing function of complete O ring seals was measured in a component test set-up to compare it with the results of the other tests. The experimental set-up is capable of measuring the leakage rate at low temperatures by the pressure rise method. A fluorocarbon rubber (FKM) was selected for this investigation as it is often used for radioactive waste containers. The materials (seals and test sheets) were purchased from a commercial seal producer. KW - Sealing material KW - Elastomer KW - Compression set KW - Dynamic mechanical analysis KW - Low temperature behaviour PY - 2011 DO - https://doi.org/10.1179/1746510911Y.0000000004 SN - 1746-5095 SN - 1746-5109 SN - 0957-476X VL - 22 IS - 2 SP - 83 EP - 88 PB - Ramtrans Publ. CY - Ashford AN - OPUS4-24015 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Wille, Frank A1 - Wieser, Günter A1 - Quercetti, Thomas T1 - Transport and Storage Cask Safety Assessment - Drop Tests and Numerical Calculations T2 - Waste Management Symposium 2006 CY - Tucson, Az. USA DA - 2006-02-26 KW - Transportbehälter KW - Lagerbehälter KW - Radioaktive Stoffe KW - Fallversuch KW - FEM KW - Sicherheit PY - 2006 SP - 12 pages CY - Tucson AN - OPUS4-12536 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kasparek, Eva Maria A1 - Zencker, Uwe A1 - Scheidemann, Robert A1 - Völzke, Holger A1 - Müller, Karsten T1 - Numerical and experimental studies of polyurethane foam under impact loading N2 - Proper predictions of the behaviour of shock absorber materials are of utmost importance in safety assessments for licensing casks for transport and storage of highly active waste. After having identified significant discrepancies between numerical results and the actual response of polyurethane foam limiters subjected to accidental scenarios, a new research project ENREA was established by BAM. A major objective is to enhance and to develop advanced material models intended to simulate limiters under impact loading. They should account for all major factors influencing the load–deformation relationship like temperature, strain rate and specific stress state. The corresponding test program, applicable plasticity models, the overall parameter identification strategy based on local and global optimization techniques as well as experimental and numerical results are presented here in particular for closed cell foams. KW - Polyurethane foam KW - Limiter KW - Impact loading KW - Strain rate KW - Plasticity model KW - Parameter identification PY - 2011 DO - https://doi.org/10.1016/j.commatsci.2010.11.025 SN - 0927-0256 VL - 50 IS - 4 SP - 1353 EP - 1358 PB - Elsevier CY - Amsterdam AN - OPUS4-23151 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - von der Ehe, Kerstin A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Stark, Wolfgang T1 - Understanding the low temperature properties of rubber seals N2 - Rubbers are widely used as main sealing materials for containers for low and intermediate level radioactive waste and as additional component to metal seals in spent fuel and high active waste containers. The save encapsulation of the radioactive container inventory has to be guaranteed according to legislation and appropriate guidelines for long term storage periods as well as down to temperatures of -40 °C during transport. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. It is known that the material properties of rubbers are strongly temperature dependent. At low temperatures this is caused by the rubber-glass transition (abbr. glass transition). During continuous cooling the material changes from rubber-like entropy-elastic to stiff energy-elastic behaviour, that allows nearly no strain or retraction, due to the glass transition. Hence rubbers are normally used above their glass transition but the minimum working temperature limit is not defined precisely, what can cause problems during application. Therefore the lower operation temperature limit of rubber seals should be determined in dependence of the material properties. The results of Differential Scanning Calorimetry (DSC) and Dynamic Mechanical Analysis (DMA) are combined with the results of standardized measurements as the compression set according to ISO 815. To reduce the test time of the standard tests a faster technique was developed. Additionally, the breakdown temperature of the sealing function of complete O-ring seals is measured in a component test setup to compare it with the results of the other tests. The experimental setup is capable of measuring the leakage rate at low temperatures by the pressure rise method. A fluorocarbon rubber (FKM) was selected for this investigation as it is often used for radioactive waste containers. Some materials (seals and test sheets) were purchased from a commercial seal producer and some materials were compounded and cured at BAM in form of rubber sheets. T2 - PATRAM 2010 - 16th International symposium on the packaging and transport of radioactive materials CY - London, UK DA - 2010-10-03 KW - Dichtungen KW - Elastomere KW - Tieftemperaturverhalten PY - 2010 SP - 1 EP - 7 (Session T41 / Paper 169) AN - OPUS4-23887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Hagenow, Peter A1 - Kasparek, Eva Maria A1 - Kömmling, Anja A1 - Noack, Volker A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Requirements for the use of elastomer seals in casks for final disposal of low and intermediate level waste N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste and in some countries for spent fuel transportation casks. Depending on the area of use, the rubber materials have to demonstrate proper sealing performance with regard to mechanical, thermal and environmental conditions as well as irradiation during the entire operation period. In Germany the low and intermediate level radioactive waste is planned to be disposed in the Konrad repository in standardized containers. Many of these containers use an elastomer seal between lid and container body. Depending on the radiactive inventory and a possible containment of the waste in inner barrels and/or concrete structures, such containers may require a specific leak tightness. In such cases, specified leakage rates are shall not be exceeded by the the seals to keep potential activity releases from the inventories well below defined limits. Generally, all waste containers have to fulfill the waste acceptance criteria for the Konrad repository as defined by the reports BfS SE-IB-29/08 and SE-IB-30/08. From these criteria several requirements for seal performance are derived. The seals have to: - ensure full functionality until final container disposal, - maintain its function in case of a thermal or mechanical accident, - ensure encapsulation also at -20 °C. This combination of requirements is challenging especially as a seal exchange, which is typical for many other applications, is hardly possible and thus a sound understanding of how to perform safety evaluation of containers is required. Therefore BAM has initiated investigations on elastomer seal behaviour. This work focuses on low temperature behaviour and sealing performance concerning static conditions as well as partial loss of compression and ageing of elastomer seals. Concerning ageing, property changes caused by long-term thermooxidative conditions as well as gamma irradiation are investigated. This contribution presents an overview and explanation of the aims of the ongoing research and gives an update of the most relevant results. T2 - 13th Internationales Symposium "Konditionierung radioaktiver Betriebs- und Stillegungsabfälle CY - Dresden, Germany DA - 22.03.2017 KW - Disposal KW - Konrad repository KW - Seal PY - 2017 SP - 595 EP - 601 AN - OPUS4-39870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Simbruner, Kai A1 - Grelle, Tobias A1 - Jaunich, Matthias A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Orellana Pérez, Teresa A1 - Völzke, Holger T1 - Research at BAM for evaluating long term safety of container systems and components N2 - Safety of long term containment and storage of radioactive waste is an essential issue, which is increasingly gaining international attention. Extending interim storage beyond initial license periods is one of the major challenges worldwide. BAM has been involved in all kinds of radioactive waste container safety evaluation for storage and transportation including their long term performance from the very beginning. Today, all work related to the safe management of radioactive waste is linked by the activity field “Nuclear Waste Management” within the Focus Area “Energy” at BAM and in conjunction with a research strategy and agenda. Most recently, the working group “Long Term Safety of Container Systems and Components” was established to launch and perform research projects related to safety issues concerning the extended interim storage of radioactive waste. For example, within our project LaMEP, we investigate ageing effects of metal and elastomer seals as well as polymeric neutron shielding materials, which are container components that fulfil major safety functions. The results of the experiments help to understand the long term behaviour of these components. Likewise, our project BRUZL started at BAM in 2018 with the aim of developing a fracture mechanics approach to understand and describe a potential brittle failure mechanism of fuel cladding during long-term interim storage. BAM also contributes to the GRS project “Development of methods and models and international exchange for safety evaluation in the frame of interim storage of radioactive waste”. Additionally, BAM is involved in several international research programmes dealing with extended interim storage, such as the European Joint Programme on Radioactive Waste Management (EURAD), the Extended Storage Collaboration Program (ESCP) and IAEA Coordinated Research Projects. The present contribution provides a comprehensive overview of BAM research activities contributing to national and international gap analyses and to filling knowledge gaps regarding the safe long term management of radioactive waste. T2 - Annual Meeting on Nuclear Technology 2019 CY - Berlin, Germany DA - 07.05.2019 KW - Radioactive Waste KW - Long-term safety PY - 2019 SN - 978-3-926956-95-8 SP - 1 EP - 5 AN - OPUS4-51486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Kömmling, Anja A1 - Horn, Jutta A1 - Völzke, Holger A1 - Wolff, Dietmar T1 - Long-Term Performance of Elastomer seals - From Aging Tests to Lifetime Estimations N2 - Elastomers show a high versatility which makes them ideal materials for sealing applications in various fields. Especially under changing application conditions the high recovery potential of this class of material is beneficial to compensate temperature or pressure fluctuation, and geometrical changes resulting from mechanical loads in e.g. accident conditions. Out of these reasons elastomers are also used in containers for low and intermediate level radioactive waste and for spent fuel transportation casks. In casks designed for low and intermediate level waste elastomer seals can act as primary seal responsible for the containment function whereas in spent fuel storage and transportation casks (dual purpose casks (DPC)) elastomer seals are used as auxiliary seals to allow leakage rate measurements of metal barrier seals. An inherent prerequisite for this kind of application is the Long time-scale of operation without or with limited possibility of seal replacement. In Germany an interim storage license for DPC`s is typically issued for 40 years, a timeframe which might increase in the future due to challenges of the final repository siting procedure. For low and intermediate level waste, also long time periods are required before final disposal can be achieved. Therefore, the performance of elastomer seals over extended time periods is, as for other applications, of high importance. A typical approach to ensure long-term functionality is to perform accelerated aging tests to calculate an estimated lifetime by assuming e.g. Arrhenius like equations for the timetemperature relationship. This approach requires a suitable end of life criterion considering the application of interest. This often can represent a challenge on its own. As BAM is involved in most of the cask licensing procedures and especially responsible for the evaluation of cask-related long-term safety issues we initiated several test programs for investigating the behavior of elastomer seals. Experiments concerning the low temperature performance down to -40 °C and the influence of gamma irradiation have been started first. Currently the thermal aging behavior of elastomer seals, which is the topic of this contribution, is examined. For our aging investigations we use a broad approach to first determine the property changes in different elastomer materials due to thermo-oxidative aging at elevated temperatures and secondly, we test how the typical methods of lifetime extrapolation can be applied to these results. This Approach enables us to detect and exclude undesired side effects which very often influence lifetime estimations. In this contribution, our recent results are extended. The results show that lifetime estimation based on single material properties can be misleading and therefore a combination of several methods is recommended. T2 - ASME 2018 Pressure Vessels and Piping Conference CY - Prague, Czech Republic DA - 15.07.2018 KW - Seal performance KW - Rubber KW - Ageing PY - 2018 VL - PVP2018 SP - 84631-1 EP - 84631-8 AN - OPUS4-46346 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Zencker, Uwe A1 - Völzke, Holger A1 - Schulze, Dietmar T1 - Testing and numerical simulation of elastomeric seals under consideration of time dependent effects N2 - Due to delays in the siting procedure to establish a deep geological repository for spent nuclear fuel and high level waste and in construction of the already licensed Konrad repository for low and intermediate level waste, extended periods of interim storage will become more relevant in Germany. BAM is involved in most of the cask licensing procedures and is responsible for the evaluation of cask-related long-term safety issues. Elastomeric seals are widely used as barrier seals for containers for low and intermediate level radioactive waste. In addition they are also used as auxiliary seals in spent fuel storage and transportation casks (dual purpose casks (DPC)). To address the complex requirements resulting from the described applications, BAM has initiated several test programs for investigating the behavior of elastomeric seals. These include experiments concerning the hyperelastic and viscoelastic behavior at different temperatures and strain rates, the low temperature performance down to -40°C, the influence of gamma irradiation and the aging behavior. The first part of the paper gives an overview of these tests, their relevant results and their possible impact on BAM’s work as a consultant in the framework of approval and licensing procedures. The second part presents an approach of the development of a finite element model using the finite element code ABAQUS®. The long-term goal is to simulate the complex elastomeric behavior in a complete lid closure system under specific operation and accident conditions. T2 - ASME 2016 Pressure Vessels & Piping Conference (PVP2016) CY - Vancouver, BC, Canada DA - 17.07.2016 KW - Elastomeric seals KW - Testing KW - Low temperature behavior KW - Aging KW - Simulation KW - Time dependent effects PY - 2016 SN - 978-0-7918-5045-9 VL - 7 SP - Paper 63192, 1 EP - 10 AN - OPUS4-37046 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -