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 - Völzke, Holger A1 - Wolff, Dietmar T1 - Safety aspects of long dry interim cask storage of spent fuel in Germany N2 - Dry cask storage of spent fuel and high active waste front reprocessing is licensed and established in Germany for up to 40years so far. About 10years ago, the strategy has been shifted from centralized storage using facilities in Ahaus and Gorleben to cit-site storage facilities in Order to avoid immediate cask shipping from nuclear power plants. At present, several hundred casks are stored safeiy and without any major problem. BAM is highly involved in cask specific safety evaluations within the scope of licensing procedures as well as of quality assurance procedures during cask fabrication, loading and storage. A major prerequisite for any cask storage license is a valid transport Type B license. Subsequently, cask transportability has to be ensured at any point during the entire storage period. So far, this requirement is met by continuous maintenance of the Type B license. Anyhow, IAEA Type B regulations do not consider permanently loaded storage casks that have the sole purpose of being finally shipped öfter decades of storage inducing ageing effects. No transport safety demonstration has to be performed on aged cask components. T2 - International high-level radioactive waste management conference (IHLRWMC 2011) CY - Albuquerque, NM, USA DA - 10.04.2011 KW - Safety KW - Cask KW - Interim storage KW - Spent fuel PY - 2011 SP - 712 EP - 719 AN - OPUS4-23651 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wille, Frank A1 - Wolff, Dietmar A1 - Droste, Bernhard A1 - Völzke, Holger T1 - Requirements for transport packages after interim storage N2 - In Germany the concept of dry interim storage of spent fuel and vitrified high active waste 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 guidelines of the German Reactor Safety Commission for dry interim storage of spent fuel. Currently part of the assessment process of the cask design for transport on public routes is to evaluate the suitability of the used materials with respect to their properties and their compatibility for possible transport periods. For transport on public routes during or after long term interim storage periods, it has to be ensured that the transport and storage casks fulfill the specifications of the transport approval or other sufficient properties which satisfy the proofs for the compliance of the safety objectives at that time. This paper describes the state-of-the-art technology in Germany and points out arising prospective challenges and which related questions have to be answered in future. Present research and knowledge concerning the long term behavior of transport and storage cask components (such as gaskets and shielding components) have to be consulted as well as experiences from interim cask storage operations. Challenges in the safety assessment are therefore i.e. the behavior 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 (aged package). Assessment methods for the material compatibility, the behavior of fuel assemblies and the aging behavior of shielding parts (e. g. influence of radiation) are further issues as well. T2 - 52nd INMM Annual meeting CY - Palm Desert, CA, USA DA - 17.07.2011 KW - Transport package design KW - Interim storage KW - Inspections KW - Log term behavior KW - Dual purpose casks PY - 2011 SP - 1 EP - 9 AN - OPUS4-24172 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger A1 - Probst, Ulrich A1 - Wolff, Dietmar A1 - Nagelschmidt, Sven A1 - Schulz, Sebastian T1 - Seal and closure performance in long term storage T2 - PSAM 11 ESREL 2012 - 11th International probabilistic safety assessment and management conference & The annual european safety and reliability conference CY - Helsinki, Finland DA - 2012-06-25 KW - Metal seal KW - Interim storage KW - Long term performance PY - 2012 SP - 1 EP - 8(?) AN - OPUS4-26175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weber, Mike A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Herbrich, Uwe A1 - Nagelschmidt, Sven T1 - Numerical analysis of cask accident scenarios in storage facilities 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 have 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 occurred which will make extended storage periods necessary in the future. T2 - PATRAM 2013 - 17th International symposium on the packaging and transportation of radioactive materials CY - San Francisco, CA, USA DA - 18.08.2013 KW - Numerical analysis KW - Interim storage KW - Cask accident scenario PY - 2013 SP - Session H, Paper 202, 1 EP - 9 PB - Omnipress AN - OPUS4-30227 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 U6 - 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 - Weber, Mike A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Völzke, Holger A1 - Herbrich, Uwe A1 - Nagelschmidt, Sven T1 - Numerical analysis of cask accident scenarios in storage facilities N2 - Mechanical drop test scenarios for Type B (U) packages according to the IAEA regulations have to be carried out onto the so-called “unyielding target” (usually with cask impact limiters) and onto the puncture bar respectively. They are predefined and do not require any further investigation of scenarios that really could happen on transportation routes. Cask accident scenarios in the framework of approval procedures for interim storage sites are derived from a detailed analysis of the handling procedures necessary from arrival of cask at the site to its storing position. In that case, casks are usually handled without impact limiters. Dependent on possible drop heights, drop positions and floor properties, conservative cask accident scenarios are derived for further safety proofs. According to the mechanical assessment concept of the considered approval procedure numerical calculations have to be provided by the applicant to demonstrate mechanical cask safety. Stresses and strains in the cask body as well as in the lid System have to be identified and assessed. Using the example of a 3-mvertical-drop of a transport and storage cask for spent fuel elements onto the floor construction made of damping concrete covered by screed, BAM developed a finite element model. The finite element code ABAQUS/Explicit™ was used. Results of experimental investigations are not available. Therefore parameter studies are necessary to identify the sensitivity of the finite element model to significant Parameters and to verify the finite element models according to the requirements of the Guidelines for the Numerical Safety Analyses for the Approval of Transport and Storage Casks for Radioactive Materials (BAM GGR-008). The paper describes the modeling of the material behavior and attachment of bottom side cask components. Questions concerning the modeling of a crack length limiting reinforcement in the screed layer are discussed. The influence of the mesh density of the screed layer and its strength is considered as well. Finally, the developed finite element model can be used for a numerical safety assessment. It can help to understand the complex mechanisms of the interaction between the cask components and floor construction. T2 - WM2014 Conference CY - Phoenix, Arizona, USA DA - 02.03.2014 KW - Numerical analysis KW - Interim storage KW - Cask accident scenario PY - 2014 SN - 978-0-9836186-3-8 SP - Paper 14541, 1 EP - 12 AN - OPUS4-31516 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Völzke, Holger T1 - The German aging management approach for dry spent fuel storage in dual purpose casks N2 - Since the decision by the German government to face out nuclear electricity generation the total amount of spent nuclear fuel and high level wastes from reprocessing is limited and well determined. In addition the siting and licensing procedure to establish a final repository has been ruled by a new law in the mid of 2013 and further delays are very likely until a deep geological repository may start its operation. In the meantime dry interim storage in dual purpose casks being permanently certified for interim storage as well as transportation is the established technical solution. Several on-site as well former centralized facilities are operated successfully for many years but storage licenses are generally limited to 40 years and future lifetime extensions are predictable. Permanent aging management for storage facilities and casks is necessary to demonstrate compliance with safety requirements and furthermore to gain relevant data and information about the technical conditions of the facilities and their components for future lifetime extensions. For that reason procedures and measures are currently improved and the approach is explained in this paper. In addition, the current status and latest experiences concerning periodic safety inspections and aging management measures are discussed. T2 - PSAM 12 - Probabilistic safety assessment and management CY - Honolulu, Hawaii, USA DA - 22.06.2014 KW - Interim storage KW - Dual purpose casks KW - Spent nuclear fuel KW - Aging management PY - 2014 SP - T06 - Doc.183, 1-7 AN - OPUS4-32250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zencker, Uwe A1 - Qiao, Linan A1 - Völzke, Holger T1 - Dynamic finite element analysis of cask handling accidents at storage sites N2 - The safety assessment of casks for radioactive material at interim storage facilities or in final repositories includes the investigation of possible handling accidents if clearly defined test conditions are not available from the regulations. Specific handling accidents usually are the drop of a cask onto the transport vehicle or the floor as well as the collision with the wall of the storage building or another cask. For such load cases an experimental demonstration of cask safety would be difficult. Therefore, numerical analyses of the entire load scenario are preferred. The lessons learnt from dynamic finite element analyses of accident scenarios with thick-walled cubical containers or cylindrical casks are presented. The dependency of calculation results on initial and boundary conditions, material models, and contact conditions is discussed. Parameter sets used should be verified by numerical simulation of experimentally investigated similar test scenarios. On the other hand, decisions have to be made whether a parameter or property is modeled in a realistic or conservative manner. For example, a very small variation of the initial impact angle of a container can cause significantly different stresses and strains. In sophisticated cases an investigation of simpler limit load scenarios could be advantageous instead of analyzing a very complicated load scenario. T2 - ASME 2015 Pressure vessels & piping conference - PVP2015 CY - Boston, Massachusetts, USA DA - 19.07.2015 KW - Finite element method KW - Simulation KW - Cask handling accident KW - Interim storage PY - 2015 SN - 978-0-7918-5702-1 SP - Paper 45606, 1 EP - 10 AN - OPUS4-34937 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 -