TY - CONF A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Low temperature properties of rubber seals - influence of gamma irradiation N2 - Rubbers are widely used as sealing material in various applications. In many fields, the function of seal materials at low temperatures is required. Therefore the understanding of failure mechanisms that lead to leakage at low temperatures is of high importance. KW - Compression set KW - Irradiation KW - O-ring KW - Seal PY - 2014 SN - 978-3981407624 SP - 1 EP - 7 AN - OPUS4-32326 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Wolff, Dietmar T1 - Investigation of elastomer seal behaviour for transport and storage packages N2 - According to the relevant guidelines and regulations, the safe enclosure of radioactive Container contents has to be guaranteed for long storage periods as well as down to temperatures of -40 °C during transportation. As rubbers are widely used as the 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, a comprehensive eiastomer investigation Programme is in place at BAM. This Programme comprises investigations of overall eiastomer performance, durability, influence of gamma irradiation and low temperature behaviour. In this paper we focus on the behaviour of eiastomer seals at low temperatures with regard to the potential increase in leakage as material properties of rubbers are strongly temperature-dependent. During continuous cooling, the material behaviour of elastomers changes in the rubber-glass transition temperature ränge from rubberlike entropy-elasticity to stiff energy-elasticity, allowing for almost no strain or retraction. Hence rubbers are normally used above their rubber-glass transition but the minimum limit at which they work has not been defined precisely. For the investigations, fluorocarbon (FKM) and ethylene-propylene-diene (EPDM) rubbers were selected, as they are often used in radioactive waste Containers. The elastomers were studied using several thermoanalytical methods and compression set. The results were compared with component tests to determine the temperature at which the sealing function of O-rings made of eiastomer breaks down. In addition to these results, under static conditions we designed a new measurement set-up which allows for a small deflection of the flange and simultaneous leakage rate measurement at low temperatures. T2 - RAMTRANS 2015 - 10th International conference on radioactive materials transport and storage CY - Oxford, UK DA - 19.05.2015 KW - O-ring KW - Glass-rubber transition KW - Irradiation KW - Compression set PY - 2015 SP - 1 EP - 10 AN - OPUS4-33489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, T. A1 - Wolff, Dietmar T1 - Influences on the low temperature sealability of elastomer O-rings N2 - For many sealing applications rubbers are applied due to their special material properties and easy use. In many applications, e.g. in aviation, traffic or process technology the material can be exposed to low temperatures during Operation. Therefore it is important to know the material behaviour at those low temperatures to determine the temperature range that allows a safe Operation of the seal. As rubbers are 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, a comprehensive elastomer investigation program is run at BAM. This program comprises investigations of elastomer overall performance, durability, influence of gamma irradiation and low temperature behaviour. In this paper we focus on the behaviour of elastomer seals at low temperatures with regard to potential decrease of leak-tightness as material properties of rubbers are strongly temperature dependent. But additionally to the investigation presented in the past which considered the material properties of new materials and the seal behaviour under purely static conditions [1, 2] we now focus on irradiated materials and on the sealing performance after a fast partial release of the compressed seal. For the investigations different materials were used, e.g. fluorocarbon (FKM) and ethylenepropylene-diene (EPDM) rubber. To determine the effect of gamma irradiation some samples were irradiated and studied by several thermo-analytical methods and compression set. For the investigation of the seal performance under non static conditions we decided to design a new measurement setup which allows for a small flange deflection and simultaneous leakage rate measurement at low temperatures. T2 - IRC 2015 - International rubber conference CY - Nuremberg, Germany DA - 29.06.2015 KW - O-ring KW - Glass-rubber transition KW - Irradiation KW - Compression set PY - 2015 SP - 1 EP - 7 AN - OPUS4-33784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Weber, Mike A1 - Kömmling, Anja A1 - Zencker, Uwe A1 - Wolff, Dietmar A1 - Völzke, Holger T1 - Performance of elastomer seals in transport and storage casks N2 - Elastomer seals are widely used as barrier seals in containers for low and intermediate level radioactive waste and for spent fuel transportation casks. In addition, they are also used for spent fuel storage and transportation casks (dual purpose casks (DPC)) as auxiliary seals to allow leakage rate measurements of metal barrier seals for demonstration of their proper assembling conditions. 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. Concerning DPC, degradation effects should be limited in a way that, for example, effects from potentially released decomposition elements may not harm e.g. metal barrier seals. Leakage rate measurements should be possible also after long interim storage periods prior to subsequent transportation. Because of the complex requirements resulting from the various applications of containers for radioactive waste and spent nuclear fuel, BAM has initiated several test programmes for investigating the behaviour of elastomer seals. In this contribution the current status is described and first results are discussed. T2 - International conference on management of spent fuel from nuclear power reactors: An integrated approach to the back end of the fuel cycle CY - Vienna, Austria DA - 15.06.2015 KW - Ageing KW - Elastomer KW - Glass-rubber transition KW - Irradiation KW - Material model PY - 2015 SP - 1 EP - 8 AN - OPUS4-33553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zaghdoudi, Maha A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar A1 - Albouy, P.-A. A1 - Häcker, Ralf A1 - Stock, Daniel T1 - Overview of ongoing research and future prospects on polyethylene neutron shielding materials at bam N2 - The extension of the interim storage period of radioactive waste before disposal will cause additional challenges for the nuclear waste management in Germany, so that an extensive knowledge of the long-term performance of casks, including their components and inventories, will be required for future extended storage licenses. Ultra-high and high molecular weight polyethylenes ((U)HMW-PE) are used for neutron shielding purposes in casks for storage and transport of spent fuel and high-level waste due to their extremely high hydrogen content. During their service life of several decades as cask components, the PE materials are exposed to neutron and gamma radiation from the radioactive inventory of the casks, mechanical assembling stresses and temperature. All these combined effects affect the material properties of such components which in turn may be crucial for some possible accident scenarios. At the Bundesanstalt für Materialforschung und -prüfung (BAM), the effects of high temperature exposure in combination with subsequent or previous irradiation were investigated with a comprehensive aging program including thermal aging at 125 °C for different aging periods up to 5 years and irradiation with doses ranging from 50 to 600 kGy. This contribution provides an overview of the ongoing research related to the structural changes of (U)HMW-PE induced by gamma irradiation and high temperature exposure and focuses on current research perspectives at BAM with regard to the prediction of the dynamic behavior of the material during extended interim storage in case of an accident scenario. First results of the coupled effect of temperature, radiation and mechanical loading will be presented. The effect of microstructural changes induced by gamma irradiation and high temperature on the mechanical behavior of (U)HMW-PE will be assessed. T2 - PATRAM22 CY - Juan-Les-Pins, Antibes, France DA - 11.06.2023 KW - (U)HMWPE KW - Ageing KW - Irradiation KW - WAXD KW - SHPB PY - 2023 SP - 1 EP - 10 AN - OPUS4-57707 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -