TY - CONF A1 - Grelle, Tobias A1 - Wolff, Dietmar A1 - Probst, Ulrich A1 - Jaunich, Matthias A1 - Völzke, Holger T1 - Investigation program 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 developments indicate that a storage time of more than 80 years might be necessary. Therefore, the current licensing has to be renewed, 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 aged at temperatures of up to 150 °C for up to 7 years. At regular intervals the seals have been tested for leakage rate as well as their mechanical properties. 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 seal component due to creep. So far, an explicit analytical description of the long-term behavior that could be used for predictions exceeding the tested ageing times was not suitable. In addition to the component tests that were already conducted, a comprehensive research program has been started. The aim is to gain information applicable for the prediction of the seal behaviour for an extended period of time under a certain temperature regime. 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 examinations 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 analyzing the newly acquired data in combination with the long-term component tests analytical forecasts of the long-term behavior of the seals are intended. T2 - Annual Meeting on Nuclear Technology (AMNT) CY - Berlin, Germany DA - 16.05.2017 KW - Metal seal KW - Creep KW - Long-term behavior PY - 2017 AN - OPUS4-40956 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -