Derivation of host rock-specific temperature tolerance of repository components. Claystone

In the site selection process for the final storage of high-level radioactive waste, in accordance with Section 27 Paragraph 4 of the StandAG, the preliminary safety investigations have so far assumed a maximum temperature of 100 °C on the surface of the waste containers as a precautionary measure in order to rule out possible negative consequences for the functionality of the components of the final storage system (ESS). This limit is assumed regardless of the respective host rock as long as pending research work does not allow the temperature limit to be specified. The Waste Management Commission /ESK 22/, on the other hand, recommends that the requirements with regard to temperature distribution and development in an ELS be formulated on a host rock or site-specific basis. The aim of the report is to provide a basis to support a decision as to which host rock-specific limit temperatures (or design temperatures to be specified during design) are to be taken into account in the rvSU. This decision is important for the site selection process so that potentially suitable sites are not eliminated from the site selection process due to Section 27 Paragraph 4 of the StandAG. In addition to providing the scientific basis, the report contains a derivation of a temperature for the host rock, claystone, that is favorable for the safety of the repository. This evaluation is to be understood as the authors' contribution to the discussion on limit temperatures. The evaluation is carried out from the perspective of the long-term safety of the repository system and includes all processes taking place in the repository.