// Long-term Safety Studies

P&T

The impact of partitioning and transmutation on repository concepts and the long-term safety of repositories for heat-generating radioactive waste.

In this project, the objective was to investigate whether and to what extent the long-term impacts emanating from a repository can be reduced by separating long-lived radionuclides (primarily actinides) from spent fuel elements of German light-water reactors and subsequently transmuting them into shorter-lived radionuclides. The project operated on the premise of the German government's decision to phase out nuclear energy, thereby limiting the inventories of radioactive waste requiring disposal. Additionally, it assumed that the existing high-level waste from reprocessing would not be affected by partitioning and transmutation (P&T).

Using data from the recently completed Preliminary Safety Analysis for Gorleben (VSG), inventory data and repository concepts were compiled for the case without P&T for repositories in salt formations. Expected changes regarding inventories and repository concepts were derived from these documents under the assumption of P&T. Analogous considerations were made for repository systems in clay formations.

For a repository containing heat-generating waste in Germany, the impacts of P&T were found to be not significant. The required repository footprint, for instance, would at best be halved. This is mainly due to the presence of existing high-level waste from reprocessing. Additionally, the dismantling of the facilities required for P&T and the production of additional negligibly heat-generating waste contribute to the need for an additional repository. Since P&T does not influence the fission products (e.g., iodine) relevant for long-term safety, the authors conclude that P&T is of little relevance for the long-term safety of repositories concerning the radioactive waste to be disposed of in Germany. Solely comparing the radiotoxicity of radioactive waste in Germany (with and without P&T) is insufficient for assessing long-term safety.