The U.S. is currently re-evaluating the policy on high-level nuclear waste (HLW) management and has been studying generic disposal system environment (GDSE) concepts to support the development of a long-term strategy for geologic disposal of high-level nuclear waste. The GDSE study focuses on the comparative analysis of different GDSE options, and a salt repository is one of the options currently under study. The immediate goal of the generic salt repository study is to develop the necessary modeling tools to evaluate and improve understanding on the repository system response and processes relevant to long-term HLW disposal in salt.
This paper presents an initial version of the salt GDSE performance assessment model and discusses the preliminary analysis results, emphasizing key attributes of a salt repository that are potentially important to the long-term safe disposal of HLW. It also discusses the preliminary results on the repository response to the effects of different waste types (commercial UNF, existing DOE HLW, and reprocessing HLW), and radionuclide release scenarios (undisturbed and human intrusion). In addition, the paper elaborates on the identified knowledge gaps and path forwards for future R&D efforts to advance understanding of salt repository system performance for HLW disposal.