RADIOACTIVE WASTE ISOLATION IN SALT: SPECIAL ADVISORY REPORT ON THE STATUS OF THE OFFICE OF NUCLEAR WASTE ISOLATION'S PLANS FOR REPOSITORY PERFORMANCE ASSESSMENT

Repository performance assessment is analysis that identifies events and processes that might affect a repository system for isolation of radioactive waste, examines their effects on barriers to waste migration, and estimates the probabilities of their occurrence and their consequences. In 1983 Battelle Memorial Institute&#39;s Office of Nuclear Waste Isolation (ONWI) prepared two plans — one for performance assessment for a waste repository in salt and one for verification and validation of performance assessment technology. At the request of the U.S. Department of Energy&#39;s Salt Repository Project Office (SRPO), Argonne National Laboratory reviewed those plans and prepared this report to advise SRPO of specific areas where ONWI&#39;s plans for performance assessment might be improved. <br/><br/>This report presents a framework for repository performance assessment that clearly identifies the relationships among the disposal problems, the processes underlying the problems, the tools for assessment (computer codes), and the data. In particular, the relationships among important processes and 26 model codes available to ONWI are indicated. A common suggestion for computer code verification and validation is the need for specific and unambiguous documentation of the results of performance assessment activities.<br/><br/>A major portion of this report consists of status summaries of 27 model codes indicated as potentially useful by ONWI. The code summaries focus on three main areas: (1) the code&#39;s purpose, capabilities, and limitations; (2) status of the elements of documentation and review essential for code verification and validation; and (3) proposed application of the code for performance assessment of salt repository systems.