Adoption of the NUTEMA KM Tool.for Pursuing BEPU Approach in Licensing

The safety analysis report of a nuclear power plants NPP for licensing typically comprises a chapter on accident analysis. The licensee has to postulate a number of initiating events, and has to demonstrate that the NPP is capable to cope with the event (by comparing key figures like peak clad temperature against preset acceptance criteria). The licensee may choose a conservative approach for the analysis (i.e. conservative computer codes and initial conditions); in this case the results of the analysis will be directly compared against the preset acceptance criteria. The licensee may also adopt a best estimate approach (best estimate computer codes), but has to evaluate the connected uncertainty, and has to compare code result plus uncertainty against acceptance criteria. The University of Pisa performed the accident analysis for the safety analysis report for the nuclear power plant Atucha 2. The Best Estimate Plus Uncertainty BEPU approach has been chosen for all postulated initiating events. BEPU offers the advantage of showing a more likely plant behavior, but increases considerably the computational effort. Results from roughly twenty computer codes and forty code models, as well as the codes and code models themselves had to be managed. To keep track of models, computer codes, calculation results, a tool has been developed – NUclear TEchnology Knowledge MAnagement System (NUTEMA). The present paper introduces key features of NUTEMA and provides an overview on the help NUTEMA can give to knowledge management.