Towards a harmonization of BEPU application in Severe Accident analysis

The EC MUSA project has been exploring the application of the Best Estimate Plus Uncertainty (BEPU) approach in Severe Accident analysis (SA) for the last four years. Major achievements have been accomplished. To name a few: a database on input deck uncertainties has been assembled; severe accident codes and statistical tools, either in-house built or existing ones, have been properly coupled by scripting necessary interfaces; major specific challenges have been identified and different solutions have been worked out; and, applications to several reactor types (Gen. II and Gen. III) and spent fuel pool scenarios have shown interesting insights of this simulation approach, particularly when dealing with Source Term variables as figures of merit. In short, the community is ready to face the final necessary step to make BEPU a powerful and broadly used approach for severe accident simulation: its harmonization. In other words, a consolidated and systematic methodology independent of any specific SA and statistical tool needs to be developed. To do so, a new initiative, called INNOMUSA, is being built. Emphasis will be given to the effect of uncertainties on accident management and, vice versa, the effect of accident management on uncertainties. In the scope of the INNOMUSA attention is planned to be paid to near-term advanced technology fuels (ATFs) and light water small modular reactors (LWSMRs).