Framework and Strategies for the Introduction of Best Estimate Models into the Licensing Process

The current efforts to assure stable, safe and competitive operation of nuclear power plants go together with advances made in accident analysis domain where the deterministic safety analysis is an important instrument for confirming the adequacy and efficiency of provisions for the safety of nuclear power plants. Recently made advances offer two acceptable options for demonstrating that the safety is ensured with sufficient margin: use of best estimate (BE) computer codes either combined with conservative input data or with realistic input data but associated with evaluation of uncertainty of results. The objective, proposed for the present work, is the implementation of the best estimate plus uncertainty (BEPU) method into the licensing process, as developed by the University of Pisa in a PhD thesis. In the thesis activity, more emphasis is given to the study of “input and method” of BE calculations than on “uncertainty evaluation”. In the present paper, a summary of the results achieved is reported.