Proposal for systematic application of BEPU in the licensing process of Nuclear Power Plants

Abstract: In general, Best Estimate Plus Uncertainty (BEPU) methodology implies application of 'realistic' or the so-called 'best estimate' computational codes with uncertainty quantification to the thermal-hydraulic safety analyses of nuclear power plants within the licensing process. The results of such analyses are documented in Chapter 15 of Final Safety Analysis Report (FSAR). The objective of the present work is to discuss the possibility of adopting BEPU methodology to the entire FSAR, therefore extending its application range to the other chapters. To perform an entire FSAR based on BEPU, a homogenisation of the analysis is proposed. The first step towards BEPU-FSAR requires identification and characterisation of the parts where numerical analyses are needed (the so-called BEPU topics). The next step is to create a list of key technological areas, the so-called key disciplines and their related key topics and then an overview of the currently computational activities in each technological area. Based on the finalised BEPU applications one can conclude that this methodology is feasible, which encourages to extended its range of use to the other technological areas of FSAR, and therefore to demonstrate the industrial worth and interest. The future step of this work will mainly be focused on the propagation of this expertise into the remaining technical areas of FSAR, adding new knowledge and therefore creating coherent and rigorous background of the BEPU-FSAR methodology