BEPU-FSAR: DISCUSSION OF V&V PRINCIPLES APPLICATION TO NON THERMAL-HYDRAULIC CODES

Nuclear thermal hydraulic and accident analysis are based in 3 pillar activities, which consists in: Scaling, Coupling and Verification and Validation (V&V). Each of them are established technology, with key documents to describe and widely used. Best Estimate Plus Uncertainty (BEPU) methodology implies application of ―realistic‖ or 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 the Chapter 15 of Final Safety Analysis Report (FSAR). The objective of the present work is to discuss upon the possibility of adopting BEPU methodology to the entire FSAR, therefore extending its application range to the other chapters and for that the crucial step is the transfer of the BEPU concepts into the other areas. In this sense, the issue is how to adapt to other disciplines the pillar activities presented in the thermal hydraulic area. For that we need to identify which elements can be applied in the other areas, to show that the proposed methodology is feasible. For now, this work aims to show that the V&V elements, currently done for thermal-hydraulic codes, can be also done for different codes, which are used to perform different analysis included on a FSAR of a generic plant. Based on the finalized BEPU applications one can conclude that this methodology is feasible, which encourage 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.