The Development of a Realistic LOCA Evaluation Model Applicable to the Full Range of Breaks Sizes: Westinghouse Full Spectrum LOCA (FSLOCATM) Methodology

Abstract

Recently changes in the regulatory environment toward a risk informed approach combined with more efficient and demanding fuel power cycles, and utilization of margins put more emphasis in scenarios traditionally defined as Small and Intermediate Break LOCA. As a result, Westinghouse made several upgrades and added several new functionalities to its realistic Large Break LOCA methodology based on the use of the WCOBRA/TRAC code. The new code has been renamed to WCOBRA/TRAC-TF2, for the purpose of extending the Evaluation Model (EM) applicability to smaller break sizes. The new EM is called Westinghouse Full Spectrum LOCA (FSLOCATM) Methodology and is intended to be applicable to a full spectrum of LOCAs, from small to intermediate break as well as large break LOCAs. This paper describes the market and regulatory drivers, the functional requirements for the new evaluation model (EM). An overview of the EM and key conclusions on its applicability to LOCA safety analysis are here summarized.