Development of Initial Input Parameters for a Probabilistic Pipe Rupture Assessment Code for Nuclear Reactor Coolant Pressure Boundary Leak-Before-Break Analyses

The U.S. Nuclear Regulatory Commission (NRC) and the Electric Power Research Institute (EPRI) entered into a cooperative agreement to develop a modular computer code for determining the probability of rupture of reactor coolant pressure boundary piping. The goal of xLPR project (Extremely Low Probability of Rupture), as it is known, is to develop a flexible modular code that satisfies the assessment methodology in the NRC Standard Review Plan (SRP) 3.6.3 leak-before-break analysis. The NRC SRP 3.6.3 provides guidance on satisfying Title 10 of the Code of Federal Regulations Part 50 (10 CFR Part 50) Appendix A, General Design Criteria 4 that requires primary system pressure piping to exhibit an extremely low probability of rupture. The initial phase of the xLPR project is the Pilot Study where the base structure of the code will be developed and tested on a known case. The Pilot Study version of the xLPR code consists of an alpha version where proxy modules and inputs are used and a beta version where the state-of-the art modules and inputs are used. This paper will discuss the input parameters used for the alpha xLPR code.