Application of Bayes Method in Evaluation of Rop/nop Trip Setpoint

Abstract

This paper provides an overview of a Bayesian statistical framework (SF) and software developed under a research project initiated by the Canadian Nuclear Safety Commission (CNSC) to enhance the capability for regulatory independent evaluation of effectiveness of ROP/NOP installed trip setpoint within a risk-informed decision making (RIDM) process.

The Bayesian SF has been designed to estimate the functional failure distributions for a ROP/NOP system with fixed design control variables (number of detectors, location of detectors and value of trip setpoint). Specifically, the Bayesian SF should answer the question: “What is the estimated frequency of NOP system (functional) failure and the uncertainty around that estimate?”