Determination of the Optimal Surveillance Test Interval for Shutdown System Number 1

Abstract

Two probabilistic models focusing on the channel surveillance tests of the shutdown system number 1 (SDS1) in a CANDU nuclear power plant are proposed in this paper. The first one is a state transition model which is used to study the effect of surveillance test intervals on the unavailability and the probability of spurious trips. The second model is developed to examine the effect of the test interval on the core damage probability caused by both spurious trips and unavailable channels in the SDS1. The calculated core damage probabilities have clearly shown that there is an optimal test interval to provide the minimal probability of core damage. Therefore, the results are of significant importance in practice.