Data Analysis for RPV Life Management Studies of Temperature Measurements From Monitoring of Safety Injection Fluid in Refueling Water Storage Tank

Abstract

In Electricite´ de France (EDF), it’s used to taking as a conservative constant value for the temperature of Refueling Water Storage Tank (RWST) in the deterministic and probabilistic analyses for Reactor Pressure Vessel (RPV) life management. The water contained in this storage tank supplies Security Injection during accidental conditions, such as loss-of-coolant accident (LOCA), so the temperature of this water is a very important input parameter for fracture mechanics analyses. In the continuation of [1], the aim of our study is to evaluate the variability of this temperature. Since 1999, EDF has been collecting the RWST temperature for several sites and several nuclear plant units. Using statistical analyses, this study aims at first to identify the most important RPV exploitation life events that influence this temperature and, at secondly, to obtain statistical density distributions in order to describe its variability in the most realistic way possible.