ABSTRACT
For example, Safety Analysis Report (SAR-1996, 1996) and Review of Safety Report (RSR-1997, 1997) of the Ignalina NPP concluded that closure of the gas gap between the pressure tube and graphite bore is one of the most important reactor operation lifetime criteria. Therefore there was performed a re-search for development of the gas gap existence criteria. The performance of probability analysis for gas-gap closure in Unit 2 is becoming more and more difficult because of the lack of statistical data. In last two years no measurements were taken in Unit 2 (shut down of Unit 1 was in 2004). The main objectives of this paper are
1. to update parameters’ estimates of graphite bore diameters dependence on burn-up function using Bayesian approach in two steps-primarily incorporating statistical data of Unit 1, then measurements of Unit 2. Perform analogous calculations to obtain updated pressure tube diameter’ dependence on burn-up function.
