Probabilistic Analysis of Creep-Induced SGTR for NPP

Abstract

Severe accident analysis is the technical basis of severe accident prevention and mitigation, and severe accident phenomenon analysis can provide important technical support for Level-2 Probabilistic Safety Analysis (L2 PSA) and severe accident management of NPP. This paper evaluates the probability of creep-induced steam generator tubes rupture (SGTR) which might lead to direct release of radioactive material to environment based on Risk-Oriented Accident Analysis Methodology (ROAAM). According to Larson-Miller creep failure model, the material parameters are provided first, then a two-loop NPP model is established with MAAP4 code to assess the temperature and pressure of the pipes for typical sequences, and eventually the probability of creep-induced SGTR phenomenon for typical sequences is calculated.