3D-CFD&FEMを用いたPTS時のRPV構造健全性評価と保全最適化
概要
The structural integrity of reactor pressure vessels (RPVs) is an important issue in the field of nuclear power plants. The RPV contains a reactor core, which is impossible to substitute. The pressurized thermal shock (PTS) loading is a critical issue in assessing the safety of RPV. The most severe situation takes places during cold water injection in the cold legs when the emergency core cooling system (ECCS) is operated due to LOCA. Under these circumstances, the PTS loading may lead the RPV to brittle fracture due to neutron irradiation. In the present study, we focus on the perspective of an RPV maintenance. A reference design of a four-loop RPV is applied, and five different cases of ECCS water injection proposals which are symmetric or asymmetric situations are considered. For each case, 3D-CFD and FEM analysis were performed to provide the SIF (KI) as a function of the position of RPV. By comparing KI values in RPV for these cases, the proposal is finally discussed, which will provide a deep insight on more appropriate maintenance of an RPV.
