MATERIAL CONSTITUTIVE MODELING OF NUCLEAR PRESSURE VESSEL STEEL FOR IVR-ERVC SIMULATION

Abstract

The lower head of the nuclear power plant reactor pressure vessel (RPV) can be subjected to severe thermal and pressure loads during the event of a core meltdown accident. As effective accident management strategy, IVR-ERVC (In-Vessel Retention of molten corium through External Reactor Vessel Cooling) strategy is introduced to reduce the possibility of a reactor containment failure by terminating the severe accident progress inside a reactor. In this case, the mechanical behavior of the reactor vessel lower head is of importance both in severe accident assessment and the assessment of accident mitigation strategies. This paper proposed material constitutive model, which is extended from constitutive model of Takahashi [1]. The proposed model can predict stress under large range of temperature and strain rate, which in turn can be used to predict material deformation under IVR-ERVC strategy.