Modeling of Steam Explosion in Partially Flooded PWR Reactor Cavity

Abstract

When the hot molten core comes into contact with the water in the reactor cavity a steam explosion can occur. The steam explosion might be triggered during some scenarios of severe nuclear reactor accidents, when extremely hot molten nuclear fuel interacts with the coolant water. A highly energetic steam explosion in a nuclear power plant could cause the containment failure and the release of radioactive fission products to the environment. The purpose of the performed analysis is to provide a first estimation of the expected pressure loadings on the typical PWR cavity structures during a steam explosion. To achieve this, the fit-for-purpose steam explosion model is proposed, followed by a Computational Fluid Dynamics (CFD) analysis. In the present work two steam explosion scenarios in the partially flooded Pressurized Water Reactor (PWR) cavity were simulated with the general purpose code CFX-5 [1] to estimate pressure loadings on cavity walls.