Author(s)

V.A. Bui, T.N. Dinh & B.R. Sehgal

Abstract

Numerical modeling of heat-up and melting processes in internally heated debris bed and reactor vessel lower plenum V.A. Bui, T.N. Dinh, B.R. Sehgal Nuclear Power Safety Division, Royal Institute of Technology, Brinellvdgen 60, 10044 Stockholm, Sweden ABSTRACT The paper considers the two-dimensional thermal processes in internally heated oxidic debris beds in the lower plenum of a light water reactor vessel during the course of severe accidents with core meltdown and relocation. Heat transfer and phase change processes in debris beds and vessel lower head wall are investigated numerically with a particular emphasis on the dynamic characteristics of thermal transients in question. The main pur- pose of the work is to develop an appropriate modeling approach, which enables the analysis of complicated physical processes (involving dynamic changes of bed porosity, anisotropic heat transfer in remelting beds with internal energy sources) in complex domains of debris bed and vessel lowe

Keywords