Approaches to radiative heat transfer simulation in a cavity above melt

Abstract

The article presents a description of the THERA module, which allows the calculation of radiative heat transfer in the cavity above the melt in the complex geometry with the presence of participating medium in relation to the simulation of severe accidents at nuclear power plants with VVER type reactor. The net-radiation method is implemented in the module as a basic method for calculating radiative heat transfer; the radiation properties of gases are considered using the SLWSGG model. The results of THERA cross-verification on test tasks are presented. The paper presents the results of THERA simulation of radiative heat transfer from the corium surface to the reactor shaft structures at a nuclear power plant with a VVER – 1000 reactor as part of the analysis of the ex-vessel stage of a severe accident in axisymmetric and realistic non-axisymmetric forms.