Research on the influence of chemical reaction model over MCCI heat transfer process

Abstract

In the process of a severe accident that caused loss of heat removal capacity and subsequently led to reactor vessel failure, the Molten Core corium drops into cavity to Interact with Concrete (MCCI). It is essential for the safety analysis of nuclear power plants. The MCCI mechanism process is complicated and usually simplified into chemical reactions and heat-mass transfer in simulation. This paper analyzed a chemical equilibrium model and selected suitable substances attending chemical reactions, then investigated the relationship between chemical reactions and heat transfer. This model was compared via an ACE-L6 test, and the simulation results were matched well with the experiment and CORCON/VANESA code. Afterward, it was integrated to analyze the entire MCCI sequence of a PWR. The sensitivity analysis of chemical model parameters was performed. The results showed that the chemical reaction model has important influences on the MCCI heat-mass transfer process, especially at the early stage.