Numerical Study on Radiative Heat Transfer Performance of ACP100 Passvie Containment Air Cooling System

Abstract

Passive containment Air cooling System (PAS) is an important Engineering Safety Feature of the small modular pressurized water reactor ACP100, designed by China National Nuclear Corporation (CNNC). The function of the PAS for ACP100 is to remove the heat inside the containment continuously through the natural circulation of air cooling during hypothetical accidents in order to keep the internal temperature and pressure of the containment within the design limits. Therefore, the heat transfer performance of the PAS has been widely concerned. Related heat transfer phenomena include conductive heat transfer, convective heat transfer, and radiative heat transfer. The radiative heat transfer has played an important role on the overall heat transfer performance of the PAS. In this paper, ANSYS Fluent 19.0 was used to build a CFD model for the PAS, investigating the effects of wall emissivity of the steel shell and the concrete shell on radiative heat transfer performance of the PAS under accident scenarios at steady state. The numerical study results show that 874.96 kW increase in the radiative heat transfer power when wall emissivity of the steel shell is from 0 to 1 at wall emissivity of the concrete shell of 0.92 at steady state, the proportion of the radiative heat transfer in the total heat transfer increases from 0% to 42.41%. 712.51 kW increase in the radiative heat transfer power when wall emissivity of the concrete shell is from 0 to 1 at wall emissivity of the steel shell of 0.84 at steady state, the proportion of the radiative heat transfer in the total heat transfer increases from 9.44% to 41.58%. Therefore, wall emissivity of the steel shell and the concrete shell has a significant influence on radiative heat transfer performance of the PAS. The above numerical study results can provide some necessary data reference and support for the PAS design and optimization, which has some practical engineering significance.