Application of GOTHIC8.0 3D Model to Simulate Heat Removal Process in Containment Safety Verification via Integral Test (CERT)

The purpose of this study is to establish a detailed three-dimensional (3D) model of containment safety verification via integral test (CERT) using the containment code GOTHIC 8.0. This paper presents the model construction and a typical CERT case for the model evaluation. In the typical CERT case, steam with high mass and energy is released to the test vessel to simulate the passive containment response during main steamline break (MSLB) accident. Heat removal process is accomplished primarily by absorption of energy by the gas volume and structures inside vessel, by condensation of steam on the inside shell surface, by heat conduction through the steel shell, and by evaporation of water film covered on the outer vessel shell surface. The main results of the typical CERT case are qualitatively compared with the results obtained from simulations with GOTHIC 8.0 code. From comparison, a verification of the code in terms of pressurization, temperature response, steam condensation and water film evaporation are carried out. The code analysis results are of significance on the research of thermal hydraulic phenomena which occur in the passive containment cooling system (PCS) during accidental sequences.