Design on Film Condensation Heat Transfer Enhancement in PCCS

The passive containment coolant system (PCCS) will remove energy in containment during a nuclear reactor accident, preventing containment form losing efficacy because of high temperature and pressure. In this paper, to improve heat transfer efficiency, it was assumed that several barrier rings and a droplet collector were installed in the containment. By reducing the liquid film thickness, disturbing the non-condensable gas layer, and using the higher heat transfer efficiency in the turbulence flow, the total thermal resistance was reduced and the heating efficiency was improved. Taking AP1000 as an example, the heat transfer efficiencies in containment in two cases with and without the new facility were analyzed with the GDLM model. The results show that barrier rings and droplet collector could decrease film thickness, raise heat flow and enhance heat transfer efficiency.