抄録
After TMI and Chernobyl accidents, many efforts have been made to enhance the nuclear safety with passive features. Among such passive features, the passive containment cooling system has been suggested. In case of a Loss of Coolant Accident (LOCA) occurred, Passive Containment Cooling System (PCCS) cools the core decay heat. The objective of this experimental study is to clarify the heat transfer characteristics of PCCS on a vertical pipe. In order to calculate overall heat transfer coefficient between the cooling water and atmosphere, cooling water flow rate, cooling water temperature and gas temperature are measured. The influence of air concentration is clarified in the range of 0.1 to 25% of the air concentration at 0.4MPa(abs) of the system pressure. It is confirmed that decreasing of the heat transfer coefficient is affected by increasing of the air concentration.
