Experimental Study in Cooling Rate by Containment Spay

Abstract In case of loss of coolant accident, temperature and pressure in the containment would rise due to evaporation of coolant. Besides, radioactive aerosol and gas could possibly release to the containment in case of severe accident. Containment spray system is designed to cool it down, reduce its pressure and remove airborne radioactive material. According to NUREG 1465, 95% of released fission product exists in form of aerosol. Therefore, one experimental apparatus for typical China three loop PWR was built to investigate the above phenomenon. It consists of 4 parts: 1) spray vessel, which simulates reactor containment; 2) Spray system; 3) measurement system including temperature, pressure and flow rate; 4) Water tank, which stores and provides spray water. The spray vessel is 2.0m high with an internal diameter of 1.0m. There are 9 temperature sensors inside the spray vessel. The maximal design pressure of the vessel is 0.8MPa and maximal design temperature is 180°C. The spray tank is 1.0m high with an internal diameter of 1.0m. Temperature is the key factor that influence the behavior of aerosol, so the cooling rate experiment was conducted before the aerosol removal coefficient experiment. In this paper, experiments were conducted to obtain cooling rate by containment spay, which was the basis for aerosol removal coefficient experiment. Temperature distribution of spray vessel during the spray was obtained and cooling down rate was measured. Results show that spray flow rate and spray water temperature are the main parameters that determines cooling down rate. In future, aerosol spray removal coefficient will be obtained.