JAEA studies on spent fuel pool severe accident, 2; Thermal-hydraulic research plan for evaluating capability of spray cooling

Nagatake, Taku ; Liu, W.; Koizumi, Yasuo; Takase, Kazuyuki; Yoshida, Hiroyuki  ; Nemoto, Yoshiyuki  ; Kaji, Yoshiyuki  

In the Fukushima Daiichi NPP accident, loss of cooling capabilities for spent fuel pool (SFP) occurred. As a result, a water level of the SFP decreased and it was concerned that the spent fuels were damaged. Therefore, safety measures for the SFP cooling are required in order to prevent the failure of the fuel rods. In one of the safety measures for the SFP, a portable spray system is considered as a device to cool the spent fuels. Then a capability of spray cooling have to be evaluated to validate the applicability of portable spray cooling systems as the safety measure for severe accident in the SFP. In this research project, the numerical simulation method for evaluating the capability of spray cooling has been developed. To develop this method, we mainly focus on the thermal-hydraulic behavior of two-phase flow generated by the spray cooling systems at a top and inside of the fuel assembly. In addition, we are planning to the spray cooling experiment in order to obtain a knowledge and validation data for numerical simulation method. In this presentation, current status of development of numerical simulation method and experimental plan of this research project will be shown and discussed.