Research Plan on Evaluation of Spray Cooling Capability for Spent Fuel Pool

In the Fukushima Daiichi Nuclear Power Plant accident, loss of cooling capability for Spent Fuel Pool (SFP) occurred. As a result, the water level of the SFP decreased due to the evaporation by the decay heat and was concerned that the spent fuels were damaged. Therefore, safety measures for SFP cooling are required in order to prevent the failure of the spent fuels. A portable spray system is considered as one of the safety measures for SFPs. When the spray system is applied to SFPs, a capability of spray cooling has to be evaluated to validate the applicability of portable spray systems as the safety measure for severe accident in SFPs. Then we started the research project to evaluate the spray cooling capability for SFPs. In this research project, the numerical simulation code for evaluating the capability of spray cooling is being developed. To develop this method, we focus on thermal-hydraulic behaviors of two-phase flow, which affect the cooling capability, such as Counter Current Flow Limiting (CCFL) phenomenon. This paper the research plan for spray cooling is described.