HEAT REMOVAL DESIGN FOR A MODULAR SHIELDING HOUSE FOR KEEPING SPENT FUEL TRANSPORTABLE STORAGE CASKS IN AN INTERIM STORAGE FACILITY

OCL and NFT have developed the modular shielding house, which is one of forms for a storage building. In this study, the scale model testing and the thermo-fluid analysis considering both heat transfer and fluid flow have been performed in order to evaluate the heat removal performance of the modular shielding house precisely. As the result, the modular shielding house was confirmed to have the adequate heat removal ability and the heat removal evaluation method with a high degree of accuracy has been established for the modular shielding house. The following results are obtained from the thermal tests using the 1/4 scale model; The air temperature in the shielding house model goes up uniformly in the vertical direction and the significant stagnant air portion is not observed. The tests of total 7 cases were performed by changing parameters such as heat output, height of shielding house, area of air inlet and outlet. For all cases, measurement values of the exhaust air temperature were nearly agreed with calculation results using a air draft head calculation method used in stack design and it is concluded that this method can be applied for the heat removal design of the modular shielding house. The four analysis models were created for the scale test model to evaluate the effects of pressure drop of louvers and thermal radiation and mesh size. The model which has fine mesh for air layer adjacent to cask surface was verified to be adequate by comparing with scale test results. The thermo-fluid analysis results performed for the actual shielding house show that our proposed modular shielding house has the effective heat removal performance.