CHF Experiment for Heater Inclination Angle and Material Effect for Downward Facing Surface

For sever accident mitigation, In-Vessel Retention through External Reactor Vessel Cooling (IVR-ERVC) strategy is used to remove the decay heat of the molten corium. The Critical Heat Flux (CHF) is one of the most important criteria in determining the success of the IVR-ERVC strategy. Amount of molten corium is depend on accident scenario, and hence maximum heat flux location is also changed by it. Therefore, to assess success of the IVR-ERVC, the location-specific CHF database is required. In this study, the CHF experiments were conducted to evaluate the effect of heater inclination angle and material. For the SUS304 heater, 30 °, 60 ° and 90 ° inclination angle experiments were conducted. For the SA508, 60 ° and 90 ° inclination angle experiments were conducted. Through the experiments, the lower heater inclination angle made the lower CHF value. The reason was the vapor escaping time was getting longer for the lower inclination angle. The CHF of SA508 heater was higher than one of SUS304 for all inclination angle, because the oxidized SA508 surface had better surface wettability and it enhanced the CHF.