Thermalhydraulic analysis of the silicide core of MPR-30 under the closed isolation valve condition

The RSG-GAS fuel element conversion program from oxide with 2.96 gr U/cm gr3, fuel loading, is needed accidents analyzed from many kinds of view, not except from thermal hydraulic aspect. The safety assurance was done by various thermal hydraulic analyses and employed based on design basic accident sequence on RSG-GAS safety analysis report, chapter 15. The purpose of this accident analysis is to obtain the thermal hydraulic characteristic core in the transient condition due to inadvertent closure of the primary isolation valve. Using EUREKA-2/RR computer code, this accident did analysis in the worst case condition on hot channel. this analysis needed coast down pump profile. the curve is made by assumption on adequately high flow through the core (16% of the rated value) is still available 40s after scram and become zero at 70s after scram. By superposition between closure of the primary isolation valve and the reduction of the pump flow rate, the results show that due to the flow reduction to the core before free convection occurred, the valve closure accident will be covered safety