Thermal Hydraulics Transient Analysis of Silicide Core Design of RSG-GAS Due to LOFA

Transient analysis for thermalhydraulic silicide core design has been carried out.LOFA is assumed to occur while the primary flow rate reached to the minimum value, the trip signal will be initiated by reactor protection system. The analysis is done by using EUREKA-2/RR program. The calculation model was developed by dividing the core into several channel groups according to the silicide radial peaking factors. The accident sequence has two important thermal-hydraulic behaviors from safety point of view. First, the even which occurs just after the reactor scram and the second is after natural circulation flaps opened. Analysis result show that the reactor scram takes place 2.95 sec after the accident is initiated. The fuel meat maximum temperature, fuel surface temperature and hot channel outlet coolant temperature each are 147.830c,142.390c and 77.610c, respectively,and the minimum DNBR and S, each are 1.16 and 3.94, respectively. The natural circulation flaps was opened at 67.82 second after the scram initiation. The fuel meat and cladding reached to the maximum temperature 132.060c and 131.210c respectively at 73.10 second after scram initiation. The maximum coolant outlet temperature reaches 78.360c at 70.40 second and the minimum DNBR and S, each are 1.74 and 9.63