Assessment of RELAP5/MOD3/CANDU+ to Wolsung-1 D2O leakage event

In order to evaluate the integrated performance of RELAP5/MOD3/CANDU+ for CANDU operational transient analysis, we assesed the code to the D2O leakage event occurred at Wolsung-I, 600 MW(e) CANDU reactor, on Oct. 20, '94. D2O leakage event was initiated by stuck opening of liquid relief valve No.4 in primary coolant pressure and level control system. Assessment calculation was performed for the plant transients up to 1000 seconds after the initiating event. Calculation results are compared with those measured in primary heat transport system, pressure and inventory control system and boiler secondary system. Comparison with the plant trip log shows that the RELAP5/CANDU+ is able to simulate the plant transients properly, from which we can conclude that the RELAP5/CANDU+ is validated for application to CANDU operational transient analysis. CANDU specific models used in the assessment are fuel bundle heat transfer model, decay heat model and MOV(Motor Operated Valve) model