APPLICATION OF SIMPLIFIED CONDENSATION MODEL TO PWR LBLOCA TRANSIENT ANALYSIS WITH TRAC-PF1 CODE

In the system analyses of a large-break loss-of-coolant accident (LBLO CA) of pressurized water reactors (PWRs), the TRAC-PF1 code predicted an unrealistic depressurization and required much computational time d ue to the problem of the condensation model. To eliminate the unrealis tic depressurization, the TRAC-PF1 code was improved using a simplifie d condensation model that determined the total condensation rate at co ld leg. Through the assessment calculations for CCTF, UPTF and LOFT te sts,it was confirmed that the simplified model could eliminate the unr ealistic depressurization and reduce the computational time. It was al so confirmed that the model could improve the accuracy of the system c alculation for the core inlet how rate and clad temperature as the res ult of the elimination of the unrealistic depressurization. It has bee n concluded that the simplified condensation model is useful for the s ystem calculation of the PWR LBLOCA.