LBLOCA Analyses for 4.5% Power Uprating using KREM

KREM is a best-estimate LBLOCA (Large Break Loss-Of-Coolant Accident) evaluation model, which was developed to comply with Regulatory Guide 1.157, 10 CFR 50.46 and their equivalents in Korea. A licensing LBLOCA analysis using KREM was performed for the first time to assess the ECCS (Emergency Core Cooling System) performance of Kori-3/4 and Yonggwang-1/2 under the condition of power uprating by 4.5%. A break spectrum analysis for 100%, 80%, and 60% DECLG (Double Ended Cold Leg Guillotine) breaks was performed and eighty SRS (Simple Random Sampling) calculations were conducted on the limiting break size. Another analysis with the same procedure was done for the current operating conditions to evaluate the effect of 4.5% power uprating including 1.5% TDF (Thermal Design Flow) reduction on LBLOCA consequences