Comparative Analysis of Loss of Coolant Accidents for GEN-III PWRs Based on ACME and ATLAS Facilities

Abstract ISP-51 and ISP-50 are two recent international cooperation projects organized by OECD/NEA, with the aim of comparing and evaluating the capability of best estimate system codes. ISP-51, led by HUST, is based on ACME (Advanced Core Cooling System Mechanism Experiment) facility scaled from the CAP1400 in China. ISP-50, led by the KAERI, is based on ATLAS (Advanced Thermal-Hydraulic Test Loop for Accident Simulation) facility scaled from the APR1400 in Korea. Both ISPs simulated Loss of Coolant Accident (LOCA) scenarios in the passive thermal-hydraulic facilities and followed the international ISPs practice of conducting blind test and open test. ISP-51 aimed to simulate CAP22 (a small 2-inch break at the cold leg and a failure of one of the four ADS4 valves on the non-PZR side) for the open phase, and CAP16 (a double ended break of direct vessel injection) for the blind phase. ISP-50 aimed to simulate a 50% direct vessel injection line break accident. Both ISPs are based on the LOCA transients on integral test facilities mocked from the representing GEN-III PWRs with similar power level and passive safety features. Since CAP1400 and APR1400 are both of GEN-III PWRs with passive safety features and similar power level, it would be of interest to study these two ISPs, comparatively, by cross-checking and analyzing the prototypic reactors and test facility. This study further enhances the understanding of typical GEN-III PWR technologies, provides us insightful view about the overall design characteristics and passive safety features.