Overview of the standard problems of the ATLAS facility

KAERI (Korea Atomic Energy Research Institute) has been operating an integral effect test facility, the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS), for transient and accident simulations of advanced Pressurized Water Reactors (PWRs). Using ATLAS, a high-quality Integral Effect Test (IET) database has been established for the major design basis accidents of the APR1400 (Advanced Power Reactor 1400 MWe) plant. Several standard problem exercises using the ATLAS database were performed to transfer the database to domestic and international nuclear industries and contribute to improving a safety analysis methodology for advanced PWRs. The ATLAS Standard Problem (ASP) exercises, e.g., two domestic standard problem (DSP) exercises and one International Standard Problem (ISP) exercise, aim at an effective utilization of the integral effect database obtained from ATLAS, the establishment of a cooperation framework among domestic and international nuclear industries, a better understanding of the thermal hydraulic phenomena, and an investigation into the possible limitation of the existing best-estimate safety analysis codes. Three kinds of Small Break Loss of Coolant Accidents (SBLOCAs) were determined as target scenarios by considering their technical importance and incorporating interests from participants. An overview of the ASP exercises is described in this paper.