Scaling Design of Refrigerant-cooled Thermal-Hydraulic Integral Effect Test Facility for OPR1000

This study presents the design and preliminary verification of URILO-II, an experimental facility developed for integral effect test of nuclear safety technologies, while also providing a platform for thermal-hydraulic training through experimentation and observation. URILO-II was modeled on the OPR1000 power plant, the most commonly operated in Korea, scaled down to 1/8 height and 1/10 diameter. The refrigerant R134a was utilized to simulate two-phase flow of OPR1000 under 26.5 bar pressure. Scaling analysis indicated that similarity for the two-phase flow was secured, but distortion in single-phase flow heat transfer and temperature distribution was identified due to the refrigerant’s low single-phase heat transfer rate. Adjustments in power or flow rate were deemed necessary for accurate accident simulations. To check scaling design values, Comparative and CFD analyses were conducted, with resulted in an 8.5 % lower pressure drop. Further research will extend preliminary verification through system code analysis.