Validation of the SPACE Code Through Simulated Accident Scenarios in SMART-ITL: A Focus on Pressurizer Safety Valve Break and Safety Injection Line Break Concurrent with TLOSHR

Nuclear system analysis codes must demonstrate their capabilities in order to be licensed for usage in the design and safety analysis of nuclear power plant. The Safety and Performance Analysis CodE (SPACE) has been developed and approved to be used for licensing applications of Pressurized Water Reactors (PWRs). However, since new innovative designs such as SMART100, a 100 MWe system-integrated modular advanced reactor, incorporate inherent and passive safety features that are not used in conventional loop-type reactors, special models should be developed and validated to reflect the characteristics of the SMART-100 and obtain reliable predictions. A thermal-hydraulic integral effect test facility, SMART-ITL, was constructed to evaluate the system performance of SMART-100 and investigate the thermal-hydraulic phenomena that occur in the reactor systems and components under normal, abnormal, and emergency conditions. The experimental data also serves to validate the related thermal-hydraulic models of the safety analysis codes. This study presents a validation of the SPACE code, using the SMART-ITL facility, to evaluate its applicability for analyzing thermal hydraulics in integral reactors. Simulations were performed for two experimental test scenarios: pressurizer safety valve break and safety injection line break concurrent with total loss of secondary heat removal (TLOSHR). The validation results indicate that the SPACE code accurately predicted key thermal hydraulic behaviors, such as primary and secondary system pressures and temperatures. However, a slight underestimation of the RPV’s water level was observed, attributed mainly to the overestimation of the accumulated break flow due to inaccuracies in the two-phase critical flow models.