Experimental Study of Small and Medium Break LOCA in the TTL-2 Thermo-Hydraulic Test Loop and Its Modeling with RELAP5/MOD3.2 Code

Small and medium break LOCA accidents at low pressure and under low velocity conditions have been studied in the TTL-2 Thermo-hydraulic Test Loop, experimentally. TTL-2 is a thermal hydraulic test facility which is designed and constructed in NSTRI to study thermal hydraulic parameters under normal operational and accident conditions of nuclear research reactors. A nodalization has been developed for the TTL-2 and experimental results have been compared with RELAP5/MOD3.2 results. The considered accidents are a 25% and 50% cold leg break without emergency core cooling systems. Results show good agreement between experiments and RELAP5/MOD3.2 results. This research provides experimental data for evaluation of thermo hydraulic codes for nuclear research reactors, and veri es that RELAP5/MOD3.2 has a good capability to estimate the thermal hydraulic behavior of low pressure and low velocity thermal hydraulic systems, such as research reactors under steady state and transient conditions.