Major outcomes through recent ROSA/LSTF experiments and future plans

Takeda, Takeshi ; Wada, Yuki   ; Shibamoto, Yasuteru 

Many experiments have been conducted on accidents and transients of pressurized water reactor (PWR) employing the rig of safety assessment/large-scale test facility (ROSA/LSTF). Major results of the related integral effect tests with the LSTF were reviewed to experimentally identify thermal-hydraulic phenomena involved, regarding the PWR accident sequences in accordance with the new regulatory requirements for the Japanese light-water nuclear power plants. Key results of the recent integral effect tests utilizing the LSTF and future plans were presented relevant to multiple steam generator tube rupture accident with recovery operation, small-break loss-of-coolant accident (LOCA) with accident management measure on core exit temperature reliability, and small-break LOCA with thermal stratification under cold water injection from emergency core cooling system into cold legs.