EBR-II core damage potential for double pump faults

The simultaneous failure of the two main coolant pumps in the Experimental Breeder Reactor II (EBR-II) is an event that could conceivably pose a serious threat to reactor safety. Potential core damage due to double pump faults depends on the duration of the pump coastdowns and the response of the reactor shutdown system. Previous studies have investigated the thermal response of cores loaded with Mark-II fuel elements to specific loss-of-flow transients under protected and unprotected conditions. In the current investigation, a systematic study of core damage potential for a core predominantly loaded with Mark-III fuel elements was performed for postulated and idealized double pump faults under protected and unprotected conditions. The analysis was performed with the SASSYS liquid-metal reactor (LMR) systems analysis code. Determination of core damage potential is an important component of a level 1 probabilistic risk assessment of EBR-II. By combining accident sequence frequencies with associated core damage potential, the probability of core damage can be estimated. This paper summarizes the analysis of core damage potential for a group of accident sequences that are anticipated to be important contributors to core damage risk.