CAREM-25 accident analysis

This paper describes the response of the CAREM reactor prototype, CAREM-25, and its safety systems to representative accidental initiating events. A nodalization of the primary circuit including the steam generators was developed for RELAP5 and RETRAN02 codes to perform the accident analysis. Also a simplified two zone non-equilibrium model was developed to calculate long term reactor behavior. Secondary Shutdown, Residual Heat Removal and Emergency Injection systems were also modeled in detail. The reactor steady state was calculated at full power. The results agree quite well with design values, and this condition was used as reference for the accident analysis. Several initiating events were considered for the accident analysis. They were grouped into Reactivity Insertion, Loss of Heat Sink (LOHS) and Loss of Coolant Accidents (LOCA). As there are no primary pumps, Total Loss of Flow Accident (LOFA) is not applicable in this case. Results show that the design requirements are verified and the reactor reaches a safe condition, without need of active intervention. As a general conclusion, it could be said, that due to the large coolant inventory in the primary circuit, the system has a large thermal inertia and long response time in the event of transients or severe accidents. (author)