SPES3 facility: RELAP5 simulations, from 65% power, of the DBE DVI line split break, BDBE EBT top line DEG break, Fukushima type SBO, for design support

This report has been issued in the frame of the ENEA and MSE research program on "Nuovo Nucleare da fissione". It is the deliverable D1 of the task LP2 of the work program PAR-2011 "Verifiche analitiche a supporto dell 'impianto SPES3, simulatore integrale di SMR". The document deals with the results of the RELAP5 simulations performed in support of the SPES3 facility design. In particular, three transients have been simulated: 1-inch equivalent DVI line split break, in design basis conditions, 4-inch equivalent EBT top line DEG break, in beyond design conditions, and SBO, Fukushima type, with further confirmation the plant configuration and safety systems are suitable to cope with such accidental conditions. Moreover, after the final mechanical design review of the EHRS, the results of 2-inch equivalent DVI line DEG break and SBO simulations have been compared to analogous transients with the originai EHRS configuration, showing the new design is suitable to transfer the required power.