Transient analyses for LBE cooled accelerator-driven system by RELAP5 code

Sugawara, Takanori; Nishihara, Kenji; Tsujimoto, Kazufumi

no journal, , 

It is supposed that an Accelerator-Driven System (ADS) is safer than conventional critical reactors since the ADS is driven by the external neutron source in the subcritical state. In this study, the transient analyses for the lead-bismuth eutectic (LBE) cooled ADS proposed by JAEA were performed by using the RELAP5/mod3.2 code to investigate the possibility of the core damage. In this research, three accidents; the protected loss of heat sink, the protected overcooling and the unprotected loss of flow were considered as the typical ADS accidents. Through these calculations, it was confirmed that all calculation results except the protected loss of heat sink satisfied the no-damage criteria. In the protected loss of heat sink, if the PRACS (Primary Reactor Auxiliary Cooling System) would not operate correctly, the cladding tube temperature would reach at its melting temperature after 18-21 hours although the calculation condition was very conservative. The transients for the beam trip were also calculated to derive the temperature changes at the important components such as the beam window, the cladding tube and the reactor vessel. These results will be employed for the lifetime estimation of these components.