Transient analysis of a locked rotor/shaft seizure accident involving the EU-DEMO WCLL Breeding Blanket primary cooling circuits

The EU-DEMO Water-Cooled Lithium-Lead (WCLL) Breeding Blanket (BB) main subsystems to be cooled are the Breeder Zone (BZ) and First Wall (FW). Each subsystem will equipped with an independent Primary Heat Transfer System (PHTS). Within framework of EUROfusion Work Package research program, several accidents belonging category “Decrease in Coolant Flow Rate” were studied. activity was aimed at evaluating blanket primary cooling systems thermal-hydraulic performances during such transient conditions. A complete model including BB related PHTS circuits has been developed Sapienza University Rome. modified version RELAP5/Mod3.3 system code used perform calculations. simulation results showed that a locked rotor/shaft seizure BZ or FW coolant pump is most challenging scenario. behavior analyzed following this initiating event goal design improvement individuate need for preventive measures. influence loss off-site power on accident evolution also investigated. Moreover, management strategies have proposed different reactor components. Calculations demonstrate current appropriate cope these kinds scenarios.