Preliminary accident analyses of in-vessel LOCA and In-box LOCA for China helium-cooled ceramic breeder test blanket system

Highlights: • The update CN HCCB TBM cooling system has been investigated using RELAP. • The Steady state result is in good consistence with the Finite Element Method (FEM) results. • LOCA in TBM First Wall (FW) cooling pipe is investigated. • LOCA in the interspace between TBM and TBM shield is investigated. • The parametric analyses during In-box LOCA are investigated. - Abstract: The preliminary transient accident analysis has been carried out since 2005 for China Helium Cooled Ceramic Breeder Test Blanket Module (CN HCCB TBM) on ITER equatorial port #2. In this paper, the RELAP5 model is recreated according to the design of the CN HCCB 1 × 4 TBM and its cooling system, and two design basis accidents (In-Vessel Loss of Coolant Accident (LOCA) and In-Box LOCA) are investigated. The influences of different break sizes during these accidents are comprehensively analyzed. The analysis results can provide a reference for the following parameter optimization design of CN HCCB Test Blanket System (TBS).