Accident analyses of selected postulated events for safety assessment of Indian LLCB TBS in ITER

Abstract The Lead Lithium cooled Ceramic Breeder (LLCB) TBM) is being developed by India for testing in ITER machine. Thermal hydraulic safety analyses are the essential part of engineering design of LLCB Test Blanket System (TBS) for safe operation in ITER environment. The current work involves thermal hydraulic analyses and preliminary results of selected accident scenarios involving ancillary systems, the First Wall Helium Cooling System (FWHCS) and the Lead Lithium Cooling System (LLCS). A modified version of RELAP/MOD4.0 safety analysis code is used to simulate the transient scenarios. A detailed nodalization is carried out with all the major components in FWHCS and LLCS along with associated heat structures and connected confinement volumes. The accident analysis is performed for the scenarios including the ex-vessel Loss Of Coolant Accident (LOCA) in FWHCS into Port Interspace, Loss Of Fluid Accident (LOFA) and Loss Of Heat Sink (LOHS) accident in FWHCS and LLCS. Transient analyses results of each accident case are reported here and it is found that current design meets most of the thermal hydraulic safety requirements while changes in the design are proposed for certain accident scenarios.