Abstract ITER Test Blanket Module (TBM) which will be the act-alike module corresponding to DEMO blanket is aimed to verify the capability of tritium self-sufficiency and the extraction of high heat using tritium breeding concepts for ITER missions. Conceptual design of Korea Helium-Cooled Solid Breeder (HCSB) TBM, one of two concepts that Korea has proposed, has been performed including performance analyses. In this paper, the results of preliminary safety analyses of Korea HCSB TBM are described. In-vessel, in-box and ex-vessel loss of coolant accidents are selected as three reference accidental scenarios for the TBM. Each scenario is modeled and computed by RELAP5/MOD3.2, developed for thermo-hydraulic transient simulation of light water reactor coolant systems. The results show the robustness of the design from the safety perspective.