Deterministic safety analysis of the reference accidental sequence for the European HCPB TBM system

In order to investigate the accidental behavior of the helium cooled test blanket module and its auxiliary systems, a particular sequence has been selected for the deterministic analyses in the frame of the EFDA licensing task for ITER. This sequence starts from an ex-vessel loss of coolant with simultaneous assumed failure of the plasma shutdown system. This paper presents the study of this sequence with the use of various assumptions and code-dependent modeling (RELAP5, MELCOR and ANSYS). Two different variants of the sequence are analyzed depending on the assumption of the failure of water-cooled component of ITER. The resulting transients show the effect of the exposure of the Be pebble beds on air and on a mixture of air and steam.