Material irradiation conditions for the IFMIF medium flux test module

The International Fusion Materials Irradiation Facility (IFMIF) is an accelerator driven neutron source, which is designed to perform material irradiations at conditions very close to that of future fusion reactors up to the anticipated lifetime of structural materials. Besides irradiation of material samples in the high flux test module, in situ creep-fatigue tests for structural materials in the creep-fatigue test module (CFTM) and tritium release experiments for breeder blanket materials in the tritium release module (TRM) are foreseen in the medium flux test module (MFTM) of IFMIF. The present study is devoted to the evaluation of the creep-fatigue specimens and beryllium irradiation conditions in the MFTM of IFMIF. It is demonstrated that maximum displacement damage rate in the CFTM is about 13 dpa/fpy. The analysis shows that the TRM can closely meet fusion-typical He and dpa production rates in Be, while the T-production is somewhat above fusion conditions for the present test module design. Removing the CFTM and shifting of the whole TRM upstream increases the damage rate to about 60% of that for a fusion reactor and provides tritium and helium production rates comparable with fusion. In addition, the important He/T ratio nicely fits the fusion relevant value after one year of irradiation in the IFMIF TRM.