Nuclear responses in IFMIF creep-fatigue testing machine

The International Fusion Materials Irradiation Facility (IFMIF) is an intense high-energy neutron source dedicated to the development and qualification of materials for the first generation of fusion reactors. The target facility will consist of a high flux test module for irradiating material samples to very high doses and a medium flux test module (MFTM) for conducting various experiments including the in situ creep-fatigue tests for structural materials. As it is recognized in the materials community, in situ creep-fatigue tests provide a more realistic estimate of the structural material fatigue lifetime under irradiation than postirradiation tests. The present study is devoted to the detailed evaluation of the nuclear environment at the creep-fatigue machines (CFM), in order to assess the radiation dose and heat deposition rates imposed to their components. Neutron transport calculations were performed using McDeLicious-05 code and updated global geometry model of IFMIF. The displacement damage rate induced by neutrons and heat deposition induced by neutrons and gammas are sufficiently low for metals, but could result in the damage of polymer materials used for electro-mechanical parts of the CFM. The material selection and the ways of handling the radiation loads in the sensitive parts of the machine are discussed.