Neutron irradiation response of explosion-welded CuCrZr/316LN joints for ITER application

摘要

Explosion-welded CuCrZr/316LN joints, which serve as key joining components in enhanced-heat-flux type first wall panels of ITER, have been neutron irradiated in the BR2 reactor (Belgium) at 190 degrees C, up to 0.3 dpa. The joints have maintained good structural integrity after irradiation and were free of void swelling. Radiation defects featuring black-spot contrasts were produced on both sides of the CuCrZr/316LN interface. They were on the order of 10(22) m(-3) in number density and all less than 4 nm in average size. Radiation-enhanced diffusion might have favoured the dissolution of interlayers which were characteristic of pristine CuCrZr/316LN joints, and accelerated the diffusion of key elements (e.g. Cu, Fe) across the interface. The joint interface experienced an increase of Vickers hardness by similar to 21% (Delta H-v = 48) after neutron irradiation. Heat treatments of 500 degrees C/1 h resulted in moderate softening of the interface, while 800 degrees C/1 h gave rise to a complete elimination of irradiation-induced hardening effect, respectively.