The effects of grain size and helium accumulation on radiation hardening and loss of ductility of pure copper for ITER application

This paper focuses on the effect of the grain size and high rate of helium accumulation on radiation resistance of pure copper for ITER applications. The paper presents the results of irradiation of three different pure copper grades in the dose range of 0.001-0.1 dpa at 80degreesC in the SM-2 reactor. Irradiation at temperatures of 80degreesC causes hardening of pure copper. The uniform elongation of samples of all pure copper grades is rather low, the total elongation after irradiation amounts to 10-30%. It is shown that hardening and loss of ductility of pure copper irradiated in the SM-2 to 10(-3)-10(-1) dpa at 80degreesC are determined mainly by two factors: irradiation dose and grain size. Accumulation of high helium concentrations does not have an essential effect on embrittlement. (C) 2003 Elsevier B.V. All rights reserved.