Preliminary analysis of irradiation effects on Clam after low fluence neutron irradiation

Full text of publication follows: For fusion application, the reduced activation ferritic/martensitic steels (RAFMs) are presently considered as the primary candidate structural material based upon their low residual radioactivity, resistance to void swelling, good thermal stress resistance, fabrication technologies etc.. While neutron irradiation to materials in fusion reactor will cause displacement damage and transmutation helium formation in materials, which make the hardening, embrittlement and swelling effects to material at temperature below 400 deg. C. So irradiation experiments and property tests before and after irradiation are very important issues for fusion material research. Research on a new version of RAFMs i.e. China Low Activation Martensitic steel (CLAM) was started five years ago at ASIPP (Institute of Plasma Physics, Chinese Academy of Sciences) under wide collaboration with other institutes and universities in China based on the results and experience on the other RAFMs, such as EUROFER97, F82H, JLF-1 and ORNL 9Cr-2WVTa, which were widely studied in the world. Neutron and ion irradiation experiments and analysis on CLAM are being or to be carried out under wide collaboration in China and overseas. To study the radiation-induced hardening for CLAM, the tensile properties of HEAT 0603A, HEAT 0408B and HEAT 0408D of CLAM had been tested before and after neutron irradiation to 0.02 dpa, experimented in High Flux Engineering Test Reactor (HFETR) in China. The specimens were irradiated at 250 deg. C with a fast fluence of 1.51*1019 n/cm2 (>1 MeV). The increase of ultimate strength and yield stress are both about 10 MPa. Besides, the effects of silicon on radiation-induced hardening were analyzed. And comparison of hardening for CLAM and other RAFMs under similar irradiation conditions were introduced and analyzed. (authors)