Preliminary irradiation test for new material selection on lifetime extension of beryllium reflector

Taguchi, Taketoshi ; Sozawa, Shizuo; Hanawa, Yoshio; Kitagishi, Shigeru  ; Tsuchiya, Kunihiko 

Beryllium has been utilized as a moderator and/or reflector in Japan Materials Testing Reactor (JMTR), because of nuclear properties of beryllium, low neutron capture and high neutron scattering cross sections. At present, it is necessary to exchange the beryllium frames within every fixed period; frames were exchanged five times up to the JMTR operation periods of 165th cycles, and amount of irradiated beryllium frames in JMTR is about 2 tons in the JMTR canal. In this study, preliminary irradiation test with two kinds of beryllium metals (S-200F and S-65C) was performed from 162nd to 165th operation cycles of JMTR as irradiation and PIE technique development for lifetime expansion of beryllium frames. The design study of irradiation capsule, development of dismount device of irradiation capsule and the high accuracy size measurement device were carried out. The results of PIEs such as tensile tests, metallurgical observation, and size change measurement were presented in this seminar.