Technical development for in-pile IASCC growth tests by using a 0.5T-CT specimen in JMTR

Chimi, Yasuhiro; Shibata, Akira ; Ise, Hideo; Kasahara, Shigeki; Kawaguchi, Yoshihiko*; Nakano, Junichi; Omi, Masao; Nishiyama, Yutaka 

In order to load a large specimen of 0.5T-CT up to a high stress intensity factor of 30 MPa, we have adopted a lever type loading unit for in-pile irradiation-assisted stress corrosion crack (IASCC) growth tests in the Japan Materials Testing Reactor (JMTR). In this unit, the applied load is generated by shrinking a bellows with lower inner gas pressure than surrounding water pressure and enlarged by leverage. The crack length of the specimen is monitored by potential drop method (PDM) using mineral insulator (MI) cables. In this paper, technical concerns of the in-pile crack growth test unit, especially the estimation procedure of applied load to the specimen inside the irradiation capsule and the evaluation of precision of the PDM signals are presented.