Neutron diffraction measurement of internal strain in the first Japanese ITER CS conductor sample

Hemmi, Tsutomu; Harjo, S.   ; Nunoya, Yoshihiko; Kajitani, Hideki; Koizumi, Norikiyo; Aizawa, Kazuya  ; Machiya, Shutaro*; Osamura, Kozo*

JAEA has responsibly to procure all ITER CS conductors. Several conductor samples was fabricated and tested. From the result of the cyclic testing in first conductor sample named JACS01 and second conductor sample named JACS02, the continuous linear degradation of the current sharing temperature () was observed. To investigate the degradation, the visual inspection of JACS01 right leg was performed. As a result, the large deflection at the lower loading side (LLS) in the high field zone (HFZ) was observed. The bending strain of the strands cannot be evaluated from the only deflection obtained by a visual inspection. To evaluate the strain of strands in the conductor sample quantitatively, the neutron diffraction measurement of JACS01 left leg was performed using the engineering materials diffractometer in J-PARC. From the result, the large bending strain at the LLS in the HFZ was observed. Therefore, the degraded position in the conductor sample can be determined.