Progress of advanced material tokamak experiment (AMTEX) program on JFT-2M

Application testing of the low activation ferritic steel to plasma is in progress in the JFT-2M tokamak. The toroidal field ripple reduction with ferritic insertion between the vacuum vessel and the toroidal field coils (1st stage) was successfully demonstrated. So far, no deteriorating effects of ferritic boards (FBs) inside the vacuum vessel has been observed in the pre-testing on compatibility with plasma (2nd stage). The density limit was improved by more than a factor of 1.6 after boronization with inside FBs. Design and preparation works are in progress for the testing on compatibility with plasma (3rd stage), where inside wall of the vacuum vessel will be fully covered with ferritic steel.