Discharge and poloidal magnetic field reconstruction in a ferritic first wall tokamak

A tokamak discharge with ferritic steel first wall was tried successfully. The Hitachi Tokamak HT-2 had a stainless steel SS304 vacuum vessel and modified to have a ferritic plate first wall for experiments to investigate the possibility of ferritic material usage in magnetic fusion devices. The achieved vacuum pressure was roughly identical with the stainless steel first wall or the original HT-2. About 1500 discharge tries clean up the ferritic plates to obtain normal discharges. We concluded that ferritic material vacuum vessel is possible for tokamaks