Japanese activities in ITER transitional arrangements

The ITER transitional arrangements (ITA) is conducted by the International Team (IT) with supports from participant teams (PTs). The Japanese Participant Team (JA-PT) has contributed to the ITA by sharing a lot of technical tasks to verify feasibilities of fabrication and quality control method in procuring ITER equipments and facilities. For examples, trial fabrications of Nb3Sn strands have been performed by the JA-PT with four potential suppliers, and it has already been confirmed that one of the strands produced by a certain supplier meet the ITER requirements. All strands produced by other suppliers will be fully qualified by the end of 2005. The trial fabrications of jackets for the central solenoid (CS), structural material for toroidal field coil, the partial mock-ups of the vacuum vessel (VV) and the shield blanket module are also ongoing to verify the feasibility of fabrications and quality inspections. Furthermore, the JA-PT has made several technical developments on neutral beam (NB) system to improve reliability in high voltage (1 MV) insulation and in stable high current density operations over a long period. Design of equatorial EC launcher and some techniques towards reliable steady-state EC operation have been developed. The paper also describes other activities to confirm validity of the present design.