Conceptual Design of Magnets with CIC Conductors for LHD-type Reactors FFHR2m

LHD-type reactors have attractive features for fusion power plants, such as no requirement of a current drive and a wide space between the helical coils for the maintenance of in-vessel components. One disadvantage was considered the requirment of a large major radius to attain the self-ignition condition with a sufficient space for blankets. According to the recent reactor studies based on experimental results in LHD, the major radius of plasma is set at 14 to 17 m with the central toroidal field of 6 to 4 T. The stored magnetic energy is estimated at 120 to 130 GJ. Both the major radius and the magnetic energy are about three times as large as those for ITER. We intend to summarize the requirements for superconducting magnets of the LHD-type reactors and propose a conceptual design of the magnets with cable-in-conduit (CIC) conductors based on the technology for ITER

Fuel Particle Balance Study in FFHR DEMO Reactor

Tritium particle balance in the FFHR DEMO reactor is investigated with consideration of the fueling efficiency by pellet injection system, retention loss in a vacuum vessel and permeation loss from the fuel processing system. In order to satisfy the fuel balance and the tritium safety management, it was necessary to suppress the tritium retention rate to be 10?5 and the DFs in the tritium cycle systems to above 107 with the tritium breeding ratio of 1.08. The processing throughput for the tritium processing system is estimated to be about 400 mol/h, which is almost same as the throughput of the fuel stream for the ITER. Therefore, the tritium processing system for vacuum exhaust gas for the DEMO will not be necessary to improve the system for the ITER further. On the other hands, the significant development of the tritium processing system for the effluent disposal and the waste materials from the safety aspect and the social acceptance will be required toward the DEMO reactor