Research and development of helical systems have been persistently continued. New large devices using superconducting magnets, LHD in Japan and W-7X in Germany, are under construction. These aggressive programs accelerate several design studies of helical-type reactors, because of the main advantage of current-less steady operation, as promising alternatives for Demo reactors. A reference design of Force Free Helical Reactor (FTHR) is presented to discuss Demo relevant engineering issues in the concept definition phase. The main feature of FTHR is force-free-like configuration of helical coils, which makes it possible to simplify the coil supporting structure and to use high magnetic field instead of high plasma beta. The other feature is the selection of molten-salt Flibe as a self-cooling tritium breeder from the main reason of safety. Collaboration works based on the LHD project have made great progress in the reactor studies by focusing on engineering aspects of the high magnetic field and Flibe system design.