Speaker
Hitoshi Tamura
(Department of Helical Plasma Research)
Description
The design activity of a conceptual design of a helical fusion reactor FFHR-d1 is progressing at the National Institute for Fusion Science. The superconducting magnet system of FFHR-d1 comprises one pair of helical coils, two sets of vertical field coils, and the coil support structure. The major and the minor radii of the helical coil are 5.6 m and 3.774 m, respectively. The magnetic field at the plasma center is 4.7 T. The coil support structure is designed from the perspective of the allowable stress of the material. Thus, it has apertures that are as large as possible to maintain in-vessel components. A continuous helical coil winding with a low temperature superconductor and a divertor made of tungsten and copper alloy with water cooling are considered for use in the reactor. These specifications comprised the basic option of FFHR-d1. In addition, there are several flexible design options. These options adopt new ideas that can solve certain issues in the basic option. The issues with the basic option include the winding method of the huge structure, high heat flux and neutron irradiation on the divertor, and the narrow radial build clearance. These alternative design proposals are treated as the challenging options. For example, a joint coil winding with a high temperature superconductor, a liquid metal divertor with molten tin, and an additional helical coil with a negative current flow that widens the distance between the plasma surface and the main helical coil are proposed. These proposals can be implemented by modifying the structural components of the basic option. In addition, design optimizations will be conducted by considering factors including mechanical soundness, magnetic field precision because of the deformation of the coils, an assembling/maintenance procedure, and a reduction in total weight via a finite element analysis and 3D model printing.
Co-authors
Akio Sagara
(Department of Helical Plasma Research, National Institute for Fusion Science, Toki-shi, Japan)
Hidetoshi Hashizume
(Graduate School of Engineering, Tohoku University, Sendai, Japan)
Hitoshi Tamura
(Department of Helical Plasma Research, National Institute for Fusion Science, Toki-shi, Japan)
Junichi Miyazawa
(Department of Helical Plasma Research, National Institute for Fusion Science, Toki-shi, Japan)
Nagato Yanagi
(Department of Helical Plasma Research, National Institute for Fusion Science, Toki-shi, Japan)
Satoshi Ito
(Graduate School of Engineering, Tohoku University, Sendai, Japan)
Takuya Goto
(Department of Helical Plasma Research, National Institute for Fusion Science, Toki-shi, Japan)
Teruya Tanaka
(Department of Helical Plasma Research, National Institute for Fusion Science, Toki-shi, Japan)
