Feasibility of D3He/ST fusion power reactor

The prospects of D3He/ST fusion power reactors are explored and the design window of the reactor is specified. The D3He reactor needs no fuel-generating blanket and this permits a stabilizing wall to be located at a close distance from the core plasma for MHD stability; hence, the Troyon factor βN limit parameterized by C.P.C. Wong is employed (e.g. βN is 8.0–8.5 for κ=3 and the range of 1.5≤A≤1.8). The center column is fabricated from toroidal field (TF) coils without a center solenoid because of adopting a non-inductive current ramp-up scenario. The high temperature super-conductor (Bi2212/Ag/Ag) is chosen for TF coils; the operation temperature is 20 K; the current density of the conductor of the TF coil is about 110 MA/m2 at 18–23 T. The inboard radiation shield consists of low activation ferritic steel (F82H) and boric water, and its thickness is about 0.56 m for the lifetime (35 year) of the reactor. System analyses have indicated that the design window (which satisfies the constraints HHy2≤2, ne/nGW<1.1, and σTF≤800 MPa) is small and requires A>1.55, βt≤40%, and the first wall thermal loading Pw<1.25 MW/m2 to ensure the functional and structural reliabilities of the center column (i.e. TF coil system). Furthermore, HHy2=1.75–2.0, τp/τE=2.0–2.5, and Iφ=75–85 MA (in the first stability regime) and Iφ=57 MA (in the second stability regime) are needed to keep the stationary power balance of the core plasma.