DESIGN OF A STEADY-STATE TOKAMAK DEVICE WITH SUPERCONDUCTING COILS FOR A VOLUMETRIC NEUTRON SOURCE

We designed a volumetric neutron source for testing large-scale blanke t components, based on a steady-state tokamak device with superconduct ing coils. It is found that a neutron flux of approximately 1.0 MW m(- 2) is available in the medium-size device (R = 4.5 m, a = 1.0 m, kappa = 1.8, I-p = 5.6 MA) under the conditions of H similar to 2 and beta( N) similar to 3 with a neutral beam injection (NBI) power of about 60 MW. We demonstrate the controllability of the current profiles require d for high-beta plasma up to beta(N) = 3-3.8 with the combination of b ootstrap current and NB-driven current (E-b = 1.0 MeV). If an advanced performance scenario such as a reversed shear configuration is availa ble, a neutron flux of 1.4 MW m(-2) is achievable. We install the bree ding blanket of Li-Pb only at outboard and upper regions, and find tha t a local tritium breeding ratio (TBR) of 1.5 is achievable and a net TBR of 0.8 could be available. The analysis of shielding materials at the inboard region shows that the proper combination of tungsten, stee l and boric water yields a reduction of the nuclear irradiation of TF coil by a factor of approximately 10. (C) 1998 Elsevier Science S.A. A ll rights reserved.