Prospect of Spherical Tokamak towards a Power Reactor -Challenge towards the Lowest Aspect Ratio Tokamak- 5. Can We Obtain the Realistic Power Reactor in the ST Approach? 5.3 Neutron Shielding and Blanket Neutronics Design

Abstract

Considering the geometrical characteristics of tokamak reactors with low aspect ratio, a basic neutronics strategy was derived to construct an inboard structure mainly for neutron shielding and to produce enough tritium in the outboard blanket. The designs for optimal inboard shield were surveyed and the necessary thickness was estimated to make the neutron flux sufficiently low on the super-conducting magnet. In addition, the outer blanket designs were studied to attain a tritium breeding ratio (TBR) sufficiently large for a self-sustaining fusion reactor on the basis of advanced fusion reactor materials.