Novel Solution for the Problem of Neutron Streaming Through Inboard Assembly Gaps of ARIES Tokamak Power Plants

In ARIES tokamak designs, there are assembly gaps between adjacent blanket and shield modules. These gaps allow increased levels of radiation to reach outer components. Three-dimensional models of the tokamak were used to analyze the effect of radiation streaming through both straight and stepped gaps of 1 cm and 2 cm wide. We proposed a novel idea of inserting a WC shield block within the double step region to further attenuate the streaming neutrons. Radiation damage parameters were calculated for the inboard components including the first wall, shield, manifolds, vacuum vessel, and magnet. Our results show that straight gaps allow too much radiation to reach the inboard components, resulting in large peaking in radiation damage parameters. The double stepped gap with WC shield block show reduced peaking and are effective at protecting the vacuum vessel and magnet.