Structural analysis of a two-component torus (TCT) hybrid reactor first wall

A double-wall concept is studied as a viable configuration for the first wall of a Two-Component Torus (TCT) hybrid reactor. The channel formed by the two walls permits coolant under pressure to circulate and reduce the first wall heat load. The first wall is also designed to perform the function of vacuum boundary. Thus, potential loads under consideration were pressure, temperature and irradiation induced swelling. General stability in the presence of a vacuum load was used as a criterion to arrive at initial dimensions. A free toroidal shell having the TCT radii was analyzed by the BOSOR4 shell-of-revolution digital code. This code uses the finite difference approach to structural model discretization and is capable of solving both the quasilinear and large displacement nonlinear stability eigenvalue problems. Using these approaches, the wall thickness and coolant channel spacing were derived. The BOSOR4 code was also used to check local wall stability between channels. A material selection of 316 stainless steel was made because its properties are both acceptable and relatively well established in the presence of irradiation. Fabrication processes are also well established for this material. The properties reviewed for failure mode assessment encompass creep, swelling, fatigue and crack growth. In determining the stress analysis, the simplifying assumption was made that the major radius of the torus was infinite. This permitted usage of an axisymmetric finite element program to solve for the stresses at the wall channel intersections. A review of potential failure modes confirmed that the first wall coolant was allowing a virtual infinite life condition