AbstractThe TITAN-II reactor is a compact, high-neutron-wall-loading (18 MW/m2) design. The TITAN-II fusion power core (FPC) is cooled by an aqueous lithium-salt solution that also acts as the breeder material. The use of an aqueous solution imposes special constraints on the selection of structural and breeder material because of corrosion concerns, hydrogen embrittlement, and radiolytic effects. In this paper, the materials engineering and design considerations for the TITAN-II FPC are presented. Material selection criteria, based on electrochemical corrosion mechanisms of aqueous solutions coupled with radiolysis of water by ionizing radiation, resulted in the choice of a low-activation ferritic steel as structural material for TITAN-II. Stress corrosion cracking, hydrogen embrittlement, and changes in the ductile-to-brittle transition temperature of ferritic alloys are discussed. Lithium-nitrate (LiNO3) salt was chosen over lithium hydroxide (LiOH) because it is less corrosive and reduces the net radiolytic decomposition rate of the water. The dissolved salt in the coolant changes the thermophysical properties of the coolant results in trade-offs between the lithium concentration in the coolant, neutronics performance, thermal and structural design. The TITAN-II design requires a neutron multiplier to achieve an adequate tritium breeding ratio. Beryllium is the primary neutron multiplier, assuming a maximum swelling of about 10% based on continuous self-limiting microcracking/sintering cycles.
Maintenance procedures for the TITAN-I and TITAN-II reversed field pinch reactors