An Assessment Of Critical Thermal-Hydraulic Problems in A Deuterium-Tritium Solid Breeder Blanket

Steady-state thermal-hydraulic analyses were carried out for the DEMO/STARFIRE fusion reactor based on solid breeder blankets and pressurized water as the coolant. The results of the parametric studies show that a coolant in-tube design, i.e., coolant tubes embedded in solid breeder blanket, with a contact resistance between the coolant tube and the solid breeder tailored to maintain the operating temperature window (i.e., the maximum and the minimum temperature imposed on the solid breeder) is viable. However, design of such a solid breeder blanket will present serious challenges because of uncertainty in the thermophysical properties of breeder materials, the narrow operating temperature window, the close manufacturing tolerances necessary to control the gap conductance, the sensitivity of tritium inventory and tritium extraction to breeder temperature distribution, and the deleterious effect of neutron irradiation on breeder material properties. The study shows that even modest uncertainties in the thermal conductivity of solid breeders, interfacial gap conductances, and operating power levels can have significant impact on blanket design. Therefore, the designer should include the expected variations in these parameters. Experimental programs are needed to quantify the above factors and to develop methods (e.g., insulated coatings) for gap conductance control and in situ recovery of tritium via helium purge gas channels.