Neutronics analysis for the stellarator power plant study SPPS

The neutronics activities for SPPS included the determination of the blanket dimensions that provide tritium self-sufficiency, radiation damage to the structural materials, lifetime of the in-vessel components, radiation level at the superconducting magnets, and shielding requirements for magnet protection. The neutron wall loading varies in both poloidal and toroidal directions. For an average wall loading of 1.3 MW/m/sup 2/, the distribution peaks at 2 MW/m/sup 2/. The 35 cm thick blanket will breed sufficient tritium to ensure the self-sustaining operation of the DT fueled stellarator. The blanket utilizes the liquid lithium as a coolant and breeder and the low activation vanadium alloy VSCr5Ti as a structural material. The first wall and blanket will be replaced every 11 years due to radiation to the vanadium structure. The shield follows the blanket and is primarily used to protect the magnets against radiation. Since the dimensions of the shield directly affect the size and cost of the machine, an extensive analysis was performed for the shield including evaluation of candidate materials, variation of composition, and computation of radiation effects on magnets. The shield is 80 cm thick and is made of berated steel filler supported by V structure. A successful attempt was made to lower the cost of the shield while keeping the attractive safety features of the design.