NEUTRONICS ASSESSMENT FOR THE ARIES ADVANCED REACTOR STUDIES

The ARIES tokamak designs have incorporated environmental and safety c onstraints in the design from the beginning. Low activation materials such as SiC or SIC composites, vanadium alloy, and modified HT-9 ferri tic steel were utilized as the main structures in ARIES-IV, II, and II I, respectively. All designs employ D-T fuel cycles except ARIES-III w hich is D-He-3 fuelled. An overall tritium breeding ratio of 1.12 seem s adequate for ARIES-II and IV. The Li2O breeder requires a beryllium multiplier to achieve T self-sufficiency in the ARIES-IV design while the lithium has the ability to breed sufficient T in ARIES-II without a multiplier. Radiation damage concerns for the structures are the bur n-up of the SIC and SIC composites and the atomic displacement in the vanadium. The first wall and blanket require frequent replacement (eve ry 3-4 years) during reactor operation. The end-of-life fluences are 1 6.5 MW years m(-2) and 13 MW years m(-2) based on the 200 dpa and 3% b urn-up limits for the V and SiC structures respectively. Because of th e lower neutron production, the ARIES-III first wall and shield are pe rmanent components and require no replacement over the plant lifetime. A variety of shield options was examined and the ability of various m aterials to protect the magnets was assessed. At least 1.2 m and 1.4 m of inboard blanket-shield are required for magnet protection in ARIES -II and ARIES-IV respectively. The lack of T breeding and the lower wa ll loading result in a much thinner shield (0.65 m) for ARIES-III.