Neutronic studies for the ARIES-I reactor

A high-performance, helium-cooled, solid-breeder fusion blanket was designed for the ARIES-I (Advanced Reactor Innovation and Evaluation Study-I) reactor. The Li₄SiO₄ breeder material is placed behind a beryllium zone to maximize the beryllium neutron multiplication. A modest beryllium inventory of about 40 t is needed to achieve a blanket energy multiplication of 1.35 or more, while breeding adequate tritium in the blanket. The decay heat values and radiological hazard potentials of ARIES-I blanket and shield (SiC+B₄C) materials are found to be at least two to three orders of magnitude lower than those from metallic alloys such as ferritic steel and vanadium alloy. Inherent safety will be achieved for the ARIES-I blanket because the minimum radioactive inventory precludes meltdown of the first wall and structural SiC material. However, the safety design of the divertor which uses tungsten alloy particle-collector plates and vanadium alloy structure will need to be carefully done because of higher levels of afterheat. All ARIES-I components will qualify for disposal as 10 CFR 61 Class-C waste if averaging over the first wall and blanket component is allowed, and if some exotic impurity elements (Ag, Nb, Mo) are controlled below 1 p.p.m