The Ultimate Safe (U.S.) Reactor

The Ultimate Safe (U.S.) Reactor is a reactor that eliminates the traditional safety concerns of nuclear fission reactors. The U.S. reactor has an insignificant source term and no reasonable criticality accident. Furthermore, the negligible residual after-heat in the reactor renders its shutdown capability comparable or superior to conventional power sources in that no actions or precautions are required following a shutdown of power. The U.S. Reactor utilizes two principles to achieve ultimate safety. Fission products are continuously removed at the rate they are produced, thus retaining the inherent source term at an insignificant level. The reactor is operated with no excess criticality, hence no criticality accident is reasonably possible. The reactor is controlled safely by its negative temperature coefficient. The reactor maintains criticality by an internal breeding ratio that is trimmed to be exactly one. To facilitate the continuous fission product removal, the U.S. Reactor requires a fluid fuel and on-line, continuous fuel processing. Molten salt fuel was selected for its well-known beneficial properties: low vapor pressure at high temperature; adequate solubility of uranium and thorium as fluorides; good compatibility with structural materials; absence of irradiation damage; high negative temperature coefficient and ample developed technology and experience