Abstract: A passive cooling system using only reactive processes without moving parts to power its startup and operation is designed to maximize the reliability of decay heat removal for the current generation of nuclear power plants and for advanced passive reactors. In order to reduce the number of failure modes processes independent from any external power source—such as the electrical power grid or Diesel generators—are used exclusively for all safety functions. The system uses the very energy that could cause an accident to circulate cooling water through the steam generator to remove the decay heat, simplifying the design and reducing capital costs significantly. Decay heat generated by the nuclear fuel after reactor shutdown induces coolant circulation from the steam generator to the ultimate heat sink keeping the nuclear fuel at safe temperatures and preventing any release of radioactive fission products to the environment.

Abstract: A heat dissipation system for removing the decay heat from a nuclear reactor after a failure in the main coolant system. The heat dissipation system provides a fluid circulation conduit in which a condensible fluid is circulated. Heat removed from the circulating fluid is utilized to vaporize condensate and thereby power a jet circulator that provides the motive force for continued fluid circulation. A heat exchanger in the fluid circulation conduit removes and rejects heat from the circulating fluid to continuously remove and reject heat from the system.