A multipurpose passive residual heat removal system for a small fluoride-salt-cooled high-temperature reactor is provided, including: a circulation loop composed of a reactor body system, a multipurpose passive residual heat removal system, pipes and other connecting equipment between each system; wherein the reactor body system serves as the heat source of the system, using helical cruciform fuel element and FLiBe molten salt coolant, wherein a thermal power is 125 MW, and a temperature of the core outlet reaches 700° C., which has the advantages of high-temperature and low-pressure operation, inherent safety and compact structure. The multipurpose passive residual heat removal system not only serves as a special safety facility to ensure the passive safety of the reactor, but also efficiently recovers and utilizes the residual heat through the thermoelectric power generation device for power generation.

The present invention relates to a device adapted for producing energy by nuclear fission, the device comprising a core container of a core container material, which core container encloses an inner tubing of an inner tubing material, the inner tubing and/or the core container having an inlet and an outlet, the device further comprising a molten halide salt located in the core container or in the inner tubing, wherein the inner tubing comprises one or more sections consisting of single crystal corundum. The invention further relates to methods of controlling nuclear fission processes using the device and to the use of a corundum tube as a structural material in a nuclear fission device. The invention provides improved economy in molten salt nuclear fission processes.

Configurations of molten fuel salt reactors are described that allow for active cooling of the containment vessel of the reactor by the primary coolant. Furthermore, naturally circulating reactor configurations are described in which the reactor cores are substantially frustum-shaped so that the thermal center of the reactor core is below the outlet of the primary heat exchangers. Heat exchanger configurations are described in which welded components are distanced from the reactor core to reduce the damage caused by neutron flux from the reactor. Radial loop reactor configurations are also described.

Some embodiments include a method comprising: flowing a molten salt out of a molten salt reactor at a first temperature, heating the molten salt reactor to a second temperature above the melding point of the second salt mixture causing the second salt mixture to melt; flowing the second salt mixture out of the molten salt reactor; flowing a third salt mixture into the molten salt reactor; and cooling the molten salt reactor from the second temperature to a third temperature causing the third salt mixture to solidify on the interior surface of the housing. In some embodiments, the molten salt may include a first salt mixture comprising at least uranium. In some embodiments, the first temperature is a temperature above the melting point of the first salt mixture.

System of endothermic emergency cooling for nuclear reactors using passive convection cooling and an endothermic reactant system.

System of endothermic emergency cooling for nuclear reactors using passive convection cooling and an endothermic reactant system.

A passive reactor cavity cooling system according to the present invention includes: a reactor cavity formed between a reactor vessel and a containment structure enclosing the reactor vessel; a first cooling system to control external air to sequentially pass through an air falling pipe and an air rising pipe provided in the reactor cavity, so that residual heat of a core transferred to the reactor cavity is discharged to the atmosphere; a second cooling system having a water cooling pipe disposed in an inner space of the containment structure or in a wall of the containment structure to discharge the residual heat of the core transferred to the reactor cavity to outside; and a functional conductor having an insulating property in a normal operation temperature range of the reactor and a heat transfer property in an accident occurrence temperature range of the reactor which is a higher temperature environment than the normal operation temperature range, wherein the air falling pipe and the water cooling pipe are disposed behind the air rising pipe with respect to a direction viewed from the reactor vessel, and the functional conductor is disposed between the air falling pipe and the air rising pipe.

A passive reactor cavity cooling system according to the present invention includes: a reactor cavity formed between a reactor vessel and a containment structure enclosing the reactor vessel; a first cooling system to control external air to sequentially pass through an air falling pipe and an air rising pipe provided in the reactor cavity, so that residual heat of a core transferred to the reactor cavity is discharged to the atmosphere; a second cooling system having a water cooling pipe disposed in an inner space of the containment structure or in a wall of the containment structure to discharge the residual heat of the core transferred to the reactor cavity to outside; and a functional conductor having an insulating property in a normal operation temperature range of the reactor and a heat transfer property in an accident occurrence temperature range of the reactor which is a higher temperature environment than the normal operation temperature range, wherein the air falling pipe and the water cooling pipe are disposed behind the air rising pipe with respect to a direction viewed from the reactor vessel, and the functional conductor is disposed between the air falling pipe and the air rising pipe.

An anti-proliferation technique is disclosed to reduce the likelihood of nuclear proliferation due to the use fissionable fuel salts. The technique includes doping the fuel salt with one or more elements (referred to herein as activation dopants) that, upon exposure to neutrons such as would occur in the fuel salt when a reactor is in operation, undergo a nuclear reaction to, directly or indirectly, form highly active “protecting isotopes” (of the same element as the activation dopant or a different element). A sufficient mass of activation dopants is used so that the Figure of Merit (FOM) of the fuel salt is decreased to below 1.0 within some target number of days of fission. This allows the FOM of the fuel salt to be controlled so that the fuel becomes too dangerous to handle before to the creation of a significant amount of weaponizable isotopes.

In a panel that uses the gamma radiation emitted by fission to produce electrical power, a source of an electrical current is connected to a layer of the panel made of a metal with a relatively high atomic number (Z) that forms an electron emitter. The emitter layer is surrounded by an insulation layer which in turn is surrounded by a relatively low Z value layer for collecting electrons from the emitter. Another layer of insulation and an outer sheath surround the collector. The improved panel may be used for reactor power level and power distribution measurements, and for initiating, maintaining or returning molten salt or metal coolants in the liquid state.