The disclosure describes various aspects of a space-based radioisotope production system and methods use. In one aspect, a propellant is accelerated by decay energy to yield thrust. The decay energy is provided by activating a target material. In one aspect, a radioisotope rocket thruster may be recharged or “reactivated” in a space-borne charging station. The activated isotopes may also be used generate electricity. The space-borne charging station may also be used for irradiating other items in space for any number of purposes.

Disclosed embodiments include nuclear fission reactors, nuclear fission fuel pins, methods of operating a nuclear fission reactor, methods of fueling a nuclear fission reactor, and methods of fabricating a nuclear fission fuel pin.

Disclosed embodiments include nuclear fission reactors, nuclear fission fuel pins, methods of operating a nuclear fission reactor, methods of fueling a nuclear fission reactor, and methods of fabricating a nuclear fission fuel pin.

A molten chloride fast reactor (MCFR) includes a plurality of reflectors defining a central core having a core geometric center. A flow channel fluidically connected to the central core. The flow channel includes an outlet flow channel downstream of the central core and an inlet flow channel upstream from the central core. A primary heat exchanger (PHX) disposed outside the central core and between the outlet flow channel and the inlet flow channel. The MCFR also includes a decay heat heat exchanger (DHHX). At least a portion of the DHHX is disposed above the core geometric center, and a fuel salt is configured to circulate at least partially through the outlet flow channel, the DHHX, the PHX, the inlet flow channel, and the central core.

A molten chloride fast reactor (MCFR) includes a plurality of reflectors defining a central core having a core geometric center. A flow channel fluidically connected to the central core. The flow channel includes an outlet flow channel downstream of the central core and an inlet flow channel upstream from the central core. A primary heat exchanger (PHX) disposed outside the central core and between the outlet flow channel and the inlet flow channel. The MCFR also includes a decay heat heat exchanger (DHHX). At least a portion of the DHHX is disposed above the core geometric center, and a fuel salt is configured to circulate at least partially through the outlet flow channel, the DHHX, the PHX, the inlet flow channel, and the central core.

A heat transfer (exchange) composition comprising a halide salt matrix having dispersed therein nanoparticles comprising elemental carbon in the absence of water and surfactants, wherein said halide is fluoride or chloride, wherein the halide salt may be an alkali halide salt (e.g., lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, sodium chloride, potassium chloride, rubidium chloride, and eutectic mixtures thereof) or an alkaline earth halide salt (e.g., fluoride or chloride salt of beryllium, magnesium, calcium, strontium, or barium), and wherein the nanoparticles comprising elemental carbon may be solid or hollow, and wherein the composition may further include nanoparticles comprising a fissile material (e.g., U, Th, or Pu) dispersed within the composition. Molten salt reactors (MSRs) containing these heat transfer compositions in coolant loops in thermal exchange with a reactor core, as well operation of such MSRs, are also described.

A heat transfer (exchange) composition comprising a halide salt matrix having dispersed therein nanoparticles comprising elemental carbon in the absence of water and surfactants, wherein said halide is fluoride or chloride, wherein the halide salt may be an alkali halide salt (e.g., lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, sodium chloride, potassium chloride, rubidium chloride, and eutectic mixtures thereof) or an alkaline earth halide salt (e.g., fluoride or chloride salt of beryllium, magnesium, calcium, strontium, or barium), and wherein the nanoparticles comprising elemental carbon may be solid or hollow, and wherein the composition may further include nanoparticles comprising a fissile material (e.g., U, Th, or Pu) dispersed within the composition. Molten salt reactors (MSRs) containing these heat transfer compositions in coolant loops in thermal exchange with a reactor core, as well operation of such MSRs, are also described.

A heat transfer (exchange) composition comprising a halide salt matrix having dispersed therein nanoparticles comprising elemental carbon in the absence of water and surfactants, wherein said halide is fluoride or chloride, wherein the halide salt may be an alkali halide salt (e.g., lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, sodium chloride, potassium chloride, rubidium chloride, and eutectic mixtures thereof) or an alkaline earth halide salt (e.g., fluoride or chloride salt of beryllium, magnesium, calcium, strontium, or barium), and wherein the nanoparticles comprising elemental carbon may be solid or hollow, and wherein the composition may further include nanoparticles comprising a fissile material (e.g., U, Th, or Pu) dispersed within the composition. Molten salt reactors (MSRs) containing these heat transfer compositions in coolant loops in thermal exchange with a reactor core, as well operation of such MSRs, are also described.

The present invention describes a nuclear reactor with a loop for liquid nuclear fuel, which, contrary to similar systems like the Molten-Salt Reactor of the Generation-IV canon, does not use the fuel loop for the heat transport at the same time. Instead, cooling is provided by an additional coolant loop, which is intensively coupled to the nuclear fuel duct for heat transport. That way, the advantages of liquid fuel can be utilized while optimizing the coolant loop performance, so the complexity of safety systems can be reduced significantly. This reactor design further includes an optimized neutron economy and is able to deactivate long-lived fission products generated by its own, so only short-lived radiotoxic waste has to be stored. With the neutron surplus it is also possible to deactivate long-lived radiotoxic waste from used fuel of today's light water reactors or to produce medical radioisotopes.

The present invention describes a nuclear reactor with a loop for liquid nuclear fuel, which, contrary to similar systems like the Molten-Salt Reactor of the Generation-IV canon, does not use the fuel loop for the heat transport at the same time. Instead, cooling is provided by an additional coolant loop, which is intensively coupled to the nuclear fuel duct for heat transport. That way, the advantages of liquid fuel can be utilized while optimizing the coolant loop performance, so the complexity of safety systems can be reduced significantly. This reactor design further includes an optimized neutron economy and is able to deactivate long-lived fission products generated by its own, so only short-lived radiotoxic waste has to be stored. With the neutron surplus it is also possible to deactivate long-lived radiotoxic waste from used fuel of today's light water reactors or to produce medical radioisotopes.