Combined moderator-propellant technologies allow a dual-purpose fluid to act as both a nuclear moderator as well as a propellant in a nuclear reactor system, such as a nuclear thermal propulsion (NTP) system. By increasing the mass efficiency of the NTP system and improving the overall performance during operation, the combined moderator-propellant technologies improve valuable payload efficiency in the NTP system. Advantageously, the combined moderator-propellant technologies require little to no dedicated storage space for the majority of NTP system operation. For example, the combined moderator-propellant is ammonia (NH.sub.3), which satisfies moderation requirements as well as propulsion requirements for the NTP system.

A thermal power reactor (100) includes a reactor core (102) that generates thermal energy and a solid state thermal conductor (106) extending into and thermally integrated with the reactor core (102). The solid state thermal conductor (106) transfers thermal energy generated by the reactor core (102) away from the reactor core (102).

An ERVC for floating nuclear power plants includes a containment, a reactor vessel, a liquid gallium collection tank, a heat pipe, a cooling cabin and a gallium storage tank. The containment is arranged in a sea environment, and the containment is provided with a containing cavity; the reactor vessel and the liquid gallium collection tank are arranged up and down and located in the containing cavity. An end of the heat pipe is inserted into the liquid gallium collection tank, and another end thereof is arranged outside the liquid gallium collection tank; the gallium storage tank is located in the containing cavity; the gallium storage tank is connected to the liquid gallium collection tank through a liquid gallium release valve; and the cooling cabin is located under the containment and under a sea level of the sea environment.

A mobile heat pipe cooled fast nuclear reactor may be configured for transportation to remote locations and may be able to provide 0.5 to 2 megawatts of power. The mobile heat pipe cooled fast reactor may contain a plurality of heat pipes that are proximate to a plurality of fuel pins inside the reactor. The plurality of heat pipes may extend out of the reactor. The reactor may be configured to be placed in a standard shipping container, and may further be configured to be contained within a cask and attached to a skid for easier transportation.

A mobile heat pipe cooled fast nuclear reactor may be configured for transportation to remote locations and may be able to provide 0.5 to 2 megawatts of power. The mobile heat pipe cooled fast reactor may contain a plurality of heat pipes that are proximate to a plurality of fuel pins inside the reactor. The plurality of heat pipes may extend out of the reactor. The reactor may be configured to be placed in a standard shipping container, and may further be configured to be contained within a cask and attached to a skid for easier transportation.

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.

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.

An aft plenum assembly for use with a nuclear thermal reactor including a pressure vessel and a nozzle assembly having a top plenum plate disposed within the pressure vessel, the top plenum plate defining a first plurality of fuel flow apertures, a bottom plenum plate disposed within the pressure vessel, the bottom plenum plate being parallel to the top plenum plate thereby defining a plenum space therebetween, the bottom plenum plate defining a second plurality of fuel flow apertures, and a plurality of tubular connections extending between the first plurality of fuel flow apertures of the top plenum plate and the second plurality of fuel flow apertures of the bottom plenum plate, wherein the aft plenum assembly is disposed between the pressure vessel and the nozzle assembly.

An aft plenum assembly for use with a nuclear thermal reactor including a pressure vessel and a nozzle assembly having a top plenum plate disposed within the pressure vessel, the top plenum plate defining a first plurality of fuel flow apertures, a bottom plenum plate disposed within the pressure vessel, the bottom plenum plate being parallel to the top plenum plate thereby defining a plenum space therebetween, the bottom plenum plate defining a second plurality of fuel flow apertures, and a plurality of tubular connections extending between the first plurality of fuel flow apertures of the top plenum plate and the second plurality of fuel flow apertures of the bottom plenum plate, wherein the aft plenum assembly is disposed between the pressure vessel and the nozzle assembly.

Provided is an apparatus for generating electricity, mechanical energy, and/or process and district heat using a gas propellant chamber fueled with fissile material and enclosed in a sealed containment vessel which also contains an operating gas. The system allows for the operating gas to be compressed as it enters the nuclear fuel chamber where it is heated. As the operating gas exits the nuclear fuel chamber, the kinetic energy of the gas is converted to rotational energy by a variety of methods. The rotational energy is further converted to electricity, mechanical energy, and/or process and district heat. The operating gas circulates in the containment vessel and is cooled prior to re-entering the gas propellant chamber. The apparatus thereby provides a simpler and safer design that is both scalable and adaptable. The apparatus is easily and safely transportable and can be designed to be highly nuclear-proliferation-resistant.