A power generation system includes an inert gas power source, a thermal/electrical power converter and a power plant. The thermal/electrical power converter includes a compressor with an output coupled to an input of the inert gas power source. The power plant has an input coupled in series with an output of the thermal/electrical power converter. The thermal/electrical power converter and the power plant are configured to serially convert thermal power produced at an output of the inert gas power source into electricity. The thermal/electrical power converter includes an inert gas reservoir tank coupled to an input of the compressor via a reservoir tank control valve and to the output of the compressor via another reservoir tank control valve. The reservoir tank control valve and the another reservoir tank control valve are configured to regulate a temperature of the output of the thermal/electrical power converter.

Systems, methods, and devices of the various embodiments enable a Nuclear Thermionic Avalanche Cell (NTAC) to capture gamma ray photons emitted during a fission process, such as a fission process of Uranium-235 (U-235), and to breed and use a new gamma ray source to increase an overall emission flux of gamma ray photons. Various embodiments combine a fission process with the production of Co-60, thereby boosting the output flux of gamma ray photons for use by a NTAC in generating power. Various embodiments combine a fission process with the production of Co-60, a NTAC generating avalanche cell power, and a thermoelectric generator generating thermoelectric power.

Systems, methods, and devices of the various embodiments enable a Nuclear Thermionic Avalanche Cell (NTAC) to capture gamma ray photons emitted during a fission process, such as a fission process of Uranium-235 (U-235), and to breed and use a new gamma ray source to increase an overall emission flux of gamma ray photons. Various embodiments combine a fission process with the production of Co-60, thereby boosting the output flux of gamma ray photons for use by a NTAC in generating power. Various embodiments combine a fission process with the production of Co-60, a NTAC generating avalanche cell power, and a thermoelectric generator generating thermoelectric power.

The invention provides a core of a fast reactor including a sodium plenum installed above a core fuel, which is capable of reliably reducing a void reactivity, and an operation method thereof. The core of a fast reactor including the sodium plenum installed above the core fuel is characterized in that a tip of a primary control rod is inserted into a core fuel region, and a tip of a backup control rod is arranged above an upper end of the core fuel region for operation.

The invention provides a core of a fast reactor including a sodium plenum installed above a core fuel, which is capable of reliably reducing a void reactivity, and an operation method thereof. The core of a fast reactor including the sodium plenum installed above the core fuel is characterized in that a tip of a primary control rod is inserted into a core fuel region, and a tip of a backup control rod is arranged above an upper end of the core fuel region for operation.

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 fast neutron nuclear reactor contains a nuclear reactor core having an array of device locations. Some device locations in the nuclear reactor core contain fissile and fertile nuclear fuel assembly devices. One or more other device locations in the nuclear reactor core contain Doppler reactivity augmentation devices that amplify the negativity of the Doppler reactivity coefficient within the nuclear reactor core. In some implementations, a Doppler reactivity augmentation device can also reduce the coolant temperature coefficient within the nuclear reactor core. Accordingly, a Doppler reactivity augmentation device contributes to a more stable nuclear reactor core.

Sodium-tin and sodium-tin-lead compositions have been identified and created that exhibit better reactivity characteristics (i.e., are less reactive) than sodium metal under the same conditions, making these compositions safer alternatives to sodium metal for use as a coolant. These compositions include compositions having at least 90% sodium (Na), from 0-10% lead (Pb) and the balance being tin (Sn).

Sodium-tin and sodium-tin-lead compositions have been identified and created that exhibit better reactivity characteristics (i.e., are less reactive) than sodium metal under the same conditions, making these compositions safer alternatives to sodium metal for use as a coolant. These compositions include compositions having at least 90% sodium (Na), from 0-10% lead (Pb) and the balance being tin (Sn).

Cover gas control systems include a reservoir and injection path for direct injection into fuel transfer machinery. If seals in the fuel handling machinery leak, cover gas is provided from the reservoir to flow to the leak without contamination from a reactor to which the fuel transfer machinery is joined. This providing cover gas may be passive or automatic in response to a detected low pressure level, detected ambient air ingress, low volume level of cover gas, or manually actuated through an operator. The cover gas may be injected from below the leak but above the reactor. A limitation in the injection path keeps cover gas injection at rates sufficient to allow operator reaction and sealing before the reservoir is depleted. A pressure pulse transmitter, blowout preventer, and transfer port plug are useable in the systems, which can be implemented in fuel handling machinery for reactors using a cover gas.