A nuclear reactor vessel includes a shell (5) having a wall (9) traversed by at least one passage (11) having a central axis (C) and a valve (21) mounted in the passage (11), the valve (21) having a determined outer cross-section. The passage (11) has an inner end segment (23) that opens into the inner volume (7) and an outer end segment (25) that opens into an outer piping (13), the valve (21) being housed in the inner end segment (23). The valve (21) is capable of being extracted from the passage (11) through the inside of the vessel (1). The outer end segment (25) has at least one portion having an inner cross-section, perpendicular to the central axis (C), that is smaller than the outer cross-section of the valve (21), such that the valve (21) cannot be ejected out of the vessel (1).

Nuclear reactor systems and associated devices and methods are described herein. A representative nuclear reactor system includes a reactor vessel having a barrier separating a core region from a shield region. A plurality of fuel rods containing a liquid nuclear fuel are positioned in the core region. A liquid moderator material is also positioned in the core region at least partially around the fuel rods. A plurality of heat exchangers can be positioned in the shield region, and a plurality of heat pipes can extend through the barrier. The moderator material is positioned to transfer heat received from the liquid nuclear fuel to the heat pipes, and the heat pipes are positioned to transfer heat received from the moderator material to the heat exchangers. The heat exchangers can transport the heat out of the system for use in one or more processes, such as generating electricity.

The present disclosure is directed to systems and methods useful for the construction and operation of a Modular Integrated Gas High-Temperature Reactor (MIGHTR). The MIGHTR includes a reactor core assembly disposed at least partially within a core baffle within a first high-pressure shell portion, a thermal transfer assembly disposed at least partially within a flow separation barrel within a second high-pressure shell portion. The longitudinal axes of the first high-pressure shell portion and the second high-pressure shell portion may be collinear. The reactor core assembly may be accessed horizontally for service, maintenance, and refueling. The core baffle may be flexibly displaceably coupled to the flow separation barrel. Coolant gas flows through the reactor core assembly and into the thermal transfer assembly where the temperature of the coolant gas is reduced. A plurality of coolant gas circulators circulate the cooled coolant gas from the thermal transfer assembly to the reactor core assembly.

The present disclosure is directed to systems and methods useful for the construction and operation of a Modular Integrated Gas High-Temperature Reactor (MIGHTR). The MIGHTR includes a reactor core assembly disposed at least partially within a core baffle within a first high-pressure shell portion, a thermal transfer assembly disposed at least partially within a flow separation barrel within a second high-pressure shell portion. The longitudinal axes of the first high-pressure shell portion and the second high-pressure shell portion may be collinear. The reactor core assembly may be accessed horizontally for service, maintenance, and refueling. The core baffle may be flexibly displaceably coupled to the flow separation barrel. Coolant gas flows through the reactor core assembly and into the thermal transfer assembly where the temperature of the coolant gas is reduced. A plurality of coolant gas circulators circulate the cooled coolant gas from the thermal transfer assembly to the reactor core assembly.

This disclosure describes various configurations and components of a molten fuel fast or thermal nuclear reactor for managing the operating temperature in the reactor core. The disclosure includes various configurations of direct reactor auxiliary cooling system (DRACS) heat exchangers and primary heat exchangers as well as descriptions of improved flow paths for nuclear fuel, primary coolant and DRACS coolant through the reactor components.

This disclosure describes various configurations and components of a molten fuel fast or thermal nuclear reactor for managing the operating temperature in the reactor core. The disclosure includes various configurations of direct reactor auxiliary cooling system (DRACS) heat exchangers and primary heat exchangers as well as descriptions of improved flow paths for nuclear fuel, primary coolant and DRACS coolant through the reactor components.

A component cooling water system for a nuclear power plant. In one embodiment, the system includes an inner containment vessel housing a nuclear reactor and an outer containment enclosure structure. An annular water reservoir is formed between the containment vessel and containment enclosure structure which provides a heat sink for dissipating thermal energy. A shell-less heat exchanger is provided having an exposed tube bundle immersed in water held within the annular water reservoir. Component cooling water from the plant flows through the tube bundle and is cooled by transferring heat to the annular water reservoir. In one non-limiting embodiment, the tube bundle may be U-shaped.

Systems and methods for insulating vessels are disclosed. In one or more embodiments, the disclosure provides a vessel insulation system (e.g., for use with a reactor or pressure vessel), which includes a floating ring sized to circumscribe a top nozzle of a vessel; a plurality of straps connected to the floating ring, the plurality of straps extending downward from the floating ring and being positioned to run along a length of the outer shell of the vessel; and a plurality of segmented rings positioned to circumscribe the outer shell of the vessel and connected to the plurality of straps. The plurality of segmented rings is configured to support an insulation material circumscribing the outer shell of the vessel, which can provide effective securement of the insulation material around the outer shell without welding components on the vessel to secure the insulation material.

Systems and methods for insulating vessels are disclosed. In one or more embodiments, the disclosure provides a vessel insulation system (e.g., for use with a reactor or pressure vessel), which includes a floating ring sized to circumscribe a top nozzle of a vessel; a plurality of straps connected to the floating ring, the plurality of straps extending downward from the floating ring and being positioned to run along a length of the outer shell of the vessel; and a plurality of segmented rings positioned to circumscribe the outer shell of the vessel and connected to the plurality of straps. The plurality of segmented rings is configured to support an insulation material circumscribing the outer shell of the vessel, which can provide effective securement of the insulation material around the outer shell without welding components on the vessel to secure the insulation material.

A passive safety and cooling system for nuclear fission reactors powered by a bundle of radioactive fuel rods enclosed in a pressure vessel provides four redundant levels of dissipating and containing heat. Metal layered with carbon nanotube surrounds the pressure vessel, lines the system's floor, and studs a concrete containment dome. A retractable ceramic tile outer dome contains, absorbs and blocks any remaining heat or nuclear reactions, and optionally, releases them to the atmosphere, for the ultimate dissipation.