91results about "Fast fission reactors" patented technology

The present invention relates to a reactor construction comprising an upper compartment above a reactor compartment, said reactor compartment being separated from the upper compartment by a radiation shield, wherein a molten salt reactor (MSR) is situated in the reactor compartment, the MSR comprising a reactor vessel with a reactor vessel lid assembly comprising a reactor vessel lid shield and a reactor vessel lid wherein a lifting element is situated in the reactor construction, the lifting element comprising: at least one bar being substantially vertical and axially adjustable along its longitudinal axis by a drive mechanism situated in the upper compartment, and wherein at least one through-hole for the at least one bar is provided in the radiation shield and wherein the reactor vessel lid shield has at least one receiving structure configured to engage with and lock to the at least one bar. The invention also relates to a method of performing a maintenance operation in the reactor compartment and a power barge comprising at least one reactor construction.

A nuclear reactor is designed to couple the load path of the control elements with the reactor core, thus reducing the opportunity for differential movement between the control elements and the reactor core. A cartridge core barrel can be fabricated in a manufacturing facility to include the reactor core, control element supports, and control element drive system. The cartridge core barrel can be mounted to a reactor vessel head. Thus, any movement, such as through seismic forces, transmits an equal direction and magnitude to the control elements and the reactor core. This arrangement reduces the opportunity for differential movement between the control elements and the reactor core.

A liquid metal cooled nuclear reactor includes a passive decay heat removal system having thermal insulation attached to a wall of a cold source reservoir that holds a phase change material, where the insulation is arranged to automatically fall by gravity from the wall in response to the wall reaching a predetermined temperature. The nuclear reactor may be a fast neutron reactor that incorporates an integral system having a final cold source with a reservoir incorporating an integral exchanger divided into a plurality of parallel tubes between which a phase change material is inserted, the reservoir being surrounded by a thermal insulating layer that can be detached in a passive manner in the event of reaching a predetermined threshold temperature.

Fuel bundle has plurality of twisted ribbon fuel rodlets in hexagonal packing or circle packing arrangement in a core region encased in a multilayer casing. Arrangement of twisted ribbon fuel rodlets is facilitated by rodlet seating fixture with seating surface having a plurality of protrusions that form a receiving space for ends of the twisted ribbon fuel rodlets. Manufacture of the fuel bundle incorporates fiber manufacturing technologies and, optionally, infiltration of void spaces in core region by infiltrant. Twisted ribbon fuel rodlet manufacturing system has sub-systems that impart twist periodicity to extruded ribbons, inspect twisted extruded ribbons, and cut twisted extruded ribbons to length. Inspection sorts twisted ribbon fuel rodlets as well as provides feedback to adjust operation of sub-systems. The fuel bundle (and optional fuel bundle support) can be incorporated into a fuel assembly of a nuclear propulsion fission reactor structure of, for example, a nuclear thermal propulsion engine.

Regarding molten salts used in contact with graphite in nuclear reactors, there is a need for them to be easily maintained under strong reducing conditions without causing graphite degradation. [Solution] Use of a molten salt containing aluminum trifluoride and sodium fluoride as a primary coolant for a nuclear fission reactor, wherein the molten salt comes into contact with graphite and aluminum metals during the operation of the nuclear fission reactor.

Molten salt nuclear reactor, of the fast neutron type with a safety vessel around the reactor vessel and a drain tank below the vessels. The invention relates to a nuclear reactor (1) comprising: - at least one nuclear reactor vessel (2) (1) filled with a molten salt fuel bath and provided with at least one outlet in its bottom; - another vessel (8), called the safety vessel, arranged around the reactor vessel by defining an inter-vessel space (E) with the reactor vessel; - a tank (10), called the drain tank, arranged below the vessels, and connected to the inter-vessel space by at least one pipe (11) and to the outlet of the reactor vessel by at least one pipe (12); - a selective closure device (13) for the outlet of the reactor vessel, in the closed position during normal reactor operation and in the open position to carry out the emptying of the reactor vessel.Figure for the abridged version: fig.3.

Heat pipe fuel element includes an evaporation section, a condensing section, a capillary section connecting the evaporation section to the condensing section, and a primary coolant. In a cross-section in a plane perpendicular to a longitudinal axis of the evaporation section, the heat pipe fuel element includes a cladding layer enclosing an interior area including a fuel body formed of a fissionable fuel composition and that has an outer surface oriented toward the cladding layer and an inner surface defining a periphery of a vaporization space of the evaporation section. The fuel body has a structure with a shape corresponding to a mathematically-based periodic solid, such as a triply periodic minimal surface (TPMS), and the evaporation sections of a plurality of heat pipe fuel elements are arranged in a phyllotaxis pattern (as seen in a cross-section in a plane perpendicular to a longitudinal axis of the active core region).

The invention relates to a nuclear power plant comprising: - a reactor building (10); - at least two reactor pits implanted inside the reactor building, - at least two reactor vessels (2) of molten salt fast neutron nuclear reactors (1), the reactor vessels exhibiting axial symmetry about a central axis, internally delimiting a primary circuit for a fuel in liquid form in which at least one salt is melted, the interior of the vessel being devoid of moderator material; each of the reactor vessels being housed in one of the two reactor pits; and - means for transferring the molten salt fuel from inside one of the two reactor vessels into the other of the two reactor vessels.

A molten salt reactor system includes a fuel salt system and a coolant salt system. The fuel salt system is configured to circulate a molten fuel salt through a molten salt loop. The coolant salt system is configured to circulate a coolant salt through a coolant loop. The molten salt reactor system further includes a heat exchanger arranged along the molten salt loop and the coolant loop. The heat exchanger is configured to transfer heat from the molten fuel salt of the molten salt loop to the coolant salt of the coolant loop. The heat exchanger is configured to permit gravitational draining of at least one of the molten fuel salt or the coolant salt upon a shutdown event.

In some embodiments, a nuclear reactor may include a vessel having a wall defining an interior cavity. The nuclear reactor may include a core disposed within the interior cavity. The core may include heat-generating fuel and a primary medium for transferring heat from said fuel to an outer boundary of said core. Said primary medium may be one or more solid materials. In some embodiments, a system may include a nuclear reactor having a core comprising an active region containing a. fissionable fuel operating at criticality within a predetermined temperature range. At least fifty (50) percent of heat transferred within said active region may be transferred by conduction only.

Fission of uranium-235 produces a wide range of fission products. Of particular importance is the production of molybdenum-99 due to its uses in the medical field. Fission products can be extracted from a molten salt reactor through electrochemical deposition by utilizing an electrode submerged in the flow of irradiated molten salt. However, this is likely to disrupt the redox of the irradiated molten fuel leading to harmful corrosion of the reactor. The present invention utilizes three electrode sets to capture fission products from irradiated molten salt of a molten salt reactor, monitor the redox behavior of the irradiated molten salt, and maintaining the balance of uranium ions to avoid harmful corrosion to the reactor's core.

A method and system for an in-vessel natural circulation alkali metal reactor system, a cleanup system, and associated methods are disclosed. The reactor vessel system includes an inner vessel defining an interior volume sized to at least partially surround a nuclear reactor. The reactor includes a plurality of nuclear fuel elements at least partially surrounded by cladding, and the reactor is cooled by a liquid metal coolant in a primary coolant loop. A pool of immersion fluid occupies a volume inside the inner vessel. The reactor vessel system includes an outer vessel sized to completely or substantially surround the inner vessel. The nuclear reactor power system includes a reactor core including an active fuel region and a rotatable drum including at least one of a neutron absorbing material, a neutron leakage enhancing material, or a neutron reflecting material, the rotatable drum being positioned outside the active fuel region of the reactor core.

Fuel, intended to be irradiated in a fast neutron nuclear reactor, comprising grains of at least one metal selected from U, Pu or Th, the grains being compressed in a volume, the fuel being porous, the fuel being characterized in that it comprises open intergranular pores, forming an interconnected porosity, the volume fraction of porosity preferably being between 3% and 30%, more than 50% or 80% of the porosity being an open intergranular porosity,

Embodiments of nuclear fuel elements for various types of nuclear reactors are disclosed. One embodiment of a nuclear fuel element includes a plurality of solid nuclear fuel particles, such as tri-structure-isotropic (TRISO) fuel particles, mixed in a non-solid matrix that is substantially stagnated relative to the plurality of solid nuclear fuel particles. The non-solid matrix may include a liquid metal, a liquid metal alloy, and a liquid salt. Various embodiments of the non-solid matrix include tin, lead, sodium, aluminum, bismuth, and alloys thereof. Embodiments of a method of manufacturing a nuclear fuel and a nuclear fuel core including the nuclear fuel element are also disclosed.

A fuel assembly for use in a nuclear reactor comprising a fuel bundle, a plenum header connection positioned on the fuel bundle, a mast extending from the fuel bundle, and a common fission gas plenum extending from the mast is disclosed. The reactor includes a vessel and coolant situated within the vessel. The fuel bundle comprises a plurality of fuel elements including nuclear fuel material positioned therein. The plenum header connection comprises a plurality of passageways defined therein that are in fluid communication with the nuclear fuel material. The elongate mast comprises an internal passage connecting the common fission gas plenum to the plurality of passageways of the plenum header connection such that the common fission gas plenum is configured to receive an amount of fission gas generated by the nuclear fuel material during operation. The common fission gas plenum is positioned in an otherwise unused portion of the vessel.

A protection system (1) for the shutdown of a nuclear reactor comprises a first volume (V1) and a second volume (V2), communicating with each other at respective lower ends and containing a process fluid (F) and a pressurised gas; and a gas regulation system (13) to regulate the gas pressure in the volumes (V1, V2); the first volume (V1) comprises a neutron absorber (16) immersed in the process fluid (F) in a lower portion (15) of the first volume (V1) and having a lower density than the process fluid (F), and a constraint element (20) placed above the absorber (16) and pushed downwards by the lowering of the level of the process fluid (F) due to the pressure of the gas contained in the first volume (V1) to keep the absorber (16) in the lower portion (15) against the buoyancy thrust exerted by the process fluid (F); the constraint element (20) is vertically sliding in the first volume (V1) as the gas pressure in the first volume (V1) varies so as to vary the vertical position of the absorber (16) to bring the absorber (16) to face in use to an active portion (A) of the core (C) of the reactor (R).

The present invention relates to a reactor construction (1) comprising an upper compartment (2) above a drain tank compartment (3), said upper compartment (2) comprising: a molten salt reactor (MSR) (4), comprising a reactor vessel (5) comprising a molten fuel salt (6); a molten salt drain system connected to the reactor vessel (5); said drain tank compartment (3) comprising: one or more drain tanks (10) in communication with the molten salt drain system; a buffer water tank (15) comprising an inner wall (16) and an outer wall (17) and buffer water (21) in the gap between the inner wall (16) and the outer wall (17) of the buffer water tank (15), said buffer water tank (15) surrounding the one or more drain tanks (10), wherein a first piping structure (22) is defining a circuit for at least part of the buffer water (21) and comprising a heat exchanger (23) in thermal contact with a reservoir water tank (30), said reservoir water tank (30) being at a level above the buffer water tank (15), said reservoir water being in thermal contact with an environment and / or a second piping structure (24) is defining a circuit for at least part of the buffer water (21) and comprising a heat exchanger (25) in thermal contact with an environment, said heat exchanger (25) being at a level above the buffer water tank (15) and / or a seawater heat exchanger (26) in thermal contact with the buffer water (21) and seawater, said seawater heat exchanger (26) being located below seawater level outside the outer wall (17) of the buffer water tank (15).

A sodium leak detection system for a nuclear reactor vessel includes a recirculation loop having an inlet and an outlet in communication with the annular space between the nuclear reactor vessel and the guard vessel. The recirculation loop and the annulus are filled with an inert gas, such as argon. The inert gas is doped with a known trace quantity of oxygen, typically in the single-digit ppm range up to about 1%. A recirculator forces the inert gas and oxygen to mix and flow throughout the annulus. The recirculation loop further includes a trace oxygen sensor that determines the concentration of oxygen in the inert gas. Because sodium reacts with oxygen, the trace oxygen sensor is monitored for a reduction in the oxygen level, which indicates a sodium leak into the annulus.

A molten salt reactor system includes a fuel salt system configured to circulate a molten salt through a reactor vessel. The molten salt reactor system further includes an inert gas system fluidically coupled with the fuel salt system and configured to maintain a pressurized volume in a head space of a drain tank by circulating an inert gas along a first inert gas flow path. The molten salt reactor system further includes an equalization system configured to equalize pressure between head spaces of the reactor vessel and the drain tank in response to a reactor shutdown event. The inert gas system is configured to cease maintenance of the pressurized volume in response to the reactor shutdown event.

The invention relates to a fast-neutron nuclear reactor (1), which comprises: - a reactor vessel (10) filled with a heat-transfer fluid, - a reactor core (11) consisting of fuel assemblies (13), - a reactivity control system (2), at the periphery of the core, in a cold plenum zone or in the hot plenum, between the reactor vessel and the separation step between the hot and cold plenums, such that the cold heat-transfer fluid passes through the assemblies or monolithic reactivity control rods.

A fast neutron nuclear reactor, in particular liquid-metal cooled, with a reactivity control system arranged on the periphery of the nuclear core. The invention relates to a fast neutron nuclear reactor (1) comprising: - a reactor vessel (10) filled with a coolant, - a reactor core (11) consisting of fuel assemblies (13), - a reactivity control system (2), on the periphery of the core, in a cold manifold zone, between the reactor vessel and the separation step between the hot and cold manifolds, such that the reactivity control assemblies or monoblock rods are traversed by the cold coolant. Figure for the abstract: Fig. 2

A molten salt reactor system includes a fluid level control system configured to circulate a molten salt through a molten salt loop including an experimental tank, a sump tank, and a drain tank. The fluid level control system further includes a plurality of level sensors, pressure transducers, and electronic pressure regulators fluidically coupled with the fuel salt system. The fluid level control system is configured to receive cover gas pressures in the headspaces of the tanks and calculate target fluid height setpoints for each of the tanks. The fluid level control system further invokes the electronic pressure regulator to iteratively adjust the cover gas pressures of the tanks to achieve and maintain a target fluid level in the experimental tank.

To provide a fusion-driven subcritical reactor that is more efficient and safer. [Solution] A fusion-driven subcritical reactor is a nuclear reactor that starts and operates by amplifying neutrons obtained from nuclear fusion and supplying the amplified neutrons to a reactor that holds subcritical nuclear fuel by external neutrons. It consists of a main neutron source that generates DD neutrons through a nuclear fusion reaction, a cascade member that surrounds the main neutron source, separates fusion / fission neutrons, multiplies the fast fission neutrons generated by nuclear fission, and slows down the fast fission neutrons, and a cascade member that surrounds the cascade member and is mainly made of thorium oxide ( 232 It is equipped with a subcritical main fission blanket made of uranium dioxide (ThO2), and a neutron flattening blanket that has a neutron source located around the outer periphery of the main fission blanket to improve the containment of fission neutrons.

One variation of a system includes: a nuclear reactor; a shield arranged about the nuclear reactor; a metallic coolant; and a set of melt seals. The nuclear reactor includes a pressure vessel and nuclear fuel arranged within a lower region of the pressure vessel. The metallic coolant includes a mixture of metals and is configured to: occupy a liquid state within an operating temperature range; occupy an interstitial volume between the nuclear reactor and the shield; and occupy the lower region of the pressure vessel encompassing the nuclear fuel. The set of melt seals are arranged on the pressure vessel and configured to open to enable transfer of a volume of the metallic coolant from the interstitial volume into the lower region of the pressure vessel in response to temperatures within the pressure vessel exceeding the operating temperature range.

To provide a system that enables a heat exchanger contained in a nuclear reactor vessel to be compact.SOLUTION: The system comprises: a nuclear reactor on a nuclear reactor site; a nuclear reactor site boundary defined by one or more barriers inhibiting access to the nuclear reactor site; a thermal energy storage system located outside the nuclear reactor site boundary; and a power generator situated outside the nuclear reactor site boundary. The nuclear reactor comprises a nuclear reactor vessel, a primary coolant loop, and a primary heat exchanger. The primary heat exchanger is a sodium to salt heat exchanger disposed in the nuclear reactor vessel.SELECTED DRAWING: Figure 10

To provide a thermal energy storage system connected to both a nuclear reactor and a generator.SOLUTION: The integrated energy system includes a nuclear heat plant located at a nuclear reactor site. Nuclear heat plants produce thermal energy that is transported to a thermal energy storage system located outside of the reactor site. The thermal storage system is thermally coupled to a power generation system that is also remote to the reactor site. This arrangement isolates and decouples the nuclear heat plant from the power generation system. Nuclear heat plants may provide thermal energy at 800 °C. or higher to be stored in a thermal energy storage system until needed, such as for industrial heat, power generation systems, or other applications. The thermal storage system is tolerant as to source, and one or more additional thermal energy generators, such as additional nuclear reactors, solar thermal plants, or other thermal energy generators, may be coupled to the common thermal storage system and power generation system.SELECTED DRAWING: Figure 12B

A nuclear reactor is disclosed. The nuclear reactor comprises a vessel closed at the top by a roof and housing a core, comprising a bundle of fuel elements. The core being supported by a lower support supporting a lower portion of the core below an active zone of the fuel elements; and an upper support supporting an upper portion of the core above the active zone of the fuel elements; the upper support is joined to the roof by a support structure extending from the roof and has an end element centrally open and internally provided with a plurality of jaws for vertical support and elastic radial constraint of the fuel elements.

Heat exchanger with at least two fluid circulation circuits, with a jacket of two concentric cylinders between which are arranged plates of general involute shape; Use in a nuclear reactor with molten liquid salt(s).The invention relates to a two-circuit fluid heat exchanger (3) comprising: - a casing (30) formed by two concentric hollow cylinders (31, 32) with a central axis (X), defining an annular space between them; - plates (300), each having a straight cross-section perpendicular to the central axis X in the form of a portion of an involute of a circle or a curve with a radius of curvature increasing from the inner cylinder to the outer cylinder and close to an involute of a circle, the plates each connecting the two cylinders of the casing and being parallel to each other in the annular space, delimiting between them, on either side of the same plate, a channel (33) of one of the two fluid circuits, called the first circuit, and within each of the plates a channel (34) of the other of the two fluid circuits, called the second circuit. Figure for the abstract: Fig. 7A.

The present invention relates to a nuclear reactor loop capable of containing molten salt containing nuclear fuel in channels arranged substantially vertically and providing up and down flow paths. The loop can be used to build a modular reactor from removable individual molten salt nuclear loops, a portion of which ("channels") have been placed in a critical configuration in which the channels contain non-critical amounts of nuclear material, but together produce a critical region of a reactor core. The present invention further relates to a method of operating a modular nuclear reactor loop and nuclear reactor.

Disclosed are embodiments of a nuclear fuel element for use in various types of nuclear reactors. One embodiment of the nuclear fuel element comprises a plurality of solid nuclear fuel particles, such as tristructural-isotropic (TRISO) fuel particles, intermixed in a non-solid matrix that is substantially stagnant relative to the plurality of solid nuclear fuel particles. The non-solid matrix may comprise a liquid metal, a liquid metal alloy, and a liquid salt. Various embodiments of the non-solid matrix include tin, lead, sodium, aluminum, bismuth, and alloys thereof. A method of manufacturing a nuclear fuel and embodiments of a nuclear fuel core comprising the nuclear fuel element are also disclosed.