152results 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 masking element with an opening is disposed on the side of a core support structure. A flow stack wall defines a plurality of inlets. At least one inlet aligns with the masking element opening when the flow stack is mated with the masking element. A flow control assembly within the flow stack is configured to restrict flow of fluid within the flow stack.

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.

A curvilinear electromagnetic pump is configured to follow a curve, such as by joining together multiple linear pump segments offset at an angle relative to one another. A curvilinear electromagnetic pump can be curved in two dimensions or in three dimensions. A curvilinear electromagnetic pump allows for more efficient placement of components and systems within a reactor vessel, significantly reducing the height of the reactor vessel compared to vertically positioned linear pumps. A curvilinear electromagnetic pump can follow the curvature of the reactor vessel wall and can be positioned generally near the bottom of the reactor vessel.

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.

The present invention relates to a method of operating an MSR, said MSR comprising a reactor core, a fuel loop for molten fuel salt providing a flow path of molten fuel salt into the reactor core through a reactor core inlet and out of the reactor core through a reactor core outlet, said method comprising the steps of: providing at least one location mi on the fuel loop at a distance Li measured along the flow path from the reactor core outlet, wherein the one or more locations mi is outside the reactor core, and the one or more locations mi is shielded from the reactor core measuring the neutron source strength at the one or more locations mi obtaining one or more calculated operating parameters by calculation with input of the value of the measured neutron source strength at one or more locations mi.

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).

A method is used to design a nuclear reactor using design variables and metric variables. A user specifies ranges for the design variables and target values ​​for the metric variables. A set of design parameter samples is selected. For each sample, the method performs three processes to calculate metric variables for thermal-hydraulic, neutron, and stress. The method applies a cost function to each sample to calculate the ensemble residuals of the metric variables compared to the target values. The method trains a machine learning model using the samples and the calculated ensemble residuals. The method reduces the range of each design variable according to the correlation of the residuals estimated using each design variable and the machine learning model. These steps are repeated until the sample with the smallest residual remains constant over multiple iterations. The method then uses the final machine learning model to evaluate the relative importance of each design variable.

The present invention relates to a nuclear reactor, comprising a reactor vessel, a heat exchange device, a drive device, and a water supply device. The reactor vessel contains liquid coolant and an air cavity. The heat exchange device is disposed within the reactor vessel, wherein the inner wall forms a first cavity for accommodating a core, and the outer and inner walls together define a second cavity. One end of the drive device is connected to the air cavity, and the other end is disposed near the core. The water supply device is in communication with the second cavity. When the nuclear reactor is operating normally, the drive device causes the average density of the liquid coolant above the top of the core to be lower than the average density of the lower cavity below the core, thereby generating a gravity difference that drives the liquid coolant to circulate within the reactor vessel, transferring heat generated by the core. When the nuclear reactor malfunctions, the circulating cold source water in the water supply device circulates in the second cavity, continuously exchanging heat with the core to remove excess heat from the core. The present invention eliminates the need for a large main pump, reduces costs, and improves the safety and reliability of the nuclear reactor.

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 barrier material is used in a structural component of a nuclear reactor (10), the barrier material comprising molybdenum or a molybdenum-based alloy, wherein the barrier material has a molybdenum content of at least 90 wt.%, based on the total weight of the barrier material.

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.

The nuclear reactor (1) is a container (2) with a top closed by a roof (3) and accommodating a core (4), the core (4) comprising a bundle of fuel elements (5) and being immersed in a primary fluid (F) for cooling the core (4), the container (2), and a heat exchanger (40) for removing heat from the primary fluid (F) via a secondary fluid circulating within the heat exchanger (40), the core (4) being supported by a lower support (90) supporting the lower part of the core (4) below the active zone of the fuel elements (5) and by an upper support (80) supporting the upper part of the core (4) above the active zone of the fuel elements (5), the upper support (80) extending from the roof (3) and being joined to the roof (3) by a support structure (6) having an end element (16), the end element (16) having a central opening and being provided inside with a plurality of jaws (14) for vertical support and elastic radial restraint of the fuel elements (5).

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.

To provide a nuclear reactor with forced-convection liquid coolant and solid fuel assemblies, incorporating a heat removal system using a liquid metal bath for removing nominal heat and a phase-change material(s) (PCM) for removing decay heat in the event of an accident.SOLUTION: The present invention essentially relates to a solid-fuel nuclear reactor with a liquid metal or molten salt primary coolant, which simultaneously ensures, in particular: heat removal by forced convection in a primary circuit, in normal and accident operating modes, during shutdown through the primary vessel of the reactor, that is, beyond a second containment barrier; and implementation of a compact passive decay heat removal system capable of, in the event of an incident or accident, performing a safety function for a predetermined period, typically three days, by means of one or more PCMs that store decay heat produced in the core and removed by the primary vessel without any intervention by an operator.SELECTED DRAWING: Figure 3

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).

To provide a fast reactor core equipped with a gas expansion module, which can enhance the positive reactivity suppression effect even when assuming ULOF occurrence.SOLUTION: A fast reactor core equipped with a gas expansion module, a hollow tubular structure having one end open and the other end closed, is provided, the fast reactor core having a neutron absorber for absorbing neutrons or a neutron moderator for slowing down neutrons provided at a position adjacent to an outer side of the gas expansion module in a radial direction of the reactor core.SELECTED DRAWING: Figure 1

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.

The present invention relates to the technical field of lead-based reactors, and more particularly, to a nuclear energy storage integrated lead-based reactor with a load autonomous following function. The nuclear energy storage integrated lead-based reactor with a load autonomous following function includes a reactor core, a phase change energy storage device, and a heat energy utilization device; the reactor core is used to heat the coolant, and the heat energy utilization device is used to absorb the heat in the coolant; the phase change energy storage device is arranged on the inlet side of the reactor core, and the phase change energy storage device is used to interact with the coolant in terms of heat, and the phase change temperature of the phase change energy storage device is consistent with the preset inlet temperature of the reactor core. The nuclear energy storage integrated lead-based reactor with a load autonomous following function provided by the present invention has a natural circulation flow rate that is not easily oscillated and divergent, and the fuel assembly is not prone to the risk of overheating and melting, and the structural components are not prone to thermal fatigue, and has high safety performance.

A multipurpose passive residual heat removal system for a small fluoride-salt-cooled high-temperature reactor is provided, including: a circulation loop composed of a reactor body system, a multipurpose passive residual heat removal system, pipes and other connecting equipment between each system; wherein the reactor body system serves as the heat source of the system, using helical cruciform fuel element and FLiBe molten salt coolant, wherein a thermal power is 125 MW, and a temperature of the core outlet reaches 700° C., which has the advantages of high-temperature and low-pressure operation, inherent safety and compact structure. The multipurpose passive residual heat removal system not only serves as a special safety facility to ensure the passive safety of the reactor, but also efficiently recovers and utilizes the residual heat through the thermoelectric power generation device for power generation.