276results about "Fast fission reactors" patented technology

An integral molten salt nuclear reactor includes a drain tank section configured to hold a volume of fuel salt. The integral molten salt nuclear reactor further includes a reactor section configured to receive the volume of fuel salt from the drain tank and cause fission reactions that heats the molten salt. The integral molten salt nuclear reactor further includes a heat exchange section configured to receive a flow of the heated fuel salt from the reactor section and remove heat therefrom.

The present invention is directed to a fission product extraction system operable to capture and extract fission products from a flow of irradiated fueled molten salt of a molten salt reactor. The example extraction systems described herein utilize electroless deposition to chemically plate fission products onto a metallic structure. The metallic structure may be partially coated with a reducing agent, such as beryllium to provide an electron source for the fission products. The metallic structure may be a component of an extraction system designed to facilitate submersion of the metallic structure into the flow of molten salt. The extraction system may also be designed to facilitate removal of the metallic structure without requiring a shut down or slowdown of the reactor system.

The present invention relates to a method and system for predicting the evolution of helium bubbles in nuclear power system metal structural materials under irradiation, which belongs to the technical field of microstructure prediction of nuclear power system metal structural materials under irradiation conditions, and includes the steps of obtaining the chemical free energy density of the nuclear power structural material according to the vacancy formation energy, helium atom formation energy, gas constant, molar volume fraction and absolute temperature of the nuclear power structural material; The method includes: obtaining the elastic free energy density of the nuclear power structural material according to the elastic constant and elastic strain of the nuclear power structural material; and obtaining the diffusion coefficients of vacancies and helium atoms of the nuclear power structural material and the generation rate of helium atoms under irradiation according to the chemical free energy density and the elastic free energy density, thereby constructing a kinetic model based on the phase field equation to predict the evolution of helium bubbles in the nuclear power structural material under irradiation, thereby laying a more mechanistic theoretical foundation for the evolution of helium bubbles under irradiation conditions.

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.

The invention relates to the technical field of lead-based stacks, in particular to a nuclear storage integrated lead-based stack with a load autonomous following function. The nuclear storage integrated lead-based reactor with the automatic load following function comprises a reactor core, a phase change energy storage device and a heat energy utilization device, the reactor core is used for heating a coolant; the heat energy utilization device is used for absorbing heat in the coolant; the phase change energy storage device is arranged on the inlet side of the reactor core, the phase change energy storage device is used for carrying out heat interaction with a coolant, and the phase change temperature of the phase change energy storage device is consistent with the preset inlet temperature of the reactor core. According to the nuclear storage integrated lead-based reactor with the automatic load following function, natural circulation flow is not prone to oscillation and diffusion, the risk of overheating melting of the fuel assembly is not prone to occurring, thermal fatigue of the structural assembly is not prone to occurring, and high safety performance is achieved.

A mixed-spectrum molten-salt reactor has a primary containment vessel. A reactor core is housed in the primary containment vessel, the reactor core has an atypical geometry that holds a fuel salt. A blanket region is formed within the primary containment vessel and surrounding the reactor core, the blanket region comprises a blanket salt.

A containment system for an integral molten salt reactor includes a sealed containment structure defining a containment volume. The containment structure includes a fission product adsorbing / absorbing material. The containment system further includes an integral molten salt reactor housed fully within the containment volume of the sealed containment structure. The integral molten salt reactor may permit circulation of a fuel salt therein being heated by fission reactions, and allow for the export of heat from said fuel salt.

A containment system for an integral molten salt reactor includes a sealed containment structure defining a containment volume. The containment structure includes a fission product adsorbing / absorbing material. The containment system further includes an integral molten salt reactor housed fully within the containment volume of the sealed containment structure. The integral molten salt reactor may permit circulation of a fuel salt therein being heated by fission reactions, and allow for the export of heat from said fuel salt.

A reactor vessel that includes a reactor core mounted within a volume of the reactor vessel, the reactor core comprising one or more nuclear fuel assemblies configured to generate a nuclear fission reaction, a riser positioned above the reactor core, the riser forming a primary coolant flow path, a steam generator thermally coupled to the riser, the steam generator communicatively coupled to a steam turbine through a steam inlet that includes a steam inlet valve, a secondary coolant flow path that extends through the steam generator, the secondary coolant flow path coupled to a coolant pump, and a control system coupled to both the steam inlet valve and the coolant pump, the control system configured to control a power output of the nuclear fission reaction by adjusting one or more parameters of the steam inlet valve or the coolant pump.

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.

A nuclear reactor is configured with a primary coolant loop for transferring heat away from the nuclear reactor core. In a shutdown event, the primary coolant pump may stop pumping primary coolant through the reactor core, resulting in decay heat buildup within the reactor core. An inertial energy coast down system can store kinetic energy while the nuclear reactor is operating and then release the stored kinetic energy to cause the primary coolant to continue to flow through the nuclear reactor core to remove decay heat. The inertial energy coast down system may include an impeller and a flywheel having a mass. During normal reactor operation, the flowing primary coolant spins up the impeller and flywheel, and upon a shutdown event where the primary coolant pump stops pumping, the flywheel and impeller can cause the primary coolant to continue to flow during a coast down of the flywheel and impeller.

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 containment system for an integral molten salt reactor includes a sealed containment structure defining a containment volume. The containment structure includes a fission product adsorbing / absorbing material. The containment system further includes an integral molten salt reactor housed fully within the containment volume of the sealed containment structure. The integral molten salt reactor may permit circulation of a fuel salt therein being heated by fission reactions, and allow for the export of heat from said fuel salt.

To provide a fast reactor which includes an instrument for measuring neutron and enables facilitation of inspection and replacement of the instrument even when the instrument is failed.SOLUTION: This fast reactor S100 comprises: a reactor core 20 which houses a nuclear fuel; a main container 10; a roof slab structure 11; and a neutron detection unit 40 which measures a neutron flux of a neutron originated from a failed fuel of the reactor core 20. The neutron detection unit 40 has: a neutron guide tube 41 which extends in a height direction of the main container 10 in such a manner that the lower end side of the tube 41 is positioned within the main container 10, and the top end side penetrates through the roof slab structure 11; a moderator 43 which is arranged within the neutron guide tube 41, and decelerates a speed of the neutron; a neutron detector 44 which measures the neutron flux of the decelerated neutron; and an absorbent material 42 which is arranged below the moderator 43 within the neutron guide tube 41, absorbs a thermal neutron, and causes a delayed neutron to transmit the absorbent material 42.SELECTED DRAWING: Figure 1

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.

The invention relates to a nuclear reactor (1) having solid fuel assemblies (2) that are sealed and cooled individually in nominal operation by heat pipes (23). The invention substantially consists of a nuclear reactor (1) that operates in the fast neutron spectrum and is cooled by an array of one or more heat pipes (23). At least part of the evaporator (231) of one or more heat pipe(s) (23) is held and partially housed with one or more rods (22) of solid fuel pellets which are enclosed in a sheath in a sealed assembly which is partially filled with a liquid metal bath (21), which can be defined as a thermal seal between the rod sheaths and the heat pipes (23). The core (11) of the reactor (1) consists of an array of these sealed assemblies (2) (fuel rod(s) and heat pipe(s) immersed in a liquid metal bath) arranged within a tank (10) surrounded by a neutron reflector (12).

An extraction system includes an absorbent framework configured to withstand the harsh environment of a molten salt reactor system and capture fission products found in the molten salt of such systems. The extraction system further includes means for removing the absorbent framework from the flow of molten salt, such that the absorbent framework may be processed to harvest the fission products. The absorbent framework may include a temperature resistant cartridge configured to house an absorbent composition. The present invention contemplates multiple absorbent compositions including metal-organic frameworks with unique structures to provide thermal stability, carbon nanotubes, and absorbent microspheres. The metal-organic frameworks may be synthesized by a variety of techniques to impart particular characteristics advantageous for use in a molten salt reactor system.

A system for nuclear power generation includes an accelerator-driven subcritical reactor that operates using molten-salt fuel. The operation of the reactor can be continuously monitored to ensure subcriticality. The system also includes means for removing volatile radioactive fission products from the molten-salt fuel continuously during the operation of the reactor to maintain an amount of the volatile radioactive fission products in the reactor below a threshold corresponding to a safety limit for accidental release of radioactive materials. The system can be used for highly efficient nuclear power generation while preventing criticality accidents and accidental releases of radioactive isotopes.

To remove decay heat, and to prevent air and liquid metal from coming into contact with each other also in the event of double breakdown of a nuclear reactor vessel and a reactor containment vessel, and prevent occurrence of a fire disaster.SOLUTION: A nuclear reactor cooling system includes: a reactor core installed in a nuclear reactor vessel; a nuclear reactor cooling material filled in the nuclear reactor vessel; a reactor containment vessel containing the nuclear reactor vessel; a concrete silo housing the reactor containment vessel; a collector cylinder forming an air upflow passage and an air downflow passage in a space between the reactor containment vessel and the concrete silo, wherein air for cooling the reactor containment vessel, whose temperature has risen to a high temperature due to heat from the reactor containment vessel, flows upward and passes through the air upflow passage, and wherein ambient air descends, passes and is led to the air upflow passage in the air downflow passage communicating with the air upflow passage; a thermal insulation material installed so as to be in contact with an exterior side of the collector cylinder in a radial direction; and a liquid nitrogen supply system which is installed at an upper part of the concrete silo in order to supply liquid nitrogen to the air upflow passage and the air downflow passage.SELECTED DRAWING: Figure 2

Nuclear reactor systems and associated devices and methods are described herein. A representative nuclear reactor system includes a heat pipe network having an evaporator region, an adiabatic region, and a condenser region. The heat pipe network can define a plurality of flow paths having an increasing cross-sectional flow area in a direction from the evaporator region toward the condenser region. The system can further include nuclear fuel thermally coupled to at least a portion of the evaporator region. The heat pipe network is positioned to transfer heat received from the fuel at the evaporator region, to the condenser region. The system can further include one or more heat exchangers thermally coupled to the evaporator region for transporting the heat out of the system for use in one or more processes, such as generating electricity.

An integral molten salt nuclear reactor includes a drain tank section configured to hold a volume of fuel salt. The integral molten salt nuclear reactor further includes a reactor section configured to receive the volume of fuel salt from the drain tank and cause fission reactions that heats the molten salt. The integral molten salt nuclear reactor further includes a heat exchange section configured to receive a flow of the heated fuel salt from the reactor section and remove heat therefrom.

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, and any movement, such as through seismic forces, transmits an equal direction and magnitude to the control elements and the reactor core, thus inhibiting the opportunity for differential movement.

A plate-shaped nuclear fuel element includes a core made of a fissile material and a cladding. The cladding further includes a frame defining a central aperture receiving the core and two cover plates sandwiching the frame and the core. The frame is made of a metallic first cladding material. The cover plates are made of a metallic second cladding material. The first cladding material has a hardness strictly greater than the hardness of the second cladding material.

Molten salt nuclear fission reactor comprising a core through which a fuel salt flows, means (30, 31) for circulating the fuel salt, a primary heat exchanger through which a heat-transfer salt flows, a primary enclosure which is impermeable to liquid salts and contains the reactor core, and a shelter. The reactor comprises a parallelepiped matrix (10) comprising alternating layers (11) of fuel salt channels, and layers (12) of heat-transfer salt channels. The matrix forms both the reactor core, in which the fission occurs, and the primary heat exchanger of the reactor. The means for circulating the fuel salt are entirely located within the primary enclosure and are configured to extract the fuel salt from one portion of the fuel salt channels on one side of the matrix and to propel the fuel salt into the other portion of the channels on the same side of the matrix.

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 (1) comprises: a vessel (2) closed at the top by a cap (3) and containing a core (4) comprising a bundle of fuel elements (5) and immersed in a primary fluid (F) for cooling the core (4); and a heat exchanger (40) for removing heat from the primary fluid (F) by means of a secondary fluid circulating in the heat exchanger (40); the core (4) is supported by a lower support (90) supporting a lower portion of the core (4) below the active zone of the fuel elements (5) and an upper support (80) supporting an upper portion of the core (4) above the active zone of the fuel elements (5); the upper support (80) is joined to the top cover (3) by a support structure (6) extending from the top cover (3) and has an end element (16) which is open centrally and internally provided with a plurality of clamping elements (14) for vertically supporting and resiliently radially constraining the fuel element (5).

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.

The present invention relates to the field of nuclear power engineering, namely the placement of unsheathed fuel assemblies in a nuclear reactor core, aiming to improve the heat dissipation of fuel elements in a nuclear reactor. The nuclear reactor core comprises a hexagonal unsheathed fuel assembly having fuel elements located on a triangular grid with a spacing greater than the diameter of the fuel element cladding. The fuel elements comprise spiral spacer ribs on the cladding and are rigidly fixed in a given angular direction so that the fuel elements are in rib-to-rib contact at a height position at which the fuel elements reach the maximum fuel element cladding temperature during reactor operation. The fuel assembly is positioned in such a way that the fuel elements located on the surface of the fuel assembly form a single triangular grid with the remaining fuel elements in the core, and ensure that all the fuel elements are in rib-to-rib contact at a height position at which the highest fuel element cladding temperature is reached during reactor operation. At the same time, incorrect placement of the fuel assembly in the core is eliminated.

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 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.