85results about "Subcritical reactors" patented technology

In a method of producing isotopes in a light water power reactor, one or more targets within the reactor may be irradiated under a neutron flux to produce one or more isotopes. The targets may be assembled into one or more fuel bundles that are to be loaded in a core of the reactor at a given outage. Power operations in the reactor irradiate the fuel bundles so as to generate desired isotopes, such as one or more radioisotopes at a desired specific activity or stable isotopes at a desired concentration.

A rod assembly for a fuel bundle of a nuclear reactor may include an upper end piece, lower end piece and a plurality of rod segments attached between the upper and lower end pieces and to each other so as to form an axial length of the rod assembly. The rod assembly may include an adaptor subassembly provided at given connection points for connecting adjacent rod segments or a given rod segment with one of the upper and lower end pieces. The connection points along the axial length of the rod assembly may be located where the rod assembly contacts a spacer in the fuel bundle. One (or more) of the rod segments may include an irradiation target therein for producing a desired isotope when a fuel bundle containing one (or more) rod assemblies is irradiated in a core of the reactor.

A nuclear-powered plant for systems of up to about 100 MWs with a confinement section where the reaction takes place in a core having a reactive thorium / uranium-233 composition, and where an external neutron source is used as a modulated neutron multiplier for the reactor core output. The core is housed in a containment structure that radiates thermal energy captured in a multiple-paths heat exchanger. The exchanger heat energy output is put to use in a conventional gas-to-water heat exchanger to produce commercial quality steam.

A process to safely convert about 95% of the nuclear waste into a usable fuel source is disclosed. The process, involving a sub-critical power reactor and a proliferation-resistant fuel cycle, consumes depleted uranium or thorium fuel with fissionable fuel, including reactor or weapons-grade plutonium. The reactor is comprised of coaxial neutron and energy-amplifying regions separated by moderating and thermal neutron absorbing layers. Control of the water or gas-cooled reactor is provided by plutonium-helium loops with a variable volume flow rate and an external source of neutrons that quickly reacts to any fluctuations of the reactor parameters. A second embodiment of the invention is a compact sub-critical propulsion reactor utilizing fission electric cell and thermo-acoustic technology for electrical power generation.

The invention discloses a liquid metal cooling reactor experimental system capable of realizing critical and subcritical running test. The liquid metal cooling reactor experimental system consists of a safety vessel (1), a main vessel (2), a reactor inner supporting structure (3), a reactor core (4), a central measuring column (5), a main heat exchanger (6), a reloading mechanism (7), a reactor top cover (8), a control bar drive mechanism (9) and a neutron source (10); when the critical running test is performed, the neutron source (10) adopts a californium-252 neutron source or a Be-Am neutron source; when the subcritical running test is performed, the neutron source (10) adopts a spallation neutron source or a deuterium tritium neutron source, an isotopic neutron source and a fuel component in the middle part of the reactor core are replaced by an accelerator neutron source according to the real requirement of the spallation neutron source, and the reactor can have the subcritical running test. The reactor experimental system is naturally and circularly cooled by adopting liquid lead-bismuth or lead, so that the usability of the reactor can be improved, the experimental cost can be reduced, and the multifunctional reactor experimental system characteristics can be achieved.

A combinatorial heterogeneous-homogeneous reactor configuration in which an array or groups of homogeneous fuel assemblies are interlinked together in a heterogeneous lattice. The present invention removes the limitation of a homogeneous reactor by providing a reactor concept that utilizes the inherent advantages of homogeneous fuel elements but in a heterogeneous fuel lattice arrangement that limits the power density of any one homogeneous fuel element and yet forms a reactor arrangement that is capable of producing any product demand of interest. The present invention provides a method for producing medical isotopes by the use of a modular reactor core comprised of homogeneous fuel assemblies arranged in a regular rectangular or triangular pitch lattice. The aqueous fuel solution is contained within individual fuel assemblies that are right circular cylinders clad in corrosion-resistant alloys such as stainless steel, zircalloy, zircalloy alloys, or other metal alloys that are resistant to corrosive fissile environments but preserve neutron economy. The fuel assemblies are supported below by a core plate that is tied directly to the lower reactor support structure. The bottom of each assembly opens into a common plenum area which provides a hydrodynamic communication / coupling path between the individual assemblies in the lattice. The fuel assemblies are supported above by an upper plate that is welded to each assembly tube. The top of each assembly opens to a common upper plenum which provides a means of thermodynamic pressure equalization among the four assemblies in the reactor core lattice.

A rod assembly for a fuel bundle of a nuclear reactor may include an upper end piece, lower end piece and a plurality of rod segments attached between the upper and lower end pieces and to each other so as to form an axial length of the rod assembly. The rod assembly may include an adaptor subassembly provided at given connection points for connecting adjacent rod segments or a given rod segment with one of the upper and lower end pieces. The connection points along the axial length of the rod assembly may be located where the rod assembly contacts a spacer in the fuel bundle. One (or more) of the rod segments may include an irradiation target therein for producing a desired isotope when a fuel bundle containing one (or more) rod assemblies is irradiated in a core of the reactor.

A nuclear-powered plant for systems of up to about 100 MWs with a confinement section where the reaction takes place in a core having a reactive thorium / uranium-233 composition, and where an external neutron source is used as a modulated neutron multiplier for the reactor core output. The core is housed in a containment structure that radiates thermal energy captured in a multiple-paths heat exchanger. The exchanger heat energy output is put to use in a conventional gas-to-water heat exchanger to produce commercial quality steam.

An accelerator-driven subcritical breeding reactor is operated with a neutron multiplication coefficient as large as possible in order to require a small input power from the accelerator, reducing its dimension and hence its cost and complexity. The beam-generated spallation neutron yield then becomes comparable to the fraction of delayed neutrons from the fissioned elements. This can be exploited to ensure an accurate on-line determination of the reactivity. Resulting changes can be adjusted with the help of neutron absorbing control rods and / or variations of the proton current. In addition, the temperature variations during operation can be continuously monitored and adjusted in order to avoid that the subcritical systems approaches too closely the (delayed) criticality condition and that the neutron multiplication coefficient remains within acceptable limits.

The present invention pertains to a method of controlling an accelerator coupled nuclear system comprising a nuclear reactor operating in subcritical mode and a neutron generator device using a beam of charged particles originating from an accelerator, said neutron generator supplying the quantity of neutrons necessary in order to maintain the nuclear reaction. Said method is characterized in that the operating point is determined by giving the energy Ep of the particles a value greater than or equal to the value EPMax, which maximizes the production of neutrons, and in that the number of neutrons is adjusted by acting on the energy of the particles originating from the accelerator, with constant beam intensity. The present invention also pertains to the accelerator coupled hybrid nuclear system used for same.

A radiocactive waste containing medium is circulated within two or more systems (1,2,3) separated from each other flowtechnically; and the circulated radioactive waste is exposed to neutron radiations of different energy spectrum in each system by operating a reactor physically united entirety of irradiated sections of the said systems as a nuclear reactor or an accelerator driven subcritical system. Each system (1,2,3) has a heat exchanger (9,10) and, in given cases, a circulating pump (10,21) and an expansion tank (5,16,27). The disclosed apparatus has two or more reactor regions (1,2,3) separated from each other by partitions (37,38) and, preferably, arranged coaxially within a reactor space encircled by a common shell structure (39). A particle beam (45) produced by a particle accelerator is preferably directed into the innermost reactor region (3).

The invention discloses a deep negative feedback transmutation reactor core based on accelerator driven subcritical clean nuclear energy system and belongs to the field of nuclear reactors. The reactor core comprises a target area (A), a quick spectrum area (B) and a deep negative feedback area (C). According to the deep negative feedback transmutation reactor core provided by the invention, the problem that the reactor is instable in power because the accelerator beam is instable under the conventional technical conditions can be solved, the reactor can stably operate under different subcritical depths, and the reactor has extremely high inherent safety due to a large fuel Doppler coefficient.

The present invention relates generally to an apparatus of assembling a capsule for neutron-irradiation experiments. The capsule may contain test specimens to develop nuclear fuel, and may comprise a capsule main body and protection tube that may be assembled and disassembled using separate joining means. The present invention provides a capsule assembling apparatus that may enable safe and easy assembly / disassembly of the capsule placed at a given depth in a working pool through remote working. The capsule assembling apparatus may comprise a base structure loading the capsule main body, a guiding pipe of a given length extending from the base structure to provide a pathway through which the capsule main body is loaded on the base structure, a damper fixing the capsule main body to the guiding pipe, and a coupler coupling the capsule main body with the protection tube.

Various embodiments of a transportable nuclear power generator having a plurality of subcritical power modules are disclosed. Each of the plurality of subcritical power modules includes a fuel cartridge, a power conversion unit, and a housing substantially enclosing the fuel cartridge and the power conversion unit. The fuel cartridge contains a nuclear fuel and has a proximal end and a distal end. The power conversion unit includes a compressor turbine disposed at the proximal end of the fuel cartridge and a power turbine disposed at the distal end of the fuel cartridge. At least one of the plurality of subcritical power modules is movable with respect to the other of the plurality of subcritical power modules between a first position and a second position to control criticality of the nuclear fuel contained in the fuel cartridges of the plurality of subcritical power modules.

A nuclear-powered plant of a portable type with a confinement section where the reaction takes place in a core having a reactive thorium / uranium-233 composition, and where an external neutron source is used as a modulated neutron multiplier for the reactor core output. The core is housed in a containment structure that radiates thermal energy captured in a multiple-paths heat exchanger. The exchanger heat energy output is put to use in a conventional gas-to-water heat exchanger to produce commercial quality steam.

The invention discloses a molten salt depleted uranium reactor, belonging to the technical field of molten salt reactors; fast neutron spectrum, chloride molten salt, uranium plutonium cycle and depleted uranium are used; after start, only by use of a nuclear fuel of self proliferation, long-term stable and safe operation can be achieved, and a supercritical accident may not happen; negative feedback can keep in the critical state; the entire uranium plutonium cycle can be completed in the reactor; normal operation only requires the use of the depleted uranium, the reactor itself does not need uranium enrichment and purification; and high burnup of the depleted uranium can be realized. The reactor has the advantages of simple structure and easy operation, is very suitable for large-scale popularization and application. The reactor is applicable to various types of molten salt formulas and structure materials. The technology, complete set of system technology, engineering and industrialization are feasible. The preferred system is as follows: simplified low temperature IV type + 316 stainless steel main container + nitrogen coolant + 318 stainless steel pipeline pump heat exchanger and the like. Fission nuclear energy can be used to fully meet the national long-term energy needs, at the same time, the problems of the shortage of uranium resources, nuclear criticality safety and low carbon development can be solved, and the reactor is mainly used for heat, electricity or mechanical power supply.

The invention provides a double-reactor-core zero-power device comprising a water reactor ad a lead reactor, the water reactor comprises a first fuel element, a first reactor core, a first control rodsystem and a water circuit system, the first reactor core is a pool structure, and is connected with the first control rod system and the water circuit system, the first fuel element is used for a nuclear fuel in the first reactor core, the first control rod system is used to control the first reactor core for zero power experiments, and the water circuit system is used for supplying deionized water to the first reactor core; the lead reactor comprises a first fuel element, a second fuel element, a second reactor core, a second control rod system and a safety block system, the second reactorcore is coupled to the second control rod system and the safety block system, the first fuel element and the second fuel element are used for a nuclear fuel in the second reactor core, and the secondcontrol rod system and the safety block system are used to control the second reactor core for zero power experiments. The device has the characteristics of being inherent in safety, flexible and variable in reactor core loading, convenient in operation, stable and reliable, accurate in measurement and good in repeatability.

A nuclear-powered plant for systems of up to about 100 MWs with a confinement section where the reaction takes place in a core having a reactive thorium / uranium-233 composition, and where an external neutron source is used as a modulated neutron multiplier for the reactor core output. The core is housed in a containment structure that radiates thermal energy captured in a multiple-paths heat exchanger. The exchanger heat energy output is put to use in a conventional gas-to-water heat exchanger to produce commercial quality steam.

A redundant, low cost accelerator driven system for power generation or waste treatment. The system generates fission from fertile nuclear materials and includes multiple charged particle sources, nested redundancy of low energy accelerator sections for reliability, and multiple subcritical reactors. Merging and splitting devices based on radiofrequency transverse kickers enable the nested redundancy. A control system provides RF buckets with identifiers, enabling the control of charged particles on an RF bucket basis through the accelerator, for the delivery to a desired subcritical reactor of a desired number of RF buckets of such predetermined characteristics to generate a desired reactor power. Consequently, the power level of each reactor may be controlled independently even though a large part of the high power accelerator system is used to feed multiple reactors simultaneously.

A spallation device for production of neutrons includes a solid spallation target that produces neutrons by interaction with a hollow particle beam propagating within a first chamber, a second chamber containing the spallation target, and a leak tight partition separating the first and second chambers.

A process incinerate transuranic chemical elements and nuclear reactor implement this process. In order to incinerate transuranic chemical elements, such as long-lived nuclear waste and plutonium, a nuclear reactor is used in which the core operates at a low level of sub-criticality. This level is chosen substantially equal to the difference βs between a desired fraction βt of delayed neutrons in the core and the real fraction β. An external source of spallation neutrons includes a proton accelerator in which one adjusts the power, in real time, on the neutron flux measured in the core. A supplementary fraction of delayed neutrons equal to the difference βs is thus injected into the reactor core. The reactor then behaves and controls itself like a classical critical reactor.

A combinatorial heterogeneous-homogeneous reactor configuration in which an array or groups of homogeneous fuel assemblies are interlinked together in a heterogeneous lattice. The present invention removes the limitation of a homogeneous reactor by providing a reactor concept that utilizes the inherent advantages of homogeneous fuel elements but in a heterogeneous fuel lattice arrangement that limits the power density of any one homogeneous fuel element and yet forms a reactor arrangement that is capable of producing any product demand of interest. The present invention provides a method for producing medical isotopes by the use of a modular reactor core comprised of homogeneous fuel assemblies arranged in a regular rectangular or triangular pitch lattice. The aqueous fuel solution is contained within individual fuel assemblies that are right circular cylinders clad in corrosion-resistant alloys such as stainless steel, zircalloy, zircalloy alloys, or other metal alloys that are resistant to corrosive fissile environments but preserve neutron economy. The fuel assemblies are supported below by a core plate that is tied directly to the lower reactor support structure. The bottom of each assembly opens into a common plenum area which provides a hydrodynamic communication / coupling path between the individual assemblies in the lattice. The fuel assemblies are supported above by an upper plate that is welded to each assembly tube. The top of each assembly opens to a common upper plenum which provides a means of thermodynamic pressure equalization among the four assemblies in the reactor core lattice.

Incineration process for transuranic chemical elements and nuclear reactor implementing this process. In order to incinerate transuranic chemical elements, such as long-lived nuclear waste and plutonium, a nuclear reactor is used in which the core (12) operates at a low level of sub-criticality. This level is chosen substantially equal to the difference betas between a desired fraction betat of delayed neutrons in the core and the real fraction beta. An external source of spallation neutrons includes a proton accelerator in which one adjusts the power, in real time, on the neutron flux measured in the core (12). A supplementary fraction of delayed neutrons equal to the difference betas is thus injected into the reactor core. The reactor then behaves and controls itself like a classical critical reactor.

The invention relates to a reactor core structure and a control manner of a start-stop reactor thereof. The reactor core structure comprises a fixed fuel component, a mobile fuel component, and a drive mechanism, wherein the fixed fuel component comprises a plurality of first fuel rods that are arranged side by side, the plurality of first fuel rods form a guide hole after being arranged, and a guide cylinder for guiding the mobile fuel component is arranged in the guide hole; the mobile fuel component comprises a plurality of second fuel rods that are arranged side by side, the mobile fuel component can move between a first position and a second position in an axial direction so as to match with the guide cylinder, when the mobile fuel component is at the first position, the mobile fuel component is inserted into the guide hole, when the mobile fuel component is at the second position, the mobile fuel component leaves the guide hole; and the drive mechanism is matched with the mobilefuel component and provides the mobile fuel component with a driving force that enables the mobile fuel component to move toward the first position, and the mobile fuel component also can move to reset at the second position, so that a small reactor core can be conveniently controlled to start and stop.

The invention discloses a novel ring-cavity multifunctional nuclear system, comprising a neutron source and a reactor; the neutron source is of cylindrical pipe structure, the center of the reactor is of ring cavity structure, the neutron source is extended through the center ring cavity of the reactor and fixed outside the reactor, a core is arranged in the reactor and around the wall of the center ring cavity of the neutron source, the core is radially supported by inner and outer barrels, the reactor is provided with an internal member, a diversion passage is formed between the internal member and the wall of the ring cavity, and the reactor has an independent reactor-target coupling boundary and is able to be compatible with various neutron source systems; the neutron source and the reactor do not share a common coolant boundary, and the requirement of structural materials for the compatibility of coolants is lowered; no liquid environment is provided outside the neutron source, and structural replacement reliability of the neutron source system is improved. By designing the inner and outer barrels for the reactor and using the coolant diversion scheme, the ring-cavity structure core fixation problem and the coolant stagnation problem are solved, and the safety of the reactor is improved.

The invention discloses a sub-critical miniature reactor driven by neutron tubes. The sub-critical miniature reactor comprises fuel rods, the neutron tubes, a coolant, cladding tubes, a reflecting layer, a shielding layer and other ingredients, wherein the neutron tubes are taken as neutron sources for operation of a sub-critical miniature reactor and are uniformly dispersed and distributed in a sub-critical reactor core, and the neutron-flux density distribution of the reactor core is initiatively flattened in design. The quantity of neutrons output by each neutron tube in the reactor core in unit time can be continuously adjusted, so that power in each position in the reactor can be continuously adjusted, and the output power in each position of the reactor core is actively controlled. Under the accident condition, a power supply for the neutron tubes can be turned off at any time as required, reactor shutdown is completed, and serious accidents are completely eradicated. Due to the advantages, the reactor has high safety and economic performance and has great significance in improvement of geometric dimension miniaturization and maneuverability of the reactor.

An accelerator-driven subcritical breeding reactor is operated with a neutron multiplication coefficient as large as possible in order to require a small input power from the accelerator, reducing its dimension and hence its cost and complexity. The beam-generated spallation neutron yield then becomes comparable to the fraction of delayed neutrons from the fissioned elements. This can be exploited to ensure an accurate on-line determination of the reactivity. Resulting changes can be adjusted with the help of neutron absorbing control rods and / or variations of the proton current. In addition, the temperature variations during operation can be continuously monitored and adjusted in order to avoid that the subcritical systems approaches too closely the (delayed) criticality condition and that the neutron multiplication coefficient remains within acceptable limits.

Disclosed are apparatus and method of providing accurate control of a nuclear reactor containing fuel and designed to be subcritical in the static case that has a vessel, the vessel defining a shell, and an internal volume containing the fuel. A fusion target is located in the internal volume and contains a reactive material. A pulsed source of a hydrogen isotope directs the hydrogen isotope into, but stopping within the fusion target. Each pulse of a hydrogen isotope produces a pulse of neutrons from the reactive material in the fusion target that scatter into and burn the fuel, and thereafter the reactor returns to the static case.

The present invention relates to a transportable nuclear power generator by means of modular components fully sealed that form a critical and super-critical system when assembled at a deployment site for the purpose of safely generating electric power without requiring site infrastructure. In particular, the present invention relates generally to transportable and distributable electric power and process heat generation by means of a micro modular, compact, transportable, inherently safe nuclear generator deployable and retrievable within a few hours from reactor shut-down, comprising power conversion and conditioning for remote electric generation via combined Brayton and Rankine power cycles.

An aqueous assembly has a negative coefficient of reactivity with a magnitude. The aqueous assembly includes a vessel and an aqueous solution, with a fissile solute, supported in the vessel. A reactivity stabilizer is disposed within the aqueous solution to reduce the magnitude of the negative coefficient of reactivity of the aqueous assembly during operation of the aqueous assembly.