55 results about "Neutron poison" patented technology

Disclosed is a coolant with dispersed neutron poison micro-particles, used in a supercritical water-cooled reactor (SCWR) emergency core cooling system. Since the neutron poison micro-particles are uniformly dispersed in the coolant of the emergency core cooling system for a long period time, their fluidity is not lowered even though the polarity of water is changed in a supercritical state. Therefore, the neutron poison micro-particles absorb neutrons produced from nuclear fission in a nuclear reactor core. Accordingly, the neutron poison micro-particles can be appropriately used as a means for controlling neutrons and stopping a nuclear reactor in the SCWR emergency core cooling system.

A zirconium alloy, comprising erbium as a burnable neutron poison, said alloy comprising, by weight:from 3 to 12% erbium;from 0.005 to 5% additional elements such as additives and / or manufacturing impurities;the remainder zirconium.A structural component comprising such a zirconium alloy.Processes for manufacturing and shaping the zirconium alloy by a powder metallurgy or a melting process.

A method is described for producing nuclear fuel products, including the steps of receiving metallic or intermetallic uranium-based fuel particle cores, providing at least one physical vapour deposited coating layer surrounding the fuel particle core and embedding the nuclear fuel particles in a matrix so as to form a powder mixture of matrix material and coated fuel particles. The at least one physical vapour deposited coating layer may include inhibitors of inhibiting, stabilizing and / or reducing interaction between metallic and intermetallic uranium-based fuel particles cores and the matrix wherein the fuel particles typically may be embedded. The deposited coating layer may include neutron poisons.

The invention relates to the critical safety control technologies of nuclear fuel reprocessing plant dissolvers, in particular to a critical safety control method for a dissolver with an annular solid neutron poison partition layout. The dissolver includes a big hanging basket disposed in a dissolver intramural dissolution solution. The big hanging basket is internally provided with a solid neutron poison partition structure, which comprises an annular neutron poison layer. The inner side and the outer side of the neutron poison layer are respectively provided with a poison outer coating shell and a poison inner coating shell, and the poison inner coating shell is internally provided with a neutron moderation material. The method provided by the invention improves the cross-sectional area and loading capacity of the reprocessing plant key technological equipment dissolver, and can solve the critical safety control problem of reprocessing plants.

The invention relates to a control technology of criticality safety in fissile substance solution storage tanks in a reprocessing plant and in particular relates to an arrangement structure of neutron poisons in a solution storage tank. The arrangement structure comprises the multiple neutron poisons which are arranged in the solution storage tank, wherein the cross sections of the multiple neutron poisons are cruciform, and each neutron poison extends along the height direction of the solution storage tank; a gap is reserved between each two adjacent neutron poisons; a piece of stainless steel cladding is arranged outside each neutron poison; the stainless steel cladding is filled with the neutron poisons. The two wings of each cruciform neutron poison are of a flat structure and can be adjusted to obtain the optimal thickness. Meanwhile, the reaction area between each neutron poison and a solution is enlarged, and a neutron absorption effect is obvious. The neutron poisons and the solution are isolated to be sealed, and thus possible loss of the neutron poisons is avoided.

The invention relates to a boron-untrusted controlling method for criticality safety of a spent fuel pool framework. Isolation regions are arranged around the spent fuel pool framework so as to prevent increase of reactivity caused by falling-off of a fuel assembly, and storage space of spent fuel assemblies is increased to reduce reactivity of a whole system. With such a technical scheme provided by the invention, under normal and credible accident working conditions, a spent fuel storage pool can realize high density storage in virtue of addition of solid neutron poison and combustion of trusted spent fuel assemblies while guaranteeing criticality safety, without trusting of soluble boron in water at the same time.

The invention provides an on-line removal device for pressurized water reactor fuel assembly fission gas. The device consists of a fuel assembly, an upper buffer container, a flow regulating valve, acirculation pump, a fission gas adsorption apparatus, a helium gas supply apparatus and a lower buffer container. The upper part of the fuel assembly is connected to the upper buffer container, the upper buffer container is connected to the flow regulating valve, the flow regulating valve is connected to the circulation pump, the circulation pump is connected to the fission gas adsorption apparatus, the fission gas adsorption apparatus is connected to the lower buffer container, the helium gas supply apparatus is connected between the fission gas adsorption apparatus and the lower buffer container, and the lower buffer container is connected to the bottom of the fuel assembly. In the pressurized water reactor running process, the on-line removal device provided by the invention can achieveon-line removal of fission gas generated in the fuel assembly, improve the thermal conductivity in the enclosure gap, reduce the neutron poison in the reactor running process, and enhance the economical efficiency of the reactor.

The invention belongs to the design of nuclear material reactive inhibition systems, in particular to a movable nuclear material reactive inhibition system suitable for accident condition. The system comprises a poison storage subsystem, a poison injection subsystem and a movable subsystem, wherein the poison storage subsystem is used for storing soluble gadolinium salt, unattached gadolinium-containing particles and attached gadolinium-containing particles; the poison injection subsystem is used for realizing poison dissolution and high-pressure or normal-pressure target injection; and the movable subsystem is used for transferring the system to a proper site, so that the availability and effectiveness of the system under the accident condition are improved. According to the system, effective neutron poisons can be provided for the system under the accident condition, and the system has enough subcritical depth.

The invention relates to a method for preparing fuel particles. The method comprises the steps: supplying a spherical core, performing formation of a porous silicon carbide layer or a zirconium carbide layer on the core through chemical vapor deposition so as to obtain porous silicon carbide layer / zirconium carbide layer-coated particles, soaking the porous silicon carbide layer / zirconium carbidelayer-coated particles in an active liquid for vacuum impregnation so as to obtain compound-filled porous silicon carbide layer / zirconium carbide layer-coated particles, and decomposing compounds which are filled in the compound-filled porous silicon carbide layer / zirconium carbide layer-coated particles so as to form combustible neutron-poison oxides or thorium oxide and finally obtain the fuel particles. The invention also provides core-shell fuel particles prepared by using the method. The fuel particle safety which is stack safety is improved through coating of the silicon carbide layer orthe zirconium carbide layer outside the core, and meanwhile the stack economy can be improved through the combustible neutron-poison oxides or thorium oxide filled in the silicon carbide layer or zirconium carbide layer.

The invention relates to a zirconium alloy containing erbium as consumable neutronic poison, wherein said alloy contains, in weight: 3 to 12 % of erbium; 0.005 to 5 % of additional elements such as additives and / or manufacturing impurities; the balance consisting of zirconium. The invention also relates to a structural part containing such a zirconium alloy, and to methods for manufacturing and shaping the zirconium alloy by sintering or fusion.

The invention discloses a spectrum calculation method of neutron noise in reactors based on the finite element theory. The method comprises following steps: performing geometrical processing on a processed nuclear reactor core based on the finite element theory; building a description equation of neutron noise in reactors based on the finite element theory; based on given frequency points, performing node scattering on the equation of neutron noise in reactors on a spatial grid and establishing a discrete node equation; establishing an overall equation according to a coefficient matrix and an equation source term of the discrete node equation assembly overall equation established in the third step; performing numerical calculation to obtain spatial distribution of neutron noise in reactors under given frequency points. Compared with the prior art, the positive effect of the invention is to realize the accurate calculation of the neutron noise spectrum of the reactor under complex geometries and to provide input conditions for reactor operation monitoring and troubleshooting and the method has significant implications for the progress of construction and safe operation of the reactor expert systems.

A method for shredding, blending, and packaging wastes so that the shipment of waste is acceptable for transportation and disposal. Containerized wastes, laden with fissile isotopes, such as that from sodium fluoride traps and granulated carbon collection assemblies, if not already conditioned, are conditioned for blending by shredding them to particle size and then blending the particles with a grout mix either in a reusable mixing vessel or in a disposable mixing vessel. The blend of waste and grout is selected to meet governmental and disposal site requirements for an acceptable waste shipment. If blended in a reusable vessel, the blended waste is transferred to shipping containers. The shipping containers are placed in shielded shipping casks for transportation to a disposal facility. The grout mix is a combination of grout and neutron poisons such as borated sand to prevent criticality.

The invention discloses a compact space reactor core structure suitable for passive starting. The compact space reactor core structure is composed of a fuel area and an external structure. The fuel area consists of a fuel rod, a control rod and a coolant; the fuel area is divided into an inner area and an outer area, and neutron poison with a certain mass fraction is dispersed in the fuel in the inner area and used for flattening radial power distribution; the fuel rod adopts high-concentration uranium dioxide fuel and a high-temperature-resistant molybdenum alloy cladding; the external structure is composed of radial reflecting layers, coolant channels and a source range detector which are alternately arranged, and the radial reflecting layers are used for reflecting neutrons leaked from a reactor core on one hand and acting with protons or alpha particles in a cosmic space to generate neutrons on the other hand when the reactor is started, so that the initial neutron fluence level is improved; sensitive 3He proportional counter tubes are selected as the source range detectors, and the four source range detectors are arranged on the inner side of the metal beryllium in a 90-degree symmetry mode in the radial direction. On the whole, the space reactor core has the characteristics of compact structure and convenience in monitoring.

The invention relates to a spent fuel storage cell. The storage cell sequentially comprises a neutron poison layer, a clamping layer and a support layer from inside to outside, wherein the neutron poison layer is a storage cavity (5) formed by four neutron poison boards (1) in an enclosed manner and used for placing a spent fuel component; the clamping layer comprises a hoop body (3) and a hoop strip (2) which are in butt joint, and the clamping layer is compressed to the outer side of the neutron poison layer; the support layer comprises two support plates (4) which are in butt joint, and the support layer is compressed to the outer side of the clamping layer. The spent fuel storage cell is good in rigidity, good in neutron capture ability, capable of guaranteeing the storage safety of the spent fuel component, simple in structure and easy to manufacture.

The invention discloses an Al-Nb-Zr-Mo-Hf-B system high-entropy alloy with neutron poison characteristics, and belongs to the field of high-entropy alloy materials. The Al-Nb-Zr-Mo-Hf-B system high-entropy alloy is prepared from the following components in percentage by mass: 5-15% of aluminum, 20-30% of niobium, 37-60% of zirconium, 4.99-15% of molybdenum, 1-20% of hafnium and the balance of boron (0.01-2%) and inevitable impurities. Aiming at the bottleneck problems that a conventional refractory high-entropy alloy of a typical BCC structure, such as TaNbMoW and TaNbMoWV, contains a large amount of high-density metal elements, is high in alloy density, high in cost and poor in room-temperature plasticity, and is difficult to use as a structural material, and the situation that the research on the high-entropy alloy with neutron poison characteristics is not fully paid attention to in original research, the high-entropy alloy based on the Al-Nb-Zr-Mo-Hf-B system is provided, the special effect of the element B is fully considered, and therefore structural function integration of the high-entropy alloy is achieved.

A pressurized water reactor (PWR) includes a pressure vessel containing a nuclear reactor core immersed in primary coolant water, control rod assemblies (CRA's), and control rod drive mechanisms (CRDM's) operating the CRA's. The reactor core has axially varying 235U enrichment and / or axially varying burnable poison concentration. A CRDM controller controls the CRA's over a burn-up cycle that does not include fuel assembly shuffling and is divided into a plurality of burn-up intervals. The CRDM controller is configured to, for each burn up interval: position the CRA's in accordance with a CRA pattern defining a set of fixed positions for the CRA's except for a sub-set of CRA's designated by the CRA pattern as floating CRA's, and control power level of the PWR by adjusting the floating CRA's without not adjusting the CRA's not designated as floating CRA's. The primary coolant water optionally does not contain soluble neutron poison.

The invention relates to an encapsulation particle and in particular relates to a neutron poison encapsulation particle with hot adhesion characteristics. The neutron poison encapsulation particle has a multi-layer shell structure, wherein a particle surface layer which can be shrunk and broken at high temperature is adopted as the outermost shell structure; a central area of the particle is provided with a particle poison core which has high-temperature gelling characteristics and is doped with a neutron poison; a particle middle cladding layer which is in a one-layer or multi-layer shell structure and has the high-temperature gelling characteristics is formed between the particle surface layer and the particle poison core. The neutron poison encapsulation particle can be carried and injected into a reactor core by a cooling agent through a special system under a severe accident condition that the reactor core of the nuclear reactor is melt down, so that the reactor core is deeply poisoned, and recriticality of the damage reactor core is completely avoided.

The invention belongs to the field of small-sized pressurized water reactor nuclear power plant accident treatment technology, and concretely relates to a rapid and safe reactor shutdown system of nuclear power plants. The system comprises two same systems, and each system comprises a transfer pump, a storage tank and a safety valve; a suction inlet of the transfer pump and the bottom of the storage tank are connected, an inlet of the safety valve and an outlet of the transfer pump are connected, the outlet of the safety valve is connected to the storage tank, and an outlet of the transfer pump is connected to a pressure vessel; the two systems are connected by a bridge pipe, and the bridge pipe is provided with a bridge pipe communicating valve. Outlet pipelines of the storage tanks are provided with filters. The system can be used for independently injecting a solution containing high-concentrated neutron poison in a reactor core, and the core is brought into a subcritical state and is kept at a certain subcritical degree.

The invention discloses a device for suspending a nuclear power station neutron poison sample, which comprises an upper tube socket, a lower tube socket, a plurality of support frame beams between the upper tube socket and the lower tube socket, and sample suspension grooves formed on the outer side of the support frame beams and fixedly connected with the support frame beams. When the nuclear power station is in service, the suspension samples can be placed in the suspension grooves of the device provided by the invention and can be periodically extracted for test detection, so as to judge whether the neutron poison material in spent fuel storage frameworks is effective or not, and periodically detect the neutron poison material in the spent fuel storage frameworks of a spent fuel storage water tank in a tracking manner; and the spent fuel storage frameworks falling short of requirements can be replaced or repaired according to the detection result, thereby ensuring the safety storage of the spent fuel components in the nuclear power station.

A pressurized water nuclear reactor (PWR) has an internal pressurizer volume containing a steam bubble and is surrounded by a containment structure. A condenser is disposed inside the containment structure and is operatively connected with an external heat sink disposed outside of the containment structure. A valve assembly operatively connects the PWR with the condenser responsive to an abnormal operation signal such that the condenser condenses steam from the steam bubble while rejecting heat to the external heat sink and returns the condensed water to the PWR. A quench tank contains water with dissolved neutron poison. A valved tank pressurizing path selectively connects the steam bubble to the quench tank to pressurize the quench tank, and a valved soluble poison delivery path selectively connects the quench tank to the PWR such that the quench tank under pressure from the steam bubble discharges water with dissolved neutron poison into the PWR.

The invention discloses a pressurized water nuclear reactor sleeve type standby shutdown system and method, the shutdown system comprises a sleeve type injection unit arranged in a pressure containerand a shutdown liquid circulation system arranged outside the pressure container, the sleeve type injection unit comprises an inner sleeve and an outer sleeve arranged on the outer side of the inner sleeve, the shutdown liquid circulation system comprises a soluble neutron poison box and a de-ionized water tank, the liquid discharging ends of the soluble neutron poison box and the de-ionized watertank are communicated with the outer sleeve through pipelines, circulating pumps are arranged on the pipelines, the liquid inlet end of the soluble neutron poison box and the liquid inlet end of thede-ionized water tank are communicated with the inner sleeve through pipelines, an outlet valve R1 and a return valve R 2 are respectively arranged on the pipelines of the liquid discharging end of the soluble neutron poison box and the liquid inlet end of the soluble neutron poison box, and an outlet valve W1 and a return valve W2 are respectively arranged on the pipelines of the liquid discharging end and the liquid inlet end of the de-ionized water tank. The shutdown system solves the problem that a liquid neutron absorber and a loop coolant are mixed due to the existing standby shutdown system.

The invention discloses a nitric acid corrosion resistant titanium-based neutron absorption material, which is composed of the following components in percentage by mass: 5-7% of Ta, 1-15% of Gd and the balance of Ti and inevitable impurities, the alloy utilizes the excellent corrosion resistance of titanium-tantalum alloy in nitric acid and the excellent neutron absorption performance of gadolinium element, and the corrosion resistance of the titanium-tantalum alloy in nitric acid is improved. The titanium-tantalum-gadolinium ternary solid neutron poison material with good nitric acid corrosion resistance is formed, so that the requirement of the spent fuel post-treatment industry for a corrosion-resistant neutron poison material is met, and in addition, the invention further provides a method for preparing the nitric acid corrosion-resistant titanium-based neutron absorbing material. According to the method, titanium-tantalum intermediate alloy scraps, gadolinium scraps and sponge titanium are mixed and then smelted, the nitric acid corrosion resistant titanium-based neutron absorbing material is obtained through a series of forging, rolling and heat treatment, and the prepared nitric acid corrosion resistant titanium-based neutron absorbing material not only has good mechanical properties, but also has good corrosion resistance. The neutron absorption capability and the nitric acid corrosion resistance are excellent.

The invention relates to an encapsulation particle and in particular relates to a neutron poison encapsulation particle with hot adhesion characteristics. The neutron poison encapsulation particle has a multi-layer shell structure, wherein a particle surface layer which can be shrunk and broken at high temperature is adopted as the outermost shell structure; a central area of the particle is provided with a particle poison core which has high-temperature gelling characteristics and is doped with a neutron poison; a particle middle cladding layer which is in a one-layer or multi-layer shell structure and has the high-temperature gelling characteristics is formed between the particle surface layer and the particle poison core. The neutron poison encapsulation particle can be carried and injected into a reactor core by a cooling agent through a special system under a severe accident condition that the reactor core of the nuclear reactor is melt down, so that the reactor core is deeply poisoned, and recriticality of the damage reactor core is completely avoided.

The invention discloses a fuel salt loop system and an operation method. The fuel salt loop system comprises a fuel salt pond and a reactor container. The fuel salt pond is divided into a first cavity used for containing fuel salt and neutron poison and a second cavity used for containing gas. The reactor container and the fuel salt pond form a fuel salt loop through a discharging system and a feeding system, and the bottom of the fuel salt loop is higher than the bottom of the second cavity; the feeding system comprises a reactor container inlet pipe arranged on the upper portion of the reactor container, and a main pump is arranged on the reactor container inlet pipe and used for driving fuel salt to flow into the reactor container from the fuel salt pond. The discharging system comprises a reactor container outlet pipe arranged at the bottom of the reactor container and a liquid level control pipe arranged on the reactor container. According to the invention, innovation is carried out on the design thought of the molten salt reactor, residual reactivity control and heat discharge are considered from the whole fuel salt loop system, the design of the reactor body is simplified, and the inherent safety is improved.

The invention relates to a critical experiment device and method for magnetically arranging neutron poison rods in a contactless manner. According to the method, the number and the arrangement mode ofneutron poison rods are selected through distributed top suction magnets on a top cover of a main body container, a hanging basket control module on the side surface of the main body container drivesa hanging basket to move along a rail, the selected neutron poison rod is vertically placed in the lower space of the device, after a critical experiment with the neutron poison rod is carried out, the hanging basket in the device is controlled to return to the upper space of the device, and the neutron poison rod is adsorbed and fixed in the upper space of the device again by the distributed topsuction magnet of the top cover of the device. According to the scheme, under the conditions of complete sealing and no contact, the arrangement scheme of neutron poison rods with rods, without rods,with different numbers, with different materials, with different arrangements and with different heights is realized, radioactive substances are prevented from leaking out of the critical experimentdevice to cause aerosol pollution and other radioactive hazards, and the critical experiment method is an advanced plutonium-containing fissile material solution system critical experiment technologywith engineering feasibility.