33 results about "Neutron moderator" patented technology

The invention discloses a fast thermal neutron and gamma ray multi-mode detector, and relates to the technical field of nuclear radiation detection, and the detector comprises a detector housing, and the interior of the detector housing is connected with a fast neutron detection unit, a thermal neutron detection unit and a gamma ray detection unit. The gamma ray detection unit is located between the fast neutron detection unit and the thermal neutron detection unit; and an insulating separation unit is connected between two adjacent detection units. The detector can detect fast neutrons, thermal neutrons and gamma rays in the same equipment at the same time, structures such as a cadmium thermal neutron shielding layer and a fast neutron moderation layer do not need to be added, the size of the detector can be greatly reduced, and the detector has the advantages of being compact in structure, stable in performance, wide in energy measurement range, wide in fluence rate measurement range and the like. The ultrahigh-energy high-flux neutron measurement with the neutron energy at least covering # imgabs0 # and the neutron fluence rate at least covering # imgabs1 # can be realized.

A radioisotope production capsule is described. Each capsule includes generally an inner container for housing one of a target material and a neutron moderator, an outer container surrounding the inner container for housing the one of the target material and the neutron moderator not housed by the inner container, and cladding for isolating the target material from the neutron moderator. One or more modular capsules are placed in each of a plurality of plug fingers. Each single plug finger loaded with one or more capsules is inserted into a guide thimble of an array of guide thimbles in a fuel assembly.

The invention provides a doped yttrium hydride neutron moderation material and a preparation method and application thereof, and belongs to the technical field of radiation shielding materials. At least one of samarium, europium and gadolinium is doped in yttrium hydride in the form of hydride, and the mass ratio of metal yttrium to metal gadolinium to metal europium to metal samarium is controlled, so that the neutron moderation effect of the neutron moderation material can be improved. According to the invention, at least one of gadolinium hydride, europium hydride and samarium hydride is mixed with yttrium hydride under the protective atmosphere, so that the mass content of each element in the doped yttrium hydride neutron moderation material can be accurately controlled. According to the invention, the mixture is sintered and molded, and the sintering parameters of sintering and molding are controlled, so that the components of the mixture are sintered in a compact state, cracks generated by thermal expansion and cold contraction can be reduced, and the doped yttrium hydride keeps high density and has fewer cracks and defects.

The invention relates to a moderator of a compact single-ball neutron spectrometer, and the moderator is characterized in that an inner layer is of a cylindrical structure, and a plurality of thermal neutron detectors are installed in the inner layer; the thermal neutron absorption layer sleeves the outer side of the inner layer and is made of boron-containing polyethylene; the scattered neutron moderation layer sleeves the outer side of the thermal neutron absorption layer; the inner layer comprises a detector placing block and a thermal neutron absorption block, and the thermal neutron absorption block is provided with a storage groove; a plurality of thermal neutron detectors are placed in the detector placement block along the axis direction, the first thermal neutron detector is placed in the storage groove, and the thermal neutron absorption block is made of boron-containing polyethylene; the diameter of the inner layer is 8 cm, the outer diameter of the thermal neutron absorption layer is 14 cm, and the outer diameter of the scattered neutron moderation layer is 20 cm. The purposes that the size is controlled by controlling the diameter of the cylindrical structure and the scattering shielding effect is enhanced by arranging the three layers of moderator structures in a sleeving mode are achieved, and therefore the technical effects that the moderator is small in size, convenient to transport and high in scattering shielding effect are achieved.

The invention relates to a personal dosimeter for neutron and photon mixed radiation detection and a detection method, the dosimeter comprises a base, an upper cover and three groups of detection assemblies, and the base is provided with three grooves which are distributed in parallel and respectively accommodate a first detection assembly, a second detection assembly and a third detection assembly. The first detection assembly and the second detection assembly each comprise a neutron absorber with grooves formed in the upper portion and the lower portion and a 6Li thermoluminescence detector pair and a 7Li thermoluminescence detector pair, and separated measurement of the dose of thermal neutrons, medium-high energy neutrons and gamma rays is achieved. The third detection assembly comprises a neutron moderator and a solid track detector. Separation measurement of neutrons with different energies is realized through track density difference. The upper cover is provided with a measuring window, and tissue equivalent materials with different mass thicknesses are adopted and correspond to the dose depth of Hp (10) and the dose depth of Hp (3). Through combination of multi-channel reading and correction coefficient calculation, dose evaluation of gamma rays, thermal neutrons and fast neutrons on different tissue depths can be realized. The device is compact in structure, and is suitable for personal dose monitoring in a complex radiation environment.

The invention discloses a neutron gamma detector with a high dynamic range and time resolution. The neutron gamma detector comprises a plurality of layers of detection units, a plurality of neutron moderation bodies and a detector shell, each detection unit is arranged along the axis of the detector shell, a neutron moderator is arranged between every two detection units, each detection unit comprises a neutron / gamma sensitive scintillator array, a photomultiplier array and a pre-amplifier array, and each layer of neutron / gamma sensitive scintillator array is matched with one layer of photomultiplier array and one layer of pre-amplifier array. According to the detector, multiple layers of neutron slowing-down bodies are utilized to form gradients of neutron and gamma ray detection efficiency of each layer of scintillators, and a pulse counting matrix can be measured and obtained after the neutron / gamma sensitive scintillator array is matched with the photomultiplier tube array and the pre-amplifier array. And then neutron and gamma counting rates at each layer of detector are extracted. Meanwhile, based on the structural design of the detector, the time resolution and the dynamic range are improved.

The invention provides a wide-energy-spectrum neutron dose rate meter, and the meter comprises a mechanical structure assembly which comprises a proportional counter tube, a neutron moderator layer, and a neutron multiplier layer; wherein the neutron moderator layer wraps the proportional counter tube, and the neutron multiplier layer is arranged between the neutron moderator layer and the proportional counter tube; and the circuit board is used for providing working voltage for the proportional counter tube and processing a detection signal output by the proportional counter tube.

The invention provides an yttrium hydride material containing a hydrogen permeation resistant coating and a preparation method of the hydrogen permeation resistant coating, and the method comprises the following steps: adding an aluminum salt and a chromium salt into a mixed solvent containing an alcohol substance, and after stirring reaction and aging treatment, preparing an aluminum oxide and chromium oxide composite sol-gel system; immersing the cleaned yttrium hydride matrix into the aluminum oxide and chromium oxide composite sol-gel system, and forming a composite sol-gel film layer on the surface of the yttrium hydride matrix by adopting a dip-coating method; the yttrium hydride matrix containing the composite sol-gel film layer is subjected to roasting treatment, so that the composite sol-gel film layer is converted into a compact hydrogen permeation resisting coating; the raw materials forming the coating are prepared into a sol system, the hydrogen permeation resisting coating is formed on the surface of the yttrium hydride matrix in a dip-coating and roasting mode, the yttrium hydride material containing the hydrogen permeation resisting coating is applied to a small nuclear reactor and used as a neutron moderator, and the service time of the yttrium hydride material can be effectively prolonged.

The invention discloses a high-temperature-resistant yttrium-gadolinium hydride neutron moderation absorber and a manufacturing method thereof, and belongs to the field of nuclear power. The manufacturing method of the high-temperature-resistant yttrium-gadolinium hydride neutron moderation absorber comprises the following steps: performing pre-hydrogenation treatment on yttrium powder and gadolinium powder, uniformly mixing the yttrium powder and the gadolinium powder to obtain mixed powder, performing cold press molding on the mixed powder, and then performing hydrogenation sintering to obtain the high-temperature-resistant yttrium-gadolinium hydride neutron moderation absorber. According to the method, the cracking risk of the neutron moderation absorber in the sintering process can be effectively reduced, and the neutron moderation absorber with good fast neutron moderation performance and thermal neutron absorption performance is prepared.

The invention relates to a combined cold and thermal neutron moderator (10) having a longitudinal axis (t) and at least one neutron exit window (50) at a first end (11, 12), and a cold moderator (20) arranged along the longitudinal axis (t), a thermal pre-moderator (30) and a vacuum space (40), said thermal pre-moderator (30) having a pre-moderator mantle (32) surrounding the cold moderator (20) along the longitudinal axis (t) and separated from the cold moderator (20) by the vacuum space (40), characterized in that the pre-moderator (30) comprises a pre¬moderator collar (34) extending at least at the first end (11, 12) from the pre¬moderator jacket (32) towards the longitudinal axis (t), which substantially covers the portion of the vacuum space (40) between the cold moderator (20) and the pre¬moderator mantle (32) from the direction of the neutron exit window (50), leaving substantially free at least one end (21, 22) of the cold moderator (20) at the end (11, 12).WO

A radioisotope production capsule is described. Each capsule includes generally an inner container for housing one of a target material and a neutron moderator, an outer container surrounding the inner container for housing the one of the target material and the neutron moderator not housed by the inner container, and cladding for isolating the target material from the neutron moderator. One or more modular capsules are placed in each of a plurality of plug fingers. Each single plug finger loaded with one or more capsules is inserted into a guide thimble of an array of guide thimbles in a fuel assembly.

The present invention provides a system for testing the comprehensive performance of microstructured neutron detectors. The system comprises a neutron moderator, the front side of which is equipped with a mixed radioactive source and a switchable gamma shield. A standard neutron detector, a silicon-based microstructured neutron detector, and a standard gamma detector are housed within the neutron moderator, wherein the silicon-based microstructured neutron detector is placed in a constant temperature chamber. Each of the standard neutron detector, silicon-based microstructured neutron detector, and standard gamma detector is connected to a front-end electronic device, each of which is connected to a multi-channel counter. The present invention conducts radiation performance testing on a developed silicon-based microstructured neutron detector chip prototype system, including thermal neutron detection efficiency, n / gamma discrimination ratio, applicable temperature range, and count rate, thereby filling a gap in the testing of three-dimensional silicon-based neutron detectors.

The application discloses a neutron gamma detector with high dynamic range and time resolution, comprising: a plurality of layers of detection units, a plurality of neutron moderators and a detector shell; each detection unit is arranged along the axis of the detector shell, and a neutron moderator is arranged between each detection unit; the detection unit comprises a neutron / gamma sensitive scintillator array, a photomultiplier tube array and a preamplifier array, and each layer of neutron / gamma sensitive scintillator array is matched with one layer of photomultiplier tube array and one layer of preamplifier array. The detector utilizes the multiple layers of neutron moderators to form the gradient of the neutron and gamma ray detection efficiency of each layer of scintillator, the neutron / gamma sensitive scintillator array matched with the photomultiplier tube array and the preamplifier array can measure and obtain a pulse count matrix, and then the neutron and gamma count rate at each layer of detector can be extracted. Meanwhile, the time resolution and dynamic range are improved based on the structural design of the detector.

The invention discloses a composite neutron slowing-down material, and relates to the technical field of composite neutron slowing-down materials, the composite neutron slowing-down material comprises a composite hydrogen-containing material and fluoride.The preparation process comprises the steps that the hydrogen-containing material is smashed and screened to obtain particles with specific granularity, and the particles are mixed and dispersed with dried fluoride particles; adsorbing the fluoride on the surface of the hydrogen-containing material through mechanical stirring; carrying out melting treatment on the mixed material, melting the hydrogen-containing material to form a continuous phase, and uniformly dispersing fluoride particles under the action of shearing force and combining with a macromolecular chain through weak interaction; after the molten material is injected into a mold, heat preservation forming is conducted at the specific temperature, and annealing treatment is conducted to eliminate internal stress after cooling demolding. By regulating and controlling the particle size of the hydrogen-containing material, the hydrogen / fluorine mass ratio and the forming heat preservation temperature, uniform distribution of hydrogen atoms in the material, interface bonding strengthening and inhibition of fluoride on thermal degradation are achieved, so that the neutron moderation efficiency, the tensile strength and the thermal stability of the material are improved, and the material is suitable for neutron protection scenes in the nuclear industry.

A fuel rack for wet storage of nuclear fuel in a fuel pool comprises, in one embodiment, a base plate and a cellular body formed from slotted plates bonded to each other and stacked, coupled to the base plate. This cellular body comprises densely packed, upward-opening cells, each holding a nuclear fuel assembly. When the rack is submerged in water, open flax straps are formed between at least some of the water-filled cells, acting as neutron moderators to control the reactivity within the rack. In one embodiment, flax straps are interspersed between adjacent cells in a first direction along a first horizontal axis of the rack. However, flax straps are not interspersed between adjacent cells in a second direction perpendicular to a second horizontal axis. Other flax strap and cell arrangements are also provided. Tension elements penetrate some of the flax straps, and these tension elements compress the stack of plates to ensure stability.

The application belongs to the technical field of boron neutron capture therapy of tumors, and relates to an interventional boron neutron capture therapy device. The interventional boron neutron capture therapy device comprises a neutron generator, a neutron moderator and a neutron export injector. The neutron generator is used for generating neutrons by bombarding a target material with an incident high-energy particle beam. The neutron moderator is connected to the neutron generator and is used for slowing down the neutrons generated by the neutron generator into thermal neutrons and shielding gamma rays generated in the slowing down process. The neutron export injector is connected to the neutron moderator and is used for guiding and transporting the slowed-down thermal neutrons to a treatment site in a patient's body. Thus, the problem that the neutron transport scheme in the prior art cannot effectively balance neutron utilization rate, treatment depth and additional radiation damage borne by a patient can be solved.

A reactor control system for a nuclear reactor, the reactor control system comprising: one or more hollow tubes comprising neutron absorbing material, each having a first end and a second end; a pump connected to the first end of each hollow tube and operable to control the amount of a first fluid within the hollow tube, the first fluid comprising a neutron moderator, wherein: the pump is controlled based on a level of reactivity in the nuclear reactor, and the second end of the hollow tubes is in fluid communication with a second fluid, the second fluid having a neutron moderating capacity lower than 10% of that of the first fluid.

The present invention discloses an application of an anti-neutron radiation optical fiber and a high-hydroxyl photocurable resin. The optical fiber includes: an optical waveguide structure, and a multi-layer cladding covering the optical waveguide structure; the thickness of the multi-layer cladding is 27.5 to 106.5 μm; the multi-layer cladding contains a fast neutron moderator and a thermal neutron absorber; the fast neutron moderator is covalently bonded hydrogen, and the thermal neutron absorber is a compound containing a neutron absorbing element, and the neutron absorbing element includes boron and rare earth elements; wherein: the average molar concentration of hydrogen element is 67.28 to 112.9 mol / L; the average molar concentration of the neutron absorbing element is 0.4 to 2.8 mol / L. The high-hydroxyl photocurable resin is applied to form the coating of the optical fiber. By designing a multi-layer cladding with a high hydrogen content as a neutron moderation material, the moderation effect of neutrons is significantly improved. At the same time, the boron element and rare earth elements with a large neutron absorption cross section doped in the multi-layer cladding are controlled, which can absorb thermal neutrons and do not release rays, thereby achieving the effect of anti-neutron radiation.

A core of a fast nuclear reactor has at least one gas expansion module, at least one neutron absorber, and at least one neutron moderator. The gas expansion module has a hollow tubular structure with one end closed and the other end opened. The at least one neutron absorber adjoins an outer face, in a radial direction of the core, of each gas expansion module. The at least one neutron moderator adjoins an outer face, in a radial direction of the core, of each gas expansion module. The at least one neutron absorber also adjoins the at least one neutron moderator.

An electromagnetic pump (EMP) for a liquid metal-cooled nuclear reactor includes a pump casing, concentric inner and outer flow ducts collectively defining a flow annulus extending coaxially with a longitudinal axis of the EMP, and induction coils configured to control the flow of liquid metal coolant through the flow annulus based on electrical power received from the power supply. At least one of the inner flow duct or the outer flow duct includes a gamma shielding material configured to block gamma rays from entering an interior of the EMP from the flow annulus. The pump casing may include a neutron absorber material configured to absorb neutrons entering the pump casing from an exterior of the EMP. The EMP may include a neutron moderator material on an outer surface of the pump casing and configured to moderate neutrons entering the pump casing to be absorbed by the neutron absorber material.

The invention relates to the technical field of radiation experiments, and discloses an animal experiment anti-radiation protection device which comprises a base and a neutron moderation plate fixed on the base, and further comprises a neutron reflection plate arranged on the base in a sliding manner, and a neutron absorption plate is embedded in one surface of the neutron moderation plate and is octagonal; the self-hooping part is arranged in the mouse sleeve; the protecting part is arranged on the mouse sleeve and is connected with the self-hooping part; the cleaning and spraying part is arranged in the mouse sleeve and is connected with the protecting part; the dose of thermal neutrons is optimized through the neutron moderation plate, the upper sleeve and the lower sleeve are matched to ensure that only tumors are exposed to a thermal neutron area, irradiation damage to other parts of a mouse is reduced, push-pull of the upper sleeve drives the L plate to move along the guide groove, the T sleeve rotates in a matched mode, the strap is controlled to be tightened or loosened, and during tightening, the strap and the lower sleeve form a constraint space to fix the mouse; when the mouse is relaxed, the rubber band elastic auxiliary hoop rebounds, the mouse is released, manual binding is not needed, and the operation process is simplified.

The invention belongs to the technical field of boron neutron capture therapy of tumors, and relates to interventional boron neutron capture therapy equipment. The interventional boron neutron capture therapy equipment comprises a neutron generator, a neutron moderator and a neutron export injector, the neutron generator is used for bombarding a target material by using an incident high-energy particle beam to generate neutrons; the neutron moderator is connected to the neutron generator and used for moderating neutrons generated by the neutron generator into thermal neutrons and shielding gamma rays generated in the moderating process; and the neutron export injector is connected to the neutron moderator and is used for guiding and transporting the moderated thermal neutrons to a treatment part in the body of a patient. Therefore, the problem that a BNCT neutron transport scheme in the prior art cannot effectively consider the neutron utilization rate, the treatment depth and extra radiation damage borne by a patient can be solved.

This invention provides a yttrium hydride material with a hydrogen permeation barrier coating and a method for preparing the hydrogen permeation barrier coating. The method includes the following steps: adding aluminum salt and chromium salt to a mixed solvent containing alcohol, reacting with stirring, and aging to prepare an alumina and chromium oxide composite sol-gel system; immersing a cleaned yttrium hydride substrate into the alumina and chromium oxide composite sol-gel system, and forming a composite sol-gel film on the surface of the yttrium hydride substrate using an dip-coating method; and calcining the yttrium hydride substrate containing the composite sol-gel film to transform the composite sol-gel film into a dense hydrogen permeation barrier coating. This invention prepares the raw materials constituting the coating into a sol system, and uses an dip-coating + calcination method to form a hydrogen permeation barrier coating on the surface of the yttrium hydride substrate. The yttrium hydride material with the hydrogen permeation barrier coating can be used in small nuclear reactors as a neutron moderator, which can effectively improve the service life of the yttrium hydride material.

This invention relates to the field of radiation experiment technology and discloses an animal experiment radiation protection device, including a base and a neutron moderator plate fixed on the base. It further includes: a neutron reflector plate slidably disposed on the base, with an octagonal neutron absorber plate embedded on one side of the moderator plate; a self-closing part disposed inside a mouse sleeve; a removal part disposed on the mouse sleeve and connected to the self-closing part; and a cleaning spray part disposed inside the mouse sleeve and connected to the removal part. This invention optimizes the thermal neutron dose through the neutron moderator plate, and, in conjunction with the upper and lower sleeves, ensures that only the tumor is exposed to the thermal neutron region, reducing radiation damage to other parts of the mouse. The push-pull mechanism of the upper sleeve drives the L-plate to move along the guide groove, and the T-tube rotates accordingly, controlling the tightening or loosening of the closing strap. When tightened, the closing strap and the lower sleeve form a restraint space to fix the mouse; when loosened, the elastic band assists the closing strap to rebound and release the mouse, eliminating the need for manual binding and simplifying the operation process.

The invention discloses a neutron scattering experiment simulation method, device, equipment and product. The method comprises the following steps: constructing a scattering front-end model of a target scattering spectrometer; wherein the scattering front-end model comprises a neutron moderator and a slit; simulating the movement process of neutrons with different incident energies from the neutron moderator to the slit, and extracting neutron beam data in the movement process; constructing a sample environment model and a detector array model of the target scattering spectrometer; wherein a sample is arranged in the sample environment model; and performing a scattering experiment based on the neutron beam data of the selected incident energy, the sample environment model and the sample, intercepting neutrons after the scattering experiment by using the detector array model, and generating a scattering simulation result of the neutrons. The virtual scattering experiment method for the high-energy inelastic neutron scattering spectrometer is developed, so that the optimal setting of part of experiments can be cleared in a relatively low-time-cost manner before the real experiment is carried out, and the situation that the supply of the current spectrometer experiment machine is tense is relieved.

The application relates to a high-temperature-resistant composite neutron moderator material and a manufacturing method thereof, and belongs to the nuclear power field. The manufacturing method of the high-temperature-resistant composite neutron moderator material comprises the following steps: determining the hydrogen partial pressure of a metal hydride at a working temperature, establishing a moderator material particle model comprising a metal hydride core, a buffer layer and a SiC sealing layer and calculating the stress borne by the SiC sealing layer at the working temperature; calculating the allowable stress of the SiC sealing layer at the working temperature and adjusting the moderator material particle model according to the allowable stress to obtain a corrected moderator material particle model; and manufacturing a high-temperature-resistant composite neutron moderator material finished product based on the corrected moderator material particle model. The method can be used for manufacturing a neutron moderator material with good stability and reliability at a high temperature, and improves the safety and reliability of a commercial nuclear power plant reactor.

A radioisotope production capsule is described. Each capsule includes generally an inner container for housing one of a target material and a neutron moderator, an outer container surrounding the inner container for housing the one of the target material and the neutron moderator not housed by the inner container, and cladding for isolating the target material from the neutron moderator. One or more modular capsules are placed in each of a plurality of plug fingers. Each single plug finger loaded with one or more capsules is inserted into a guide thimble of an array of guide thimbles in a fuel assembly.

The invention discloses a neutron moderator, a neutron moderator, a preparation method and application, and belongs to the technical field of neutron moderation. The neutron moderator comprises a cage-shaped hydrate formed by water and hydrogen-containing gas, and the cage-shaped hydrate contains isotope deuterium of hydrogen. The neutron moderator contains a large number of H atoms and D atoms, and the neutron moderation efficiency can be improved. Moreover, the hydrogen-containing gas in the cage-shaped hydrate is bound in the cage-shaped frame, and the neutron absorption cross section of bound-state hydrogen is reduced, so that the neutron flux can be improved, and the loss of the number of neutrons is reduced.

The present invention discloses a push-type controllable source neutron porosity measuring device, which relates to the technical field of oil and gas development. It includes a housing and push arms installed outside the housing. Inside the housing, there are a deuterium-tritium neutron tube, a neutron moderator, a neutron detector, a neutron shield, and a neutron absorber. The neutron moderator is used to reduce the energy of the fast neutrons emitted by the deuterium-tritium neutron tube. The neutron shield is used to shield the neutrons directly emitted by the deuterium-tritium neutron tube to the neutron detector. The neutron absorber is used to absorb and shield the thermal neutrons from the wellbore direction. The push-type controllable source neutron porosity measuring device provided by the present invention significantly improves the porosity sensitivity of the deuterium-tritium source neutron porosity logging tool in open-hole wells by using a small-diameter deuterium-tritium neutron tube, a neutron moderator, a neutron absorber, and a measurement method close to the wellbore wall, realizes the application of the deuterium-tritium source on the open-hole well neutron porosity instrument, and ensures the personal safety of the instrument operators.

A nuclear fission reactor comprising a passive thermal shut-down device, and a reactor core containing fissile fuel. The passive thermal shutdown device comprises a reservoir and a Pythagorean syphon. The reservoir is in thermal communication with the reactor core, and containing a neutron poison material which has a free surface. The Pythagorean syphon has an inlet within the reservoir, an outlet in fluid communication with the reactor core. When the neutron poison material overtops the syphon due to thermal expansion, the neutron poison material flows through the Pythagorean syphon and into the reactor core. Also provided are nuclear fission reactors having passive thermal shutdown devices using a Pythagorean syphon to control the flow of fissile fuel, neutron moderators, or neutron reflectors.