111 results about "Neutron energy spectrum" patented technology

A tube-style neutron detector, a panel-style neutron detector incorporating a plurality of tube-style neutron detectors, and a panel-style neutron detector including a plurality of anode wires are provided. A plurality of channels is provided in a neutron detector such that each channel has an inner surface of a coating layer including a neutron-absorbing material. A wire anode is provided at end of each channel so that electrons generated by a charged daughter particle generated by a neutron are collected to detect a neutron-matter interaction. Moderator units can be incorporated into a neutron detector to provide improved detection efficiencies and/or to determine neutron energy spectrum. Gas-based proportional response from the neutron detectors can be employed for special nuclear material (SNM) detection. This neutron detector can provide similar performance to ³He-based detectors without requiring ³He and without containing toxic, flammable, or high-pressure materials.

The invention belongs to the technical field of the nuclear reactor engineering, particularly to the water-cooling two-region multiplication nuclear reactor core and the nuclear reactor adopting the same, wherein the water-cooling two-region multiplication nuclear reactor core includes a fast neutron energy spectrum area adopting the coating grain sheath fuel assembly and a thermal neutron energy spectrum area adopting the dense rod bundle fuel assembly or the coating grain sheath fuel assembly. The water-cooling two-region multiplication nuclear reactor core of the invention adopts the coating grain sheath fuel assembly, which breaks through the restrain of the stainless steel shell to the outlet scream temperature, realizes the higher coolant outlet temperature, meanwhile the fast neutron core is leaked to the thermal neutron energy spectrum core constituted by the rod bundle fuel assembly dense boom at the subcritical to be multiplied.

Disclosed is a method for acquiring nuclear fuel assembly resonance parameters. The method includes the following steps: building a commonly-used nuclide multi-group database and a changing curve of resonance peaks along with energy; distinguishing isolated peaks and dense peaks, wherein the interval where the isolated peaks are located is a resonance energy region low energy section with obvious resonance interference, and the interval where the dense peaks are located is a resonance energy region high energy section without obvious resonance interference; solving a subgroup total cross section, a subgroup partial cross section, subgroup probability and corresponding multi-group data coupling in the resonance energy region high energy section by using a subgroup method; coupling calculation of the resonance energy region high energy section and calculation of the resonance energy region low energy section through inter-group scattering from the high energy section to the low energy section, acquiring the resonance parameters of the high energy section, and then calculating a scattering source and a fission source from the high energy section to the low energy section; acquiring a multi-group neutron energy spectrum in a low energy region by using a wavelet expansion method; and merging and continuing the total cross section and the partial cross section by using the multi-group neutron energy spectrum of the resonance region low energy section to acquire the nuclear fuel resonance parameters of the low energy section. By means of the method, resonance parameters of nuclear fuel assemblies with any resonance material composition, any geometry and any quantity of resonance regions can be effectively acquired.

The invention discloses a spherical multilayer polyethylene moderation body, which is formed by accumulating a plurality of spherical polyethylene moderation bodies with different inner diameters layer by layer from inside to outside, wherein the inner diameter of the first spherical polyethylene moderation body is equal to the diameter of a spherical neutron detector 1, and the inner diameter of ith spherical multilayer polyethylene moderation body is equal to the outer diameter of the (i-1)th ball, wherein i is equal to 2, 3, 4 and so on. A neutron energy spectrum and fluence measurement device of a single probe comprises the spherical multilayer polyethylene moderation body, the spherical neutron detectors, a nuclear electronics circuit, a high and low voltage circuit, and a single chip. The spherical polyethylene moderation body can moderate the neutron, so that the neutron after being moderated can be detected by the neutron detectors. The nuclear electronics circuit can amplify the signals detected by the spherical neutron detectors and can implement n-Gamma screening. The single chip can process the signals and can display final result. The spherical multilayer polyethylene moderation body has the advantage of good consistency. The neutron energy spectrum and fluence information can be obtained by using the device disclosed by the invention.

The invention discloses a device and a method for [gamma] and neutron double ray power spectrum measurement. The [gamma]-ray signal and the neutron signal are distinguished by particle discrimination by using the feature of a scintillation crystal being sensitive to the [gamma]-ray and the neutron at the same time. The pulse amplitudes of the two signals are analyzed respectively to obtain the [gamma]-ray deposition spectrum and the neutron deposition spectrum. The [gamma]-ray has a peak response in the scintillation crystal, and the [gamma]-ray spectrum is the measured [gamma]-ray power spectrum. The neutron is continuously responsive in the scintillation crystal. The neutron power spectrum is solved by the least squares of the response matrix and the neutron deposition spectrum of a single energy neutron. Finally, by analyzing the energy spectrum data, the key nuclide is identified and the content thereof is calculated, and the [gamma] dose and the neutron dose are calculated. The portability of the instrument for mixed radiation field measurement is effectively improved and the mutual interference between the [gamma]-ray and the neutron is avoided.

A continuous neutron spectrum real-time detection system comprises a plurality of spherical-shell polyethylene moderation layers, a plurality of spherical-shell thermal-neutron detector systems, an electronics system, a computer system, an input power supply interface, a signal output interface, a display panel and a switch; and after neutrons with different energies enter the detection system, the neutrons are moderated by different moderation layers to thermal neutrons to be finally detected by the detector system of one layer, a pulse signal is transmitted to the electronics system, the electronics system analyzes and outputs relevant signals according to signals inputted by different detection layers, finally the computer system outputs a corresponding energy value according to different signals outputted by the electronics system and draws and records an energy spectrum. The continuous neutron spectrum real-time detection system is small in size and capable of precisely measuring neutron energy spectrum on one position.

A neutron spectrometer that is more accurate, faster, and more-portable than conventional spectrometers includes an organic scintillator responsive to neutrons and gammas and an inorganic scintillator that captures neutrons. A processor receives signals representative of scintillations in the organic scintillator and in the inorganic scintillator and discriminates neutron signals from gamma signals. The processor also determines pulse areas for neutron moderating signals and performs unfolding based on the determined pulse areas to produce a neutron energy spectrum and/or dose information.

The invention provides an initial-spectrum-independent method for determining neutron energy spectrum in a reactor steady-state neutron field, and discloses a global optimization method for determining neutron energy spectrum by proposing an entropy function for representing neutron energy spectrum distribution and applying a corresponding maximal entropy principle. The initial-spectrum-independent method comprises the following steps of determining a neutron group structure, measuring and recording mononuclear activity of each nuclide, calculating and recording a microscopic cross section of each group of each nuclide, establishing a discrete activation equation set, establishing a probability distributing table of the neutron energy spectrum, and the like. According to the initial-spectrum-independent method disclosed by the invention, the problem that an existing method is dependent on initial spectrum and low in calculating efficiency is solved.

The invention discloses a metallic fast reactor fuel element irradiation test device. The device can be used for carrying out neutron irradiation test on metallic fast reactor fuel in a thermal spectrum research reactor and has the functions of neutron spectrum hardening, metallic fuel irradiation temperature control, fuel element heat release power measurement and the like. The device comprises aprotection tube, a cadmium tube, an irradiation test piece, a related gas pipeline, a thermocouple and the like. According to the device, a cadmium metal layer is adopted to absorb thermal neutrons to reduce the thermal neutron flux rate in the device, so that the neutron energy spectrum of a test fuel element is close to that of a fast neutron reactor; and the temperature difference is established between air gaps and a liquid metal layer outside a fuel rod, and the gas components in the air gaps in each irradiation part are independently adjusted, so that the temperature of fuel core bodiesin different irradiation parts are controlled within a required temperature range.

The invention discloses a neutron dynamical weighted Monte Carlo calculation method for continuous energy, and relates to a continuous energy weighted Monte Carlo dynamical method. According to the method, a time dimensionality and an energy dimensionality are imported in the particle simulation process so as to really simulate random walk processes, on space and time, of neutrons; when neutron collisions are processed, a concept of weights is imported to simplify the conditions after nuclear reaction of neutrons; in order to obtain a correct physical quantity or neutron dynamical parameter ona certain time and then obtain exquisite change of the physical quantity of neutron dynamical parameter along with the time, distribution, on energy, of neutrons, namely, a neutron energy spectrum, is detailedly considered and the neutron energy spectrum is convoluted with other parameters; and the applicability, precision and calculation efficiency of a Monte Carlo method in neutron dynamical calculation can be improved, physical quantities, such as neutron dynamical parameters and power, and exquisitely changing along with the time can be obtained by utilizing the Monte Carlo method, so that convenience is brought to analyze the physical processes and mathematical models.

The invention discloses a scintillator array structure, and a neutron detector employing the same. The structure comprises a plurality of scintillator layers, and the plurality of scintillator layers are stacked together to form the structure. The plurality of scintillator layers at least comprise two scintillator layers with different thicknesses. The scintillator array is formed by the stacking of the plurality of scintillator layers, and the structure is provided with scintillator layers with different thicknesses. Therefore, the structure can be suitable for the detection of different neutron energy spectrums, and effectively enlarges the detection range of the neutron energy spectrums.

The invention relates to fusion reactor tritium generating cladding neutron measuring. Helium cooling solid breeding agent tritium generating cladding neutron flux and spectrometry measuring system includes packaging foil pneumatic transmitting activation analysis subsystem which includes activation foil and pneumatic transmitting device. The activation foil is set in the measuring tube connected with operating station through cooling layer and biological shielding layer. The operating station is set helium cooling circuit and connected with helium gas dynamic force union station and HPGe measuring station connected with electronics and data gaining system. The solid breeding agent tritium generating cladding is also set micro-fission chamber combination detector and natural diamond neutron energy spectrum detector which are connected with operating station through current sensitive preamplifier and charge sensitive preamplifier, which is connected with electronics and data gaining system.

The invention discloses a control rod assembly comprising an axial partition control rod and a heavy metal absorber rod, belonging to the field of nuclear reactors. The control rod assembly is used for controlling the reactivity of a heavy metal cooling reactor; as a part of the control rod assembly, the control rod is inserted into a core part of the reactor together with a fuel assembly so as to control the reactivity. The control rod comprises a control rod assembly guide pipe (1), a coolant passage (2), a control rod housing (3), clearances (4), a moderator rod (5) and a heavy metal absorber rod (6). The control rod disclosed by the invention satisfies the reactivity control capability of the heavy metal cooling reactor and also overcomes the defects that a conventional control rod material has lower density than that of a coolant and has a weak neutron absorption capability under a fast neutron energy spectrum. The control rod assembly disclosed by the invention is simple in structure, reliable, and convenient to maintain.

The invention belongs to the technical field of petroleum and natural gas exploration, and relates to a density measurement method based on a D-D controllable neutron source. The controllable neutronsource and a multi-detector system are adopted, the gamma energy spectrums and the thermal neutron energy spectrums at different positions are recorded through pulse and measurement time sequence design, and the relation between the near-far capture gamma counting ratio, the near-far thermal neutron counting ratio and the stratum density under different stratum conditions is studied; then, a stratum density calculation model is theoretically determined through an existing spectral analysis and data processing method, the obtained density calculation value is compared with a reference value, and the precision is enabled to meet the measurement requirement; stratum density measurement is achieved through combination of a pulse neutron source and multiple detectors, thus a complete set of D-Dcontrollable source density measurement method is established, the method is of great significance to development of a new generation of pulse neutron-gamma density logging instrument and effective elimination of harm of tritium elements in the instrument to human bodies and the environment, and a guarantee is provided for safe exploration of unconventional stratums.

The invention relates to a measurement system for measuring a neutron flux in strong radiation and high temperature conditions and belongs to the technical field of nuclear reactor engineering. The measurement system mainly consists of a thermal neutron sensitive detector, a fast neutron sensitive detector, a thermal neutron absorber, two amplifiers, a data acquisition module and a neutron energy spectrum analysis module, wherein the thermal neutron absorber is wrapped around an outer surface of the fast neutron sensitive detector, signals detected by the thermal neutron sensitive detector and the fast neutron sensitive detector are respectively output to the two amplifiers, signals received by the amplifiers are processed and output, signals output by the amplifiers are subjected to digital processing operation via the data acquisition module, digitized signals are output by the data acquisition module, the neutron energy spectrum analysis module is used for subjecting received digitized signals to neutron energy spectrum analysis, neutron energy spectrum data can be obtained, and the neutron flux can be calculated based on the neutron energy spectrum data. The measurement system disclosed in the invention is advantaged by light weight, easy-to-install property, strong mobility, small measurement error and the like.

The invention relates to a multilayer spherical moderator container. A plurality of concentric hollow spherical shells having different inner diameters are combined with one another layer by layer from inside to outside so as to form the multi-layer spherical moderator container; the number i of the hollow spherical shells can be 1, 2, 3, 4, ..., and n; and if i is equal to 2, 3, 4, ..., n, a space between the i-th hollow spherical shell and the (i-1)-th hollow sphere spherical is communicated with an external liquid moderator loop through a pipeline corresponding to the space. The invention also provides a neutron energy spectrum real-time measuring device. The device includes a spherical neutron detector, a back-end nuclear electronic processing circuit, a multilayer spherical moderatorcontainer and a liquid moderator loop; the multilayer spherical moderator container wraps the spherical neutron detector; and the liquid moderator loop can control a liquid moderator in real time so as to make the liquid moderator fill or discharge from a space between an i-th hollow spherical shell and a (i-1)-th hollow sphere spherical shell provided that the number i of the hollow spherical shells is set to be 2, 3, 4, ..., and n, so that neutrons can be moderated, and can be easily detected by the spherical neutron detector. The neutron energy spectrum real-time measuring device of the invention can measure the energy spectrum of the neutrons in real time, and has the advantages of low cost and convenient use.

The invention provides a spectrum unfolding method for a neutron energy spectrum with integral weight. An activation foil weight factor is introduced into an iterative process, and a new truncation condition and a morbid data culling method are used. Neutron energy spectrum unfolding is accurately completed under a condition consistent with the physical reality. The method is based on statistical theory to deduce that the judgment truncation condition has a theoretical basis and is more in line with the physical reality compared with error truncation and truncation of iteration number of times of other methods.

The invention belongs to the nuclear radiation detection technical field and relates to a device for the real-time measurement of the energy spectrum of neutrons in a reactor. The device comprises a plurality of optical fiber probes, a plurality of optical fibers, a circuit module and a computer data processing system; each optical fiber probe comprises an optical fiber tail end and a detection material which coats the optical fiber tail end and is used for generating scintillation light; one end of each optical fiber is connected with each optical fiber probe, and the other end of the each optical fiber is connected with the circuit module, so that the optical fiber can be used for transmitting the scintillation light; the circuit module is used for converting and amplifying the signals of the scintillation light generated by the optical fiber probes into digital signals; and the computer data processing system is used for receiving the digital signal data from the circuit module, processing the digital signal data and rendering neutron spectra at positions where each optical fiber probe is located. With the device of the invention adopted, the signals can be acquired in real time, and neutron energy spectrum distribution at the positions where the optical fiber probes are arranged can be obtained, and therefore, and a defect that an existing activation sheet measurement technology requires a plurality of times of irradiation and spectrum unfolding and takes a long time to obtain energy spectra can be eliminated.

The invention discloses a matryoshk neutron spectrograph. The neutron spectrograph comprises a neutron radiation detection analysis processing device and a plurality of different-sized modulators; each modulator includes a container cup, a cup cover and water body; the container cup is a right circular cylinder; a handle disc is set at the center of the circular cup cover; connected through holesare set on the handle disc and the circular cup cover; a threaded hole connected with the through hole is set on the side wall of the handle disc; a fastener passes through the threaded hole to have aresisting connection with a hollow cylinder connection rod; the thickness of the wall of the container cup and the thickness of the circular cup cover are both 2 mm; the height of the handle disc is6 mm-15 mm; and, the minimum internal diameter difference between each two adjacent container cups of a plurality of container cups that are ordered from smallest to largest is 2 cm. The neutron spectrograph provided by the invention uses the water body as the modulator, is convenient to use and unlimited, satisfies the measuring capability of the neutron energy spectrum for the purpose of neutrondosimetry, effectively reduces the quantity and the space by pouring the water body in carrying or moving process, and provides a convenient and fast solution for the neutron energy spectrum field measurement.

The embodiment of the invention provides a neutron beam current device. The neutron beam current device is used for carrying out neutron energy spectrum adjustment on a neutron beam entering the neutron beam current device, wherein particles of the neutron beam comprise fast neutrons, epithermal neutrons, thermal neutrons and gamma photons. The neutron beam current device comprises a filtering part, an adjusting part and a collimator, wherein the filtering part is used for filtering fast neutrons in the neutron beam; the adjusting part is used for adjusting the neutron energy spectrum of the neutron beam so as to obtain an epithermal neutron beam or a thermal neutron beam; and the collimator is used for carrying out collimated emission on the adjusted neutron beam, wherein the filtering part, the adjusting part and the collimator are sequentially arranged in the neutron beam current device in a direction from a position that the neutron beam enters the neutron beam current device to aposition that the neutron beam is emitted out of the neutron beam current device. According to the neutron beam current device provided by the embodiment of the invention, two neutron beams, namely the thermal neutron or the epithermal neutron, can be provided through one beam current channel, so that two beam current channels do not need to be separately arranged, a larger space occupied by a plurality of beam current channels is avoided, and increase of construction cost is avoided.

The invention discloses a characterization method of a neutron-photon energy spectrum in a self-powered neutron detector. The characterization method comprises the following steps: 1, obtaining a sensitivity calculation model of the self-powered neutron detector; 2, obtaining a neutron energy spectrum and a photon energy spectrum near the self-powered neutron detector, and encrypting each energy group interval to obtain an encrypted neutron energy group and an encrypted photon energy group; 3, calculating the characteristic value of the fuel assembly again, obtaining a 573-group neutron energyspectrum and a 128-group photon energy spectrum near the self-powered neutron detector, and meanwhile checking the statistical variance of the neutron energy spectrum and the photon energy spectrum;4, obtaining neutron sensitivity and photon sensitivity of the self-powered neutron detector, and taking the neutron sensitivity and the photon sensitivity as reference values for energy group selection; and 5, respectively calculating photon energy spectrums corresponding to three types of common neutron energy groups and three types of photon energy group structures, calculating corresponding neutron sensitivity and photon sensitivity, comparing and analyzing reference values, and selecting an energy group structure with the minimum relative deviation with the neutron sensitivity and photonsensitivity reference values as an optimal neutron-photon energy group structure.

The invention provides a subcritical wrapping layer of transmutation of a pressure pipe type long-lived fission product. The subcritical wrapping layer of transmutation of the pressure pipe type long-lived fission product comprises a first wall, a transmutation area, a structural wall, a tritium breeding area and a shielding layer arranged from the outer side to the inner side in sequence. The transmutation area is cooled by high-pressure light water, and a pressure pipe type fuel assembly is adopted by the transmutation area. The transmutation area is cooled by high-pressure light water, and rich design and operation experience of a current nuclear power plant is effectively utilized. The light water has high moderating power, fissile nuclide of a fission wrapping layer in a thermal neutron energy spectrum has the high fission cross section, and energy magnification times of the wrapping layer are improved to a certain degree. Simultaneously, the pressure pipe type fuel assembly is adopted by the transmutation area, and the pressure of coolant is born by the pressure pipe type fuel assembly. The subcritical wrapping layer of transmutation of the pressure pipe type long-lived fission product is capable of effectively transmuting the long-lived fission product, and cost for design, and construction and operation of the wrapping layer is effectively reduced.