32 results about "Fission neutron" patented technology

The present invention includes an apparatus and method for neutron radiation detection. The apparatus comprises combining thin walled, boron-coated straw tubes with a plastic moderator material interspersed around the tubes. The method involves using such an apparatus through application of voltage to a central wire running inside the tubes and collecting electrical pulses generated thereby.

The invention discloses a nuclear reactor core capable of improving neutron flux rate; the core is a circular structure; the center of the core is a Be thermal neutron well region, the circumference of which is a fuel component region, the circumference of which is a Be reflecting layer; the whole core is a circular structure. The maximum thermal neutron flux rate of the central Be thermal neutron well region can be over twice larger than that of the fuel region ; as the thermal neutron well region can be provided with fuel component with high uranium content, the fuel component center can form fast neutron region, therefore, the generated fission neutron has high flux rate.

The invention relates to a method for calibrating and correcting a fission neutron logging instrument. The neutron count rate by the well wall and along the well axis after water correction; 4. Obtain the neutron count rate by the well wall and along the well axis after the epithermal neutron life correction in the measured well; the present invention can directly measure the uranium content, and Compared with the chemical analysis results of hole core sampling, the deviation does not exceed 10%; the present invention reflects the grade of uranium ore more objectively, especially in the section where the balance of uranium and radium is destroyed, combined with conventional gamma logging, the drilling section can be determined on site The uranium-radium balance coefficient reduces the number of core samples and reduces the cost of uranium resource exploration; the invention can accurately measure the uranium leaching rate in in-situ leaching mining, and avoid environmental pollution and Waste of cost has important practical significance for improving the efficiency of in-situ leaching mining and smelting, reducing costs and protecting the environment.

The invention discloses a dynamic demonstration instrument for nuclear fission chain reaction, which comprises a bracket, a glass container, a baseplate, a ball inlet, a rocking cylinder, an air pump, a blowing mouth, a programmable controller, a fission neutron ball and an incident neutron ball. The glass container is arranged on the bracket; the baseplate is arranged under the glass container; a together-aligned atomic nucleus model is arranged on the baseplate; a recession is positioned on the baseplate, which is corresponding to the atomic nucleus model; the fission neutron ball is arranged inside the recession; the blowing mouth is arranged at the lower part at the lateral side of the glass container; the shaft of the rocking cylinder bears one side of the baseplate at the bottom of the baseplate; the ball inlet is situated upon the glass container; and the rocking cylinder is connected with the programmable controller. The demonstration instrument of the invention dynamically demonstrates the nuclear fission chain reaction, thus facilitating the popularization of science and education for the knowledge about nuclear fission.

A fission source extrapolation method for accelerating the Monte Carlo criticality calculation. By setting an initial fission source for the Monte Carlo criticality calculation, neutron transport simulation can be performed according to the initial fission source, and the spatial distribution of the fission source can be counted; Then, based on the setting that the fission source will gradually converge to the real solution, the fission source is linearly extrapolated. Finally, the entire calculation model is divided into multiple fission regions, and the source extrapolation factor is used to adjust the number of fission neutrons in each region. The invention can remarkably improve the convergence speed of the fission source of the Mongolian card calculation of the reactor, and can be used as an acceleration module of the Mongolian card program, so that it can be used by a variety of Mongolian card programs, and the efficiency of the critical calculation of the Mongolian card is significantly improved.

The present invention relates to a gas scintillation based fission neutron detector. The detector comprises a detector barrel, an entrance window hermetically arranged at the front end face of the detector barrel, an exit window hermetically arranged at the rear end face of the detector barrel, two quartz windows arranged at two lateral surfaces of the detector barrel, at least two target stands fixed in the detector barrel, fission targets suspended on the corresponding target stands, two photoelectric detectors arranged outside the two quartz windows respectively, a charging tool communicated with the detector barrel, and scintillation gas filled in a barrel core; and the scintillation gas adopts inert gas or nitrogen. The gas scintillation based fission neutron detector solves the technical problems of low neutron / gamma resolving power and low neutron sensitivity in the conventional neutron detector, and has the advantages of smooth fast neutron energy response and quick time response.

A method for solving neutron transport for reactors with uniform distribution of materials that combines machine learning and Monte Carlo methods. The first step is to construct a series of reactors with a uniform distribution of materials, each containing a different material composition or density. These reactors were then solved using the Monte Carlo method, and the neutron scattering and fission probabilities and the characteristic distribution of neutrons were calculated after the simulation. Using these probability and feature distribution data, a fully-connected neural network model is trained that takes neutron energy and material composition as input and the feature distribution of scattered and fission neutrons as output. Finally, using the obtained fully connected neural network model, the neutrons and materials produced by fission are used as inputs to obtain the next generation of fission neutrons, and the calculation is iterative until convergence. Compared with the existing Monte Carlo method, the method no longer needs to perform a large number of sampling processes, and the calculation speed is faster, and the neutron transport calculation can be quickly completed for a reactor with uniform distribution of materials.

The invention discloses a fuel assembly available for integral replacement. By fixation of the fuel assembly and a top cover, axial fixation of the fuel assembly is realized, a fuel assembly fixation problem caused by a high-density cooling agent of a liquid-state lead-based reactor is solved, and integral replacement of the fuel assembly is realized. Since fuel elements with fixed upper ends and free lower ends are reinforced under the action of axial flushing force and buoyancy of the cooling agent, stability of the fuel elements in operation of the reactor is improved; owing to a moderator filled in each fixed rod, fission neutron moderation can be accelerated to improve reactivity of a reactor core and reduce the size of the reactor core. The fuel assembly has advantages of high safety, simple structure, small reactor core size and the like.

Methods and systems that utilize centrifugally tensioned metastable fluid detector (CTMFD) sensors and an external probing source to detect the presence of fissile and fissionable materials, including but not limited to special nuclear materials (SNMs), in containers. Such a method includes subjecting a container to probing with a fission-inducing radiation species that induces fission in an fissile or fissionable material, detecting fission neutrons emitted from the fissile or fissionable material with CTMFD sensors that each contain a detection fluid in which the fission neutrons induce cavitation in a centrifugally tensioned portion of the detection fluid. A threshold energy neutron analysis mode is then utilized to reject the radiation species and detect a fraction of the fission neutrons that have energies above a predetermined energy threshold determined by centrifugally-induced tension in the centrifugally tensioned portion of the detection fluid within each of the CTMFD sensors.

The invention discloses a uranium fission prompt neutron logging technology based on the ratio of epithermal neutrons to thermal neutrons. Specifically, it means that fast neutrons, also known as primary neutrons, are emitted to formation rocks in a pulsed manner in a borehole. Primary neutrons are successively moderated into epithermal neutrons and thermal neutrons by the medium in the well. Thermal neutrons induce 235U fission and emit uranium fission prompt neutrons, also known as secondary neutrons. The secondary neutrons are successively moderated into epithermal neutrons and thermal neutrons, and induce 235U fission again. At any time t after the primary neutrons are moderated into thermal neutrons, the total amount of epithermal neutrons nE(t) in the formation rock is proportional to the total amount of existing thermal neutrons nT(t) and the uranium content qu, that is, nE(t)∝nT(t)·qu. Using the dual neutron detector and dual time spectrometer disclosed in the invention, the time spectrum of epithermal neutrons and thermal neutrons is measured, and the epithermal neutrons from the time when primary neutrons are slowed down to thermal neutrons to any time are defined , The ratio of thermal neutron attenuation is the "E / T" ratio, and a real-time uranium quantification algorithm based on saturated ore bed is constructed.