8 results about "Radioactive Disintegrations" patented technology

The application provides a method and system for evaluating the whole range of radiation risk outside a nuclear power plant in a severe accident, and the method comprises the following steps: S1, a basic model architecture for evaluating the risk of radioactive accidents is built, the model requirements are adapted, and a corresponding basic database is established; S2, the characteristics of the radioactive plume after the accident are constructed; S3, the spatial gridding of the accident site and the discretization of the plume transmission are calculated; S4, the sampling meteorological conditions are obtained, and the plume transmission is simulated; S5, the radiation dose in the early stage of the grid domain is calculated, and the risk is evaluated; S6, the health effects in the early stage of the grid domain are evaluated; S7, the radiation dose in the medium and long term stage of the grid domain is calculated, and the dose risk is evaluated; S8, the health effect risk in the medium and long term stage is evaluated, and the consequences of the accident in the medium and long term stage are evaluated. The application simulates the whole transport process of the radioactive plume in a severe accident, considers the dry and wet deposition of the plume and the loss effects such as radioactive decay, and determines the activity of the radionuclide deposited on the ground and retained in the air within the spatial range outside the scene.

The application provides a method for evaluating radioactivity in a limited space based on a plume diffusion mode, which is mainly used for evaluating radioactivity concentration distribution in the limited space, and the method comprises the following steps: equivalent processing of a radioactivity diffusion process, regarding the radioactivity diffusion process as a plume bundle composed of a plurality of smoke clusters, and obtaining the radioactivity concentration distribution through a Gaussian smoke cluster diffusion model; improving a traditional Gaussian smoke cluster model by considering radioactivity source intensity variation, gravity settlement and environmental wind speed, considering the variation of the radioactivity intensity of the smoke cluster according to radioactivity decay, considering the offset amount of the gravity settlement to the center line of the plume according to Stokes formula, and synthesizing and superimposing diffusion speed according to the parallelogram rule to combine the environmental wind speed and the radioactivity self-diffusion speed; and superimposing the radioactivity concentrations of all the smoke clusters according to the improved smoke cluster model to evaluate the radioactivity concentration in the limited space.

The invention discloses a time-space sequence modularization supergravity test method for simulating a nuclide ten-thousand-year migration process in a geological barrier and application of the time-space sequence modularization supergravity test method. A kilometer-level geological barrier is spatially dispersed into representative space-time sequence geological modules such as a deep part-near part, a middle part, a shallow part-far part and the like along a nuclide migration path so as to realize reconstruction of a ten-thousand-year full-cycle migration process. A differentiated entity fracture model is constructed through 3D printing for different modules, and differentiated stress and hydraulic boundary conditions matched with the geological depth are applied under a high gravity field. The test adopts stable replacement nuclide, and through a concentration correction method based on transmission lag and a radioactive decay law, outlet concentration data of an upper-level module is converted into an inlet concentration boundary of a lower-level module, so that continuous tests of different space-time sequence geological modules are realized. And finally, restoring a time scale and splicing data by using a supergravity physical simulation similarity law, and reconstructing a full-path concentration penetration curve of the nuclide under a ten-thousand-year scale.

The present application relates to the field of radon Rn222 measurement, and particularly to a radon measuring instrument calibration radon Rn222 measuring chamber and a testing method thereof. The radon measuring instrument calibration radon Rn222 measuring chamber comprises a sealed chamber, a radium chloride 226 decay chamber arranged in the sealed measuring chamber and provided with a decay chamber to release radon Rn222 by radioactive decay of radium chloride 226, an air inlet hole and an air outlet hole arranged at two ends of the radium chloride 226 decay chamber respectively, a radon measuring instrument assembly arranged at one end of the radium chloride 226 decay chamber and connected with the air outlet hole, the radon measuring instrument assembly being provided with a plurality of radon measuring instruments to measure radon Rn222 released by radioactive decay of radium chloride 226, and an air inlet assembly. The present application realizes functional integration through modular design, solves the problems of dispersed structure and complex operation of traditional calibration equipment, breaks through the bottleneck of single-channel efficiency through parallel measurement of multiple radon measuring instruments, meets the batch calibration demand, and guarantees stable radon concentration through linkage of the air inlet assembly and the decay chamber, thereby laying a foundation for high-precision calibration.

A low-temperature seed-induced growth method for salicylamide ultrafast scintillation crystals is disclosed, involving ultrafast scintillation crystals and their low-temperature seed-induced growth method. This method aims to solve the technical problems of uncontrollable growth rate, sensitivity to environmental fluctuations, easy generation of microscopic defects within the crystal, and poor dimensional regularity in existing organic crystal scintillators. The method comprises: 1. Obtaining high-quality seed crystals through isothermal volatilization; 2. Preparing a saturated growth solution; 3. Precise temperature equilibration treatment; 4. Seed crystal-induced slow volatilization growth. The salicylamide single crystals prepared by this method reach a size of 15mm × 9mm × 1.5mm. Its photo-induced decay time is approximately 5.93 ns. 137 The radioactive decay time under Cs excitation is approximately 2.82 ns, which can be used in the field of radiation detection.

The invention relates to a process for producing medical-grade lead-212, comprising the steps of: a) production of lead-212 by radioactive decay of radium-224 in at least one first chromatography column containing a first stationary phase on which radium-224 is fixed; b) elution of the lead-212 thus produced from the first stationary phase; c) loading of the eluate thus obtained into a second chromatography column containing a second stationary phase to fix the lead-212 on the second stationary phase; d) washing of the second stationary phase; d) elution of the lead-212 from the second stationary phase; and characterized in that: - step b) comprises circulating in said at least one first chromatography column an ​​aqueous solution A1 comprising from 0.8 mol / L to 1.6 mol / L of a chloride, optionally with at most 200 mmol / L of HCl;and- step d) includes circulating an aqueous solution A2 comprising 0.01 mol / L to 1 mol / L of chloride through the second chromatography column. Applications: manufacture of lead-212 based radiopharmaceuticals, useful in nuclear medicine.

The invention discloses an ecological environment pollution risk assessment method and system, and the method comprises the following steps: collecting radioactivity monitoring data of a target region, and carrying out the preprocessing; constructing a radioactive pollution space-time distribution observation field of the target area, and generating a pollution observation field matrix; coupling the nuclide decay process and the diffusion migration process to form a radioactive decay-diffusion coupling evolution model; constructing a pollution digital twinborn evolution field, and performing simulation calculation on the pollution diffusion state of the target area under the continuous time sequence; constructing a pollution source hypothesis set, and forming a pollution source parameter vector set; iteratively updating and optimizing the pollution source parameter vector set; and calculating a radioactive risk value of each space unit of the target area, performing risk grade division, and generating an ecological environment pollution risk assessment result. According to the method, the radioactive contamination risk assessment is realized by using the decay diffusion coupling and digital twinborn inversion methods, and the method has the advantages of high accuracy and strong space-time description.

The invention belongs to the field of isotope geological theory application, and particularly relates to a correction method for the 238U / 235U ratio of a U-Pb isotope system and application of the correction method. The method comprises the steps that 238U and 235U atomic number calculation formulas are arranged according to the radioactive decay law; according to an atomic number calculation formula of 238U and 235U, calculating the initial abundance Ni of parent isotopes 238U and 235U at different moments and the ratio of 238U / 235U, and analyzing the relative deviation of the ratio of 238U / 235U relative to 137.88; a 238U / 235U equation is established for the middle stage of the U-Pb three stages, and evaluation is carried out; and comparing a 238U / 235U calculated value with 207Pb age errors calculated by an original parameter 137.88, and determining qualitative and quantitative use ranges and conditions. According to the method, the reliability of age calculation can be effectively improved, and the method is applied to U-Pb isotope age calculation and isotope evolution research.