[en] The paper analyzes the factors affecting the safety of nuclear and radiation environment. The nuclear and radiation environment safety evaluation index system is established. Combining with the computer technology of ASP.NET, SQL Server and modern management information system technology, the nuclear and radiation environment safety management ar and evaluation system is designed, and the reliability and stability of the system are verified through examples. The system can manage the information affecting the safety of nuclear facilities and radiation environment, analyze to provide early warning for geographical monitoring data, and comprehensively evaluate the single index and the overall safety, so as to provide technical support to units operating nuclear facilities for their safety early warning and management decision-making. (authors)

[en] In present paper, the method of processing the singular points of γ energy spectrum was established by using Lipschitz exponent and wavelet transform. The principle of modulus maximum denoising and the alternating projection reconstruction algorithm proposed by Mallat were analyzed, and the processing model of γ ray energy spectrum data was established. The wavelet transform modulus maximum denoising software was designed based on MATLAB, and the method was simulated and analyzed with the actual-measurement γ ray energy spectrum data. The results show that the method using wavelet transform and alternating projection is good at noise reduction and reconstructing the energy spectrum data. (authors)

[en] Chemical explosion accidents of uranium materials produce radioactive aerosol endangering human health. It discusses the formation and hazard of uranium aerosol. According to the different wind speed, meteorological factors and geographic conditions, the Hotspot nuclear accident aftereffect evaluation model was used to calculate radiation characters, which comparison and analysis conform to the record of the relevant documents The computational results show that different wind speed, meteorological factors and geographic conditions correspond to different features of radiation and some rules, which has obvious effect on radiant hazard and disposal. (authors)

[en] Based on the factors that affect the safety of nuclear and radiation environment, this paper establishes the evaluation index system of nuclear and radiation environmental safety. And designs the nuclear and radiation environmental safety assessment using computer technology such as ASP. NET and SQL Server database and nuclear and radiation environmental safety evaluation index system And the information management system, and through the example to verify the system reliability and stability. The system is designed with three-tier architecture, which is divided into resource layer, core business application layer and user layer from bottom to top. It can realize three functions: one is to classify and manage the information of nuclear and radiation environment. The second is the combination of geographic information technology on the geographical monitoring data for real-time analysis of the warning. Third, the system can achieve a single measure of nuclear facilities and overall safety evaluation. The development of the system can provide technical support for nuclear facilities and facilities for nuclear and radiation environmental safety warning and management decision-making. (authors)

[en] Based on the CFD theory, a discrete phase model (DPM) was developed using FLUENT for digital simulation. By comparing different explosive load factor β and ventilation system, the motion law and concentration of PM₁₀ particles were analyzed. Finally, this paper studied the effect of ventilation system on particle dispersion and provided a theoretical reference to the radiological protection and emergency response to dirty bomb incidence. (authors)

[en] In order to accurately estimate and evaluate the annual effective dose of basement personnel, a simulation model of basement radon concentration distribution based on fluent platform was established. Combined with RAD7 experimental measurement data, the influence of ventilation rate and opening and closing state on the concentration distribution of basement radon was systematically discussed. The results show that the simulation results agree well with the experimental results, indicating that the simulation method based on CFD technology can be used to study the distribution of radon concentration. Under the condition of no ventilation, the radon concentration is generally uniformly distributed in the ventilation conditions. Under the sputum concentration, the sputum concentration can be reduced to the outdoor level. The dose conversion formula is used to calculate that the dose received by the personnel is about 1/10 of that without ventilation. The research method can provide a scientific basis for the monitoring, evaluation and corresponding protection work of cockroaches. (authors)

[en] In order to predict the environmental pollution of traditional BP neural network, there are some shortcomings such as large prediction error, weak generalization ability and slow convergence speed. It is proposed to replace the traditional BP neural network mean square error criterion with the principle of maximum entropy and derive the neural network connection right under the principle of maximum entropy. The value and threshold adjustment formula establishes the maximum entropy BP neural network. Finally, the simulation experiment of Radon concentration monitoring data is carried out on MATLAB platform. The results show that the average prediction error of the improved model is 5.22%, which is lower than the traditional BP neural network, and has the advantages of reliable prediction results and strong generalization ability, and is used for environmental enthalpy concentration prediction studies. (authors)

[en] The process and mechanism of cloud diffusion in nuclear material chemical explosion accidents were analyzed in this paper to obtain the parameters of the cloud and the aerosol diffusion law. A numerical simulation method for cloud diffusion based on CFD technology was established. The simulation method was verified by conducting an external field diffusion experiment of the explosion cloud. The results show that the simulation of cloud diffusion can be realized by CFD method. The experimental and simulated clouds show that the explosion height of small equivalent TNT is much smaller than that of Church's empirical formula, and the width ratio increases. The aerosol particles are unevenly distributed in the flow field of the mushroom double-vortex ring cloud. The particles with size greater than 50 μm are mostly located in the cloud column, while most of the respirable particles are concentrated at the top of the cloud. The aerosol source term parameters are changed by the dispersal and sedimentation before the cloud is stabilized. The calculation of the aerosol accumulation mass distribution in the Operation Roller Coaster experiment shows that the airborne release fraction is about 58% of the surface gasification rate, the respirable fraction increases from 20% to 31%, and the respirable release fraction is about 18%. (authors)