In order to better apply the electrokinetic in-situ leaching (EK-ISL) technology to the mining of low permeability uranium ore and improve the leaching efficiency of low permeability uranium ore, it is necessary to study it with numerical simulation technology. Starting from the physical and chemical behaviors in the process of in-situ leaching of uranium, the promotion of numerical simulation technology to in-situ leaching uranium were reviewed, the basic equations and solving methods of the model of in-situ leaching uranium were summarized, the key processes that need to be described by EK-ISL model were analyzed based on this, a preliminary numerical simulation model of electrokinetic in-situ leaching uranium was proposed.

The pumping and injection units in the well site of in-situ leaching production may have the situation that the injection volume is greater than the pumping volume, resulting in the diffusion of part of the leachate pollution beyond the leaching range. Through the target optimization method of the mining area, the single hole pumping and injection volume of the well site is optimized, and the pumping and injection volume of each pumping and injection unit in the mining area is effectively controlled to keep the total pumping volume greater than the total injection volume by 0.5%, so that the leaching solution is controlled within the well site as far as possible. According to the optimization results, the pumping and injection volume of each unit can be changed to realize the production and decommissioning of the mining area at the same time.

On the basis of meshing recovery area, design recovery stripes and recovery routes, forming the recovery strategy of starting from the cross section of flood shaft, advancing respectively upward and downward in wedge and wave shape, and at the same time put forward calculation formula of recovery capability of each route, and slope steady and draining measures during recovery process. The method is then verified by a specific engineering case, the results show that this method can eliminate interference of recovery machines, prominently boost recovery efficiency, and calculate precisely of recovery capability, which is good for recovery management.

In view of the shortage of important structural components, such as the liquid discharge device, upper head, resin buffer device, leachate inlet structure, liquid distribution device and resin buffer tank of the packed moving bed adsorption tower, the improved design of the structure was carried out by using the finite element method and the structural local adjustment method. The improved packed moving bed adsorption tower has been optimized in terms of functionality, use failure rate, replacement and maintenance frequency, simple and convenient operation and economy, the component structure is simple, the replacement of parts is convenient, reaching the expected goal.

The existing ore treating and leaching technology for low grade uranium-bearing molybdenum ore has the problems of low molybdenum leaching efficiency, high consumption of leaching reagents and high cost of industrial production. By the means of curing the ore with acid, the effects of particle size, acid content, acid curing ways, temperature and time on the curing effect and molybdenum leaching rate were studied mainly. The experimental results show that the molybdenum leaching rate of low grade uranium-bearing molybdenum ore can reach 72% after column leaching under the conditions of -3.2 mm size, 13% mass fraction of mixed acid, 4∶1 mL/g liquid-solid ratio, 85 ℃ curing temperature and 15 h curing time. The process has the advantages of short leaching cycle and low liquid-solid ratio, which is conducive to industrialization.

The relationship between the production cost and the lean uranium abundance of uranium enrichment plant was studied. By analyzing the influencing factors of uranium abundance on yield and cost under full-cost models, the relationship between cost and lean uranium abundance was calculated, and the best economic lean uranium abundance under different models was solved. The technical feasibility of reducing costs by adjusting the lean uranium abundance was analyzed, and suggestions for production adjustment of uranium enrichment plants were put forward. Through the research, the optimal lean material abundance under the full-cost mode was determined, which provides the reference for coordinating industry costs.

According to the production and management requirements of an in-situ leaching mine in Inner Mongolia, the general view diagram of the mining area and the operation diagram of the mining area were added to the host computer of the automation system, the remote parameter adjustment and alarm screen of the frequency converter were optimized, and the functions such as one key start and stop, one key given frequency were developed to realize the strict control of all links of in-situ leaching uranium production in the control and scheduling. Through the optimization of WinCC host computer, it can more intuitively display the equipment and production operation, further simplify the adjustment of instrument operation parameters, improve the working efficiency of operators and reduce production costs.

Taking the detection and control of centrifugal cascade in the first ⁷⁶Ge isotope separation project in China as the object, the hardware structure and configuration programming of DCS (Distributed Control System) were controlled to ensure the safety of the main process key equipment (the rotary stabilizer). The system realizes the real-time view of various process parameters on site, remote switches on and off the electric valve, starts and stops the vacuum pump, and adjusts the opening of the electric regulating valve on the process pipeline, which effectively ensures the safe and stable operation of the ⁷⁶Ge isotope production line.

The uranium tailings from a uranium mine in Hebei province were cured with cement and RD curing agent commonly used in the market. The mechanical properties and radon shielding properties of curing test blocks were studied, and the calculation formula for the optimal radon shielding layer was derived. The weathe rability test of the shielding layer was also carried out, and the microscopic mechanism of the curing test blocks was analyzed. The results show that the optimal mass ratio of uranium tailings curing is 0.08% RD curing agent and 15% cement. Under the optimal ratio, the compressive strength of the curing test blocks can reach 3.0 MPa, and the radon exhalation rate is 0.39 Bq/(m²·s). When the thickness of the solidified layer is 10 cm, the radon exhalation rate on the surface of uranium tailings decreases by 81.2%, and the radon shielding effect is obvious. At the same time, the radon exhalation rate on the shielding layer surface did not fluctuate greatly in the artificial simulated environment test, and the stability is good.

In order to solve the problems of poor dam stability and difficult construction of cover system caused by high water content and low strength of fine tailings, a series of field tests of the vacuum preloading method combined with prefabricated vertical drains to reinforce fine tailings were carried out. The surface settlement, layered settlement, lateral displacement, degree of consolidation and pore water pressure of tailings under different spacing of prefabricated vertical drains were analyzed, and vane shear test and bearing capacity test of tailings were conducted. The research results show that vacuum preloading method can accelerate dewatering of tailings, effectively reduce the water content, then improve the strength and bearing capacity of tailings, and the reinforcement effect of prefabricated vertical drains spacing of 1.0 m is better than that of 1.2 m. As a technology with low cost, good effect, safety and environmental protection, vacuum preloading method has a broad application prospect in in-situ dewatering and reinforce of fine tailings.

The experimental study of deep uranium removal by two kinds of special resins was carried out for high nitric acid uranium-containing wastewater in nuclear fuel element plant. The effects of adsorption equilibrium time and acidity, deep uranium removal capacity, and dynamic adsorption performance were investigated. The resin adsorption equilibrium capacity was measured. The results show that, under the conditions of original acidity (about 3 mol/L), static adsorption time for 8 hours, the uranium concentration in wastewater can be successfully reduced to less than 0.05 mg/L by the special resins. Under the conditions of original acidity, dynamic adsorption time for 30 minutes, the concentration of uranium in the first two bed volume adsorption tail liquid of the two resins is about 0.7 mg/L. The resins exceed breakthough point in a short time. It can be considered to increase the kinetic properties of the resin by changing the group type.

An open-pit boron-iron-uranium associated mine in north China was investigated. The gamma dose rate, radon concentration and radioactive aerosol radiation characteristics of the mine were detected and the individual dose estimation was carried out. The results show that the gamma external irradiation of the mine is mainly concentrated in the vicinity of gravity separation rocker, belt filter, product warehouse and contaminated vehicles and grinding machines. The hazards of radon internal irradiation mainly exist in the leaching plant, and there is no aerosol hazard. The enterprise should strengthen the training of operators of rocking table and belt filter to reduce the residence of personnel in automatic operation, the product barrels should be covered in time, the contaminated equipment should be detected and cleaned in time, ventilation should be strengthened for leaching plant.

The radioactive environment of a decommissioned uranium mine in Jiangxi province was investigated and analyzed. The pollutant sources of the mine and decommissioning management projects were determined. The results show that all the radon exhalation rates of five waste rock heaps exceed 0.74 Bq/(m²·s), moreover, the content of natural uranium and ²²⁶Ra in waste rocks are higher than local background value. The soils of yard and roads are polluted to varying degrees. The content of natural uranium in effluents sampled from four pits are higher than the emission limits of 0.3 mg/L, however, the effluents can reach the emission standard after being treated. The α and β surface contamination level of equipment, pipeline and facilities are all in high level. The value of public maximum individual effective dose contributed by this decommissioned uranium mine before treatment is 5.94×10^-4 mSv/a.

The activity concentrations of ²³⁸U and ²²⁶Ra in soil, and the activity concentrations of ²³⁸U, ²²⁶Ra ²¹⁰Po, ²¹⁰Pb in rice near the uranium mine in Guangxi from 2016 to 2021, were investigated and evaluated. Spearman rank correlation coefficient analysis showed that ²³⁸U, ²²⁶Ra, ²¹⁰Po, ²¹⁰Pb in the soil and rice around the uranium mine had not obviously changed from 2016 to 2021. Most of the sampling sites were pollution-free to medium-polluted. The rate of contribution in effective dose to be accumulated decreased in the order of ²¹⁰Po, ²¹⁰Pb, ²²⁶Ra and ²³⁸U, and the USEPA health risk model showed that the total health risk was lower than the unacceptable value.

In order to ensure the safe storage of low-level radioactive waste generated by nuclear technology application activities, combined with the design practice of an urban radwaste repository in a municipality directly under the central government, the design contents of waste warehouse process design, safety protection system, intelligent management and data transmission system were discussed. The design results meet the requirements of Technical specifications for siting, design and construction of radioactive waste repository for nuclear technology application (HJ 1258—2022), reduce the exposure time of the operator and the additional external radiation dose, ensure the nuclear safety supervision of radioactive wastes.