In order to enhance the quality of uranium dioxide products, a comparison and analysis was conducted on the bulk density of uranium dioxide products in both the new and old uranium purification production lines. It was observed that the bulk density of products in the old production line exceeded that of products in the new line. The primary factor contributing to this difference was identified as significant fluctuations in crystallizing agent concentration of the new production line, resulting in inadequate crystallization effects for uranyl ammonium tricarbonate and smaller crystal sizes, consequently impacting crystal calcination effectiveness. As a result, there was a decrease in uranium dioxide product density and overall product quality. To address this issue, several measures were implemented,such as merging ammonium carbonate preparation positions between the new and old production lines, unifying and localizing crystallizing agent supply, enriching recovered ammonium carbonate solution, and flushing pipeline with steam flushing. These actions successfully resolved fluctuation problems related to crystallization effects within the new production line, leading to an average increase of 5.71% in bulk density of uranium dioxide products as well as an average net weight per barrel increase by 4.73%. Consequently, notable improvements were achieved regarding product quality for uranium dioxide.

The high rates of submersible pump damage due to pump shaft fracture and pump body corrosion have been studied. By conducting theoretical calculations and ANSYS numerical simulations, the mechanical properties such as strength and stiffness of hexagonal and cylindrical shaft structures were compared. Field comparison tests on the corrosion resistance of 304, 316L, and 904 stainless steel materials were also carried out. The results indicate that under the same load and equivalent diameter conditions, the shear stress on the cross-section of the cylindrical axis is 64.95% of the hexagonal axis, and the torsion angle is only 56.25% of the hexagonal axis torsion angle; the simulation results show that the maximum circumferential deformation of the cylindrical shaft coupling is 68.4% of the maximum circumferential deformation of the hexagonal prism shaft, the cylindrical shaft structure exhibits better torsional performance. While 904 stainless steel has the best corrosion resistance, both 304 and 316L stainless steels demonstrate similar corrosion resistance to acidic media. Considering corrosion resistance margins and manufacturing costs, it is recommended to use a cylindrical pump shaft structure and continue using 316L stainless steel as the main material in the development of submersible pumps for uranium mining.

Radioactive decontamination is an important technical means to ensure the sustainable development of nuclear industry. Radioactive decontamination is not only related to the comprehensive cost of operating and managing facilities such as nuclear power plants, and the development of radioactive mineral resources, but also related to personnel safety and social environmental safety, and should be given sufficient attention. On the basis of summarizing various radioactive decontamination technologies commonly used in the process of decommissioning and maintenance of domestic nuclear facilities, the application conditions, advantages and disadvantages of physical decontamination, chemical decontamination, electro oxidation decontamination, microbial decontamination and smelting decontamination technologies are analyzed, and the technical pain points and development direction of decontamination technology is proposed.

Fengcheng paigeite deposit is a large scale multi-metal deposit containing boron, iron and uranium, which is developed by open-pit mining, following by beneficiation (gravity separation, magnetic separation, and flotation) and hydrometallurgical treatment to obtain iron concentrate, sodium borate, and diuranate as products. In this process, several kinds of solid waste are produced such as mining waste rock, beneficiation tailing, and leached uranium tailing. Through detailed investigation of the radioactive characteristics of product and solid waste in the full process, it is indicated that iron concentrate and sodium borate meet their radioactivity quality standard. Mining waste rocks, beneficiation tailing, gravel and coarse sand produced by crushing of ore, and boron mud can be treated and disposed as ordinary solid waste other than radioactive waste. Gravel and coarse sand can be used as building materials. Boron mud is used to produce sub-nanomater silica stone without any limitation related to radioactivity, in case of the boron mud addition not exceeding 50%. Leached uranium tailing should be disposed as extremely low level radioactive waste.

The well washing process of in-situ leaching uranium mine is an important means to increase the amount of drilling water. However, a large amount of impurities such as sediment in the well washing wastewater cause the bag filter and adsorption tower pressure to rise, which indirectly affects the production progress. Based on the principle of centrifugal force, a sand removal device for well washing wastewater was developed and applied in a certain in-situ leaching uranium mine. The results show that it can reduce the pressure of bag filter and adsorption tower, reduce the frequency of filter bag replacement, increase the adsorption water and increase production capacity. The sand removal device of the well washing wastewater has a certain popularization value in the drilling and well washing technology of in-situ leaching uranium mine.

Clay is a crucial component of the coexisting radioactive waste cover layer. The investigation of its shielding performance is of significant importance. In this study, the effects of clay type, clay moisture content, emulsion type, clay+geomembrane on radon shielding were studied by means of self-designed experimental apparatus. The results show that montmorillonite stands out as a clay type with relatively superior shielding capabilities, montmorillonite with 25% moisture surpassed other moisture levels, montmorillonite combining either polyurethane emulsion or geomembranes can yield favorable shielding effects. This research provides essential data and theoretical guidance for the utilization of clay in radon shielding.

Part of the waste residue generated during the development and utilization of rare earth resources belongs to the associated radioactive solid waste. The safe and effective disposal of this type of waste residue is an urgent problem that needs to be solved in the current development of the rare earth industry. By the method of investigation and analysis, based on the types and sources of rare earths, statistics were conducted on the types, yields and radioactive nuclide activity levels of waste generated during the mining and selection process. Combined with the development plan of the rare earth industry, the stock and increment of rare earth waste in typical provinces(autonomous regions) were preliminarily estimated. And the current status and existing problems of the treatment and disposal of rare earth associated radioactive waste residue were sorted out. On this basis, a strategy for regional landfill disposal is proposed: it is recommended to implement a 7+x model nationwide, and to build rare earth waste residue warehouses in major rare earth provinces(autonomous regions), with reference to the model of Baotou in Inner Mongolia, to collect and dispose of rare earth associated radioactive waste residues in the provinces(autonomous regions). Based on the estimated amount and increment of waste residues, suggestions for the scale of rare earth waste residue disposal in each province(autonomous region) are provided.

The fine management model was introduced in a “CO₂ + O₂” in-situ leaching uranium mine in Inner Mongolia, and the processes of adsorption, leaching, acidification and precipitation which affect the quality of production were carefully managed. The preparation of eluent was optimized from “settling mother liquor + sodium bicarbonate + hydrochloric acid + sodium chloride” to“settling mother liquor + sodium bicarbonite + water”, the pH of eluent was maintained at 9.5 ~ 10.0, and reducing the accumulation of chloride ion in the system. The peak mass concentration of uranium in the eluate was increased and maintained at 80~130 g/L. The amount of hydrochloric acid added in the acidification process is automatically controlled, the pH is accurately controlled in 4.5~4.6, and the ratio of carbon to uranium in the qualified liquid is further reduced. Adjust the flow rate of leachate to keep the average mass concentration of uranium in 30~70 g/L, to reduce the influence of mass concentration of uranium on product quality. Control slurry precipitation time, to improve slurry pressure filtration effect. After the optimization of production parameters, the moisture content of the product decreased by 8.50%, the uranium content increased by 2.88%, and the product quality was improved as a whole.

This study conducted γ-radiation cumulative dose monitoring and instantaneous monitoring of γ-radiation air absorption dose rates at 31 monitoring locations around the Fangchenggang nuclear power plant, analyzing the radiation level monitoring results to grasp the long-term changes in terrestrial radiation levels around the nuclear power plant. The results show that from 2018 to 2023, the environmental γ-radiation cumulative dose rate monitoring values around the Fangchenggang nuclear power plant ranged from 62.5 to 141.3 nGy/h, with an average value of 99.1 nGy/h; the instantaneous dose rates ranged from 55.0 to 119.5 nGy/h, with an average value of 93.7 nGy/h. The terrestrial environmental radiation levels around the plant remained consistent before and after the commercial operation of its three units, with both γ-radiation cumulative dose rates and instantaneous dose rates maintained at normal levels, indicating that the emission of airborne effluents during the operation of the nuclear power did not impact the radiation levels in the surrounding environment. There was significant variation in the γ-radiation cumulative dose rates at different monitoring points, with a tendency for higher levels in winter and lower in summer, suggesting that γ-radiation cumulative dose rates are greatly influenced by environmental factors.

In addressing the adsorption issue of low-concentration uranium in nitric acid systems, a chloromethylated styrene-divinylbenzene copolymer was employed as the framework, and phosphorylation was achieved using phosphorus trichloride as the functionalizing reagent. Through Friedel-Crafts alkylation and quenching-hydrolysis/alcoholysis reactions, long-chain hydroxyl and alkyl groups were grafted onto the resin, resulting in uranium adsorbents featuring phosphoric acid and phosphoric ester functional groups, respectively. The resin structural characterization was conducted using infrared spectroscopy, elemental analysis, and thermogravimetric analysis. During the resin preparation, the impact of different process parameters on the phosphorus content and uranium adsorption performance was investigated, leading to the determination of optimal synthesis conditions. Static experiments were performed to assess the influence of pH, equilibrium uranium concentration, and adsorption time on the uranium adsorption properties of the resin. Additionally, a selection of desorption agents and verification of resin reusability were carried out. The results indicate that the prepared phosphoric ester-based uranium adsorbent exhibits excellent adsorption performance for low-concentration uranium (<20 mg/L) in a simulated solution (1 mol/L HNO₃+1 mol/L NaNO₃). The resin saturation adsorption capacity for uranium is 21.9 mg/g dry resin, and the residual uranium concentration in the leachate after adsorption is <0.05 mg/L. Using 0.4 mol/L NaHCO₃ and 0.1 mol/L Na₂CO₃ as composite desorption agents, the desorption efficiency for uranium reaches 98.3%. The synthesized phosphoric ester-based uranium adsorbent proves effective for the adsorption and separation of low-concentration uranium in nitric acid systems.