To accurately measure the oxidation-reduction potential of uranium ore geological samples, this study try to explore a better measurement method and experimental conditions by comparing and analyzing the application effects of the acidic potassium dichromate method and the alkaline potassium permanganate method in the measurement of the oxidation-reduction potential of uranium ore geological samples. The potential drop method was used to systematically conduct a multi-dimensional comparison between the acidic potassium dichromate method and the alkaline potassium permanganate method. The aspects of comparison included solution stability, optimal solution concentration, sample soaking time，solid - liquid ratio, and electrode equilibrium time. The sample soaking time and electrode equilibrium time of the alkaline potassium permanganate method are shorter than those of the acidic potassium dichromate method, allowing it to reach a stable and reliable potential value more quickly. For strongly reducing samples，the ΔEh value obtained by the acidic potassium dichromate method is larger. However, the evaluation conclusions of the two methods regarding the reduction ability of the samples are consistent. Nevertheless, the precision of the alkaline potassium permanganate method is better.The optimal experimental conditions for the alkaline potassium permanganate method are as follows: a concentration of 0.03 mol∙L^-1, a sample soaking time of 1.5 h，a solid-liquid ratio of 1:25, an electrode equilibrium time of 5 min, a reaction medium of 0.2 % potassium hydroxide solution, and a temperature of (25±1) °C. The ΔEh value measured by this method is basically consistent with the judgment results of the oxidation - reduction environment by the oxidation coefficient method (Fe²⁺/Fe³⁺), and is also basically consistent with the color of the samples.Based on comprehensive experimental indicators, the overall performance of the alkaline potassium permanganate method is superior to that of the acidic potassium dichromate method in the measurement of the oxidation - reduction potential of uranium ore geological samples. By adopting the optimal experimental conditions, the accurate measurement of the oxidation - reduction potential of uranium geological samples is achieved, providing reliable technical support for uranium ore geological research.

This study monitored the activity concentrations of radionuclides in seepage water from a decommissioned uranium tailings pond，analyzed the temporal trends of radionuclide concentrations in seepage water from 2020 to 2024，and investigated the correlations between radionuclides in seepage water and monitoring well water to evaluate the radiological impact of seepage on surrounding groundwater. The results showed that the seepage water contained uranium at concentrations ranging from 15.1 to 397 μg·L^-1，²²⁶Ra from 0.008 to 0.176 Bq·L^-1，²¹⁰Pb from 0.007 to 0.172 Bq·L^-1，and ²¹⁰Po from 0.004 to 0.021 Bq·L^-1，levels of ²²⁶Ra，²¹⁰Pb，and ²¹⁰Po are all below regulatory limits. In monitoring well water，uranium concentrations ranged from 0.21 to 2.98 μg·L^-1，²²⁶Ra from 0.006 to 0.023 Bq·L^-1，²¹⁰Pb from 0.004 to 0.131 Bq·L^-1，and ²¹⁰Po from 0.002 to 0.011 Bq·L^-1，all consistent with local background levels. Analysis using the Mann-Kendall test revealed no significant temporal trends for uranium and ²²⁶Ra in seepage water，while ²¹⁰Pb and ²¹⁰Po concentrations exhibited declining trends and become stable. According to the evaluation results of Spearman correlation coefficient, the Spearman correlation coefficient ρ_s for uranium，²²⁶Ra，²¹⁰Pb，and ²¹⁰Po in the seepage water and monitoring well water were 0.314 3，0.074 4，0.939 5，and 0.460 5，respectively. Significant positive correlations were observed between ²¹⁰Pb and ²¹⁰Po in monitoring well water and their counterparts in seepage water. These findings provided critical data and regulatory guidance for authorities and enterprises to strengthen radiation environmental monitoring and implement targeted management strategies, thereby mitigating potential risks to groundwater safety around uranium tailings facilities.

The current research on quantitative assessment of nuclear emergency response plans suffers from the lack of a systematic assessment framework and methodological limitations，which are manifested in the fragmentation of assessment dimensions，weak relevance of the indicators，and significant subjective cognitive bias，resulting in serious constraints on the comparability and reproducibility of the results of the assessment. The current assessment situation is difficult to meet the urgent needs of nuclear emergency rescue teams for the continuous improvement of plan quality， especially the lack of effective quantitative tools for key performance indicators，such as the timeliness of plan response and the rationality of resource allocation. To address the kennel problems of discrete index system and strength the subjectivity in the evaluation of nuclear emergency rescue teams’emergency plans，this study constructs a multi-level quantitative assessment system for emergency plan quality based on the theory of complex adaptive systems，and the fusion of heterogeneous data from multiple sources and optimisation strategy of model integration. At the level of theoretical construction，this study firstly deconstructs the professional characteristics and operation mechanism in the process of nuclear emergency plan preparation. Combined with the empirical data accumulated during the regular operation and maintenance of nuclear emergency rescue teams，a three-dimensional assessment framework was innovatively proposed. The framework systematically integrates the core assessment dimensions such as normative principles，structural integrity requirements and content coverage，forming a hierarchical assessment system oriented to continuous quality improvement. In terms of methodological innovation，this study adopted the deep coupling strategy of hierarchical analysis method (AHP) and fuzzy comprehensive evaluation method (FCE) to construct a hybrid assessment model with dynamic correction function. Through the structured indicator system design method，a stepwise evaluation system containing 6 first-level indicators (system architecture， response process，resource allocation，training and rehearsal，information management，and continuous improvement) and 23 second-level indicators (e.g.，completeness of command system，timeliness of emergency response，and rate of equipment configuration up to the standard，etc.) has been established. Among them，the AHP module completes the allocation of indicator weights by constructing a 1-9 scale judgement matrix，focusing on solving the problem of quantifying the structural relationship between multi-level indicators；while the FCE module applies the trapezoidal affiliation function to achieve the quantitative conversion of qualitative indicators，effectively reducing the bias of subjective judgement. The model validation process adopts a dual testing mechanism：the theoretical level is to test the structural validity of the indicator system through expert argumentation; the practical level is to select a national nuclear emergency rescue team to carry out empirical research. Example analyses show that the model can accurately identify the weak links of the preplanning system.The quantitative assessment system constructed in this study has gotten breakthroughs in three aspects：First，the establishment of a multi-dimensional evaluation framework of ‘standard compliance-process rationality-performance compliance. Second，the development of a hybrid AHP-FCE algorithm; and third，the innovation of a dynamic correction mechanism，so that the model can automatically optimise the indicator structure with the changes in the emergency environment. The study provides methodological support for the construction of China’s modern assessment system of nuclear emergency response capability，which has important theoretical value and practical guidance significance. Subsequent research will focus on expanding the applicability of the assessment model in the scenarios of nuclear emergency response collaboration and new reactor applications，and continue to improve the universality and accuracy of the model.

The rock fragmentation mechanism of worn disc cutters provides theoretical guidance for TBM cutter changing. To investigate the correlation between cutter force and penetration depth，evaluate rock fragmentation efficiency，and elucidate the fragmentation mechanism of single worn cutter in extremely hard rock conditions，different blade widths were utilized to represent different wear levels. This study employed sequential indentation tests using both a new cutter with blade width of 17 mm and worn cutters with different blade widths on Beishan granite specimens with dimension of 420 mm×400 mm×500 mm. The penetration process，force characteristics，rock fragmentation volume，and specific energy were systematically analyzed. The key findings include：1）Both new and worn cutters exhibited consistent rock failure phases - initial compaction followed by linear deformation，with intermittent force drops during single penetration, 2）During sequential penetrations with the same depth for the new cutter，both the maximum penetration force and the force growth rate in linear-deformation stage demonstrated an initial increase then decrease, 3）Worn cutters with larger blade widths required higher average force per unit penetration depth. For each kind of worn cutter，the force-depth ratio of each penetration showed fluctuating tendency during the whole sequential penetration process，confirming the cyclic process of energy accumulation，release and then re-accumulation, 4）Specific energy increased linearly with blade width while the penetration capability decreased correspondingly. The 18 mm-blade cutter exhibited optimal rock fragmentation efficiency and penetration performance in sequential penetration.

In order to understand the current situation of the air absorption dose rate level from terrestrial γ-radiation in Yinchuan, master the distribution pattern of surface γ-radiation，evaluate the external exposure level of residents，gradually establish and improve the environmental radiation background database of the whole city of Yinchuan，Ningxia，and provide technical support for ensuring the health and safety of the public and the development of urban construction，and provide a basis for government decision-making, Evenly measuring grid method was used to cover the measurement area of the air absorption dose rate of surface γ-radiation in Yinchuan city. The dose rate levels of different administrative regions，different environmental conditions，different soils and materials in Yinchuan city were collected and summarized, the effective dose received by residents was estimated. The survey results indicate that the average terrestrial gamma radiation absorbed dose rate in Yinchuan (after deducting cosmic ray contributions) is 48.67 nGy·h^-1，primarily attributed to ⁴⁰K. This value closely aligns with the regional average in Ningxia Hui Autonomous Region but is significantly lower than the national average. The resultant annual effective dose to the public is calculated as 0.30 mSv，which is lower than both the per capita annual dose from terrestrial radiation in China (0.46 mSv) and the outdoor gamma radiation dose in Ningxia (0.55 mSv).

CO₂ is the main component of non-condensable gas in high-temperature geothermal fluid and its existence still have important impact on geothermal development. Determining its content in high-temperature geothermal fluid is of great significance for geothermal development. The conventional sampling and testing analysis of CO₂ content determination has some drawbacks, such as insufficient sampling representativeness，cumbersome implementation process and high sampling cost. Based on the pressure-temperature measurement in the wellbore during discharge tests and two-phase flow calculation, this paper proposed a new method to determine CO₂ content in the geothermal reservoirs. This method only uses a large number of relatively reliable measured data of temperature and pressure, it has low cost, strong practicability and good reliability. This paper first describes the pressure-temperature measurement during discharge tests. Then constructs a model that solves the two-phase flow in the geothermal wellbore, which was verified by comparison with the commercial software WELLSIM, and determine CO₂ content by using both the wellbore pressure-temperature measurement and model calculation data. Finally, the method was tested and verified by using the measured data from Gulu geothermal field in Tibet and the Ziledaer geothermal field in Turkey, and the CO₂ contents in the geothermal reservoir were determined to be 1.1 % and 3.2 % respectively.

Hydrogeological conditions are crucial for the site selection and long-term safety assessment of high-level radioactive waste (HLW) disposal repositories. This study focuses on the groundwater circulation characteristics of Xinchang preselected site and its southern periphery of the Beishan area for HLW disposal. A comprehensive approach employing multiple environmental isotopes, hydrodynamics, and numerical modelling was used to investigate groundwater circulation within the study area. Results indicated that groundwater in shallow loose sediments exhibited relatively rapid renewal rates, with an average age generally less than 30 years. The apparent ¹⁴C age of deep bedrock groundwater generally exceeding 10 ka within the underground research laboratory (URL) site. There was no evidence of contributions from deep crustal or mantle sources to groundwater within the region. Within the Xinchang site, the groundwater head shows pronounced vertical stratification, with a higher hydraulic head in shallow zones than in deeper ones. Groundwater in boreholes distant from the gully shows weak hydraulic connectivity with precipitation, and the groundwater level often exhibits periodic fluctuations. The groundwater flow systems can be categorized into three types: regional, intermediate, and local. The local flow system was the most active, accounting for over 80 % of the total flux. These characteristics showed that the hydrogeological conditions in the study area were favorable for the geological disposal of HLW.

As the field verification standard for radioactive measuring instruments such as gamma loggers in uranium exploration work，radium sources have played a good role in controlling the metrological performance of the instruments. However，due to national security and environmental protection policies，the existing number of solid radium sources in China can hardly meet the increasing demand of uranium exploration workload，and there is an urgent need to carry out the development of alternative verification devices. It is planned to use natural uranium ore powder and other materials to develop verification devices to verify the radioactivity measuring instruments during the period. Based on the theory of γ radiation field，the relationship between the geometry of the verification device and the internal γ field was calculated，and it was experimentally verified that an annular column verification device with an internal bore diameter of 50 mm and an axial length of 600 mm can ensure that the center of the verification device has a saturated plateau area of 200 mm，leaving at least 100 mm redundancy for convenient detector placement. The internal irradiation volume rate is positively correlated with the thickness of the horizontally oriented ore layer before the saturation thickness is reached. The practical geometry of the γ logger verification device was determined by theoretical calculations，avoiding the waste of material and time in a large number of conservative designs.

More than 60 years of uranium exploration has accumulated a lot of knowledge. Traditional technical means and management measures can hardly meet the business development needs of the information age. The knowledge service and information management model in the field of uranium exploration urgently needs to be upgraded. This paper focuses on the building of an integrated knowledge platform for collecting, managing and analyzing various types of information related to uranium deposit，especially the key process of the construction of uranium exploration knowledge base and its application in the field of uranium geological exploration. The content of the knowledge base was enriched by two ways of manual upload and automatic acquisition and import. After launch, the repository will be prompted in all the member units of the CNNC so to realize the knowledge preservation, management and application in the scientific and effective sharing way, and transformation of knowledge and information management model in uranium exploration field.

Qaidam basin，located at the northeastern margin of the Qinghai-Tibet Plateau，is one of China’s major large-scale oil- and gas-bearing basins. The results of uranium exploration in recent years show that it has good prospects of uranium mineralization. However，compared to the western Qaidam basin，research on the fundamental geology and uranium exploration in the eastern Qaidam basin remains relatively underdeveloped. Based on systematic summary of low-temperature thermochronological data，provenance and growth strata characteristics，the Cenozoic tectonic evolution history of the east Qaidam area was reviewed. We investigated the control of Cenozoic structural evolution on uranium mineralization in the eastern Qaidam，through comprehensive analysis of typical uranium occurrences surface (field observations) and near-surface (seismic profiles) data. The results indicated that fault systems exert primary control over uranium mineralization，with uranium occurrences predominantly distributed within the flank of gentle anticlinal near the thrust faults，and the Olongbulak North Fault and its secondary faults may work as the principal ore-controlling faults. The uranium mineralization in the east Qaidam occurs predominantly by exudative uranium metallogeny，with Carboniferous hydrocarbon source rocks potentially serving as significant provider of abundant uranium for the mineralization processes. The fault systems within the basin provide effective channels and driving force for the upward migration of deep uranium-rich reduction fluid，and the regional intense compression and hydrocarbon generation control the spatial position of uranium mineralization. The findings in this paper are meaningful for the following uranium exploration work in the east Qaidam basin.