The measurement of tritium activity concentration in high-purity ³He gas products imposes stringent requirements on the detection limit and sample consumption of analytical devices. To address the requirements for measuring tritium activity concentration in high-purity ³He gas, this study developed an analytical device using a proportional counter as the detection component through structural design and material optimization. The key parameters of the device, such as plateau characteristics, detection efficiency, and detection limit, were systematically evaluated. The results show that the plateau length of the device is 150 V with a plateau slope of 4.31% per 100 V. The measured tritium signal spectrum shows significant differences from the background signal spectrum. The detection efficiency for tritium reaches 66.78%, and the detection limit is 2.55 Bq/L, with a sample consumption of only 2 mL per measurement. The device demonstrates reliable performance and provides effective technical support for accurate tritium measurement in high-purity ³He gas.

To comprehensively know well the frequency of CT application and distribution characteristics of examinees in Hongkou District, Shanghai city, and to provide data support for further improving medical radiation protection and guiding the rational application of CT examination, a survey method was used to create a unified survey form. The CT examination items included 8 examination positions, including head, chest, abdomen, spine, pelvis, limbs, CT intervention, and others. According to the age group division method proposed by UNSCEAR, they were divided into 3 age groups: less than and equal to 16 years old, 16-40 years old, and over 40 years old. The survey data will be firstly obtained from the medical institution information system for the number of CT examinations from October 1, 2022 to September 30, 2023. Secondly, manual recording will be selected and further statistics will be filled in the survey form. Excel software will be used to summarize and analyze the data. A total of 11 medical institutions in Hongkou District conducted CT examinations, including 3 class-A hospitals, 4 secondary hospitals, 1 primary hospital, and 3 unclassified hospitals. There were 27 CT devices and 39.3 CT scans per million population. In 2023, the total number of CT scans was 934 653, with an annual application frequency of 1 359 person times per thousand population. The most commonly used scanning area was the chest, accounting for 57.20%, with the top five scanning areas totally accounting for 94.40%. The overall male to female ratio of CT scans in 2023 was 0.96∶1, with slightly more female examinees than male examinees in the main types of examinations such as head, chest, abdomen, spine, and limbs. All types of examinations showed that the total proportion of examinees over 40 years old accounted for 82.19%. In 2023, CT scans in Hongkou District were mainly conducted in secondary and class-A hospitals, with the majority of examinees being over 40 years old, slightly more female than male examinees. The frequency of application has increased by 4.5 times compared to the application frequency of 304 person times per thousand population in Shanghai in 2016. Therefore, it is particularly important to strengthen the justification assessment and protection optimization of CT examinations to reduce unnecessary radiation exposure risk.

The dose estimation of acute exposure can no longer be ignored. International organizations such as the IAEA have recommended dosimetric quantities specifically applicable to dose estimation of acute exposure and related emergency response actions. Currently, China faces considerable shortcomings in this field, the urgent basic need is the dose estimation method for acute exposure. Based on the scientific foundation of radiation protection and the latest international research achievements, the national standard GB/T 46475—2025 titled "Estimation Method for Weighted Absorbed Dose of Acute exposure" has been developed through a three-year effort. This standard establishes the principles for estimating relative biological effectiveness (RBE)-weighted absorbed doses for acute exposure and describes the estimation methods, including acute exposure pathways, RBE values for evaluating deterministic effects, internal exposure dose estimation, and external exposure dose estimation. It can provide technical support for dose estimation and emergency protection actions in nuclear and radiation accidents involving acute exposure.

The resuspension of radioactively contaminated soil particlesfollowing disturbance affects human health through inhalation and leads to the spread of pollution, thereby increasing the difficulty of prevention and control. However, existing research on the microscopic mechanisms of resuspension is insufficient to provide reliable parameters and model corrections for radiation impact assessments. This paper reviews the resuspension of radioactively contaminated soil particles, with an emphasis on the physical mechanisms involved in particle resuspension and the current research status of mainstream DEM-CFD coupling algorithms. The primary technical bottlenecks in existing studies include the high complexity of microscopic resuspension scenarios, insufficient accuracy in multi-scale coupling, low computational efficiency, and challenges in validation under real-world conditions, resulting in current models only capable of roughly estimating resuspension source terms in practical applications. Future research should focus on the development of complex microscopic models, high-performance optimization of multi-physics coupling, and quantitative validation in actual scenarios, thereby providing more reliable references for engineering applications.

Based on the theory of collaborative governance, focusing on prefecture-level cities in non-nuclear facility provinces in the central region, and taking the coordination mechanism of nuclear and radiation emergency response as the research starting point, this study systematically reviews the current operational status of the collaborative emergency response mechanism in a specific prefecture-level city, and analyzes the structural challenges and unique risk characteristics it faces in actual responses. On this basis, it proposes a coordination path for the in-depth integration of nuclear and radiation emergency preparedness into the regular "comprehensive emergency" management system, and constructs an appropriate performance evaluation system. The purpose of this research is to improve the systematicness and response efficiency of grassroots emergency management, promote the realization of the goal of "rapid response and efficient handling", and provide a reference for similar regions to improve their nuclear and radiation emergency coordination mechanisms.

To ensure long-term reliability of metrological performance of vehicle-mounted radiation monitoring system and to address the impracticality and high cost associated with frequent off-site calibration, This study proposes and validates a user-performed on-site calibration scheme. Using the widely adopted RS-700 vehicle-mounted radiation monitoring system as the test object, with standard radioactive sources and a high-pressure ionization chamber as references, the measurement repeatability, data consistancy, and statistical distribution of calibration factors across various distances are systematically evaluated. The results demonstrate the feasibility of user-performed on-site calibration. To ensure calibration accuracy, key operational parameters such as maintaining a distance between the calibration source and the detector greater than 0.5 meters and performing multiple independent measurements should be achieved with the aim to reduce random error.

The nuclear power plant radioactive source composite positioning online monitoring system developed and constructed in this research and development combines the radioactive source management work with Ultra-Wide Band ( UWB) technology and Beidou positioning technology to achieve seamless and high-precision tracking both indoors and outdoors. For outdoor scenarios, the Horizontal Dilution of Precision (HDOP) factor is adopted for evaluation, and Kalman filtering is used to enhance the data reliability. For indoor scenarios, Time Division Multiplexing Access (TDMA) technology is innovatively applied to the UWB Time Difference of Arrival (TDOA) positioning system. This maximizes the concurrent tolerance of the system while achieving a high-precision positioning of ±10 cm, meeting the precise monitoring requirements for the tiny movements of radioactive sources. With the help of 5G real-time transmission dedicated to nuclear power plants, intelligent and digital full-process control has been successfully achieved, ensuring the safety of radioactive source storage, transportation and usage. The introduction of 3D technology enhances the intuitiveness and efficiency of monitoring, providing a new approach for the safety supervision of radioactive sources in nuclear power plants.

To better enhance personal protection awareness of radiation workers and their attention to personal dose monitoring, the external exposure personal dose monitoring data of radiation workers in a certain class—A traditional chinese medicine hospital from january 2021 to december 2024 were analyzed to evaluate the dose differences among different years, working positions, and professional categories. A total of 299 person-times were monitored over four years, with an average annual effective dose of 0.17 mSv/a. There were significant dose differences among different years (P<0.05), with the highest dose in 2021. The dose differences between interventional group and radiological diagnosis group in the nursing position, and between technicians and nurses in radiological diagnosis group were significant (P<0.05). The dose differences between interventional group in the oncology department and those in the cardiovascular department, neurosurgery department, and endoscopy center were significant (P<0.05). There were no significant dose differences between various radiation positions and different professional categories. The results suggest that the annual effective dose of radiation workers in this class-A traditional chinese medicine hospital comply with national standards. It is necessary to continuously strengthen occupational protection training and the promotion of relevant regulations, strictly supervise protective measures in workplace, and ensure occupational health.