Studying the migration and diffusion of radionuclides plays an important role in emergency decision making and accident mitigation of floating nuclear power plants. Based on the CALPUFF model, this paper simulates the spatial distribution and concentration distribution of airborne radionuclides ¹³¹I diffusion under the conditions of sailing and power supply under LOCA (Loss-of-Coolant Accident) of the floating nuclear power plant, and the influence of four meteorological parameters, namely wind speed, cloudiness, temperature and air pressure, on the migration was analyzed using sensitivity analysis. The results show that the wind direction affects the diffusion direction of ¹³¹I, and the concentration of ¹³¹I decreases with the increase in the diffusion distance; under the same conditions, the radionuclides diffuses farther and the affected area is larger under the sailing condition. Wind speed is the dominant factor affecting the diffusion of radionuclides, followed by the cloud amount parameter, temperature parameter, and air pressure parameter. The research results can provide theoretical support for emergency responses to nuclear accidents in offshore floating nuclear power plants.

This paper presents the response of a commercial off-the-shelf complementary metal oxide semiconductor (CMOS) active pixel sensor (APS) module to γ-rays delivered from Cobalt-60 at a high dose rate, and evaluates its performance as a potential high-dose-rate and wide range γ-ray detection device. The experimental results show that the rate of noise generation is not linear with respect to the total ionizing dose, and the radiation damage sustained by the sensor modules exhibits a total ionizing dose threshold. A conservative value of this threshold for the test sensor is 38 Gy. In addition, the average pixel gray level value and the proportion of pixels responding to radiation increase with increasing dose rate, and linear responses are obtained for both in the dose rate range of 5.24 to 69.24 Gy/h. the upper limit of the linear radiation response range depends on the capability of the COTS sensor module, while the lower limit depends on the number of radiation response events in a frame, and the upper limit of the linear response range can be increased by reducing the integration time. This work provides valuable suggestions for adopting CMOS-APSs for high-dose-rate and wide range radiation detection, and it is an important complement to our previous studies focused on the linear response of the CMOS-APS under low-dose-rate irradiation.

In this study, we propose a parallel processing method for analyzing video-image radiation-response signals and suppressing radiation noise. We studied the linear-representation law of various image-information components on the radiation dose rate. Subsequently, the simulation images were used to examine the response-signal extract and radiation-noise suppression. The results indicate that the majority of response signals in the global image comprise forward superposition. The peak signal-to-noise ratio of the red channel was significantly improved when the noise signal-substitution algorithm and median filter were applied successively. Real-time radiation dose-rate measurements and clear images under irradiation can be obtained simultaneously.

This study investigates the radiation damage and radiation reinforcement of the control and sensing systems of nuclear robots. Radiation experiments were conducted on key electronic devices to study their radiation resistance, and a shielding structure for radiation reinforcement was designed to meet the radiation resistance performance requirements of the system. The results show that at doses exceeding 1300 Gy, Hall sensors, pressure transducers, and temperature transducers exhibit radiation damage. At doses exceeding 170 Gy, transformers and controllers also show radiation damage. Lithium batteries remain largely unaffected, but packs experience voltage decline. When using Pb and W as shielding materials for Super MC simulation, it was found that at a thickness of 15 mm, the shielding efficiency of the controller and transformer under Pb shielding increased by approximately 84.99% and 52.00%, respectively, compared to 92.23% and 74.47% under W, which had the best shielding effect benefits. By adopting radiation-resistant shielding reinforcement, we can effectively improve the radiation resistance of the controller and transformer. This is crucial for ensuring the reliable operation of nuclear robots in high-radiation environments and providing important data and theoretical support for the development of related technologies.

This paper examines a method and scheme for optimizing the allocation of nuclear radiation monitoring resources, based on the analysis of the risk of nuclear security events and the importance of facilities in a spent fuel reprocessing plant. By constructing a nuclear security radiation accident tree for a plant, the importance of different security events was calculated using fuzzy mathematics and expert scoring methods. The importance of each facility was determined by establishing a fuzzy comprehensive decision model, and a resource allocation scheme for nuclear radiation monitoring was proposed based on the importance level of facilities. The research findings demonstrated that the extraction process plant in the main process area, and the centralized control room in the front area of the plant, were of highest importance. Accordingly, three levels of nuclear radiation monitoring programs were established based on the importance of each facility. This study offers theoretical and technical support for the safety management and operation of a spent fuel reprocessing plant. Additionally, the analysis results can serve as a reference for allocating nuclear radiation monitoring resources in various facilities in a reasonable manner.