Being fast, efficient and widely-covered, airborne monitoring of radiation environment is an irreplaceable technical means in nuclear accident emergency monitoring. To introduce radiation monitoring actions in nuclear accidents at Chernobyl in the Soviet Union in 1986, Three Mile Island in America in 1979 and Fukushima in Japan in 2011. Airborne monitoring of radiation environment plays an important role in radiation contamination area confirmation, radiation environment survey and technical supply to related national department. Therefore, it is an important part of nuclear emergency response. It is suggested to carry out research on new equipment technology for airborne monitoring of nuclear emergency in an orderly manner; to study the analysis and decision of airborne monitoring for nuclear accident emergency; effectively respond to nuclear accidents, to carry out the detailed survey of radiation environment around nuclear facilities throughout the country.

In order to test the practicability and operability of the emergency plan for environmental emergencies of district, the ability of radiation accidents quickly respond, emergency monitoring and disposal of the radiation emergency monitoring team, and to inspect cooperative disposal ability according to the responsibilities stipulated in the plan of police department, health department, and publicity departments, and to further standardize the emergency response procedures for radiation accidents, and carry out radiation accident emergency drills. To describe the radiation accident drill organized by the district and jointly held by environmental protection, police department, health department, publicity and other departments, to analyze the scenario design, emergency equipment, emergency monitoring, on-site disposal, emergency termination, and to summarize and analyze the drill. The drill strictly implemented the emergency response procedures for radiation accidents, and comprehensively verified the nuclear and radiation emergency system in Chang'an District. By relying on the existing national technical force, the drill vigorously coordinated and cooperated to improve the rapid response ability of radiation emergency. The drill is an important way to effectively improve the emergency management ability of radiation accidents, to improve the technical ability of effectively response and emergency disposal of radiation environmental safety, and improve the technical level of the emergency monitoring team. It is also one of the technical means for the effective supervision of radioactive sources. It is suggested to continuously carry out the construction of online supervision capability during the transportation of radioactive sources, to improve the professional qualities and skills of road transport operators and reduce the probability of accidents, and continue to strengthen emergency exercises (drills) and technological innovation.

With the development and utilization of nuclear energy, the safe operation of nuclear facilities has become a social issue of great concern. China attaches great importance to nuclear emergency plan and the construction of legal, institutional, and mechanism systems. Among them, the emergency preparedness and response of airborne monitoring for nuclear emergency is one of the important components of the national nuclear emergency system. The technology system of airborne monitoring for nuclear emergency is being developed and combines the advantages of manned aircraft and unmanned aerial vehicle (UAV) airborne monitoring. In recent years, UAVs with different loads and types have been developed, with diversified sizes and types of detectors carried by UAVs. The research on UAV airborne monitoring techniques for nuclear emergency has been continuously deepened and improved, and the technical system of airborne monitoring for nuclear emergency has been developed at the same time. The construction of UAV airborne monitoring technology system for nuclear emergency is discussed from the perspectives of monitoring equipment and technology, emergency response plan, emergency monitoring and evaluation, monitoring standards, emergency personnel, emergency support, and training and exercise. The UAV is a rapidly developing aircraft. With the continuous improvement in UAV performance and the continuous innovation and development of nuclear emergency airborne monitoring technology, the UAV airborne monitoring technology system for nuclear emergency will be constantly improved and developed towards networking, intelligence, and standardization.

Objective To measure the air-absorbed dose rate of gamma radiation in public areas for the situation of the local radiation environment. Methods Using a large-volume γ spectrometer system with a NaI(Tl) detector mounted on a UAV, we conducted large-scale airborne radiation monitoring in public areas in southwestern China, to measure the air-absorbed dose rate at a height of 1 m from the earth’s surface. Results The airborne radiation monitoring data were used to analyze the local radiation environment. The mean air-absorbed dose rate at a height of 1 m was 43.6 ± 12.9 nGy/h. Seven abnormal radiation points were detected, and two of them were located where construction was ongoing. At one of the abnormal radiation points, FH40G meter measurements showed that the air-absorbed dose rate at a height of 1 m was up to 22.0 μGy/h. Field soil samples were collected for HPGe γ spectrometer analysis: the ²³²Th radionuclide activity concentration was 96.0 kBq/kg, and the ²²⁶Ra radionuclide activity concentration was 9.9 kBq/kg. Conclusion Using the UAV-mounted large-volume γ spectrometer system with NaI(Tl) detectors for large-scale airborne monitoring is a fast and effective method for dragnet monitoring of the level of radiation in public areas.

Objective To develop an unmanned aerial vehicle (UAV)-borne radiation monitoring system with high detection efficiency and nuclide identification ability for airborne monitoring in nuclear emergency. Methods The UAV-borne CeBr₃ radiation monitoring system was composed of four cerium bromide (CeBr₃) crystal detectors coupled with silicon photomultipliers (SiPMs) and other components including integrated modules, intelligent electronic devices, and new composite materials. Results According to various performance tests on the system, the crystal energy resolution was better than 5% (@0.662 MeV), the peak drift of the energy spectrum was within ±1 channel, the linear fit of energy was 0.99997, the change in the count rate of each energy window during 12 h long-term measurement was less than 5%, and the detection efficiency was higher compared with that of NaI (Tl) detectors of the same volume. Conclusion Through ground point source testing and theoretical calculation, the system has reliable ability to identify radionuclides, which can be used in nuclide identification and the preparedness and response for nuclear and radiation emergencies.