China's nuclear emergency technology and equipment research and development go hand in hand after the Fukushima nuclear accident
Source: China Nuclear Industry Magazine Date: 2016-06-13
China's nuclear energy is in a strategic period of comprehensive development. The number of nuclear facilities and activities has increased significantly. Strengthening nuclear emergency work, especially strengthening the research and development and deployment of nuclear emergency technologies and equipment, is an important part of ensuring nuclear safety. The nuclear emergency caused by natural disasters such as the Fukushima nuclear accident shows that nuclear emergency technologies and equipment are essential to nuclear emergency work.
Fukushima nuclear accident experience and inspiration
The Fukushima nuclear accident in 2011 caused serious impacts in the international arena. The lessons of this accident mainly related to the targeting of external disasters, severe accident management, and emergency preparedness. China also gained valuable experience and feedback.
Operational units of nuclear facilities should carry out emergency preparations for extreme natural disasters. The emergency plan (or emergency plan) should fully consider the in-depth defense of extreme external natural disasters, and should consider the nuclear emergency capability of coping with common causes of multiple units under the conditions of extreme natural disasters and multiple disasters; the reliability of safety systems and emergency equipment should be improved The emergency response center should have the ability to resist external disasters and corresponding protection, can obtain safety-related parameters and have corresponding communication capabilities; should have sufficient resources to respond to multi-unit accidents, including personnel, equipment, materials and external support, and improve Training in response to severe accidents; establishing an effective on-site radiation protection system to cope with severe accident conditions.
National and group-level emergency support capabilities need to be strengthened. In the case of a serious accident, the emergency organization of the nuclear facility operating unit may not be able to complete the emergency response task independently, which requires the coordination of national and group emergency forces. Therefore, the ability to integrate resources at the national and group levels and the support capabilities of technical support agencies should be enhanced, and a national-level nuclear emergency response capability should be established in the area of nuclear accident mitigation and radiation consequences management.
Enhance nuclear emergency technology capabilities. Fukushima nuclear accident emergency response experience shows that nuclear emergency assessment integrated system, multiple emergency monitoring methods, strong radiation field robots, big data acquisition and analysis and other technologies are necessary capabilities in the emergency response process of nuclear facilities.
Information release and public communication are important components of a nuclear emergency response. Public protection measures shall be timely and accurately communicated to the public through a unified information channel. The Fukushima nuclear accident also highlighted the importance of radiation protection knowledge. It is important to study training, education, and communication methods to enable the public to understand radiation exposure and nuclear accidents correctly. Practical measures should be taken to enable the public to understand radiation and its effects, and to establish good communication with the media.
R & D status of nuclear emergency technology and equipment in China
1. Development of China's nuclear emergency basic technology
From the late 1980s, China has gradually established a system of laws and standards based on international experience, and has been applied to nuclear power plants first, and gradually expanded to other nuclear facilities. After the Fukushima nuclear accident, China has improved the methods of emergency planning area division, emergency action level, and operation intervention level formulation, established related technologies and software, and has been widely used in nuclear power plants.
Planning method of emergency planning area. To determine the emergency planning area, first consider the type of nuclear facilities and their hazards, such as the power of a nuclear power plant, and consider design basis accidents and serious accidents in the analysis so that emergency preparedness in the identified emergency planning area can respond to the severity Different accident consequences. At the same time, factors such as the specific environmental characteristics surrounding the nuclear facility (such as topography, administrative demarcation boundaries, population distribution, transportation, and communications), socioeconomic conditions, and public psychology should also be considered. For this reason, the emergency planning area can determine the actual shape according to the site characteristics and surrounding administrative jurisdiction, so that the actual boundary of the delineated emergency planning area conforms to the local actual situation, which is convenient for emergency preparation and emergency response.
Nuclear Power Plant Emergency Action Level (EAL) research. The level of emergency operations is the main basis for entering the emergency state in the event of a nuclear accident. Based on the United States Nuclear Regulatory Commission (USNRC) emergency action level development methodology, China has also made reference to the IAEA's accident assessment procedures and other relevant technical documents, and combined with the characteristics of China's pressurized water reactor nuclear power plant site, has achieved certain results in the formulation and application of EAL Experience. At the same time, with reference to the experience of pressurized water reactor nuclear power plants, China has established a level of emergency operations for heavy water reactor nuclear power plants.
Oil formulation and software development. The calculated value of the operation intervention level of a nuclear power plant needs to be determined in combination with the source of the severe accident, the typical meteorological conditions at the site, the shielding factor of the house, and the annual residence factor of the person. Because the default OIL values are calculated based on environmental conditions such as hypothetical accidents and meteorology, when actual accidents occur, corresponding corrections need to be made based on actual environmental monitoring results. The nuclear power plant operation intervention level software system is to realize the operation intervention level calculation based on the current meteorological conditions and release source terms when the nuclear power plant accident occurs, and the operation intervention level calculation based on environmental monitoring data; at the same time, it can also be applied to Nuclear power plant exercises and training.
2. Nuclear accident emergency assessment system
China has more than 20 years of history in the development of emergency assessment and decision support systems for nuclear accidents. The development of the system has been synchronized with related technologies in the fields of information technology, computing power and radiation protection.
Nuclear accident emergency assessment and decision support system has technical research capabilities from accident condition diagnosis, release source term, wind field and diffusion simulation, radiation dose calculation, food chain analysis, protection countermeasure analysis, etc., and has been used in domestic nuclear power plants, research reactors and nuclear fuel More than a dozen sites including recycling facilities have practical application experience, and the system has been applied during national nuclear emergency exercises.
In 2015, China Academy of Radiation Protection completed the development of a nuclear emergency assessment system for uranium enrichment facilities, realizing real-time assessment of nuclear criticality accidents and UF6 leakage accidents. The system used chemical model and heavy gas model for the first time in China for emergency assessment of UF6 leakage accidents. The system implements functions such as WebGIS display of evaluation results, query of historical evaluation results, and system management for three evaluation modes: real-time evaluation mode, interactive evaluation mode, and exercise mode.
3. Vehicle, ship and airborne nuclear emergency monitoring integrated system
Quickly obtaining accident radiation monitoring data is a requirement early in the accident, and it is also the prerequisite and basis for making scientific emergency decisions. China's nuclear industry-related research institutes have developed integrated systems for on-board and ship-borne nuclear emergency monitoring, including nuclear emergency inspection vehicles, on-board or ship-borne radioactive laboratories, and so on.
In the case of a serious nuclear accident, a nuclear emergency patrol vehicle can obtain radiation monitoring data through rapid patrol along the highway. The nuclear emergency radiation inspection vehicle system can maneuver, effectively collect, store, analyze, process and publish radiation information from different regions, and display it in the system intuitively. The nuclear emergency patrol vehicle can send large-scale NaI detectors in combination with positioning systems and wireless data communication systems to quickly send on-site dose levels, nuclide information, and location information to nuclear and radiation events in real time. Emergency Command. At the same time, nuclear emergency inspection vehicles can also be equipped with environmental radiation inspection instruments, in-situ gamma spectrometers, samplers, etc., to expand emergency monitoring functions.
The plutonium mobile laboratory was developed along with the measurement analysis and patrol technology of samples at the nuclear accident site. The mobile laboratory can perform on-site analysis of samples collected during a nuclear accident, and can also directly monitor the environment of a nuclear accident site to quickly grasp the radiation level and pollution distribution at the site. The mobile laboratory can integrate the gamma dose rate on-line monitor system, aerosol on-line measurement system, on-board meteorological measurement instrument, and sampling and protective equipment.
The nuclear industry system has established a NaI (Tl) spectrometer system and an HPGe spectrometer system for aviation emergency monitoring, and has established a corresponding real-time data transmission system, which has a relatively fast response capability for nuclear emergency aviation monitoring, and the corresponding system. Calibration capability.
4. Nuclear emergency protection technology research and equipment development
In terms of external radiation dose monitoring and management, based on the advancement of communication technology, an emergency external radiation dose monitoring system capable of real-time remote monitoring has been developed.
In terms of internal exposure monitoring, based on the mobile whole body counter, an internal exposure emergency living body monitoring system including a thyroid counter and a whole body counter was developed, and it has a corresponding data management system, which can provide rapid internal exposure for the public and staff after nuclear and radiation accidents. Provides in vivo monitoring and dose estimation capabilities.
Dose evaluation and dose reconstruction technology for emergency personnel, analyze the emergency personnel exposure pathways, protective measures, and factors affecting emergency personnel exposure, establish a rapid dose estimation model for emergency personnel, and use the dose prediction and dose reconstruction system for post-accident dose evaluation.
With respect to the biological dose and treatment technology of tritium nuclear accidents, in a certain dose range, a multi-index and multi-method combined bio-dose analysis system can respectively establish and modify the relationship between dose effect and time effect of genes as radiation-sensitive indicators. In recent years, β-ray skin injury treatment technology has been established, and some radiation injury protective agents and transuranic nuclides promoting drugs have been developed.
In the field of nuclear emergency site decontamination technology and device research and development, we have developed special decontamination or decontamination equipment suitable for use in the plant, environment, equipment, and personnel.
5. Development of nuclear emergency robot
In the field of strong radiation field robot development, China Radiation Research Institute and Atomic Energy Institute have successively developed various types of robots. Zhongfuyuan has developed two types of robots for different radiation fields. QFS-100 robot is a wheeled remote control robot suitable for strong radiation field. It can replace the personnel to conduct on-site scene exploration, radiation level measurement, sampling, light and small under the conditions of radioactive pollution and unpredictable or high radiation conditions. Emergency operations such as item grabbing. The key parts inside the robot have been treated with radiation resistance and have undergone strict radiation resistance performance tests. The robot is equipped with a radiation-resistant camera and a gamma dose rate measuring device, and can be equipped with other types of radiation measuring devices as needed, and can be controlled through wireless and wired modes.
The BHBot401 (basic type) robot developed by the Atomic Energy Institute replaces personnel with basic operations such as short-range information acquisition and item grabbing and transfer in the event of a nuclear accident, and through flexible selection of end-effectors and professional equipment, the robot also has gas , Liquid sampling and other functions. Equipped with a nuclear radiation detection device, which can provide information on the dose intensity, type of nuclide, and contaminated area of nuclear radiation.
After nearly 30 years of development, China's nuclear emergency technology has formed a relatively complete nuclear emergency technology system. After the Fukushima nuclear accident, China has fully borrowed international experience and improved its nuclear emergency capability by further strengthening its nuclear emergency capability building. With the rapid development of nuclear energy in China, China also needs to strengthen basic research on nuclear emergency technology, integration and verification of emergency assessment systems, emergency information management, protection technology research, and development of special robots. The emergency scientific research capability has reached the international advanced level. At the same time, it is also necessary to strengthen professional training, enhance the capabilities of nuclear emergency personnel, improve the effectiveness of the exercise, establish a nuclear emergency system that is compatible with the scale of nuclear energy development, and ensure the sustainable development of the nuclear industry. (The author is Zhang Jintao, Ministry of Safety and Environmental Protection of China Nuclear Group; Zhang Jiangang, China Academy of Radiation Protection)