This paper proposes to design security measures based on the radioactive material package as the basic unit. The principle of four-layer defense in depth is put forward. Based on the concept of self-security intelligence, combined with out-of-vehicle monitoring, in-vehicle monitoring, and Beidou positioning technology, a security system for transport of radioactive materials was designed. It realized the perception, early warning, delay, and alarm functions and greatly improved the security.
The security of radioactive material is an important matter related to the national economy and people's livelihood. Radioactive material in transport is more likely to be lost, stolen, and damaged compared with the fixed place [
According to the D-values that were developed to define a dangerous source [
Since the transport security level is determined according to the package, we believe that it is necessary to decentralize security measures to the package, not just the conveyances of transportation. At the basic security level, the packaging container is equipped with electronic equipment to provide basic detection and alarm functions. At the enhanced security level, it is necessary to add positioning and radioactivity monitoring functions on the basis of detection and alarm functions. As one of the implementation methods, giving the radioactive material “self-security intelligence” [
Radioactive materials are usually placed in specific packaging containers during transport, as shown in Figure
Radioactive material in transport (photo: IAEA).
Most of China’s nuclear power plants are in the eastern coastal areas. However, the intermediate test plants for spent fuel pool and power reactor spent fuel reprocessing are located in the western region [
The distance between the posttreatment site of nuclear material and nuclear power plant is thousands of kilometers. Transport may span different provinces and cities. The climate conditions and landform along the transport route are different. The road conditions are complex. The probability of accidents in transport is high.
The spent fuel can be stored away from the reactor after being temporarily stored in the reactor pool for 5 years, but the actual time is uncertain. In addition, considering the economic cost, most nuclear power plants even extend the storage time in the pool. For these reasons, the amount of radioactive materials transported at one time is uncertain, so the number of transport vehicles is not fixed.
Response forces include on-board security personnel and local police. The on-board security personnel can respond to the loss and theft of radioactive material in transit. The on-board security personnel and the local police cooperate to respond to the threat of robbery of radioactive material. Generally, a transport vehicle is equipped with on-board security personnel [
To protect radioactive materials (including nuclear materials) from theft and destruction during transportation, it is necessary to evaluate the nature, possibility, and risk consequences of potential nuclear material transportation events. Then, identify all possible threats based on the collected information, classify them according to the degree of threat, and analyze the physical protection level of nuclear materials [ While the transport vehicle is parked or running, an adversary suddenly approaches the vehicle, uses a cable-pulling gun and a rope tool to climb onto the vehicle and open the door, or uses a tool to break the vehicle from a nondoor. The adversary opened the door in a manner that did not attract the attention of security personnel (such as individual insider colluding with the adversary) and entered the compartment to plan to steal or destroy the radioactive material container. The adversary opened the door in a way that did not attract the attention of the escort personnel and illegally approached the radioactive material and transferred it outside the vehicle. Another possibility is that the radioactive material has been lost on its own. It is assumed that the container was not damaged during the transfer.
With reference to the physical protection of nuclear power plant, the vehicle transport security system also has control area, protect area, and vital area. The control area refers to the long distance outside the vehicle in transport and the temporary park area. Protect area refers to the area near the vehicles. The vital area refers to the space inside the compartment.
In response to the aforementioned threats, it is proposed to provide long-distance monitoring outside the vehicle, close-distance monitoring outside the vehicle, monitoring inside the vehicle, and self-security intelligence of radioactive material four-level defense in depth in transport, as shown in Figure
Depth defense for vehicle transport security system.
Balanced protection means that no matter how an adversary attempts to accomplish the goal, effective elements of the security system will be encountered. During normal driving, the vehicles are usually arranged in straight or curved lines, rarely side by side. In response to this situation, the detection of the side of the body of a single vehicle needs to be strengthened, so do the head and tail vehicles. If a vehicle in the middle of the fleet detects a threat, the security people in other vehicles can quickly respond. However, if the head or tail vehicle is threatened, the security response time of the other vehicle of the fleet will be longer. Therefore, it is necessary to increase the number of security personnel on the head and tail vehicles.
The security system of the transport fleet is shown in Figure
Vehicle fleet transport system.
The security system of a single vehicle is composed of the subsystems such as detection outside the vehicle, detection inside the vehicle, self-security intelligence, host, portable device, and communication, as shown in Figure
Single-vehicle security system in transport.
In response to threat (1), it is proposed to install monitoring sensors outside the vehicle, including passive infrared detection, microwave detection, video monitoring, and Beidou positioning, as shown in Figure
Monitoring configuration outside of the vehicle.
In response to threat (2), it is proposed to install monitoring sensors in the vehicle (as shown in Figure
Monitoring configuration inside of the vehicle.
In response to threats (2 and 3), it is proposed to install an electronic device on the radioactive material container to realize self-security. The device implements passive infrared detection, the long-range RFID, Zigbee communication for group defense, video forensic, Beidou positioning, and other functions, as shown in Figure
Self-security intelligence system of radioactive material.
The information security of radioactive material transportation implements a hierarchical confidentiality plan. The transportation leading group formulates a physical protection plan and informs the carrier and the transportation team of the time, location, route, and transportation schedule before departure. The vehicle transport security system cannot be closed during transportation. Two or more communication methods are provided between the transportation fleet and the emergency response force, and the confidentiality measures for communication are stipulated. The wireless signal transmitted by the communication system needs to be encrypted. The communication between the host computer and the portable terminal, especially, adopts multiple frequency bands, and frequency hopping communication can be used when necessary to improve safety and reliability. The self-security device sends the image and positioning information to the command center via the 4G network only regularly after you leave the transportation vehicle and the group. In order to guarantee information security, the 4G network is encrypted.
The radioactive material transportation security system designed in this paper is an integrated security system from outside to inside. No matter whether the transportation vehicle is in operation or temporarily staying, it can effectively detect the adversary’s attack on the transportation vehicle, entering the transportation vehicle, and even stealing radioactive material. The entire monitoring process is real-time and continuous, so the receiver can be more confident that the radioactive material has not been disassembled or stolen during transportation. Since the carrier cannot close the security system after the transportation starts, it is effective to the internal threat for the carrier's participation. When a single radioactive material container is stolen or lost, it can be discovered in time for easy retrieval because the container is equipped with a positioning function.
This article analyzes the relevant regulations for the transportation of radioactive materials, proposes to design security measures based on the radioactive material package as the basic unit, and then designs a complete set of security monitoring systems for the transportation of radioactive materials on this basis. Take China’s radioactive material transportation as an example, this paper analyzes the characteristics of vehicle transport of radioactive material and proposes design principles such as possible threat scenarios and four-layer defense. Based on the concept of self-security intelligence, combined with out-of-vehicle monitoring, in-vehicle monitoring, and Beidou positioning technology, a security system for transport of radioactive materials was designed. It can detect the illegal approaching vehicle and radioactive material and identify the illegal movement of radioactive material.
The data used to support the findings of this study are included within the article.
The authors declared that there are no conflicts of interest regarding this publication.
This paper was funded by China’s National Defense Science and Technology Innovation Special Zone Project “A New Method for Predicting Nuclear Accidents Based on Causality Model (project no. 18-163-15-LZ-001-002-09).”