The security of advanced reactors

IN RECENT YEARS, THERE HAS been growing interest around advanced reactor designs to deliver carbon-free power for a range of commercial applications that extend beyond simply supplying electricity. Advanced reactors may also address some of the longer-term challenges of nuclear technology, including cost and competitiveness, potential proliferation issues, waste, safety and security.

The World Institute for Nuclear Security (WINS) believes that developing stakeholder confidence is vital for implementing these technologies. It published a Special Report on the Security of Advanced Reactors that drew on more than 20 interviews with developers, regulators and subject matter experts.

The report provides an overview of the international environment in the deployment of advanced reactors, examines the security considerations and challenges of various reactor designs and recommends ‘security by design’ methodologies.

International perspective and regulatory Issues

The Report offers a high-level perspective of the available international instruments, standards and guidance that shape national regulations and laws surrounding advanced reactors.

WINS recognises that the International Atomic Energy Agency (IAEA) is the primary international organisation that provides guidance relevant to developers and it has two key documents on this. The first is the IAEA Nuclear Security Series (NSS) 13, which provides general guidance on physical protection and interfaces with safety and nuclear material accountancy and control activities. The IAEA also provides comprehensive guidance in NSS 35G (Security During the Lifetime of a Nuclear Facility) and suggests incorporating nuclear security in the early design stage and integrating security with safety, safeguards, operational and other measures.

Two international working groups are evaluating the viability of advanced reactors in a number of areas, including physical protection. The first is the International Project on Innovative Nuclear Reactors and Fuel Cycles (INPRO), and the second is the Proliferation Resistance and Physical Protection Working Group.

WINS interviewed officials from three regulatory bodies to understand common challenges in their approach to developing regulations for and licensing these advanced reactors. They are examining a performance-based approach with fewer prescriptions, which recognises that advanced reactors may require a flexible and technology-neutral approach to address significant variations between the different reactor designs. They recognise the importance of emerging technologies and threat capabilities, particularly cybersecurity, a new and evolving threat that will require an update of the regulatory framework.

Security considerations for advanced reactor designs

One of the main objectives of the WINS Special Report is to encourage advanced reactor developers to incorporate ‘security by design’ as early as possible. Developers first have to understand the security considerations for advanced reactor designs. WINS’ research found that the risk of theft or sabotage depends on the quantity of material used and frequency of refuelling, which varies depending on the technical characteristics of the reactor. All these considerations will affect security.

Some designs will be less susceptible to overheating and core damage as they will use passive safety features and be less reliant on external power. Some designers are incorporating engineered physical protection systems into their designs, such as underground siting to defend against potential scenarios such an aircraft crash.

According to WINS’ research, developers see licensing cost as a primary concern. This means that developers can only propose optimisation for security arrangements that does not compromise safety or security. This is made even more challenging as incorporating security features similar to those required by traditional nuclear power plants into the reactor design is not economic, primarily in terms of operation and maintenance costs. Developers interviewed by WINS say that the enhanced safety characteristics of advanced reactors should form the basis for demonstrating risk-informed security requirements.

Developers also say that automation is a significant design goal. Automation in safety and security for will make reactor operations more economical. It may reduce human error and the potential for insider threats significantly. Likewise, the inclusion of robotic technologies like drones can cut costs by reducing the number of security employees. Advanced technologies could improve threat detection.

During its research, WINS was able to map out the following various security challenges:

• High-assay low-enriched uranium (HALEU) and the supply chain. HALEU is enriched between 5% and 20%. Some developers interviewed by WINS are concerned about the differentiation between LEU and HALEU. The description of HALEU has introduced confusion about its categorisation for the purposes of physical protection.
• Remote siting. A significant number of the advanced reactor designs such as the heat pipe reactors are intended to be used at remote locations and offshore. Difficult access to these remote sites can have security advantages and disadvantages. Problems could include cyber or effective response teams.
• Transport. Some reactor designs will include fuel and in some the fuel will be transported separately. It is important for the designer to consider transport during the fuel cycle, including during decommissioning.
• Cybersecurity. The approach taken to address cybersecurity is no different from the existing one. There is nothing particularly unique about advanced reactors from a cyber perspective beyond the potential for remote siting.

Security by design for advanced reactors

Security by design requires that security be integral in the design from the onset. It is a risk-informed approach that requires a clear security strategy and a commitment to make security a primary design consideration on par with nuclear safety. It also requires a coordinated approach by all parties including operators, project managers and regulators.

The key principles of security are to deter, deny, detect and delay. We can add design to these. These principles can reduce the risk of a major security incident. Although initial design costs may be higher, ‘security by design’ will help to reduce the cost of preventing a nuclear security incident, and the savings will accumulate over the life of the advanced reactor.

The steps towards developing a comprehensive approach to ‘security by design’ are:

• Set up your organisation. ‘Security by design’ can only work if your organisation is set up to deliver it. All — from the chief executive down — must view security as an integral part of the organisation.
• Understand the threats and consequences. Understand the threats your advanced reactor facility could face, including unauthorised removal of material and sabotage.
• Establish your design objectives. Based on the possible threats against your facility and the resources you have to manage them.
• Develop your protection model. Many design solutions are available to meet your security objectives. The choice will depend on what you are protecting, their status, the nature of the threat and the resources that are available.

WINS recognises other methodologies exist, but its Special Report recommends three comprehensive methodologies and provides detailed ‘security by design’ guidance to developers. Starting points include: The Security by Design Handbook (Sandia National Laboratories); Secure by Design (a guidance document developed by Adrian Prior and Robert Barnes in the UK); and an Evaluation Methodology (developed by the Gen IV Proliferation Resistance and Physical Protection Working Group). The latter identifies a set of challenges, analyses a system response to these challenges, and assesses outcomes for a proposed design. The characteristics of advanced reactor systems (technical and institutional) are used to evaluate the system’s response and further determine its resistance against threats of proliferation and robustness against sabotage and terrorism threats.

Preparation is key to leverage benefits

Lower costs, less maintenance and easier operations are strong incentives to use advanced reactors in a wide range of environments and geographical locations. Advanced reactors are inherently safer than commercial nuclear power plants in operation, could be located closer to densely populated areas and provide energy at the point of need. Their flexibility means they could play a key role in the emerging decentralised power supply energy market.

As the WINS Report on the Security of Advanced Reactors confirms, their security implications must be identified and addressed as early as possible, as design and technological choices will affect the risk picture and might require changes in the regulatory approach.

Author details: A´lvaro Acevedo is Programme manager at the World Institute for Nuclear Security