Making nuclear power plants secure by design

A NEW WAVE OF ADVANCED reactors has the potential to bolster the nuclear renaissance as stricter greenhouse gas emission targets have renewed interest in the nuclear industry. This new generation of reactors, particularly the non-light water reactor design, marks one of the biggest changes in the nuclear industry since the 1950s. With it comes the opportunity and necessity to address nuclear security in a fundamentally different way than predecessor reactor designs, to ensure that they are fit for modern-day threats that continue to evolve and to reduce the reliance on external physical protection measures.

Early reactors

The mid-20th century was an exciting time for nuclear technology after Enrico Fermi led the experiment that allowed the first human-made nuclear chain reaction in the Chicago Pile-1 reactor. The world’s first nuclear power station to supply electricity for domestic use was developed in 1954 at the Obninsk Nuclear Power Plant, which was located at the Institute of Physics and Power Engineering in Obninsk, Russia, about 110 kilometres southwest of Moscow.

While key attributes (safety, security and non- proliferation, cost-effectiveness, grid suitability, etc.) have significantly improved over the past 50 years, the technology to generate and control the thermal energy at the core of the reactor has essentially remained the same. The majority of nuclear electricity is now produced using two reactor technologies that were developed in the 1950s and improved through several generations of reactors. That means that around 85% of nuclear power plants currently in commercial operation are pressurised water reactors or boiling water reactors, which are both types of light water reactors (LWR). Moreover, current nuclear installations are ageing, and their average age exceeded 30 years for the first time in 2020.

21st century developments

After several decades without significant revisions to reactor technology, nuclear industry stakeholders have combined efforts to develop and deploy advanced nuclear reactors because of their importance to sustainability, reliability and long-term energy security. These designs include thermal and fast neutron spectra cores as well as closed and open fuel cycles for commercial use. Unlike conventional LWRs, the new reactors range in size and power, but the majority are much smaller than conventional reactors.

This means that advanced reactors have a much wider potential market and can contribute to desalination, district heating, regional energy parks and other industrial processes. They could also be located closer to densely populated areas and provide energy where the demand exists and reduce transmission losses which can be significant for some supply grids.

A priori, if advanced reactors are to be successful in these diverse markets, they need to be able to offer distinct advantages over other low-carbon electricity sources, including cost effectiveness, reliability, inherent safety, resilience and security. Addressing all of these changes will require innovations in both the technology and regulatory policy.

Incorporating passive safety and effective security

The evidence to date is that the various stakeholders (developers, regulators, operators, etc) have made important progress towards achieving enhanced and passive safety systems, and the commercial and economic indicators look encouraging.

International organisations such as the International Atomic Energy Agency (IAEA), the World Association of Nuclear Operators (WANO), the US Institute of Nuclear Power Operations (INPO), the Electric Power Research Institute (EPRI), the World Nuclear Association (WNA) and the OECD Nuclear Energy Agency (NEA) have published important advice for the nuclear community. The Generation IV International Forum (GIF) is contributing to a better understanding of advanced nuclear energy systems. With 14 member countries, GIF provides a framework to collaborate on research and development of reactor, energy conversion and fuel cycle technologies.

Despite these efforts and contributions, guidance on security matters at the design and pre-construction phases is severely lacking. In common with the existing reactor designs, security is still marginalised, and the risk is that it will remain an afterthought unless the stakeholder community pays adequate attention to the issue. Some parts of the community really understand this and are encouraging much greater engagement and, in that regard, Canada is leading the way.

With support from Canada and other important stakeholders, the World Institute for Nuclear Security (WINS) is working with developers, technologists and regulators to encourage them to collaborate and share their know-how on security matters. Last year, more than 100 international subject matter experts attended two international workshops organised by WINS. These were held in Vienna, Austria, and Ottawa, Canada, and focused on best security practices and new solutions relating to the design, commissioning, and operation of these new reactors (both workshop reports can be downloaded for free by members on www.wins.org). Topics addressed during the events included:

• SMR technologies and their impact on security;
• The impact of SMRs on the regulatory framework, including challenges, opportunities and possible solutions;
• Effective security by design: Interfaces between nuclear safety, safeguards and security;
• Cybersecurity challenges;
• Security issues in the supply chain and fuel manufacturing facilities; and
• Successful engagement with stakeholders on SMR security.

WINS will be publishing a Special Report on the Security of Advanced Reactors, supported by the Nuclear Threat Initiative (NTI), in the second half of 2020. This report will encapsulate the research and findings at that time.

We anticipate that the report will highlight the need for security to be addressed as early as possible in the design process and integrated with safety systems. In addition, effective security by design will require multi-disciplinary teams of technologists, engineers and security experts to address the challenge of implementing security by design during the siting, design, construction, operation and decommissioning of advanced nuclear reactors. It implies adopting an integrated approach from the start that ensures an inherently secure design, passive security (to the extent possible) and adequate resilience to evolving threats.

These attributes are easy to set out but will require a fundamental shift in the attitude towards security, both by designers and technologists and the security community. Working out how to do this — to share design basis threat information, develop common vocabularies and definitions and agree a common approach to safety and security — will be challenging. However, there is evidence that the commitment exists to achieve it.

In addition, the nuclear regulators need to be fully engaged and think about the objectives of security from an outcome-based perspective: Just as with safety, what are the security criteria in terms of potential radiological impact and consequences? This is what matters, and all other aspects of security can be compared to conventional rather than nuclear safety, eg information security, classifications, etc.

A new consideration — for some organisations at least — will be the need to communicate to stakeholders, including civil society and local populations, why they can have confidence in the security (and safety) arrangements, especially if the reactors are to be located close to population centres. The security community will need to take a new approach and develop their ability to communicate clearly and convincingly to stakeholders, after decades of saying, “We don’t discuss security.”

The nuclear industry has an exemplary security record worldwide, but the security threats continue to evolve, as do energy markets and nuclear technology. But as Rafael Grossi, the new Director General of the IAEA, recently said, “It is vital that we remain ahead of the curve in guarding against nuclear terrorism.”

At WINS we are committed to supporting these international efforts to help ensure that the new generation of advanced reactors is secured by demonstrably competent professionals applying best practice to achieve operational excellence.

Author information: Roger Howsley, Executive director, World Institute for Nuclear Security; A´lvaro Acevedo, Project manager, World Institute for Nuclear Security

Image: WINS has organised workshops to discuss security practices for advanced reactors