Small Modular Reactors: Balancing Innovation with Responsibility

To meet climate, energy security and sustainable development goals, policymakers across the world are looking to nuclear energy as an essential player in the energy transition. Nuclear energy is the largest source of carbon-free energy and it has the highest capacity factor of any other source. Since 2023, 31 countries have pledged to triple nuclear energy by 2050. At the 2024 Nuclear Energy Summit, more than 30 world leaders  declared their commitment to unlocking the potential of nuclear power. In the US, nuclear energy has gained support on both sides of the political aisle. Before leaving office, the Biden administration released a 37-page roadmap for increasing US nuclear capacity to 300GW. Shortly after his inauguration, President Trump signed an executive order intended to ‘unleash’ American energy, with ‘particular attention’ on nuclear energy resources, among others. 

Despite positive signaling, an expansion of nuclear power at the pace and capacity needed to address climate change is no sure thing.

The bulk of the 400+ plants in operation around the world today are considered Generation II. These large, conventional reactors, along with Generation III/III+, are multi-billion-dollar infrastructure projects with significant barriers to entry. High capital costs, regulatory and licensing hurdles, long lead times, construction delays and public perception issues affect nuclear plant deployment in states looking to nuclear energy for the first time, as well as those with established programmes. 

These challenges are leading policymakers and industry alike to look toward advanced nuclear technology, specifically small modular reactors (SMRs), as a cost-effective and more easily deployable way to increase nuclear power generation.

As the name suggests, an SMR is small, generating less than 300MW electric, and modular. Most reactor components can be factory fabricated and then transported and assembled onsite. A few companies are working on even smaller microreactors, which will be compact enough to be transported by road, rail or sea and may be able to operate without refueling for 10 years or more. As such, these reactors could provide heat and power to isolated locations or areas affected by natural disasters. Some SMR designs are ‘evolutionary’ and function similarly to conventional large, water-cooled reactors. Others are considered ‘revolutionary’, using new materials and systems.

Compared to their larger counterparts, SMRs offer several potential advantages. New coolants and fuel types, such as liquid metals, gases and molten salts, may offer safety advantages such as higher heat capacities and higher retention of radioactive material. In general, smaller quantities of nuclear material will be needed onsite, and refueling may be required less frequently. 

SMRs employ ‘passive’ safety and security systems. These reactors have the ability to self-regulate and provide sufficient cooling in the event of an electrical outage; by contrast, conventional ‘active’ systems require human intervention. 

Proponents also argue that factory fabrication, simpler design and smaller overall size will result in a reduction of capital and operational costs. Construction and deployment times would be shorter as well. 

Ideally, these advantages will help SMRs overcome some of the largest barriers faced by conventional plants, and will encourage their use in new locations and for new use cases. SMRs could be deployed in countries with smaller electric grids or those without existing nuclear infrastructure. They could be used to provide electricity in remote locations such as military bases, nearer to urban populations, and on transportable or floating power plants. Other services, such as seawater desalination, hydrogen production and district heating could benefit from nuclear energy provided by SMRs. 

A robust framework of international treaties governs nuclear safety, security and liability, forming the backbone of global nuclear governance. These agreements set critical standards for nuclear energy operations, emergency preparedness and materials management. 

• Safety and security: The Convention on Nuclear Safety (CNS) and the Convention on the Physical Protection of Nuclear Material (CPPNM) establish best practices for reactor operations and safeguard nuclear materials against theft and sabotage. 
   
• Accident response: Agreements such as the Convention on Early Notification of a Nuclear Accident and the Convention on Assistance in the Case of a Nuclear Accident or Radiological Emergency coordinate international responses to nuclear accidents. 
   
• Liability and compensation: Several mechanisms, like the Paris Convention on Third Party Liability in the Field of Nuclear Energy and the Vienna Convention on Civil Liability for Nuclear Damage, outline frameworks for compensating victims and assigning responsibility in the case of an incident. 

These agreements were crafted to manage the risks of traditional, large-scale nuclear reactors, and they have served the global nuclear community well. However, the emergence of SMRs introduces new challenges that these frameworks were not designed to address.

SMRs, with their smaller size, modular designs and potential deployment in unconventional locations, expose several limitations in the existing framework. For instance, the CNS explicitly applies only to land-based reactors, leaving floating reactors, like Russia’s Akademik Lomonosov, outside its scope. This gap also extends to new use cases such as transportable SMRs designed for desalination or industrial processes, which may fall into regulatory grey areas.

Another issue arises with liability. Current treaties depend on the location of an accident to determine responsibility. This can become highly complex when considering reactors deployed in international waters or contested territories like the South China Sea, where legal jurisdictions are unclear.

Military applications of SMRs introduce further complications. Treaties governing safety and liability generally exclude military nuclear operations, leaving civilian populations near military bases, such as Eielson Air Force Base in Alaska, vulnerable to potential risks without sufficient legal protections.

As SMRs redefine what is possible in nuclear energy, they also require a rethinking of the rules that govern them. The international community must expand existing treaties to account for new reactor types and deployment scenarios, ensuring comprehensive coverage for both safety and liability. Without these updates, the very innovations that make SMRs so promising could outpace the mechanisms designed to regulate them.

By addressing these gaps proactively, countries can create a governance framework that balances innovation with safety, enabling SMRs to reach their full potential while protecting communities and the environment.