Small Modular Reactors

SMRs encompass various technologies, including scaled-down LWRs, gas-cooled reactors, and fast reactors. Their primary innovation is “modularity” – the ability to add units as demand grows. Many SMR designs incorporate passive safety features that rely on natural circulation rather than pumps. Supply chain considerations focus on factory-based manufacturing and the need for standardised components to achieve economies of series. Logistical challenges include transporting the reactor modules to sites with limited access. SMRs are highly attractive for developing countries or smaller markets due to lower upfront capital costs compared to traditional large-scale plants, as well as factors such as their modularity and smaller output which facilitates expansion of capacity as the demand for electricity increases.

The nuclear safety risks associated with SMRs are related to direct exposure to radiation and contamination through the release of radioactive materials into the environment. This can be due to malfunctions or accidents, or the mismanagement of radioactive waste or spent fuel. SMRs have inherent safety features, such as passive decay heat removal and a low probability of core meltdown. Nevertheless, robust safety systems and regulations are essential to minimise these risks.

Stringent security measures are essential to ensure proper control and prevent, detect or respond to theft, sabotage, unauthorized access, illegal transfer or other malicious acts involving the nuclear fuel, other radioactive material or the nuclear facility itself. Modular designs may allow for underground siting, which enhances physical protection against external threats.

The applicable IAEA safeguards agreement will be implemented, involving, for example, inspections, nuclear material accounting, and containment and surveillance measures, to verify the peaceful use of nuclear materials. Sealed reactor cores, long fuel cycles, factory-based manufacturing and transport across international borders, remote locations and novel fuel forms are some of the safeguard challenges for SMRs. “Safeguards by Design”, incorporating built-in sensors and inspection access points into the SMR design, will facilitate the implementation of safeguards during operation.