Proliferation Risks Associated with Small Modular Reactors |
Advanced nuclear technologies are members of a larger class of innovative low- and zero-emissions energy technologies intended to expand access to low-cost, resilient, and sustainable electricity generation across diverse environments and communities. Among these technologies are tidal energy turbines, vertical axis wind turbines, green hydrogen plants, microreactors, and small modular reactors (SMRs). In an era of global supply chain disruptions, trade wars, and surging energy demand, SMRs are uniquely positioned to offer a climate-friendly solution in many regions, particularly those that would still be considered developing. The technical and operational design of SMRs makes nuclear energy more accessible and allows for a shift to an emissions-abating baseline load, regardless of demand or location. However, these modularized reactors are not without their drawbacks.
The drawbacks discussed are relevant to other advanced nuclear technologies, such as microreactors, which have power ratings of 10 MWe or less. However, this paper focuses exclusively on proliferation risks related to SMRs, as they are not only the most commercially viable advanced nuclear technology, but they will also be the most immediately relevant in global non-proliferation discourse.
The Novelty of Small Modular Reactors
SMRs offer greater accessibility, as well as financial and geographic flexibility, to host nations relative to conventional commercial nuclear reactors. However, current frameworks and industry standards were designed for an industry focused on a limited quantity of large-scale reactors, distributed across technologically and institutionally advanced nations, with a specific range of fuel types and lifecycles. As a result, these standards risk inadequacy for managing emerging SMR proliferation risks and are often perceived by operators as overburdensome and unnecessary.
Alongside these concerns in the fast-evolving nuclear power industry are the nations that dominate the sector. China and Russia are the primary suppliers of SMRs and microreactors, and they have become increasingly at odds with international institutions in recent years. Therefore, it is critical that the international community actively revises and implements additional safeguards to uphold non-proliferation measures in an era of advanced nuclear technologies. While the safeguards-by-design framework generally addresses many of the technical concerns associated with the proliferation of fuel from advanced nuclear technologies, the broadened international scope of SMR deployment challenges the effectiveness of these measures and introduces additional proliferation risks.
Small Modular Reactors
Small modular reactors are generally defined as nuclear reactors with a power rating of less than 300 MWe, yet too large to be considered microreactors. Their modularized design theoretically allows for the mass rapid production of the reactor and facility components, enabling standardized safety procedures while reducing the likelihood of catastrophic construction flaws. These components can then be assembled at the new facility’s site (Carelli, 2015). SMRs are not particularly unique in their power rating, given that small and mobile reactors were among the earliest nuclear facilities. However, their modularity, along with SMRs’ focus on mitigating the prohibitive financial uncertainty associated with conventional commercial nuclear reactors, makes them novel community-scale energy solutions.
Modularization is also inherently conducive to faster construction times with the mass manufacturing of reactor assemblies (Christoph et al., 2023). The infrastructure-agnostic operability of SMRs, given the relative output of these reactors and their utilization of passive safety and cooling systems, has allowed industry leaders to quell further global sentiments of “Not In My Back Yard”ism (NIMBYism). With lower decay heat and higher surface-to-volume ratio relative to conventional reactors, process heat can be more readily removed through the use of passive-air cooling systems, making the abundance of effective passive cooling options a competitive advantage for these reactors. Addressing NIMBY concerns is critical, as the community-scale applicability of SMRs will enable their expansion into more remote regions.
As of 2021, seven countries had designs for SMR facilities currently under exploration or development, with Russia and China leading in the construction of terrestrial power-producing and mobile marine propulsion reactors (Popov, 2021). The United States also planned to deploy a demonstration reactor by 2025, but those plans have since been cancelled due to cost overruns anticipated from the first reactor. A second reactor has recently been approved by the US Nuclear Regulatory Commission (NRC) and may soon be under construction, should the US Department of Energy’s (DOE) financing of the reactor remain uninterrupted (Department of Energy, 2025; Carelli, 2015). By 2035, the market potential for SMRs is estimated at around $500 billion at the current pace of global development, with the potential to install around 75 GW of capacity over the next decade. These estimates hinge on a sufficiently diffuse distribution of deployment over the next decade so that the maturity of the ancillary industries can facilitate a low enough levelized cost of electricity to make SMRs cost-competitive (Christoph et al., 2023).
Design-Specific Proliferation Risks
Much of the design-related risk of nuclear proliferation from SMRs stems from the use of higher-enriched uranium compared to that in pressurized light water and CANada Deuterium Uranium (CANDU) reactors. The more common use of high-assay uranium, ranging in enrichment from 5% to 20% U-235, makes the fuel, both fresh and spent, more enticing to clandestine actors with malicious intent to divert it (Virgili, 2020).
Sealed reactor cores are often regarded as a design safeguard against nuclear proliferation as they ensure that the fuel is not tampered with between leaving the manufacturing site and inspection. However, academics caution that sealed reactor cores and the long-term autonomous operability of reactors create monitoring conditions that undermine existing verification and inspection safeguards, placing excessive trust in manufacturers to guarantee the security of their fabrication process. For instance, this presealing prevents the various in-field inspections that host nations........