Small modular reactors (SMRs) represent a transformative approach to nuclear energy, offering a pathway to decentralized hydrogen production. These reactors, typically with capacities under 300 MWe, are designed for factory fabrication, modular deployment, and flexible integration with industrial processes. Their compact size and inherent safety features make them suitable for supplying both heat and electricity to hydrogen generation systems, particularly in remote or industrial settings where large-scale nuclear plants are impractical.

One of the primary advantages of SMRs is scalability. Unlike traditional gigawatt-scale nuclear reactors, SMRs can be deployed incrementally to match local hydrogen demand. This modularity reduces upfront capital costs, as utilities or industrial operators can add capacity as needed rather than committing to a single, costly mega-project. The standardized design of SMRs also streamlines regulatory approval and construction timelines, further lowering financial barriers. For hydrogen production, this scalability allows nuclear-assisted electrolysis or thermochemical processes to be tailored to regional needs, whether for fueling transportation, supporting industry, or stabilizing renewable-heavy grids.

SMRs excel in providing high-temperature heat, a critical input for efficient hydrogen production. While electrolysis relies on electricity, thermochemical water-splitting methods like the sulfur-iodine cycle require temperatures exceeding 800°C—conditions that conventional light-water reactors cannot achieve. Advanced SMR designs, such as high-temperature gas-cooled reactors (HTGRs) or molten salt reactors, can deliver this heat directly, improving the thermodynamic efficiency of hydrogen generation. Coupling SMRs with solid-oxide electrolysis cells (SOECs) further enhances efficiency, as the reactor’s waste heat can preheat water inputs, reducing electrical demands.

Compared to large-scale nuclear plants, SMR-based hydrogen production offers distinct logistical and economic benefits. Large reactors are often confined to centralized locations due to cooling requirements and grid dependencies, limiting their use for distributed hydrogen networks. SMRs, by contrast, can be sited closer to demand centers, such as steel plants or ammonia factories, minimizing hydrogen transport costs. Additionally, SMRs mitigate transmission losses by co-locating power generation with electrolyzers or chemical plants. For remote regions lacking grid infrastructure, SMRs provide a stable, carbon-free energy source to produce hydrogen for local use or export, bypassing the need for expensive pipeline or shipping networks.

Industrial applications stand to gain significantly from SMR-driven hydrogen. Heavy industries like steelmaking and cement production require continuous, high-energy inputs, which intermittent renewables struggle to supply alone. SMRs can deliver steady heat and power for hydrogen-based direct reduced iron (DRI) processes or replace fossil fuels in high-temperature industrial heating. In the chemical sector, SMRs could decarbonize ammonia and methanol synthesis by providing clean hydrogen feedstock. The ability to integrate with existing industrial zones without extensive grid upgrades makes SMRs a pragmatic solution for deep decarbonization.

Several SMR projects worldwide are pioneering nuclear hydrogen production. In the United States, the Department of Energy supports the Advanced Reactor Demonstration Program, which includes HTGR-SMR designs aimed at hydrogen co-generation. The X-energy Xe-100 reactor, for example, is being developed to supply process heat for industrial hydrogen applications. Canada’s Ontario Power Generation plans to deploy a GE Hitachi BWRX-300 SMR by the late 2020s, with potential off-grid hydrogen production for mining operations. In the United Kingdom, the Rolls-Royce SMR program explores hydrogen as a secondary output alongside electricity. Internationally, China’s HTR-PM high-temperature reactor has demonstrated thermochemical hydrogen production at pilot scale, while Japan’s HTTR research reactor has tested iodine-sulfur cycles.

Safety and regulatory frameworks for SMRs are evolving to accommodate hydrogen integration. Passive safety systems, such as natural convection cooling and underground siting, reduce risks in populated or industrial areas. Licensing efforts now consider combined energy outputs—electricity, heat, and hydrogen—streamlining approvals for multi-product facilities. However, challenges remain, including public acceptance of nuclear-coupled hydrogen systems and the need for standardized codes for reactor-electrolyzer interfaces.

The economic viability of SMR-based hydrogen hinges on production costs relative to alternatives. Current estimates suggest nuclear hydrogen via electrolysis could reach $2–$4 per kilogram at scale, competitive with green hydrogen from renewables in regions with low wind or solar resources. Thermochemical cycles, though less mature, promise further cost reductions by leveraging high-temperature efficiencies. Hybrid systems, where SMRs supplement renewable electrolysis during low-wind or low-sun periods, could optimize costs while ensuring continuous output.

In remote settings, SMRs address energy security and decarbonization simultaneously. Arctic communities, island nations, or off-grid mining operations often rely on diesel generators or LNG imports for power and heat. SMRs paired with hydrogen production could displace these fuels, providing electricity, heating, and hydrogen for local transport or equipment. For export-oriented regions, SMRs enable hydrogen or derivative (e.g., ammonia) production without relying on volatile renewable output, attracting investment in hydrogen hubs.

The future of SMR-driven hydrogen depends on accelerated deployment and cross-sector collaboration. Pilot projects must validate cost and performance data at commercial scales, while governments and industries align on infrastructure investments. As carbon pricing mechanisms expand, the economic case for nuclear hydrogen will strengthen, particularly in sectors where electrification is impractical. With their dual role in clean power and industrial decarbonization, SMRs are poised to become a cornerstone of the emerging hydrogen economy.