Small Modular Nuclear Reactors: The Future of Clean Energy

Small modular nuclear reactors (SMRs) are advanced nuclear reactors with a power capacity of up to 300 megawatts electric (MWe) per unit, roughly one-third the size of conventional nuclear reactors. Unlike traditional plants, which are often custom-built and exceed 1,000 MWe, SMRs are designed for modular construction. This means they’re manufactured in factories as standardized units, then shipped and assembled on-site, reducing construction time and costs. Their smaller size allows them to fit in locations unsuitable for larger plants, such as remote areas or industrial sites.

SMRs use nuclear fission to generate heat, which produces steam to drive turbines for electricity. They come in various designs, including pressurized water reactors (PWRs), the most common type, and advanced models using coolants like helium, molten salt, or liquid metal. These designs enhance safety and efficiency, making SMRs a versatile option for power generation, industrial heat, desalination, or even hydrogen production. International Atomic Energy Agency (IAEA) defines SMRs as a key technology for sustainable energy.

Recent Advancements in SMR Technology

The development of SMRs has gained momentum globally, driven by the need for low-carbon energy and energy security. Here are some key advancements as of 2025:

• NuScale’s Breakthrough: NuScale Power Corporation, based in Oregon, became the first company to receive U.S. Nuclear Regulatory Commission (NRC) approval for its 77 MWe SMR design in 2022. Their NuScale Power Module (NPM) features passive safety systems, like a gravity-driven boron dilution system, which ensures safe shutdown without external power. NuScale is partnering with Romania for a six-module plant, aiming for operation by the early 2030s. NuScale Power

• GE Hitachi’s BWRX-300: This 300 MWe boiling-water reactor, selected by Ontario Power Generation, is set to debut in Canada by 2029. It uses existing U.S.-approved fuel, simplifying supply chains. Poland plans to deploy 24 BWRX-300 units, signaling strong international interest. GE Hitachi Nuclear Energy

• China’s Progress: In 2023, China commissioned the 210 MWe Shidaowan high-temperature gas-cooled reactor (HTGR), a milestone for advanced SMRs. The Linglong One (ACP100), a 125 MWe reactor for power, heating, and desalination, is expected to start in 2026. World Nuclear Association

• Holtec’s SMR-300: Holtec International’s design, approved by the NRC, integrates gravity-driven water and air-cooling systems for enhanced safety. Holtec plans to deploy SMRs at the decommissioned Oyster Creek site in New Jersey and is exploring projects in Pennsylvania and Ohio.

• Global Initiatives: The IAEA reports over 80 SMR designs in development, with three operational in China, Russia, and Japan. The European Commission launched the European SMR Industrial Alliance in February 2024 to accelerate deployment by 2030, focusing on safety and supply chain development. European Commission

• Tech Giants’ Interest: Companies like Amazon, Google, and Microsoft are investing in SMRs to power data centers for AI and cloud computing. For example, Google partnered with Kairos Power for 500 MW of SMR capacity, highlighting the technology’s role in meeting high energy demands.

These advancements show SMRs moving from concept to reality, with countries like the U.S., China, and the UK leading the charge. World Economic Forum emphasizes their potential for standardized, mass-manufactured production.

Benefits of SMRs

SMRs offer several advantages that make them attractive for the energy transition:

• Smaller Footprint: Their compact size allows deployment in remote areas, industrial sites, or regions with limited water access, unlike large reactors that require significant cooling water.

• Cost Efficiency: Factory assembly reduces construction costs and time compared to custom-built large reactors. Economies of scale from serial production further lower costs.

• Enhanced Safety: Many SMRs use passive safety systems, relying on natural phenomena like gravity and convection for cooling, eliminating the need for external power or human intervention during emergencies.

• Flexibility: SMRs can be incrementally added to meet growing energy demands, making them ideal for replacing coal plants or supporting hybrid systems with renewables.

• Low-Carbon Energy: SMRs produce minimal greenhouse gas emissions, supporting climate goals. They can also provide heat for industrial processes, reducing reliance on fossil fuels.

• Reduced Fuel Needs: SMRs require less frequent refueling, typically every 3-7 years, compared to 1-2 years for traditional reactors. Some designs can operate for up to 30 years without refueling.

These benefits position SMRs as a critical tool for decarbonization, especially in regions seeking energy independence after events like Russia’s invasion of Ukraine.

Challenges Facing SMRs

Despite their promise, SMRs face hurdles that must be addressed for widespread adoption:

• High Initial Costs: First-of-a-kind projects are expensive. For example, NuScale’s Idaho project was canceled in 2023 after costs rose from $5 billion to $9 billion due to inflation and high interest rates.

• Regulatory Barriers: Licensing processes vary globally, and standardizing approvals for diverse SMR designs is complex. The U.S. ADVANCE Act (2024) aims to streamline microreactor licensing, but progress is slow.

• Fuel Supply: Many SMRs require high-assay low-enriched uranium (HALEU), which lacks a robust domestic supply chain in the U.S. Urenco USA is developing HALEU production in New Mexico, but scaling up takes time.

• Public Perception: Nuclear energy faces skepticism due to past disasters like Chernobyl and Fukushima. Educating communities about SMRs’ safety features is crucial for acceptance.

• Waste Management: While SMRs produce less waste than large reactors, radioactive waste storage remains a concern. Advanced designs using recycled fuels could mitigate this issue.

Addressing these challenges requires coordinated efforts between governments, industry, and regulators to build trust and infrastructure.

The Role of SMRs in the Energy Transition

SMRs are poised to play a pivotal role in achieving global net-zero goals. The International Energy Agency predicts nuclear power will reach an all-time high in 2025, with SMRs contributing to this growth by 2030. Their ability to provide reliable, dispatchable power complements variable renewables like wind and solar, ensuring grid stability.

In regions like Africa, SMRs are gaining traction to support economic development. Rwanda and South Africa are advancing SMR projects to reduce fossil fuel dependence. In the U.S., the Department of Energy’s $900 million investment in SMRs aims for deployment by the 2030s, with projects like the BWRX-300 at Tennessee Valley Authority sites.

SMRs also offer unique applications, such as powering data centers, military bases, or maritime vessels. Russia’s Akademik Lomonosov, the world’s first floating SMR, delivers power to remote areas, showcasing their versatility.

Looking Ahead

Small modular nuclear reactors represent a transformative step toward a cleaner, more flexible energy future. With advancements in safety, cost efficiency, and scalability, SMRs are moving closer to commercial reality. However, overcoming regulatory, financial, and public perception challenges is critical to their success.

As countries like the U.S., China, and the UK push for deployment by the early 2030s, SMRs could redefine how we power our world. By integrating with renewables and supporting diverse applications, they offer a path to sustainable energy that balances reliability and environmental goals. Keep an eye on this space—SMRs may soon be at the heart of the global energy transition.