Small Modular Reactors (SMRs) are transforming the future of nuclear energy by offering a compact, scalable, and safer alternative to traditional large nuclear plants. With increased emphasis on clean energy and carbon reduction, SMRs are seen as a key technology in the global energy transition. Their smaller size, enhanced safety features, and modular nature allow them to be deployed in a wide range of locations, including remote areas, and provide energy in a more cost-effective and flexible manner. This section highlights the current developments in SMR technology, categorizing reactors into those that are deployed, under construction, and in the design phase.

Deployed SMRs

China's HTR-PM (High-Temperature Gas-cooled Reactor – Pebble Bed Modular)
China’s HTR-PM is one of the first operational Small Modular Reactors in the world. Located at the Shidao Bay Nuclear Power Plant in Shandong province, the HTR-PM uses high-temperature gas-cooled technology with pebble-bed reactor designs, where spherical fuel elements, or "pebbles," are utilized for their robustness and high thermal efficiency. Each reactor in the HTR-PM system generates about 210 MW of electricity, with two reactors working in tandem at the site. China began the testing phase in 2021, and the plant is expected to begin full commercial operations soon. The HTR-PM is seen as a significant step forward in SMR deployment and a key part of China’s strategy to advance nuclear energy technology.

Russia's Akademik Lomonosov (Floating Nuclear Power Plant)
Russia’s Akademik Lomonosov is a floating nuclear power plant, powered by two KLT-40S reactors, each generating 35 MW of electricity, for a total output of 70 MW. The plant is designed to provide power to remote regions where conventional power infrastructure is not feasible, such as island nations or the Arctic. Deployed in 2019, the Akademik Lomonosov began operations in the Arctic town of Pevek . It replaced an aging coal power plant and provides a cleaner, more reliable energy source for the region. While the floating plant is operational, it continues to serve as a prototype, with performance assessments and future plans for further deployment in other remote areas.

Under Construction SMRs

NuScale Power (USA)
NuScale Power , based in the United States, is developing an SMR that is one of the closest to becoming fully operational. The NuScale Power Module (NPM) features a small, pressurized water reactor design capable of generating 60 MW per module. NuScale’s design is highly modular, meaning that multiple units can be combined to scale up power output as needed. In 2020, the U.S. Nuclear Regulatory Commission (NRC) approved the NuScale design, marking the first approval for a small modular reactor in the U.S. Currently, the company is moving forward with plans to build a commercial demonstration plant, known as the Carbon Free Power Project , in Idaho. The plant will consist of 12 NuScale reactors, ultimately producing 720 MW. Construction of the demonstration plant is slated to begin in the coming years, with the first power generation expected by the late 2020s.

Rolls-Royce (UK)
In the United Kingdom, Rolls-Royce is developing its own SMR design with a focus on reducing nuclear power costs and increasing competitiveness with other energy sources. The Rolls-Royce SMR is designed to generate 470 MW of electricity. The project is backed by the UK government, which has provided significant funding through its Nuclear Energy (SMR) Innovation Programme . The first prototype unit is expected to be deployed by the early 2030s, with construction and licensing processes currently underway. The UK government’s investment in Rolls-Royce’s SMR project reflects the country’s commitment to maintaining nuclear power as a part of its energy mix for decarbonization.

SMRs in the Design Phase

TerraPower’s Natrium Reactor (USA)
TerraPower, co-founded by Bill Gates, is developing an advanced modular reactor called the Natrium reactor, which combines a sodium-cooled fast reactor with a molten salt energy storage system. The Natrium reactor is designed to produce 345 MW of electricity and is intended to be deployed in regions requiring flexible, low-carbon power sources. The company received substantial backing from the U.S. government under the Advanced Reactor Demonstration Program (ARDP), and it has partnered with Warren Buffet’s Berkshire Hathaway to fund its development. The Natrium reactor is planned for construction in Wyoming, with deployment expected in the mid-2020s, pending regulatory approval and final design adjustments.

X-Energy's Xe-100 (USA)
Another promising SMR design under development is X-Energy's Xe-100 , a high-temperature gas-cooled reactor (HTGR) that utilizes pebble-bed technology. The Xe-100 reactor is designed to generate 80 MW of electricity per unit, and it is intended to be modular, with plants able to combine multiple units to meet varying energy demands. X-Energy has received funding from the U.S. Department of Energy (DOE) for research and development, and the company has partnered with Bechtel for the design and construction phases. X-Energy aims to build the first commercial Xe-100 reactor by the late 2020s, with the first plant expected to be deployed in the U.S. These reactors are designed to offer enhanced safety features and can be deployed in a range of applications, from powering small communities to supporting industrial activities. Regulatory approval and final design adjustments are ongoing, with a focus on demonstrating the reactor's performance and economic feasibility.

Conclusion

The development and deployment of Small Modular Reactors (SMRs) are rapidly advancing worldwide, with significant progress made in China, Russia, the U.S., and the UK. The HTR-PM and Akademik Lomonosov are examples of SMRs already deployed and operational, serving as important milestones in the evolution of nuclear energy. In the U.S., NuScale Power is leading the way with plans for a commercial demonstration plant, while in the UK, Rolls-Royce is moving forward with a competitive SMR design. Meanwhile, innovative projects like TerraPower’s Natrium and X-Energy’s Xe-100 are progressing through the design phase, with expectations to join the SMR market in the near future. With their scalability, enhanced safety, and reduced environmental footprint, SMRs are poised to play a key role in the global transition to a low-carbon energy future.