Repurposing former coal power plant sites can reduce the upfront investment needed for nuclear infrastructure, but challenges remain regarding site suitability, economic viability, and regulatory frameworks.
On March 4, 2026, after nearly 18 months of review, the U.S. Nuclear Regulatory Commission (NRC) issued a construction permit for TerraPower's Unit 1 at the Kemmerer site in Wyoming. This marks the first approval for a new commercial nuclear reactor in the United States in nearly a decade, serving as a flagship project in the nation's nuclear energy revival. The U.S. Department of Energy will cover half of its total $4 billion cost.
This power station has several unique features. Its founder is Bill Gates, the reactor employs sodium-cooled fast reactor technology with a 345-megawatt capacity, and it is equipped with a molten salt energy storage system, allowing the system's output to reach up to 500 megawatts. Furthermore, it utilizes the site of a nearby coal-fired power station, the Naughton plant, which is slated for retirement. That plant has three coal-fired units, one of which has already been converted to natural gas.
This site represents a co-location of new nuclear construction with an existing coal power facility. TerraPower chose this location to reuse the existing infrastructure and workforce from the coal plant. Within the industry, the concept of converting retired coal plants to nuclear facilities, known as "coal-to-nuclear" (C2N), has been the subject of considerable research and discussion.
At a basic level, C2N allows for the reuse of a coal plant's site resources and some equipment, lowering the cost of developing a new nuclear site and transforming a high-emission facility into a clean, low-carbon one.
Compared to wind and solar power, converting a similarly sized site to nuclear can deliver significantly greater installed capacity. Over its full lifecycle, nuclear power's carbon emissions are less than one percent of coal's and about one-tenth of wind and solar's. This process also helps preserve local employment, tax revenue, and industrial foundations. In theory, C2N represents a potential pathway for the low-carbon transition of coal power, though its technical feasibility and economic competitiveness require further study and validation.
Research into C2N is currently most advanced in the United States. In September 2022, the U.S. Department of Energy, in collaboration with several national laboratories, published a report titled "Benefits and Challenges of Retrofitting Coal Power Plants with Nuclear Power," identifying 157 retired and 237 operational coal plant sites as potential candidates for C2N conversion.
At the 2026 Spring Conference on Sustainable Nuclear Development, former chairman of State Power Investment Corporation (SPIC), Wang Binghua, suggested that the national level should focus on and support in-depth research and feasibility studies into converting retired coal plants to nuclear energy. He encouraged the energy sector to conduct site analysis and selection and to lead the exploration of establishing processes, evaluation standards, and supportive policies for such conversions. He also recommended that coal and nuclear power enterprises collaborate on in-depth feasibility studies for retired coal plant sites and initiate demonstration projects when appropriate.
How would a 'coal-to-nuclear' conversion work?
The core logic of C2N is to replace the coal-fired boiler, the energy source in a coal plant, with a nuclear reactor on the original site, while reusing existing site infrastructure, equipment, facilities, and grid connections.
Coal plants generate electricity by burning coal in a boiler to heat water, creating steam that drives a turbine. They may also supply steam to industrial parks or district heating systems. In a C2N conversion, facilities like the coal-fired boiler, coal handling systems, and ash disposal cannot be reused and must be replaced by the nuclear reactor and its heat exchange systems. However, many other facilities could be repurposed, including the site land, grid connection infrastructure, office buildings, roads, cooling water sources, cooling towers, and conventional island equipment like turbines and generators, potentially after assessment and modification.
Wang Binghua stated that a major advantage of converting coal plant sites to nuclear projects is the ability to utilize existing infrastructure, saving on land resources and capital costs. Preliminary analysis suggests using a coal plant's infrastructure could save about 10% of the investment. Further savings of 18% to 21% could be achieved by reusing conventional island equipment (the power generation equipment not directly involved with the nuclear reactor and radioactive systems).
According to research published in the journal Southern Energy Construction by researchers including Li Xiaoyu from China Power Engineering Consulting Group, although the working fluid parameters and related equipment differ significantly, the overall architecture and principles of the conventional island are similar, sharing many commonalities in design, construction, and operation. For future C2N projects in China, the main workload would lie in the retrofit of the main power generation equipment.
However, reusing equipment is not straightforward.
At a summit held in Beijing this April by Repower, an NGO focused on sustainable technology for coal power transition, Professor Zhou Sheng's research team from Tsinghua University's Institute of Energy Economics, who have studied the topic for two years, presented their findings. Professor Zhou explained that through a systematic comparison of the thermal systems, steam systems, and safety standards of coal and nuclear power units, they concluded there are very large differences in technical parameters and safety standards. All related coal power facilities and equipment would require varying degrees of modification before reuse, making direct utilization very difficult.
For nuclear power to replace coal's role in China's power and energy system, its ability to provide continuous baseload generation is one aspect. Coal power also plays a role in providing flexible peak-shaving for the grid and supplying heat for the energy system.
Regarding peak-shaving, coal plants adjust their output by directly controlling fuel input and boiler output. For mainstream pressurized water reactor (PWR) nuclear technology, changes in reactor power lead to changes in the physical state of the reactor core, making it less suitable for frequent load-following.
At the Repower summit, some experts proposed that a "reactor + thermal storage + turbine" configuration could be one solution. The reactor provides a stable heat source, a medium like molten salt stores heat during low demand, and releases it to generate power or steam during peak demand. This approach could save about 30% in overnight capital costs (the construction cost excluding interest during construction, financing costs, inflation, and delays) while fulfilling peak-shaving and heat/power supply roles.
The aforementioned TerraPower project at a retired coal plant site in the U.S. includes a molten salt energy storage system.
Regarding heat supply, analysis presented at the conference indicated that China currently has approximately 13-14 billion square meters of non-clean heating area. To meet carbon neutrality goals, about 80% of this needs to be replaced. The future steam demand from China's seven major chemical industrial parks is estimated to reach about 135,000 tons per hour. Replacing just 30% of that would require over 10 gigawatts of nuclear power capacity for heat supply.
Professor Zhou Sheng stated that if a C2N pathway is adopted, by 2060, nuclear power's share of electricity generation could reach 15% to 20%, and its share in heat supply could also reach about 20%. Nuclear installed capacity would increase by 20% to 30%. From a system-wide benefit perspective, C2N could potentially save the power and heating systems approximately 2 to 4 trillion yuan in costs and cumulatively reduce carbon dioxide emissions by 700 million to 2.2 billion tons.
What challenges does 'coal-to-nuclear' conversion face?
To implement C2N, the first issue to address is site suitability.
China's existing nuclear power projects and foreseeable new additions are still largely concentrated along the coast, with inland nuclear power not yet truly realized. However, a large number of coal plants are located inland, close to cities or industrial load centers. Factors such as population density, seismic conditions, and emergency planning zones all affect whether a nuclear project can be sited there.
Nuclear plant site selection typically considers geological conditions, cooling water sources, surrounding population density, and distance from national borders, among other factors. Wang Binghua noted that regarding site feasibility, population and geological conditions are the factors most likely to be disqualifying.
Professor Zhou Sheng's team conducted a screening analysis of over 6,000 coal-fired units nationwide. The results showed that if small modular reactors (SMRs) were used to replace coal units, about 2,400 units across the country could meet the relevant requirements, with a total potential capacity of about 700 gigawatts. However, if the safety standards and site selection requirements for large reactors were applied, the total potential capacity would be about 56 gigawatts, indicating relatively limited potential.
Wang Binghua explained that the China Nuclear Energy Association has organized domestic energy companies to conduct systematic research on retired coal plant sites. This research sampled 149 coal plant sites across 26 provinces, including 110 inland sites and 39 coastal sites. The results showed that after focusing on seismic and population conditions, only 10.07% of the coal plant sites had the potential to be converted for large reactors, while 41.61% were suitable for SMR projects.
The appropriate technology pathway also varies by region and load conditions. Wang Binghua stated that for large, retired coastal coal plant sites, large nuclear units are suitable for providing regional baseload power and can be integrated with applications like seawater desalination and industrial steam supply. For smaller, remote coal plant sites in areas with scarce surface water, advanced reactor types like SMRs and high-temperature gas-cooled reactors (HTGRs) are more suitable.
Some experts at the Repower summit believed that in the short term, if demonstration projects for C2N are to be promoted, a more practical path would be to select suitable coal plant sites in coastal areas and prioritize exploring reactors around 300 megawatts to balance costs. The coastal path offers advantages like relatively lower policy resistance and greater public acceptance and engineering experience, but it also faces challenges such as how to meet the heat and steam demands of nearby industrial parks.
Secondly, the economic attractiveness is not yet compelling.
Nuclear power projects are typical capital-intensive endeavors, with high construction costs and long lead times. Costs are primarily composed of construction, operation and maintenance, fuel, and decommissioning expenses, with construction costs accounting for nearly 50%. The World Nuclear Association points out that while nuclear fuel is inexpensive, nuclear plant construction costs are significantly higher than those for coal or gas, due to the need for special materials, complex safety systems, and redundant control equipment.
Compared to Western nations with older coal power assets, China's industrialization and rapid growth in electricity demand occurred later and faster, leaving a large fleet of relatively young coal units with an average lifespan of only about 10 years. Simply demolishing them to build nuclear plants from scratch may not be economically justifiable. A more feasible approach is to reuse equipment like turbines as much as possible to reduce new construction costs. However, due to significant differences in equipment parameters between coal and nuclear plants, these components require varying degrees of modification for reuse.
SMRs might be more suitable for retrofitting retired coal plants but face even greater economic challenges. The evolution of nuclear technology has historically moved from smaller to larger units precisely to achieve economies of scale and lower the levelized cost of electricity. Therefore, "small" does not necessarily mean cheap; a smaller scale can undermine the economies of scale enjoyed by large nuclear plants. Experts noted that the current per-kilowatt cost of SMRs is approximately 2 to 3 times that of conventional large nuclear reactors. Even if some projects propose compressing the construction period to 40 months and controlling investment to 4 billion yuan, the unit cost would still be higher than that of a large reactor like the Hualong One. Without serialized construction and returns from emission reduction benefits, it would be difficult for the first batch of projects to be commercially viable on their own.
China's SMR technology engineering is at a globally leading stage, currently in the preliminary demonstration and application phase, yet to achieve large-scale commercialization. The currently more mature engineering pathways are high-temperature gas-cooled reactors and small pressurized water reactors. The former is represented by the Shidaowan HTGR demonstration project in Shandong, led by Tsinghua University, which began commercial operation in 2023. The latter is represented by CNNC's "Linglong One" (ACP100), the world's first land-based commercial modular small PWR demonstration project, currently under construction.
Thirdly, regulatory frameworks and related standards need updating.
China's nuclear regulatory system is primarily based on the Nuclear Safety Law of the People's Republic of China, implementing lifecycle management through systems like nuclear facility safety licensing, environmental impact assessment, and operational supervision. Existing nuclear projects are mainly large reactors, and various standards are formulated around them. At relevant seminars, both academia and industry have indicated that applying large-reactor standards to SMRs and new reactor types would make project feasibility very low.
The research published by the China Power Engineering Consulting Group researcher mentioned earlier identified three main issues with China's existing nuclear power siting guidance documents: First, insufficient updates; the documents were issued relatively early, and although there have been minor revisions in recent years, they have not fully kept pace with technological advances and industry development. Second, lack of differentiation; inland and coastal nuclear power siting essentially share the same set of documents, making it difficult to adapt to the more complex siting conditions of inland nuclear power. Third, limited coverage; factors such as social stability, national security, and public participation need further incorporation.
The United States has taken a lead in breaking the ice. In 2026, the U.S. NRC issued the "Risk-Informed, Technology-Inclusive Regulatory Framework for Advanced Reactors" (10 CFR Part 53). The core of this framework is that, without lowering safety goals, it emphasizes risk-informed, performance-based evaluation, allowing different reactor types to demonstrate safety in ways suited to their own technical characteristics.
Wang Binghua recommended strengthening the analysis and demonstration of methods for advanced reactors to achieve safety goals, optimizing SMR siting standards, and improving the feasibility of C2N projects. He noted that the progress in the U.S. nuclear industry has opened a new regulatory pathway for the commercial deployment of advanced nuclear reactors.
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