David Turk, left, deputy secretary for the U.S. Department of Energy; and Kathryn Huff, center, assistant sectary for DOE’s Office of Nuclear Energy, with Centrus executives inside the company’s new uranium enrichment plant in Piketon, Ohio.
David Turk, left, deputy secretary for the U.S. Department of Energy; and Kathryn Huff, center, assistant sectary for DOE’s Office of Nuclear Energy, with Centrus executives inside the company’s new uranium enrichment plant in Piketon, Ohio. Credit: Centrus Energy Corp. / Courtesy

As an Ohio uranium enrichment plant opened this month, yet another study questioned whether nuclear power from small modular reactors can compete with other types of electricity generation.

Centrus Energy’s new plant in Piketon produces high-assay, low-enriched uranium, or HALEU. The fuel will contain between 5% and 20% fissile uranium, or U-235, which is the range needed for various types of small modular reactors, or SMRs. The current fleet of large nuclear reactors uses fuel with up to 5% U-235.

Large nuclear plants have had problems competing with other types of electricity generation in recent years. Ohio’s House Bill 6 would have mandated ratepayer spending of more than $1 billion to subsidize the 894-megawatt Davis-Besse plant and 3,758-megawatt Perry plant in Ohio, for example. Lawmakers repealed that law’s nuclear subsidies after alleged corruption came to light.

Now the question is whether small modular reactors designed to produce up to 300 MW of electricity can compete better.

Huge gigawatt-scale nuclear plants can have economies of scale because their power output grows faster than increases in capital and operating expenditures.

“However, the extensive customization of many of the currently deployed reactors undercuts much of that economy,” said William Madia, a nuclear chemist and emeritus professor at Stanford University who is now a member of Centrus’ board of directors.

The lack of a standard design also makes it harder for large reactors to get replacement parts when needed. “Things like large-scale forgings are in short supply globally,” Madia noted.

In contrast, small modular reactors can be built in indoor factories and then sent to where they’ll be used. That avoids site-by-site mobilization costs, as well as weather problems that might interrupt construction.

“But the real driver is standardized design,” Madia said. So eventually, production can take place on assembly lines. And that should produce its own economies.

All in all, “the capital cost for SMRs is much lower than GW-scale machines,” Madia said. Also, if the choice is between lower-cost modular reactors and huge ones, “many, many more utilities can afford a few billion dollars on their balance sheets. Very few can handle $10-plus billion.”

Facing competition

No small modular reactors are operating commercially in the United States yet.

“Right now, if you’re looking to spend money on bringing new generation online, you have tech that you know works with wind and solar and storage,” said Neil Waggoner, federal deputy director for energy campaigns at the Sierra Club.

An analysis published this month by the journal Energy estimated the levelized cost of electricity, or LCOE, for different types of small modular reactors. The LCOE basically reflects the average costs for producing a unit of power over the course of a generation source’s lifetime.

Small modular reactors “seem to be non-competitive when compared to current costs for generating electricity from renewable energy sources,” the Energy study found.

Comparing intermittent resources like wind and solar to “dispatchable resources with small land footprints is a flawed exercise,” said Diane Hughes, vice president of marketing and communications for NuScale Power. Nuclear energy from small reactors requires little new transmission infrastructure, she added. So, “the cost per plant is comprehensive in a way that one solar array or wind farm is not.”

Yet the Energy study found renewables would still be more competitive even with added system integration costs that would roughly double the levelized cost of electricity.

“These costs can stem from batteries, but there are also many other means of flexibility that can be used,” said Jens Weibezahn, one of the study’s corresponding authors and an economist at the Copenhagen Business School’s School of Energy Infrastructure.

Weibezahn’s group got similar results when they compared the projected market value for energy from small modular reactors with the weighted market value for renewable electricity at the time of generation. Costs for dealing with radioactive waste “will add a significant additional economic burden” on nuclear technologies, he added.

A March 2023 study by Colorado State University researchers suggested the economics for SMRs wouldn’t be dramatically better than those for large reactors. The researchers also found the levelized costs of electricity for different types of small modular reactors would be substantially higher than that for natural gas power plants without carbon capture.

However, “natural gas plants release tremendous amounts of greenhouse gases which engender societal and environmental costs,” said the paper in Applied Energy. Adding in carbon capture increased the estimated levelized cost of energy for the natural gas plants to the general range for the small modular reactors.

Commercial methane-fired power plants with carbon capture are not yet running at scale. The American Petroleum Association has objected to proposed rules that might effectively require such equipment.

How things will shake out in the future is unclear, said Jason Quinn, who heads the sustainability laboratory at Colorado State University and is the corresponding author for the March study. But, he added, “typically decisions are driven on economics, and current SMR estimates show them not to be a commercially viable solution as compared to other technologies.”

The row of white columns are centrifuges that began running this month to produce HALEU at the new Centrus plant in Piketon, Ohio. Open space in the plant can hold hundreds more centrifuges when commercial production ramps up.
The row of white columns are centrifuges that began running this month to produce HALEU at the new Centrus plant in Piketon, Ohio. Open space in the plant can hold hundreds more centrifuges when commercial production ramps up. Credit: Centrus Energy Corp. / Courtesy

SMRs coming to Ohio

For now, initial production at the Centrus HALEU plant will meet a commitment to the Department of Energy. Centrus expects the plant will employ up to 500 direct employees when it moves to full-scale commercial production, said Larry Cutlip, vice president for field operations. Supporting industries will provide work for another 1,000 to 1,300 people. And all those workers could stimulate economic activity for roughly eight times as many jobs, he added.

Centrus already plans to supply HALEU fuel to TerraPower and Oklo, Inc. Each company has its own individual SMR design and is working with the Nuclear Regulatory Commission toward having the designs certified.

Oklo plans to build two sodium-cooled fast reactors in Piketon near the Centrus’s HALEU production plant. Each of the SMRs could supply up to 15 MW of electricity and more than 25 MW of clean heating, said spokesperson Bonita Chester.

Plans call for the SMRs to supply some carbon-free electricity for the Centrus facility. Other possible customers for electricity include commercial, industrial or municipal entities.

“As for the clean heating output, we envisage potential industrial partners and applications for district heating systems,” Chester said.

The ability to sell or otherwise use the heat as well as electricity could potentially lower the average costs.

“We are committed to ensuring that our electricity and heating output remain competitive with other forms of energy generation,” Chester added. “Our technology benefits from simplified design and cost-effective materials, making it an economically effective option.”

NuScale plans to deploy a dozen 77-megawatt small modular reactors in Ohio and another dozen in Pennsylvania for Standard Power data center projects by 2029. Those pressurized water reactors can use low-enriched uranium and won’t need HALEU, Hughes noted.

Deputy Secretary of Energy David Turk expects HALEU and small nuclear reactors that rely on it will be competitive.

“People appreciate the importance of baseload power, and I think that will be even more important as we further decarbonize the electricity economy,” Turk said. That will appropriately include more wind and solar energy, “but it’s good to have that baseload power to make it all work in the end.”

Electricity from SMRs will be “a real source of energy security and energy resilience,” Turk added. “You need diversification, but you need to have a variety of different inputs going into the system.”

“Nuclear certainly can provide baseload, but it does this at a cost significantly higher than an integrated renewables-based system,” Weibezahn said.

A bigger question may be whether there will be enough carbon-free electricity.

The Department of Energy estimates the United States will need to triple nuclear energy production to about 300 GW by 2050. That growth will be driven by advanced nuclear technologies, much of which will use HALEU.

“If we want to meet our climate goals and meaningfully reduce carbon emissions, we need all sources of clean energy, including wind, solar and nuclear energy,” said Jess Gehin, associate lab director for nuclear science and technology at Idaho National Laboratory. “Current projections show that we cannot meet our climate goals without nuclear energy.”

Kathi is the author of 25 books and more than 600 articles, and writes often on science and policy issues. In addition to her journalism career, Kathi is an alumna of Harvard Law School and has spent 15 years practicing law. She is a member of the Society of Environmental Journalists and the National Association of Science Writers. Kathi covers the state of Ohio.