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A new wave of nuclear power plants may be on the horizon as the country and the globe work toward new sources of always-available electricity—but these won’t be your grandfather’s nuclear power plants.
Small modular reactors (SMRs) and even smaller microreactors offer the potential of providing carbon-free, reliable baseload power in a footprint the size of a traditional coal-fired plant or smaller. The reactors incorporate advances in design and fuel technology that make them safer and easier to operate and provide power in the 10-megawatt to 300-MW range.
Several electric cooperatives, from Copper Valley Electric Association, a distribution and generation co-op based in Glennallen, Alaska, to at least four generation and transmission co-ops are exploring the potential of SMRs and microreactors as a long-term generation option that provides 24/7 power with no carbon emissions.
The interest is being driven by rapid advances in the technology and state and federal policy goals to reduce emissions in the electric sector.
“We think that if you value and are serious about that lower-carbon future, then nuclear energy has to be part of the conversation,” says John Carr, vice president for strategic growth at Dairyland Power Cooperative in La Crosse, Wisconsin.
Dairyland has signed a memorandum of understanding with NuScale Power Corp., one of several companies developing advanced nuclear technology, to explore the feasibility of siting and operating an SMR in the Upper Midwest. The G&T serves 24 distribution cooperatives and 17 municipal utilities in Wisconsin, Minnesota, Iowa and Illinois.
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Dairyland’s study of the potential of a NuScale reactor as part of its generation mix is in its early stages, Carr emphasizes. Many more steps, both within the cooperative and on the public and regulatory sides, would be required before moving forward.
“Even if we said today that we want to move ahead,” he says, “it’s 10 years down the road to be operational, maybe more.”
That reflects the state of the SMR and microreactor industry overall. Although several companies have developed or are developing the technology, significant hurdles remain before commercial adoption. Cost is one of the biggest.
Dan Walsh, NRECA’s senior director of power supply and generation and a member of the NuScale advisory board, says the price tag per kilowatt-hour is still “many orders of magnitude higher” than a combined-cycle gas power plant.
Those prices, Walsh notes, will come down as research and investment continue and companies develop standardized construction methods and supply chains. “We need to figure out how to build these on budget and on time in the U.S.,” he says. “It’s just going to take time.”
Getting to zero
Nuclear power has long been a source of generation for many cooperatives, providing nearly 15% of the fuel mix for 661 cooperatives. All that power comes from traditional light-water reactor plants. All told, the country has 93 commercial nuclear reactors operating in 28 states.
But the number of reactors has been shrinking, and they now average 40 years in age. When the Tennessee Valley Authority’s Watts Bar Unit 2 near Spring City, Tennessee, came online in 2016, it was the first new reactor to begin operations since 1996. Currently, 25 reactors are scheduled for decommissioning.
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Related: Listen to an episode of "Along Those Lines" on small modular nuclear reactors.
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Costs, siting requirements and public concerns about radioactive waste management and safety have been ongoing challenges for large-scale nuclear plants. But as the nation trends toward ambitious carbon-reduction goals, the grid still requires reliable baseload generation that doesn’t depend on the wind blowing or the sun shining.
In the Midwest, Carr notes, the Midcontinent Independent System Operator (MISO) experienced a capacity shortfall in meeting its planned reserve margin this year. The region avoided any widespread outages, he adds, but some utilities delayed the planned retirement of coal power plants to aid in maintaining regional capacity.
“When we look at our own resource plan, we’re able to identify how we can cut our CO2 emissions by roughly 50% from 2005 to 2030,” Carr says. “But we have a tough time seeing how we can get to zero or net-zero with just wind or solar alone.”
The cost of an SMR plant today means Dairyland would need a partner to go forward, Carr says.
Copper Valley Electric would also need a partner or a research grant for a microreactor, says Travis Million, Copper Valley CEO. But both men say the possibilities of the technologies make them worth exploring.
NuScale’s design is a small light-water reactor that operates on the same basic principles as a larger reactor, using enriched uranium fuel rods to heat water and drive a turbine, but incorporates a simplified, modular design that means the reactor measures only 65 feet long and 9 feet wide. It sits inside a slightly larger containment vessel and is designed to be located underground in a pool of water, providing an extra measure of safety. It could be transported to a site by rail or truck.
“These facilities are of a size that you could fit them into a former coal plant site,” Carr adds, which means interconnections to the transmission system would already be in place. The locations would also present employment opportunities to replace those lost from coal plants being decommissioned.
Other companies such as Terra Power and Westinghouse Electric are pursuing SMR or microreactor designs as well. Copper Valley Electric has been working with Ultra Safe Nuclear Corp., which has developed a microreactor that uses fuel made up of small spheres of uranium coated with a ceramic layer known as “TRISO particle fuel.” Each pellet essentially creates a protective shell for the fuel to increase safety and stability. The reactor is a modular unit that could provide 10 MW of power and up to 30 MW of thermal energy.
‘A real opportunity’
Copper Valley now gets 75% of its power from hydroelectric plants, but it’s highly seasonal. The co-op depends on diesel generation to provide reliable generation during winter months. The high cost of diesel fuel along with its carbon emissions has Copper Valley looking for an alternative, Million says.
The co-op has studied wind and geothermal, but neither is practical for its service territory. Solar would work during Alaska’s long summer days, but that’s when hydro plants are running. As they considered their options, “my board was unanimously supportive of exploring microreactors,” he says.
The cooperative recently completed a feasibility study with Ultra Safe.
“The three biggest drivers we were looking at were safety, potential environmental concerns and cost to our membership,” Million says. “That’s what we heard from our membership as well.”
A key part of the process, he notes, was public education.
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“We got out in front. Right as we started getting into the feasibility study, we started having public meetings with our members,” Million says.
Carr also sees educating the public on the technology and gaining public acceptance as central challenges moving forward with SMRs.
Two questions Copper Valley Electric faced involved the size of the facility and how spent fuel would be handled.
“When they saw just the size comparison—we’re talking two football fields as opposed to 50 acres—so many people came around and said, ‘Oh, this is not what we were thinking when you talked about nuclear power,’” Million says.
The fuel in the microreactor design has a 20-year lifespan and, when ready for disposal, would fit in a 55-gallon drum, he says. Ultra Safe Nuclear says it would take the responsibility for removing the fuel and safely disposing of it.
“That really eased a lot of tensions as well,” he notes.
Copper Valley Electric’s board will now take up consideration of a microreactor.
“Cost is still the big driver,” Million acknowledges. “This would never pencil out if we had to do it on our own.”
He anticipates a decision on whether to proceed in spring or early fall.
But down the road he believes the new wave of nuclear reactors will become an important zero-carbon option for the electric utility industry.
“Once costs come down,” Million says, “I see this as a real opportunity for co-ops nationwide.”