Could allowing more nuclear power help Minnesota’s switch to carbon-free electricity?

Nuclear Generating Plant is seen
Xcel Energy’s Prairie Island Nuclear Generating Plant is seen through a gate from Wakonade Drive in Prairie Island Indian Community in Welch, Minn., in June.
Tom Baker for MPR News 2022

Updated: 3:45 p.m.

Nuclear power has been producing electricity in Minnesota since the 1970s, and generating controversy for just as long.

Minnesota's two nuclear plants, at Prairie Island and Monticello, supply nearly a quarter of the state's electricity. However, a moratorium prohibits new nuclear plants from being built in Minnesota.

Some state lawmakers and clean energy advocates think it's time to reconsider whether modern nuclear technology should be part of Minnesota's future.

A bill under consideration at the state Capitol would require the state commerce department to study the potential costs, benefits and impacts of generating power with advanced nuclear technology.

Giving new momentum to the longstanding debate: Minnesota’s new state law requiring electricity to come from carbon-free sources by 2040. The study would look at whether nuclear energy could help the state meet that mandate.

It would also look at the economics of replacing coal-fired power plants with advanced nuclear reactors. The bill authorizes $300,000 for the study.

Authorizing a study — or even lifting the moratorium — doesn’t guarantee more nuclear energy in Minnesota, said the bill’s author, state Sen. Andrew Mathews, R-Princeton.

“It's to have the tool in the toolbox,” he said. “So that we can decide if there's a point in time where that tool is needed or that tool makes sense. We have it there and we can use it.”

What’s driving the debate?

One factor is the new state law requiring electric utilities to get 100 percent of their electricity from carbon-free sources by 2040. Gov. Tim Walz signed it into law on Feb. 7.

Utilities are expected to add a lot of solar and wind to help reach that goal. But nuclear advocates say they also will need a reliable, consistent source of energy when the sun isn't shining or the wind isn't blowing.

Unlike coal or natural gas, nuclear plants don't emit greenhouse gases that contribute to climate change, such as carbon dioxide.

Mathews said nuclear meets the definition of a carbon-free energy source, but electric utilities can't consider it under the current law.

“They could start to conceive and at least make plans and figure out, does this make sense? Is it cost effective? Does this meet our needs in an affordable and reliable way?” he said. “With the moratorium in place right now, we can't even have those discussions.”

A rather unusual coalition supports Mathews' bill, including some climate advocacy groups, trade unions and the Minnesota Chamber of Commerce.

Fresh Energy, a nonprofit advocacy group, wrote that advanced nuclear technology “does have significant potential and is worth considering as a serious option,” as the state works to eliminate carbon emissions from the power sector.

Eric Meyer, founder and director of a nuclear advocacy nonprofit called Generation Atomic, said many people he talks to are surprised to learn that Minnesota still gets about a quarter of its electricity from coal, and that it’s illegal to build new nuclear plants in the state.

“When you hold up a (uranium) pellet and tell people that this is the equivalent to a ton of coal in terms of its energy value — for a lot of people, it’s like, ‘Wow, this is the closest thing we have to magic,’” he said.

Advanced nuclear technology – what is it?

Advanced nuclear technology is a broad term that applies to many new types of reactors being developed, said Patrick White, project manager with the Nuclear Innovation Alliance. It’s a nonprofit think tank that promotes advanced nuclear energy as a climate solution.

They vary, but there are some common elements. First, there’s a difference in size. Traditional nuclear plants are large, often 800 to 1,000 megawatts, and can produce enough electricity to power a million homes.

Advanced reactors are being developed in a range of sizes, but they’re generally smaller — from only a few megawatts to generate enough electricity for a couple of thousand homes, up to a few hundred megawatts.

Also, the technology is different.

All nuclear plants in the U.S. are what are called light-water reactors. They use ordinary water to cool the reactor, and slow down the neutrons that are emitted during fission, to keep the chain reaction going.

“With advanced reactors, it's really a whole suite of different technologies, different types of fuels, different types of coolants,” White said. “Each one is going to have its own unique advantages and potential benefits.”

Advanced reactors also are designed to be more flexible and adaptable, so they could be installed in more places, possibly to supplement wind and solar energy and battery storage.

Earlier this year, federal regulators approved the design for a demonstration project in Idaho that would be the first small modular reactor in the US. There are other projects in development around the country, although some have faced delays. 

Smaller reactors – safer?

Safety has always been a major concern with nuclear plants, especially the unlikely but potential threat of a catastrophic meltdown or accidental release of radiation.

Proponents of advanced nuclear reactors say they’re safer than conventional plants, partly because of their smaller size.

Conventional plants have complex systems that require backup generators to keep the reactor cool in the event of an accident. Advanced reactors are less complex, so there are fewer points where something could go wrong.

And they also have more safety features built into the design that don't rely on humans intervening if there's an equipment failure — features White calls “passive safety.”

“So instead of necessarily having to pump water into your system, what if the water would just naturally flow through the system using gravity and natural convection?” he said. 

Some reactors are being designed with the main components underground, so they are less vulnerable to attack or natural disaster.

Waste: a long-term problem

One drawback of nuclear power is the leftover spent fuel that remains radioactive for tens of thousands of years. 

It’s a key reason why many environmental and Indigenous groups have opposed the expansion of nuclear energy in Minnesota in the past.

Advanced reactors do produce nuclear waste similar to conventional plants. Pro-nuclear advocates say it potentially could be stored safely underground or possibly recycled, since it still contains energy.

Currently, Xcel stores spent fuel from its two Minnesota nuclear plants in casks at the plants, because there is still no federal repository despite years of debate.

One group that has voiced concerns about the storage of nuclear waste is the Prairie Island Indian Community. The tribe has long objected to spent nuclear fuel being stored at Xcel’s Prairie Island plant, and it does not want any more.

“Every day, we bear the burden of our nation’s failed nuclear waste disposal policy,” tribal leaders wrote in a letter to state lawmakers. 

They said the Prairie Island community does not oppose nuclear power.

“However, until there is a mechanism in place for the safe storage of nuclear waste, we will not support the construction of new nuclear power and, by extension, the creation of new nuclear waste,” they wrote.

Xcel Energy, which owns the two nuclear plants in Minnesota, said it plans to continue operating them to help it achieve carbon-free electricity. 

Xcel supports the idea of a study. It already has plans to reach 80 percent carbon-free electricity by 2030, but says it will need to explore new technologies that can generate electricity 24/7, and advanced nuclear power is among those.

But Xcel says any study also needs to consider what happens with the spent nuclear fuel.

Other hurdles

The Senate energy committee laid the bill over to possibly include in a budget bill. A House bill authored by Rep. Zack Stephenson, DFL-Coon Rapids, was introduced on Thursday.

But aside from state policy, federal rules would also have to change to allow this new technology to take off.

The Nuclear Regulatory Commission has extensive regulations, but they were written decades ago for large, light-water reactors. 

There's also the hurdle of public opinion. Polls show Americans are still divided about whether they support nuclear energy. And it's still not clear whether people would embrace having a reactor in their community.

White said he understands that people might feel it’s premature to repeal the nuclear moratorium. But he thinks a study is a good compromise to get more information and figure out the best next step.

“At the end of the day, we think that this is a technology that ultimately has a lot of benefits,” he said. “And we want to make sure that people feel like they're making the right decision.”

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