Bloomberg Law
July 8, 2022, 9:30 AM

Mini Nuclear Reactors Land in Scientific Spat Over Waste Output

Daniel Moore
Daniel Moore

A public fight over an academic study that cast doubt on advanced nuclear reactors’ waste promises has heightened a rift between supporters and skeptics of the technology as policy-makers seek to boost nuclear’s role in meeting climate-change goals.

The fight has thrust the new reactor designs into one of nuclear energy’s political liabilities: the unaddressed question on what to do with nuclear waste.

The study, co-authored by a former Nuclear Regulatory Commission chair, has come under fire from advanced reactor developers who argue it relied on outdated design criteria and skewed the volume of waste that could be generated in the future. One developer, NuScale Power, has demanded a correction.

The study’s three authors contend they sought most complete and independently verifiable information available—and that the data challenges and industry backlash points to a key problem in assessing a poorly understood component of the technology.

The industry has yet to cite a technical flaw that changes the study’s findings, said lead study author Lindsay Krall, who was a MacArthur postdoctoral fellow at Stanford’s Center for International Security and Cooperation.

“Small modular reactors will not alleviate the burden of nuclear waste,” Krall said. “More likely, they will make our nuclear waste issues worse.”

Smaller Reactors

Developers have touted 21st-century reactors as less expensive to build and having reduced environmental footprints than the current fleet of light-water reactors that date back more than 50 years. The designs envision smaller, stackable reactors that can have different fuel and cooling systems.

Nuclear’s zero-carbon profile is appealing to a bipartisan contingent of lawmakers, officials, and others looking for climate-friendly electricity. Small modular reactors, or SMRs, have drawn investors including Bill Gates and Warren Buffett.

Today, the Energy Department has backed 10 advanced reactor designs, spending billions of dollars to demonstrate the technology can work. The Nuclear Regulatory Commission is developing a new set of licensing regulations that can more easily review advanced reactors.

But US nuclear waste policy hasn’t budged. The situation has forced current operators to store some 86,000 metric tons of waste at 75 power plant sites in 33 states, according to a Government Accountability Office report published last year.

Policymakers have been deadlocked since 1987, when Congress designated Yucca Mountain, about 90 miles northwest of Las Vegas, as the sole permanent U.S. burial site. Nevada politicians and local communities largely oppose Yucca Mountain, and the Obama, Trump, and Biden administrations have mothballed it.

The Energy Department has initiated a consent-based process for siting interim nuclear waste facilities. The NRC also has been assessing interim sites in Texas and New Mexico—but both have generated opposition from those states’ governors.

The industry is marching forward, eyeing college campuses, hospitals, and communities for research and eventual reactor deployment. In May, Purdue University and Duke Energy announced plans to explore the feasibility of a small modular reactor to meet the long-term energy needs of the school’s West Lafayette, Ind., campus.

A Purdue spokesman told Bloomberg Law it was too early to say whether SMR waste studies would be a part of the research.

Debate Over Data

On May 30, the Proceedings of the National Academy of Sciences published the study by Krall and others. Examining three reactor designs from NuScale Power, Terrestrial Energy, and Toshiba, the authors concluded small modular reactors could generate more nuclear waste than the current fleet of reactors by a factor of two to 30.

The backlash was almost immediate. On June 2, NuScale published a letter to the journal’s editor highlighting a “factual error,” saying the researchers ignored data from a more updated and larger version of NuScale’s reactor. Using that data, which was provided to the researchers, waste streams are within the values typically seen in light-water reactors, wrote Jose N. Reyes, NuScale’s co-founder and chief technology officer.

The academy’s editorial board is evaluating NuScale’s letter, academy spokesman Prashant Nair said.

The authors, in a joint letter and in interviews, defended their decision to analyze NuScale’s 160-megawatt reactor. Its design specifications had been submitted to the NRC for certification and review, providing a source they could reference.

“It took a long time to find the data, to do the calculations—but it’s important to understand,” study coauthor Allison Macfarlane, a University of British Columbia professor who chaired the NRC from 2012 to 2014, told Bloomberg Law.

When she left the commission, Macfarlane discovered that while new reactor designs had grabbed attention, the projected waste impacts were subject to little scrutiny.

“Shouldn’t you understand the waste impacts of an energy source before you launch into an energy source? Isn’t that responsible?” Macfarlane said. “This study’s just a first effort towards that.”

Not a Dealbreaker?

The industry and its supporters say the study cast an unfair and biased focus on a problem that government officials for decades have failed to solve.

“Something at some point needs to be done about waste, so it is valuable to have these conversations,” said Adam Stein, director of nuclear energy innovation at the Breakthrough Institute, an environmental think tank. “It is not valuable to do it in a skewed manner that comes to a conclusion one way or the other to fulfill an objective instead of just following the science.”

It’s not surprising developers sought to “correct the record,” said John Kotek, senior vice president of policy development and public affairs for the Nuclear Energy Institute, an industry trade association. But he thinks the study won’t change the way society views nuclear.

“The bigger picture to me: Is this going to have a meaningful impact on the decisions that utilities and energy planners are going to make when it comes to the future energy mix?” Kotek said. “And I just don’t think it is.”

While the study raises important points, some of the reaction on both sides may have been overblown and obscuring nuclear’s overall importance to the US energy mix, said Chuck Mason, a University of Wyoming professor and university fellow for research organization Resources for the Future.

The waste concern is “worth paying attention to,” Mason said, but “it’s miles away from a dealbreaker.”

To contact the reporter on this story: Daniel Moore in Washington at

To contact the editors responsible for this story: Chuck McCutcheon at; Zachary Sherwood at

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