Radiant Industries has scrapped its proposal to build a nuclear microreactor manufacturing facility outside the Natrona County town of Bar Nunn and announced it plans to build “its first mass-produced Kaleidos microreactor” facility in Oak Ridge, Tennessee, “on a Manhattan Project site.”

The announcement came Monday afternoon in the form of a letter-to-the-editor from Radiant Senior Director of Operations Matt Wilson and a press release announcing the company’s new focus on building the facility in Tennessee. The company cited Wyoming’s decades-long ban on storing spent nuclear fuel waste.

“Our decision came down to regulatory certainty,” Wilson said. “Our plan was to build our nuclear generators in the Cowboy State, using Wyoming-mined uranium, send them to customers (like our troops at remote bases), and bring them back for refueling, with the used fuel being safely and temporarily stored in above-ground containers at our factory.”

Wyoming lawmakers made a narrow exception to the state ban in 2022 to accommodate TerraPower’s Natrium nuclear plant being built near Kemmerer. That exception allows nuclear power plants operating in the state to “temporarily” store their own radioactive waste. But it doesn’t allow waste from nuclear power plants outside the state.

Radiant Director of Operations Matt Wilson speaks to a full house at the Bar Nunn Community Center in March 2025. (Tommy Culkin/Oil City News)

Nuclear energy supporters have backed, without success, several proposals in recent years to make more exceptions to accommodate other nuclear waste storage proposals, such as Radiant’s. A legislative committee tabled such a measure in July.

“Radiant was only seeking to safely and temporarily store used fuel from Wyoming-built reactors returned from deployment,” Wilson wrote. “Sadly, Wyoming’s law currently does not accommodate that model.”

California-based Radiant also faced significant opposition within Bar Nunn and beyond, mostly due to its plan to store spent nuclear fuel at the manufacturing facility — which would have been located close to Casper, Wyoming’s second-largest city. Though the company found many supporters, as well as many others who were on the fence seeking details and assurances regarding safety, a group formed to oppose Radiant’s Bar Nunn proposal and began collecting signatures. 

“Bar Nunn does not want nuclear waste,” Midwest Republican Rep. Bill Allemand told a crowd of about 200 in July during a meeting he organized in Bar Nunn. “We want manufacturing. We would love for Radiant to come here and manufacture and put the waste somewhere else.”

Retired uranium miner Wayne Heili delivered a “nuclear 101” presentation at Casper College in September. (Dustin Bleizeffer/WyoFile)

Retired Wyoming uranium miner Wayne Heili, who recently held a “nuclear 101” presentation at Casper College and generally supports nuclear energy proposals in the state, told WyoFile he is disappointed. 

The Legislature’s Minerals, Business and Economic Development Committee, he said, “had an opportunity earlier this year to move something forward, and they didn’t. That left Radiant looking at uncertainty.

“It’s a sad outcome for business development in Wyoming,” Heili added. “That’s the legacy of nuclear, though. No matter where you are, somebody’s going to show some concern.”

Green River Republican Sen. Scott Heiner, who co-chairs the Interim Minerals Committee, said Radiant pressured lawmakers to move too quickly to change state law to accommodate its plans, noting that most lawmakers only learned of the company’s proposal earlier this year.

“They’ve made their decision before we’ve had a chance to go through the whole legislative cycle,” Heiner told WyoFile on Monday. “We took public testimony, we tabled the decision until later, and they’ve decided to go.”

Heiner added, “They’ve held that over our head for the whole time: ‘If you don’t approve this, then we’re going to go to Tennessee.’ Well, something that huge, you don’t rush it.”