Texas Permits a Down-and-Sideways Test Well for America's Spent Nuclear Fuel

The Texas Railroad Commission issued a permit on October 1 to Deep Isolation and Halliburton to drill a full-scale, non-radioactive test well near Cameron, Texas, that drops roughly a mile below the surface before turning sideways into a shale formation the company says has been isolated from groundwater for a million years. The well is a feasibility test, not a disposal site, and the technique is the same one shale drillers have run at scale for two decades.

Spent nuclear fuel is the irradiated fuel that comes out of a commercial reactor once the uranium can no longer sustain the chain reaction. The country has accumulated more than 100,000 U.S. tons of it — roughly equivalent to 91,000 metric tons, per the Congressional Research Service as of late 2022 — stored at about 80 sites in 30-plus states, with another roughly 2,200 metric tons (approximately 2,425 U.S. tons) added every year. The pile sits in pools and dry casks at operating reactors, in aging casks at decommissioned sites, and at the sites of the country's never-finished central repository at Yucca Mountain.

Deep Isolation's approach borrows directly from oilfield practice. A vertical well is drilled to between roughly 0.75 and 2 miles deep, then steered horizontally into a shale layer undisturbed for a million years or more. The waste goes into that horizontal section, encased in a corrosion-resistant canister. A repository that small, the company says, can hold about six years of spent fuel from a single reactor, and the canisters can be pulled back to the surface, which a Yucca-style tunnel sealed with bentonite clay cannot promise.

In an August interview with Fortune, Deep Isolation CEO Rod Baltzer framed the depth and the trajectory as the sale. "We can go twice as deep as a typical [mined nuclear waste] repository, and then follow a formation that's been out of touch with the surface for a million years," he said. The pitch to oil and gas was that this is the same lateral drilling they run every day. "Everybody in oil and gas was like, 'We do this every day,'" Baltzer told Fortune. "And everybody in nuclear went, 'Holy cow, I did not know you could do this and retrieve it. That's amazing.'"

Halliburton is now a partner on the project, providing subsurface, drilling, and well-construction expertise. Halliburton Senior Vice President Steve Haden said the company "will apply its subsurface, drilling and well construction experience to support the deployment of Deep Isolation's technology in a new application." Deep Isolation's engineering lead, Jesse Sloane, called the permit a "major milestone as we move the development of our deep borehole disposal technology into field activities" in the company's October 1 release.

The permit clears the way for a non-radioactive test of the drilling and emplacement process. No spent fuel moves. The test is meant to show that the wells can be drilled, the canisters can be lowered and pulled back, and the shale at depth will hold them. The permitting for actual waste disposal is a separate, multi-agency process that runs through the U.S. Nuclear Regulatory Commission, not a state oil-and-gas regulator.

The binding constraint on U.S. spent fuel is the political work of picking a permanent site. Yucca Mountain has been the symbolic fight for forty years. Deep borehole disposal is a complement to a consolidated storage path, not a substitute for that work, though the retrievability is what proponents think changes the politics: a well that can be pulled back invites a different conversation with the communities that host it.

The next test milestone is the drilling itself. The company has not named a start date, and the Texas permit covers a feasibility well, not a commercial repository. The regulator that matters for actual disposal sits in Washington.