Will Laser Enrichment Be the Future of Nuclear Fuel?

Say “nuclear renaissance” and what comes to mind is new, advanced reactors, but radical innovation in the fuel supply chain would be crucial to a world with more nuclear power.

The Department of Energy, with a mandate to “re-shore” reactor fuel production, is facing a decision about the vast store of depleted uranium, left over from decades of low-efficiency enrichment work. If the DOE is bold, it could open the door to a third-generation enrichment technology. The moment is ripe as Western companies and governments seek to replace Russia as a supplier of enriched uranium.

That new technology is laser enrichment, which could be used on hundreds of thousands of tons of depleted uranium to scavenge the more fissile uranium isotope, U-235, left behind in the original enrichment process. Deploying laser enrichment technology could reduce the waste disposal burden on the Energy Department and expand critical enrichment capacity without further stressing an already bottlenecked supply of uranium hexafluoride, the chemical form of uranium used in the enrichment process.

Despite extensive work since the 1980s, laser separation remains commercially unproven. And the price for a first-of-a-kind project is not clear. Any project would be high risk—far too high for most private sector investors. But, by an accident of history, it is a risk that the United States is uniquely in position to take.

Making Up for Past Wasteful Behavior

The immediate target for laser enrichment is an unusual stockpile of depleted uranium started by the Manhattan Project, continued by the Atomic Energy Commission, and now under the auspices of the DOE. This is material in which the content of uranium 235 has been reduced below the natural level of .7 percent. But the Energy Department’s stockpile has more U-235 left in it than most other stockpiles, because most of that uranium was enriched in an era before centrifuge enrichment using a more-expensive process called gaseous diffusion. In the 60s through the 90s, it was easier for the department to get the necessary quantities of enriched material by using a lot of uranium, and not being particularly thorough in plucking out the U-235. In addition, before the fall of the Soviet Union, the global market for enrichment was strong, so there was pressure to produce as much enriched material as possible, another reason that the government wasn’t very thorough. Some of the uranium “tails” have a uranium content in the range of .3 to .4 percent, meaning that the enrichment process captured only about half the available U-235.

Russian and European companies did much of their enrichment work later, in a period when demand for enrichment was weaker. Thus they had spare enrichment capacity, and nothing else to use it for, because the centrifuges cannot be turned off once they are running. So Russia and Europe ran the uranium hexafluoride through their centrifuges more thoroughly, processing the same uranium through more cycles, a technique called “underfeeding,” and produced tails at .2 percent U-235 or lower, which is less attractive for re-enrichment.

But as much as the change from gaseous diffusion to centrifuges was a technological leap, another may be coming.

Among the six companies approved by the DOE last October in an ”umbrella contract” as eligible to supply enrichment to the government was GLE, which uses lasers. It wants to start work on Government stockpiles at a former gaseous diffusion plant in Paducah, Kentucky. The material there is already compounded with fluorine, in a form called uranium hexafluoride, which is what is needed for processing with centrifuges or lasers. Eventually, the material will have to be “de-converted,” with the fluorine separated and sold for re-use. The uranium will be combined with oxygen, becoming a form of chemically inert rust. And then it will be buried, probably in Texas.

Processing it with lasers would modestly reduce the volume that must be de-converted and then buried.

“We are waiting for the DOE to issue task orders that have meaningful funding behind them,” said Nima Ashkeboussi, Vice President for Government Relations and Communications at GLE. Congress has allocated $2.7 billion for the DOE to establish an enriched uranium reserve to induce producers to make the material so that it will be ready if and when advanced reactors demand it. Most of those reactors want fuel enriched to nearly 20 percent.

The world of uranium enrichment is small, and the financial details are often opaque. GLE has not said what this would cost, but Ashkeboussi said that a first-of-a-kind plant was an opportunity to learn how to bring costs down. GLE already has a test module running at a GE campus in Wilmington, NC. (GE used to own the technology, but it is now owned 51 percent by Silex, an Australian concern that holds the patent, and 49 percent by Cameco, the big Canadian mining company that also owns part of Westinghouse.)

Ashkeboussi said that his company has acquired 650 acres adjacent to the government’s Paducah facility, and would use 200 acres to build a plant that would raise the U-235 content back up to the natural level of .7 percent. From there the company could raise it to levels useful in a light-water reactor, or it could be sold to another enrichment company to do that work. Today’s reactors run on enrichments of around 5 percent, called Low Enriched Uranium, but advanced models are designed for High Assay Low Enriched Uranium, or HALEU, approaching 20 percent.

A Market Ripe for Change

If laser operation emerges as a commercial contender, it would be entering a market where the underlying economics depend on a complicated mix of history and politics. Russia has about 40 percent of the enrichment capacity globally, and since its invasion of Ukraine, western companies are scrambling to reduce dependency.

Laser enrichment has a long history, thus far inconclusive. Like gaseous diffusion, invented as part of the Manhattan Project, and centrifuges, which supplanted gaseous diffusion in the 1990s, laser enrichment works by exploiting the very small difference in mass between the two natural forms of uranium, U-235 and U-238. In all three methods, uranium is compounded with fluorine, into uranium hexafluoride, or UF6.

Centrifuges work by spinning a few grams of the compound, in its gaseous phase, so that it is subjected to a force hundreds of thousands of times stronger than gravity. Centrifuges spit out two streams of UF6 gas, one very slightly enriched and one very slightly depleted, but when hundreds of centrifuges are arranged in series, the final product can be enriched above 90 percent. The limit for civil uranium is 20 percent.

Lasers, proponents say, do a much more thorough job in a much smaller number of passes. The laser is tuned to a frequency that differentially excites the two kinds of molecules. GLE will not describe the precise mechanism, but published sources hint that it has to do with suppressing the condensation of the molecules with U-235 so they can be separated.

Lasers can work with a smaller physical footprint – and smaller capital expense—because they handle more material than a centrifuge does.

And just as centrifuges made the process smaller and less energy-intensive, laser enrichment would continue both trends, although the energy improvement would be modest compared to the jump from gaseous diffusion to centrifuges, which cut the electricity requirement by more than 90 percent. The two trends make laser enrichment commercially attractive but also raise proliferation concerns.

GLE got a license from the Nuclear Regulatory Commission in 2012 to build a plant that could enrich up to 8 percent, and produce 6 million separative work units, or SWU, a year. (The entire American consumption is about 15 million SWU a year.) But after Fukushima, market conditions were not favorable. Lately, though, the company has been gearing up for expansion.

Adding Flexibility

The industry has historically been hesitant to expand without firm contracts in hand, because the centrifuges are designed to start up and run their entire lifetimes— decades. Lasers, though, can be turned on and off.

GLE is not alone in the field. TerraPower, which is building a fast reactor that will run on HALEU, signed an agreement last fall with the South African firm, ASP Isotopes,, which is developing a laser system for separating isotopes of uranium and other elements. There are other laser technologies in various stages.

Moving towards lasers requires tolerance for risk. Over time, Democrats and Republicans have varied in their outlook on how much risk the government should take to advance technologies that would be of general benefit. Republicans pummeled the Democrats when Obama’s Energy Department loaned $535 million to an innovative solar company called Solyndra, and the company could not repay. Oddly, that ended up being a commercial risk as much as a technical one, because Solyndra’s product was delivered roughly on time and on budget, but was not viable because it had been overtaken by other solar technology.

Trump himself displayed some risk tolerance in 2018, when he signed the law creating the Advanced Reactor Demonstration Project, which heavily subsidizes the construction of two reactors that need higher enriched fuel. More recently, though, the current Trump administration has cast doubt on the value of the Advanced Research Projects Agency-Energy (known as ARPA-E, in imitation of the better-known Defense Department version, DARPA), although the new Energy Secretary, Chris Wright, supports it.

Trump also seems likely to end some work by the Energy Department’s Loan Programs Office, which has also nurtured emerging technologies.

Laser enrichment is the kind of multi-application technology that in earlier years, the Energy Department liked to nurture. In addition to reactor fuel, there are medical isotopes that can be purified with that technology, and the silicon used in computer chips can also be processed using lasers.

Laser enrichment could be another Solyndra. Or it could be like directional drilling, 3D seismic and supercomputing, all advanced by the Department of Energy, and all contributing to the fracking revolution. Looking for an advocate with the financial stamina to try it out, and the raw material that needs processing, the logical candidate is Uncle Sam.

And the stocks of uranium hexafluoride at the department’s former enrichment sites are the logical place to start. That would recover a valuable resource, fissionable uranium, from what will eventually be waste.