The Future of Nuclear Energy Comes Down to the Fuel

Advanced reactors are on the way, but the United States isn’t making the fuel to run them.

The Future of Nuclear Energy Comes Down to the Fuel

One of the problems that made the Dark Ages so dark is that engineers couldn’t make concrete. The Romans had made lots of it, but the Medievals lost the recipe. In turn, an excellent network of roads broke down, and new buildings were less durable, contributing to a general decline in living conditions.

We’re doing something similar now with nuclear.

In particular, we used to know how to make fuel for nuclear reactors, but we just can’t seem to do it now. The task at hand is to prepare uranium fuel for advanced reactors, reactors designed to work well with wind and solar on the grid, to replace coal plants, and to do other kinds of work besides making electricity—all in the quest for a zero-carbon economy.

If we don’t figure out a way to make that fuel now, we will delay the startup of first-of-a-kind advanced reactors on which we’ve spent billions. Construction of subsequent plants will slip into the future, and the goal of a zero-carbon energy system by mid-century, already hard, will become harder.

What type of uranium do advanced reactors need?

Nature gives us uranium in two types, one rare and one common, and most reactors run on a blend that has more of the rarer type than nature provides. The technology for separating these two types of uranium, a process called “enrichment,” was invented in the United States and was first used on an industrial scale 70 years ago. But the advanced reactors that are now moving toward construction want a blend that is even richer in the rare type, and it seems unlikely that we can produce that blend in time.

For non-physicists, here are the geeky details in three sentences:

  • Natural uranium is 1 atom of U-235 in every 139 uranium atoms. Fuel for today’s reactors is 1 atom of U-235 per 20 atoms of uranium, known as Low Enriched Uranium.
  • Some advanced reactors need a blend that is just under 1 U-235 atom per five uranium atoms, known as High Assay Low Enriched Uranium, or Haleu.
  • But get to 1 U-235 atom per five uranium or above, and you have Highly Enriched Uranium, which the United States has been working hard to keep out of international commerce because of its military uses.

Making Haleu shouldn’t be a problem; for decades, we produced a blend that was nine atoms of U-235 per 10 atoms to make atomic bombs and to make the highly enriched uranium used for propulsion reactors on aircraft carriers and submarines.

But somehow, in the commercial sector, we can’t seem to produce anything above Low Enriched Uranium. In the next six years or so, we are likely to have the first few advanced reactors waiting to start up, with no fuel for them in sight.

Why can’t the United States make Haleu for its reactors?

How can a society with such an advanced technology fail to mobilize it to meet pressing environmental problems like climate change? At the moment, the problem with saving the environment is environmental procedures. Haleu may be important to saving the climate, but we also have to check twice that making the fuel, something we’ve been doing for years, won’t hurt the environment.

It would be ironic and even silly to waste precious time for unnecessary environmental reviews. How did we get into this blind alley? A bit of history:

The U.S. government once had a monopoly on enrichment, but its production came from energy-intensive plants left over from the Manhattan Project. And it failed to ever modernize them. Indeed, those plants were eventually shut down for economic reasons, and the U.S. industrial base for enrichment withered as other countries moved to cheaper centrifuges instead.

But there was a giant, easy alternative source: The Soviet Union and then the Russian Federation. First, the USSR diluted high-enriched uranium originally intended for bombs and sold it for use in U.S. power reactors. Later, Russia, with about 36 percent of the world’s enrichment market, seemed like the obvious source for Haleu. But then Russian President Vladimir Putin invaded Ukraine, and that source became untenable. (Although the United States still buys some enrichment from Russia.)

Now we’re in a scramble to establish a domestic source, which essentially means re-piping the centrifuges we’ve been using for years, to run the uranium through a few more cycles to raise the blend of U-235. There are some other issues, too, although they are lesser and solvable, including making sure that the shipping containers are appropriate for a higher blend.

But at the moment, the Energy Department wants to do an Environmental Impact Statement before it spends the money that Congress has set aside for providing Haleu. There are three reasons why this doesn’t make sense:

  • One is simple government procedure: Factories that make Haleu will eventually be licensed by a different agency, the Nuclear Regulatory Commission, and the NRC will include an environmental assessment.
  • The second is that enriching uranium to a slightly higher blend isn’t going to have an impact different from the enrichment we do now.
  • The third is that we’re losing sight of the big picture. An environmental impact statement would be like studying the feng shui of the deck chairs on the Titanic.

Is there any other way to fuel the reactors?

Until the Energy Department screws its head back on, there is another possible source for Haleu; the government has many tons of surplus high-enriched uranium, which it could dilute to the levels needed for advanced reactors. But it says it doesn’t have the hardware to do that work, and it seems unlikely that it will build it anytime soon.

And so we are back in a familiar place. The world’s carbon pollution problems will be solved by new inventions, nuclear prominent among them. Congress is finally appropriating money as if the problem is urgent, but federal agencies sometimes aren’t acting that way.