America gets one-fifth of its power from nuclear power plants. Nuclear is far and away the cheapest and most reliable alternative to carbon-emitting coal. Yet we all know that nuclear energy carries one great big negative: the problem of nuclear waste, the radioactive residue from enriched uranium.

Now, suppose there were a solution to this problem? A solution that reduced the amount and the toxicity of nuclear waste by 80 percent or more? That would be useful, right?

Well guess what—it’s doable. Better yet—it’s done.

This week, I visited a facility in Normandy where France reprocesses the water from France’s 58 (soon to be 59) nuclear reactors, as well as waste from reactors in other European Union countries and Japan.

Used uranium is removed from reactor cores and chemically manipulated to restore its radioactivity. This process creates new fuels—and only small amounts of waste byproducts. The process can be repeated a third time and perhaps a fourth.

Yet in the United States, where reprocessing was invented, used uranium is simply discarded.

The result is highly wasteful: The once-used uranium still retains 96 percent of its energy potential. The result is likewise highly dangerous: That 96 percent potent uranium also retains a corresponding proportion of its toxicity to human life. So why do we not reprocess?

The decision was not made by accident. Back in the 1970s, the U.S. made a conscious policy decision to shut down its reprocessing facilities. The decision had nothing to do with energy policy, and everything to do with that era’s arms control illusions.

One of the byproducts of reprocessing uranium is plutonium. The plutonium produced by a civil reactor is not weapons-grade. It can be used as a fuel itself, and in France it is. But theoretically, this low-grade plutonium could be reprocessed again and again and enriched to a point where it could be used as a weapon.

On the basis of this fact, the Carter administration decided that the U.S. must eschew reprocessing altogether. It reasoned as follows: If the U.S. civil nuclear program permitted any reprocessing, even for fuel purposes only, that would compromise U.S. efforts to persuade other countries not to reprocess. And (the reasoning continued) an across-the-board ban on reprocessing was the only way to ensure against nuclear proliferation.

This reasoning lacked cogency, to put it very mildly.

First, even assuming that other nations cared about the example set by the U.S. civil nuclear program, they were bound to notice that the U.S. also maintained a military nuclear program. "Do as we say, not as we do," is not a principle likely to carry much weight.

Second, the notion that other nations would forgo nuclear weapons because we set them an example was naïve at best, narcissistic at worst. Does Iran care that the U.S. does not reprocess? Does North Korea? States make their nuclear decisions for their own reasons.

States that have drawn back from the nuclear threshold—Brazil, Argentina, and South Africa being the outstanding examples—have done so because a) new, democratic governments replaced nondemocratic governments and preferred to spend their money in other ways; and b) they feared inspiring counter-proliferation by their immediate neighbors. The only other motive that seems to work is c) the direct application of force, as with Israel against Iraq.

Gandhian self-sacrifice, by contrast, has had zero effect.

It is long past time to cease treating nuclear energy as a subordinated poor cousin of nuclear weapons-making. This past week, I had an opportunity to visit French nuclear facilities as a guest of the U.S. Nuclear Energy Institute. At the end of the trip, I was taken to the large concrete-lined below-ground chamber in which the French store the most hazardous of the nuclear wastes generated by reprocessing. The room in which I stood held something like one-third of the total of all the most hazardous waste produced in France since the 1960s. It was rather larger than a high school gym. I stood atop of a concrete disk with a numeric code. Beneath that disk was a cylinder of concrete perhaps 5 meters deep. Below that was 10 meters of empty space, and below that a stainless steel tube holding nuclear byproducts. After my visit to the room I was scanned for exposure to radiation. My dose? About half as much as I had absorbed on the flight from the U.S. to France, about the same amount as I’d have ingested from a small dish of mussels.

It seems a small risk to run to solve the climate problem.

The Obama administration itself in its first threat assessment back in February described climate change as the second most important danger facing the nation. If climate change is indeed so urgent and compelling, then so equally is the case for nuclear power. Fuel reprocessing enhances the safety and efficiency of the nuclear power source. For years, Democrats and liberals have been urging Americans to look to Europe for environmental solutions. Here’s one that actually works.