The uranium enrichment centrifuge plant that gets the most attention these days is in Iran, but a larger one, carefully watched by the civilian nuclear power industry and its opponents, is taking shape here, in the desert just west of the Texas border. If built, it would be the largest commercial nuclear project ordered in this country in more than three decades.
To supporters, the proposed $1.3 billion plant is a sign of faith in the nuclear power industry's perseverance and revival, and a way to make reactor fuel with far less energy, replacing an enrichment technology invented for the Manhattan Project.
To opponents, it is a risky new industry that could release clouds of chemical poisons. Even if it operates accident-free, opponents say, it would produce radioactive waste that nobody knows what to do with.
New Mexico's governor, Bill Richardson, said in an interview he would support the project if there were ''an ironclad guarantee'' that the waste would leave the state. But Mr. Richardson, who was energy secretary in the Clinton administration, has expressed skepticism that the Energy Department would take the waste away, as the law requires.
The waste would leave the state -- barely, says the company that wants to build here, Louisiana Energy Services. The company's preferred disposal site is a landfill several hundred yards over the Texas border that has applied for permission to take low-level nuclear waste.
The site itself, a mile square, was determined to be well suited by Louisiana Energy's rival, which faces challenges in surviving the technology developed by Louisiana Energy.
The rival, USEC, which used to stand for the United States Enrichment Corporation, uses gaseous diffusion technology, invented for the Manhattan Project. The company, which was part of the Energy Department until it began operation as a private corporation in 1998, tried to build an enrichment system here that used lasers, but it gave up because of technical problems. Now it, too, wants to build a centrifuge plant, near a former gaseous diffusion plant in Ohio. It has a license to build a pilot plant, which it needs to persuade bankers to finance the project, but its application to license a full-scale plant is about a year behind that of Louisiana Energy Services.
The Louisiana Energy plant would duplicate centrifuge technology in use in Europe. Uranium, mixed with fluorine and heated to a gas, is spun in a metal tube at more than 1,000 revolutions per second. Uranium235, the kind that splits easily in a reactor, flows to the center, as uranium238, which is heavier, flows to the outside.
In natural uranium, the proportion of U235 is about 0.7 percent; for reactors it is raised to 3 percent to 5 percent. For weapons it is commonly pushed above 90 percent. The plant here, which would not begin to produce enriched uranium until late 2008, would be open to inspectors from the International Atomic Energy Agency, the builders say.
A critical issue in hearings here this week before the Nuclear Regulatory Commission is what would happen to the depleted uranium, from which the U235 had been removed. Louisiana Energy says it has a preliminary agreement with a nuclear services company to take the fluorine out of the mixture. The remaining uranium oxide, which is chemically nonreactive, could be buried in the Texas landfill. It could also be turned over to the Energy Department, which already has about 700,000 tons of depleted uranium, still mixed with fluorine and much of it in decaying metal canisters, in Ohio, Kentucky and Tennessee.
Two antinuclear groups -- the Nuclear Information and Resource Service, and Public Citizen -- hired a consultant, Arjun Makhijani, who asserted at the hearings that the depleted uranium had emissions similar to plutonium and that there was no proven means for safe disposal.
A Louisiana Energy Services spokesman, Marshall Cohen, said the depleted uranium was ''less radioactive than when it came out of the ground.'' Opponents say that may be so, but it is no longer in the ground, and thus a problem.