Cutting back on uranium enrichment.

Cutting back on uranium enrichment

The Department of Energy (DOE) is getting out the mothballs for two uranium enrichment plants. One plant, which dates back to World War II, will go "on standby,' while another, only partly completed and representing the latest generation of enrichment technology, will be abandoned. Last week, DOE also decided to concentrate its future research and development effort on a laser technique for enriching uranium.

"Our strategy is aimed at achieving a competitive price structure and developing the world's most advanced uranium enrichment technology,' says Secretary of Energy John S. Herrington.

These decisions were prompted by a sharp decline in the worldwide market for enriched uranium. Not only are fewer nuclear power plants being built, but stronger competition from European suppliers using newer, more energyefficient technologies is also cutting into the U.S. share of the international market (SN: 1/28/84, p. 59). A decade ago, the United States was the sole supplier in the noncommunist world.

Currently, three U.S. plants, all more than 30 years old, produce enriched uranium using a "gaseous diffusion' process. In this process, uranium hexafluoride gas passes through a series of filters. Molecules containing the lighter isotope uranium-235 diffuse slightly more quickly than those containing U-238. However, these gaseous diffusion plants are inefficient and are now running at well below capacity. By shutting down its plant in Oak Ridge, Tenn., DOE expects to save about $50 million a year.

After spending about $2.6 billion, DOE is also stopping work on its giant "gas centrifuge enrichment plant' near Portsmouth, Ohio (SN: 8/7/82, p. 86). In this technology, tall, cylindrical centrifuges spin uranium hexafluoride gas, separating the different uranium isotope-containing molecules like cream from milk.

With 1,170 centrifuges already installed in the first of two processing buildings, the gas centrifuge plant is partly finished. Earlier this year, Goodyear Atomic Corp., which runs the plant for DOE, began testing the centrifuges and produced the first enriched samples. However, completing the plant could cost an additional $5 billion. According to DOE studies, such a plant would not be economical without a more advanced type of centrifuge.

But now DOE has decided to devote its entire uranium enrichment research effort to "atomic vapor laser isotope separation' (AVLIS), with no funding for work on the advanced gas centrifuge. In the laser enrichment process, an intense, finely tuned laser beam focused on a stream of atomic uranium vapor forces the ejection of electrons from U-235 atoms but not from U-238 atoms. The ionized atoms are then collected (SN: 5/15/82, p. 327).

AVLIS survived a very intensive peer review, says James I. Davis, who heads the project at the Lawrence Livermore (Calif.) National Laboratory. "It was the nearest thing to a technical court that we have,' he says.

"AVLIS is the way of the future, the uranium enrichment technology of the 21st century,' says Herrington. "It has the technical and economic potential for better performance than the [advanced gas centrifuge].'

Nevertheless, Rep. Marilyn Lloyd (D-Tenn.) says DOE should continue to fund the advanced gas centrifuge program as a backup, although at a considerably reduced level. Later this month, Lloyd's congressional subcommittee will consider this and other questions related to DOE's uranium enrichment program.

Davis says that a large-scale, prototype laser enrichment system may be in operation by 1988. "There's no question that the process will perform,' he says. "It's a question of how well it'll perform.

"We're pretty optimistic right now that we'll be able to proceed,' adds Davis, "if there's enough funding.' So far, a little less than $400 million has been spent on the AVLIS program.