Laser-based processes. Laser-based processes, which use intense, narrow-frequency radiation to cause atoms or molecules containing 235U to undergo selectively a different physical or chemical process than those containing 238U, are under intensive development in many countries, but have not yet advanced to industrial use.

The principal U. S. projects of this type are research at U. S. DOE’s Los Alamos Laboratory, which uses UF6 vapor, and work by U. S. DOE’s Livermore Laboratory and a joint venture of Avco Everett Research Laboratory, Inc., and Exxon Nuclear Company, which use uranium metal vapor. The two groups [J2, T3] using uranium metal vapor reported production of milligram quantities of partially enriched uranium in 1975. Avco and Exxon applied for a license to build a pilot plant to demonstrate their process in the mid-1980s.

Improved electromagnetic processes. Developments in plasma physics and magnet design in the 30 years since the Y-12 plant was taken off uranium isotope separation have caused many groups to reexamine electromagnetic processes for separating uranium isotopes, some of which reported at the London Conference on Uranium Isotope Separation [B20]. In the United States

a company, Phrasor, Inc., has been formed to continue development of an improved process of this general type. Dawson and associates [D3] have given a partial description of a process using ion-cyclotron resonance to ionize selectively and separate K-40. This process is being investigated for 235U with funding by U. S. DOE and TRW Defense and Space Systems.

Solvent extraction. At the 1977 International Atomic Energy Agency (IAEA) Conference on Atomic Energy at Salzburg, Austria, Commissioner Giraud of the French CEA announced development of a new process for producing uranium enriched sufficiently for reactor fuel, but impractical for producing more highly enriched weapons-grade material because it has too high a specific inventory. At the same conference, Dr. Frejacques and colleagues of the CEA [F4] said that “a new process using crown compounds of uranium is currently under study.” Such a process could involve complexing and fractional solvent extraction of 235U from an aqueous solution with a crown ether dissolved in an immiscible organic solvent.