Uranium Accountancy in Atomic Vapor Laser Isotope Separation

Year
1986
Author(s)
Riley D. Carver - Lawrence Livermore National Laboratory
Abstract
The AVLIS program pioneers the large scale industrial application of lasers to produce low cost enriched uranium fuel for light water reactors. In the process developed at Lawrence Livermore National Laboratory, normal uranium is vaporized by an electron beam, and a precisely tuned laser beam selectively photo-ionizes the uranium-235 isotopes. These ions are moved in an electromagnetic field to be condensed on the product collector. All other uranium isotopes remain uncharged and pass through the collector section to condense as tails. Tracking the three types of uranium (normal, enriched, and depleted) through the process presents special problems in accountancy. The amount of normal uranium decreases while both the enriched and depleted uranium increase. If the degree of enrichment is small, precise isotopic analyses are required to distinguish between the different types. After demonstration runs, the uranium on the collector was analyzed for isotopic content by Battelle Pacific Northwest Laboratory. Their results were checked at LLNL by analysis of parallel samples. The differences in isotopic composition as reported by the two laboratories were not significant.