1. Uranium Enrichment Organization, ‡ Applied Uranium Chemistry and Spectroscopy Group, Box 2003, Oak Ridge, Tennessee 37831-7266 (D.P.A.); Oak Ridge K-25 Site, Technical Division, Box 2003, Oak Ridge, Tennessee 37831-7272 (W.D.B.); and University of Tennessee, Chemistry Department, Knoxville, Tennessee 37966-1600 (W.H.F.)