Year
1993
Abstract
The Waste Curie Monitor (WCM) is a very sensitive instrument for measuring small quantities of uranium in 208-liter (55-gal) drums or smaller waste containers. Because the sensitivity of the instrument varies dramatically for different uranium isotopes and radionuclides (e.g., 234U, 235U, and 238U), a method has been developed to measure waste containing uranium with an isotopic composition different from the isotopic composition of the calibration standards. The WCM is calibrated for 235U activity and 238U activity separately so that a calibration for any enrichment can be computed. The WCM results are also corrected for density and position of the radioactivity within the unit. A 40% full-range (reverseelectrode), high-resolution germanium (HRGe) Y~ray detector is used to determine the enrichment and to identify other isotopes, such as 232U, 137Cs, and 237Np. Labels can be generated to report the measured quantities in units of grams 235U and 238U, and in activity units of pCi/g or total nCi.