Considerations enabling dynamic inventory in fuel cycle facilities

Various methods of determining in-process inventory (holdup) without draindown and cleanout are presented. The uncertainties of in-process inventory measurements using a step (change in composition) in the feed of a low-enriched fabrication plant are analyzed. Propagated errors (2 sigma ) of 0.6 to 1.8% were obtained for reference assumptions. Step size and errors in concentration assays were found to have pronounced influence on holdup uncertainties. The effects of product batch size and degree of inprocess mixing, though less, were significant. Errors in weight measurements had small effects. The value of enrichment degradation was found to be about 0 for reference conditions for a plant with one metric ton holdup. The effects of step size and degree of in-process mixing on this value were significant. (auth)