Automated Holdup Measurement System at the Ulba Metallurgical Plant

Holdup—the residual material that accumulates in process equipment, pipes, valves, ductwork, vacuum lines, ventilation systems, air filters, etc., at a manufacturing plant where special nuclear material is processed—can constitute a substantial part of “material unaccounted for” (MUF) if not measured. Measuring holdup can present a considerable challenge for international safeguards at facilities with a large throughput such as the Ulba Metallurgical Plant (UMP), which processes large quantities of low-enriched uranium to produce ceramic fuel pellets for nuclearpowered reactors. To address this challenge, the UMP, the U.S. Department of Energy, the International Atomic Energy Agency, and U.S. national laboratories have focused their cooperative efforts on establishing a fast, automated holdup-measurement system. Such a novel system, based on a generalized-geometry-holdup gamma-ray assay technique using HMS4 software was implemented in May 2007 at the UMP. In this paper, we present a description of the implemented automated holdup-measurement system and the preliminary data from holdup measurements. In addition, the estimated impact of the implemented system on the operations at the UMP will be discussed.