UF6 Density and Mass Flow Measurements for Enrichment Plants using Acoustic Techniques

A key enabling capability for enrichment plant safeguards being considered by theInternational Atomic Energy Agency (IAEA) is high-accuracy, noninvasive, unattendedmeasurement of UF6 gas density and mass flow rate. Acoustic techniques are currently used tononinvasively monitor gas flow in industrial applications; however, the operating pressures at gaseouscentrifuge enrichment plants (GCEPs) are roughly two orders magnitude below the capabilities ofcommercial instrumentation. Pacific Northwest National Laboratory is refining acoustic techniquesfor estimating density and mass flow rate of UF6 gas in scenarios typical of GCEPs, with the goal ofachieving 1% measurement accuracy. Proof-of-concept laboratory measurements using a surrogategas for UF6 have demonstrated signatures sensitive to gas density at low operating pressures such as10–50 Torr, which were observed over the background acoustic interference. Current efforts involvedeveloping a test bed for conducting acoustic measurements on flowing SF6 gas at representative flowrates and pressures to ascertain the viability of conducting gas flow measurements under theseconditions. Density and flow measurements will be conducted to support the evaluation. If successful,the approach could enable an unattended, noninvasive approach to measure mass flow in unit headerpipes of GCEPs.