PNNL

Abstract

A key enabling capability for enrichment plant safeguards is high-accuracy, non-invasive, unattended measurement of UF6 gas density and mass flow rate. Acoustic techniques are currently used to non-invasively monitor gas flow in industrial applications; however, the operating pressures at gaseous centrifuge enrichment plants (GCEPs) are roughly two orders magnitude below the capabilities of commercial instrumentation. Pacific Northwest National Laboratory is refining acoustic techniques for estimating density and mass flow rate of UF6 gas in scenarios typical of gaseous centrifuge enrichment plants, with the goal of achieving 1% measurement uncertainty. Proof-of-concept laboratory measurements of UF6 have demonstrated signature sensitivity to gas density at pressures equivalent to 10-50 Torr of UF6, typical pressures for GCEP unit header pipes. This sensitivity was clearly observable above background acoustic interference. Current efforts involve developing a test bed for conducting acoustic measurements on flowing surrogate gas, air and SF6, at representative flow rates and pressures to ascertain the viability of conducting gas flow measurements under these conditions. Density and flow measurements will be conducted to support the evaluation. If successful, the approach could enable an unattended, non-invasive approach to measure UF6 density and mass flow in unit header pipes of GCEPs.