FULL-SCALE TEST OF A NON-PLUGGING BUBBLER USED IN LARGE TANKS CONTAINING HIGH YIELD STRESS SLURRIES

摘要

As a follow-up to a bench-top experiment (1), the Savannah River Technology Center (SRTC) at the Savannah River Site (SRS) carried out a full-scale test of a "large-diameter" bubbler (LDB) to measure liquid-level and density in high yield stress slurries. The test was the final step in a process to find an instrument that could effectively and economically operate in the existing mixing tank environments. Positive results would lead to implementation of the LDB. This new bubbler replaced two inadequate instruments: an expensive technology, a Holledge probe, which needed replacing twice a year and "standard bubblers", which plugged in as little as four hours of operation. Three LDBs, at different depths, were tested under highly prototypic conditions from November 27, 1996, to January 23, 1997, using the full-scale test facilities at SRS. The instruments were subjected to 58 days of slurry operation; 226 hours of which the slurry was brought to boiling temperatures. The results showed that the LDBs (6.7 cm inside diameter) operated successfully by not plugging with the glass-frit ladened slurry, which was maintained at a minimum temperature of 50°C and at ～102°C during days of boiling. A recommendation was made to implement the LDB because none of the three bubblers plugged during the test period to the point of compromising liquid-level measurement. However, after a week's operation at boiling temperatures, several inches of a soft sludge built up within the bubbler tubes. This sludge was easily removed in place with high-pressure water. Since completion of this study, four LDBs have been installed in different tanks throughout the Defense Waste Processing Facility at SRS. Their operation has been satisfactory to date.