Rocky Flats Experience with Borosilicate Glass Rings for Criticality Control

The large scale use of borosilicate glass raschig rings for the storage of plutonium nitrate and enriched uranyl nitrate solutions began at the Rocky Flats Plant (RFP) in 1959. Much has been learned since that date in the use of these rings. Some of the problems encountered with raschig rings are (a) corrosion of rings; (b) settling of the rings; (c) chipping and cracking which have led to pump and drainage problems; (d) silicious deposits on the rings in the storage of uranium solutions; (e) plutonium oxide sludge deposits on rings; and (f) the problem of completely filling conventional domed tanks. Solutions to most of these problems have been found; however, problems (a) and (e) are receiving additional attention at RFP.