Compositional development of a plutonium surrogate glass without listed RCRA elements (lead and barium)

A lanthanide borosilicate (LaBS) glass composition, being evaluated by Savannah River Technology Center (SRTC) or plutonium disposition as part of the U.S. Department of Energy's (DOE) Office of the Fissile Materials Disposition (OFMD) program , has been processed with greater than 15 elemental weight percent thorium (a plutonium surrogate) without the presence of lead oxide in the glass. The glass composition is a result of several efforts to remove the lead by replacing it with strontium and sodium. The initial melts that included sodium and considerably lower aluminum resulted in visible phase separation. Two homogeneous lead free melts have been processed. The first one replaced one-fifth of the total lead with Sr on a mole percent basis. Other changes included slightly less aluminum with increases in boron and silica. The second glass composition was exactly the same as the first with an additional 1:1 replacement of barium with strontium on a mole percent basis. This last composition contains no elements considered to be hazardous as defined by the Resource and Conservation Recovery Act (RCRA elements). The Product Consistency Test (PCT) results of these two homogeneous glass composition show them to be slightly more durable than the original lanthanide borosilicate glasses (with lead) loaded with thorium