DEFINING A GLASS COMPOSITION ENVELOPE FOR AN IMPURITY VARIABILITY STUDY TO SUPPORT PLUTONIUM DISPOSITION

This study focuses on the development of a composition envelope that describes the solubility of various impurities in the lanthanide borosilicate (LaBS) glass. A series of glass compositions was selected, fabricated and characterized in order to define this envelope. The selection of glass compositions, which is the focus of this report, was based on the projected types and concentrations of impurities expected in the plutonium feed stream. A limited amount of impurity data for the various plutonium sources is available and projections were made through analysis of the available information. These projections were used to define the glass compositions to be fabricated and tested. The results of this glass selection process provided an array of glass compositions to be fabricated and characterized in the laboratory in order to evaluate the solubility of various impurity elements and their effects on crystallization and durability as measured by the Product Consistency Test (PCT). The majority of the glasses will be formulated with hafnium as a surrogate for plutonium to simplify laboratory experiments. Plutonium glass testing will also be implemented for select compositions to validate the results of the surrogate testing. The results of this variability testing will be discussed in a separate report that will provide data to validate the acceptability of the compositional envelope defined here and/or provide additional compositional constraints for the plutonium feed materials