Preliminary PCT data on glass formulations developed for Hanford Site low-level wastes

Tank wastes stored at the Hanford Site are to be separated into high-level and low-level waste (LLW) fractions and vitrified for disposal. The high content of Na{sub 2}O in the LLW, averaging about 80 wt% on an oxide basis, necessitates the development of durable high-sodium glasses. Pacific Northwest Laboratory (PNL) is providing glass formulations for the LLW vitrification program. The most important considerations for acceptable LLW waste glass compositions are the following: (1) the capability to incorporate high sodium content from LLW; (2) satisfactory long-term durability; and (3) proper processability, such as desired viscosity at melting temperature. To develop durable high-sodium glasses in a reasonably short time and to supply data needed for modeling the glass`s long-term performance, several short-term test methods, such as 7-day PCT (Product Consistency Test), 28-day Materials Characterization Center MCC-1 test, single-pass flow through test, and vapor-hydration test have been used. A long-term static test (up to one year using PCT) is also being performed for selected glasses. This data report includes only the PCT data available at the time of the publication.