The Liquidus Temperature of Nuclear Waste Glasses;an International Round-Robin Study

Eight institutions from four countries participated in a round-robin study to determine the precision and bias of a liquidustemperature (TL) procedure for waste glasses being adopted by ASTM International as ASTM C 1720-11. The participantsof the round-robin study were asked to measure three different glasses with one or a combination of the following TLmeasurement methods: a gradient temperature (GT) method, a uniform temperature (UT) method, and/or a crystal fractionextrapolation (CF) method. The TL values reported by different institutions are generally consistent. The precision of TLmeasurements with each method was evaluated and is presented herein. The round-robin glasses were all previously studied atPacific Northwest National Laboratory and included ARG-1 (Glass A), Zr-9 (Glass B), and AmCm2-19 (Glass C), with measuredTL values spanning the temperature range of 960–1240°C. A precision (i.e., standard deviation) for TL has beenobtained from the data, even though the data were not acquired for all three glasses using all three methods from each participatingorganization. Also, the article provides a brief overview and the importance of the TL measurement.