SB3 Phase 2 Variability Study: The impact of REDOX on Durability for the FRIT 418-SB2/3 System

The objective of this report was to assess the applicability (or predictability) of the durability model and the acceptability of the resulting glasses to the Frit 418 - Sludge Batch 2/3 (SB2/3)compositional region with and without the Reduction/Oxidation (REDOX) term activated in the model. A limited test matrix was developed to supplement existing data generated by previous variability studies (SB2 and SB3 separately) within the composition region of interest. Based on the results of this study, it was demonstrated that the current model is applicable (i.e., the durability response was predicted by the model for all study glasses) to the Frit 418 - SB2/3 composition region. The results also indicate that acceptable glasses (in terms of their normalized boron release) can be produced within this compositional region. In addition, there is no evidence that the activation of the REDOX term in the Product Composition Control System (PCCS) is warranted for the Frit 418 - SB2/3 system. In fact, the data show that activation could lead to extremely conservative decisions with respect to Slurry Mix Evaporator (SME) acceptability for this frit/sludge system