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Title: FRIT DEVELOPMENT FOR HIGH LEVEL WASTE SLUDGE BATCH 5: COMPOSITIONAL TRENDS FOR VARYING ALUMINUM CONCENTRATIONS

Abstract

The objective of this study was to experimentally measure the properties and performance of a series of glasses with compositions that could represent Sludge Batch 5 (SB5) as processed at the Defense Waste Processing Facility (DWPF). The data was used to provide recommendations to the Liquid Waste Organization (LWO) regarding blending and washing strategies in preparing SB5 based on acceptability of the glass compositions. These data were also used to guide frit optimization efforts as the SB5 composition was finalized. Glass compositions for this study were developed by combining a series of SB5 composition projections with a group of frits. Three composition projections for SB5 were developed using a model-based approach at Savannah River National Laboratory (SRNL). These compositions, referred to as SB5 Cases B, C and D, projected removal of 25, 50 and 75% (respectively) of the aluminum in Tank 51 through the low temperature aluminum dissolution process. The frits for this study (Frits 530 through 537) were selected based on their predicted operating windows (i.e., ranges of waste loadings over which the predicted properties of the glasses were acceptable) and their potential (based on historical trends) to provide acceptable melt rates for SB5. Six additional glasses were designedmore » to evaluate alternatives for uranium in DWPF-type glasses used for variability studies and some scoping studies. Since special measures are necessary when working with uranium-containing glasses in the laboratory, it is desirable as a cost and time saving measure to find an alternative for uranium to support frit optimization efforts. Hafnium and neodymium were investigated as potential surrogates for uranium, and other glasses were made by simply excluding the radioactive components and renormalizing the glass composition. The study glasses were fabricated and characterized at SRNL. Chemical composition analyses suggested only minor difficulties in meeting the targeted compositions for some of the oxides for some of the glasses. Although minor differences were observed, they did not have a significant impact on the conclusions made in this study. Several of the study compositions showed retention of more than 0.5 wt% SO{sub 4}{sup 2-} in glass. Trevorite (a spinel) was the only crystalline phase that was positively identified in a few of the study glasses after the canister centerline cooled (CCC) heat treatment. Spinels are not of concern as they have been shown to have little impact on the durability of high level waste glasses. The crystallization behavior of the surrogate glasses was generally the same as that of their U{sub 3}O{sub 8}-containing counterparts. There are two pairs that were exceptions: SB5-04 (amorphous) and SB5-24 (possible trevorite), along with SB5-07 (amorphous) and SB5-25 (trevorite). In these cases, the surrogate glasses (SB5-24 and SB5-25) appear to be more conservative (more prone to crystallization) than their U{sub 3}O{sub 8}-containing counterparts. Chemical durability was quantified using the Product Consistency Test (PCT). The normalized leachate (NL) values for B, Li, Na and Si for all of the study glasses were well below those of the Environmental Assessment (EA) benchmark glass, regardless of heat treatment or compositional view. This indicates that all of the glasses had very acceptable durability performance. The highest NL [B] for the study glasses was 0.914 g/L (the quenched version of glass SB5-13), normalized using the measured, bias-correct composition. There was little practical impact of the CCC heat treatment on the PCT responses of the study glasses. The measured PCT responses were predictable by the current {Delta}G{sub p} models. In general, the PCT responses for the surrogate glasses or the glasses without U{sub 3}O{sub 8} were quite similar to their U{sub 3}O{sub 8}-containing counterparts. The average percent error in NL [B] normalized by the measured, bias-corrected compositions for the surrogate glasses compared with their radioactive counterparts was 8.8%. The largest difference in NL [B] was 0.152 g/L. While similarities existed in crystallization behavior and PCT response for both the surrogates and the glasses renormalized without U{sub 3}O{sub 8}, additional data must be collected before the best solution to fabricating test glasses without radioactive components can be identified. Further surrogate studies are currently underway at SRNL. The results of this study indicate that a frit composition can be identified that will provide a processable and durable glass when combined with SB5 at the DWPF. Additional studies are underway to recommend a frit that continues to meet process and performance requirements as well as to provide an enhanced melt rate for improved waste throughput.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
SRS
Sponsoring Org.:
USDOE
OSTI Identifier:
938430
Report Number(s):
SRNS-STI-2008-00060
TRN: US0806083
DOE Contract Number:  
DE-AC09-08SR22470
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES; 36 MATERIALS SCIENCE; ALUMINIUM; WASTE FORMS; GLASS; SLUDGES; RADIOACTIVE WASTE PROCESSING; VITRIFICATION; CHEMICAL COMPOSITION; DISSOLUTION; URANIUM OXIDES; CRYSTALLIZATION; HAFNIUM; NEODYMIUM; SIMULATION

Citation Formats

Fox, K, Tommy Edwards, David Best, Irene Reamer, and Phyllis Workman. FRIT DEVELOPMENT FOR HIGH LEVEL WASTE SLUDGE BATCH 5: COMPOSITIONAL TRENDS FOR VARYING ALUMINUM CONCENTRATIONS. United States: N. p., 2008. Web. doi:10.2172/938430.
Fox, K, Tommy Edwards, David Best, Irene Reamer, & Phyllis Workman. FRIT DEVELOPMENT FOR HIGH LEVEL WASTE SLUDGE BATCH 5: COMPOSITIONAL TRENDS FOR VARYING ALUMINUM CONCENTRATIONS. United States. doi:10.2172/938430.
Fox, K, Tommy Edwards, David Best, Irene Reamer, and Phyllis Workman. Thu . "FRIT DEVELOPMENT FOR HIGH LEVEL WASTE SLUDGE BATCH 5: COMPOSITIONAL TRENDS FOR VARYING ALUMINUM CONCENTRATIONS". United States. doi:10.2172/938430. https://www.osti.gov/servlets/purl/938430.
@article{osti_938430,
title = {FRIT DEVELOPMENT FOR HIGH LEVEL WASTE SLUDGE BATCH 5: COMPOSITIONAL TRENDS FOR VARYING ALUMINUM CONCENTRATIONS},
author = {Fox, K and Tommy Edwards and David Best and Irene Reamer and Phyllis Workman},
abstractNote = {The objective of this study was to experimentally measure the properties and performance of a series of glasses with compositions that could represent Sludge Batch 5 (SB5) as processed at the Defense Waste Processing Facility (DWPF). The data was used to provide recommendations to the Liquid Waste Organization (LWO) regarding blending and washing strategies in preparing SB5 based on acceptability of the glass compositions. These data were also used to guide frit optimization efforts as the SB5 composition was finalized. Glass compositions for this study were developed by combining a series of SB5 composition projections with a group of frits. Three composition projections for SB5 were developed using a model-based approach at Savannah River National Laboratory (SRNL). These compositions, referred to as SB5 Cases B, C and D, projected removal of 25, 50 and 75% (respectively) of the aluminum in Tank 51 through the low temperature aluminum dissolution process. The frits for this study (Frits 530 through 537) were selected based on their predicted operating windows (i.e., ranges of waste loadings over which the predicted properties of the glasses were acceptable) and their potential (based on historical trends) to provide acceptable melt rates for SB5. Six additional glasses were designed to evaluate alternatives for uranium in DWPF-type glasses used for variability studies and some scoping studies. Since special measures are necessary when working with uranium-containing glasses in the laboratory, it is desirable as a cost and time saving measure to find an alternative for uranium to support frit optimization efforts. Hafnium and neodymium were investigated as potential surrogates for uranium, and other glasses were made by simply excluding the radioactive components and renormalizing the glass composition. The study glasses were fabricated and characterized at SRNL. Chemical composition analyses suggested only minor difficulties in meeting the targeted compositions for some of the oxides for some of the glasses. Although minor differences were observed, they did not have a significant impact on the conclusions made in this study. Several of the study compositions showed retention of more than 0.5 wt% SO{sub 4}{sup 2-} in glass. Trevorite (a spinel) was the only crystalline phase that was positively identified in a few of the study glasses after the canister centerline cooled (CCC) heat treatment. Spinels are not of concern as they have been shown to have little impact on the durability of high level waste glasses. The crystallization behavior of the surrogate glasses was generally the same as that of their U{sub 3}O{sub 8}-containing counterparts. There are two pairs that were exceptions: SB5-04 (amorphous) and SB5-24 (possible trevorite), along with SB5-07 (amorphous) and SB5-25 (trevorite). In these cases, the surrogate glasses (SB5-24 and SB5-25) appear to be more conservative (more prone to crystallization) than their U{sub 3}O{sub 8}-containing counterparts. Chemical durability was quantified using the Product Consistency Test (PCT). The normalized leachate (NL) values for B, Li, Na and Si for all of the study glasses were well below those of the Environmental Assessment (EA) benchmark glass, regardless of heat treatment or compositional view. This indicates that all of the glasses had very acceptable durability performance. The highest NL [B] for the study glasses was 0.914 g/L (the quenched version of glass SB5-13), normalized using the measured, bias-correct composition. There was little practical impact of the CCC heat treatment on the PCT responses of the study glasses. The measured PCT responses were predictable by the current {Delta}G{sub p} models. In general, the PCT responses for the surrogate glasses or the glasses without U{sub 3}O{sub 8} were quite similar to their U{sub 3}O{sub 8}-containing counterparts. The average percent error in NL [B] normalized by the measured, bias-corrected compositions for the surrogate glasses compared with their radioactive counterparts was 8.8%. The largest difference in NL [B] was 0.152 g/L. While similarities existed in crystallization behavior and PCT response for both the surrogates and the glasses renormalized without U{sub 3}O{sub 8}, additional data must be collected before the best solution to fabricating test glasses without radioactive components can be identified. Further surrogate studies are currently underway at SRNL. The results of this study indicate that a frit composition can be identified that will provide a processable and durable glass when combined with SB5 at the DWPF. Additional studies are underway to recommend a frit that continues to meet process and performance requirements as well as to provide an enhanced melt rate for improved waste throughput.},
doi = {10.2172/938430},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Thu Aug 28 00:00:00 EDT 2008},
month = {Thu Aug 28 00:00:00 EDT 2008}
}

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