Sludge Washing and Demonstration of the DWPF Flowsheet in the SRNL Shielded Cells for Sludge Batch 6 Qualification

Abstract

Prior to initiating a new sludge batch in the Defense Waste Processing Facility (DWPF), Savannah River National Laboratory (SRNL) is required to simulate this processing, including Chemical Process Cell (CPC) simulation, waste glass fabrication, and chemical durability testing. This report documents this simulation for the next sludge batch, Sludge Batch 6 (SB6). SB6 consists of Tank 12 material that has been transferred to Tank 51 and subjected to Low Temperature Aluminum Dissolution (LTAD), Tank 4 sludge, and H-Canyon Pu solutions. Following LTAD and the Tank 4 addition, Liquid Waste Operations (LWO) provided SRNL a 3 L sample of Tank 51 sludge for SB6 qualification. Pu solution from H Canyon was also received. SB6 qualification included washing the sample per LWO plans/projections (including the addition of Pu from H Canyon), DWPF CPC simulations, waste glass fabrication (vitrification), and waste glass characterization and chemical durability evaluation.

Plutonium Solubility in High-Level Waste Alkali Borosilicate Glass

“…not volatilized). As expected, the composition of this glass was very close to the composition of the SB6 qualification glass (Pareizs, 2010). The SB6 glass with Pu did contain higher concentrations of Fe 2 O 3 , Cr 2 O 3 and NiO due to some contamination from the grinder used to prepare the PCT samples (and obviously higher PuO 2 concentration).…”

“…glass sample that was recently prepared and analyzed at SRNL (Pareizs, 2010). The SME products were calcined prior to melting to facilitate processing.…”

Washing and Demonstration of the DWPF Flowsheet in the SRNL Shielded Cells Using Post Aluminum Dissolution Tank 51 Sludge Slurry

“…Table 3-6 are the elemental compositions on a wt% calcined solids basis of the as-received Tank 51 sample and the post aluminum dissolution sample after washing (the SRAT receipt sample). The as-received Tank 51 sample is very similar to the Sludge Batch 4 qualification sample, 14 and the washed sample composition should be similar to Sludge Batch 5 with less Purex sludge contribution. This comparison shows that the aluminum dissolution process will indeed lower the aluminum contribution from the waste to the DWPF glass, but sodium content may increase due to difficulties in washing to obtain the target endpoint.…”

Desorption of Sorbates From Mst, Mmst, and CST Under Various Conditions

“…The MST concentration was based on the addition of MST from one complete SCIX batch (treatment of 1,000,000 gallons) to the average volume in Tank 51H during sludge washing. 5 The bottles were then briefly mixed by shaking, and 0-hour samples were removed. The bottles were transferred to a 25 °C shaker oven, and were shaken at a speed of 175 rpm.…”

“…The CST concentration was based on the addition of CST from one complete SCIX batch (treatment of 1,000,000 gallons) to the average volume in Tank 51H during sludge washing. 5 The remaining details are identical to the MST experiment, with the exception that samples were only submitted for ICP-MS analysis. …”