The objective of this work is to determine optimal mixing configurations and operating conditions as well as improved sampling technology for defense waste processing facility (DWPF) waste melter feeds at US Department of Energy (DOE) sites. This report summarizes the methods used and results obtained during the progress of the study of waste slurry mixing and sampling systems during fiscal year 1977 (FY97) at the Hemispheric Center for Environmental Technology (HCET) at Florida International University (FIU). Although testing demonstrated that the concentration of fast settling solids decreased by up to 25% as the tank was emptied, batch-to-batch consistency improved as mixer jet nozzle velocity in the scaled tanks increased. Testing showed that the concentration of slow settling solids in each transfer batch was consistent over a wide range of tank operating conditions.
TANK AGITATOR DESIGN SERIES
Two geometrically scaled tanks were used with a broad spectrum of tank waste simulants to demonstrate that mixing using two rotating mixer jet pumps yields consistent slurry compositions as the tank is emptied in a series of sequential batch transfers. The tank mixing method must be able to remove settled solids from the tank more » and provide consistent feed to the WTP to facilitate waste treatment operations. The tank mixing and feed delivery must support both TOC and WTP operations. The TOCs' ability to adequately mix and sample high-level waste feed to meet the WTP WAC Data Quality Objectives must be demonstrated.
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This work represents one of the remaining technical issues with the high-level waste treatment mission at Hanford. The Hanford Tank Operations Contractor (TOC) and the Hanford Waste Treatment and Immobilization Plant (WTP) contractor are both engaged in demonstrating mixing, sampling, and transfer system capability using simulated Hanford High-Level Waste (HLW) formulations.
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This paper will discuss the history, progress, and future activities that will define and mitigate the mission risk. An evaluation of demonstration program results will identify potential mission improvement considerations that will help ensure successful mission completion. The Hanford mixing and sampling demonstration program will identify DST mixing performance capability, will evaluate representative sampling techniques, and will estimate feed batch consistency. Inconsistent feed to the WTP could cause additional batch-to-batch operational adjustments that reduce operating efficiency and have the potential to increase the overall mission length. It has been demonstrated that homogenous mixing ofHLW sludge in Hanford DSTs is not likely achievable more » with the baseline design thereby causing representative sampling and consistent feed delivery to be more difficult.
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DOE's River Protection Project (RPP) mission modeling and WTP facility modeling assume that individual 3785 cubic meter (l million gallon) HLW feed tanks are homogenously mixed, representatively sampled, and consistently delivered to the WTP. The ability to effectively mix, sample, certify, and deliver consistent batches of High Level Waste (HLW) feed from the Hanford Double Shell Tanks (DST) to the Waste Treatment and Immobilization Plant (WTP) presents a significant mission risk with potential to impact mission length and the quantity of HLW glass produced.