Use of In Situ Acoustic Backscatter Systems to Characterize Spent Nuclear Fuel and its Separation in a Thickener - 19288
- School of Chemical and Process Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)
- Department of Chemical Engineering, The University of Melbourne, Melbourne 3010 (Australia)
- School of Earth and Environment, University of Leeds, Leeds LS2 9JT (United Kingdom)
- School of Electronic and Electrical Engineering, University of Leeds, Leeds LS2 9JT (United Kingdom)
- CSIRO Mineral Resources, Western Precinct, Research Way, Clayton 3168 (Australia)
- Sellafield Ltd, Hinton House, Warrington WA3 6GR (United Kingdom)
To aid in the transportation, dewatering and storage of radioactive UK legacy waste sludges at Sellafield Ltd., the application of an Acoustic Backscatter System (ABS) was investigated in this study, as a method for monitoring suspended solids concentration and consolidation of cohesive and aggregated sludges (that form the basis of many wastes at Sellafield). An ABS represents a particularly promising technology, as they can be used with minimal intrusion, to measure both particle size and concentration depending on prior system knowledge, through inversion of the return echo voltage response of pulse-echo signals in the MHz range. To assess the application for continuous, high concentration (∼30 % v/v) thickened wastes, an ABS was utilised to characterise a pseudo-steady state laboratory thickener over hours, using flocculated calcite as a representative test material. Measurements were taken both horizontally through a consolidated bed using a 1 MHz transducer and vertically downwards with a 2 MHz transducer to measure sediment concentration above the settled bed and track bed height via the interface reflection. Characterisation of flocculated aggregate diameters was initially determined to be ∼510 μm, using an in-line Focussed Beam Reflectance Measurement (FBRM) device. The submerged 2 MHz probe indicated that there were only limited changes to the dispersion concentration or size over time. Changes in settled bed density, due to increasing bed height and changes in the underflow flow rate, were qualitatively measured via differences to the acoustic signal attenuation over time. An initial increase in attenuation with bed height was observed as the bed densified due to local compression. Once an equilibrium bed height was reached, the acoustic attenuation remained fairly constant with time, although the bulk underflow density was reduced with the increase in underflow rate. The solids residence time in the bed, determined from a transitive volume-balance model, was found to be ∼3200 s for pseudo-steady state operation at a maintained bed height of ∼0.175 m. Results of the study highlight the potential the ABS as a remote process monitoring tool for both relatively dilute suspensions and concentrated thickened mineral sludges, with potential applications across waste processing sites at Sellafield. (authors)
- Research Organization:
- WM Symposia, Inc., PO Box 27646, 85285-7646 Tempe, AZ (United States)
- OSTI ID:
- 23003043
- Report Number(s):
- INIS-US-21-WM-19288; TRN: US21V1159043376
- Resource Relation:
- Conference: WM2019: 45. Annual Waste Management Conference, Phoenix, AZ (United States), 3-7 Mar 2019; Other Information: Country of input: France; 34 refs.; available online at: https://www.xcdsystem.com/wmsym/2019/index.html
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ACOUSTICS
ATTENUATION
CALCITE
DENSITY
ECOLOGICAL CONCENTRATION
MHZ RANGE
PLUTONIC ROCKS
RADIOACTIVE WASTE PROCESSING
RADIOACTIVE WASTES
REFLECTION
SEDIMENTS
SLUDGES
SPENT FUELS
SUSPENSIONS
TRANSDUCERS
WATER INFLUX
WATER REMOVAL