Predicting Peak Hydrogen Concentrations from Spontaneous Gas Releases in Hanford Waste Tanks

Stewart, Charles W.; Hartley, Stacey A.; Meyer, Philip D.; Wells, Beric E.

doi:10.2172/15016741

Cited by 10 publications

(55 citation statements)

References 38 publications

(83 reference statements)

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“…The effect of sediment depth on shear strength is not present in small waste samples, so the actual in-tank rheology is unknown in these tanks. Available in situ shear strength measurements generally indicate increasing shear strength as a function of depth (Stewart et al 2005) consistent with this work.…”

Section: Introductionsupporting

confidence: 88%

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Characterization and Correlation of Particle-Level Interactions to the Macroscopic Rheology of Powders, Granular Slurries, and Colloidal Suspensions

Poloski¹,

Daniel²,

Rector³

et al. 2006

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Executive SummaryHanford TRU tank sludges are complex mixtures of undissolved minerals and salt solids in an aqueous phase of high ionic strength. They show complex rheological behavior resulting from interactions at the macroscopic level, such as interparticle friction between grains in the coarse fraction, as well as from interactions at the nano-scale level, such as the agglomeration of colloidal particles. An understanding of phenomena such as interparticle friction and aggregate stability under shear will allow better control of Hanford TRU tank sludges being processed for disposal.The project described in this report had two objectives. The first was to understand the physical properties and behavior of the Hanford transuranic (TRU) tank sludges under conditions that might exist during retrieval, treatment, packaging, and transportation for disposal at the Waste Isolation Pilot Plant (WIPP). The second objective was to develop a fundamental understanding of sludge physical properties by correlating the macroscopic behavior with interactions occurring at the particle/colloidal scale. These objectives were accomplished by: 1) measuring the physical and rheology properties of actual Hanford tank samples, 2) developing continuum models for coarse granular slurries, and 3) studying the behavior of colloidal agglomerates under shear and under ion irradiation.The shear strength of coarse granular powders and slurries was studied to determine ways of characterizing (quantifying) the effect of interparticle friction and cohesion on incipient motion. Additional studies were performed to develop and validate a continuum model for cohesionless granular powders and slurries undergoing three-dimensional shear. With regard to incipient motion in dense slurries, the immersion depth and containing vessel diameter significantly impact shear strength . A model accounting for the effects of interparticle friction, slurry cohesion, vane size and immersion depth, and container geometry was derived using a saturating vertical stress profile. This model was able to adequately explain experimental observations with regards to variations in container size and vane immersion depth. The functional form of the Janssen formula provides a potential scaling relationship to apply small-scale shear vane results to engineering-scale applications dealing with coarse-grained slurry systems.For granular systems undergoing three-dimensional flow, a constitutive model was developed to describe flows of cohesionless granular solids. The model is based on the postulate that the friction coefficient and the solids fraction in a moving granular material are exclusive functions of an inertial number, which represents the ratio of inertial to normal stress forces. The constitutive equation obtained has the same form as a multidimensional Bingham fluid model, albeit with an apparent viscosity and yield stress that depend on the vertical normal stress distribution. The model was applied to previously published experimental results dealing with three-dim...

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Section: Introductionsupporting

confidence: 88%

“…The retrieval processes often use water jets to mobilize the settled solids or sediment layer so that the diluted slurry can be removed from the tank. Jet penetration and sediment erosion rates will depend on the shear strength of the sediment (Stewart et al 2005). …”

Section: Introductionmentioning

confidence: 99%

Characterization and Correlation of Particle-Level Interactions to the Macroscopic Rheology of Powders, Granular Slurries, and Colloidal Suspensions

Poloski¹,

Daniel²,

Rector³

et al. 2006

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“…Gas retention and release behavior also depends on shear strength (e.g., Meacham 2010, Weber 2009, Stewart et al 2005. The relation of shear strength with elevation in the sediment can affect these dependencies.…”

Section: Shear Strength-elevation Within the Sedimentmentioning

confidence: 99%

Hanford Waste Physical and Rheological Properties: Data and Gaps

Wells¹,

Kurath²,

Mahoney³

et al. 2011

103

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Executive SummaryThe Hanford Site in Washington State manages 177 underground storage tanks containing approximately 250,000 m 3 of waste generated during past defense reprocessing and waste management operations. These tanks contain a mixture of sludge, saltcake and supernatant liquids. The insoluble sludge fraction of the waste consists of metal oxides and hydroxides and contains the bulk of many radionuclides such as the transuranic components and 90 Sr. The saltcake, generated by extensive evaporation of aqueous solutions, consists primarily of dried sodium salts. The supernates consist of concentrated (5-15 M) aqueous solutions of sodium and potassium salts. The 177 storage tanks include 149 single-shell tanks (SSTs) and 28 double-shell tanks (DSTs).Ultimately the wastes need to be retrieved from the tanks for treatment and disposal. The SSTs contain minimal amounts of liquid wastes, and the Tank Operations Contractor is continuing a program of moving solid wastes from SSTs to interim storage in the DSTs. The Hanford DST system provides the staging location for waste feed delivery to the Department of Energy (DOE) Office of River Protection's (ORP) Hanford Tank Waste Treatment and Immobilization Plant (WTP). The WTP is being designed and constructed to pretreat and then vitrify a large portion of the wastes in Hanford's 177 underground waste storage tanks.The retrieval, transport, treatment and disposal operations involve the handling of a wide range of slurries. Solids in the slurry have a wide range of particle size, density and chemical characteristics. Depending on the solids concentration the slurries may exhibit a Newtonian or a non-Newtonian rheology.The extent of knowledge of the physical and rheological properties is a key component to the success of the design and implementation of the waste processing facilities. These properties are used in engineering calculations in facility designs. Knowledge of the waste properties is also necessary for the development and fabrication of simulants that are used in testing at various scales. The expense and hazards associated with obtaining and using actual wastes dictates that simulants be used at many stages in the testing and scale-up of process equipment. The results presented in this report should be useful for estimating process and equipment performance and provide a technical basis for development of simulants for testing.The purpose of this document is to provide an updated summary of the Hanford waste characterization data pertinent to safe storage, retrieval, transport and processing operations for both the tank farms and the WTP and thereby identify gaps in understanding and data. Important waste parameters for these operations are identified by examining examples of relevant mathematical models of selected phenomena including: The data sets in (UDS composition and particle density, UDS primary particle size and shape, UDS particle size distributions [PSDs], and estimated particle size and density distributions [PSDDs]) and Poloski et al. (2007) ...

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“…Starting in 1993 and continuing to April 2000, the initially nominally 5.33-m-thick sediment layer in SY-101 (0.26 undissolved solid volume fraction) was mobilized by a mixer pump in riser 12A (renumbered to riser 015) (see Johnson et al 2000 for mixer pump, Stewart et al 2005 for waste properties). Figure 3.14 provides the riser map for SY-101.…”

Section: Sy-101mentioning

confidence: 99%

An Approach to Understanding Cohesive Slurry Settling, Mobilization, and Hydrogen Gas Retention in Pulsed Jet Mixed Vessels

Gauglitz¹,

Wells²,

Fort³

et al. 2009

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Predicting Peak Hydrogen Concentrations from Spontaneous Gas Releases in Hanford Waste Tanks

Cited by 10 publications

References 38 publications

Characterization and Correlation of Particle-Level Interactions to the Macroscopic Rheology of Powders, Granular Slurries, and Colloidal Suspensions

Characterization and Correlation of Particle-Level Interactions to the Macroscopic Rheology of Powders, Granular Slurries, and Colloidal Suspensions

Hanford Waste Physical and Rheological Properties: Data and Gaps

An Approach to Understanding Cohesive Slurry Settling, Mobilization, and Hydrogen Gas Retention in Pulsed Jet Mixed Vessels

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