Gas retention and release behavior in Hanford single-shell waste tanks

Stewart, Charles W.; Brewster, M.E.; Gauglitz, Phillip A.; Mahoney, Lenna A.; Meyer, Philip D.; Recknagle, Kurtis P.; Reid, Henry

doi:10.2172/474679

Cited by 37 publications

(72 citation statements)

References 20 publications

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“…It is apparent from the figure that the thickness of the supernatant liquid layer affects both the magnitude of the maximum retention and the mechanism of gas release (rollover or bubble disengagement). Additional, larger scale buoyant displacement tests were later performed with simulants that confirmed this assertion (Stewart et al 1996b) and led to development of a model for the minimum depth of supemate required for gas release by buoyant displacement (Meyer et al 1997;Meyer and Wells 2000).…”

Section: Gas Retention Tests In Tank 241-sy-103mentioning

confidence: 96%

Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

Hedengren¹

2000

115

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Section: Gas Retention Tests In Tank 241-sy-103mentioning

confidence: 96%

Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

Hedengren¹

2000

115

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“…are retained in Hanford HLW and simulants with shear strengths less than about 20 Pa, where p is the fluid density and g the acceleration of gravity (Stewart et al 1996). Figure I), as well as many other Hanford HLW slurries and experimental fluids ).…”

Section: Introductionmentioning

confidence: 93%

The start of ebullition in quiescent, yield-stress fluids

Sherwood¹,

Sáez

2014

Nuclear Engineering and Design

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Non-Newtonian rheology is typical for the high-level radioactive waste (HLW) slurries processed in the Hanford Tank Waste Treatment and Immobilization Plant (WTP). Hydrogen and other flammable gases are generated in the aqueous phase by radiolytic and chemical reactions. HLW slurries have a capacity for retaining gas characterized by the shear strength holding the bubbles still. The sizes and degassing characteristics of flammable gas bubbles in the HLW slurries expected to be processed by the WTP are important considerations for designing equipment and operating procedures. Slurries become increasingly susceptible to degassing as the bubble concentration increases. This susceptibility and the process of ebullitive bubble enlargement are described here. When disturbed, the fluid undergoes localized flow around neighboring bubbles which are dragged together and coalesce, producing an enlarged bubble. For the conditions considered in this work, bubble size increase is enough to displace the weight required to overcome the fluid shear strength and yield the surroundings. The buoyant bubble ascends and accumulates others within a zone of influence, enlarging by a few orders of magnitude. This process describes how the first bubbles appear on the surface of a 7 Pa shear strength fluid a few seconds after being jarred.

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“…Gas volume in parts of the tank waste can be measured directly with the gas volume fraction instrument (VFI) or the retained gas sampler (RGS) (Stewart, et al, 1996, Shekarriz, et al, 1997. These measurements can be used to calculate &/dP, which is then compared with &/dP as estimated using waste surface level, to calibrate the use of &/dP to estimate gas volume.…”

Section: Estimating Dl/dp Using Retained Gas Sampler (Rgs) Datamentioning

confidence: 99%

“…The standard relationship, which is based on ideal-gas behavior, is given as follows (see Stewart et al [1996], for example):…”

Section: Experimental Apparatus and Mdhodmentioning

confidence: 99%

Estimating retained gas volumes in the Hanford tanks using waste level measurements

Whitney¹,

Chen²,

Gauglitz³

et al. 1997

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The Hanford site is home to 177 large, underground nuclear waste storage tanks. Safety and environmental concerns surround these tanks and their contents. One such concern is the propensity for the waste in these tanks to generate and trap flammable gases. This report focuses on understanding and improving the quality of retained gas volume estimates derived fiom tank waste level measurements. While direct measurements of gas volume are available for a small number of the Hanford tanks, the increasingly wide availability of tank waste level measurements provides an opportunity for less expensive (than direct gas volume measurement) assessment of gas hazard for the Hanford tanks.Retained gas in the tank waste is inferred from level measurements --either long-term increase in the tank waste level, or fluctuations in tank waste level with atmospheric pressure changes. This report concentrates on the latter phenomena. As atmospheric pressure increases, the pressure on the gas in the tank waste increases, resulting in a level decrease (as long as the tank waste is "soft" enough). Tanks with waste levels exhibiting fluctuations inversely correlated with atmospheric pressure fluctuations were catalogued in an earlier study. Additionally, models incorporating ideal-gas law behavior and waste material properties have been proposed. These models explicitly relate the retained gas volume in the tank with the magnitude of the waste level fluctuations, &/a. This report describes how these models compare with the tank waste level measurements. Additionally, this report contains: New methodology for calculating dL/dP fiom tank waste levels -the methodology is applied to tanks with suitably available level measurements, and incorporates aspects of waste strength. The estimates are compared with previous estimates, which were based solely on the ideal gas law. Experimental work -Waste simulants containing retained gas were created, subjected to various pressure changes, and the waste levels recorded. For some experimental configurations, the behavior of the simulant tank waste was observed to be consistent with the simpler gas-law model. For waste simulants with sufficiently large shear strength, the level fluctuations were less than expected under the model. The 1eveUpressure hysteresis that is observed in some tanks' waste levels was not evident in the experiments. Work towards evaluating the uncertainty of tank gas volume estimates from direct measurements -For Tank A-101, the retained gas sampler measurements are compared with waste-level-based estimates related to retained gas volume. The two measurements compare well with each other for this tank.Comparison of dL/@ estimates fiom atmospheric pressure readings at weather stations around the Hanford site -Atmospheric pressure measurements fiom weather stations surrounding the tank farms are used to calculate dL/@ summaries like those used to evaluate tanks for flammable gas hazard. The choice of weather station has a very small effect onTank data summaries-Detailed summaries...

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Gas retention and release behavior in Hanford single-shell waste tanks

Abstract: Portions of this document may be Uegible in electronic image products. Images are produced from the best available original document.

Cited by 37 publications

References 20 publications

Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

Data Observations on Double Shell Tank (DST) Flammable Gas Watch List Tank Behavior

The start of ebullition in quiescent, yield-stress fluids

Estimating retained gas volumes in the Hanford tanks using waste level measurements

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