In situ rheology and gas volume in Hanford double-shell waste tanks

Stewart, Charles W.; Alzheimer, J.M.; Brewster, M.E.; Chen, G.; Reid, Henry; Shepard, C.L.; Terrones, Guillermo; Mendoza, R.E.

doi:10.2172/414042

Cited by 43 publications

(95 citation statements)

References 19 publications

(21 reference statements)

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“…The small-scale studies on the mechanisms of gas retention and bubble behavior in tank waste have been the subject of a number of studies (see for example, Gauglitz et al 1994Gauglitz et al , 1995Gauglitz et al , 1996Gauglitz et al , 2001Gauglitz et al , 2009Stewart et al 1996;Rassat et al 1997Rassat et al , 1998Rassat et al , 1999Bredt et al 1995;Bredt and Tingey 1996;and Walker et al 1994). Gauglitz et al (2009) have recently summarized these studies.…”

Section: Previous Small-scale Studies Of Bubble Retentionmentioning

confidence: 99%

Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

Gauglitz¹,

Buchmiller²,

Probert³

et al. 2012

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Executive SummaryThe Hanford Site has 28 double-shell tanks (DSTs) and 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. The mission of the Department of Energy's River Protection Project is to retrieve and treat the Hanford tank waste for disposal and close the tank farms. A key aspect of the mission is to retrieve and transfer waste from the SSTs, which are at greater risk for leaking, into DSTs for interim storage until the waste is transferred to and treated in the Hanford Waste Treatment and Immobilization Plant. There is, however, limited space in the existing DSTs to accept waste transfers from the SSTs, and approaches to overcoming the limited DST space will benefit the overall mission.The current safety basis for managing the waste in the tank farms provides controls to prevent spontaneous buoyant-displacement gas release events (BDGREs) and provide for ongoing safe storage of the waste. The current mission plan for future waste transfers assumes a relaxed set of BDGRE controls for selected wastes and DSTs based on a new experimental finding that shows relatively low gas retention for sediment materials that are sufficiently strong (shear strengths greater than about 1000 Pa). Based on these relaxed controls, waste from additional SSTs could be retrieved and transferred to DSTs while still avoiding the potential for BDGREs.The purpose of this study is to summarize and analyze the key previous experiment that forms the basis for the relaxed controls and to summarize progress and results on new experiments focused on understanding the conditions that result in low gas retention. The previous large-scale test used about 50 m 3 of sediment, which would be unwieldy for doing multiple parametric experiments. Accordingly, experiments began with smaller-scale tests to determine whether the desired mechanisms can be studied without the difficulty of conducting very large experiments.The previous large-scale gas retention test was conducted in a 3.5 m diameter test vessel with a sediment layer about 5 m deep. The average retained-gas volume fraction grew over a 25 day period to a peak value of about 7% and then decreased to about 5%. This is much lower than in previous small-scale tests.A key objective for the current gas-retention tests is to conduct tests that have slower gas generation rates and are larger than the previous small-scale tests. In the current study, small-scale tests were conducted with various mixtures of kaolin clay and Min-U-Sil 30 ®1 , which is finely ground silica with a median diameter of about 8 microns, in primarily 12.7 cm diameter test vessels with gas generation provided either by the decomposition of hydrogen peroxide to form oxygen bubbles or by the corrosion of iron to form hydrogen bubbles. The gas generation rates varied and resulted in gas retention that peaked after about 1 to 10 days. The volumes of retained gas and total generated gas were measured over time to determine the retained-gas fraction. Tests we...

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Section: Previous Small-scale Studies Of Bubble Retentionmentioning

confidence: 99%

Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

Gauglitz¹,

Buchmiller²,

Probert³

et al. 2012

View full text Add to dashboard Cite

show abstract

“…In this application, 2 & i NaOH can be considered equivalent to water. Tingey et al (1994) reported a dynamic viscosity of 40 CP at a 400 sec-' shear rate for undiluted waste at 50 "C. Stewart (1996) reported ball rheometer viscosity behavior with an uncertainty factor of two, shown in Table 2 The viscosity results from both references for undiluted wastes at tank temperature and a 400 sed' shear rate show good agreement. When shear rate is expressed as the pipe flow velocity divided by the pipe inner radius, a 6 ft/sec flow velocity corresponds to a shear rate of about 50 sec-l.in a 3-inch ID pipe.…”

Section: Waste Viscosity Dependence On Waste Dilution and Temperaturementioning

confidence: 85%

“…When shear rate is expressed as the pipe flow velocity divided by the pipe inner radius, a 6 ft/sec flow velocity corresponds to a shear rate of about 50 sec-l.in a 3-inch ID pipe. At this shear rate, Stewart (1996) indicates an in situ waste viscosity of about 100 cP.…”

Section: Waste Viscosity Dependence On Waste Dilution and Temperaturementioning

confidence: 97%

“…The only thing that can be positively stated for tank 241-SY-101 waste is that at infinite dilution, pm = pc = 1.0 g d c c . Tingey et al (1994) and Stewart (1996) document viscosity analyses performed on tank 241-SY-101 wastes. The former investigated material from core 22 taken during Window C while the latter reported results from ball rheometer testing in tank 241-SY-101.…”

Section: Waste Viscosity Dependence On Waste Dilution and Temperaturementioning

confidence: 99%

“…For a 50 sed' shear rate, tank 241-SY-101 waste viscosities can be derived from data in Tingey et al (1994) and Stewart (1996). These are shown in Table 2 From the above table, at the specified waste transfer system operating temperature of 120 OF, the minimum specified dilution of 1 part by volume water to 2 parts by volume waste yields a slurry with an estimated viscosity of less than 30 cP.…”

Section: Table 2-2 In-situ Tank 241-sy-101 Physical Propertiesmentioning

confidence: 99%

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Process Control Plan for Tank 241-SY-101 Surface Level Rise Remediation

Estey¹

1999

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Preliminary Study of Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

Gauglitz¹,

Buchmiller²,

Probert³

et al. 2010

View full text Add to dashboard Cite

Executive SummaryThe Hanford Site has 28 double-shell tanks (DSTs) and 149 single-shell tanks (SSTs) containing radioactive wastes that are complex mixes of radioactive and chemical products. The mission of the Department of Energy's River Protection Project is to retrieve and treat the Hanford tank waste for disposal and close the tank farms. A key aspect of the mission is to retrieve and transfer waste from the SSTs, which are at greater risk for leaking, into DSTs for interim storage until the waste is transferred to and treated in the Waste Treatment and Immobilization Plant. There is, however, limited space in the existing DSTs to accept waste transfers from the SSTs, and approaches to overcoming the limited DST space will benefit the overall mission.The current safety basis for managing the waste in the tank farms provides controls to prevent spontaneous buoyant-displacement gas release events (BDGREs) and provide for ongoing safe storage of the waste. The current mission plan for future waste transfers assumes a relaxed set of BDGRE controls for selected wastes and DSTs based on a new experimental finding that shows relatively low gas retention for sediment materials that are sufficiently strong (shear strengths greater than about 1000 Pa). Based on these relaxed controls, waste from additional SSTs could be retrieved and transferred to DSTs while still avoiding the potential for BDGREs.The purpose of this study is to summarize and analyze the key previous experiment that forms the basis for the relaxed controls and to summarize initial progress and results on new experiments focused on understanding the conditions that result in low gas retention. The work is ongoing; this report provides a summary of the initial findings. The previous large-scale test used about 50 m 3 of sediment, which would be unwieldy for doing multiple parametric experiments. Accordingly, experiments will begin with smaller-scale tests to determine whether the desired mechanisms can be studied without the difficulty of conducting very large experiments.The previous large-scale gas retention test was conducted in a 3.5-m-diameter test vessel with a sediment layer about 5 m deep. The average retained-gas volume fraction grew over a 25-day period to a peak value of about 7% and then decreased to about 5%. This is much lower than in previous small-scale tests.A key objective for the current gas-retention tests is to conduct tests that have slower gas generation rates and are larger than the previous small-scale tests. In the current study, small-scale tests were conducted with various mixtures of kaolin clay and Min-U-Sil 30 ®1 , which is finely ground silica with a median diameter of about 8 microns, in 5-in. diameter test vessels with gas generation rates that resulted in peak gas retention after about 1 day. The volumes of retained gas and total generated gas were measured over time to determine the retained gas fraction. Tests were conducted in transparent vessels to allow observations of the bubbles, and the structure of retained ...

show abstract

In situ rheology and gas volume in Hanford double-shell waste tanks

Cited by 43 publications

References 19 publications

Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

Process Control Plan for Tank 241-SY-101 Surface Level Rise Remediation

Preliminary Study of Strong-Sludge Gas Retention and Release Mechanisms in Clay Simulants

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