Thermal and Radiolytic Gas Generation Tests on Material from Tanks 241-U-103, 241-AW-101, 241-S-106, and 241-S-102: Status Report

King, Cathleen; Bryan, Samuel A.

doi:10.2172/7831

Cited by 9 publications

(18 citation statements)

References 4 publications

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“…The reaction mechanism can be temperature sensitive, similar to the 3.5 temperature sensitivity for the flammable gas-producing reaction between glycolate and nitrate/nitrite (Barefield 1995(Barefield , 1996 PNNL and the Georgia Institute of Technology investigated gas production from Hanford wastes. Bryan and coworkers investigated thermal and radiolytic gas production from Hanford tank wastes Bryan and King 1998;King and Bryan 1999;King et al 1997;Pederson and Bryan 1996;Bryan and Pederson 1995). The Georgia Institute of Technology team investigated mechanisms for gas production from Hanford 241-SY tank wastes (Ashby et al 1994;Barefield et al 1995Barefield et al , 1996.…”

Section: Literature Review On Flammable Gas Production By Organic/nitmentioning

confidence: 99%

Thermal Flammable Gas Production from Bulk Vitrification Feed

Scheele¹,

McNamara²,

Bagaasen³

2008

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SummaryThe baseline bulk-vitrification (BV) process (also known as in-container vitrification ICV™) includes a mixer/dryer to convert liquid low-activity waste (LAW) into a dried, blended feed for vitrification. Feed preparation includes blending LAW with glass-forming minerals (GFMs) and cellulose and drying the mixture to a suitable dryness, consistency, and particle size for transport to the ICV TM container. The cellulose is to be added to the BV feed at a rate sufficient to destroy 75% of the nitrogen present as nitrate or nitrite based on Smith et al.'s (1999) Concern exists that flammable gases may be produced during drying operations at levels that could pose a risk. The drying process is conducted under vacuum in the temperature range of 60 to 80°C. These flammable gases could be produced either through thermal decomposition of cellulose or waste organics or as a by-product of the reaction of cellulose and/or waste organics with nitrate or the postulated small amount of nitrite present in the waste.To help address the concern about flammable gas production during drying, Pacific Northwest National Laboratory (PNNL) performed studies to identify the gases produced at dryer temperatures and at possible process upset conditions. These studies combined simultaneous thermogravimetric and differential thermal analysis (TG/DTA) with Fourier transform infrared spectroscopy (TG/DTA/FTIR) of gases evolved up to 525°C and isothermal studies up to 120°C with mass spectrometry (MS) analysis of evolved gases to determine flammable gas production from the cellulose and organic constituents in simulated BV feed.In the TG/DTA/FTIR studies, we investigated the effects of water and the amount of stoichiometric cellulose added on the evolved gases from simulated S-109 BV feed containing both cellulose and acetate (chosen as the representative waste organic). Water was tested at 4 and 12 wt%. Cellulose was tested at 75 and 100% of the Smith et al. postulated stoichiometry (C:N ratios of 0.75:1 and 1.0:1.0, respectively).In the TG/DTA/FTIR studies, we found that added water (free water) evolved by 120°C well before any TG/DTA/FTIR-detected reactions between cellulose and nitrate and/or nitrite began. The BV feed did not produce any flammable hydrocarbon gases such as methane or ethane at concentrations sufficient to be observed by FTIR. FTIR cannot see hydrogen or other symmetrical molecules such as nitrogen or oxygen. Based on the FTIR evolved gas analyses, the reaction between nitrate and/or nitrite with cellulose qualitatively produces CO 2 , N 2 O, NO, and NO 2 . Water was not observed, although it was expected based on Equation S-1. The presence of NO and NO 2 in trace quantities indicates that secondary reactions are occurring; the FTIR analyses were not quantitative.In the isothermal studies, we investigated the effects of temperature, initial water content, cellulose presence, and waste organics as acetate presence. We tested simulated S-109 BV feed with cellulose and without acetate at room temperature (22°C), 80 ...

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Section: Literature Review On Flammable Gas Production By Organic/nitmentioning

confidence: 99%

Thermal Flammable Gas Production from Bulk Vitrification Feed

Scheele¹,

McNamara²,

Bagaasen³

2008

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“…Gas generation tests on actual waste samples have provided a better estimate of the gas composition in this tank . Gas compositions based on generation rates extrapolated to in-tank conditions are also given for AW-IO1 (King and Bryan 1999) and AN-105 (Person 1998) for comparison with RGS results (see Section 6.3 for details).…”

Section: -2mentioning

confidence: 99%

“…Two sets of gas generation rate measurements were conducted with samples of convective layer material from AW-101 (King and Bryan 1999). The first set used temperatures of 60, 90, and 120 "C with external irradiation of 37,000 R/h following basically the same procedure as used for SY-103 above.…”

Section: Tank 241-aw-101 Gas Generation Testsmentioning

confidence: 99%

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

Hedengren¹

2000

115

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“…Ammonia was usually detected in these samples but is not included here because a total NH3 generation rate could not be measured accurately with the gas manifold system. Table 2.8 is a summary of generation rates and concentrations from the experiments (King and Bryan 1999). (a) Based on tank waste mass, temperature, and dose rate.…”

Section: Waste Sample Gas Composition Derived From Laboratory Testsmentioning

confidence: 99%