Preliminary safety criteria for organic watch list tanks at the Hanford site

Webb, Alan; Stewart, Jack; Turner, O.A.; Plys, M.G.; Malinović, Borislav N.; Grigsby, J.M.; Camaioni, D.M.; Heasler, P.G.; Samuels, W.O.; Toth, James J.

doi:10.2172/449830

Cited by 26 publications

(67 citation statements)

References 3 publications

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“…The systems of interest remained those with composition typical of waste simulants as defined by Westinghouse Hanford (Meisel et al 1993). These include high concentrations (few mole/L) of hydroxide, nitrate, and nitrite, and also medium concentrations (tenth mole/L level) of organic complexants and their known degradation products (Webb et al 1995).…”

Section: Methodsmentioning

confidence: 99%

Interfacial Radiolysis Effects in Tank Waste Speciation

Orlando¹,

Meisel²,

Camaioni³

2000

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Section: Methodsmentioning

confidence: 99%

Interfacial Radiolysis Effects in Tank Waste Speciation

Orlando¹,

Meisel²,

Camaioni³

2000

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“…The original organic components in the Hanford waste tanks were sodium glycolate, citrate, HEDTA, EDTA, normal paraffinic hydrocarbons (NPH) and tributyl phosphate (Webb et al 1995). These compounds have undergone aging to more oxidized products over the years that they have been stored (Camaioni et al 1995(Camaioni et al , 1996Carlson 1997).…”

Section: General Features Of Organic Reactions In Hanford Wastesmentioning

confidence: 99%

“…These compounds have undergone aging to more oxidized products over the years that they have been stored (Camaioni et al 1995(Camaioni et al , 1996Carlson 1997). Decomposition products that have been identified include sodium ethylenediaminetriacetate (ED3A), sodium nitrilotriacetate (NTA), sodium iminodiacetate (IDA), sodium ethylenediaminediacetate (EDDA), sodium oxalate, and sodium formate (Campbell et al 1994(Campbell et al , 1995(Campbell et al , 1996.…”

Section: General Features Of Organic Reactions In Hanford Wastesmentioning

confidence: 99%

“…The thermal and radiolytic oxidation of organic compounds in simulated Hanford wastes have been studied extensively (Ashby et al 1992(Ashby et al , 1993(Ashby et al ,1994Barefield et al 1995Barefield et al , 1996Bryan et al 1993;Bryan and Pederson 1994;Camaioni et al 1995Camaioni et al ,1996Camaioni et al ,1997Delegard 1980Delegard ,1987Meisel et al 1991aMeisel et al , 1991bMeisel et al , 1992Meisel et al , 1993Meisel et al , 1997. The reactivity order for thermal degradation of the complexants, which encompasses all the pathways for the decomposition of the organic constituents in the waste in the absence of radiation, has been given as (Camaioni et al 1996):…”

Section: General Features Of Organic Reactions In Hanford Wastesmentioning

confidence: 99%

“…Additional radiolytic pathways are available for the aging of complexants and solvents in Hanford wastes (Meisel et al 1991a(Meisel et al , 1991b(Meisel et al , 1992(Meisel et al , 1993(Meisel et al ,1997Camaioni et al 1995Camaioni et al , 1996Camaioni et al , 1997. Products of water radiolysis include the hydrated electron, hydrogen atom, hydroxide radical, hydrogen dioxide radical, and hydrogen ion (Spinks and Woods 1990).…”

Section: General Features Of Organic Reactions In Hanford Wastesmentioning

confidence: 99%

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Chemical pathways for the formation of ammonia in Hanford wastes

Stock¹,

Pederson²

1997

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This report reviews chemical reactions leading to the formation of ammonia in Hanford wastes. The general features of the chemistry of the organic compounds in the Hanford wastes are briefly outlined. The radiolytic and thermal free radical reactions that are responsible for the initiation and propagation of the oxidative degradation reactions of the nitrogen-containing complexants, trisodium HEDTA and tetrasodium EDTA, are outlined. In addition, the roles played by three different ionic reaction pathways for the oxidation of the same compounds and their degradation products are described as a prelude to the discussion of the formation of ammonia. The reaction pathways postulated for its formation are based on tank observations, laboratory studies with simulated and actual wastes, and the review of the scientific literature. Ammonia derives from the reduction of nitrite ion (most important), from the conversion of organic nitrogen in the complexants and their degradation products, and from radiolytic reactions of nitrous oxide and nitrogen (least important).Reduction of nitrite ions is believed to be the most important source of ammonia. Whether by radiolytic or thermal routes, nitrite reduction reactions proceed through nitrogen dioxide, nitric oxide, the nitrosyl anion, and the hyponitrite anion. Nitrite ion is also converted into hydroxylamine, another important intermediate on the pathway to form ammonia. These reaction pathways additionally result in the formation of nitrous oxide and molecular nitrogen, whereas hydrogen formation is produced in a separate reaction sequence.The oxidative degradation of trisodium EDTA and tetrasodium HEDTA also yields ammonia and other nitrogenous gases. The complexants react with nitric oxide and nitrogen dioxide to produce oxidized compounds that subsequently undergo hydrolysis, eventually liberating ammonia. Amides and nitriles are intermediates in these long reaction sequences. , The direct reaction of hydrogen with nitrous oxide and nitrogen can account for only negligible quantities of ammonia in Hanford tanks. Thermal reactions require high temperatures (AOOOC), high pressures, and the presence of catalysts, to proceed at significant rates. Similarly, radiolytic yields for direct reactions of hydrogen with nitrogen and nitrous oxide under tank conditions are expected to be very small.Oxygen can substantially alter the yields of nitrogenous gases. Two principal pathways have been identified. Oxygen intercepts radicals produced in thermal and radiolytic reactions that would otherwise eventually result in the formation of nitrogen, nitrous oxide and ammonia. Oxygen also reacts directly with complexants and intermediates to yield oxalate ion. The hydrogen yield is often increased in the presence of oxygen.

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