Chemical Coolants for Machining Uranium in the Presence of Trace Amounts of Chloride

Sprague, Travis; Googin, J.M.; Phillips, L.

doi:10.2172/4656648

Cited by 1 publication

(5 citation statements)

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“…Further tests showed that varying pH in the range 8.4 to 12.2 had negligible effect in HPO 4 2-/PO 4 3solutions; at pH 7.2, the corrosion rates were not measurable but a light metal tarnish was observed. In contrast, the phosphate concentrations in the tests with the magnesium phosphate grouts (Delegard et al 2004) evidently were not sufficient to provide corrosion attenuation of the magnitude observed in the solution tests of Sprague et al (1964).…”

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 82%

“…A later extensive series of experiments performed to identify corrosion inhibitors for water-based cooling fluids used to machine uranium metal showed phosphates to be effective (Sprague et al 1964). The test program was specifically undertaken to discover ways to overcome uranium pitting corrosion caused by chloride ion, Cl -, which arose from handling the metal pieces and from cooling fluid breakdown.…”

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 99%

“…Besides uranium metal corrosion protection, a suitable coolant must have favorable low foaming properties, low cost, and high stability. Because none of the commercial fluids gave overall satisfactory performance, additional uranium metal corrosion tests were performed for simple aqueous solutions with and without TEA (Sprague et al 1964). The aqueous solutions tested were sodium salts of:…”

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 99%

“…The film, determined to be UO 2 and (UO 2 ) 3 (PO 4 ) 2 •4H 2 O by X-ray diffraction, was found to be self-healing such that if it was scratched, it would re-form if the specimen was again immersed in a phosphate solution even containing chloride. Sprague et al (1964) concluded:…”

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 99%

“…As noted in Section 1.3.1, commercial metal machining coolants containing 0.02 to 0.04 M nitrite (generally as sodium nitrite [NaNO 2 ]) inhibit uranium metal pitting corrosion in the presence of aerated chloride solutions much better than coolants containing no nitrite (Sprague et al 1964). Sodium nitrite at 1 g per liter (~0.0145 M) in 50/50% water/propylene glycol coolant has been used to provide corrosion resistance in machining uranium metal (Hinton et al 1986).…”

Section: Nitritementioning

confidence: 99%

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Mitigation of Hydrogen Gas Generation from the Reaction of Water with Uranium Metal in K Basins Sludge

Sinkov¹,

Delegard²,

Schmidt³

2010

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Means to decrease the rate of hydrogen gas generation from the chemical reaction of uranium metal with water were identified by surveying the technical literature. The underlying chemistry and potential side reactions were explored by conducting 61 principal experiments. Several methods achieved significant hydrogen gas generation rate mitigation. Gas-generating side reactions from interactions of organics or sludge constituents with mitigating agents were observed. Further testing is recommended to develop deeper knowledge of the underlying chemistry and to advance the technology maturation level. Uranium metal reacts with water in K Basin sludge to form uranium hydride (UH 3), uranium dioxide or uraninite (UO 2), and diatomic hydrogen (H 2). Mechanistic studies show that hydrogen radicals (H•) and UH 3 serve as intermediates in the reaction of uranium metal with water to produce H 2 and UO 2. Because H 2 is flammable, its release into the gas phase above K Basin sludge during sludge storage, processing, immobilization, shipment, and disposal is a concern to the safety of those operations. Findings from the technical literature and from experimental investigations with simple chemical systems (including uranium metal in water), in the presence of individual sludge simulant components, with complete sludge simulants, and with actual K Basin sludge are presented in this report. Based on the literature review and intermediate lab test results, sodium nitrate, sodium nitrite, Nochar Acid Bond N960, disodium hydrogen phosphate, and hexavalent uranium [U(VI)] were tested for their effects in decreasing the rate of hydrogen generation from the reaction of uranium metal with water. Nitrate and nitrite each were effective, decreasing hydrogen generation rates in actual sludge by factors of about 100 to 1000 when used at 0.5 molar (M) concentrations. Higher attenuation factors were achieved in tests with aqueous solutions alone. Nochar N960, a water sorbent, decreased hydrogen generation by no more than a factor of three while disodium phosphate increased the corrosion and hydrogen generation rates slightly. U(VI) showed some promise in attenuating hydrogen but only initial testing was completed. Uranium metal corrosion rates also were measured. Under many conditions showing high hydrogen gas attenuation, uranium metal continued to corrode at rates approaching those observed without additives. This combination of high hydrogen attenuation with relatively unabated uranium metal corrosion is significant as it provides a means to eliminate uranium metal by its corrosion in water without the accompanying hazards otherwise presented by hydrogen generation. Objectives The generation of hydrogen gas through oxidation/corrosion of uranium metal by the reaction with water can potentially create flammable gas atmospheres posing hazards in storage, processing, and disposition of the K Basin sludge. Although hydrogen generation rate reduction is desired to decrease these hazards, specific targets for reduction factors vary because of...

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Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 82%

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 99%

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 99%

Section: Phosphates and Uranium Metal Machining Coolant Fluidsmentioning

confidence: 99%

Section: Nitritementioning

confidence: 99%

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