A Chemical Decontamination Process for Decontaminating and Decommissioning Nuclear Reactors

Murray, Alexander P.

doi:10.13182/nt86-a33835

Cited by 35 publications

(7 citation statements)

References 12 publications

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“…Bioavailable Fe-HBED complexes are commonly used in agriculture in Fe fertilizers to mitigate plant iron deficiency due to poor solubility of Fe-(hydr)oxide minerals at circumneutral pH, particularly in calcareous soils . Citrate, a triscarboxylate, is a low-molecular-weight organic acid that is ubiquitous in nature and present in some radioactive waste sites. , The hexadentate ligands with hard phenolate or hydroxamate Lewis base groups (HBED and DFOB) were expected to have a high affinity for U(IV) (as a hard acid), whereas ligands of lower denticity lacking the aforementioned hard Lewis base groups were expected to be less effective at chelating and mobilizing U(IV).…”

Section: Methodsmentioning

confidence: 99%

“…45 Citrate, a triscarboxylate, is a low-molecular-weight organic acid that is ubiquitous in nature and present in some radioactive waste sites. 46,47 The hexadentate ligands with hard phenolate or hydroxamate Lewis base groups (HBED and DFOB) were expected to have a high affinity for U(IV) (as a hard acid), whereas ligands of lower denticity lacking the aforementioned hard Lewis base groups were expected to be less effective at chelating and mobilizing U(IV). Mobilization experiments were conducted in an anaerobic (O 2 conc.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Ligand-Induced U Mobilization from Chemogenic Uraninite and Biogenic Noncrystalline U(IV) under Anoxic Conditions

Chardi

Satpathy

Schenkeveld

et al. 2022

Environ. Sci. Technol.

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Microbial reduction of soluble hexavalent uranium (U(VI)) to sparingly soluble tetravalent uranium (U(IV)) has been explored as an in situ strategy to immobilize U. Organic ligands might pose a potential hindrance to the success of such remediation efforts. In the current study, a set of structurally diverse organic ligands were shown to enhance the dissolution of crystalline uraninite (UO 2 ) for a wide range of ligand concentrations under anoxic conditions at pH 7.0. Comparisons were made to ligand-induced U mobilization from noncrystalline U(IV). For both U phases, aqueous U concentrations remained low in the absence of organic ligands (<25 nM for UO 2 ; 300 nM for noncrystalline U(IV)). The tested organic ligands (2,6-pyridinedicarboxylic acid (DPA), desferrioxamine B (DFOB), N , N ′-di(2-hydroxybenzyl)ethylene-diamine- N , N ′-diacetic acid (HBED), and citrate) enhanced U mobilization to varying extents. Over 45 days, the ligands mobilized only up to 0.3% of the 370 μM UO 2 , while a much larger extent of the 300 μM of biomass-bound noncrystalline U(IV) was mobilized (up to 57%) within only 2 days (>500 times more U mobilization). This work shows the potential of numerous organic ligands present in the environment to mobilize both recalcitrant and labile U forms under anoxic conditions to hazardous levels and, in doing so, undermine the stability of immobilized U(IV) sources.

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Section: Methodsmentioning

confidence: 99%

Section: ■ Materials and Methodsmentioning

confidence: 99%

Ligand-Induced U Mobilization from Chemogenic Uraninite and Biogenic Noncrystalline U(IV) under Anoxic Conditions

Chardi

Satpathy

Schenkeveld

et al. 2022

Environ. Sci. Technol.

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“…34 In this reagent, the cerium is also present as cerric ion, but the concentration of Ce(IV) is much lower than in other Ce(IV)-containing decontamination solutions.…”

Section: Iiia2 Commercial Productsmentioning

confidence: 95%

Decontamination of FAST (CPP-666) fuel storage area stainless steel fuel storage racks

Kessinger¹

1993

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“…The main goal of these studies has been to investigate the chemical reactivity of the decontamination reagents with the contaminant films (Bradbury ef al. 1983;Murray 1986). In contrast to earlier radioactive tracer studies, a solid scintillation technique will enable us to continuously evaluate the interface between the substrate and the contaminant during the decontamination process.…”

Section: The Use Of Radiotracers In Cleaning Studiesmentioning

confidence: 99%

A Noninvasive Study of Milk Cleaning Processes: Calcium Phosphate Removal

Grant

Webb

Jeon

1997

J Food Process Engineering

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High temperature, high pH milk processing results in the formation of mineral rich deposits that are > 70% mineral and < 30% protein by weight. This research investigates the removal of P32 labeled mixtures of calcium phosphate dihydrate (brushite, CaHPO4–2H2O) and hydroxyapatite (Ca5(PO4)3OH) from stainless steel tubes using a solid scintillation technique. Experiments were performed at pH values ranging from 2.86–7.82 and flow rates from 3.8–11.4 L/min. Previous cleaning models are reviewed and a mass transfer model is proposed which, when compared to the experimental results suggests that film removal is due to both dissolution and mechanical effects due to shear stress. A modified first order model is presented which incorporates the effects of the solvent flow rate and pH on decontamination rates. This first order model is in agreement with the experimental results over the range of pH and flow rates investigated.

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A Chemical Decontamination Process for Decontaminating and Decommissioning Nuclear Reactors

Cited by 35 publications

References 12 publications

Ligand-Induced U Mobilization from Chemogenic Uraninite and Biogenic Noncrystalline U(IV) under Anoxic Conditions

Ligand-Induced U Mobilization from Chemogenic Uraninite and Biogenic Noncrystalline U(IV) under Anoxic Conditions

Decontamination of FAST (CPP-666) fuel storage area stainless steel fuel storage racks

A Noninvasive Study of Milk Cleaning Processes: Calcium Phosphate Removal

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