Hypohalite oxidation in decontaminating nuclear reactors
A method is described of decontaminating metal surfaces having an inorganic coating thereon which contains radioactive substances and spinel-like chromium oxides comprising: (A) passing over the coating a decontamination solution which comprises (1) water; (2) about 0.02 to about 0.5% of a water-soluble organic acid which has an equilibrium constant in a complex with ferric ion of at least 10/sup 9/, and which is capable of producing a pH of about 2 to about 3 in water; and (3) about 0.01 to about 0.4% of a chelate in free acid form which has an equilibrium constant in a complex with ferric ion of about 10/sup 15/ to about 10/sup 17/, and which is soluble at at least 0.4% at 40/sup 0/C in water having a pH of about 2 to about 3, the chelate being selected from the group consisting of nitrilotriacetic acid, hydroxyethylenediaminetriacetic acid, and mixtures thereof; (B) passing over the coating a composition heated to about 50/sup 0/ to about 120/sup 0/C, the composition consisting essentially of (1) water; (2) about 0.1% to saturation of an alkali metal hypohalite; and (3) sufficient alkali metal hydroxide to raise the pH of the composition to at least 12; and (C) passing the decontamination solution over the coating.
- Assignee:
- Westinghouse Electric Corp., Pittsburgh, PA
- Patent Number(s):
- US 4654170
- OSTI ID:
- 6594614
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
220502* -- Nuclear Reactor Technology-- Environmental Aspects-- Radioactive Effluents
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702 -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACETIC ACID
ALKALINE EARTH METAL COMPOUNDS
ALUMINIUM COMPOUNDS
ALUMINIUM OXIDES
CARBOXYLIC ACIDS
CHALCOGENIDES
CHELATES
CHEMICAL REACTIONS
CHROMIUM COMPOUNDS
CHROMIUM OXIDES
CLEANING
COATINGS
COMPLEXES
CONTAMINATION
DECONTAMINATION
DISPERSIONS
ELEMENTS
HALIDE MINERALS
HALITE
HEATING
HYDROGEN COMPOUNDS
IRON COMPOUNDS
MAGNESIUM COMPOUNDS
MAGNESIUM OXIDES
MEDIUM TEMPERATURE
METALS
MINERALS
MIXTURES
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
OXIDATION
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
POWER REACTORS
QUANTITY RATIO
REACTORS
SOLUBILITY
SPINELS
SURFACE CONTAMINATION
TRANSITION ELEMENT COMPOUNDS
WATER