Decontamination of metal surfaces in nuclear power reactors

Patent · Tue May 06 00:00:00 EDT 1986

OSTI ID:5770910

Murray, A P; Weisberg, S L; Becker, Jr, L F

A method is described of decontaminating metal surfaces coated with oxides containing radioactive substances which consists of: (A) providing a decontamination solution which comprises (1) water; (2) about 0.02 to about 0.5% of at least one 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 2 to 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 19/, 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; (B) heating the decontamination solution to about 70/sup 0/ to about 200/sup 0/C; (C) circulating the decontamination solution over he metal surfaces and through a cation exchange resin until until the radioactivity of the decontamination solution does not increase significantly after contacting the metal surfaces; (D) providing an oxidizing solution which comprises (1) water; (2) 0.2 to 2.5% of an alkali metal permanganate; and (3) about 0.2 to about 2.5% of an alkali metal hydroxide; (E) heating the oxidizing solution to about 70/sup 0/ to about 200/sup 0/C; (F) circulating the oxidizing solution over the metal surfaces until the dichromate level in the oxidizing solution ceases to increase significantly; and (G) circulating the decontamination solution over the metal surfaces and through a cation exchange resin until the radioactivity of the decontamination solution does not increase significantly after contacting the metal surfaces.

• Assignee: Westinghouse Electric Corp., Pittsburgh, PA
• Patent Number(s): US 4587043
• OSTI ID: 5770910
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
220502* -- Nuclear Reactor Technology-- Environmental Aspects-- Radioactive Effluents
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400702 -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ALKALI METAL COMPOUNDS
CATIONS
CHARGED PARTICLES
CLEANING
CONTAMINATION
DECONTAMINATION
ELEMENTS
EQUILIBRIUM
HEATING
HIGH TEMPERATURE
HYDROGEN COMPOUNDS
ION EXCHANGE
IONS
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC POLYMERS
OXIDIZERS
OXYGEN COMPOUNDS
PETROCHEMICALS
PETROLEUM PRODUCTS
PH VALUE
POLYMERS
POWER REACTORS
QUANTITY RATIO
REACTORS
RESINS
SOLUBILITY
SURFACE CONTAMINATION
SURFACE TREATMENTS
WATER