PEROXIDE-INHIBITED DECONTAMINATION SOLUTIONS FOR CARBON STEEL AND OTHER METALS IN THE GAS-COOLED REACTOR PROGRAM. Progress Report, November 1959-July 1962

Technical Report · Tue Jan 01 04:00:00 EST 1963

DOI:https://doi.org/10.2172/4734095· OSTI ID:4734095

Meservey, A. B.

A search for solutions suitable for dissolving uranium dioxide powder or lumps and yet noncorrosive enough to be used for decontaminating the carbon steel EGCR charge and service machines resulted in the development of buffered oxalate solutions of controlled temperature and pH, with hydrogen peroxide added to act as corrosion inhibitor, UO/sub 2/ oxidizer, and decontamination aid. Hydrogen peroxide acts either as a corrosion promoter or inhibitor, depending on factors such as its concentration, the ratio to other ingredients, acidity, temperature, the presence of complexing agents, and the ferric ion content of the solution. In general, oxalate-peroxide solutions for fission product decontamination from metal surfaces were superior to more conventional decontaminating solutions and had attractively low corrosion rates on carbon steel (less than 0.01 mil/hr), Solution instability, initially a serious drawback, was largely overcome. Of nearly a hundred formulations studied, the one having the best combination of long life, low corrosivity, high solvency for UO/sub 2/, decontamination power, safety, and ease of waste disposal was an aqueous solution of 0.4M oxalic acid, 0.18M ammonium citrate, and 0.34M H/sub 2/O/sub 2/, adjusted to pH 4.00 with ammonium hydroxide and used at 85 to 95 deg C. Similar solutions at lower pH, with increased H/sub 2/O/sub 2/ concentration to maintain noncorrosiveness, were successful decontaminants at 60 deg C when contact times were increased to several hours. Contaminated stainless steels heated to 500 deg C in helium resisted decontamination in noncorrosive reagents. Oxalate-peroxide soluttons are currently recommended as UO/sub 2/ solvents and as general decontaminants for mild steel and aluminum surfaces in the GCR program, and for stainless steels which were not strongly heated while contaminated. These solutions may also find application in the decontamination of metals used in the aqueous reprocessing of radioactive nuclear fuels. (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-17-008247
• OSTI ID: 4734095
• Report Number(s): ORNL-3308
• Country of Publication: United States
• Language: English

Related Subjects

ACCIDENTS
ACIDITY
ALUMINUM
AMMONIUM COMPOUNDS
BIBLIOGRAPHY
CARBON STEELS
CHEMISTRY
CITRIC ACID
COMPLEXES
CONTROL SYSTEMS
COOLANT LOOPS
CORROSION PROTECTION
DECONTAMINATION
EFFICIENCY
EGCR
ENVIRONMENT
FAILURES
FISSION PRODUCTS
GAS COOLANT
HELIUM
HYDROGEN PEROXIDES
HYDROXIDES
MATERIALS TESTING
MECHANICAL STRUCTURES
METALS
OPERATION
OXALATES
OXALIC ACID
PERSONNEL
POPULATIONS
POWDERS
REACTOR CORE
REACTOR SAFETY
REACTORS
REPORT
REPROCESSING
SAFETY
SHUTDOWN
SOLUTIONS
STAINLESS STEELS
SURFACES
TEMPERATURE
URANIUM DIOXIDE
WATER