The use of electrochemical noise measurements with nuclear waste tanks

Conference · Fri Apr 01 04:00:00 EST 1994

OSTI ID:10140491

Mickalonis, J I ^[1]; Jacko, R J ^[2]; Quirk, G P; Eden, D A ^[3]

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1. Westinghouse Savannah River Co., Aiken, SC (United States)
2. Westinghouse Electric Corp., Pittsburgh, PA (United States)
3. Capcis-March Ltd., Manchester (United Kingdom)

Processing of nuclear materials for either military or civilian purposes generates waste products. The nuclear wastes are generally stored in plain carbon or stainless steel underground storage tanks. Corrosive wastes are inhibited to minimize the corrosion of these tanks and maintain tank structural integrity under normal and off-normal conditions. Storage tanks have fairly static conditions although processing of the waste in these tanks to more stable forms will produce dynamic conditions which may lead to localized corrosion. corrosion monitoring under either condition, therefore, would be advantageous for assuring that inhibitive conditions are maintained. A preliminary investigation was conducted to evaluate electrochemical noise measurements for corrosion monitoring of waste tanks. The initial results indicated that current and potential noise are correlated to the solution corrosivity. Further development is necessary to differentiate among the various forms of corrosion. Electrochemical noise measurements were made in the laboratory with plain carbon steel electrodes under simulated conditions for storage and processing of nuclear waste. Coupons were also exposed in the laboratory test vessels. The primary aggressive species of the waste was the nitrate anion, which induces pitting. The simulated waste was initially inhibited with sodium nitrite and sodium hydroxide. The nitrate concentration was increased over the test period to increase the corrosivity of the solution. The temperature was held constant at 40 C. The current and potential noise showed an increasing trend with nitrate concentrations. Under inhibited storage conditions the noise data was fairly stable. Inspection of the electrodes revealed minimal attack, especially pitting. The coupons, however, had a significant amount of pitting. This difference was attributed to the microstructure of the electrodes and coupons.

• Research Organization: Westinghouse Savannah River Co., Aiken, SC (United States)
• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC09-89SR18035
• OSTI ID: 10140491
• Report Number(s): WSRC-MS--93-373; CONF-9405117--1; ON: DE94009540
• Country of Publication: United States
• Language: English

Related Subjects

052002
12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
36 MATERIALS SCIENCE
360105
CARBON STEELS
CORROSION AND EROSION
HYDROXIDES
MONITORING
NITRITES
PITTING CORROSION
RADIOACTIVE WASTE STORAGE
RADIOACTIVE WASTES
SODIUM NITRATES
STAINLESS STEELS
TANKS
WASTE DISPOSAL AND STORAGE