Electrochemical evaluation of nodular corrosion susceptibility of zircaloy cladding

Conference · Thu Dec 31 04:00:00 EST 1992

OSTI ID:48041

Perkins, R A ^[1]

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1. Siemens Nuclear Power Corp., Richland, WA (United States)

Several types of Zircaloy-2 and -4 cladding which have exhibited varying degrees of nodular corrosion susceptibility in autoclave tests have been examined to determine the effect of intermetallic precipitates and oxide structure on the corrosion behavior. Electrochemical testing has been performed to determine if features which may be indicative of nodular corrosion susceptibility are present. At 100{degrees}C the anodic potentiodynamic scan of a sample with a thin oxide layer (about 0.05 {mu}m) exhibits a current peak which is related to the nodular corrosion resistance of the cladding. The current peak is at about -100 mV relative to a platinum reference electrode. Late beta-quenched cladding and cladding with lower tin and higher iron to improve the nodular corrosion resistance did not exhibit the current peak. Cladding which is susceptible to nodular corrosion has the current peak. The current peak in the potentiodynamic scan provides an alternate method of evaluating nodular corrosion resistance in addition to the standard 500{degrees}C steam autoclave test. It appears to be dependent upon the electrical properties of the intermetallic precipitates which are incorporated in the thin oxide layer formed on the zircaloy. In transmission electron microscope (TEM) examination, holes have been observed in the thin oxide layers formed on the samples. The size of the holes is correlated to the intermetallic precipitates in the alloy.

• OSTI ID: 48041
• Report Number(s): CONF-910808--
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
BWR TYPE REACTORS
CORROSION
FUEL ASSEMBLIES
ZIRCALOY 2
ZIRCALOY 4