Comparison of the long-time corrosion behavior of certain Zr alloys in PWR, BWR, and laboratory tests
- Siemens AG, Erlangen (Germany). Power Generation Group
- Siemens Power Corp., Richland, WA (United States). Nuclear Div.
Laboratory corrosion tests have always been an important tool for Zr alloy development and optimization. However, it must be known whether a test is representative for the application in-reactor. To shed more light on this question, coupons of several Zr alloys were exposed under isothermal conditions in BWR and PWR type environments. For evaluation of the in-PWR tests and for comparison of out-of-pile and in-pile tests, the different temperatures and times were normalized to a temperature-independent normalized time by assuming an activation temperature (Q/R) of 14,200 K. Comparison of in-PWR and out-of-pile corrosion behavior of Zircaloy shows that corrosion deviates to higher values in PWR if a weight gain of about 50 mg/dm{sup 2} is exceeded. In the case of the Zr2.5Nb alloy, a slight deviation of corrosion as compared to laboratory results starts in PWR only above a weight gain of 100 mg/dm{sup 2}. In BWR, corrosion of Zircaloy is enhanced early in time if compared with out-of-pile. Zr2.5Nb exhibits higher corrosion results in BWR than Zircaloy-4. Alloying chemistry and material condition affect corrosion of Zr alloys. However, several of the material parameters have shown a different ranking in the different environments. Nevertheless, several material parameters influencing in-reactor corrosion like the second phase particle (SPP) size of in-PWR behavior as the Sn and Fe content can be optimized by out-of-pile corrosion tests.
- OSTI ID:
- 479467
- Report Number(s):
- CONF-950926--
- Country of Publication:
- United States
- Language:
- English
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