Effects of chemistry and microstructure on corrosion performance of Zircaloy-2-based BWR cladding - 2016-0066

Conference · Fri Jul 01 04:00:00 EDT 2016

DOI:https://doi.org/10.1520/STP159720160066· OSTI ID:22788422

Lin, Yang-Pi; White, David W. ^[1]; Lutz, Dan R. ^[2]

---

1. Global Nuclear Fuel-Americas, 3901 Castle Hayne Rd., Wilmington, NC 28402 (United States)
2. Global Nuclear Fuel-Americas, 6705 Vallecitos Rd., Sunol, CA 94586 (United States)

In boiling water reactors (BWRs), Zircaloy-2 is typically the material of choice for fuel cladding. With increased focus on fuel performance and reliability, consistent cladding corrosion performance under varying BWR conditions has become an acknowledged requirement for modern BWR fuel. To support optimization of corrosion performance, modifications to alloy chemistry and manufacture conditions can be made, supported by ex-reactor corrosion testing and demonstrated through in-reactor operation. In this work, the combined effects of alloy chemistry and fabrication process were investigated. The effect of alloy chemistry is often complicated by variation within a production ingot. In this work, additional measurements were intentionally taken at the tube-shell stage (before cold pilgering) so that chemistry more representative of the final cladding could be obtained and the effect of iron, nickel, and tin could be examined more closely. Although chemistry range of Zircaloy-2 was the primary focus, the effect of iron above the ASTM limit in a new alloy was also explored. Three types of cladding fabrication processes were considered. Two types included a heat treatment applied after the first cold pilgering and annealing, and the treatment was limited to the outer portion of the cladding and differed in the temperature of the heat treatment; the third type had no special heat treatments after the first cold pilgering and annealing. The weight gain of the three types of cladding with varying compositions under two corrosion test conditions (400 deg. C steam and 410/520 deg. C two-stage steam) are discussed in terms of the initial second-phase particle sizes obtained from transmission electron microscopy examinations. Based on poolside inspections and hot-cell examinations, the in-reactor corrosion performance of the two cladding types up to typical discharge exposures are discussed in the terms of corrosion margin, microstructure evolution, and correlation with ex-reactor corrosion test data. (authors)

• Research Organization: ASTM International, 100 Barr Harbor Drive, P.O. Box C700, West Conshohocken, PA, 19428-2959 (United States)
• OSTI ID: 22788422
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ANNEALING
BWR TYPE REACTORS
CLADDING
CORROSION
FABRICATION
FUELS
HOT CELLS
IRON
MICROSTRUCTURE
NICKEL
PARTICLE SIZE
REACTOR OPERATION
STEAM
TESTING
TIN
TRANSMISSION ELECTRON MICROSCOPY
ZIRCALOY 2