Reduction in the onset time of breakaway oxidation on Zircaloy cladding ruptured under simulated LOCA conditions

Yamato, Masaaki; Nagase, Fumihisa; Amaya, Masaki

doi:10.1016/j.jnucmat.2013.10.044

Cited by 6 publications

(1 citation statement)

References 9 publications

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“…The grain size of the tetragonal zirconia is about 100 nm at 1373 K and only 20 nm after cooling down to room temperature [11,12]. The oxidation at high temperature causes the breakaway effect dependent on oxidation temperature and time [13][14][15][16]. For example, for the Zircaloy-4 exposed to steam and oxidized at 1273 K, the breakaway oxidation was observed after more than 1500 s in the ruptured fuel cladding and after more than 3600 s in the non-ruptured alloy [14].…”

Section: Introductionmentioning

confidence: 99%

X-Ray Computer Tomography Study of Degradation of the Zircaloy-2 Tubes Oxidized at High Temperatures

Trybuś

Olivé

Lenoir

et al. 2019

Advances in Materials Science

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The investigations of high-temperature oxidation of zirconium alloys, applied for fuel pellets in nuclear power plants, are usually limited to oxidation kinetics, phase transformations and microstructural characterization. The purpose of this research was to characterize the degradation phenomena occurring within oxide layer and at the interface oxide/metal, on internal and external Zircaloy-2 tube surfaces, below and over crystalline transformation temperature of zirconium oxides. The commercial tubes were oxidized at 1273 K and 1373 K in calm air for 30 min and then examined with a technique novel for such purpose, namely a high-resolution X-ray computer tomography. The light microscopy was used to examine the cross-surfaces. The obtained results show that the form and intensity of oxide damage is significant and it is in a complicated way related to oxidation temperature and on whether external or internal tube surface is studied. The found oxide layer damage forms include surface cracks, the detachment of oxide layers, the appearance of voids, and nodular corrosion. The oxidation effects and damage appearance are discussed taking into account the processes such as formation of oxides, their phase transformation, stress-enhanced formation and propagation of cracks, diffusion of vacancies, formation of nitrides, diffusion of hydrogen into interface oxide-metal, incubation of cracks on second phase precipitates are taken into account to explain the observed phenomena.

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