Y. Nishino et al., FORMATION AND DISSOLUTION OF OXIDE FILM ON ZIRCONIUM ALLOYS IN 288-DEGREES-C PURE WATER UNDER GAMMA-RAY IRRADIATION, Journal of nuclear materials, 248, 1997, pp. 292-298
Citations number
19
Categorie Soggetti
Nuclear Sciences & Tecnology","Mining & Mineral Processing","Material Science
Laboratory corrosion tests for zirconium alloys which were based on Zi
rcaloy-2 were performed in 288 degrees C oxygenated pure water for 100
days both with and without Co-60 gamma-ray irradiation. No nodular ox
ide was observed. Corrosion weight gains of the alloy which had the lo
west nodular corrosion resistance were lower for the irradiated condit
ion than the non-irradiated condition. On the other hand, the alloys w
hich had higher nodular corrosion resistances showed almost the same w
eight gains for both conditions. Differences of weight gain with and w
ithout irradiation were attributed to dissolution of the oxide film in
the high temperature water. Dissolution tests of single crystal yttri
a-doped ZrO2 indicated that 30-40% larger amounts dissolved into water
under the gamma-ray irradiation. Low angle incident X-ray diffraction
analysis showed that the tetragonal-ZrO2 fraction in the oxide film w
as lower with irradiation than without it, especially for the near sur
face area. The water radiolysis species accelerated the dissolution of
the oxide film, especially film on the alloy with lower nodular corro
sion resistance. This dissolution led to the lower tetragonal-ZrO2 fra
ction and was considered to be one of the factors causing a localized
breakdown of the barrier oxide film to make the nodular oxide. (C) 199
7 Elsevier Science B.V.