Parallel mechanism of growth of the oxide and α-Zr(O) layers on Zircaloy-4 oxidized in steam at high temperatures

Synergistic coupling of thermomechanical loading and irradiation damage in Zircaloy-4

“…To simulate stress levels sufficient to initiate channel clearing phenomena in irradiated fuel cladding, a global model is constructed with an internal pressure commensurate with high levels of burn-up [47], and is notched at the outer surface (representing a surface defect due to e.g. interfacial cracking with the oxide layer [48], hydride blistering [49], etc). Bulk isotropic elastic-plastic material properties are used in the global model.…”

Revisiting weight-gain correlations for as-fabricated Zircaloy-4 cladding tubes during steam oxidation

“…However, significant deviations from this simple situation have often been observed, specifically for the lower range of the temperature domain considered (T<1000°C). Values of the n exponent of up to 3 have been reported [NAG03,ZIN21]. Various reasons, likely strongly coupled, may explain the deviation from the parabolic regime: an increase over time (as the scale is growing) of the compressive stresses [GUE15], of the grain size (thus a decrease of the grain boundaries area) and/or of the monoclinic zirconia phase fraction [GUI19] will all result in a decrease of the oxygen mean diffusivity, leading to a n>2 exponent.…”