Effect of pH on Hydrogen Pick-Up and Corrosion in Zircaloy-4

Abstract

MUZIC-2 was the second phase of a large international collaboration between industry and academic institutions seeking to understand the fundamental mechanisms behind aqueous corrosion and hydrogen pick-up of the zirconium alloys used for fuel cladding in Light Water Reactors. The collaboration was led by Westinghouse, and the industrial partners were: the

Mechanism of the α-Zr to hexagonal-ZrO transformation and its impact on the corrosion performance of nuclear Zr alloys

“…The suboxide on the 105-day Zr-0.5Nb, right side of the map in Fig.2(b), and the 540-day Zr-1Nb alloy, Fig.2(c) and Fig.6, shows a smoother or plate-shaped morphology. Most of the previous APT/TEM/EELS results report Widmanstatten-type suboxides[16,17,23,37,[71][72][73][74][75][76], but plate-like morphologies have been found in a few cases, Figure3-49 in [71] and Figure 4.51 in [72] for example. The obvious questions are what controls these differences in suboxide grain morphology, what possible transformation mechanisms are involved in the transformation sequence α-Zr→h-ZrO→ZrO2, and what is the possible impact of these different morphologies on the overall corrosion behavior?…”