Temperature-dependent axial mechanical properties of Zircaloy-4 with various hydrogen amounts and hydride orientations

• Published in: Nuclear engineering and technology 2022, 54(5), , pp.1579-1587
• Main Authors: Bang, Shinhyo, Kim, Ho-a, Noh, Jae-soo, Kim, Donguk, Keum, Kyunghwan, Lee, Youho
• Format: Article
• Language: English
• Subjects: Axial mechanical property; Dry storage; Hydride reorientation; Spent nuclear fuel; Zircaloy-4 cladding; Zirconium hydride; 원자력공학
• ISSN: 1738-5733; 2234-358X
• DOI: 10.1016/j.net.2021.11.007

The effects of hydride amount (20–850 wppm), orientation (circumferential and radial), and temperature (room temperature, 100 °C, 200 °C) on the axial mechanical properties of Zircaloy-4 cladding were comprehensively examined. The fraction of radial hydride fraction in the cladding was quantified using PROPHET, an in-house radial hydride fraction analysis code. Uniaxial tensile tests (UTTs) were conducted at various temperatures to obtain the axial mechanical properties. Hydride orientation has a limited effect on the axial mechanical behavior of hydrided Zircaloy-4 cladding. Ultimate tensile stress (UTS) and associated uniform elongation demonstrated limited sensitivity to hydride content under UTT. Statistical uncertainty of UTS was found small, supporting the deterministic approach for the load-failure analysis of hydrided Zircaloy-4 cladding. These properties notably decrease with increasing temperature in the tested range. The dependence of yield strength on hydrogen content differed from temperature to temperature. The ductility-related parameters, such as total elongation, strain energy density (SED), and offset strain decrease with increasing hydride contents. The abrupt loss of ductility in UTT was found at ∼700 wppm. Demonstrating a strong correlation between total elongation and offset strain, SED can be used as a comprehensive measure of ductility of hydrided zirconium alloy.