查看更多>>摘要：Delayed hydride cracking (DHC) remains an important phenomenon when considering cladding mechanical integrity during transport and storage of spent nuclear fuel. This work studies the hydrogen diffusion and precipitation patterns during DHC as a function of temperature via high-resolution neutron imaging. Zircaloy-2 cladding tubes with and without an inner liner were radially cracked from the outside-in direction within a temperature range of 210-360 & DEG;C. A quantitative analysis was performed on the neutron radiographs showing the average radial concentration of hydrogen around the crack tip. The results show the trend of an increase in local concentration of hydrogen precipitated around the crack tip with an in-crease in cracking temperature. The elevated local concentrations correlate with the amount of hydrogen in solid solution available to diffuse towards the crack tip as well as the tensile stresses at the crack tip.(C) 2022 The Authors. Published by Elsevier B.V.& nbsp;
查看更多>>摘要：Ni-WC cemented carbides has a series of excellent properties, such as mechanical properties, thermal stability and wear resistance, but its corrosion resistance in molten fluoride salt is unknown. In this work, the corrosion behaviors of a Ni-WC cemented carbide (86.7W-8C-5Ni-0.3Cr wt.%) in molten FLiNaK salt (LiF-NaF-KF: 46.5-11.5-42 mol.%) and salt vapor were investigated by static immersion tests at 700 C. The microstructure and phase composition of the material after corrosion were characterized by scanning electron microscopy (SEM), electron probe micro-analysis (EPMA) and scanning transmission electron microscopy with energy dispersive spectrometry (STEM/EDS). The results show that in the liquid salt, Ni-rich particles are deposited on the material surface, and Cr from the binder of the specimens is dissolved. The oxidative impurities in the salt vapor induce the formation of flaky Cr2O3 on the material surface. The relatively little corrosion in both salt and vapor indicates that the application of this material in molten fluoride salts environment is promising. (c) 2022 Elsevier B.V. All rights reserved.
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