Microtextural investigation of hydrided α-uranium

The Hydrogen Corrosion of Uranium: Identification of Underlying Causes and Proposed Mitigation Strategies

“…Since the late 1940s, uranium hydride corrosion research has occurred in several analytical areas: 1) chemical kinetics, examining reaction rates from onset to complete destruction of the massive metal; 5,6,7,8,9,10,11,12,13 2) metallography, elucidating the connection between corrosion and metal microstructure; 14,15,16,17,18 3) surface chemical analysis, identifying the oxides and chemical impurities which potentiate or retard the corrosion reaction. 19,20,21,22,23 Whether the goal is a proactive treatment at the beginning of component life, or a remediative treatment (reconditioning) administered later in the life cycle, any mitigation or prevention strategy for hydride corrosion must first identify the critical conditions which exist at, and just prior to, the earliest stage of reaction, and then determine ways to counteract or eliminate those causative conditions.…”

Thermomechanical Response of Polycrystalline alpha-Uranium

“…This would result in a volume fraction of 2.4 x 10 4 of hydride in the polycrystal. By approximating the ⇠25 µm sized grains as cubes and assuming all of the precipitation occurs at the grain boundaries (in agreement with recent observations [60]), this could result in roughly an even coating of 10 nm thick hydride at the grain boundary. It is known that sub-micron hydrides form under the hydrogen charging conditions [61].…”

“…In a more recent study, Bingert et al [60] confirmed that hydrides form at high and low angle grain boundaries and also observed hydrides along twin interfaces. Also, it is noted that localized residual stresses develop during hydride formation due to density mismatches between the cubic (hydride) and orthorhombic (↵-uranium) phases which leads to a 70% volumetric change [56].…”

“…The formation of hydrides in ↵-uranium has been reported extensively [57,58,59,60] . The hydride formed is UH 3 , which has a simple cubic crystal structure with a lattice parameter of 6.63 Å.…”

“…The hydride formed is UH 3 , which has a simple cubic crystal structure with a lattice parameter of 6.63 Å. These hydrides are known to form at the grain boundaries even at low concentrations of hydrogen (⇠0.2 ppm) in some cases [56,60].…”