Pyrophoric behaviour of uranium hydride and uranium powders

Guyadec, F. Le; Genin, Xavier; Bayle, Jean-Philippe; Dugne, O.; Duhart-Barone, Anne; Ablitzer, Carine

doi:10.1016/j.jnucmat.2009.11.007

Cited by 59 publications

(33 citation statements)

References 8 publications

(11 reference statements)

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“…With continued corrosion these sites are reported to grow and ultimately coalesce, forming an encompassing film of hydride, prone to spallation as a fine pyrophoric powder [3][4][5]. The arising powder has been characterised as UH3 using X-ray photoelectron spectroscopy [6] and X-ray diffraction [3].…”

Section: Introductionmentioning

confidence: 99%

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Structural deformation of metallic uranium surrounding hydride growth sites

2015

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General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. ABSTRACTElectron backscatter diffraction (EBSD) was utilised to probe the microstructure of uranium metal in the vicinity of surface corrosion pits, resulting from hydrogen exposure (5×10 4 Pa, at 240°C).Microstructural analysis of the surface revealed a subtle increase of grain orientation variation for grains at the border of the hydride growths. Cross sectional analysis, at pit sites, revealed significant microstructure deformation in the form of crystal twinning and micro-cracking beneath the surface. These observations provide qualitative evidence that local stress intensities generated as a consequence of hydride growth and confinement, were sufficient to cause deformation within the parent metal.

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Section: Introductionmentioning

confidence: 99%

“…The arising powder has been characterised as UH3 using X-ray photoelectron spectroscopy [6] and X-ray diffraction [3].…”

Section: Introductionmentioning

confidence: 99%

Structural deformation of metallic uranium surrounding hydride growth sites

2015

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“…The formed corrosion product, uranium hydride (UH 3 ), is a highly pyrophoric and unstable substance and, therefore, classed as a potential hazard due to the potential for enhanced radionuclide release and dispersion of gas/solid fission products arising from the spent nuclear fuel (SNF) material (fire, smoke containing fission products, etc.) [4,5]. The reaction can be described by four distinct stages:…”

Section: Introductionmentioning

confidence: 99%

The effect of work-hardening and thermal annealing on the early stages of the uranium-hydrogen corrosion reaction

2018

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A B S T R A C TThe characteristics of hydride formation on metallic U at the early stages were investigated for three differently treated samples. The first sample reacted in its as-received state, the second was thermally annealed and the third sample underwent cold work-hardening prior to reaction with deuterium. From the analysis, the vacuum heat-treated sample was found to be more resilient to hydriding at the nucleation and growth stage, exhibiting a reduced number of nucleation points when compared to the as-cast uranium. The work-hardened sample was observed to be more susceptible to H 2 corrosion, displaying very dissimilar hydriding behaviour when compared to the other.

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“…Firstly, a potential safety challenge is posed by the production of pyrophoric corrosion products (uranium oxide and uranium hydride) and also by production of hydrogen gas, [2][3][4][5][6] Where H2 can be derived from corrosion of uranium and other reactive metals in the waste form. This is a proven concern as previous incidents from other facilities have been documented, albeit using different storage conditions [7][8].…”

Section: Introductionmentioning

confidence: 99%

“…corrosion of bare metal [2][3][4][10][11][12][13]. Studies of uranium corrosion in grout have found that attempts in air or a glove box to physically open the system and directly access the corrosion products can result in their vigorous exothermic chemical transformation [7].…”

Section: Introductionmentioning

confidence: 99%

Nuclear waste viewed in a new light; a synchrotron study of uranium encapsulated in grout

Stitt

Hart

Harker

et al. 2015

Journal of Hazardous Materials

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How do you characterise the contents of a sealed nuclear waste package without breaking it open? This question is important when the contained corrosion products are potentially reactive with air and radioactive. Synchrotron X-rays have been used to perform micro-scale in-situ observation and characterisation of uranium encapsulated in grout; a simulation for a typical intermediate level waste storage packet. X-ray tomography and X-ray powder diffraction generated both qualitative and quantitative data from a grout-encapsulated uranium sample before, and after, deliberately constrained H2 corrosion. Tomographic reconstructions provided a means of assessing the extent, rates and character of the corrosion reactions by comparing the relative densities between the materials and the volume of reaction products. The oxidation of uranium in grout was found to follow the anoxic U + H2O oxidation regime, and the pore network within the grout was observed to influence the growth of uranium hydride sites across the metal surface. Powder diffraction analysis identified the corrosion products as UO2 and UH3, and permitted measurement of corrosion-induced strain. Together, X-ray tomography and diffraction provide means of accurately determining the types and extent of uranium corrosion occurring, thereby offering a future tool for isolating and studying the reactions occurring in real full-scale waste package systems

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Pyrophoric behaviour of uranium hydride and uranium powders

Cited by 59 publications

References 8 publications

Structural deformation of metallic uranium surrounding hydride growth sites

Structural deformation of metallic uranium surrounding hydride growth sites

The effect of work-hardening and thermal annealing on the early stages of the uranium-hydrogen corrosion reaction

Nuclear waste viewed in a new light; a synchrotron study of uranium encapsulated in grout

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