Development of fuel-model interfaces: Characterization of Pd containing UO2 thin films

Stumpf, S.; Seibert, Α.; Gouder, T.; Huber, F.; Wiss, T.; Römer, J.; Denecke, Melissa A.

doi:10.1016/j.jnucmat.2009.11.025

Cited by 10 publications

(6 citation statements)

References 46 publications

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“…1a. The position of E 0 of the sputtered samples is shifted towards higher energy indicating the presence of a higher oxide UO 2+x which is in good accordance with the XPS results cited above [9]. The spectra of all samples are broadened and exhibit a reduced finestructure as compared to the reference spectrum.…”

Section: Uo 2 /Pdsupporting

confidence: 88%

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Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO₂matrix

Stumpf¹,

Tobias²,

Seibert³

et al. 2010

IOP Conf. Ser.: Mater. Sci. Eng.

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Abstract. The intention of the presented study is to elucidate the influence of noble metal inclusions (fission products) on the structure as well as on the electrochemical properties of spent nuclear fuel (SNF). To this aim, thin UO 2 films doped with metal inclusions such as Pd, Mo and Au are prepared by sputter deposition. The films are characterized by spectroscopic (XPS, EXAFS, XRD) as well as by microscopic (AFM, SEM) methods. In a next step the electrochemical properties of these model systems are comparatively investigated by cyclo voltammetry (CV). The sputter technique in combination with the heating treatment of the films allows the formation of a crystalline UO 2 matrix as it is found in SNF. The co-deposition with Au results in the dispersion of the pure metal in the oxide matrix. Pd as well as Mo are oxidized due to the deposition at RT. Heating the films involves a further oxidation of MoO 2 to MoO 3 . By contrast Pd agglomerates and forms metallic -phases as it is found in SNF. Electrochemical investigations of the UO 2 -Pd samples indicate an inhibiting influence of Pd on the oxidative dissolution of UO 2 . When it comes to the formation of secondary phases under reducing conditions such influence is passivated. The precipitates finally dominate the overall redox behaviour of the model system.

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Section: Uo 2 /Pdsupporting

confidence: 88%

“…A qualitative characterization of UO 2 -Pd thin films by XPS and XRD is already published by the authors [9]. The sputter co-deposition of U and Pd at room temperature (RT) in the presence of O 2 results in the homogenous distribution of Pd in a crystalline but distorted UO 2+x matrix.…”

Section: Uo 2 /Pdmentioning

confidence: 99%

Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO₂matrix

Stumpf¹,

Tobias²,

Seibert³

et al. 2010

IOP Conf. Ser.: Mater. Sci. Eng.

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“…Fuel model systems can be prepared as thin films, starting with single actinide oxides, then processing to more complex systems, doping with fission products. 9 Such model films can be prepared by reactive sputtering from a series of elemental targets. 10 Thorium is the only actinide without 5f electrons.…”

Section: Introductionmentioning

confidence: 99%

An XPS and UPS Study on the Electronic Structure of ThO_x (x ≤ 2) Thin Films

et al. 2014

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Model systems are needed for surface corrosion studies of spent nuclear oxide fuels. For this purpose ThO 2 films have been prepared in situ by adsorption of molecular and atomic oxygen on Th metal films and by sputter deposition of Th metal in an Ar/O 2 gas mixture. Surface compositions and electronic structure were compared to the bulk oxide and oxygen substoichiometry effects investigated. X-ray and ultraviolet photoemission spectroscopy (XPS and UPS, respectively) were used to measure to Th-4f, O-1s core levels and the valence band region. The Th-4f line was analyzed in terms of the final-state screening model. The evolution of the binding energies with oxygen concentration has been studied. On Th metal, adsorption of molecular oxygen ceased after the formation of a ThO 2 surface layer. In the presence of atomic oxygen, the oxidation proceeded into the underlying bulk. The formation of oxygen interstitials was shown by the broadening of the O-2p and O-1s lines and by the increase of the O-1s/Th-4f ratio. Once ThO 2 is formed, all photoemission peaks from Th and O undergo a rigid shift to low binding energy.

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“…However, these particles are either not embedded in the desired UO 2 substrate or are present in oxide form and not in the desired metallic state. Previous reports of AFM and SEM images revealing nanoparticles, 350 -850 nm in size, on UO 2 /Pd TF surfaces prepared under equivalent conditions [24] certainly involved nanoparticles, which were not metallic precipitates. As such models would be highly beneficial in systematic SNF corrosion studies to obtain a quantitative understanding of the role of -particles in suppressing radiolysis effects and activating H2 reactions associated with SNF corrosion, further effort must be invested to successfully prepare UO 2 /Mo TFs with metallic precipitates.…”

Section: Discussionmentioning

confidence: 77%

Highly resolved synchrotron-based investigations related to nuclear waste disposal

et al. 2012

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Synchrotron-based X-ray techniques are used increasingly to characterize actinide element speciation in heterogeneous media related to nuclear waste disposal safety. Especially techniques offering added temporal, spatial and energy resolved information are advancing our understanding of f-element physics and chemistry in general and of actinide element waste disposal in particular. Examples of investigations of uranium containing systems using both highly (energy) resolved X-ray emission spectroscopy (HRXES) techniques and spatially resolved techniques with focused X-ray beams are presented in this paper: polarization dependent partial fluorescence yield X-ray absorption near edge structure (PD-PFY-XANES) spectroscopic studies of a single Cs 2 UO 2 Cl 4 crystal, which experimentally reveal a splitting of the , and components of the 6d valence states [1], and characterization of UO 2 /Mo thin films prepared on different substrates using a combination of techniques (2D and 3D micro-and nano-X-ray fluorescence, XANES and both holographic and ptychographic tomography).

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Development of fuel-model interfaces: Characterization of Pd containing UO2 thin films

Cited by 10 publications

References 46 publications

Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO₂matrix

Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO₂matrix

An XPS and UPS Study on the Electronic Structure of ThO_x (x ≤ 2) Thin Films

Highly resolved synchrotron-based investigations related to nuclear waste disposal

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Development of fuel-model interfaces: Characterization of Pd containing UO2 thin films

Cited by 10 publications

References 46 publications

Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO2matrix

Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO2matrix

An XPS and UPS Study on the Electronic Structure of ThOx (x ≤ 2) Thin Films

Highly resolved synchrotron-based investigations related to nuclear waste disposal

Contact Info

Product

Resources

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Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO₂matrix

Comparative study of the structural and electrochemical properties of noble metal inclusions in a UO₂matrix

An XPS and UPS Study on the Electronic Structure of ThO_x (x ≤ 2) Thin Films