Synthesis and characterization of nanometric powders of UO2+x, (Th,U)O2+x and (La,U)O2+x

Rousseau, G.; Fattahi, Massoud; Grambow, Bernd; Desgranges, Lionel; Boucher, Florent; Ouvrard, G.; Millot, Nadine; Niepce, J.-C.

doi:10.1016/j.jssc.2009.06.039

Cited by 29 publications

(11 citation statements)

References 21 publications

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“…In the case of oxidic An IV colloids, such colloids are often regarded as amorphous An IV oxyhydroxide nanoparticles. However, a closer look into these “amorphous” oxyhydroxides by high‐resolution transmission electron microscopy (HR‐TEM) has revealed that these colloids are composed of nanocrystalline domains of the fluorite‐analog uraninite type ( Fm

\overset{3}{true}

m) which also refers to the oxyhydroxide of Zr IV , a chemical analog of An IV . These An IV oligomers and clusters are dissolvable in aqueous solutions as waterborne colloids, which also exhibit the Fm

\overset{3}{true}

m structure .…”

Section: Introductionmentioning

confidence: 99%

Oxyhydroxy Silicate Colloids: A New Type of Waterborne Actinide(IV) Colloids

et al. 2016

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At the near‐neutral and reducing aquatic conditions expected in undisturbed ore deposits or in closed nuclear waste repositories, the actinides Th, U, Np, and Pu are primarily tetravalent. These tetravalent actinides (AnIV) are sparingly soluble in aquatic systems and, hence, are often assumed to be immobile. However, AnIV could become mobile if they occur as colloids. This review focuses on a new type of AnIV colloids, oxyhydroxy silicate colloids. We herein discuss the chemical characteristics of these colloids and the potential implication for their environmental behavior. The binary oxyhydroxy silicate colloids of AnIV could be potentially more mobile as a waterborne species than the well‐known mono‐component oxyhydroxide colloids.

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\overset{3}{true}

\overset{3}{true}

m structure .…”

Section: Introductionmentioning

confidence: 99%

Oxyhydroxy Silicate Colloids: A New Type of Waterborne Actinide(IV) Colloids

et al. 2016

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“…from 90 Th to 94 Pu, 8 except for 91 Pa which shows a strong oxidation tendency to form Pa(V). 9 Considerable efforts by precedent researchers have yielded success in identifying the fluorite-based oxide NCs originating from aqueous solutions of Th(IV), 10 U(IV), 11 and Pu(IV), 1,6,12 whilst no report has yet been released for Np(IV) NCs despite the longstanding prognostication of their formation. 13,14 We herein report the first characterisation of nano-sized neptunium dioxide (NpO 2 ) obtained by a novel approach based on the dilution of an aqueous bicarbonate solution of Np(IV).…”

mentioning

confidence: 99%

Intrinsic formation of nanocrystalline neptunium dioxide under neutral aqueous conditions relevant to deep geological repositories

et al. 2015

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The dilution of aqueous neptunium carbonate complexes induces the intrinsic formation of nanocrystalline neptunium dioxide (NpO2) particles, which are characterised by UV/Vis and X-ray absorption spectroscopies and transmission electron microscopy. This new route of nanocrystalline NpO2 formation could be a potential scenario for the environmental transport of radionuclides from the waste repository (i.e. under near-field alkaline conditions) to the geological environment (i.e. under far-field neutral conditions).

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“…Recently, Rousseau et al presented a wet chemical novel method to synthesize UO 2 (and also UO 2 doped with tetra-or trivalent elements), based on the electrochemical reduction of U 6+ to U 4+ , followed by a precipitation in a reducing and anoxic condition, at constant pH [29]. The mother U 4+ solution was made dissolving UNH in 1 M NaCl.…”

Section: Electrochemically Assisted Synthesesmentioning

confidence: 99%

Uranium Dioxide Nanoparticulated Materials

Soldati¹,

Lago²,

Prado³

2021

Nuclear Materials

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Nanostructured actinide materials have gained the attention of the nuclear community after the discovery of enhanced properties in fuels that undergo high burn up. On these conditions, the UO 2 grains experimented recrystallization and formed a new rim of UO 2 nanoparticles, called high burn up structures (HBS). The pellets with HBS showed closed porosity with better fission gas retention and radiation tolerance, ameliorated mechanical properties, and less detriment of the thermal conductivity upon use. In this chapter, we will review different ways to obtain uranium nanoparticles, with emphasis on their synthesis and characterization. On the one hand, we will comment on radiation chemical syntheses, organic precursor-assisted syntheses, denitration processes, and biologically mediated syntheses. On the other hand, we will include for each of them a reference to the appropriate tools of the materials science that are used to fully characterize physical and chemical properties of these actinide nanoparticles.

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Synthesis and characterization of nanometric powders of UO2+x, (Th,U)O2+x and (La,U)O2+x

Cited by 29 publications

References 21 publications

Oxyhydroxy Silicate Colloids: A New Type of Waterborne Actinide(IV) Colloids

Oxyhydroxy Silicate Colloids: A New Type of Waterborne Actinide(IV) Colloids

Intrinsic formation of nanocrystalline neptunium dioxide under neutral aqueous conditions relevant to deep geological repositories

Uranium Dioxide Nanoparticulated Materials

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