A5086233334- Nuclear Materials and Properties
- Glass properties and applications
- Nuclear materials and radiation effects
- Radioactive element chemistry and processing
- Luminescence Properties of Advanced Materials
- Nuclear reactor physics and engineering
- Fusion materials and technologies
- High-Temperature Coating Behaviors
- Advanced ceramic materials synthesis
- X-ray Diffraction in Crystallography
- Recycling and utilization of industrial and municipal waste in materials production
- High Temperature Alloys and Creep
- Intermetallics and Advanced Alloy Properties
- High-pressure geophysics and materials
- Metal and Thin Film Mechanics
- Pigment Synthesis and Properties
- Material Dynamics and Properties
- Phase-change materials and chalcogenides
- Advanced materials and composites
- Chemical Thermodynamics and Molecular Structure
- Titanium Alloys Microstructure and Properties
- Thermodynamic and Structural Properties of Metals and Alloys
- Material Science and Thermodynamics
- nanoparticles nucleation surface interactions
- Advancements in Solid Oxide Fuel Cells
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2013-2025
CEA Paris-Saclay
2019-2025
Université Paris-Saclay
2019-2025
Centre National de la Recherche Scientifique
2023
Service de Physique de l'État Condensé
2023
Imperial College London
2014-2020
CEA Paris-Saclay - Etablissement de Saclay
2020
The London College
2017
Direction des énergies
2013-2015
Transnational Press London
2014
Using molecular dynamics, the thermophysical properties of (U x ,Th1-x )O2 system have been investigated between 300 and 3600 K. The thermal dependence lattice parameter, linear expansion coefficient, enthalpy specific heat at constant pressure is explained in terms defect formation diffusivity on oxygen sublattice. Vegard's law approximately observed for solid solution below 2000 Different deviations from above this temperature occur owing to different temperatures which solutions undergo...
Abstract This study investigates the grain boundary energy dependence on segregated dopants in nanocrystalline zinc aluminate ceramics. Atomistic simulations of Σ3 and Σ9 boundaries showed that trivalent ions varying ionic radii [Sc 3+ (74.5 pm), In (80.0 Y (90.0 Nd (98.3 pm)] have a tendency to segregate both interfaces, with presenting highest segregation potentials. The connection between reduction interfacial energies was explored by measuring nanoceramics fabricated via high‐pressure...
Materials exposed to extreme radiation environments such as fusion reactors or deep spaces accumulate substantial defect populations that alter their properties and subsequently the melting behavior. The quantitative characterization requires visualization with femtosecond temporal resolution on atomic-scale length through measurements of pair correlation function. Here, we demonstrate experimentally electron diffraction at relativistic energies opens a new approach for studies kinetics. Our...
Mixed oxides of uranium and plutonium U1-yPuyO2-x are currently studied as reference fuel for Sodium-cooled Fast Reactors (SFRs). To predict the margin to melting, an accurate description both solidus liquidus temperatures these materials is crucial. In this work, after a critical review literature data, parameters liquid phase CALPHAD models Pu–O U–Pu–O systems reassessed based on model Guéneau et al.. A good agreement between calculated selected experimental data obtained. Using model,...
Displacement cascade simulations in fluorapatite show selective amorphisation, with the phosphate sub-structure forming amorphous chains interlaced much more damage-resistant calcium meta-prisms.
Some AX2 binary compounds with the fluorite structure (space group Fm3¯m ) are well-known examples of materials exhibiting transitions to ionic superconducting phases at high temperatures below their melting points. Such superionic states have been described as either highly defective crystals or part-crystal, part-liquid where A ions retain crystalline order whilst X undergo partial melting. However, no detailed description these exists. We present here results our investigation structural...
In this article first-principles DFT calculations and molecular dynamics simulations using empirical potentials have been used to study four different polymorphs of uranium dioxide that appear under high compressive tensile deformations. It has found, as expected, the ground-state structure is fluorite-type (space group $Fm\overline{3}m$). Under deformation urania transforms into cotunnite-type $Pnma$), already known experimentally. The calculated transition pressure 28 GPa in agreement with...
Recently it has been suggested that dislocations, generated by radiation damage, may increase the rate of fission gas diffusion from fuel grains, an affect which is at present not incorporated into performance codes. Therefore, we perform molecular dynamics simulations employing empirical potentials to investigate Xe atoms around edge dislocations in UO2 establish importance this pathway for release. The results suggest isolated near dislocation activation energy dramatically reduced...
Molecular dynamics simulations have been conducted to study the effects of dislocations and grain boundaries on He diffusion in . Calculations were carried out for {1 0 0}, 1 0} 1} edge dislocations, screw dislocation Σ5, Σ13, Σ19 Σ25 tilt boundaries. diffusivity as a function distance from core was investigated temperature range 2300–3000 K. An enhancement predicted within 20 Å or Further investigation showed that follows anisotropic behaviour along core, suggesting pipe occurs. Arrhenius...
The International Simple Glass (ISG) is a six-component borosilicate glass which was developed as reference for international collaborative studies on high level nuclear waste encapsulation. Its corrosion behaviour typically examined when it immersed in leaching solution, or exposed to water vapour. In this study, an alternative situation considered the only partially 7 weeks at temperature of 90 °C. case, half sample directly solution itself, and other contact with film formed by...
An unexplained discrepancy exists between the experimentally measured and theoretically calculated magnetic moments of Mn in \ensuremath{\alpha}-Fe. In this study, we use density functional theory to suggest that is likely due local strain environment a atom Fe structure. The ferromagnetic coupling, found by experiment, was shown be metastable could stabilized 2% hydrostatic compressive strain. effects concentration, vacancies, interstitial defects on moment are also discussed. It...
Cr2O3 is not only a promising functional material, but also an essential barrier to protect chromia-forming alloys against high temperature corrosion. The protecting layer grows slowly via defect-mediated diffusion. Several types of point defects could be responsible for the diffusion process depending on oxidation environment, resulting in different semiconductor characters chromia. According literature, defect chemistry antiferromagnetic (AFM) state has been well studied using density...
Ni-30Cr alloy samples were oxidized at temperatures between 500 and 900 °C to investigate the link evolution of microstructure chemical composition in substrate beneath a growing chromia layer. Before oxidation, layer ultrafine grains was observed surface thick lamellar This structure replaced by some larger recrystallized after oxidation. The growth kinetics described parabolic law with kinetic constant following an Arrhenius from 700 °C. For 800 °C, all Cr profiles showed gradient close...
Atomic scale molecular dynamics simulations of radiation damage have been performed on beryllium. Direct threshold displacement along a geodesic projection directions were used to investigate the directional dependence with high spatial resolution. It was found that directionally averaged probability increases from 0 at 35 eV, energy which there is 50% chance occurring 70 eV and asymptotically approaching 1 for higher energies. This is, however, strongly dependent varying 120 low...
This study employs molecular dynamics (MD) simulations and lattice (LD) calculations to investigate the superionic transition in ${\mathrm{UO}}_{2}$, as well characteristics of phase. The is found be a second-order phase associated with an inflection point enthalpy parameter at 2600 K. resembles displacive transitions oxygen vibration mode becoming imaginary. state shows combination different local environments dynamic features similar glass-forming liquids. analysis its reveals seemingly...