Article
Materials Science, Multidisciplinary
V. Klosek, M. O. J. Y. Hunault, S. Schlutig, W. Tomczak, M. Rochedy, P. L. Solari, J. Noirot
Summary: This article presents the preparation, the realization and the results of the first X-ray absorption spectroscopy analysis of a bulky irradiated UO2 sample. The study found that molybdenum in the spent fuel exists mainly in the form of two metallic phases or in solution in UO2, with detailed discussion on the nature of these dissolved species. At the cesium L3 edge, experimental difficulties were encountered, but the results indicate that cesium is likely predominantly dissolved in UO2 in both the center and periphery of the pellet.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
M. Rochedy, V. Klosek, C. Riglet-Martial, C. Onofri-Marroncle, D. Drouan, D. Reyes, P. Bienvenu, I. Roure, M. Cabie, L. Amidani, J. Lechelle, M-A. Pinault-Thaury
Summary: The study investigated the interactions of iodine and caesium in UO2. Implantation of UO2 samples followed by thermal treatment (4h at 900 degrees C or 1h at 1200 degrees C) under controlled atmosphere (0.03% H2O/H2) allowed for characterization of their structure and chemistry through various experimental techniques. Thermodynamic calculations were used to optimize the heat treatment conditions and interpret the results. The analysis of the treated samples revealed the presence of bubbles and precipitates, with CsI identified within the bubbles in agreement with the calculations. The chemical composition of the observed precipitates, likely caesium uranates, remains unclear due to the lack of experimental reference spectra.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Multidisciplinary Sciences
Gabriel L. Murphy, Robert Gericke, Sara Gilson, Elena F. Bazarkina, Andre Rossberg, Peter Kaden, Robert Thuemmler, Martina Klinkenberg, Maximilian Henkes, Philip Kegler, Volodymyr Svitlyk, Julien Marquardt, Theresa Lender, Christoph Hennig, Kristina O. Kvashnina, Nina Huittinen
Summary: In this study, researchers used electron paramagnetic resonance, high energy resolution fluorescence detection X-ray absorption near energy structure and extended X-ray absorption fine structure spectroscopic measurements to investigate the redox chemistry and mechanism of Cr-doped UO2 nuclear fuel. The results revealed the complexity of Cr states and provided valuable insights for the safe use of Cr-doped UO2 fuels for nuclear energy generation.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Amani Cheniour, Giovanni Pastore, Jason M. Harp, Christian M. Petrie, Nathan A. Capps
Summary: There is a recent push to accelerate nuclear fuel qualification by combining advanced modeling and simulation with accelerated separate effects irradiation testing. An assessment and sensitivity study was conducted on calculated fission gas release from UO2 MiniFuel disks. Qualitatively, the existing fission gas behavior model in BISON reproduces the effects of temperature and burnup as expected, but shows a less satisfactory predictive capability when compared quantitatively with FGR data from irradiated UO2 disks under thermal annealing representative of LOCA conditions.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Physics, Applied
Karl Rickert, Timothy A. Prusnick, Matthew A. Streby, David B. Turner, Charles J. Reyner, J. Matthew Mann
Summary: The study incorporates hydrothermally grown UO2 into a prototype device, using laser light for testing, and provides important data on UO2 as a neutron detector, including detection responses, resolution, and saturation behaviors.
JOURNAL OF APPLIED PHYSICS
(2021)
Article
Chemistry, Analytical
Bruce K. McNamara, Samuel Morrison, Bruce Pierson
Summary: Fluorination is used as a rapid separation technique for quantifying trace-mass, short-lived isotopes. Selective removal of volatile fluorides improves detection and quantification of select analytes, while also altering the volatility behaviors of common isotopes under low burnup conditions as compared to higher burnup metal and metal oxide fuels.
JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
(2021)
Article
Materials Science, Multidisciplinary
C. O. T. Galvin, M. J. D. Rushton, M. W. D. Cooper, D. A. Andersson, P. A. Burr, R. W. Grimes
Summary: This study used molecular dynamics and Monte Carlo simulations to predict the lowest energy shapes for voids and bubbles in UO2. It was found that low energy faceted voids are slightly more energetically favourable than spherical voids, and as Xe is added and bubble pressure increases, the faceted morphology becomes even more favourable than the spherical shape.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
G. Pastore, N. Militello, S. Blondel, B. D. Wirth
Summary: We simulated the evolution of intra-granular fission gas bubbles in UO2 using two models and compared the results to experimental data. The models showed excellent agreement with each other and with the experimental trends of bubble average size and number density. The calculated results either matched the data well or had errors within consistent uncertainties.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
E. Geiger, C. Gueneau, T. Alpettaz, C. Bonnet, S. Chatain, O. Tougait, D. Menut, S. Bellayer, M. O. J. Y. Hunault, E. C. Corcoran
Summary: The capabilities of the Thermodynamic of Advanced Fuels - International Database (TAF-ID) for reproducing the chemical behavior of irradiated nuclear fuel in severe accident conditions were studied. The study found that the thermodynamic calculations accurately simulated the solubility of fission products in the fuel matrix and the formation process of metallic phases but had limited accuracy in certain cases.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Nuclear Science & Technology
Xun Lan, Yanbo Jiang, Dan Sun, Wenbo Liu, Wenjie Li
Summary: In this study, a three-dimensional phase-field model was developed to investigate the evolution of intergranular bubbles during irradiation. The study examined the dependency of bubble percolation on bubble shape, fission rate, and average grain size. The simulation results revealed the significant effects of these factors on the shape of GB bubbles, the percolation rate, and the connectivity threshold of GB bubbles.
NUCLEAR ENGINEERING AND DESIGN
(2024)
Article
Nuclear Science & Technology
Ryutaro Tonna, Takayuki Sasaki, Yuji Kodama, Taishi Kobayashi, Daisuke Akiyama, Akira Kirishima, Nobuaki Sato, Yuta Kumagai, Ryoji Kusaka, Masayuki Watanabe
Summary: Simulated debris was synthesized under inert or oxidizing conditions using UO2, Zr, and stainless steel. The leaching behavior of fission products from the debris was evaluated using irradiation and doping methods. The dissolution behavior of U and the leaching of Cs, Sr, Ba were observed regardless of the primary solid phases, while the leaching of high-valence Eu and Ru ions was suppressed.
NUCLEAR ENGINEERING AND TECHNOLOGY
(2023)
Article
Multidisciplinary Sciences
V. L. Vinograd, A. A. Bukaemskiy, G. Deissmann, G. Modolo
Summary: Ln-doped UO2 is commonly used as a model system for studying the effects of fission and activation products on the chemical stability of spent nuclear fuel. This study compares the thermodynamics of UO2-UO3 and LnO(1.5)-UO2-UO3 systems to understand the increased resistance of Ln-doped UO2 to oxidation compared to pure UO2 in air. The findings suggest that the enhanced resistivity to oxidation in Ln-doped UO2 is likely due to a thermodynamically driven partitioning of Ln between a fluorite-type phase and a U3O8 polymorph, hindered by slow diffusion at ambient temperatures.
SCIENTIFIC REPORTS
(2023)
Article
Materials Science, Multidisciplinary
Larry K. Aagesen, Sudipta Biswas, Wen Jiang, David Andersson, Michael W. D. Cooper, Christopher Matthews
Summary: A phase-field model was developed to simulate the fission gas bubble microstructure in nuclear fuel, focusing on bubble growth in the HBS region. Simulations showed that during steady-state conditions, overpressurized bubbles decreased in pressure as they grew, but still remained above equilibrium pressure. During a LOCA transient, bubble size did not change significantly.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Floyd W. Hilty, Dong-Uk Kim, Michael R. Tonks
Summary: This study investigates the impact of fission gas bubbles on the effective thermal conductivity (ETC) of composite nuclear fuels. The results show that fission gas bubbles may completely eliminate the benefits of high thermal conductivity additives, leading to even lower thermal conductivity than fuel without additives. A trend relating the fraction of additive screened by bubbles to the ETC is identified, and a model is proposed to predict the ETC of composite fuels with fission gas bubbles for better estimation of fuel design benefits.
JOURNAL OF NUCLEAR MATERIALS
(2021)
Article
Materials Science, Multidisciplinary
Jae Joon Kim, Hyun Woo Seong, Ho Jin Ryu
Summary: The segregation of fission products and their effect on the cohesive energy of E3[110]/(111) UO2 grain boundary were analyzed using first principles calculations. The most stable segregation sites for zirconium, molybdenum, cesium, and xenon in UO2 were investigated. Molybdenum, cesium, and xenon showed segregation tendencies on the E3[110]/(111) UO2 grain boundary, while zirconium did not. The analysis of grain boundary cohesive energy revealed that zirconium and molybdenum strengthened the grain boundary cohesion, while cesium and xenon weakened it.
JOURNAL OF NUCLEAR MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Christopher N. Singh, Blas Pedro Uberuaga, Stephen J. Tobin, Xiang-Yang Liu
Summary: The relative rate of optical to thermal carrier decay is crucial for optoelectronic device performance, and radiation-induced point defects have a significant impact on this ratio. By employing a first-principles-based theory of multi-phonon emission, the thermal decay rates of six possible point defects in GaAs, a classical optoelectronic material, are evaluated. These rates reveal the propensity of electrons or holes to interact with specific defect vibrations, shedding light on the most detrimental material defects.
Article
Materials Science, Multidisciplinary
Xueyang Wu, Iman Abdallah, Wen Jiang, Robert S. Ullberg, Simon R. Phillpot, Adrien Couet, John H. Perepezko, Michael R. Tonks
Summary: An electrochemical phase-field model is used to investigate the oxidation mechanisms of the 21-2N valve stainless steel alloy exposed to carbon dioxide at 973 K. The model includes three observed oxide phases: Mn3O4, Cr2O3, and MnCr2O4. The sensitivity of oxidation processes to diffusion mobilities is examined and the oxidation rate is calibrated against experimental data. It is found that both inward oxygen and outward metal diffusion are important for oxidation, and the order of initial oxide layers impacts the diffusion of Mn.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Chemistry, Physical
Peter Hatton, Blas Pedro Uberuaga
Summary: In this study, it is found that highly disordered spinels with high concentration of antisite cation pairs still exhibit some short range order in the form of antisite chains. The formation of these chains depends on the chemistry of spinels. The effect of antisite chains on cation vacancy diffusivity varies depending on the spinel chemistry.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
Article
Materials Science, Multidisciplinary
Sylvia Koerfer, Alexander Bonkowski, Joe Kler, Peter Hatton, Blas Pedro Uberuaga, Roger A. De Souza
Summary: In this study, cation diffusion in fluorite-structured CeO2 is investigated using classical molecular dynamics and metadynamics simulations. It is found that cation diffusion primarily occurs through cation divacancies, rather than isolated vacancies or cation vacancy-oxygen vacancy associates.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Physics, Applied
R. Auguste, M. O. Liedke, M. Butterling, B. P. Uberuaga, F. A. Selim, A. Wagner, P. Hosemann
Summary: Radiation-induced property changes in materials are caused by energy transfer from incoming particles to the lattice, leading to atom displacement and the formation of extended defects. The extent of these defects depends on dose rate, material, and temperature. This study provides direct experimental evidence of non-equilibrium vacancy formation in silicon through in situ positron annihilation spectroscopy.
JOURNAL OF APPLIED PHYSICS
(2023)
Article
Materials Science, Coatings & Films
Sofia K. Pinzon, James A. Valdez, Vancho Kocevski, J. K. Baldwin, Blas P. Uberuaga, Cortney R. Kreller, Benjamin K. Derby
Summary: The study analyzes the effect of different substrate temperatures and altering the oxide cation on the structural and morphological properties of lanthanide sesquioxide thin films. It was found that the structure and morphology of the films can be controlled by manipulating deposition parameters.
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY A
(2023)
Article
Materials Science, Multidisciplinary
Christopher N. Singh, Xiang-Yang Liu, Blas Pedro Uberuaga, Stephen J. Tobin
Summary: There is growing demand for radiation-tolerant optical systems in space and nuclear applications. This study utilizes advanced modeling techniques to design radiation-hard optical materials. Molecular dynamics, density functional theory, and Maxwell's equations were used to analyze the effects of point-defects on radiation-induced attenuation in wet fused silica. Evidence is provided that non-bridging oxygen-hole centers (NBOHC) are the primary cause of attenuation in γ-irradiated optical fibers. The study also highlights the importance of spin-orbit coupling in defining the optical properties of gamma-ray induced defects.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Chemistry, Physical
Amitava Banerjee, Edward F. Holby, Aaron A. Kohnert, Shivani Srivastava, Mark Asta, Blas P. Uberuaga
Summary: This study investigates the thermodynamics and kinetics of point defects in hematite (α-Fe2O3) using density functional theory. The calculations reveal that migration barriers for point defects can vary significantly with charge state, especially for cation interstitials. Multiple possible migration pathways are found, attributed to the low symmetry of the corundum crystal structure. Additionally, the anisotropy of long-range diffusion favors diffusion along the c-axis of the crystal.
ELECTRONIC STRUCTURE
(2023)
Article
Materials Science, Multidisciplinary
Anjana Talapatra, Blas Pedro Uberuaga, Christopher Richard Stanek, Ghanshyam Pilania
Summary: The compositional and structural variety of oxide perovskites allows for a wide range of applications. Machine learning models are used to predict the band gap of perovskite compounds and identify stable and synthesizable compounds with desired band gaps.
COMMUNICATIONS MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Yang Li, Boyang Gu, Adrian Diaz, Simon R. Phillpot, David L. Mcdowell, Youping Chen
Summary: The paper presents a multiscale study of the kinetic processes of the heteroepitaxial growth of the PbSe/PbTe (111) and PbTe/PbSe(001) systems, using the Concurrent Atomistic-Continuum (CAC) method as the simulation tool. The simulations have reproduced the growth mode and layer morphology observed in experiments, and visualized the formation and evolution of dislocations.
Article
Materials Science, Multidisciplinary
Yuan Liu, An T. Ta, Shubham Pandey, Kyoung Chul Park, Shenyang Hu, Natalia B. Shustova, Simon R. Phillpot
Summary: The bonding nature of uranyl cations with Zr-MOF was investigated using density functional theory. The results revealed that the binding energy between uranyl cations and Zr-MOF depended on the specific bonding site and the degree of deprotonation in Zr-MOF. These findings are significant for the design of Zr-MOFs with efficient capture of uranyl cations.
COMPUTATIONAL MATERIALS SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Yixi Shen, Peng Wen, An T. Ta, Simon R. Phillpot, Douglas E. Spearot
Summary: In this study, we use phase-field modeling to calculate the migration velocity of intergranular He bubbles in Fe under thermal gradients. Grain boundaries with energies ranging from 0.88 to 1.6 J/m2 are considered. We address the influences of the phase-field parameterization strategy, thermal conductivity in grain boundaries, and GB diffusion coefficients on the geometry of intergranular He bubbles. Our simulations show good agreement with a theoretical model for the contact angle at the bubble/GB junction. We find that intergranular He bubbles migrate slower than He bubbles in the Fe matrix due to smaller temperature gradients at the bubble/GB junction. We observe a linear relationship between bubble migration velocity and temperature gradient for intergranular He bubbles, consistent with theoretical predictions.
JOURNAL OF NUCLEAR MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
David A. Andersson, Christopher R. Stanek, Christopher Matthews, Blas P. Uberuaga
Summary: This article introduces the motivation of new reactor concepts in studying various types of nuclear fuels. It discusses the types, properties, and historical context of the most prevalent nuclear fuels, as well as provides a perspective on the future development of nuclear fuel research. The author believes that the integration of modeling and simulation with experiments will be crucial in extracting the maximum amount of energy from existing fuels in a safe and economical way.
Article
Chemistry, Applied
Yuan Liu, An T. Ta, Kyoung Chul Park, Shenyang Hu, Natalia B. Shustova, Simon R. Phillpot
Summary: We use density functional theory to investigate the interactions of cerium, americium, and curium cations with crown ethers. Our results demonstrate that crown ethers can capture cerium, americium, and curium ions, and modifying the crown ether structure by substituting nitrogen atoms for oxygen atoms significantly increases their binding energies with radionuclides.
MICROPOROUS AND MESOPOROUS MATERIALS
(2024)
Article
Chemistry, Physical
Vancho Kocevski, Ghanshyam Pilania, Blas P. Uberuaga
Summary: Complex oxides exhibit great functionality due to their varied chemistry and structures. This study introduces a simple metric that correlates the propensity for cation disordering in perovskites, pyrochlores, and spinels with the energy to invert the cation structure. The metric provides a fast and robust way to determine the ease or difficulty of cation disordering, enabling quick screening of compounds for cation-ordering-dependent functionalities.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
