NSUF - Nuclear Science User Facilities

Clarissa Yablinsky

Profile Information
Name
Clarissa Yablinsky
Institution
Los Alamos National Laboratory
Position
Scientist
h-Index
ORCID
0000-0001-6162-0949
Publications:
"Fission Products in Nuclear Fuel: Comparison of Simulated Distribution with Correlative Characterization Techniques" Anter EL-AZAB, Jian Gan, Billy Valderrama, Clarissa Yablinsky, Microscopy and Microanalysis Vol. 19 2013 968-969 Link
During the fission process in a nuclear reactor, uranium dioxide (UO2) fuel material is irradiated, forming fission products (FPs). The addition of FPs alters the path phonons travel in UO2, detrimentally altering the thermal conductivity of the fuel. [1] To improve fuel performance, a fundamental understanding of the role of insoluble FPs, such as Xenon (Xe), during microstructural evolution is critical. Correlative characterization techniques where atom probe tomography (APT) is paired with transmission electron microscopy (TEM) can provide unique insights into the segregation behavior of FPs. Coupling these techniques with computer simulations of fission product distribution provide deeper understanding of FP migration during service. Although there are limitations with each of these techniques in isolation, significant insight into material behavior can be gained with the concurrent and synergistic pairing of multiple experimental and computational techniques.
"In-Situ TEM Observation of Dislocation Evolution in Kr-Irradiated UO2 Single Crystal" Todd Allen, Jian Gan, Mahima Gupta, Janne Pakarinen, Clarissa Yablinsky, Marquis Kirk, Xianming Bai, Journal of Nuclear Materials Vol. 443 2013 71-77 Link
In situ transmission electron microscopy (TEM) observation of UO2 single crystal irradiated with Kr ions at high temperatures was conducted to understand the dislocation evolution due to high-energy radiation. The dislocation evolution in UO2 single crystal is shown to occur as nucleation and growth of dislocation loops at low-irradiation doses, followed by transformation to extended dislocation segments and networks at high doses, as well as shrinkage and annihilation of some loops and dislocations due to high temperature annealing. Generally the trends of dislocation evolution in UO2 were similar under Kr irradiation at different ion energies and temperatures (150 keV at 600 °C and 1 MeV at 800 °C) used in this work. Interstitial-type dislocation loops with Burgers vector along 〈1 1 0〉 were observed in the Kr-irradiated UO2. The irradiated specimens were denuded of dislocation loops near the surface.
"Investigation of material property influenced stoichiometric deviations as evidenced during UV laser-assisted atom probe tomography in fluorite oxides" Todd Allen, Jian Gan, Hunter Henderson, Michele Manuel, Billy Valderrama, Clarissa Yablinsky, Nuclear Instruments and Methods in Physics Research B: Beam Interactions with Materials and Atoms Vol. 359 2015 107-114 Link
Oxide materials are used in numerous applications such as thermal barrier coatings, nuclear fuels, and electrical conductors and sensors, all applications where nanometer-scale stoichiometric changes can affect functional properties. Atom probe tomography can be used to characterize the precise chemical distribution of individual species and spatially quantify the oxygen to metal ratio at the nanometer scale. However, atom probe analysis of oxides can be accompanied by measurement artifacts caused by laser-material interactions. In this investigation, two technologically relevant oxide materials with the same crystal structure and an anion to cation ratio of 2.00, pure cerium oxide (CeO2) and uranium oxide (UO2) are studied. It was determined that electronic structure, optical properties, heat transfer properties, and oxide stability strongly affect their evaporation behavior, thus altering their measured stoichiometry, with thermal conductance and thermodynamic stability being strong factors.
"Study of Interfacial Interactions Using Thin Film Surface Modification" Alexander Mairov, Kumar Sridharan, Clarissa Yablinsky, Transactions of the American Nuclear Society Vol. 106 2012 1270 Link
Interfaces play a key role in dictating the long-term stability of materials under the influence of radiation and high temperatures. For example, grain boundaries affect corrosion by way of providing kinetically favorable paths for elemental diffusion, but they can also act as sinks for defects and helium, generated during irradiation. Likewise, the stability of nanometer scale(Y, Ti)-oxide particles in nano-structured oxide dispersion strengthened(ODS) steels depends strongly on the stoichiometric and physical stability of the oxide particles/matrix interface under radiation and high temperatures[1]. A fundamental understanding of these interfacial effects is crucially important to the development of materials for extreme environments of a nuclear reactor. Research in the last three decades has shown that energetic ion beams can be powerful tools to modify near surface structure of materials[2]. For example, with heavy ions …
"Transmission Electron Microscopy Investigation of Krypton Bubbles in Polycrystalline CeO2" Todd Allen, Jian Gan, Mahima Gupta, Clarissa Yablinsky, Marquis Kirk, Nuclear Technology Vol. 182 2013 164-169 Link
To gain an understanding of gas bubble transport in oxide nuclear fuel, this paper uses polycrystalline CeO2, composed of both nanograins and micrograins, as a surrogate material for UO2. The CeO2 was implanted with 150-keV Kr ions up to a dose of 1 × 1016 ions/cm2 at 600°C. Transmission electron microscopy characterizations of small Kr bubbles in nanograin and micrograin regions were compared. The grain boundary acted as an efficient defect sink, as evidenced by smaller bubbles and a lower bubble density in the nanograin region as compared to the micrograin region.
Presentations:
"Fission Products in Nuclear Fuel: Comparison of Simulated Distribution with Correlative Characterization Techniques" Todd Allen, Anter EL-AZAB, Jian Gan, Lingfeng He, Hunter Henderson, Michele Manuel, Billy Valderrama, Clarissa Yablinsky, Microscopy and Microanalysis August 4-8, (2012)
"Microstructural Investigation of Kr Irradiated UO2" Todd Allen, Jian Gan, Mahima Gupta, Lingfeng He, Clarissa Yablinsky, The Minerals, Materials, and Metals Society, 2013 Annual Meeting & Exhibition March 3-7, (2013)
"Study of Interfacial Interactions Using Thin Film Surface Modification" Alexander Mairov, Kumar Sridharan, Clarissa Yablinsky, ANS Annual Meeting June 24-28, (2012)

About Us

The Nuclear Science User Facilities (NSUF) is the U.S. Department of Energy Office of Nuclear Energy's only designated nuclear energy user facility. Through peer-reviewed proposal processes, the NSUF provides researchers access to neutron, ion, and gamma irradiations, post-irradiation examination and beamline capabilities at Idaho National Laboratory and a diverse mix of university, national laboratory and industry partner institutions.

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