Jian Gan

Profile Information
Name
Dr. Jian Gan
Institution
Idaho National Laboratory
Position
Research Scientist
Affiliation
Idaho National Laboratory
h-Index
ORCID
0000-0002-9121-4164
Expertise
Ion-Irradiation, Nuclear Fuel, Radiation Damage
Publications:
"2.6 MeV proton irradiation effects on the surface integrity of depleted UO2" Todd Allen, Anter EL-AZAB, Jian Gan, Mahima Gupta, Andrew Nelson, Janne Pakarinen, Nuclear Instruments and Methods B Vol. 319 2014 100-106 Link
The effect of low temperature proton irradiation in depleted uranium dioxide was examined as a function of fluence. With 2.6 MeV protons, the fluence limit for preserving a good surface quality was found to be relatively low, about 1.4 and 7.0 × 1017 protons/cm2 for single and poly crystalline samples, respectively. Upon increasing the fluence above this threshold, severe surface flaking and disintegration of samples was observed. Based on scanning electron microscopy (SEM) and X-ray diffraction (XRD) observations the causes of surface failure were associated to high H atomic percent at the peak damage region due to low solubility of H in UO2. The resulting lattice stress is believed to exceed the fracture stress of the crystal at the observed fluencies. The oxygen point defects from the displacement damage may hinder the H diffusion and further increase the lattice stress, especially at the peak damage region.
"A novel approach to determine the local burnup in irradiated fuels using Atom Probe Tomography (APT)" Mukesh Bachhav, Jian Gan, Dennis Keiser, Jeffrey Giglio, Daniel Jadernas, Ann Leenaers, Sven Van den Berghe, Journal of Nuclear Materials Vol. 528 2020 Link
"Atom probe study of irradiation-enhanced a' precipitation in neutron-irradiated Fe–Cr model alloys" Wei-Ying Chen, Jian Gan, Stuart Maloy, Kun Mo, Maria Okuniewski, James Stubbins, Yinbin Miao, Yaqiao Wu, Carolyn Tomchik, Journal of Nuclear Materials Vol. 462 2015 242-249 Link
Atom probe tomography (APT) was performed to study the effects of Cr concentrations, irradiation doses and irradiation temperatures on α′ phase formation in Fe–Cr model alloys (10–16 at.%) irradiated at 300 and 450 °C to 0.01, 0.1 and 1 dpa. For 1 dpa specimens, α′ precipitates with an average radius of 1.0–1.3 nm were observed. The precipitate density varied significantly from 1.1 × 1023 to 2.7 × 1024 1/m3, depending on Cr concentrations and irradiation temperatures. The volume fraction of α′ phase in 1 dpa specimens qualitatively agreed with the phase diagram prediction. For 0.01 dpa and 0.1 dpa, frequency distribution analysis detected slight Cr segregation in high-Cr specimens, but not in Fe–10Cr specimens. Proximity histogram analysis showed that the radial Cr concentration was highest at the center of α′ precipitates. For most precipitates, the Cr contents were significantly lower than that predicted by the phase diagram. The Cr concentration at precipitate center increased with increasing precipitate size.
"Bubble Character, Kr Distribution and Chemical Equilibrium in UO2" Todd Allen, Anter EL-AZAB, Jian Gan, Mahima Gupta, Lingfeng He, Hunter Henderson, Michele Manuel, Andrew Nelson, Janne Pakarinen, Billy Valderrama, Journal of Nuclear Materials Vol. 2015 Link
"Bubble evolution in Kr-irradiated UO2 during annealing" Lingfeng He, Xianming Bai, Janne Pakarinen, Brian Jaques, Jian Gan, Andrew Nelson, Anter EL-AZAB, Todd Allen, Journal of Nuclear Materials Vol. 496 2017 242-250 Link
Transmission electron microscopy observation of Kr bubble evolution in polycrystalline UO2 annealed at high temperature was conducted in order to understand the inert gas behavior in oxide nuclear fuel. The average diameter of intragranular bubbles increased gradually from 0.8 nm in as-irradiated sample at room temperature to 2.6 nm at 1600 °C and the bubble size distribution changed from a uniform distribution to a bimodal distribution above 1300 °C. The size of intergranular bubbles increased more rapidly than intragranular ones and bubble denuded zones near grain boundaries formed in all the annealed samples. It was found that high-angle grain boundaries held bigger bubbles than low-angle grain boundaries. Complementary atomistic modeling was conducted to interpret the effects of grain boundary character on the Kr segregation. The area density of strong segregation sites in the high-angle grain boundaries is much higher than that in the low angle grain boundaries.
"Bubble formation and Kr distribution in Kr-irradiated UO2" Todd Allen, Anter EL-AZAB, Jian Gan, Mahima Gupta, Andrew Nelson, Janne Pakarinen, Billy Valderrama, Lingfeng He, Abdel-Rahman Hassan, Hunter Henderson, Marquis Kirk, Michele Manuel, Journal of Nuclear Materials Vol. 456 2015 125-132 Link
In situ and ex situ transmission electron microscopy observation of small Kr bubbles in both single-crystal and polycrystalline UO2 were conducted to understand the inert gas bubble behavior in oxide nuclear fuel. The bubble size and volume swelling are shown as weak functions of ion dose but strongly depend on the temperature. The Kr bubble formation at room temperature was observed for the first time. The depth profiles of implanted Kr determined by atom probe tomography are in good agreement with the calculated profiles by SRIM, but the measured concentration of Kr is about 1/4 of the calculated concentration. This difference is mainly due to low solubility of Kr in UO2 matrix and high release of Kr from sample surface under irradiation.
"Bubble, stoichiometry, and chemical equilibrium of krypton-irradiated UO2" Todd Allen, Anter EL-AZAB, Jian Gan, Mahima Gupta, Lingfeng He, Michele Manuel, Janne Pakarinen, Billy Valderrama, Abdel-Rahman Hassan, Marquis Kirk, Andrew Nelson, Journal of Nuclear Materials Vol. 456 2015 125-132 Link
In situ and ex situ transmission electron microscopy observation of small Kr bubbles in bothsingle-crystal and polycrystalline UO2 were conducted to understand the inert gas bubblebehavior in oxide nuclear fuel. The bubble size and volume swelling are shown as a weakfunction of ion dose but strongly depend on the temperature. The Kr bubble formation at roomtemperature was observed for the first time. The depth profiles of implanted Kr determined byatom probe tomography are in good agreement with the calculated profiles by SRIM, but themeasured concentration of Kr is about 1/3 of calculated one. This difference is mainly due to lowsolubility of Kr in UO2 matrix, which has been confirmed by both density-functional theorycalculations and chemical equilibrium analysis.
"Effect of Grain Boundaries on Krypton Segregation Behavior in Irradiated Uranium Dioxide" Todd Allen, Darryl Butt, Jian Gan, Lingfeng He, Hunter Henderson, Brian Jaques, Michele Manuel, Janne Pakarinen, Billy Valderrama, Journal of Metals Vol. 66 2014 2562-2568 Link
Fission products, such as krypton (Kr), are known to be insoluble within UO2, segregating toward grain boundaries and eventually leading to a lowering in thermal conductivity and fuel swelling. Recent computational studies have identi?ed that differences in grain boundary structure have a signi?cant effect on the segregation behavior of fission products. However, experimental work supporting these simulations is lacking. Atom probe tomography was used to measure the Kr distribution across grain boundaries in UO2. Polycrystalline depleted UO2 samples were irradiated with 0.7 MeV and 1.8 MeV Kr-ions and annealed to 1000C, 1300C, and 1600C for 1 h to produce a Kr-bubble dominated microstructure. The results of this work indicate a strong dependence of Kr concentration as a function of grain boundary structure. Temperature also influences grain boundary chemistry with greater Kr concentration evident at higher temperatures, resulting in a reduced Kr concentration in the bulk. Although Kr segregation takes place at elevated temperatures, no change in grain size or texture was observed in the irradiated UO2 samples.
"Effects of neutron irradiation of Ti3SiC2 and Ti3AlC2 in the 121-1085 C temperature range" Michel Barsoum, Jian Gan, Elizabeth Hoffman, Darin Tallman, Lingfeng He, El'ad Caspi, Journal of Nuclear Materials Vol. 484 2017 120-134 Link
Herein we report on the formation of defects in response to neutron irradiation of polycrystalline Ti3SiC2 and Ti3AlC2 samples exposed to total fluences of ˜6 × 1020 n/m2, 5 × 1021 n/m2 and 1.7 × 1022 n/m2 at irradiation temperatures of 121(12), 735(6) and 1085(68)°C. These fluences correspond to 0.14, 1.6 and 3.4 dpa, respectively. After irradiation to 0.14 dpa at 121 °C and 735 °C, black spots are observed via transmission electron microscopy in both Ti3SiC2 and Ti3AlC2. After irradiation to 1.6 and 3.4 dpa at 735 °C, basal dislocation loops, with a Burgers vector of b = ½ [0001] are observed in Ti3SiC2, with loop diameters of 21(6) and 30(8) nm after 1.6 dpa and 3.4 dpa, respectively. In Ti3AlC2, larger dislocation loops, 75(34) nm in diameter are observed after 3.4 dpa at 735 °C, in addition to stacking faults. Impurity particles of TiC, as well as stacking fault TiC platelets in the MAX phases, are seen to form extensive dislocation loops under all conditions. Cavities were observed at grain boundaries and within stacking faults after 3.4 dpa irradiation, with extensive cavity formation in the TiC regions at 1085 °C. Remarkably, denuded zones on the order of 1 µm are observed in Ti3SiC2 after irradiation to 3.4 dpa at 735 °C. Small grains, 3–5 µm in diameter, are damage free after irradiation at 1085 °C at this dose. The results shown herein confirm once again that the presence of the A-layers in the MAX phases considerably enhance their irradiation tolerance. Based on these results, and up to 3.4 dpa, Ti3SiC2 remains a promising candidate for high temperature nuclear applications as long as the temperature remains >700 °C.
"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.
"Formation of tetragonal gas bubble superlattice in bulk molybdenum under helium ion implantation" Cheng Sun, David Sprouster, Khalid Hattar, Lynne Ecker, Lingfeng He, Y. Gao, Yipeng Gao, Yongfeng Zhang, Jian Gan, Scripta Materialia Vol. 149 2018 26-30 Link
We report the formation of tetragonal gas bubble superlattice in bulk molybdenum under helium ion implantation at 573 K. The transmission electron microscopy study shows that the helium bubble lattice constant measured from the in-plane d-spacing is ~4.5 nm, while it is ~3.9 nm from the out-of-plane measurement. The results of synchrotron-based small-angle x-ray scattering agree well with the transmission electron microscopy results in terms of the measurement of bubble lattice constant and bubble size. The coupling of transmission electron microscopy and synchrotron high-energy X-ray scattering provides an effective approach to study defect superlattices in irradiated materials.
"In Situ TEM Observation of Dislocation Evolution in Polycrystalline UO2" Todd Allen, Jian Gan, Mahima Gupta, Janne Pakarinen, Lingfeng He, Marquis Kirk, JOM Vol. 66 2014 2553-2561 Link
In situ transmission electron microscopy observation of polycrystalline UO2 (with average grain size of about 5 µm) irradiated with Kr ions at 600°C and 800°C was conducted to understand the radiation-induced dislocation evolution under the influence of grain boundaries. The dislocation evolution in the grain interior of polycrystalline UO2 was similar under Kr irradiation at different ion energies and temperatures. As expected, it was characterized by the nucleation and growth of dislocation loops at low irradiation doses, followed by transformation to extended dislocation lines and tangles at high doses. For the first time, a dislocation-denuded zone was observed near a grain boundary in the 1-MeV Kr-irradiated UO2 sample at 800°C. The denuded zone in the vicinity of grain boundary was not found when the irradiation temperature was at 600°C. The suppression of dislocation loop formation near the boundary is likely due to the enhanced interstitial diffusion toward grain boundary at the high temperature.
"Influence of instrument conditions on the evaporation behavior of uranium dioxide with UV laser-assisted atom probe tomography" Jian Gan, Billy Valderrama, Hunter Henderson, Michele Manuel, Journal of Nuclear Materials Vol. 459 2014 37-43 Link
Atom probe tomography (APT) provides the ability to detect subnanometer chemical variations spatially, with high accuracy. However, it is known that compositional accuracy can be affected by experimental conditions. A study of the effect of laser energy, specimen base temperature, and detection rate is performed on the evaporation behavior of uranium dioxide (UO2). In laser-assisted mode, tip geometry and standing voltage also contribute to the evaporation behavior. In this investigation, it was determined that modifying the detection rate and temperature did not affect the evaporation behavior as significantly as laser energy. It was also determined that three laser evaporation regimes are present in UO2. Very low laser energy produces a behavior similar to DC-field evaporation, moderate laser energy produces the desired laser-assisted field evaporation characteristic and high laser energy induces thermal effects, negatively altering the evaporation behavior. The need for UO2 to be analyzed under moderate laser energies to produce accurate stoichiometry distinguishes it from other oxides. The following experimental conditions providing the best combination of mass resolving power, accurate stoichiometry, and uniform evaporation behavior: 50 K, 10 pJ laser energy, a detection rate of 0.003 atoms per pulse, and a 100 kHz repetition rate.
"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.
"Microstructure changes and thermal conductivity reduction in UO2 following 3.9 MeV He2+ ion irradiation" Anter EL-AZAB, Jian Gan, Marat Khafizov, Andrew Nelson, Janne Pakarinen, Chris Wetteland, Lingfeng He, David Hurley, Todd Allen, Journal of Nuclear Materials Vol. 454 2014 283-289 Link
The microstructural changes and associated effects on thermal conductivity were examined in UO2 after irradiation using 3.9 MeV He2+ ions. Lattice expansion of UO2 was observed in X-ray diffraction after ion irradiation up to 5 × 1016 He2+/cm2 at low-temperature (<200 °C). Transmission electron microscopy (TEM) showed homogenous irradiation damage across an 8 μm thick plateau region, which consisted of small dislocation loops accompanied by dislocation segments. Dome-shaped blisters were observed at the peak damage region (depth around 8.5 μm) in the sample subjected to 5 × 1016 He2+/cm2, the highest fluence reached, while similar features were not detected at 9 × 1015 He2+/cm2. Laser-based thermo-reflectance measurements showed that the thermal conductivity for the irradiated layer decreased about 55% for the high fluence sample and 35% for the low fluence sample as compared to an un-irradiated reference sample. Detailed analysis for the thermal conductivity indicated that the conductivity reduction was caused by the irradiation induced point defects.
"Microstructure evolution in Xe-irradiated UO2 at room temperature" Todd Allen, Anter EL-AZAB, Jian Gan, Lingfeng He, Janne Pakarinen, Marquis Kirk, Andrew Nelson, Xianming Bai, Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms Vol. 330 2014 55-60 Link
In situ Transmission Electron Microscopy was conducted for single crystal UO2 to understand the microstructure evolution during 300 keV Xe irradiation at room temperature. The dislocation microstructure evolution was shown to occur as nucleation and growth of dislocation loops at low irradiation doses, followed by transformation to extended dislocation segments and tangles at higher doses. Xe bubbles with dimensions of 1-2 nm were observed after room-temperature irradiation. Electron Energy Loss Spectroscopy indicated that UO2 remained stoichiometric under room temperature Xe irradiation.
"Neutron irradiation effects in Fe and Fe-Cr at 300°C" Wei-Ying Chen, Yinbin Miao, Jian Gan, Maria Okuniewski, Stuart Maloy, James Stubbins, Acta Materialia Vol. 111 2016 407-416 Link
Fe and Fe-Cr (Cr = 10-16 at.%) specimens were neutron-irradiated at 300 °C to 0.01, 0.1 and 1 dpa. The TEM observations indicated that the Cr significantly reduced the mobility of dislocation loops and suppressed vacancy clustering, leading to distinct damage microstructures between Fe and Fe-Cr. Irradiation-induced dislocation loops in Fe were heterogeneously observed in the vicinity of grown-in dislocations, whereas the loop distribution observed in Fe-Cr is much more uniform. Voids were observed in the irradiated Fe samples, but not in irradiated Fe-Cr samples. Increasing Cr content in Fe-Cr results in a higher density, and a smaller size of irradiation-induced dislocation loops. Orowan mechanism was used to correlate the observed microstructure and hardening, which showed that the hardening in Fe-Cr can be attributed to the formation of dislocation loops and &#945;&#8242; precipitates.
"STEM-EDS/EELS and APT characterization of ZrN coatings on UMo fuel kernels" Lingfeng He, Mukesh Bachhav, Dennis Keiser, Emmanuel Perez, Brandon Miller, Jian Gan, Ann Leenaers, Sven Van den Berghe, Journal of Nuclear Materials Vol. 511 2018 174-182 Link
"Thermal stability of helium bubble superlattice in Mo under TEM in-situ heating" Jian Gan, Cheng Sun, Lingfeng He, Yongfeng Zhang, Chao Jiang, Yipeng Gao, Journal of Nuclear Materials Vol. 505 2018 207-211 Link
Although the temperature window of helium ion irradiation for gas bubble superlattice (GBS) formation was found to be in the range of approximately 0.15–0.35 melting point in literature, the thermal stability of He GBS has not been fully investigated. This work reports the experiment using an in-situ heating holder in a transmission electron microscope (TEM). A 3.0 mm TEM disc sample of Mo (99.95% pure) was irradiated with 40 keV He ions at 300 °C to a fluence of 1.0E+17 ions/cm2, corresponding to a peak He concentration of approximately 10 at.%, in order to introduce He GBS. In-situ heating was conducted with a ramp rate of ∼25 °C/min, hold time of ∼30 min, and temperature step of ∼100 °C up to 850 °C (0.39Tm homologous temperature). The result shows good thermal stability of He GBS in Mo with no noticeable change on GBS lattice constant and ordering. The implication of this unique and stable ordered microstructure on mechanistic understanding of GBS and its advanced application are discussed.
"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 &times; 1016 ions/cm2 at 600&deg;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:
"Atom probe analysis of a neutron irradiated Fe-14Cr model alloy" Jian Gan, Stuart Maloy, Yinbin Miao, Kun Mo, Yaqiao Wu, ICFRM 2013 January 1-9, (2013)
"Characterization of Oxide Fuel Surface Chemistry with Atom Probe Tomography" Anter EL-AZAB, Jian Gan, Hunter Henderson, Michele Manuel, Billy Valderrama, 2013 ANS Winter Meeting November 10-13, (2013)
"Comparison of Computationally Simulated Fission Product Distribution with Correlative Characterization Techniques in Surrogate Nuclear Fuel Materials" Todd Allen, Jian Gan, Lingfeng He, Hunter Henderson, Michele Manuel, Billy Valderrama, 2013 SACNAS National Conference October 2-6, (2013)
"Damage Structure Evolution in Ion Irradiated UO2" Todd Allen, Jian Gan, Mahima Gupta, Andrew Nelson, Jeff Terry, TMS 2014 February 16-20, (2014)
"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)
"Influence of Irradiation-induced Microstructural Defects on the Thermal Conductivity of Single Crystal Thorium Dioxide" Marat Khafizov, Amey Khanolkar, Zilong Hua, Cody Dennett, wangthink Wang, Tiankai Yao, Lingfeng He, Jian Gan, David Hurley, TMS 2020 February 23-27, (2020)
"Kr and Xe Bubble Characterization in CeO2" Todd Allen, Jian Gan, Mahima Gupta, Janne Pakarinen, TMS 2014 February 16-20, (2014)
"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)
"Microstructural Investigations of Kr and Xe Irradiated UO2" Todd Allen, Anter EL-AZAB, Jian Gan, Mahima Gupta, Lingfeng He, Hunter Henderson, Michele Manuel, Janne Pakarinen, Billy Valderrama, Energy Frontier Research Centers Principal Investigators Meeting July 18-19, (2013)
"Microstructure and Mechanical Property Studies on Neutron-Irradiated Ferritic FeCr Model Alloys" Jian Gan, Stuart Maloy, Yinbin Miao, Kun Mo, James Stubbins, Yaqiao Wu, TMS Annual Meeting February 16-20, (2014)
"Nano-scale Irradiation Induced Chemistry Changes in Oxide" Todd Allen, Jian Gan, Lingfeng He, Hunter Henderson, Michele Manuel, Janne Pakarinen, Billy Valderrama, 2014 TMS Annual Meeting February 16-20, (2014)
"Nano-scale Irradiation Induced Chemistry Changes in Oxide Fuel Materials" Todd Allen, Jian Gan, Hunter Henderson, Janne Pakarinen, Billy Valderrama, TMS 2014 February 16-20, (2014)
"Radiation Effects in UO2" Todd Allen, Jian Gan, Mahima Gupta, Michele Manuel, Andrew Nelson, Janne Pakarinen, Billy Valderrama, TMS 2014 February 16-20, (2014)
"Recent observations from the microstructural characterization of irradiated U-Mo fuels using advanced techniques" Dennis Keiser, Brandon Miller, Jian Gan, Lingfeng He, Daniel Jadernas, Mukesh Bachhav, NUMAT 2018 October 15-18, (2018)
NSUF Research Collaborations

Atom Probe Tomography to Study Annealing Temperature Dependence on Krypton Bubble Clustering in Uranium Dioxide - FY 2013 RTE Solicitation, #397

Atom Probe Tomography to Study Helium Segregation and Bubble Formation in Uranium Dioxide - FY 2013 RTE Solicitation, #395

Characterization of ferritic steels Fe-9Cr and 9Cr2WYT ODS alloys irradiated in ATR - FY 2017 RTE 1st Call, #813

Corrosion Test in Supercritical Water for Nitride-based Coatings on LWR Cladding - FY 2011 RTE Solicitation, #284

Electron Backscatter Diffraction and Atom Probe Tomography to Study Grain Boundary Chemistry Variation in Off Stoichiometric Uranium Dioxide Thin Films - FY 2013 RTE Solicitation, #429

Electron Backscatter Diffraction and Atom Probe Tomography to Study Krypton Segregation Behavior in Uranium Dioxide - FY 2013 RTE Solicitation, #409

In Situ Observation of Lunar Crater Features in Xe Irradiated UO2 at High Dose - FY 2016 RTE 2nd Call, #657

Investigation of gas bubble behavior under ion irradiation - FY 2017 RTE 2nd Call, #912

Lattice structure evolution in ion irradiated UO2. - FY 2014 RTE 3rd Call, #513

Microstructure Evolution in Ion Irradiated UO2. - FY 2014 RTE 1st Call, #472

Microstructures of Low-Dose He2+ and H+ Ion Irradiated UO2 - FY 2013 RTE Solicitation, #427

Post Irradiation Examination of Fiber Optic Temperature Sensors for In-Pile Temperature Monitor and Control for Advanced Test Reactor - FY 2017 RTE 2nd Call, #953

Study of the Microstructure of Irradiated CeO2 by Advanced Microscopy Techniques - FY 2011 RTE Solicitation, #327

Study of the Microstructure of Kr and Xe Irradiated UO2 by Advanced Microscopy Techniques - FY 2013 RTE Solicitation, #431

The window of gas-bubble superlattice formation in bcc metals - FY 2017 RTE 1st Call, #846

Transmission Electron Microscopy Study of the Microstructure Evolution in Kr Irradiated UO2 - FY 2014 RTE 2nd Call, #483