"Bubble morphology in U3Si2 implanted by high-energy Xe ions at 300ºC"
Yinbin Miao, Jason Harp, Kun Mo, Shaofei Zhu, Tiankai Yao, Jie Lian, Abdellatif Yacout,
Journal of Nuclear Materials
The microstructure modifications of a high-energy Xe implanted U3Si2, a promising accident tolerant fuel candidate, were characterized and are reported upon. The U3Si2 pellet was irradiated at Argonne Tandem Linac Accelerator System (ATLAS) by an 84 MeV Xe ion beam at 300 °C. The irradiated specimen was then investigated using a series of transmission electron microscopy (TEM) techniques. A dense distribution of bubbles were observed near the range of the 84 MeV Xe ions. Xe gas was also found to accumulate at multiple types of sinks, such as dislocations and grain boundaries. Bubbles aggregated at those sinks are slightly larger than intragranular bubbles in lattice. At 300 °C, the gaseous swelling strain is limited as all the bubbles are below 10 nm, implying the promising fission gas behavior of U3Si2 under normal operating conditions in light water reactors (LWRs).
"In situ synchrotron investigation of grain growth behavior of nano-grained UO2"
Jie Lian, Yinbin Miao, Kun Mo, Jun-Sang Park, Tiankai Yao, Jonathan Almer, Sumit Bhattacharya, Abdellatif Yacout,
The study of grain growth kinetics in nano-grained UO2 samples is reported. Dense nano-grained UO2 samples with well-controlled stoichiometry and grain size were fabricated using the spark plasma sintering technique. To determine the grain growth kinetics at elevated temperatures, a synchrotron wide-angle X-ray scattering (WAXS) study was performed in situ to measure the real-time grain size evolution based on the modified Williamson-Hall analysis. The unique grain growth kinetics of nanocrystalline UO2 at 730 °C and 820 °C were observed and explained by the difference in mobility of various grain boundaries.
"In-situ TEM study of the ion irradiation behavior of U3Si2 and U3Si5"
Tiankai Yao, Bowen Gong, Yinbin Miao, Jason Harp, Jie Lian,
Journal of Nuclear Materials
U3Si2 and U3Si5 are two important uranium silicide phases currently under extensive investigation as potential fuel forms or components for light water reactors (LWRs) to enhance accident tolerance. In this paper, their irradiation behaviors are studied by ion beam irradiations with various ion mass and energies, and their microstructure evolution is investigated by in-situ transmission electron microscopy (TEM). U3Si2 can easily be amorphized by ion beam irradiations (by 1 MeV Ar2+ or Kr2+) at room temperature with the critical amorphization dose less than 1 dpa. The critical amorphization temperatures of U3Si2 irradiated by 1 MeV Kr2+ and 1 MeV Ar2+ ion are determined as 580 ± 10 K and 540 ± 5 K, respectively. In contrast, U3Si5 remains crystalline up to 8 dpa at room temperature and is stable against ion irradiation-induced amorphization up to ∼50 dpa by either 1 MeV Kr2+ or 150 KeV Kr+ at 623 K. These results provide valuable experimental data to guide future irradiation experiments, support the relevant post irradiation examination, and serve as the experimental basis for the validation of advanced fuel performance models.
|"Measurement of grain boundary strength of Inconel X-750 superalloy using in-situ micro-tensile testing techniques in FIB/SEM system" Yachun Wang, Xiang Liu, Daniel Murray, Fei Teng, Wen Jiang, Mukesh Bachhav, Laura Hawkins, Emmanuel Perez, Cheng Sun, Xianming Bai, Jie Lian, Colin Judge, John Jackson, Robert Carter, Lingfeng He, Materials Science & Engineering Vol. 849 2022
"Nano-crystallization induced by high-energy heavy ion irradiation in UO2"
Yinbin Miao, Tiankai Yao, Jie Lian, Shaofei Zhu, Sumit Bhattacharya, Aaron Oaks, Adbdellatif Yacout,
Advanced microstructure investigations of the high-burnup structure (HBS) in UO2 produced by high-dose 84 MeV Xe ion irradiation are reported. Spark plasma sintered micro-grained UO2 was irradiated to 1357 dpa at 350 °C. The characteristic nano-grains and micro-pores of the HBS were formed. The grain size and grain boundary misorientation distributions of the HBS were measured using transmission electron microscopy based orientation imaging microscopy. Grain polygonization due to accumulation of radiation-induced dislocations was found to be the mechanism of nano-crystallization. The morphology of Xe bubbles was quantitatively investigated. This study provides crucial references for advanced fuel performance modeling of high-burnup UO2.
"Radiation-induced grain subdivision and bubble formation in U3Si2 at LWR temperature"
Bowen Gong, Jason Harp, Jie Lian, Tiankai Yao, Lingfeng He, Michael Tonks,
Journal of Nuclear Materials
U3Si2, an advanced fuel form proposed for light water reactors (LWRs), has excellent thermal conductivity and a high fissile element density. However, limited understanding of the radiation performance and fission gas behavior of U3Si2 is available at LWR conditions. This study explores the irradiation behavior of U3Si2 by 300 keV Xe+ ion beam bombardment combining with in-situ transmission electron microscopy (TEM) observation. The crystal structure of U3Si2 is stable against radiation-induced amorphization at 350 °C even up to a very high dose of 64 displacements per atom (dpa). Grain subdivision of U3Si2 occurs at a relatively low dose of 0.8 dpa and continues to above 48 dpa, leading to the formation of high-density nanoparticles. Nano-sized Xe gas bubbles prevail at a dose of 24 dpa, and Xe bubble coalescence was identified with the increase of irradiation dose. The volumetric swelling resulting from Xe gas bubble formation and coalescence was estimated with respect to radiation dose, and a 2.2% volumetric swelling was observed for U3Si2 irradiated at 64 dpa. Due to extremely high susceptibility to oxidation, the nano-sized U3Si2 grains upon radiation-induced grain subdivision were oxidized to nanocrystalline UO2 in a high vacuum chamber for TEM observation, eventually leading to the formation of UO2 nanocrystallites stable up to 80 dpa.
"Swift heavy ion track formation in Gd2Zr2-xTixO7 pyrochlore: Effect of electronic energy loss"
Maik Lang, Marcel Toulemonde, Jiaming Zhang, Fuxiang Zhang, Cameron Tracy, Jie Lian, Zhongwu Wang, William Weber, Daniel Severin, Markus Bender, Christina Trautmann, Rodney Ewing,
Nuclear Instruments and Methods in Physics Research, Section B: Beam Interactions with Materials and Atoms
The morphology of swift heavy ion tracks in the Gd2Zr2-xTixO7 pyrochlore system has been investigated as a function of the variation in chemical composition and electronic energy loss, dE/dx, over a range of energetic ions: 58Ni, 101Ru, 129Xe, 181Ta, 197Au, 208Pb, and 238U of 11.1 MeV/u specific energy. Bright-field transmission electron microscopy, synchrotron X-ray diffraction, and Raman spectroscopy reveal an increasing degree of amorphization with increasing Ti-content and dE/dx. The size and morphology of individual ion tracks in Gd2Ti2O7 were characterized by high-resolution transmission electron microscopy revealing a core–shell structure with an outer defect-fluorite dominated shell at low dE/dx to predominantly amorphous tracks at high dE/dx. Inelastic thermal-spike calculations have been used together with atomic-scale characterization of ion tracks in Gd2Ti2O7 by high resolution transmission electron microscopy to deduce critical energy densities for the complex core–shell morphologies induced by ions of different dE/dx.
|U.S. DOE Nuclear Science User Facilities Awards 30 Rapid Turnaround Experiment Research Proposals - Awards total nearly $1.2 million The U.S. Department of Energy (DOE) Nuclear Science User Facilities (NSUF) has selected 30 new Rapid Turnaround Experiment (RTE) projects, totaling up to approximately $1.2 million. These projects will continue to advance the understanding of irradiation effects in nuclear fuels and materials in support of the mission of the DOE Office of Nuclear Energy. Wednesday, April 26, 2017 - Calls and Awards
|DOE Awards 37 RTE Proposals - Awarded projects total nearly $1.4M in access awards Tuesday, July 14, 2020 - News Release, Calls and Awards
Ion Beam Irradiation and In-situ TEM characterization of High Entropy Titanate Pyrochlores - FY 2020 RTE 2nd Call, #4168
Micromechanical testing of Sintered UO2 fuel pellets with Controlled Microstructure - FY 2017 RTE 1st Call, #849
Radiation Response and Microstructure of Accident Tolerant U3Si2 Fuels by Ion Beam Irradiation - FY 2017 RTE 1st Call, #835
Characterization of fluff region in a EBR-II metallic fuel pin - FY 2023 RTE 3rd Call, #4753
Fission Gas Behavior and Fuel Swelling of Accident Tolerant U3Si2 Fuels by Ion Beam Irradiation - FY 2017 RTE 2nd Call, #957
Thermal Driven Grain Growth and Fission Gas Bubble Coarsening in Nano-grain Sized U3Si2 - FY 2019 RTE 1st Call, #1691