Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Pd”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on GeBiPd6 by Materials Project

Pd6GeBi crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 1-coordinate geometry to seven Pd, one Ge, and three equivalent Bi atoms. There are a spread of Pd–Pd bond distances ranging from 2.69–3.16 Å. The Pd–Ge bond length is 2.49 Å. All Pd–Bi bond lengths are 2.90 Å. In the second Pd site, Pd is bonded in a 8-coordinate geometry to ten Pd, three equivalent Ge, and one Bi atom. There are a spread of Pd–Pd bond distances ranging from 2.70–3.02 Å. All Pd–Ge bond lengths are 2.74 Å. The Pd–Bi bond length is 2.96 Å. In the third Pd site, Pd is bonded in a 11-coordinate geometry to eight Pd and three equivalent Bi atoms. All Pd–Bi bond lengths are 3.16 Å. Ge is bonded in a body-centered cubic geometry to eight Pd atoms. Bi is bonded in a 8-coordinate geometry to fourteen Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BiPd6Se by Materials Project

Pd6BiSe crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 1-coordinate geometry to four equivalent Pd, three equivalent Bi, and one Se atom. There are three shorter (2.71 Å) and one longer (2.88 Å) Pd–Pd bond lengths. All Pd–Bi bond lengths are 2.90 Å. The Pd–Se bond length is 2.58 Å. In the second Pd site, Pd is bonded in a 3-coordinate geometry to four equivalent Pd, one Bi, and three equivalent Se atoms. There are one shorter (2.78 Å) and three longer (2.93 Å) Pd–Pd bond lengths. The Pd–Bi bond length is 2.97 Å. All Pd–Se bond lengths are 2.76 Å. In the third Pd site, Pd is bonded in a 11-coordinate geometry to eight Pd and three equivalent Bi atoms. All Pd–Bi bond lengths are 3.17 Å. Bi is bonded in a 8-coordinate geometry to fourteen Pd atoms. Se is bonded in a body-centered cubic geometry to eight Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ta4(Pd3Rh)3 by Materials Project

Ta4(RhPd3)3 is beta Cu3Ti-derived structured and crystallizes in the hexagonal P-6m2 space group. The structure is three-dimensional. there are three inequivalent Ta sites. In the first Ta site, Ta is bonded to six Rh and six equivalent Pd atoms to form TaPd6Rh6 cuboctahedra that share corners with twelve TaPd6Rh6 cuboctahedra, edges with eighteen PdTa4Pd8 cuboctahedra, faces with six equivalent TaPd9Rh3 cuboctahedra, and faces with six equivalent PdTa4Pd6Rh2 cuboctahedra. All Ta–Rh bond lengths are 2.79 Å. All Ta–Pd bond lengths are 2.80 Å. In the second Ta site, Ta is bonded to twelve Pd atoms to form TaPd12 cuboctahedra that share corners with twelve TaPd6Rh6 cuboctahedra, edges with eighteen PdTa4Pd8 cuboctahedra, faces with six equivalent TaPd9Rh3 cuboctahedra, and faces with twelve PdTa4Pd8 cuboctahedra. There are six shorter (2.79 Å) and six longer (2.80 Å) Ta–Pd bond lengths. In the third Ta site, Ta is bonded to three Rh and nine Pd atoms to form TaPd9Rh3 cuboctahedra that share corners with six equivalent TaPd9Rh3 cuboctahedra, corners with twelve equivalent PdTa4Pd6Rh2 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with eight TaPd6Rh6 cuboctahedra, and faces with nine PdTa4Pd8 cuboctahedra. All Ta–Rh bond lengths are 2.68 Å. There are six shorter (2.80 Å) and three longer (2.93 Å) Ta–Pd bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 12-coordinate geometry to four Ta, four Rh, and four equivalent Pd atoms. There are two shorter (2.78 Å) and two longer (2.81 Å) Rh–Rh bond lengths. All Rh–Pd bond lengths are 2.79 Å. In the second Rh site, Rh is bonded in a 12-coordinate geometry to four Ta, four equivalent Rh, and four equivalent Pd atoms. All Rh–Pd bond lengths are 2.79 Å. There are two inequivalent Pd sites. In the first Pd site, Pd is bonded to four Ta and eight Pd atoms to form distorted PdTa4Pd8 cuboctahedra that share corners with six equivalent PdTa4Pd8 cuboctahedra, edges with eight TaPd6Rh6 cuboctahedra, edges with twelve PdTa4Pd8 cuboctahedra, faces with four TaPd12 cuboctahedra, and faces with fourteen PdTa4Pd8 cuboctahedra. There are two shorter (2.78 Å) and six longer (2.81 Å) Pd–Pd bond lengths. In the second Pd site, Pd is bonded to four Ta, two Rh, and six Pd atoms to form distorted PdTa4Pd6Rh2 cuboctahedra that share corners with four equivalent TaPd9Rh3 cuboctahedra, corners with fourteen equivalent PdTa4Pd6Rh2 cuboctahedra, edges with six TaPd6Rh6 cuboctahedra, edges with eight PdTa4Pd8 cuboctahedra, faces with four TaPd6Rh6 cuboctahedra, and faces with eleven PdTa4Pd8 cuboctahedra. There are two shorter (2.77 Å) and two longer (2.81 Å) Pd–Pd bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsPd6Pb by Materials Project

Pd6PbAs crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 8-coordinate geometry to ten Pd, one Pb, and three equivalent As atoms. There are a spread of Pd–Pd bond distances ranging from 2.72–3.19 Å. The Pd–Pb bond length is 2.94 Å. All Pd–As bond lengths are 2.73 Å. In the second Pd site, Pd is bonded in a 8-coordinate geometry to seven Pd, three equivalent Pb, and one As atom. There are three shorter (2.69 Å) and one longer (2.84 Å) Pd–Pd bond lengths. All Pd–Pb bond lengths are 2.86 Å. The Pd–As bond length is 2.56 Å. In the third Pd site, Pd is bonded in a 11-coordinate geometry to eight Pd and three equivalent Pb atoms. All Pd–Pb bond lengths are 3.14 Å. Pb is bonded in a 8-coordinate geometry to fourteen Pd atoms. As is bonded in a body-centered cubic geometry to eight Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TlAsPd6 by Materials Project

Pd6TlAs crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 1-coordinate geometry to ten Pd, one Tl, and three equivalent As atoms. There are a spread of Pd–Pd bond distances ranging from 2.75–3.16 Å. The Pd–Tl bond length is 2.93 Å. All Pd–As bond lengths are 2.73 Å. In the second Pd site, Pd is bonded in a 8-coordinate geometry to seven Pd, three equivalent Tl, and one As atom. There are three shorter (2.67 Å) and one longer (2.82 Å) Pd–Pd bond lengths. All Pd–Tl bond lengths are 2.88 Å. The Pd–As bond length is 2.48 Å. In the third Pd site, Pd is bonded in a 11-coordinate geometry to eight Pd and three equivalent Tl atoms. All Pd–Tl bond lengths are 3.10 Å. Tl is bonded in a 8-coordinate geometry to fourteen Pd atoms. As is bonded in a body-centered cubic geometry to eight Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdW by Materials Project

PdW crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent W sites. In the first W site, W is bonded to six equivalent W and six Pd atoms to form WPd6W6 cuboctahedra that share corners with twelve WPd6W6 cuboctahedra, edges with twelve WPd6W6 cuboctahedra, edges with twelve PdPd6W6 cuboctahedra, faces with six equivalent WPd6W6 cuboctahedra, and faces with twelve PdPd6W6 cuboctahedra. All W–W bond lengths are 2.79 Å. All W–Pd bond lengths are 2.82 Å. In the second W site, W is bonded to ten equivalent W and six Pd atoms to form WPd6W10 cuboctahedra that share corners with ten PdPd6W6 cuboctahedra, corners with twelve WPd6W6 cuboctahedra, edges with eight PdPd6W6 cuboctahedra, edges with sixteen WPd6W6 cuboctahedra, faces with sixteen equivalent WPd6W10 cuboctahedra, and faces with eighteen PdPd6W6 cuboctahedra. There are a spread of W–W bond distances ranging from 2.79–5.58 Å. All W–Pd bond lengths are 2.82 Å. There are three inequivalent Pd sites. In the first Pd site, Pd is bonded to six equivalent W and six equivalent Pd atoms to form PdPd6W6 cuboctahedra that share corners with twelve PdPd6W6 cuboctahedra, edges with twelve equivalent WPd6W6 cuboctahedra, edges with twelve PdPd6W6 cuboctahedra, faces with six equivalent PdPd6W6 cuboctahedra, and faces with twelve equivalent WPd6W6 cuboctahedra. All Pd–Pd bond lengths are 2.79 Å. In the second Pd site, Pd is bonded to six W and six equivalent Pd atoms to form PdPd6W6 cuboctahedra that share corners with five equivalent WPd6W10 cuboctahedra, corners with twelve PdPd6W6 cuboctahedra, edges with ten WPd6W6 cuboctahedra, edges with twelve PdPd6W6 cuboctahedra, faces with six equivalent PdPd6W6 cuboctahedra, and faces with fifteen WPd6W6 cuboctahedra. All Pd–W bond lengths are 2.82 Å. All Pd–Pd bond lengths are 2.79 Å. In the third Pd site, Pd is bonded to six W and six equivalent Pd atoms to form PdPd6W6 cuboctahedra that share corners with five equivalent WPd6W10 cuboctahedra, corners with twelve PdPd6W6 cuboctahedra, edges with ten WPd6W6 cuboctahedra, edges with twelve PdPd6W6 cuboctahedra, faces with six equivalent PdPd6W6 cuboctahedra, and faces with fifteen WPd6W6 cuboctahedra. All Pd–Pd bond lengths are 2.79 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SnAsPd6 by Materials Project

Pd6SnAs crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 8-coordinate geometry to four equivalent Pd, one Sn, and three equivalent As atoms. There are one shorter (2.74 Å) and three longer (2.84 Å) Pd–Pd bond lengths. The Pd–Sn bond length is 2.86 Å. All Pd–As bond lengths are 2.72 Å. In the second Pd site, Pd is bonded in a distorted body-centered cubic geometry to four equivalent Pd, three equivalent Sn, and one As atom. There are three shorter (2.69 Å) and one longer (2.77 Å) Pd–Pd bond lengths. All Pd–Sn bond lengths are 2.81 Å. The Pd–As bond length is 2.60 Å. In the third Pd site, Pd is bonded in a 11-coordinate geometry to eight Pd and three equivalent Sn atoms. All Pd–Sn bond lengths are 3.12 Å. Sn is bonded in a distorted body-centered cubic geometry to fourteen Pd atoms. As is bonded in a body-centered cubic geometry to eight Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TaPd by Materials Project

PdTa crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Ta sites. In the first Ta site, Ta is bonded to six equivalent Ta and six Pd atoms to form distorted TaTa6Pd6 cuboctahedra that share corners with twelve TaTa6Pd6 cuboctahedra, edges with twelve TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent TaTa6Pd6 cuboctahedra, and faces with twelve PdTa6Pd6 cuboctahedra. All Ta–Ta bond lengths are 2.88 Å. All Ta–Pd bond lengths are 2.86 Å. In the second Ta site, Ta is bonded to ten equivalent Ta and six Pd atoms to form distorted TaTa10Pd6 cuboctahedra that share corners with ten PdTa6Pd6 cuboctahedra, corners with twelve TaTa6Pd6 cuboctahedra, edges with eight PdTa6Pd6 cuboctahedra, edges with sixteen TaTa6Pd6 cuboctahedra, faces with sixteen equivalent TaTa10Pd6 cuboctahedra, and faces with eighteen PdTa6Pd6 cuboctahedra. There are a spread of Ta–Ta bond distances ranging from 2.88–5.75 Å. All Ta–Pd bond lengths are 2.86 Å. There are three inequivalent Pd sites. In the first Pd site, Pd is bonded to six equivalent Ta and six equivalent Pd atoms to form distorted PdTa6Pd6 cuboctahedra that share corners with twelve PdTa6Pd6 cuboctahedra, edges with twelve equivalent TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent PdTa6Pd6 cuboctahedra, and faces with twelve equivalent TaTa6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.88 Å. In the second Pd site, Pd is bonded to six Ta and six equivalent Pd atoms to form distorted PdTa6Pd6 cuboctahedra that share corners with five equivalent TaTa10Pd6 cuboctahedra, corners with twelve PdTa6Pd6 cuboctahedra, edges with ten TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent PdTa6Pd6 cuboctahedra, and faces with fifteen TaTa6Pd6 cuboctahedra. All Pd–Ta bond lengths are 2.86 Å. All Pd–Pd bond lengths are 2.88 Å. In the third Pd site, Pd is bonded to six Ta and six equivalent Pd atoms to form distorted PdTa6Pd6 cuboctahedra that share corners with five equivalent TaTa10Pd6 cuboctahedra, corners with twelve PdTa6Pd6 cuboctahedra, edges with ten TaTa6Pd6 cuboctahedra, edges with twelve PdTa6Pd6 cuboctahedra, faces with six equivalent PdTa6Pd6 cuboctahedra, and faces with fifteen TaTa6Pd6 cuboctahedra. All Pd–Pd bond lengths are 2.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PdRh by Materials Project

RhPd is alpha La-derived structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are two inequivalent Rh sites. In the first Rh site, Rh is bonded to six equivalent Rh and six Pd atoms to form RhPd6Rh6 cuboctahedra that share corners with twelve RhPd6Rh6 cuboctahedra, edges with twelve RhPd6Rh6 cuboctahedra, edges with twelve PdPd6Rh6 cuboctahedra, faces with six equivalent RhPd6Rh6 cuboctahedra, and faces with twelve PdPd6Rh6 cuboctahedra. All Rh–Rh bond lengths are 2.76 Å. All Rh–Pd bond lengths are 2.75 Å. In the second Rh site, Rh is bonded to ten equivalent Rh and six Pd atoms to form RhPd6Rh10 cuboctahedra that share corners with ten PdPd6Rh6 cuboctahedra, corners with twelve RhPd6Rh6 cuboctahedra, edges with eight PdPd6Rh6 cuboctahedra, edges with sixteen RhPd6Rh6 cuboctahedra, faces with sixteen equivalent RhPd6Rh10 cuboctahedra, and faces with eighteen PdPd6Rh6 cuboctahedra. There are a spread of Rh–Rh bond distances ranging from 2.76–5.52 Å. All Rh–Pd bond lengths are 2.75 Å. There are three inequivalent Pd sites. In the first Pd site, Pd is bonded to six equivalent Rh and six equivalent Pd atoms to form PdPd6Rh6 cuboctahedra that share corners with twelve PdPd6Rh6 cuboctahedra, edges with twelve equivalent RhPd6Rh6 cuboctahedra, edges with twelve PdPd6Rh6 cuboctahedra, faces with six equivalent PdPd6Rh6 cuboctahedra, and faces with twelve equivalent RhPd6Rh6 cuboctahedra. All Pd–Pd bond lengths are 2.76 Å. In the second Pd site, Pd is bonded to six Rh and six equivalent Pd atoms to form PdPd6Rh6 cuboctahedra that share corners with five equivalent RhPd6Rh10 cuboctahedra, corners with twelve PdPd6Rh6 cuboctahedra, edges with ten RhPd6Rh6 cuboctahedra, edges with twelve PdPd6Rh6 cuboctahedra, faces with six equivalent PdPd6Rh6 cuboctahedra, and faces with fifteen RhPd6Rh6 cuboctahedra. All Pd–Rh bond lengths are 2.75 Å. All Pd–Pd bond lengths are 2.76 Å. In the third Pd site, Pd is bonded to six Rh and six equivalent Pd atoms to form PdPd6Rh6 cuboctahedra that share corners with five equivalent RhPd6Rh10 cuboctahedra, corners with twelve PdPd6Rh6 cuboctahedra, edges with ten RhPd6Rh6 cuboctahedra, edges with twelve PdPd6Rh6 cuboctahedra, faces with six equivalent PdPd6Rh6 cuboctahedra, and faces with fifteen RhPd6Rh6 cuboctahedra. All Pd–Pd bond lengths are 2.76 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on SbPd6S by Materials Project

Pd6SbS crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 8-coordinate geometry to four equivalent Pd, one Sb, and three equivalent S atoms. There are one shorter (2.70 Å) and three longer (2.83 Å) Pd–Pd bond lengths. The Pd–Sb bond length is 2.82 Å. All Pd–S bond lengths are 2.74 Å. In the second Pd site, Pd is bonded in a 1-coordinate geometry to four equivalent Pd, three equivalent Sb, and one S atom. There are three shorter (2.70 Å) and one longer (2.77 Å) Pd–Pd bond lengths. All Pd–Sb bond lengths are 2.82 Å. The Pd–S bond length is 2.58 Å. In the third Pd site, Pd is bonded in a 11-coordinate geometry to eight Pd and three equivalent Sb atoms. All Pd–Sb bond lengths are 3.14 Å. Sb is bonded in a distorted body-centered cubic geometry to fourteen Pd atoms. S is bonded in a body-centered cubic geometry to eight Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Chemical Interaction of Palladium in Uranium Oxycarbide Nuclear Fuel Kernel

Chemical Interaction of Palladium in Uranium Oxycarbide Nuclear Fuel Kernel Jana Howard1,3, Guang Yang3, Haiyan Zhao1*, Patrick Warren4, Tiankai Yao3, Steven Cavazos4 Elizabeth Sooby Wood4*, Ching-heng Shiau2 1 University of Idaho, Environmental Science, Idaho Falls, Idaho, USA 2 Boise State University, Microscopy and Characterization Suite, Idaho Falls, Idaho, USA 3 Idaho National Laboratory, Idaho Falls, Idaho, USA 4 University of Texas San Antonio, Department of Physics and Astronomy, San Antonio, Texas, USA *Corresponding author: haiyanz@uidaho.edu; elizabeth.soobywood@utsa.edu Tri-structural Isotropic (TRISO) particle fuel is the preferred choice for the newest and next-generation high-temperature nuclear reactors due to its robust construction [1]. The fuel design effectively contains fission products inside the particle at extremely high temperatures [2]. However, the effect of transition metal fission products on fuel performance and structural integrity remains largely unknown, creating uncertainties in predicting fuel performance and potential failure mechanisms [2]. For example, palladium (Pd) has a strong tendency to form intermetallic phases with uranium (U). These new phases tend to be hard and brittle which could lead to fracture of fuel kernel during irradiation [3,4]. Pd is not normally produced in high concentrations in normal fission reactions however, driving the production of Pd into the locality of a Uranium Oxycarbide (UCO) nuclear fuel provides an opportunity to closely observe the diffusion and chemical interactions. This study focuses on detailed transmission electron microscopy characterization of the intermetallic phases formed by the interaction between a UCO kernel and a Pd bar after annealing at 1100 °C for 100 hours. Figure 1 provides an overview of the UCO kernel in contact with the Pd bar. The UCO-Pd sample surface was examined using a Focused Ion Beam (FIB) Quanta 3D FEG FEI in VCD detector mode at 10kV, 83pA to reveal surface features. Several key surface features in the interaction region were observed including: (1) a small area with dendritic microstructure, (2) color contrast near the UCO kernel and Pd boundary, and (3) darker and lighter regions throughout the sample surface. To analyze diffusion behavior, FIB was used to prepare lamellae from five different areas of the UCO-Pd sample, as well as one for the as-received sample. These lamellae were examined using a Scanning Transmission Electron Microscope ThermoFisher Spectra 300 (STEM-Spectra). Energy Dispersive Spectroscopy results confirmed the diffusion between the UCO fuel and Pd bar. Figure 2 shows the identified phases of UC, UO2, and Pd dispersed throughout the interaction region. It was also found that the Pd concentration decreases as the radial distance from the UCO-Pd interface increases. The Pd concentration was 36.93% atomic fraction 11µm from the interaction region then decreased to 7.51% atomic fraction at 257 µm away from the interaction region. Figure 3 shows how concentrations of U and Pd vary across the interaction zone, highlighting the extent of diffusion. This study confirms that Pd interacts with surrounding material to form U-Pd phase and diffusion zones. These diffusion zones vary in composition depending on its radial distance from the point of contact with the Pd bar. These findings contribute to a deeper understanding of the fission product behavior in high temperature nuclear fuels, aiding in the prediction and mitigation of potential fuel degradation mechanisms. A B C Fig. 1. SEM micrographs of UCO fuel kernel in contact with solid Pd bar and the lift out locations. Figure 1A shows UCO fuel kernel in contact with solid Pd bar. Figure 1B shows a higher magnification image of the UCO fuel-Pd interaction zone. Figure 1C shows lift out sites for the lamellae. A B C Fig 2. EDS maps reveal the distribution of U, O, and Pd in location 3. Figure 2A shows the distribution of uranium. Figure 2B shows the distribution of oxygen. Figure 2C shows the distribution of palladium. A B C Fig 3. Palladium and uranium concentration across interaction zone in location 2. Figure 3A shows EDS map of lift out number 2. Figure 3B shows a zoomed in EDS map taken from the interaction zone. Figure 3C shows a line graph of uranium and palladium concentrations across the interaction zone. References: 1. B.E. Wells, N.R. Phillips, K.J. Geelhood. Pacific West Laboratory. (2021). TRISO Fuel: Properties and Failure Modes. https://www.nrc.gov/docs/ML2117/ML21175A152.pdf (Accessed January 16, 2025). 2. American Nuclear Society. TRISO Fuel Development Progresses in INL, ORNL. https://www.gen-4.org/gif/upload/docs/application/pdf/2014-03/nov13nn_fuel_reprint.pdf (Accessed January 16, 2025) 3. Clark R.A., M.A. Con

36 - MATERIALS SCIENCE↗
DOE OSTI2025

Chemical Interaction of Palladium in Uranium Oxycarbide Nuclear Fuel Kernel

Chemical Interaction of Palladium in Uranium Oxycarbide Nuclear Fuel Kernel Jana Howard1,3, Guang Yang3, Haiyan Zhao1*, Patrick Warren4, Tiankai Yao3, Steven Cavazos4 Elizabeth Sooby Wood4*, Ching-heng Shiau2 1 University of Idaho, Environmental Science, Idaho Falls, Idaho, USA 2 Boise State University, Microscopy and Characterization Suite, Idaho Falls, Idaho, USA 3 Idaho National Laboratory, Idaho Falls, Idaho, USA 4 University of Texas San Antonio, Department of Physics and Astronomy, San Antonio, Texas, USA *Corresponding author: haiyanz@uidaho.edu; elizabeth.soobywood@utsa.edu Tri-structural Isotropic (TRISO) particle fuel is the preferred choice for the newest and next-generation high-temperature nuclear reactors due to its robust construction [1]. The fuel design effectively contains fission products inside the particle at extremely high temperatures [2]. However, the effect of transition metal fission products on fuel performance and structural integrity remains largely unknown, creating uncertainties in predicting fuel performance and potential failure mechanisms [2]. For example, palladium (Pd) has a strong tendency to form intermetallic phases with uranium (U). These new phases tend to be hard and brittle which could lead to fracture of fuel kernel during irradiation [3,4]. Pd is not normally produced in high concentrations in normal fission reactions however, driving the production of Pd into the locality of a Uranium Oxycarbide (UCO) nuclear fuel provides an opportunity to closely observe the diffusion and chemical interactions. This study focuses on detailed transmission electron microscopy characterization of the intermetallic phases formed by the interaction between a UCO kernel and a Pd bar after annealing at 1100 °C for 100 hours. Figure 1 provides an overview of the UCO kernel in contact with the Pd bar. The UCO-Pd sample surface was examined using a Focused Ion Beam (FIB) Quanta 3D FEG FEI in VCD detector mode at 10kV, 83pA to reveal surface features. Several key surface features in the interaction region were observed including: (1) a small area with dendritic microstructure, (2) color contrast near the UCO kernel and Pd boundary, and (3) darker and lighter regions throughout the sample surface. To analyze diffusion behavior, FIB was used to prepare lamellae from five different areas of the UCO-Pd sample, as well as one for the as-received sample. These lamellae were examined using a Scanning Transmission Electron Microscope ThermoFisher Spectra 300 (STEM-Spectra). Energy Dispersive Spectroscopy results confirmed the diffusion between the UCO fuel and Pd bar. Figure 2 shows the identified phases of UC, UO2, and Pd dispersed throughout the interaction region. It was also found that the Pd concentration decreases as the radial distance from the UCO-Pd interface increases. The Pd concentration was 36.93% atomic fraction 11µm from the interaction region then decreased to 7.51% atomic fraction at 257 µm away from the interaction region. Figure 3 shows how concentrations of U and Pd vary across the interaction zone, highlighting the extent of diffusion. This study confirms that Pd interacts with surrounding material to form U-Pd phase and diffusion zones. These diffusion zones vary in composition depending on its radial distance from the point of contact with the Pd bar. These findings contribute to a deeper understanding of the fission product behavior in high temperature nuclear fuels, aiding in the prediction and mitigation of potential fuel degradation mechanisms. A B C Fig. 1. SEM micrographs of UCO fuel kernel in contact with solid Pd bar and the lift out locations. Figure 1A shows UCO fuel kernel in contact with solid Pd bar. Figure 1B shows a higher magnification image of the UCO fuel-Pd interaction zone. Figure 1C shows lift out sites for the lamellae. A B C Fig 2. EDS maps reveal the distribution of U, O, and Pd in location 3. Figure 2A shows the distribution of uranium. Figure 2B shows the distribution of oxygen. Figure 2C shows the distribution of palladium. A B C Fig 3. Palladium and uranium concentration across interaction zone in location 2. Figure 3A shows EDS map of lift out number 2. Figure 3B shows a zoomed in EDS map taken from the interaction zone. Figure 3C shows a line graph of uranium and palladium concentrations across the interaction zone. References: 1. B.E. Wells, N.R. Phillips, K.J. Geelhood. Pacific West Laboratory. (2021). TRISO Fuel: Properties and Failure Modes. https://www.nrc.gov/docs/ML2117/ML21175A152.pdf (Accessed January 16, 2025). 2. American Nuclear Society. TRISO Fuel Development Progresses in INL, ORNL. https://www.gen-4.org/gif/upload/docs/application/pdf/2014-03/nov13nn_fuel_reprint.pdf (Accessed January 16, 2025) 3. Clark R.A., M.A. Con

36 - MATERIALS SCIENCE↗
DOE OSTI2021

Understanding the origin of structure sensitivity in hydrodechlorination of trichloroethylene on a palladium catalyst

Periodic density functional theory (DFT) calculations are employed to understand the origin of structure sensitivity in hydrodechlorination (HDC) of trichloroethylene (TCE) over different facets of a palladium catalyst. The HDC reaction is simulated on the terrace (Pd (111) and Pd (100)) and undercoordinated (Pd (211) and Pd (110)) sites of the Pd catalyst. The most stable binding configuration of TCE on the Pd surfaces is observed to be through the di-σ mode of binding, wherein each carbon atom of the TCE molecule is adsorbed atop of the Pd atom. On comparing TCE adsorption over different facets of Pd, a maximum binding energy of –178 kJ mol –1 is calculated over the Pd (110) surface. TCE, upon adsorption on Pd catalyst, undergoes dechlorination followed by hydrogenation of the hydrocarbon intermediates. The activation energies for C–Cl bond dissociation steps are significantly low when compared to the hydrogenation steps. The chlorine released from dechlorination tends to block the active sites, thereby poisoning the surface with high binding energies (B.E > –160 kJ mol –1 ) on all the surfaces. The trend in chlorine binding energies on Pd facets follows: Pd (110) > Pd (211) > Pd (100) > Pd (111). The removal of surface chlorine is facilitated by its reaction with surface hydrogen to form hydrogen chloride. The activation energy for hydrogen chloride formation is calculated to be 90 kJ mol –1 and 88 kJ mol –1 on Pd (111) and Pd (100) terrace sites, respectively and 109 kJ mol –1 and 118 kJ mol –1 on the step Pd (211) and corrugated Pd (110) facets, respectively. This suggests the ease of removal of Cl as HCl from the terrace sites as compared to the step and corrugated sites. The structure sensitivity in the TCE HDC reaction could possibly arise due to the differences in the energetics of Cl removal on different Pd facets. As a result, this mechanistic understanding could provide a rationale for designing suitable catalysts for the HDC of TCE.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Materials Data on Tl9Pd13 by Materials Project

Pd13Tl9 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are four inequivalent Pd sites. In the first Pd site, Pd is bonded in a distorted linear geometry to six equivalent Pd and eight Tl atoms. All Pd–Pd bond lengths are 2.91 Å. There are two shorter (2.89 Å) and six longer (3.37 Å) Pd–Tl bond lengths. In the second Pd site, Pd is bonded in a 12-coordinate geometry to six Tl atoms. There are four shorter (2.85 Å) and two longer (3.02 Å) Pd–Tl bond lengths. In the third Pd site, Pd is bonded in a 12-coordinate geometry to six Tl atoms. There are four shorter (2.87 Å) and two longer (3.01 Å) Pd–Tl bond lengths. In the fourth Pd site, Pd is bonded in a 6-coordinate geometry to one Pd and six Tl atoms. There are a spread of Pd–Tl bond distances ranging from 2.76–2.97 Å. There are three inequivalent Tl sites. In the first Tl site, Tl is bonded in a distorted body-centered cubic geometry to eight Pd atoms. In the second Tl site, Tl is bonded in a 9-coordinate geometry to nine Pd atoms. In the third Tl site, Tl is bonded in a 8-coordinate geometry to nine Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PPd6 by Materials Project

Pd6P crystallizes in the monoclinic P2_1/c space group. The structure is zero-dimensional and consists of four Pd6P clusters. there are six inequivalent Pd sites. In the first Pd site, Pd is bonded in a distorted single-bond geometry to one P atom. The Pd–P bond length is 2.29 Å. In the second Pd site, Pd is bonded in a 1-coordinate geometry to one P atom. The Pd–P bond length is 2.28 Å. In the third Pd site, Pd is bonded in a 1-coordinate geometry to one P atom. The Pd–P bond length is 2.30 Å. In the fourth Pd site, Pd is bonded in a distorted single-bond geometry to one P atom. The Pd–P bond length is 2.29 Å. In the fifth Pd site, Pd is bonded in a distorted single-bond geometry to one P atom. The Pd–P bond length is 2.28 Å. In the sixth Pd site, Pd is bonded in a 1-coordinate geometry to one P atom. The Pd–P bond length is 2.30 Å. P is bonded in a 6-coordinate geometry to six Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BiPd by Materials Project

PdBi crystallizes in the orthorhombic Cmc2_1 space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 10-coordinate geometry to three Pd and seven Bi atoms. There are two shorter (2.90 Å) and one longer (3.08 Å) Pd–Pd bond lengths. There are a spread of Pd–Bi bond distances ranging from 2.91–3.14 Å. In the second Pd site, Pd is bonded in a 10-coordinate geometry to three Pd and seven Bi atoms. Both Pd–Pd bond lengths are 2.89 Å. There are a spread of Pd–Bi bond distances ranging from 2.90–3.31 Å. In the third Pd site, Pd is bonded in a 9-coordinate geometry to two Pd and seven Bi atoms. There are a spread of Pd–Bi bond distances ranging from 2.94–3.05 Å. There are three inequivalent Bi sites. In the first Bi site, Bi is bonded in a 7-coordinate geometry to seven Pd atoms. In the second Bi site, Bi is bonded in a 7-coordinate geometry to seven Pd atoms. In the third Bi site, Bi is bonded in a 7-coordinate geometry to seven Pd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Eu3(AsPd)4 by Materials Project

Eu3(PdAs)4 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are two inequivalent Eu sites. In the first Eu site, Eu is bonded in a 12-coordinate geometry to eight Pd and six As atoms. There are a spread of Eu–Pd bond distances ranging from 3.33–3.39 Å. There are four shorter (3.21 Å) and two longer (3.31 Å) Eu–As bond lengths. In the second Eu site, Eu is bonded to four equivalent Pd and eight equivalent As atoms to form a mixture of face and edge-sharing EuAs8Pd4 cuboctahedra. There are two shorter (3.21 Å) and two longer (3.22 Å) Eu–Pd bond lengths. All Eu–As bond lengths are 3.29 Å. There are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 9-coordinate geometry to six Eu and three As atoms. There are two shorter (2.47 Å) and one longer (2.49 Å) Pd–As bond lengths. In the second Pd site, Pd is bonded to four equivalent Eu, four equivalent Pd, and four equivalent As atoms to form a mixture of distorted face and corner-sharing PdEu4As4Pd4 cuboctahedra. All Pd–Pd bond lengths are 3.02 Å. There are two shorter (2.58 Å) and two longer (2.59 Å) Pd–As bond lengths. In the third Pd site, Pd is bonded to four equivalent Eu, four equivalent Pd, and four equivalent As atoms to form a mixture of distorted face and corner-sharing PdEu4As4Pd4 cuboctahedra. All Pd–As bond lengths are 2.66 Å. There are two inequivalent As sites. In the first As site, As is bonded in a 9-coordinate geometry to four equivalent Eu and five Pd atoms. In the second As site, As is bonded in a 9-coordinate geometry to six Eu, two equivalent Pd, and one As atom. The As–As bond length is 2.59 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AsPd3 by Materials Project

Pd3As crystallizes in the tetragonal I-4 space group. The structure is three-dimensional. there are three inequivalent Pd sites. In the first Pd site, Pd is bonded in a 4-coordinate geometry to twelve Pd and two equivalent As atoms. There are a spread of Pd–Pd bond distances ranging from 2.75–3.26 Å. There are one shorter (2.49 Å) and one longer (2.54 Å) Pd–As bond lengths. In the second Pd site, Pd is bonded in a 4-coordinate geometry to five Pd and four equivalent As atoms. There are a spread of Pd–Pd bond distances ranging from 2.85–2.95 Å. There are a spread of Pd–As bond distances ranging from 2.58–2.68 Å. In the third Pd site, Pd is bonded in a 2-coordinate geometry to ten Pd and three equivalent As atoms. Both Pd–Pd bond lengths are 2.97 Å. There are a spread of Pd–As bond distances ranging from 2.49–2.70 Å. As is bonded in a 9-coordinate geometry to nine Pd atoms.

36 MATERIALS SCIENCE↗