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At least 937 records · Page 52
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on ThBiAu2 by Materials Project

ThAu2Bi is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Th is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Th–Au bond lengths are 3.18 Å. Au is bonded in a body-centered cubic geometry to four equivalent Th and four equivalent Bi atoms. All Au–Bi bond lengths are 3.18 Å. Bi is bonded in a distorted body-centered cubic geometry to eight equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th3Se by Materials Project

Th3Se is Uranium Silicide-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Th is bonded in a distorted see-saw-like geometry to four equivalent Se atoms. There are two shorter (3.40 Å) and two longer (3.43 Å) Th–Se bond lengths. Se is bonded to twelve equivalent Th atoms to form a mixture of face and corner-sharing SeTh12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on GdThRu2 by Materials Project

ThGdRu2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Th is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Th–Ru bond lengths are 3.02 Å. Gd is bonded in a body-centered cubic geometry to eight equivalent Ru atoms. All Gd–Ru bond lengths are 3.02 Å. Ru is bonded in a body-centered cubic geometry to four equivalent Th and four equivalent Gd atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThUS2 by Materials Project

UThS2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. U is bonded to six equivalent S atoms to form US6 octahedra that share corners with six equivalent ThS6 octahedra, edges with six equivalent US6 octahedra, and edges with six equivalent ThS6 octahedra. The corner-sharing octahedral tilt angles are 3°. All U–S bond lengths are 2.75 Å. Th is bonded to six equivalent S atoms to form ThS6 octahedra that share corners with six equivalent US6 octahedra, edges with six equivalent US6 octahedra, and edges with six equivalent ThS6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Th–S bond lengths are 2.85 Å. S is bonded to three equivalent U and three equivalent Th atoms to form a mixture of corner and edge-sharing STh3U3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on HoThOs2 by Materials Project

ThHoOs2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Th is bonded in a body-centered cubic geometry to eight equivalent Os atoms. All Th–Os bond lengths are 3.02 Å. Ho is bonded in a body-centered cubic geometry to eight equivalent Os atoms. All Ho–Os bond lengths are 3.02 Å. Os is bonded in a body-centered cubic geometry to four equivalent Th and four equivalent Ho atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThMgAu2 by Materials Project

MgThAu2 is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Mg is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Mg–Au bond lengths are 3.09 Å. Th is bonded in a body-centered cubic geometry to eight equivalent Au atoms. All Th–Au bond lengths are 3.09 Å. Au is bonded in a body-centered cubic geometry to four equivalent Mg and four equivalent Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThCdCu2 by Materials Project

ThCu2Cd is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Th is bonded in a body-centered cubic geometry to eight equivalent Cu atoms. All Th–Cu bond lengths are 2.95 Å. Cu is bonded in a body-centered cubic geometry to four equivalent Th and four equivalent Cd atoms. All Cu–Cd bond lengths are 2.95 Å. Cd is bonded in a distorted body-centered cubic geometry to eight equivalent Cu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2SbNO by Materials Project

Th2SbNO crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Th4+ is bonded in a 4-coordinate geometry to four equivalent Sb3-, two equivalent N3-, and two equivalent O2- atoms. All Th–Sb bond lengths are 3.50 Å. Both Th–N bond lengths are 2.37 Å. Both Th–O bond lengths are 2.37 Å. Sb3- is bonded in a body-centered cubic geometry to eight equivalent Th4+ atoms. N3- is bonded to four equivalent Th4+ atoms to form NTh4 tetrahedra that share corners with four equivalent NTh4 tetrahedra and edges with four equivalent OTh4 tetrahedra. O2- is bonded to four equivalent Th4+ atoms to form OTh4 tetrahedra that share corners with four equivalent OTh4 tetrahedra and edges with four equivalent NTh4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2PS2 by Materials Project

(ThS)2P crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one phosphine molecule and two ThS clusters. In each ThS cluster, Th is bonded in a single-bond geometry to one S atom. The Th–S bond length is 2.33 Å. S is bonded in a single-bond geometry to one Th atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThBr2 by Materials Project

ThBr2 crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. Th is bonded in a square co-planar geometry to four equivalent Br atoms. There are two shorter (2.90 Å) and two longer (2.94 Å) Th–Br bond lengths. Br is bonded in a water-like geometry to two equivalent Th atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on ThBr2 by Materials Project

ThBr2 is Cyanogen Chloride-derived structured and crystallizes in the tetragonal I4_1/amd space group. The structure is zero-dimensional and consists of eight dibromothorium molecules. Th is bonded in a linear geometry to two equivalent Br atoms. Both Th–Br bond lengths are 2.70 Å. Br is bonded in a single-bond geometry to one Th atom.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Backbonding in Thorium(IV) and Uranium(IV) Diarsenido Complexes with t BuNC and CO

The coordination of tBuNC and CO with the diarsenido complexes (C 5 Me 5 ) 2 An(η 2 -As 2 Mes 2 ), An=Th, U, has been investigated. For the first time, a comparison between isostructural complexes of Th IV and U IV has been possible with CO; density functional calculations indicated an appreciable amount of π backbonding that originates from charge transfer from an actinide-arsenic sigma bond. The calculated CO stretching frequencies in the Th IV and U IV diarsenido complexes are consistent with the experimental measurements, both show large shifts to lower frequency. We demonstrate that the π backbonding is crucial to explaining the red shifts of CO frequency upon An IV complex formation. Interestingly, this interaction essentially correlates to the parallel orientation of π*(C-O) orbitals relative to the An-As bond.

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

ThH 5 : An Actinide–Containing Superhalogen Molecule

Thorium and its compounds have been widely investigated as important nuclear materials. Previous research focused on the potential use of thorium hydrides, such as ThH 2 , ThH 4 , and Th 4 H 15 , as nuclear fuels. Here, we report studies of the anion, ThH 5 , by anion photoelectron spectroscopy and computations. The resulting experimental and theoretical vertical detachment energies (VDE) for ThH 5 are 4.09 eV and 4.11 eV, respectively. These values and the agreement between theory and experiment facilitated the characterization of the structure of the ThH 5 anion and showed its neutral counterpart, ThH 5 to be a superhalogen. ThH 5 , which exhibits a C 4v structure with five Th–H single bonds, possesses the largest known H/M ratio among the actinide elements, M. Here, the adaptive natural density partitioning (AdNDP) method was used to further analyze the chemical bonding of ThH 5 – and to confirm the existence of five Th–H single bonds in the ThH 5 – molecular anion.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Thermophysical Properties of Mixtures of Thorium and Uranium Nitride

Abstract The miscibility, lattice parameter, and thermophysical properties of (Th 0.2 U 0.8 )N and (Th 0.5 U 0.5 )N have been investigated. It is shown that additions of thorium nitride (ThN) to uranium nitride (UN) increases the thermophysical performance of the mixed nitride fuel form in comparison to reference UN. In the more dilute limit, additions of ThN serve as a burnable neutronic poison and reduces the change in k eff over the lifecycle of the fuel. At higher concentrations, additions of ThN serve as a significant fertile source of 233 U. Where appropriate, comparisons to previous work on UN + PuN mixtures are made, as this is a comparable fuel form for potential fast reactor concepts, and a suitable point of contrast in the possible design space afforded by mixed (Th x U 1 − x )N fuel forms. The data from this work are the input parameters for finite element modeling of the temperature distribution in a compact reactor. The results of modeling and simulation of this core design are shown for the case of steady-state operation and during double, adjacent heat pipe failure.

Parker, S. S. (ORCID:000000018597440X)↗
DOE OSTI2026

Membrane-based solvent extraction for the recovery of rare earths from phosphate mining process streams

This study reports on the capture of rare earth elements (REEs) from phosphate industry process streams, including phosphoric acid (PA) sludge and phosphogypsum (PG), using a membrane solvent extraction (MSX) process. While MSX has been proven effective for a relatively concentrated feed, its effectiveness for dilute REEs solutions remains unexplored. Investigated PA-sludge and PG particles contain total REEs concentrations of ∼1100 and ∼320 ppm, respectively. Acid leaching, implemented to dissolve the REEs, significantly dilutes the REEs concentration to ∼210 ppm for PA-sludge leachate and ∼60 ppm for PG leachate. These low concentrations, compounded by the higher levels of non-REE ions and radioactive species, uranium (U) and thorium (Th), poses challenges to the MSX process. Here, we demonstrated that N,N,N′,N′-tetraoctyl-diglycolamide (TODGA) selectively binds REEs from a >3 M nitric-acid leachate while effectively rejecting U and Th. Concentrations of light REEs in strip solution were doubled compared to the feed, while heavy REEs were preferentially extracted. Furthermore, >99% purity gypsum, free of U and Th, was precipitated during the acid leaching process, aiding separation by removing significant amounts of non-REEs species (e.g., calcium) prior to the MSX process. Molecular simulations support the experimental data, suggesting preferential separation of heavy over light REEs. Based on these results, a cost-effective integrated process including pretreatment, acid leaching, MSX, and wastewater treatment is proposed for the co-recovery of REEs, phosphoric acid, gypsum, and U. This study shows MSX as a technically and economically feasible process for the recovery of REEs from low-concentration process streams, offering advantages over conventional solvent extraction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Capacity optimization of nuclear power integration to meet dynamic industrial demand

To decarbonize their industrial facilities, The Dow Chemical Company has collaborated with Idaho National Laboratory (INL) to study the integration of nuclear power with an industrial chemical facility. Using Holistic Energy and Resource Optimization Network developed at INL for optimizing and analyzing integrated energy systems, a nuclear microreactor system was sized and evaluated for dynamic dispatch to Dow Silicones Corporation’s Carrollton, KY (USA) site for iloxane production. It was found that a 180 MW th system (12 × 15MW th ) with 75.1 MWh th of thermal energy storage could provide heat and power to the chemical facilities. In the process, this would reduce electricity imports by 99.9 % and reduce the Scope 1 and 2 emissions of the site by 292,100 tonnes CO 2 /yr (98.8 %). The primary novelty of this work is a first of a kind design and optimization of a microreactor powered integrated energy system to provide heat and power to a chemical plant using real plant data. This analysis will pave the way for future studies using dispatchable clean energy sources to reduce carbon emissions and commodity industries’ reliance on fossil fuels.

22 - GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2023

Phase equilibria in iron-rich Sm–Fe–Ti and Sm–(Fe,Co)–Ti alloys at 1100–1200 °C

Iron-rich corners of ternary Sm–Fe–Ti phase diagram at 1100 °C and quasi-ternary Sm–Fe 0.8 Co 0.2 –Ti phase diagrams at 1100 and 1200 °C are constructed based on experimental investigation of equilibrated alloys with electron probe microanalysis, X-ray diffraction and thermomagnetic analysis. In addition, the upper boundaries of the temperature ranges of Sm(Fe,[Co,]Ti) 12 and Sm 3 (Fe,[Co,]Ti) 29 phases are determined with differential thermal analysis to update earlier rough estimates. The existence of a high-temperature phase of the Th 2 Ni 17 type, originally reported by Ivanova et al. [J. Alloys Compd. 224 (1995) 29], is confirmed. In the Sm–Fe 0.8 Co 0.2 –Ti system, the composition and equilibria of this hexagonal phase are established for 1200 °C; it is Sm-depleted (≈9.8 at.% Sm) compared to the 2:17 stoichiometry and it coexists with the rhombohedral 2:17 phase. The magnetic anisotropy of the cobalt-substituted Th 2 Ni 17 -type phase is planar, with the easy magnetization direction parallel to [100]. Equilibrium between a Sm-rich liquid phase and the 1:12 phase, which is important for the development of new high-performance permanent magnets, is absent up to 1000 °C, but does exist at 1100 °C (for the 1:12 phase with at least 8.7–8.9 at.% Ti) and at 1200 °C (for the 1:12 phase with as little as 7.4 at.% Ti). The development of magnets may be complicated, however, by an observed tendency of the high-temperature liquid to solidify into ferromagnetic phases including the Th 2 Ni 17 -type phase. The Curie temperatures of the α-(Fe,Ti), Sm(Fe,Ti) 12 , Sm 3 (Fe,Ti) 29 and rhombohedral Sm 2 (Fe,Ti) 17 phases are not only increased by the partial Co substitution for Fe, but their dependence on the Ti concentration is changed by this Co substitution from positive (or, for the 1:12 phase, zero) to negative values.

36 MATERIALS SCIENCE↗