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At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Th2N7OF15 by Materials Project

(Th2F9)2N2(NF)6(N3OF3)2 crystallizes in the cubic P2_13 space group. The structure is zero-dimensional and consists of four ammonia molecules, twelve monofluoroamine molecules, four N3OF3 clusters, and four Th2F9 clusters. In each N3OF3 cluster, N+1.29+ is bonded in a water-like geometry to one O2- and one F1- atom. The N–O bond length is 1.48 Å. The N–F bond length is 1.38 Å. O2- is bonded in a distorted trigonal non-coplanar geometry to three equivalent N+1.29+ atoms. F1- is bonded in a single-bond geometry to one N+1.29+ atom. In each Th2F9 cluster, Th4+ is bonded in a 6-coordinate geometry to six F1- atoms. There are three shorter (2.15 Å) and three longer (2.40 Å) Th–F bond lengths. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a single-bond geometry to one Th4+ atom. In the second F1- site, F1- is bonded in a single-bond geometry to one Th4+ atom. The F–Th bond length is 2.15 Å. In the third F1- site, F1- is bonded in a water-like geometry to two equivalent Th4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K2ThO3 by Materials Project

K2ThO3 is High Pressure (4-7GPa) Tellurium-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four ThO6 octahedra, edges with four ThO6 octahedra, and edges with eight KO6 octahedra. The corner-sharing octahedra tilt angles range from 16–19°. There are a spread of K–O bond distances ranging from 2.70–3.06 Å. In the second K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with six KO6 octahedra, edges with six KO6 octahedra, and edges with six ThO6 octahedra. The corner-sharing octahedra tilt angles range from 19–20°. All K–O bond lengths are 2.77 Å. In the third K1+ site, K1+ is bonded to six O2- atoms to form distorted KO6 octahedra that share corners with two equivalent KO6 octahedra, corners with four ThO6 octahedra, edges with four ThO6 octahedra, and edges with eight KO6 octahedra. The corner-sharing octahedra tilt angles range from 15–20°. There are a spread of K–O bond distances ranging from 2.66–3.03 Å. There are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded to six O2- atoms to form ThO6 octahedra that share corners with six KO6 octahedra, edges with three equivalent ThO6 octahedra, and edges with nine KO6 octahedra. The corner-sharing octahedra tilt angles range from 15–16°. There are four shorter (2.35 Å) and two longer (2.37 Å) Th–O bond lengths. In the second Th4+ site, Th4+ is bonded to six O2- atoms to form ThO6 octahedra that share corners with six KO6 octahedra, edges with three equivalent ThO6 octahedra, and edges with nine KO6 octahedra. The corner-sharing octahedra tilt angles range from 15–16°. There are two shorter (2.35 Å) and four longer (2.36 Å) Th–O bond lengths. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a 6-coordinate geometry to four K1+ and two Th4+ atoms. In the second O2- site, O2- is bonded in a 6-coordinate geometry to four K1+ and two Th4+ atoms. In the third O2- site, O2- is bonded to four K1+ and two Th4+ atoms to form a mixture of distorted corner and edge-sharing OK4Th2 octahedra. The corner-sharing octahedra tilt angles range from 0–14°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeThCN by Materials Project

ThCeCN is alpha Po-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Th4+ is bonded to four equivalent C4- and two equivalent N3- atoms to form ThC4N2 octahedra that share corners with six equivalent ThC4N2 octahedra, edges with four equivalent ThC4N2 octahedra, and edges with eight equivalent CeC2N4 octahedra. The corner-sharing octahedral tilt angles are 0°. All Th–C bond lengths are 2.62 Å. Both Th–N bond lengths are 2.59 Å. Ce3+ is bonded to two equivalent C4- and four equivalent N3- atoms to form CeC2N4 octahedra that share corners with six equivalent CeC2N4 octahedra, edges with four equivalent CeC2N4 octahedra, and edges with eight equivalent ThC4N2 octahedra. The corner-sharing octahedral tilt angles are 0°. Both Ce–C bond lengths are 2.59 Å. All Ce–N bond lengths are 2.62 Å. C4- is bonded to four equivalent Th4+ and two equivalent Ce3+ atoms to form CCe2Th4 octahedra that share corners with six equivalent CCe2Th4 octahedra, edges with four equivalent CCe2Th4 octahedra, and edges with eight equivalent NCe4Th2 octahedra. The corner-sharing octahedral tilt angles are 0°. N3- is bonded to two equivalent Th4+ and four equivalent Ce3+ atoms to form NCe4Th2 octahedra that share corners with six equivalent NCe4Th2 octahedra, edges with four equivalent NCe4Th2 octahedra, and edges with eight equivalent CCe2Th4 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Rb2Th3Mg(MoO4)8 by Materials Project

Rb2MgTh3(MoO4)8 crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Rb1+ is bonded in a 4-coordinate geometry to eight O2- atoms. There are a spread of Rb–O bond distances ranging from 2.91–3.44 Å. Mg2+ is bonded to six O2- atoms to form MgO6 octahedra that share corners with six MoO4 tetrahedra. There are a spread of Mg–O bond distances ranging from 2.07–2.16 Å. There are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.37–2.47 Å. In the second Th4+ site, Th4+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Th–O bond distances ranging from 2.35–2.54 Å. There are four inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. There is two shorter (1.79 Å) and two longer (1.80 Å) Mo–O bond length. In the second Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one MgO6 octahedra. The corner-sharing octahedral tilt angles are 15°. There are a spread of Mo–O bond distances ranging from 1.78–1.83 Å. In the third Mo6+ site, Mo6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of Mo–O bond distances ranging from 1.74–1.82 Å. In the fourth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share corners with two equivalent MgO6 octahedra. The corner-sharing octahedra tilt angles range from 13–36°. There are a spread of Mo–O bond distances ranging from 1.77–1.82 Å. There are sixteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted linear geometry to one Th4+ and one Mo6+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to one Rb1+, one Th4+, and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Th4+ and one Mo6+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Th4+ and one Mo6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Rb1+, one Th4+, and one Mo6+ atom. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to one Rb1+, one Mg2+, and one Mo6+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Th4+ and one Mo6+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Th4+, and one Mo6+ atom. In the ninth O2- site, O2- is bonded in a distorted linear geometry to one Rb1+, one Mg2+, and one Mo6+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Th4+, and one Mo6+ atom. In the eleventh O2- site, O2- is bonded in a linear geometry to one Mg2+ and one Mo6+ atom. In the twelfth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Th4+ and one Mo6+ atom. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Th4+ and one Mo6+ atom. In the fourteenth O2- site, O2- is bonded in a linear geometry to one Th4+ and one Mo6+ atom. In the fifteenth O2- site, O2- is bonded in a 1-coordinate geometry to one Rb1+, one Th4+, and one Mo6+ atom. In the sixteenth O2- site, O2- is bonded in a single-bond geometry to one Rb1+ and one Mo6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2ZrUO8 by Materials Project

UTh2ZrO8 is Fluorite-derived structured and crystallizes in the tetragonal P4mm space group. The structure is three-dimensional. U4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.34 Å) and four longer (2.37 Å) U–O bond lengths. There are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. All Th–O bond lengths are 2.40 Å. In the second Th4+ site, Th4+ is bonded in a body-centered cubic geometry to eight O2- atoms. All Th–O bond lengths are 2.40 Å. Zr4+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.30 Å) and four longer (2.31 Å) Zr–O bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded to four Th4+ atoms to form a mixture of corner and edge-sharing OTh4 tetrahedra. In the second O2- site, O2- is bonded to two equivalent Th4+ and two equivalent Zr4+ atoms to form a mixture of corner and edge-sharing OTh2Zr2 tetrahedra. In the third O2- site, O2- is bonded to two equivalent U4+ and two equivalent Zr4+ atoms to form a mixture of corner and edge-sharing OZr2U2 tetrahedra. In the fourth O2- site, O2- is bonded to two equivalent U4+ and two equivalent Th4+ atoms to form a mixture of corner and edge-sharing OTh2U2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on NaTh2(PO4)3 by Materials Project

NaTh2(PO4)3 crystallizes in the monoclinic Cc space group. The structure is three-dimensional. Na1+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Na–O bond distances ranging from 2.35–2.55 Å. There are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Th–O bond distances ranging from 2.31–2.61 Å. In the second Th4+ site, Th4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Th–O bond distances ranging from 2.36–2.67 Å. There are three inequivalent P5+ sites. In the first P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.53–1.58 Å. In the second P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.55–1.57 Å. In the third P5+ site, P5+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of P–O bond distances ranging from 1.53–1.57 Å. There are twelve inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to two Th4+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Th4+ and one P5+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to one Th4+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to one Na1+, one Th4+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Th4+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Na1+, one Th4+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Th4+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to two Th4+ and one P5+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to one Na1+, one Th4+, and one P5+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Th4+ and one P5+ atom. In the eleventh O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Th4+ and one P5+ atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to one Th4+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeThSi4 by Materials Project

ThCeSi4 is hexagonal omega structure-derived structured and crystallizes in the tetragonal I-4m2 space group. The structure is three-dimensional. Th4+ is bonded to twelve Si2- atoms to form ThSi12 cuboctahedra that share edges with four equivalent ThSi12 cuboctahedra, edges with eight equivalent CeSi12 cuboctahedra, faces with four equivalent ThSi12 cuboctahedra, and faces with four equivalent CeSi12 cuboctahedra. There are four shorter (3.14 Å) and eight longer (3.15 Å) Th–Si bond lengths. Ce4+ is bonded to twelve Si2- atoms to form CeSi12 cuboctahedra that share edges with four equivalent CeSi12 cuboctahedra, edges with eight equivalent ThSi12 cuboctahedra, faces with four equivalent ThSi12 cuboctahedra, and faces with four equivalent CeSi12 cuboctahedra. There are four shorter (3.13 Å) and eight longer (3.14 Å) Ce–Si bond lengths. There are three inequivalent Si2- sites. In the first Si2- site, Si2- is bonded in a 9-coordinate geometry to two equivalent Th4+, four equivalent Ce4+, and three Si2- atoms. There are one shorter (2.35 Å) and two longer (2.37 Å) Si–Si bond lengths. In the second Si2- site, Si2- is bonded in a 9-coordinate geometry to four equivalent Th4+, two equivalent Ce4+, and three Si2- atoms. The Si–Si bond length is 2.39 Å. In the third Si2- site, Si2- is bonded in a 9-coordinate geometry to four equivalent Th4+, two equivalent Ce4+, and three Si2- atoms. All Si–Th bond lengths are 3.15 Å. There are two shorter (2.37 Å) and one longer (2.39 Å) Si–Si bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Th2CoSi3 by Materials Project

Th2CoSi3 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are two inequivalent Th4+ sites. In the first Th4+ site, Th4+ is bonded in a 8-coordinate geometry to eight Si4- atoms. There are a spread of Th–Si bond distances ranging from 3.03–3.12 Å. In the second Th4+ site, Th4+ is bonded in a 10-coordinate geometry to ten Si4- atoms. There are eight shorter (3.14 Å) and two longer (3.22 Å) Th–Si bond lengths. Co4+ is bonded in a trigonal planar geometry to three Si4- atoms. There are one shorter (2.27 Å) and two longer (2.32 Å) Co–Si bond lengths. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to six Th4+, two equivalent Co4+, and one Si4- atom. The Si–Si bond length is 2.39 Å. In the second Si4- site, Si4- is bonded in a 9-coordinate geometry to six Th4+, one Co4+, and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.40 Å. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to six Th4+ and three Si4- atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Thermal Characterization and Exhumation of Northwest San Juan Basin Area, NM

The San Juan Basin (SJB), located in southwestern Colorado northwestern New Mexico, containing Paleozoic through middle Cenozoic strata, formed as a partitioned basin approximately 80 Ma in response to the Laramide orogeny. The SJB is a commercially mature, petroleum-producing basin, and currently being explored for CCUS and geothermal resources. Modern heat flow within the SJB is spatially variable with higher geothermal gradients in its northern and eastern portions. The temporal history of the basin thermal history is essential for understanding capacity for carbon storage and geothermal exploration. We present thermochronometric analyses of two surface and two subsurface samples to constrain spatial-temporal thermal evolution of the northwestern San Juan Basin. Apatite (U-Th)/He thermochronometric analyses were conducted on Cliff House and Kirtland Formation outcrops and subsurface samples of the Ojo Alamo and Pictured Cliffs Formations from a DOE funded, CCUS project pilot-well. In addition, vitrinite reflectance data and 1D basin modelling constrain possible time-temperature pathways of the samples in an area where no previous studies have constrained the uplift/exhumation of the Hogback Monocline using thermochronometry. Modeling suggests that elevated subsurface temperatures developed simultaneously with regional late Oligiocene volcanism in the San Juan Volcanic field and timing of maximum burial in the SJB. Late Miocene to Pliocene cooling/exhumation through the apatite (U-Th)/He partial retention zone support stratigraphic evidence of the Colorado Plateau uplift, possibly regional epeirogenic uplift driven by mantle processes.

02 PETROLEUM↗
DOE OSTI2022

Tailored Persistent Radical‐containing Heterotrimetal‐Organic Framework for Boosting Efficiency of Visible/NIR Light‐driven Photocatalytic CO 2 Reduction

Abstract Promoting light absorption range of photocatalysts is of great significance to improve solar light‐driven photocatalytic CO 2 reduction efficiency. Herein, a new viologen‐based multicomponent heterotrimetallic metal–organic framework (MOF) [Cu 3 Th 6 ( µ 3 ‐O) 4 ( µ 3 ‐OH) 4 (cpb) 12 ][Fe III (CN) 6 ] 6 (IHEP‐14) with an unprecedented (6, 18)‐connected she ‐ d topology is presented. Upon UV irradiation, this MOF undergoes ligand and iron photoreduction, and a single‐crystal‐to‐single‐crystal transformation to generate persistent radical‐containing MOF [Cu 3 Th 6 ( µ 3 ‐O) 4 ( µ 3 ‐OH) 4 (cpb • ) 12 ][Fe II (CN) 6 ] 6 (IHEP‐15). This radical‐containing MOF shows excellent stability without fading after at least 2 months in air. Besides extending the photoabsorption to a wider wavelength range covering from 200 to 2,500 nm, the generation of persistent radical in IHEP‐15 also largely enhances its CO 2 adsorption capacity by a factor of three due to the strong affinity between π orbital of the radical and the π system of CO 2 . These attributes endow IHEP‐15 with excellent visible/NIR light‐driven CO 2 photoreduction activity, with CO production rates under visible and NIR irradiation of 570.3 and 209.3 µmol h −1 g −1 , respectively. Notably, the latter is a record high for NIR‐induced CO production among all MOFs reported so far.

Hu, Kong‐Qiu↗
DOE OSTI2022

Quasi‐Homojunction Organic Nonfullerene Photovoltaics Featuring Fundamentals Distinct from Bulk Heterojunctions

Abstract In contrast to classical bulk heterojunction (BHJ) in organic solar cells (OSCs), the quasi‐homojunction (QHJ) with extremely low donor content (≤10 wt.%) is unusual and generally yields much lower device efficiency. Here, representative polymer donors and nonfullerene acceptors are selected to fabricate QHJ OSCs, and a complete picture for the operation mechanisms of high‐efficiency QHJ devices is illustrated. PTB7‐Th:Y6 QHJ devices at donor:acceptor (D:A) ratios of 1:8 or 1:20 can achieve 95% or 64% of the efficiency obtained from its BHJ counterpart at the optimal D:A ratio of 1:1.2, respectively, whereas QHJ devices with other donors or acceptors suffer from rapid roll‐off of efficiency when the donors are diluted. Through device physics and photophysics analyses, it is observed that a large portion of free charges can be intrinsically generated in the neat Y6 domains rather than at the D/A interface. Y6 also serves as an ambipolar transport channel, so that hole transport as also mainly through Y6 phase. The key role of PTB7‐Th is primarily to reduce charge recombination, likely assisted by enhancing quadrupolar fields within Y6 itself, rather than the previously thought principal roles of light absorption, exciton splitting, and hole transport.

Chemistry↗
DOE OSTI2020

Thorium chelators for targeted alpha therapy: Rapid chelation of thorium-226

We report one of the main challenges in targeted alpha therapy is assuring delivery of the α-particle dose to the targeted cells. Thus, it is critical to identify ligands for α-emitting radiometals that will form complexes that are very stable, both in vitro and in vivo. In this investigation, thorium-227 (t 1/2 = 18.70 days) chelation of ligands containing hydroxypyridinonate (HOPO) or picolinic acid (pa) moieties and the stability of the resultant complexes were studied. Chelation reactions were followed by reversed-phased HPLC and gamma spectroscopy. Studies revealed that high 227 Th chelation yields could be obtained within 2.5 h or less with ligands containing four Me-3,2-HOPO moieties, 1 (83%) and 2 (65%), and also with ligands containing pa moieties, H 4 octapa 3 (65%) and H 4 py4pa 6 (87%). No reaction occurred with H 4 neunpa-p-Bn-NO 2 4, and the chelation reaction with another pa ligand H 4 pypa 5 gave inconsistent yields with a very broad radio-HPLC peak. The ligands spermine-(Me-3,2-HOPO) 4 1, H 4 octapa 3, and H 4 py4pa 6 had high stability (i.e., 87% of 227 Th still bound to the ligand) in phosphate-buffered saline at room temperature over a 6-day period. Preliminary studies with ligand 6 demonstrated efficient chelation of thorium-226 (t 1/2 = 30.57 min) when heated to 80°C for 5 min.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Measurement of the Higgs boson production in association with top quarks in multilepton final states in pp collisions at s=13 TeV with the ATLAS detector

A measurement of the associated production of a top-quark pair with the Higgs boson (tt¯H$$ t\overline{t}H $$) in multilepton final states is presented. The analysis is based on a data sample of proton-proton collisions at s=13$$ \sqrt{s}=13 $$ TeV recorded with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 140 fb−1. Six final states defined by the number and flavour of reconstructed charged leptons are combined in a simultaneous likelihood fit to extract the tt¯H$$ t\overline{t}H $$ signal and constrain the most relevant backgrounds. The measured tt¯H$$ t\overline{t}H $$ cross-section normalised to Standard Model (SM) prediction is σtt¯H/σSM=0.63−0.19+0.20$$ {\sigma}_{t\overline{t}H}/{\sigma}^{\mathrm{SM}}=0.{63}_{-0.19}^{+0.20} $$. This result corresponds to an observed (expected) significance of 3.3σ (5.3σ). Additionally, two other fits are used to measure the tt¯H$$ t\overline{t}H $$ cross-section differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, and to extract the associated production cross-section of a single top-quark with the Higgs boson (tH) together with the tt¯H$$ t\overline{t}H $$ one. The CP structure of the top quark-Higgs boson Yukawa coupling is probed through an analysis of tt¯H$$ t\overline{t}H $$ and tH events. The results are compatible with the SM hypothesis, and values of the mixing angle between CP-even and CP-odd top-Higgs Yukawa couplings of |α| > 62° are excluded at 68% confidence level.

Aad, G↗
DOE OSTI2023

Selective Pb 2+ removal and electrochemical regeneration of fresh and recycled FeOOH

Heavy metal pollution is a key environmental problem. Selectively extracting heavy metals could accomplish water purification and resource recycling simultaneously. Adsorption is a promising approach with a facile process, adaptability for the broad concentration of feed water, and high selectivity. However, the adsorption method faces challenges in synthesizing high-performance sorbents and regenerating adsorbents effectively. FeOOH is an environmentally friendly sorbent with low-cost production on a large scale. Nevertheless, the selectivity behavior and regeneration of FeOOH are seldom studied. Therefore, we investigated the selectivity of FeOOH in a mixed solution of Co 2+ , Ni 2+ , and Pb 2+ and proposed to enhance the capacity of FeOOH and regenerate it by using external charges. Without charge, the FeOOH electrode shows a Pb 2+ uptake capacity of 20 mg/g. After applying a voltage of –0.2/+0.8 V, the uptake capacity increases to a maximum of 42 mg/g and the desorption ratio is 70%–80%. In 35 cycles, FeOOH shows a superior selectivity towards Pb 2+ compared with Co 2+ and Ni 2+ , with a purity of 97% ± 3% in the extracts. The high selectivity is attributed to the lower activation energy for Pb 2+ sorption. The capacity retentions at the 5 th and the 35 th cycles are ca. 80% and ca. 50%, respectively, comparable to the chemical regeneration method. With industrially exhausted granular ferric hydroxide as the electrode material, the system exhibits a Pb 2+ uptake capacity of 37.4 mg/g with high selectivity. Our work demonstrates the feasibility of regenerating FeOOH by charge and provides a new approach for recycling and upcycling FeOOH sorbent.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Effect of Zr and Sc additions on coarsening- and creep resistance of AlSi10Mg fabricated by laser powder bed fusion

Microstructure and creep properties are studied in a eutectic AlSi10Mg alloy modified with Zr and Sc additions (Al-9.8Si-0.32Mg-0.70Zr-0.23Sc, wt%) manufactured through laser powder-bed fusion (L-PBF). Three types of Zr/Sc-bearing powders - elemental, master-alloy, and pre-alloyed - are employed in the fabrication process, with the pre-alloyed powders providing the highest incorporation of Zr and Sc in the Al matrix. Here, the as-printed alloy exhibits a fine cellular Al-Si eutectic structure which fragments and coarsens into micron-sized Si particles during aging at 300 ºC, leading to a steady drop in alloy microhardness between 0.1 and 1000 h. Coarsening of the eutectic Si phase during aging is not measurably affected by Zr and Sc in solid solution, which precipitate during aging and increases strength, compensating weakening from Si coarsening between 1 and 200 h at 300 ºC. Atom-probe analysis in the peak-aged condition (96 h/300 °C) confirms the presence of Al 3 (Sc,Zr) secondary nano-precipitates with an average radius of 1.0 nm and some Si solubility. Micron-sized grains are present throughout the alloy, with ultra-fine-grained regions at the melt pool boundaries, neither of which coarsen during long-term aging at 300 ºC. Under creep conditions at 300 °C, the Zr/Sc-bearing alloy with Al 3 (Sc,Zr) nano-precipitates exhibits power-law behavior, with a high apparent stress exponent (n a = 9) and a high threshold stress (σ th = 43 MPa), exhibiting nearly double the strength of a Zr/Sc-free AlSi10Mg control alloy (σ th = 22 MPa).

36 MATERIALS SCIENCE↗
DOE OSTI2023

Multiphysics analysis of fuel fragmentation, relocation, and dispersal susceptibility–Part 3: Thermal hydraulic evaluation of large break LOCA under high-burnup conditions

Increasing the peak rod average burnup of pressurized water reactor (PWR) fuel beyond 62 GWd/tU may increase fuel fragmentation, relocation, and dispersal (FFRD) susceptibility during a large break loss of coolant accident (LBLOCA). TRACE thermal hydraulic (TH) LBLOCA analyses were performed for a realistic 24-month high-burnup PWR equilibrium cycle, to inform subsequent transient BISON high-burnup FFRD susceptibility evaluations. Realistic LBLOCA systems behavior was first established by configuring to and comparing with the BEMUSE OECD LBLOCA benchmark. Fuel and operating conditions were then applied from high-burnup VERA depletion calculations. LBLOCA simulations were performed for 281 selected high-burnup rods, for which transient TH boundary conditions were collected for later use in BISON. The TRACE results indicated that rod linear heat rate (rather than burnup) is the main predictor of peak cladding temperature (PCT) during the event. PCT typically occurred at a local burnup lower than the rod-average burnup, especially for twice-burned fuel.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2024

Californium-252 production at the High Flux Isotope Reactor - II: Comparison between the highly enriched uranium and a proposed low-enriched uranium core

This is the second paper on a 252 Cf production study performed in support of efforts to convert the High Flux Isotope Reactor (HFIR) from highly enriched uranium (HEU) to low-enriched uranium (LEU) fuel. The first paper primarily focuses on validating computational tools and nuclear data. This companion paper evaluates another critical aspect: the 252 Cf production capability with a proposed LEU core. HFIR must maintain its world-class performance and missions following conversion and because 252 Cf is a vital, multipurpose neutron-emitting radioisotope, the ability to efficiently produce 252 Cf must be preserved. In this study, the HFIRCON transport and depletion tool, several nuclear data libraries, and Campaign 78 data were used to compute 252 Cf production, sensitivity, and safety metrics. Further, results indicate the 252 Cf production and production rates are slightly higher with a 95MW th LEU core compared with those obtained with the 85MW th HEU core. Additionally, the target peak fission rate densities, discharge cumulative fission densities, and heat deposition rates with the LEU core are within a few percent of those calculated with the HEU core. The findings suggest HFIR’s 252 Cf production capability can be effectively maintained with an LEU core without adversely affecting the safety metrics.

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2025

MURR LEU structural and thermal hydraulics analyses: Part I – Preliminary irradiation thermo-mechanical behavior

The University of Missouri Research Reactor (MURR) is expected to be converted from highly enriched uranium (HEU, ≥ 20 wt% U-235) U-Al x dispersion fuel to low-enriched uranium (LEU, < 20 wt% U-235) with U-10Mo monolithic fuel. This work introduces high-fidelity irradiation thermo–mechanical (T-M) analysis of the MURR LEU focusing on changes in coolant channel gap thickness. Three-dimensional (3D) finite element (FE) models were developed to simulate the irradiation T-M behavior of the MURR LEU element with all 23 curved fuel plates, the two side plates, and the combs. It was shown that channel gap thickness changes were influenced not only by plate thickness variations due to fuel swelling and creep but also by the radial displacement of consecutive MURR LEU plates. Modeling the fuel element assembly captured side plate displacements, which were shown to reduce radial fuel plate displacements towards the convex side. The maximum local radial displacement in the element was predicted at the end of life (EOL) as 23.7 mil (602.0 µm) on the lateral centerline of plate 23 towards the convex side. The maximum stripe-averaged reduction in channel gap thickness, particularly relevant for thermal hydraulics (TH) safety analysis, was calculated as 15.9 mil (403.9 µm) in single-side heated channel 24 (the outermost channel). These results account for the thermal resistance from the oxide build-up on cladding surfaces which was shown to be up to 0.82 mil (20.8 µm) thick. It was demonstrated that accounting for oxide layer thermal resistance led to a 10 °C higher peak fuel temperature and a 4.4 mil (111.8 µm) greater maximum local radial displacement. The impact of the calculated channel gap thickness changes on the MURR LEU TH safety analysis is evaluated in Part II.

Irradiation thermo-mechanical analysis↗