Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “U”

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 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

129 I, 99 Tc, And U Distribution Coefficients of Subsurface Sediments Collected from the Proposed Site of the Environmental Management Disposal Facility

Performance Assessment calculations were completed in 2020 to evaluate the Environmental Management Disposal Facility (EMDF), a proposed new low-level radioactive waste (LLW) disposal facility on the U.S. Department of Energy’s Oak Ridge Reservation (ORR). Among the large number of input parameters needed for such calculations, are distribution coefficients (K d values; radionuclide concentration solid:liquid ratio) that provide a measure of the tendency of radionuclides to bind to sediments. The objective of this study was to measure K d values of three radionuclides that may pose a disproportionately large amount of risk, U, 129 I and 99 Tc. The average I K d value for the 14 geological materials recovered from the proposed EMDF site was 37.8 mL/g and ranged from -1.8 to 140.9 mL/g. These values were consistent, but somewhat larger than previous measurements made with ORR sediments and were about an order of magnitude greater than those used in previous EMDF PA calculations. The median Tc K d value was 365.7 mL/g, much greater than previously reported using ORR geological materials. Five of the 14 tested geological materials sorbed large quantities of Tc, suggesting that the weakly sorbing Tc(VII) species had been reduced to the sparingly soluble Tc(IV) species. The five strongly sorbing sediments had apparent Tc solubility values of approximately <10 -8 mol/L. The median U K d value was 5,726 mL/g. All of the tested geological materials had large K d values, ranging from 625 to >10,208 mL/g. Among the sediment samples that exhibited strong U binding, the apparent solubility value was approximately <10 -9 mol/L. Based on sediment properties and general ORR geological considerations, it was proposed that much of the I and Tc retention could be attributed to the site materials exhibiting low pH (average pH = 4.94), low redox status, and/or the elevated levels of iron oxides, manganese oxides, and natural organic matter. Similarly, the extremely high U binding measured in these sediments may also be attributed to the low conditions of carbonates, which can complex and therefore solubilize uranyl in these tests due to the low pH, and also the relatively high concentrations of iron and organic coatings on these samples. An implication of this study is that the areas of the EMDF subsurface environment may have natural properties for attenuating I, Tc, and U movement, and potentially other radionuclides, thereby possibly reducing risk posed by burial of LLW at this site. This document is a revision of SRNL-STI-2021-00404, Revision 0 that includes new data describing U K d values and new I and Tc K d values for four Nolichucky sediments. These new results were integrated into the data presented in the original document.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Parametric Study of 239 Pu and 235 U Mass Equivalency in Spherical Geometries

In this technical document, parametric studies were performed to determine if a bounding mass equivalency can be used to simplify multi-material models in MCNP6 for criticality evaluations. The studies explored the simplification of MCNP6 models by substituting materials, particularly 239 Pu for 235 U. The initial hypothesis for the material simplification is based on the subcritical mass limits from the ANSI/ANS- 8.1 standard which states that for water reflected metal spheres the limits are 20.1 kg 235 U and 5.0 kg 239 Pu. Using those masses, it was hypothesized that a 20.1 kg sphere of 235 U and a 5.0 kg sphere of 239 Pu could be considered to have the same multiplication. Given that equivalency, 4kg 235 U could be modeled by 1kg 239 Pu (i.e., a mass ratio of 4:1). The parametric studies compare the materials 239 Pu and 235 U independently and in multi-material spherical models. Critical mass, critical thickness, critical mass ratio and critical thickness ratio values are presented as functions of inner radius. keff values are presented as a function of inner radius at different mass ratios and total masses. Results indicate that the conservative bounding mass equivalency is one. That is, if substituting 239 Pu for 235 U it should be done on a gram for gram basis.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Investigation of U content in J-swipe/PIC samples

This final report documents the results of an evaluation of the U content in J-swipes for the International Atomic Energy Agency (IAEA). J-swipes are manufactured with inked numbers (1–30) and U backgrounds that are considered consistent across different lots and manufacturing times. These characteristics make them ideal for use by IAEA inspectors for pre-inspection check samples to ensure inspectors are not cross-contaminating sites. However, recent work has found elevated U concentrations in the inked numbers compared with the J-swipe material. To determine whether the inked numbers correlate with the U backgrounds, triplicate U content measurements were made on Swipes 1, 2, 11, 22, and 28. Triplicates of each swipe were processed through the standard chemistry used by the Oak Ridge National Laboratory Network of Analytical Laboratories team and analyzed for U content by isotope dilution via multicollector inductively coupled plasma mass spectrometry. Finally, samples were made by mass consisting of only ink areas and only cotton swipe material to determine the trace element differences between the cotton and the ink.

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEA↗
DOE OSTI2022

Towards physics-inspired data-driven weather forecasting: integrating data assimilation with a deep spatial-transformer-based U-NET in a case study with ERA5

Abstract. There is growing interest in data-driven weather prediction (DDWP), e.g., using convolutional neural networks such as U-NET that are trained on data from models or reanalysis. Here, we propose three components, inspired by physics, to integrate with commonly used DDWP models in order to improve their forecast accuracy. These components are (1) a deep spatial transformer added to the latent space of U-NET to capture rotation and scaling transformation in the latent space for spatiotemporal data, (2) a data-assimilation (DA) algorithm to ingest noisy observations and improve the initial conditions for next forecasts, and (3) a multi-time-step algorithm, which combines forecasts from DDWP models with different time steps through DA, improving the accuracy of forecasts at short intervals. To show the benefit and feasibility of each component, we use geopotential height at 500 hPa (Z500) from ERA5 reanalysis and examine the short-term forecast accuracy of specific setups of the DDWP framework. Results show that the spatial-transformer-based U-NET (U-STN) clearly outperforms the U-NET, e.g., improving the forecast skill by 45 %. Using a sigma-point ensemble Kalman (SPEnKF) algorithm for DA and U-STN as the forward model, we show that stable, accurate DA cycles are achieved even with high observation noise. This DDWP+DA framework substantially benefits from large (O(1000)) ensembles that are inexpensively generated with the data-driven forward model in each DA cycle. The multi-time-step DDWP+DA framework also shows promise; for example, it reduces the average error by factors of 2–3. These results show the benefits and feasibility of these three components, which are flexible and can be used in a variety of DDWP setups. Furthermore, while here we focus on weather forecasting, the three components can be readily adopted for other parts of the Earth system, such as ocean and land, for which there is a rapid growth of data and need for forecast and assimilation.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Materials Data on U(SiIr)2 by Materials Project

UIr2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Ir and eight equivalent Si atoms. All U–Ir bond lengths are 3.22 Å. All U–Si bond lengths are 3.07 Å. Ir is bonded to four equivalent U and four equivalent Si atoms to form a mixture of distorted edge, face, and corner-sharing IrU4Si4 tetrahedra. All Ir–Si bond lengths are 2.43 Å. Si is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Ir, and one Si atom. The Si–Si bond length is 2.30 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(MnGe)2 by Materials Project

UMn2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Mn and eight equivalent Ge atoms. All U–Mn bond lengths are 3.29 Å. All U–Ge bond lengths are 3.09 Å. Mn is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of face, edge, and corner-sharing MnU4Ge4 tetrahedra. All Mn–Ge bond lengths are 2.41 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Mn, and one Ge atom. The Ge–Ge bond length is 2.51 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(FeGe)2 by Materials Project

UFe2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Fe and eight equivalent Ge atoms. All U–Fe bond lengths are 3.12 Å. All U–Ge bond lengths are 3.11 Å. Fe is bonded in a 4-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Fe–Ge bond lengths are 2.32 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Fe, and one Ge atom. The Ge–Ge bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(CoGe)2 by Materials Project

UCo2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Co and eight equivalent Ge atoms. All U–Co bond lengths are 3.13 Å. All U–Ge bond lengths are 3.11 Å. Co is bonded in a 4-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Co–Ge bond lengths are 2.33 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Co, and one Ge atom. The Ge–Ge bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(GeIr)2 by Materials Project

UIr2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Ir and eight equivalent Ge atoms. All U–Ir bond lengths are 3.33 Å. All U–Ge bond lengths are 3.17 Å. Ir is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing IrU4Ge4 tetrahedra. All Ir–Ge bond lengths are 2.48 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Ir, and one Ge atom. The Ge–Ge bond length is 2.48 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(GeRh)2 by Materials Project

URh2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Rh and eight equivalent Ge atoms. All U–Rh bond lengths are 3.34 Å. All U–Ge bond lengths are 3.16 Å. Rh is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing RhU4Ge4 tetrahedra. All Rh–Ge bond lengths are 2.47 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Rh, and one Ge atom. The Ge–Ge bond length is 2.50 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(CuGe)2 by Materials Project

UCu2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Cu and eight equivalent Ge atoms. All U–Cu bond lengths are 3.28 Å. All U–Ge bond lengths are 3.11 Å. Cu is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing CuU4Ge4 tetrahedra. All Cu–Ge bond lengths are 2.43 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Cu, and one Ge atom. The Ge–Ge bond length is 2.46 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(GePd)2 by Materials Project

UPd2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Pd and eight equivalent Ge atoms. All U–Pd bond lengths are 3.37 Å. All U–Ge bond lengths are 3.19 Å. Pd is bonded to four equivalent U and four equivalent Ge atoms to form a mixture of distorted face, edge, and corner-sharing PdU4Ge4 tetrahedra. All Pd–Ge bond lengths are 2.53 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Pd, and one Ge atom. The Ge–Ge bond length is 2.43 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(SiRh)2 by Materials Project

URh2Si2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Rh and eight equivalent Si atoms. All U–Rh bond lengths are 3.21 Å. All U–Si bond lengths are 3.06 Å. Rh is bonded to four equivalent U and four equivalent Si atoms to form a mixture of distorted corner, edge, and face-sharing RhU4Si4 tetrahedra. All Rh–Si bond lengths are 2.42 Å. Si is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Rh, and one Si atom. The Si–Si bond length is 2.31 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(NiGe)2 by Materials Project

UNi2Ge2 crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. U is bonded in a 8-coordinate geometry to eight equivalent Ni and eight equivalent Ge atoms. All U–Ni bond lengths are 3.18 Å. All U–Ge bond lengths are 3.12 Å. Ni is bonded in a 4-coordinate geometry to four equivalent U and four equivalent Ge atoms. All Ni–Ge bond lengths are 2.36 Å. Ge is bonded in a 9-coordinate geometry to four equivalent U, four equivalent Ni, and one Ge atom. The Ge–Ge bond length is 2.47 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(MoO4)2 by Materials Project

UMo2O8 crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are five inequivalent U4+ sites. In the first U4+ site, U4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of U–O bond distances ranging from 2.31–2.50 Å. In the second U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six MoO4 tetrahedra. There are three shorter (2.20 Å) and three longer (2.21 Å) U–O bond lengths. In the third U4+ site, U4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of U–O bond distances ranging from 2.34–2.45 Å. In the fourth U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six MoO4 tetrahedra. All U–O bond lengths are 2.20 Å. In the fifth U4+ site, U4+ is bonded to six O2- atoms to form UO6 octahedra that share corners with six MoO4 tetrahedra. All U–O bond lengths are 2.19 Å. There are six inequivalent Mo6+ sites. In the first Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. In the second Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 26°. There are a spread of Mo–O bond distances ranging from 1.77–1.86 Å. In the third Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 21°. There are a spread of Mo–O bond distances ranging from 1.77–1.87 Å. In the fourth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 37°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. In the fifth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. In the sixth Mo6+ site, Mo6+ is bonded to four O2- atoms to form MoO4 tetrahedra that share a cornercorner with one UO6 octahedra. The corner-sharing octahedral tilt angles are 30°. There are a spread of Mo–O bond distances ranging from 1.77–1.85 Å. There are twenty-four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the second O2- site, O2- is bonded in a 2-coordinate geometry to one U4+ and one Mo6+ atom. In the third O2- site, O2- is bonded in a distorted linear geometry to one U4+ and one Mo6+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the ninth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the tenth O2- site, O2- is bonded in a linear geometry to one U4+ and one Mo6+ atom. In the eleventh O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twelfth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the thirteenth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the sixteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the seventeenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the eighteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the nineteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twentieth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-first O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-second O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one U4+ and one Mo6+ atom. In the twenty-fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one U4+ and one Mo6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Fe2Ge)2 by Materials Project

UFe4Ge2 crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. U is bonded in a 10-coordinate geometry to four equivalent Fe and six equivalent Ge atoms. All U–Fe bond lengths are 2.95 Å. There are two shorter (2.89 Å) and four longer (2.92 Å) U–Ge bond lengths. Fe is bonded in a 3-coordinate geometry to one U and three equivalent Ge atoms. There are two shorter (2.47 Å) and one longer (2.48 Å) Fe–Ge bond lengths. Ge is bonded in a 9-coordinate geometry to three equivalent U and six equivalent Fe atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Ru)2 by Materials Project

U(RuZn10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. There are four shorter (3.08 Å) and twelve longer (3.13 Å) U–Zn bond lengths. Ru is bonded to twelve Zn atoms to form RuZn12 cuboctahedra that share corners with six equivalent RuZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Ru cuboctahedra, and faces with six equivalent ZnUZn10Ru cuboctahedra. There are six shorter (2.52 Å) and six longer (2.77 Å) Ru–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.03 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Ru and six equivalent Zn atoms. There are two shorter (2.68 Å) and four longer (2.81 Å) Zn–Zn bond lengths. In the third Zn site, Zn is bonded to one U, one Ru, and ten Zn atoms to form distorted ZnUZn10Ru cuboctahedra that share corners with fifteen equivalent ZnUZn10Ru cuboctahedra, edges with two equivalent ZnUZn10Ru cuboctahedra, edges with three equivalent RuZn12 cuboctahedra, a faceface with one RuZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Ru cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.64–2.89 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on U(Zn10Co)2 by Materials Project

U(CoZn10)2 crystallizes in the cubic Fd-3m space group. The structure is three-dimensional. U is bonded in a 4-coordinate geometry to sixteen Zn atoms. There are four shorter (3.04 Å) and twelve longer (3.10 Å) U–Zn bond lengths. Co is bonded to twelve Zn atoms to form CoZn12 cuboctahedra that share corners with six equivalent CoZn12 cuboctahedra, edges with eighteen equivalent ZnUZn10Co cuboctahedra, and faces with six equivalent ZnUZn10Co cuboctahedra. There are six shorter (2.49 Å) and six longer (2.73 Å) Co–Zn bond lengths. There are three inequivalent Zn sites. In the first Zn site, Zn is bonded in a 2-coordinate geometry to two equivalent U and twelve equivalent Zn atoms. All Zn–Zn bond lengths are 3.00 Å. In the second Zn site, Zn is bonded in a distorted linear geometry to two equivalent Co and ten Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.64–2.77 Å. In the third Zn site, Zn is bonded to one U, one Co, and ten Zn atoms to form distorted ZnUZn10Co cuboctahedra that share corners with fifteen equivalent ZnUZn10Co cuboctahedra, edges with two equivalent ZnUZn10Co cuboctahedra, edges with three equivalent CoZn12 cuboctahedra, a faceface with one CoZn12 cuboctahedra, and faces with fifteen equivalent ZnUZn10Co cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.61–2.84 Å.

36 MATERIALS SCIENCE↗