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At least 1,063 records · Page 59
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on PuAsO4 by Materials Project

PuAsO4 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Pu3+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pu–O bond distances ranging from 2.45–2.89 Å. As5+ is bonded in a tetrahedral geometry to four O2- atoms. There is three shorter (1.73 Å) and one longer (1.74 Å) As–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Pu3+ and one As5+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent Pu3+ and one As5+ atom. In the third O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Pu3+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Pu3+ and one As5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuInO3 by Materials Project

PuInO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pu3+ is bonded to twelve equivalent O2- atoms to form PuO12 cuboctahedra that share corners with twelve equivalent PuO12 cuboctahedra, faces with six equivalent PuO12 cuboctahedra, and faces with eight equivalent InO6 octahedra. All Pu–O bond lengths are 2.93 Å. In3+ is bonded to six equivalent O2- atoms to form InO6 octahedra that share corners with six equivalent InO6 octahedra and faces with eight equivalent PuO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All In–O bond lengths are 2.07 Å. O2- is bonded in a distorted linear geometry to four equivalent Pu3+ and two equivalent In3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuGaO3 by Materials Project

PuGaO3 is (Cubic) Perovskite structured and crystallizes in the cubic Pm-3m space group. The structure is three-dimensional. Pu3+ is bonded to twelve equivalent O2- atoms to form PuO12 cuboctahedra that share corners with twelve equivalent PuO12 cuboctahedra, faces with six equivalent PuO12 cuboctahedra, and faces with eight equivalent GaO6 octahedra. All Pu–O bond lengths are 2.74 Å. Ga3+ is bonded to six equivalent O2- atoms to form GaO6 octahedra that share corners with six equivalent GaO6 octahedra and faces with eight equivalent PuO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ga–O bond lengths are 1.94 Å. O2- is bonded in a distorted linear geometry to four equivalent Pu3+ and two equivalent Ga3+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuTeSO7 by Materials Project

PuTeSO7 crystallizes in the monoclinic P2_1/c space group. The structure is two-dimensional and consists of one PuTeSO7 sheet oriented in the (0, 0, 1) direction. Pu4+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Pu–O bond distances ranging from 2.09–2.58 Å. Te4+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Te–O bond distances ranging from 1.90–1.92 Å. S6+ is bonded in a tetrahedral geometry to four O2- atoms. There are a spread of S–O bond distances ranging from 1.46–1.52 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted single-bond geometry to one Pu4+ and one S6+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Pu4+ and one Te4+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Pu4+ and one Te4+ atom. In the fourth O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent Pu4+ and one S6+ atom. In the fifth O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Pu4+ and one Te4+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to one Pu4+ and one S6+ atom. In the seventh O2- site, O2- is bonded in a single-bond geometry to one S6+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2PuTaO6 by Materials Project

Ba2PuTaO6 is (Cubic) Perovskite-derived structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Ba2+ is bonded to twelve equivalent O2- atoms to form BaO12 cuboctahedra that share corners with twelve equivalent BaO12 cuboctahedra, faces with six equivalent BaO12 cuboctahedra, faces with four equivalent PuO6 octahedra, and faces with four equivalent TaO6 octahedra. All Ba–O bond lengths are 3.05 Å. Pu3+ is bonded to six equivalent O2- atoms to form PuO6 octahedra that share corners with six equivalent TaO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Pu–O bond lengths are 2.29 Å. Ta5+ is bonded to six equivalent O2- atoms to form TaO6 octahedra that share corners with six equivalent PuO6 octahedra and faces with eight equivalent BaO12 cuboctahedra. The corner-sharing octahedral tilt angles are 0°. All Ta–O bond lengths are 2.02 Å. O2- is bonded in a distorted linear geometry to four equivalent Ba2+, one Pu3+, and one Ta5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuUN2 by Materials Project

PuUN2 is Caswellsilverite structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Pu3+ is bonded to six equivalent N3- atoms to form PuN6 octahedra that share corners with six equivalent UN6 octahedra, edges with six equivalent PuN6 octahedra, and edges with six equivalent UN6 octahedra. The corner-sharing octahedral tilt angles are 3°. All Pu–N bond lengths are 2.49 Å. U3+ is bonded to six equivalent N3- atoms to form UN6 octahedra that share corners with six equivalent PuN6 octahedra, edges with six equivalent PuN6 octahedra, and edges with six equivalent UN6 octahedra. The corner-sharing octahedral tilt angles are 3°. All U–N bond lengths are 2.39 Å. N3- is bonded to three equivalent Pu3+ and three equivalent U3+ atoms to form a mixture of corner and edge-sharing NPu3U3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPu2F9 by Materials Project

KPu2F9 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. K1+ is bonded in a 6-coordinate geometry to ten F1- atoms. There are a spread of K–F bond distances ranging from 2.63–3.18 Å. Pu4+ is bonded in a 9-coordinate geometry to nine F1- atoms. There are a spread of Pu–F bond distances ranging from 2.29–2.40 Å. There are five inequivalent F1- sites. In the first F1- site, F1- is bonded in a linear geometry to two equivalent Pu4+ atoms. In the second F1- site, F1- is bonded in a 3-coordinate geometry to two equivalent K1+ and two equivalent Pu4+ atoms. In the third F1- site, F1- is bonded in a distorted bent 150 degrees geometry to one K1+ and two equivalent Pu4+ atoms. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to one K1+ and two equivalent Pu4+ atoms. In the fifth F1- site, F1- is bonded in a trigonal planar geometry to one K1+ and two equivalent Pu4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuB12 by Materials Project

PuB12 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pu6+ is bonded in a 1-coordinate geometry to twenty-four equivalent B+0.50- atoms. All Pu–B bond lengths are 2.78 Å. B+0.50- is bonded in a 7-coordinate geometry to two equivalent Pu6+ and five equivalent B+0.50- atoms. There is one shorter (1.71 Å) and four longer (1.79 Å) B–B bond length.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuPaO4 by Materials Project

PuPaO4 is Fluorite-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. Pu3+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Pu–O bond lengths are 2.40 Å. Pa5+ is bonded in a body-centered cubic geometry to eight equivalent O2- atoms. All Pa–O bond lengths are 2.32 Å. O2- is bonded to two equivalent Pu3+ and two equivalent Pa5+ atoms to form a mixture of corner and edge-sharing OPu2Pa2 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Thermal Evaluation of the SAVY-4000 1 Quart Container at High Heat Loads

The SAVY-4000 Safety Analysis Report (SAR) was published in 2013 which established the design life of the container series through physical testing that meets applicable requirements from DOE M 441.1-1, Nuclear Material Packaging Manual. One critical requirement in DOE M 441.1-1 is to set a maximum heat load for the entire series to ensure that throughout the lifetime of the container, each of the components still performs within manufacture specifications. The original maximum decay heat limit has been defined within the SAVY-4000 SAR, which was accomplished by completing a series of tests that heat loaded the SAVY-4000 series and measured the steady state temperature and graded it against manufacture specifications. The container series is comprised of a corrosion resistant 316L stainless steel containment boundary, ceramic composite filter for the prevention of radiological particulate release and a chemically stable O-ring made of Viton ® . Currently, the SAVY 4000 maximum decay heat load is set at 25 Watts and the heat load expected during normal handling and storage is considered sufficient that the SAVY 4000 container requirements will not be the limiting factor for storage of most common material in use at TA-55, e.g. weapons grade oxide, americium, Pu-238 oxide and encapsulated heat sources. The SAVY 4000 lifetime was originally set as 5 years within the SAVY-4000 SAR, but in July 2019 the lifetime was extended to 15 years through a technical basis justification approved by the Department of Energy (DOE) Los Alamos Field Office. The 25 Watt limit applies to all SAVY 4000 container sizes; 1-quart, 2-quart, 3-quart, 5-quart, 8-quart, 12-quart, 5-gallon, and 10-gallon.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Gamma ray analysis of the K2 containers

The K2 containers contain PuO2 with 238 Pu being the most abundant isotope of all plutonium isotopes. The purpose of this analysis is to determine the light element impurities in the PuO2. These light elements can interact with the alpha particles from plutonium decay to release gamma rays, protons, and neutrons through the reactions (α,α’), (α,p), and (α,n) respectively. The gamma rays released by the interactions can be measured and compared with the gamma rays released by the plutonium. The ratios of the gamma rays from the interactions and the plutonium gamma rays allow for the determination of the impurities in the items. The elements that can be detected are Lithium (Z=3), Beryllium (Z=4), Boron (Z=5), Fluorine (Z=9), Sodium (Z=11), Magnesium (Z=12), Aluminum (Z=13), Silicon (Z=14), Phosphorous (Z=15), Chlorine (Z=17), and Potassium (Z=19).

07 ISOTOPE AND RADIATION SOURCES↗
DOE OSTI2021

LANL Critical Benchmark Comparison Study and Subsequent Revision for Cases Involving LEU and MIX

As part of an international collaboration within the DOE Nuclear Criticality Safety Program (NCSP), LANL is involved in a comparison study to quantify differences in k-effective results from neutron transport simulations of critical benchmark experiments. The DOE NCSP Mission and Vision details the activity in which the French Institut de Radioprotection et de Sûreté Nucléaire (IRSN) leads the study with LANL, ORNL, and LLNL to compare results of various neutron transport codes and nuclear data libraries for ICSBEP benchmarks held in common by the entities. The task statement from the DOE NCSP Five-Year Execution Plan is given as: "The proposal is for IRSN to lead a new intercomparison based on the MORET code with the latest JEFF-3.3 data and ENDF/B-VIII.0 data, when available, using their existing comprehensive selection of 2,714 benchmarks and collate their results together with those from LLNL (COG), LANL (MCNP) and ORNL (SCALE). Due to the large number of benchmarks involved, this effort is envisioned to take three years with an additional year for IRSN to complete a summary report. The benchmark development will be performed independently to minimize modeling errors through discovery and resolution of discrepant results. A summary report will be generated (led by IRSN) to document the results of this study." This report documents results obtained for revisions made to cases involving Intermediate Enriched Uranium (IEU) and a mixture of Pu and Uranium (MIX), with a focus on the changes made to LANL benchmarks modeled with MCNP6 using ENDF/B-VII.1 nuclear data that appeared to have discrepant results when compared with results of other codes. Feedback was used to pinpoint review of particular benchmark input files and to revise them when necessary. This report documents the results of review and revision of specific benchmarks highlighted as possibly discrepant in the comparison study. In addition, there is an effort tied to this work involving collaboration between LANL XCP and NCS Divisions in the development of a shared review/revision procedure and use of a new benchmark repository.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

Which nuclear data can be validated with LLNL pulsed-sphere experiments? [Slides]

LLNL pulsed sphere are a very valuable experiment series to validate scattering and fission nuclear data. It would be great if they could be evaluated as benchmarks and make it into SINBAD! We see potential issues in ENDF/B-VIII.0 6 Li, 12 C, 16 O, 24- 26 Mg, 27 Al, 48 Ti, 56 Fe, and 208 Pb nuclear data. Good agreement is found with 1,2 H, 7 Li, 9 Be, 14 N, 235,238 U, and 239 Pu nuclear data.

16O and 12C Spheres↗
DOE OSTI2020

TEX-HEU: Integral Experiments with Highly Enriched Uranium and Polyethylene [Slides]

This presentation discusses Thermal/Epithermal eXperiments (TEX) in relation to integral experiments spanning a wide range of fission energy spectra utilizing existing NCSP fissile material assets, TEX-Pu for plutonium, and TEX-HEU highly enriched uranium (HEU) for highly enriched uranium. It also discusses the TEX-HEU design, the use of HEU fuel, and polyethylene parts. The experiment, executed in the Nuclear Criticality Experiment Research Center of the Nevada National Security Site is discussed, specifically how it was assembled on the Comet Universal Critical Assembly Machine. Measured quantities and various critical configurations are listed. In conclusion, the presentation states that they successfully assembled and documented the baseline TEX-HEU experiments, that six critical configurations and one reproducibility measurement were produced, and that they are compiling results to submit to the International Criticality Safety Benchmark Evaluation Project. A future experiment campaign is planned in 2021 with Hafnium as a diluent.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2020

ENDF/B-VIII.0 Augmented Covariance Data The first iteration [Slides]

Nuclear data are necessary for reliable modeling and simulation of the next generation of nuclear reactors. However, the variation in the ratio of the computed to experimental values (C/E) for certain types of nuclear systems is much less than predicted by evaluated nuclear data file (ENDF)/B covariances. Figure 1 provides an example of a set of metal-plutonium-fueled, fast-spectrum (PU-MET-FAST) integral experiments from the International Criticality Safety Benchmark Evaluation Project (ICSBEP) in the Oak Ridge National Laboratory (ORNL) VALID database. The variation in the C/E values, shown with one standard deviation error bars, is 100% covered by both the SCALE and ENDB/VIII.0 covariance data. This is due to the comparisons to integral data that are essential during the evaluation process. However, the ENDF evaluations represent uncertainties and correlations in differential data only; they do not reflect the impact of the comparison to integral data in the covariance evaluations.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

NCSP Outlook and Interest for Collaboration on HST Experiments [Slides]

The majority of the NCSP budget goes to Integral Experiments. The goal is to produce needed integral data for criticality safety needs in DOE, largely resulting in ICSBEP benchmarks. NCSP has a well defined process for allocating funding through proposals and expert review. NCSP is a fairly small program and funding is prioritized for experiments that would address DOE criticality safety needs. The majority of the currently identified DOE criticality safety needs are HEU and Pu systems. NCSP has a formal mechanism to ensure quality and benefit through the phase gates and approvals within the CED process.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Consistent $\overline{ν}$ evaluation for minor U isotopes with $\tt{CGMF}$

Following several successful prompt $\overline{ν}$ evaluations using $\tt{CGMF}$, including consistent evaluations for minor Pu isotopes, we detail in this report our efforts to perform a consistent $\overline{ν}$ evaluation for minor U isotopes during FY25. Although we have not yet produced a finalized evaluation, we present the progress that we have made towards such an evaluation for 232,233,234,236,237,239 U prompt $\overline{ν}$. Our milestone explicitly calls out evaluations for 233 U, 234 U, and 236 U, however, to better constrain the model with reliable experimental $\overline{ν}$ data, we also include 235 U and 238 U in the evaluation procedure. Then, we additionally produce evaluations for 232 U, 237 U and 239 U $\overline{ν}$ as a byproduct. Elsewhere, we will report our efforts on a stand-alone 233 U $\overline{ν}$ evaluation. This report is organized in the following manner. In Sec. 2, we briefly outline the updates to CGMF that were needed to be able to calculate all of these minor U fission reactions. The experimental data overview is given in Sec. 3. The evaluation methodology and results are presented in Secs. 4 and 5, respectively. Finally, we conclude and outline work for FY26 in Sec. 6.

07 ISOTOPE AND RADIATION SOURCES↗