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At least 559 records · Page 31
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CePuCo4 by Materials Project

PuCeCo4 is Hexagonal Laves-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Pu is bonded in a 12-coordinate geometry to four equivalent Ce and twelve equivalent Co atoms. All Pu–Ce bond lengths are 3.01 Å. All Pu–Co bond lengths are 2.88 Å. Ce is bonded in a 12-coordinate geometry to four equivalent Pu and twelve equivalent Co atoms. All Ce–Co bond lengths are 2.88 Å. Co is bonded to three equivalent Pu, three equivalent Ce, and six equivalent Co atoms to form a mixture of edge, corner, and face-sharing CoCe3Pu3Co6 cuboctahedra. There are three shorter (2.42 Å) and three longer (2.49 Å) Co–Co bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2Br2O by Materials Project

Pu2OBr2 is Cyanogen Chloride-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Pu2OBr2 cluster. Pu is bonded in a linear geometry to one O and one Br atom. The Pu–O bond length is 2.05 Å. The Pu–Br bond length is 2.64 Å. O is bonded in a linear geometry to two equivalent Pu atoms. Br is bonded in a single-bond geometry to one Pu atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2SiO10 by Materials Project

Pu2SiO10 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Pu is bonded to seven O atoms to form distorted PuO7 pentagonal bipyramids that share corners with two equivalent SiO4 tetrahedra, edges with two equivalent PuO7 pentagonal bipyramids, and an edgeedge with one SiO4 tetrahedra. There are a spread of Pu–O bond distances ranging from 1.78–2.43 Å. Si is bonded to four equivalent O atoms to form SiO4 tetrahedra that share corners with four equivalent PuO7 pentagonal bipyramids and edges with two equivalent PuO7 pentagonal bipyramids. All Si–O bond lengths are 1.64 Å. There are three inequivalent O sites. In the first O site, O is bonded in a single-bond geometry to one Pu atom. In the second O site, O is bonded in a 1-coordinate geometry to two equivalent Pu and one Si atom. In the third O site, O is bonded in a single-bond geometry to one Pu atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CePuFe4 by Materials Project

PuCeFe4 is Hexagonal Laves-derived structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Pu is bonded in a 12-coordinate geometry to four equivalent Ce and twelve equivalent Fe atoms. All Pu–Ce bond lengths are 3.03 Å. All Pu–Fe bond lengths are 2.90 Å. Ce is bonded in a 12-coordinate geometry to four equivalent Pu and twelve equivalent Fe atoms. All Ce–Fe bond lengths are 2.90 Å. Fe is bonded to three equivalent Pu, three equivalent Ce, and six equivalent Fe atoms to form a mixture of face, edge, and corner-sharing FeCe3Pu3Fe6 cuboctahedra. There are three shorter (2.45 Å) and three longer (2.49 Å) Fe–Fe bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2HgGe by Materials Project

Pu2HgGe is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pu is bonded in a body-centered cubic geometry to four equivalent Hg and four equivalent Ge atoms. All Pu–Hg bond lengths are 3.12 Å. All Pu–Ge bond lengths are 3.12 Å. Hg is bonded in a body-centered cubic geometry to eight equivalent Pu atoms. Ge is bonded in a body-centered cubic geometry to eight equivalent Pu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on PuPbAu2 by Materials Project

PuAu2Pb is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pu is bonded in a body-centered cubic geometry to eight equivalent Au and six equivalent Pb atoms. All Pu–Au bond lengths are 3.10 Å. All Pu–Pb bond lengths are 3.58 Å. Au is bonded in a body-centered cubic geometry to four equivalent Pu and four equivalent Pb atoms. All Au–Pb bond lengths are 3.10 Å. Pb is bonded in a 8-coordinate geometry to six equivalent Pu and eight equivalent Au atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2SbAu by Materials Project

Pu2AuSb is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pu is bonded in a body-centered cubic geometry to four equivalent Au and four equivalent Sb atoms. All Pu–Au bond lengths are 3.22 Å. All Pu–Sb bond lengths are 3.22 Å. Au is bonded in a body-centered cubic geometry to eight equivalent Pu atoms. Sb is bonded in a body-centered cubic geometry to eight equivalent Pu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2I2O by Materials Project

Pu2OI2 is Cyanogen Chloride-like structured and crystallizes in the tetragonal P4/mmm space group. The structure is zero-dimensional and consists of one Pu2OI2 cluster. Pu is bonded in a distorted linear geometry to one O and one I atom. The Pu–O bond length is 2.02 Å. The Pu–I bond length is 2.85 Å. O is bonded in a linear geometry to two equivalent Pu atoms. I is bonded in a single-bond geometry to one Pu atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2SnHg by Materials Project

Pu2HgSn is Heusler structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Pu is bonded in a body-centered cubic geometry to four equivalent Hg and four equivalent Sn atoms. All Pu–Hg bond lengths are 3.28 Å. All Pu–Sn bond lengths are 3.28 Å. Hg is bonded in a body-centered cubic geometry to eight equivalent Pu atoms. Sn is bonded in a body-centered cubic geometry to eight equivalent Pu atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2SbTe2 by Materials Project

Pu2SbTe2 crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. Pu+3.50+ is bonded to two equivalent Sb3- and five equivalent Te2- atoms to form a mixture of distorted edge, corner, and face-sharing PuSb2Te5 pentagonal bipyramids. Both Pu–Sb bond lengths are 3.25 Å. There are four shorter (3.10 Å) and one longer (3.19 Å) Pu–Te bond lengths. Sb3- is bonded in a 4-coordinate geometry to four equivalent Pu+3.50+ atoms. Te2- is bonded to five equivalent Pu+3.50+ atoms to form a mixture of distorted edge and corner-sharing TePu5 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Li3Pu by Materials Project

Li3Pu crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded in a 12-coordinate geometry to four equivalent Li and four equivalent Pu atoms. All Li–Li bond lengths are 3.11 Å. All Li–Pu bond lengths are 3.30 Å. In the second Li site, Li is bonded in a square co-planar geometry to four equivalent Pu atoms. All Li–Pu bond lengths are 3.11 Å. Pu is bonded to twelve Li atoms to form a mixture of edge, face, and corner-sharing PuLi12 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pu2Re3Si5 by Materials Project

Pu2Re3Si5 crystallizes in the tetragonal P4/mnc space group. The structure is three-dimensional. Pu+3.50+ is bonded in a 9-coordinate geometry to nine Si4- atoms. There are a spread of Pu–Si bond distances ranging from 2.88–3.21 Å. There are two inequivalent Re+4.33+ sites. In the first Re+4.33+ site, Re+4.33+ is bonded to six Si4- atoms to form a mixture of distorted corner, edge, and face-sharing ReSi6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are a spread of Re–Si bond distances ranging from 2.45–2.54 Å. In the second Re+4.33+ site, Re+4.33+ is bonded in a distorted hexagonal planar geometry to six Si4- atoms. There are four shorter (2.46 Å) and two longer (2.70 Å) Re–Si bond lengths. There are three inequivalent Si4- sites. In the first Si4- site, Si4- is bonded in a 9-coordinate geometry to three equivalent Pu+3.50+, four Re+4.33+, and two equivalent Si4- atoms. Both Si–Si bond lengths are 2.59 Å. In the second Si4- site, Si4- is bonded in a 11-coordinate geometry to four equivalent Pu+3.50+, three Re+4.33+, and four Si4- atoms. Both Si–Si bond lengths are 2.70 Å. In the third Si4- site, Si4- is bonded in a 9-coordinate geometry to four equivalent Pu+3.50+, four equivalent Re+4.33+, and one Si4- atom. The Si–Si bond length is 2.42 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Post-irradiation examinations of annular mixed oxide fuels with average burnup 4 and 5% FIMA

In this paper, we present post-irradiation examination results on two type of annular mixed oxide fuel pins irradiated in the Fast Flux Test Facility (FFTF) sodium cooled reactor to an average burnup between 4% and 5% fission of initial heavy atom (FIMA). The pins differed only from the initial Pu content, which was 22 wt% and 26 wt%, respectively. The overall performance of the pins was excellent, in line with previous historical results. The pins with higher Pu content experienced higher irradiation temperatures which influenced the fission gas release, fuel swelling, and Cs distribution compared to the other pins. All the post-irradiation examinations results are discussed against the irradiation parameters. In particular, the pins with higher initial Pu content, i.e., 26 wt%, experienced higher power that resulted in enhanced fission gas release compared to the other two pins with 22 wt% initial Pu content. For the pins with higher fission gas release, onset of Cs redistribution was observed. The two pins that had lower initial Pu content and burnup showed a Cs axial distribution similar to the as-produced one.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

The calculation of light element impurity (α, n) yield curves in a PuO 2 matrix and associated specific yield coefficients: Influence of the reaction cross sections

Most of the Pu separated from irradiated commercial nuclear fuel is stored as PuO 2 . The primary quantitative nondestructive measurement technique used to verify the amount of Pu in storage containers is passive neutron correlation counting. An important physical property of the oxide material is the ratio, α, of the rate of (α, n) neutrons produced inside the item to the rate of neutrons produced by spontaneous fission. This ratio influences the precision of the correlated counting method and affects the interpretation of the data because of how it changes both the primary total neutron production rate and the rate of induced fission events taking place inside the item. In addition to the main O(α, n) contribution, additional contributions come from α-particle interactions with light element impurities that are inevitably present. In this work, we calculate specific (α, n) yield coefficients, expressed in units of neutrons per second per gram of α-emitting nuclide per part per million by mass of the specified impurity element distributed in a pure PuO 2 matrix, for some key α-emitting actinides commonly present in reprocessed Pu ( 238–242 Pu+ 241 Am). These coefficients are directly applicable to nuclear safeguards verification work in which the α ratio is often calculated from the Pu-isotopic composition and chemical information obtained by other means. Further, they also provide a convenient up-to-date reference set against which values generated by other methods can be compared. Results are presented for impurities with atomic number from 3 to 17 inclusive, plus K and Fe. In most cases, these coefficients are not expected to change by more than 5%–10% at any time in the future. However, as new data become available, changes as large as 20% may be needed for some targets (e.g., F). The present yield calculations are limited by the general shortage of quality experimental total (α, n) reaction cross section data, which, together with unexplained variation between determinations, means that an objective and coherent evaluation is not possible. The situation is even less satisfactory for the partial differential cross section needed to calculate neutron spectra.

(𝛼, n) reactions↗
DOE OSTI2025

Chemometrics and visible diffuse reflectance spectroscopy to classify plutonium dioxide

Diffuse reflectance (DR) spectra in the Vis-NIR (∼380–1050 nm) region were acquired for a series of PuO 2 samples with a spot size of about 10 × 10 μm. Two batches of six PuO 2 samples, synthesized approximately 7.5 months apart, were prepared using both Pu(III) and Pu(IV) oxalate precursors at three distinct calcination temperatures (450, 650, and 950 °C). This yielded a total of 12 PuO 2 samples and 433 DR spectra. The DR spectrum of PuO 2 contained numerous peaks in the visible region, and characteristic features were identified with respect to calcination temperature and chemistry. A distinct peak multiplet near 615 nm was observed for samples prepared at low calcination temperatures, and a peak near 660 nm was observed for higher calcination temperatures. A multivariate classification strategy based on principal component analysis (PCA) was developed to distinguish PuO 2 calcination temperatures of 450, 650, and 950 °C with 100 % accuracy. Classification results also indicate the potential to distinguish chemical processing history (i.e., Pu(III) or Pu(IV)) based on the spectra with 72 % accuracy based on k-nearest neighbors applied to the PCA scores. Partial least squares discriminant analysis was used to identify variation among batches with 88 % accuracy and found that peaks near 669, 681, 811, and 970 nm were the most useful for predicting the batch identity. Here, this work demonstrates how micro-diffuse reflectance spectroscopy and chemometrics can be used to classify PuO 2 processing history based on Vis-NIR spectral features. Combining the chemometric approach with mapping sequences could provide a rapid, nondestructive approach to classify Pu oxide materials for environmental, forensics, and nonproliferation applications.

Actinide↗
DOE OSTI2026

Accessibility and Reactivity of Pentavalent Plutonium under Alkaline Conditions

Plutonium exhibits a particularly complex and rich aqueous chemistry due to a dynamic redox equilibrium that can result in the coexistence of four different oxidation states in aqueous solution. Within this equilibrium, pentavalent plutonium is among the most soluble and dominant oxidation states of Pu in neutral to alkaline aqueous solutions of relevance to environmental chemistries and the extreme chemical environments encountered in high-level radioactive wastes. Despite this, the fundamental chemistry of Pu­(V) under such conditions remains poorly understood. Here, in this study, we demonstrate the redox accessibility of Pu­(V) in alkaline media based on the observations of an electrochemically reversible Pu­(VI/V) couple at E 1/2 = 0.19 V vs Hg/HgO (0.29 V vs NHE), allowing us to electrolytically generate Pu­(V) in alkaline solution. These Pu­(V) solutions remained stable under ambient conditions for at least 9 days before precipitation of crystalline Na 2 [Pu V O 2 (OH) 3 ]·2H 2 O, the first structurally characterized Pu­(V) hydroxide. The modest potential of the Pu­(VI/V) redox couple allowed us to reproduce Na 2 [Pu V O 2 (OH) 3 ]·2H 2 O synthetically as well as isolate two additional novel Pu­(V)-bearing hydroxide phases Na­[Pu V O 2 (OH) 2 (H 2 O)]·2.5H 2 O and K 2 [Pu V O 2 (OH) 3 ]·2H 2 O as single crystals from alkaline reactions under mild hydrothermal conditions (<200 °C) using Na 2 O 2 and KO 2 as reductants. This reactivity is rationalized and informed by our electrochemical measurements. The properties of the Pu­(V) solids were further characterized by using vibrational and optical spectroscopy.

Kravchuk, Dmytro V. [Argonne National Laboratory (↗
DOE OSTI2026

Plutonium(III) versus uranium(III) and samarium(III) in small molecule activation chemistry

We report the PuIII complex, [PuIII(CpMe4)3] (1-Pu), and demonstrate its differences in small molecule reactivity compared to the UIII and SmIII analogs, [UIII(CpMe4)3] (1-U) and [SmIII(CpMe4)3] (1-Sm), respectively. 1-Pu reductively cleaves the small molecule (PhS)2, affording a PuIII complex, [{PuIII(CpMe4)2}2(μ-SPh)2] (2-Pu), while retaining the PuIII center and eliminating (CpMe4)2 as a by-product, a fingerprint of a sterically induced reduction (SIR) reaction. Sm is often used as a surrogate for Pu, but the analogous [SmIII(CpMe4)3], (1-Sm), is unreactive. The (PhS)2 cleavage by 1-U proceeds solely via a metal-based oxidation (i.e., UIII → UIV), to form [UIV(CpMe4)3(SPh)] (3-U). Only 1-U reacts with (PhHN)2, affording the reductive cleavage product, [UIV(CpMe4)3(NHPh)] (4-U). The difference in reactivity of 1-Pu compared to complexes 1-Sm and 1-U was unexpected, and since SIR chemistry can enable complexes to participate in otherwise impossible reductive transformation of substrates, this reinforces the importance of studying small molecule reactivity with the transuranic elements.

Keener, Megan↗
DOE OSTI2021

Synthesis, characterization, and theoretical analysis of a plutonyl phosphine oxide complex

The interplay of bond strength and covalency are examined in AnO 2 Cl 2 (OPcy 3 ) 2 (An = Pu, U) complexes. The synthesis of trans-PuO 2 Cl 2 (OPcy 3 ) 2 , 1-Pu, has been carried out and confirmed by single crystal X-ray diffraction along with UV-vis-NIR, and 31 P NMR spectroscopies. Theoretical analysis finds that despite a higher calculated covalency for the Pu–Cl interaction, the Pu–OPcy 3 interaction is stronger due to the accumulation of electron density in the interatomic region. As a result, the coordination of equatorial ligands slightly decreases the strength of the Pu≡O yl interactions relative to the free gas phase (PuO 2 ) 2+ ion.

Windorff, Cory J.↗