Dilatometry and differential thermal analysis of americium metal

Rose, Robert L.; Kelley, Robin D. G.; Lesuer, D.R.

doi:10.1016/0022-3115(79)90107-7

Cited by 11 publications

(4 citation statements)

References 4 publications

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“…Several researchers have reported that the density of α-Am is ~13.6 g/cm 3 at room temperature [201,208,416]. This value is slightly higher than that measured by Rose et al (13.38 g/cm 3 ) from a sample that had up to 0.4 wt% of measured impurities [204].…”

Section: Room-temperature Densitymentioning

confidence: 60%

“…The crystallographic characteristics of the generally recognized solid Am phases are:  -Am, dhcp (space group P6 3 /mmc), a = 3.4681 Å, c = 11.241 Å at 20 °C [201]  -Am, fcc (space group𝐹𝑚3 ̅ 𝑚), a = 4.894 Å [201]  γ-Am, assumed to be bcc (space group 𝐼𝑚3 ̅ 𝑚) by analogy to the early lanthanides [4]. This phase is known from dilatometry and differential thermal analysis data (e.g [203][204][205][206]). A recent paper indicating that γ-Am has space group Fm3m and lattice parameter a = 4.894 Å [196 Table 2] is probably mislabeled data from β-Am.…”

Section: Phasesmentioning

confidence: 99%

“…The existence of other Am phases has been suggested as a result of thermophysical analyses [204,207], but without information on crystal structures. In particular, a phase with a dhcp structure and lattice parameters significantly larger than those of α-Am has been identified by several researchers using X-ray diffraction data [208][209][210].…”

Section: Phasesmentioning

confidence: 99%

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FCRD Advanced Reactor (Transmutation) Fuels Handbook

Janney

Papesch

2016

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Transmutation of minor actinides such as Np, Am, and Cm in spent nuclear fuel is of international interest because of its potential for reducing the long-term health and safety hazards caused by the radioactivity of the spent fuel. One important approach to transmutation (currently being pursued by the DOE Fuel Cycle Research & Development Advanced Fuels Campaign) involves incorporating the minor actinides into U-Pu-Zr alloys, which can be used as fuel in fast reactors. U-Pu-Zr alloys are well suited for electrolytic refining, which leads to incorporation rare-earth fission products such as La, Ce, Pr, and Nd. It is, therefore, important to understand not only the properties of U-Pu-Zr alloys but also those of U-Pu-Zr alloys with concentrations of minor actinides (Np, Am) and rare-earth elements (La, Ce, Pr, and Nd) similar to those in reprocessed fuel.

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Section: Room-temperature Densitymentioning

confidence: 60%

Section: Phasesmentioning

confidence: 99%

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FCRD Advanced Reactor (Transmutation) Fuels Handbook

Janney

Papesch

2016

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“…(7) has confirmed a previous observation of a fee phase (13) as the high temperature form of Pa; the bcc form predicted (14) by extrapolating the variation of the expansion coefficients in the different lattice directions was never detected. Dilatometry and differential thermal analysis were used in an attempt to clear up controversy in the literature on the polymorphism of Am (15) . There seem to be at least 3 different phases, the dhcp ("a" -) phase stable up to about 650°C, a " g"-phase" existing until 1050°C, followed by the high temperature form between 1050°C and the melting point.…”

Section: Reduction By La 1000°cmentioning

confidence: 99%

Actinides: d-or ƒ—Transition Metals?

Müller

1980

Lanthanide and Actinide Chemistry and Spectroscopy

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The chemical and physical properties of elements depend on their electron configuration and, in particular, on the number and the nature of the bonds formed by the outer ("valence") electrons. Crystal structure and lattice parameters, as well as thermodynamic and electronic properties reflect the nature and strength of these chemical bonds. For instance, the crystal radii of elements are a function of their atomic number and oxidation number, hence of their electron configuration in the solid state. Thermodynamics give access to the strength of the bond: melting temperatures, vapour pressures and enthalpies of dissolution are measures of the tendency of the elemental crystal to pass into the liquid, gaseous or solution phase. Specific heat and electrical resistivity as well as magnetic susceptibility furnish additional information on the electrons, their energy and their participation in bonding. Finally, spectroscopy (optical, photoemission) can provide information on the mixing of different quantum characters in the bond (hybridization). Actinide elements (Z = 89 -103) include the heaviest natural and most of the synthetic transuranium elements. They form a series of transition elements, characterized by the filling of an inner -the 5f-electron shell. The elements from Ac (Z = 89) to Es (Z = 99) are available in quantities sufficient for solid state studies. Elemental actinides are metallic. The methods of metal preparation and characterization have been improved to yield samples of known purity and crystal structure, sometimes in the form of single crystals. Recent measurements of structural, thermodynamic and electronic properties have emphasized elements in the beginning and in the centre of the actinide series. In the following, methods for preparation, purification and characterization of actinide. metals are reviewed. Properties are presented, the theoretical interpretation of which underlines the special nature of the actinides in comparison with d or 4f (lanthanide) transition metals. 0-8412-0568-X/80/47-131-183$05.00/0

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