Neutron Diffraction Study of Highly Radioactive U3Si2 Reactor Fuel

1994 ◽  
Vol 373 ◽  
Author(s):  
J. W. Richardson ◽  
R. C. Birtcher ◽  
M. H. Mueller
Keyword(s):  
Neutron Diffraction ◽  
Room Temperature ◽  
Amorphous Material ◽  
Neutron Diffraction Study ◽  
General Purpose ◽  
Crystalline Lattice ◽  
Sample Container ◽  
Scattering Pattern ◽  
Nanocrystalline Particles ◽  
Mini Plate

AbstractNeutron diffraction data were collected from a highly radioactive, low-enrichment uraniumU3Si2/A1 fuel mini-plate that had been irradiated to 42% uranium burnup. The experiment was performed using the General Purpose Powder Diffractometer at IPNS. Most prominent in the diffraction pattern were the Bragg reflections from crystalline Al (fuel plate) and V (sample container). Rietveld refinement revealed a broad oscillatory signal from the U3Si2 typical of amorphous material. This “amorphous” scattering pattern has peaks at the same positions as the amorphous scattering components observed following room temperature neutron irradiation of U3Si2 powder. The irradiated U3Si2 is amorphous with a remote possibility that it consists of recrystallized nanocrystalline particles subject to the requirements that the crystallites: (i) are no larger than 100-200 Å in size, and (ii) possess a crystalline lattice which is distorted relative to the unirradiated material.

A neutron diffraction study of potassium dihydrogen phosphate by Fourier synthesis

1953 ◽  
Vol 220 (1142) ◽  
pp. 397-421 ◽  
Keyword(s):  
Neutron Diffraction ◽  
Room Temperature ◽  
Potassium Dihydrogen Phosphate ◽  
Neutron Diffraction Study ◽  
Data Series ◽  
Dihydrogen Phosphate ◽  
Fourier Synthesis ◽  
Potassium Dihydrogen ◽  
Atomic Nuclei ◽  
Specific Assessment

Projections of the distribution of atomic nuclei in potassium dihydrogen phosphate at room temperature have been obtained by Fourier synthesis of single-crystal neutron diffraction data. Series termination effects have been examined and corrected for, either by specific assessment of the diffraction rings or by difference syntheses. The parameters so obtained are confirmed by least-squares analyses and give a reliability index of 7%. Hydrogen peaks occur midway between two oxygen atoms and appear circular when viewed along the O—H—O bond, but elliptical when viewed across it. The PO 4 tetrahedra are much more nearly regular than previously supposed, and the O—H—O bonds are inclined at not more than ½º to the xy -plane.

Neutron Diffraction Study of Duplex Stainless Steel during Loading at 200°C

2008 ◽  
Vol 571-572 ◽  
pp. 175-180
Author(s):  
Rim Dakhlaoui ◽  
Andrzej Baczmanski ◽  
Chedly Braham ◽  
Sebastian Wroński ◽  
Krzysztof Wierzbanowski ◽  
...  
Keyword(s):  
Neutron Diffraction ◽  
Room Temperature ◽  
Compressive Loading ◽  
Diffraction Method ◽  
Neutron Diffraction Study ◽  
Shear Stresses ◽  
Duplex Steel ◽  
Consistent Model ◽  
Influence Of Temperature On ◽  
Tension And Compression

In this work, the influence of temperature on the mechanical properties of duplex steel is studied by performing monotonic “in situ” tension and compression at 200oC. The lattice strains in both phases were measured using the time-of-flight neutron diffraction method (at the ISIS spallation neutron source, STFC Rutherford Appleton Laboratory, UK). A thermal-elastic selfconsistent model was used to predict the expansion of the interplanar spacings during heating to 200°C. Subsequently, the variation of phase stresses during tensile and compressive loading at room temperature (20°C) and at 200°C were theoretically calculated by the elastoplastic self-consistent model. Comparing the model data with experimental results the critical resolved shear stresses and work hardening parameters were determined individually in each phase of the DSS. Finally, the yield stresses in each phase of the studied steel have been estimated. It was found that both yield points (of austenite and ferrite) are lower at 200°C than those at room temperature.

Neutron Diffraction Study on Intermetallic Er5Mg24 and Tm5Mg24

2004 ◽  
Vol 443-444 ◽  
pp. 263-266 ◽  
Author(s):  
Wolfgang Schäfer ◽  
K.H.J. Buschow
Keyword(s):  
Neutron Diffraction ◽  
Powder Diffraction ◽  
Room Temperature ◽  
Neutron Diffraction Study ◽  
Neutron Powder Diffraction ◽  
Magnetic Exchange ◽  
Lattice Constants ◽  
Group I ◽  
Temperature Lattice ◽  
Curie Temperatures

Neutron powder diffraction on the binary intermetallics Er5Mg24 and Tm5Mg24 confirms their isostructural and pure crystallization in the Ti5Re24-type structure (space group I 4 3m, Z = 2)with rare earths located in 2a(0,0,0) and 8c(x,x,x) and Mg in two different 24g(x,y,x) sites. Room temperature lattice constants are 11.263(2) Å and 11.215(1) Å for the Er and Tm compound, respectively. Atomic positions have been refined. Both compounds order ferromagnetically below Curie temperatures of 17.5(5) K and 7.5(5) K for Er5Mg24 and Tm5Mg24, respectively. The magnitudes of the Er moments at 4.2 K are 7.5(2) µB and 4.4(2)µB on the 2a and the 8c sites, respectively. The Tm moments which have been refined from 2 K measurements amount to 3.0(3)µB and 2.8(2) µB, respectively. The temperature dependencies of the magnetic Bragg intensities reveal distinct deviations from Brillouin curves for J = 15/2 (Er) and J = 6 (Tm) systems and indicate a complex magnetic exchange.

A neutron diffraction study of room-temperature monoclinic Kd2PO4

1975 ◽  
Vol 34 (1) ◽  
pp. 175-177 ◽  
Author(s):  
F.R. Thornley ◽  
R.J. Nelmes ◽  
K.D. Rouse
Keyword(s):  
Neutron Diffraction ◽  
Diffraction Study ◽  
Room Temperature ◽  
Neutron Diffraction Study

scholarly journals Study of hydrogen storage materials by neutron powder diffraction

2014 ◽  
Vol 70 (a1) ◽  
pp. C939-C939
Author(s):  
Jacques Huot ◽  
Catherine Gosselin ◽  
Thomas Bibienne ◽  
Roxana Flacau
Keyword(s):  
Neutron Diffraction ◽  
Hydrogen Storage ◽  
Room Temperature ◽  
Cast Alloy ◽  
Metal Hydrides ◽  
Structural Difference ◽  
Neutron Diffraction Study ◽  
Point Of View ◽  
Scattering Lengths ◽  
The One

Metal hydrides are interesting materials from a fundamental as well as practical point of view. Hydrogen storage applications have been the main driving force of research on these materials but lately uses such as thermal storage are considered. In this presentation we will review the use of neutron diffraction for the development of new metal hydrides. Two systems will be presented: BCC solid solution alloys and FeTi alloy. Ti-based BCC solid solutions are promising material for hydrogen storage applications which need high volumetric capacity and room temperature operation. One system that has been considered is Ti-V-Cr. Using only X-ray diffraction for structural identification does not provide information about hydrogen localization. Therefore, neutron diffraction is essential for complete determination of this class of hydrides. We will present examples of Ti-V-Cr compounds doped with Zr-Ni alloy. The peculiarity of this type of alloy is that, for neutron diffraction, the scattering lengths of the elements almost cancel. Therefore, the neutron pattern of as-cast alloy shows very small Bragg peaks but the advantage is that the hydride for is very easy to see and analyze. Another good candidate for hydrogen storage applications is the intermetallic compound TiFe which operates at around room temperature (RT) under mild pressure conditions. However one disadvantage of TiFe alloy synthesized by conventional metallurgical method is its poor activation characteristics. The alloy reacts with hydrogen only after complicated activation procedure involving exposure to high temperature (~4000C) and high pressure for several days. Recently we found that by doping this alloy with Zr and Zr7Ni10 the activation could be easily done at room temperature. We present here a neutron diffraction study of these compounds that shows the structural difference between the activated compound and the one cycled under hydrogen.

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