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Author Lawson, A. C. ♦ Cort, B. ♦ Roberts, J. A. ♦ Bennett, B. I. ♦ Richardson, J. W. (Jr.)
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ PHYSICS ♦ NEUTRON DIFFRACTION ♦ THORIUM-ALPHA ♦ NEPTUNIUM-ALPHA ♦ URANIUM-ALPHA ♦ PLUTONIUM-ALPHA ♦ PLUTONIUM-DELTA ♦ CRYSTAL STRUCTURE ♦ TEMPERATURE DEPENDENCE ♦ DEBYE-WALLER FACTOR ♦ THERMAL EXPANSION
Abstract For the past few years the authors have been applying the techniques of neutron powder diffraction to questions arising from the peculiar properties of the light actinide metals. The peculiar properties include complicated crystal structures, leading to complex phase diagrams; anomalous elastic and thermal expansion behavior; and surprisingly low melting points, especially for plutonium. The authors have made neutron diffraction studies of {alpha}-thorium, {alpha}-neptunium, {alpha}-uranium, and {alpha}- and {delta}-plutonium. A great deal has been learned from a study of the temperature dependence of the thermal vibrations of the light actinides. These can be determined using neutron diffraction to measure the Debye-Waller factors in powder diffraction experiments. The same neutron diffraction experiments also give information on the linear coefficient of thermal expansion {alpha}. This quantity is also strongly temperature dependent. Other neutron diffraction work is in progress, including attempts to solve some of the unknown alloy structures of Pu, and texture analysis via pole-figure measurements. The texture measurements are of particular interest, given the elastic anisotropy. High-quality data on Pu require the use of the nonabsorbing {sup 242}Pu isotope, and this is a disadvantage. However, the high penetration of neutrons into most materials means that many safety problems can be solved by encapsulation of the radioactive material in V or other metal.
ISSN 0003018X
Educational Use Research
Learning Resource Type Article
Publisher Date 1998-12-31
Publisher Place United States
Journal Transactions of the American Nuclear Society
Volume Number 79
Technical Publication No. CONF-981106-


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