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Developments in the TEM (Transmission Electron Microscopy) examination of Pu and Pu alloys

Description: Microstructural characterization of plutonium utilizing Transmission Electron Microscopy (TEM), has previously been shown to be difficult because of the extreme toxicity and high oxidation rate of plutonium metal. Recent developments in plutonium sample preparation have shown that TEM foils of both alpha and delta phases may be prepared without the use of inert atmospheric systems on complex preparation devices. Using standard electropolishing techniques, samples may be produced which yield imp… more
Date: January 1, 1987
Creator: Zocco, T.G. & Rohr, D.L.
Partner: UNT Libraries Government Documents Department
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Application of transmission electron microscopy to splat-cooled plutonium alloys

Description: Plutonium alloy foils, thin enough for transmission electron microscopy (TEM), were made by rapidly quenching small specimens from the melt in a ''gun''-type, splat-cooling device. Microstructures in selected regions of the nonequilibrium alloys thus produced are illustrated and discussed. (auth)
Date: February 1, 1976
Creator: Rohr, D. L. & Elliott, R. O.
Partner: UNT Libraries Government Documents Department
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Spontaneous fragmentation of an alpha-active ceramic: a mechanism for dispersion of solid waste

Description: Studies underway to characterize spontaneous fragmentation in /sup 238/PuO/sub 2/ and to determine the mechanism(s) responsible are reported. Results reported here show that: spontaneous fragmentation of /sup 238/PuO/sub 2/ generates a wide range of particle sizes, from a few mm to 1000 A or less; the phenomenon may continue with time or may saturate, depending on starting material; the magnitude of the effect is dependent on storage environment. Neither thermal stresses nor lattice damage appe… more
Date: January 1, 1980
Creator: Clinard, F. W. Jr. & Rohr, D. L.
Partner: UNT Libraries Government Documents Department
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Structural damage in a self-irradiated zirconolite-based ceramic

Description: The zirconolite phase of SYNROC nuclear waste was fabricated with 5 mol % /sup 238/PuO/sub 2/ substituted for a like amount of ZrO/sub 2/, in order to induce self-irradiation damage. The resulting product exhibited a matrix of monoclinic zirconolite containing approx. 3.8 mol % PuO/sub 2/ along with roughly 20 vol % of the cubic polymorph with approximately twice the PuO/sub 2/ content of the matrix. After a dose of 2.1 x 10/sup 25/ ..cap alpha.. decays/m/sup 3/ at room temperature (800 days' s… more
Date: January 1, 1983
Creator: Clinard, F.W. Jr.; Rohr, D.L. & Roof, R.B.
Partner: UNT Libraries Government Documents Department
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Mechanical properties of /sup 238/PuO/sub 2/

Description: The mechanical properties of /sup 238/PuO/sub 2/ have been examined in the Los Alamos Scientific Laboratory mechanical test facility built to handle ..cap alpha..-radioactive materials. Compression tests were conducted as a function of temperature, strain rate, grain size, density, and storage time. At temperatures less than or equal to 1400/sup 0/C, test specimens of /sup 238/PuO/sub 2/ exhibit pseudobrittle behavior due to internal cracks. Plastic deformation is ''localized'' at the crack tip… more
Date: April 1, 1977
Creator: Petrovic, J. J.; Hecker, S. S.; Land, C. C. & Rohr, D. L.
Partner: UNT Libraries Government Documents Department
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Effect of storage temperature on self-irradiation damage of /sup 238/Pu-substituted zirconolite

Description: /sup 238/Pu-substituted cubic zirconolite (CaPuTi/sub 2/O/sub 7/) was stored at ambient temperature, 575/sup 0/ K, and 875/sup 0/ K until alpha decay doses of 2.4 to 3.6 x 10/sup 25//m/sup 3/ had been accumulated. The ambient temperature material swelled to a saturation value of 5.5 vol %, and the originally crystalline structure was transformed to one with an amorphous matrix and small domains that had retained their crystallinity. At 575/sup 0/ K, lesser amounts of swelling (4.1 vol %) and tr… more
Date: January 1, 1982
Creator: Clinard, F. W.; Peterson, D. E.; Rohr, D. L.; Roof, R. B. & Hobbs, L. W.
Partner: UNT Libraries Government Documents Department
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Alpha decay self-damage in cubic and monoclinic zirconolite

Description: Samples of primarily-monoclinic /sup 238/Pu-doped zirconolite were stored at ambient temperature to allow accumulation of alpha decay self-damage to a dose of 1 x 10/sup 24/ ..cap alpha../m/sup 3/ (equivalent to a SYNROC age of approx. 10/sup 3/y). Bulk swelling reached 2.3 vol% with no tendency toward saturation, a damage response similar to that observed for cubic Pu-doped zirconolite. X-ray volumetric swelling at 4 x 10/sup 24/ ..cap alpha../m/sup 3/ was 1 vol%, considerably less than that f… more
Date: January 1, 1981
Creator: Clinard, F.W. Jr.; Land, C.C.; Peterson, D.E.; Rohr, D.L. & Roof, R.B.
Partner: UNT Libraries Government Documents Department
open access

Structural performance of ceramics in a high-fluence fusion environment

Description: The ceramics MgAl/sub 2/O/sub 4/, Al/sub 2/O/sub 3/ (single crystal), Si/sub 3/N/sub 4/, and a SiC/graphite laminate were irradiated to approx. 2 x 10/sup 26/ n/m/sup 2/ (E > 0.1 MeV) at 680 and 815K. Spinel exhibited near-zero dimensional change, while Al/sub 2/O/sub 3/ and Si/sub 3/N/sub 4/ swelled approx. 3 vol % and 1 vol % respectively. Strength of MgAl/sub 2/O/sub 4/ was increased, while strength of Al/sub 2/O/sub 3/ and Si/sub 3/N/sub 4/ were not greatly altered. The SiC/graphite composi… more
Date: January 1, 1983
Creator: Clinard Jr., F. W.; Hurley, G. F.; Hobbs, L. W.; Rohr, D. L. & Youngman, R. A.
Partner: UNT Libraries Government Documents Department
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