Author
T.L. Markin
Bio: T.L. Markin is an academic researcher. The author has contributed to research in topics: Eutectic system & Phase rule. The author has an hindex of 1, co-authored 1 publications receiving 88 citations.
Topics: Eutectic system, Phase rule, Phase diagram
Papers
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TL;DR: The plutonium-oxygen phase diagram between PuO1·5 and PuO2 and between room temperature and 900° has been studied using a high-temperature X-ray powder-diffraction camera.
90 citations
Cited by
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TL;DR: Results show that PuO(2+x), a high-composition (x = 0.27) phase containing Pu(VI), is the stable binary oxide in air, and perplexing aspects of plutonium oxide chemistry can now be explained.
Abstract: Results show that PuO(2+x), a high-composition (x = 0.27) phase containing Pu(VI), is the stable binary oxide in air. This nonstoichiometric oxide forms by reaction of dioxide with water and by water-catalyzed reaction of dioxide with oxygen. The PuO(2) + H(2)O reaction rate is 0.27 nanomoles per meter squared per hour at 25 degrees C; the activation energy at 25 degrees to 350 degrees C is 39 kilojoules per mole. Slow kinetics and a low lattice parameter-composition dependence for fluorite-related PuO(2+x) are consistent with a failure to observe the phase in earlier studies. Perplexing aspects of plutonium oxide chemistry can now be explained.
251 citations
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TL;DR: In this paper, a thermodynamic model for the (U, Pu)O 2 oxide, the carbide fuels using the Calphad method to describe consistently both phase diagrams and thermodynamic data of the phases involved in the U-Pu-O-C system was derived.
180 citations
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TL;DR: In this paper, the electronic structure of PuO2± x was studied using first-principles quantum mechanics, realized with the self-interaction corrected local spin density method.
Abstract: The electronic structure of PuO2± x was studied using first-principles quantum mechanics, realized with the self-interaction corrected local spin density method. In the stoichiometric PuO2 compound, Pu occurs in the Pu(IV) oxidation state, corresponding to a localized f4 shell. If oxygen is introduced onto the octahedral interstitial site, the nearby Pu atoms turn into Pu(V) (f3) by transferring electrons to the oxygen. Oxygen vacancies cause Pu(III) (f5) to form by taking up electrons released by oxygen. At T = 0, the PuO2 compound is stable with respect to free oxygen, but the delicate energy balance suggests the possible deterioration of the material during long-term storage.
134 citations
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TL;DR: In this paper, the authors constructed a phase diagram between UO 1·88 U 3 O 8 and PuO 2 ǫPuO 1 ·5 for all concentrations of Pu and between room temperature and 800°C, from results obtained using a high-temperature X-ray powder diffraction camera.
104 citations