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PREPARATION AND CHARACTERIZATION OF THE POLYMORPHS OF UO$sub 3$

Description: Six polymorphs of UO/sup 3/ were prepared and were identified by x-ray diffraction techniques. Differential thermal techniques were used to study the decompositions of the polymorphs to U/sub 3/O/sub 8/ and to investigate the modes of formation of the polymorphs from the hydrates of UO/sub 3/. (auth)
Date: August 1, 1962
Creator: Cornman, W.R. Jr.
Partner: UNT Libraries Government Documents Department

PROBLEMS OF REFINING URANIFEROUS RESIDUES. Progress Report for May 1953

Description: The applicability and refinement of various procedures for the treatment and digestion of C-slags and other uraniferous residues for recovery of U values were studied. The recovery of U from BFC-6 was investigated, placing emphasis on procedures which will not chemically alter the Cu and Sn media. Methods of U recovery from various residues resulting from Na/sub 2/CO/sub 3/ digestion of miscellaneous U-bearing materials, to reduce the U/sub 3/C/sub 8/ content below 0.05%, are discussed. (W.L.H.)
Date: June 15, 1953
Creator: Fleck, H. & Summer, J.E.
Partner: UNT Libraries Government Documents Department

Uranium oxide activation cost study

Description: Owing to continuous uranyl nitrate calcining facilities at Hanford, the reactivity of the A oxide produced was reduced, with lower conversion to UF{sub 4}. A process design was developed for increasing the A{sub 3}O{sub 8} activity by fluidized-bed reduction to UO{sub 2} and reoxidation to A{sub 3}O{sub 8}. Justification for the installation would be in the $250,000 to $300,000 saved in not needing additional fluorine cells and $310,000 per year operating cost savings. The installation would cost $700,000 or $860,000; operating cost would be $270,000 per year. It was concluded that a full-scale process cannot be justified at the time of the study.
Date: April 23, 1957
Creator: McKee, R. W.
Partner: UNT Libraries Government Documents Department

Dissolving uranium oxide--aluminum fuel

Description: The dissolution of aluminum-clad uranium oxide-aluminum fuel was studied to provide basic data for dissolving this type of enriched uranium fuel at the Savannah River Plant. The studies also included the dissolution of a similar material prepared from scrap uranium oxides that were to be recycled through the solvent extraction process. The dissolving behavior of uranium oxide-aluminum core material is similar to that of U-Al alloy. Dissolving rates are rapid in HNO/sub 3/-Hg(NO/sub 3/)/sub 2/ solutions. Irradiation reduce s the dissolving rate and increases mechanical strength. A dissolution model for use in nuclear safety analyses is developed, . based on the observed dissolving characteristics. (auth)
Date: November 1, 1973
Creator: Perkins, W.C.
Partner: UNT Libraries Government Documents Department

STABILIZING EFFECTS OF OXIDE ADDITIONS TO URANIUM OXIDE

Description: An investigation of the stabilizing influence of oxide additions to uranium oxide was continued. These additions are employed to eliminate the phase transformation to U/sub 3/O?sub 8/ which occurs when UO/sub 2/ is exposed to an oxidizing environment at elevated temperatures and to reduce the volatility or transpiration losses of uranium oxide which become appreciable in air at temperatures in excess of 1200 deg C. The results show that CaO may be successfully employed in partial substitution for La/sub 2/O/sub 3/ and Y/sub 2/O/ sub 3/. The resulting solid solutions exhibited high-temperature stability comparable to that of the "binary" solid solutions of UO/sub 2/ containing La/sub 2/O/sub 3/ or Y/sub 2/O/sub 3/. On the basis of thes e and other results some alternative approaches appear possible to reduce the amount and cross section of additive required for stabilization. (auth)
Date: September 13, 1960
Creator: Wilson, W.B. & Gerds, A.F.
Partner: UNT Libraries Government Documents Department

Shuffler bias corrections using calculated count rates

Description: Los Alamos National Laboratory has two identical shufflers that have been calibrated with a dozen U{sub 3}O{sub 8} certified standards from 10 g {sup 235}U to 3600 g {sup 235}U. The shufflers are used to assay a wide variety of material types for their {sup 235}U contents. When the items differ greatly in chemical composition or shape from the U{sub 3}O{sub 8} standards a bias is introduced because the calibration is not appropriate. Recently a new tool has been created to calculate shuffler count rates accurately, and this has been applied to generate bias correction factors. The tool has also been used to verify the masses and count rates of some uncertified U{sub 3}O{sub 8} standards up to 8.0 kg of {sup 235}U which were used to provisionally extend the calibration beyond the 3.6 kg of {sup 235}U mass when a special need arose. Metallic uranium has significantly different neutronic properties from the U{sub 3}O{sub 8} standards and measured count rates from metals are biased low when the U{sub 3}O{sub 8} calibration is applied. The application of the calculational tool to generate bias corrrections for assorted metals will be described. The accuracy of the calculational tool was verified using highly enriched metal disk standards that could be stacked to form cylinders or put into spread arrays.
Date: April 1, 2001
Creator: Rinard, Phillip M.; Hurd, J. R. (Jon R.) & Hsue, F. (Faye)
Partner: UNT Libraries Government Documents Department

REACTIVITY OF CERTAIN URANIUM OXIDES WITH ALUMINUM. Terminal Report

Description: The reaction between uranium dioxide and aluminum has been studied at 600 deg C and below. At 600 deg C the visible reaction occurred within a few hours, while, for example, at 500 deg C and below, the specimens had to be at temperature for several days in order to show signs of any reaction. The method of manufacture of uranium dioxide had a pronounced effect on its compatibility. Granulated and high-fired oxides showed lowest, and the steam-treated oxide showed maximum, reactivity. The fact that finer oxide powder partlcles react faster than coarse ones was according to expectations. Mallinckrodt U/sub 3/O/ sub 8/ powder of very fine particle size reacted severely with aluminum during a 1 1/2-hr test at 610 deg C. (auth)
Date: February 10, 1958
Creator: Eiss, A.L.
Partner: UNT Libraries Government Documents Department