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Effect of Alloying Constituents on Aluminum Dissolution Rates

Description: In studies of the effect of alloying elements on the rate of dissolution of Al in mercury-catalyzed nitric acid, it was observed that Co, Ni, and Si present at concentrations of 1 to 2% have significant passivating effects. Fe was slightly catalytic. Passivation due to Si was partly overcome by contacting the passive alloy with active, high-purity Al. Increased catalyst concentration improved the rates when Ni and Si were present. Neither approach was effective when Cu was the passivating element. For application to nuclear fuel reprocessing, it is suggested that for minimum reprocessing costs the potentially passive Al alloys not be used in fuel elements or that, failing this, electrochemical activation techniques be applied at the processing plant. (auth)
Date: April 15, 1963
Creator: Fletcher, R. D.; Jacobson, M. E. & Beard, H. R.
Partner: UNT Libraries Government Documents Department

Comparative Boron Isotopic Analysis

Description: S>Surface ionization results for natural boron isotopic analysis are in agreement with other recent investigations indicating a B/sup 11//B/sup 10/ atom ratio nesrer to 4.00 than the more commonly accepted value of 4.31 based on BF/ sub 3/ analysis. (auth)
Date: April 1, 1961
Creator: Goris, P.; Morgan, T. D. & Nielsen, R. A.
Partner: UNT Libraries Government Documents Department

The Dissolution of Iron and Nickel in Dilute Aqua Regia

Description: In laboratory studies the dissolution of iron in dilute nitric - hydrochloric acid mixtures shows an apparent reaction order of -0.62 with respect to HCl. No apparent order value for HNO/sub 3/ can be determined over the concentration ranges studied. Nickel dissolutions show apparent orders of 1.4 with respect to the HCl and 4.2 for HNO/sub 3/. Activation energies determined from 50 to 80 deg C are not constant, ranging from l0 to 20 kcal per mole for both metals. (arth)
Date: November 1, 1961
Creator: Cannon, R. D.
Partner: UNT Libraries Government Documents Department

Dynamic Properties of Heterogeneous Water Reactors

Description: The types of tests performed in SPERT-I, and the tests proposed for SPERT-II and -III, are described. These reactors are described, and factors influencing their dynamic behavior are discussed. The tests are classed as static, step, ramp, and oscillatory. The correlation between the test results and the reactor dynamic safety characteristics (stability, self-shutdown under excursion conditions, etc.) is investigated. (T.F.H.)
Date: July 20, 1961
Creator: Forbes, S. G. & Nyer, W. E.
Partner: UNT Libraries Government Documents Department

ELECTROLYTIC DISSOLUTION OF NUCLEAR FUELS. PART I. ZIRCONIUM IN HCl- METHANOL

Description: The electrolytic dissolution of zirconium in HCl-methanol was studied as a function of potential, solution composition, and temperature. The dissolution is characterized by two regions. At high potentials the zirconium is electropolished and complete dissolution is achieved. At low potentials the current is an exponential function of the potential (Tafel behavior). In this region a small amount of finely divided alpha -zirconium which is insoluble in HCl-methanol separates from the bulk metal. The energy of activation for the corrosion reaction (0.0 volt) is 16.5 kcal/mole; in the electropolishing region (1.0 volt) the activation energy is 7.7 kcal/mole. A broad solvent capability for metallic reactor fuels is offered by the HCl-methanol medium since, in addition to zirconium, stainless steel is also dissolved electrolytically while uranium and aluminum dissolve chemically. Other process implications are discussed. (auth)
Date: December 29, 1961
Creator: Aylward, J. R.; Whitener, E. M. & Hahn, H. T.
Partner: UNT Libraries Government Documents Department

ELECTROLYTIC DISSOLUTION OF NUCLEAR FUELS. PART III. STAINLESS STEEL (304) IN NITRATE SOLUTIONS

Description: The potential-current density relationships for 304 stainless steel dissolution in a nitrate system were studied as a function of solution composition and temperature in order to optimize the conditions for electrolytic dissolution of ihis material. In the nitrate system, the anodic dissolution of steel takes place in the transpassive region. Under some conditions, deviations from Tafel behavior are observed which depend greatly on the nitrate and hydrogen ion concentration, and on temperature. A discussion of passivity, transpassivity, secondary passivation, the limiting current density, and the effect of alloy composition on the dissolution behavior is given. It was found that at temperatures above 60 deg C efficient dissolver operation should be possible over a wide range of solution compositions and at current densities up to 2 amp/cm/sup 2/. (auth)
Date: June 1, 1962
Creator: Aylward, J. R. & Whitener, E. M.
Partner: UNT Libraries Government Documents Department

Electrolytic Oxidation of Zirconium in Nitrate Solutions

Description: Zirconiurn alloys used in the fabrication of nuclear fuel elements can be disintegrated and converted to insoluble oxides by electrolytic treatment in concentrated nitrate solutions. This reaction shows promise as a technique for reprocessing nuclear fuels clad with Zircaloy-2. For a particular applied voltage, nitric acid achieves the highest rate of attack, but the reaction can be carried out at rates of 2 mg/(cm/sup 2/)(min) or greater in either 7.5M sodium nitrate or 2.3M aluminum nitrate. A reaction rate of 7 mg/(cm/sup 2/) (min) can be easily attained in either 8M nitric acid or 7.5M sodium nitrate. The rate of reaction is a function of the temperature and tho applied voltage. An as-yet unsolved problem is the carry--down of uranium with the insoluble zirconium oxide product. (auth)
Date: December 29, 1961
Creator: Bomar, M. R.
Partner: UNT Libraries Government Documents Department

Eocr Control Rod Latch Reliability Test

Description: The final Vard design latch mechanism and hook for the EOCR Control Rod Drive Assembly was successfully and reliably operated in a hot organic medium containing particulates one hundred times the anticipated concentration in the EOCR and with a simulated heavy polymer deposition on all primary latch components. (auth)
Date: March 1, 1962
Creator: Burroughs, E. & Cohen, S.
Partner: UNT Libraries Government Documents Department