401 Matching Results

Search Results

Advanced search parameters have been applied.

PROGRESS RELATING TO CIVILIAN APPLICATIONS DURING DECEMBER 1959

Description: >The creep and stress-rupture propenties of annealed and of 15% cold- worked Zircaloy-2 are being determined at of a AgBr fuel-element leak detector for use in watercooled reactors. The development of a thermal-neutronflux monitoring system was directed toward extending the sensing-probe life, increasing the effective instrument range, and improving the instrument reliability. Resistivity of Al/sub 2/O/sub 3/-MoSi/sub 2/-UO/sub 2/ ceramic tubes was determined to investigate the effects of MoSi/sub 2/ propontion and of extrusion pressure. In the development of corrosion-resistant welding alloys for use with Hastelloy F, a number of alloys are being exposed in boiling Sulfex and Niflex solutions to determine corrosion resistance of these liquids. Corrosion tests in 200-C water for 30 days have shown that the Al--35 wt.% U alloys containing Sn or Zr additives are equivalent to the binary Al--35 wt.% U and superior to 2S Al in their resistance to the corrosion attack of 200 deg C water. Work was continued on the development of a radiometric titration method of determining Al and Fe in portland cement. The investigation of the formation and decay of radiation-induced free radicals was continued. The effect of radiation on the nitration of cyclohexane was stadied over the range of 15 to 70 wt.% HNO/ sub 3/ with a 10-to-1 ratio of organic to acid. An investlgation is being conducted on the effects of combined high pressure and temperature on the uranium oxides and on the reactions of uranium oxides with other oxide systems. An irradiation surveillance program on AISI Type 347 stainless steel is continuing. The alloys which are being investigated as alternate cladding materials for the EBR include Nb, Nb-1.84 wt.% Cr, Hb--3.21 wt.% Cr, Nb--4.33 wt.% Zr. Nb--9.95 wt.% Ta--3.31 wt.% Cr, Nb--39.8 wt.% Ti--10.6 wt.% Al, Nb--20.5 wt.% Ti--4.28 wt.% Cr, and V--11.7 wt.% Ti--3.07 wt.% ...
Date: January 1, 1960
Creator: Dayton, R.W. & Tipton, C.R. Jr.
Partner: UNT Libraries Government Documents Department

METALLOGRAPHY OF PYROLYTIC CARBON COATED AND UNCOATED URANIUM CARBIDE SPHERES

Description: Metallographic techniques are described which were developed for examining coated and uncoated uranium carbid particles, both in the unsupported condition and in graphite matrices. The structural and compositional variations in various batches and within a given batch are presented, and the effects of various heat treatments on the particles and the coatings are described. (D.L.C.)
Date: March 21, 1962
Creator: DuBose, C.K.H. & Gray, R.J.
Partner: UNT Libraries Government Documents Department

A STUDY OF THE EFFECTS OF FABRICATING CONDITIONS ON SOME PROPERTIES OF SINTERED URANIUM MONOCARBIDE

Description: The effect of initial particle size (6.2 and 14.7 mu ), forming pressure (50,000 and 100,000 psi), temperature (1600 and 1800 deg C), and time at temperature (1 and 3 hr) on the bulk density, grain size, and porosity of sintered uranium monocarbide compacts was studied, Within the limits of the variables studied there appeared to be no significant changes in these properties of the sintered material attributable to the changes in the fabricating conditions. (auth)
Date: October 1, 1959
Creator: Tripler, A.B. Jr.; Snyder, M.J. & Duckworth, W.H.
Partner: UNT Libraries Government Documents Department

Zone sintering of ceramic fuels

Description: Cold pressed UC{sup 2} fuel compacts are sintered at temperatures greater than about 1850 C while in contract with a sintering facilitator material, e.g., tantalum, niobium, tungsten or a metal carbide such as uranium carbide, thereby allowing for a reduction in the overall porosity and leaving the desired product, i.e., a highly dense, large-grained uranium dicarbide. The process of using the sintering facilitator materials can be applied in the preparation of other carbide materials.
Date: December 31, 1991
Creator: Matthews, R.B.; Chidester, K.M. & Moore, H.G.
Partner: UNT Libraries Government Documents Department

A thermokinetic model describing the vaporization behavior of U{sub x}Zr{sub 1-x}C{sub 1-y} in hydrogen

Description: This paper describes the thermodynamics and kinetics of the corrosion of U{sub x}Zr{sub 1-x}C{sub 1-y} in hydrogen gas. It describes how corrosion rates are influenced by variables such as pressure, temperature, and gas flow rate. A model is developed which agrees with experimental steady-state corrosion rates at 1 atm between 2670 and 3100 K. It is shown that under steady-state conditions the corrosion flux is rate limited by the vapor phase transport of Zr(g) away from the solid surface to the bulk gas stream where the partial pressure of Zr(g) is determined by the congruently vaporizing surface composition. Extrapolation of the model to higher pressures indicates that Zr(g) transport should also be rate limiting at higher pressures but the corrosion rate should decrease slightly with increased hydrogen pressure due to reduced gaseous diffusion rates. The model predicts that the corrosion rate will increase as the square root of gas velocity for a given temperature and pressure. Calculations demonstrating the effects of gas velocity are in agreement with experimental studies.
Date: May 1, 1993
Creator: Butt, D. P
Partner: UNT Libraries Government Documents Department

Planning for Uranium Carbide Transient Heating Experiments in Treat

Description: The initial experimental program to study the transient heating of uranium carbide fuel in TREAT is outlined. Preliminary analyses are presented for the behavior of an HNPF prototype UC fuel slug during power bursts in the TREAT reactor. The analysis and evaluation conducted, center around the proposed utilization of the existing GE capsule, and indicate that this equipment will be suitable for the initial uranium carbide experiments with minor modification. A survey is presented and found not to be significantly different from the GE-UO/ sub 2/ experiments. A planning schedule for the program is shown, and in addition, recommendations for additional studies which should be conducted are presented. (auth)
Date: October 17, 1962
Creator: Silberberg, M. & Spiegler, P.
Partner: UNT Libraries Government Documents Department

CONSTITUTION OF LOW CARBON U-C ALLOYS

Description: (((Abstract unscannable)))<><DSN>13:014503<ABS>Thc Nb-O equilibrium system was determined by metallographic examination of arc-cast alloys made ot electron-gun-refined Nb metal and special purity Nb/sub 2/O/sub 5/. Two intermediate oxides. NbO and NbO/sub 2/, melt without decomposition at 1945 C and 1915 C, respectively. Eutectic reactions exist between Nb and NbO at 1915 C and between NbO and NbO/sub 2/ at 1810 C . Experimental evidence supports a peritectic reaction between NbO/sub 2/ and Nb/sub 2/O/sub 5/ at 1510 C. The maxinium solid solubility of 0 in Nb metal is 0.72 wt.%. (auth)
Date: February 1, 1959
Creator: Blumenthal, B.
Partner: UNT Libraries Government Documents Department

RECOVERY OF U FROM PYROLYTIC CARBON-COATED UC$sub 2$ SPHEROIDS

Description: 100% recovery of uranium from pyrolytic carboncoated spheroids of uranium dicarbide was accomplished by an aqueous electrolytic process at the small scale laboratory level. This result was obtained in a system which circulated 1 molar nitric acid through a thin bed of the spheres. The bed was supported between a glass frit and the anode, with which the bed was in contact. The anode was a spiral of platinum wire; the cathode was a grid of tantalum wire. Current density was about 0.2 the average particle size of 150 microns. Initial flow rate was about 1.3 ml/cm/sup 2//sec. Reaction temperature was 72 to 82 deg C; time was 15 hours. At 1/5 the above current density and at the same teraperature, recovery was smaller and was independent of concentration of nitric acid over the range 1 to 4 molar; also recovery in 1 molar dramonium nitrate was about the sarie as in 1 molar HNO/sub 3/. About a 100-fold increase in recovery was obtained by going from a convection stirred cell at 90 deg C to the pumped type of cell at 54 deg C using ammonium nitrate as the electrolyte. (auth)
Date: January 1, 1962
Creator: Katz, H. & Wagner, J.
Partner: UNT Libraries Government Documents Department

Processing of Uranium Carbide Reactor Fuels. I. Reaction With Water and HCl

Description: High-purity uranium monocarbide reacted with water at 80 deg C to produce a finely divided, brown U(IV) compound, and 92 nfl (STP) of gas per gram consisting of 11 vol% hydrogen, 86 vol% methane, 2 vol% ethame, and 0.6 vol% propane. At 90 deg C, the products were the same, but the reaction rate was higher. Reaction with 5.6 M HCl was slower than with water, but the gaseous products were essentially the same. In preliminary experiments at 80 deg C with UC-UC/sub 2/ mixtures containing less than 2 wt.% free carbon, the volume of gas evolved per gram of sample hydrolyzed decreased from 92 to 32 ml (STP) and the methane concentration from 86 to 14 vol% as the UC/sub 2/ concentration in the mixture increased from 0 to about 63 wt.%. An attendant increase in the hydrogen and ethane concentrations to 23 and 38 vol%, respectively, also occurred. (anth)
Date: August 15, 1961
Creator: Bradley, M. J. & Ferris, L. M.
Partner: UNT Libraries Government Documents Department

Synthesis and Fabrication of Refractory Uranium Compounds. First Quarterly Report, March 1 Through May 31, 1961

Description: Activities in a program to obtain UC pellets of maximum density for irradiation testing are described. A study was made of the effects of the UC powder thermal history, sintering time, sintering temperature, and additives on the UC sinterability. Preliminary results indicate that the UC powder synthesized under the most severe conditions of temperature and time (1740 deg C, 107 min) was less sinterable than powders prepared at lower temperatures, or at the same temperature for shorter time. It was also concluded that although both temperature and time of sintering pellets affect density, temperature is more important. Additions of Fe (0.1 to 1.0%) improve sinterability and promote grain growth. The final density obtained on sintering in a vacuum was about the same as that resulting from sintering in He at atmospheric pressure. (J.R.D.)
Date: June 29, 1961
Creator: Taylor, K. M. & McMurtry, C. H.
Partner: UNT Libraries Government Documents Department

THE MUTUAL SOLID SOLUBILITY OF HAFNIUM CARBIDE AND URANIUM MONOCARBIDE

Description: In contrast to the miscibility gap previously reported for the system HfC-UC, complete solid solubility of these carbides at 2000 c- C was demonstrated. Included are the preparation, heating conditions, x-ray data, and chemical analysis of the starting materials and the solid solutions. (P.C.H.)
Date: June 1, 1963
Creator: Krikorian, N.H.; Witteman, W.G. & Bowman, M.G.
Partner: UNT Libraries Government Documents Department