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SYNTHESIS AND FABRICATION OF REFRACTORY URANIUM COMPOUNDS. Monthly Progress Report No. 10 for September 1 through September 30. 1960

Description: Several synthesis experiments were carried out to provide a stock of U/ sub 3/Si/sub 2/, powders for fabrication of test specimens. Initial thermal- expansion characteristics were determined on U/sub 3/Si/sub 2/ bars. High densities were obtained in the preparation of UN bodies. Thermal-expansion tests were made on bars of UN with a high-density silicon carbide tube dilatometer in a flowing argon atmosphere. (W.L.H.)
Date: October 13, 1960
Creator: Taylor, K.M. & McMurtry, C.H.
Partner: UNT Libraries Government Documents Department

SYNTHESIS AND FABRICATION OF REFRACTORY URANIUM COMPOUNDS. Summary Report for May 1959 through December 1960

Description: Activitiee are described in an investigation to develop refractory U materiala for superior reactor fuels. Uranium carbide was prepared by cold pressing in pellets with densitier of 92 to 96% of theoretical. Uranium nitride was synthesized, and it was found that dense specimens (95% of theoretical) could be obtained in N-deficient powder, however in stochiometric compositions the maximum density obtained was 85% of theoretical. In other work dense uranium silicide was prepared and several properties of UC, UN, and U/sub 3/Si/sub 2/ were studied. (J.R.D.)
Date: February 1, 1961
Creator: Taylor, K.M. & McMurtry, C.H.
Partner: UNT Libraries Government Documents Department

SYNTHESIS AND FABRICATION OF REFRACTORY URANIUM COMPOUNDS. Quarterly Report No. 5, August 1 through October 31, 1960

Description: Additional quantities of UC, UN, and U/sub 3/Si/sup 2/ were prepared to be used in fabrication of test specimens for property determinations. A reduction in oxygen contamination of UN and U/sub 3/Si/sup 2/as achieved by improved techniques of synthesis.>s Preliminary values for thermal expansion, modulus of elasticity, and corrosion in boiling water were also obtained for these materials. (For preceding period see TID-6591.) (J.R.D.)
Date: November 15, 1960
Creator: Taylor, K.M. & McMurtry, C.H.
Partner: UNT Libraries Government Documents Department

Thermodynamic Factors Affecting UC<sub>1-x</sub>N<sub>x</sub>Irradiation and Synthesis

Description: There is interest in attempting to synthesize nearly pure uranium nitride (UN) kernels for high-temperature gas-cooled reactor (HTGR) fuel. Because the proposed process involves carbothermic conversion of a urania-carbon mixture in nitrogen and because there is a complete ideal solution of uranium carbide (UC) and UN, which is written as UC{sub 1-x}N{sub x}, the practical value of x for fuel irradiation needs to be determined. Insight is to be gained by relevant thermodynamic calculations of carbide-nitride equilibria for the fuel and fission product systems. The equilibria are readily compared on the nitrogen-based Ellingham diagram, which, in turn, provides guidance in interpreting past irradiations and in synthesis of the UC{sub 1-x}N{sub x} kernels.
Date: April 22, 2005
Creator: Lindemer, T.B.
Partner: UNT Libraries Government Documents Department

THE URANIUM-NITROGEN-CARBON SYSTEM

Description: The ternary system uranium- nitrogen- carbon has been studied at 1800 deg C under vacuum and under a 1atm. nitrogen pressure. There is complete solid solubility between UN and UC, and essentially no solid solubility of nitrogen in UC/sub 2/ or U/sub 2/C/sub 3/ or of carbon in U/sub 2/N/su b 3/. At 1800 deg C the two-phase field, U(C,N) and UC/sub 2/, and the three-phase field, U(C,N), UC/ sub 2/, and C, exist in vacuum or argon. At 1 atm. of nitrogen, the uranium nitrides are more stable than the uranium carbides up to 1800 deg C, but at 2000 deg C, the uranium carbides UC/sub 2/ + U(C,N) become more stable. At 1 atm. of nitrogen, U/sub 2/N/sub 3/ is the stable phase up to 1550 deg C, and U(N,C) solid solution is stable at 1800 deg C. (auth)
Date: June 23, 1958
Creator: Austin, A.E. & Gerds, A.F.
Partner: UNT Libraries Government Documents Department

Experience related to the safety of advanced LMFBR fuel elements

Description: Experiments and experience relative to the safety of advanced fuel elements for the liquid metal fast breeder reactor are reviewed. The design and operating parameters and some of the unique features of advanced fuel elements are discussed breifly. Transient and steady state overpower operation and loss of sodium bond tests and experience are discussed in detail. Areas where information is lacking are also mentioned. (auth)
Date: July 1, 1975
Creator: Kerrisk, J.F.
Partner: UNT Libraries Government Documents Department

Oxidation Protection of Uranium Nitride Fuel using Liquid Phase Sintering

Description: Two methods are proposed to increase the oxidation resistance of uranium nitride (UN) nuclear fuel. These paths are: (1) Addition of USi{sub x} (e.g. U3Si2) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with various compounds (followed by densification via Spark Plasma Sintering or Liquid Phase Sintering) that will greatly increase oxidation resistance. The advantages (high thermal conductivity, very high melting point, and high density) of nitride fuel have long been recognized. The sodium cooled BR-10 reactor in Russia operated for 18 years on uranium nitride fuel (UN was used as the driver fuel for two core loads). However, the potential advantages (large power up-grade, increased cycle lengths, possible high burn-ups) as a Light Water Reactor (LWR) fuel are offset by uranium nitride's extremely low oxidation resistance (UN powders oxidize in air and UN pellets decompose in hot water). Innovative research is proposed to solve this problem and thereby provide an accident tolerant LWR fuel that would resist water leaks and high temperature steam oxidation/spalling during an accident. It is proposed that we investigate two methods to increase the oxidation resistance of UN: (1) Addition of USi{sub x} (e.g. U{sub 3}Si{sub 2}) to UN nitride powder, followed by liquid phase sintering, and (2) 'alloying' UN nitride with compounds (followed by densification via Spark Plasma Sintering) that will greatly increase oxidation resistance.
Date: March 1, 2012
Creator: Lessing, Dr. Paul A.
Partner: UNT Libraries Government Documents Department

SYNTHESIS AND FABRICATION OF REFRACTORY URANIUM COMPOUNDS. Monthly Progress Report No. 11, November 1-November 30, 1960

Description: Batches of UC were synthesized for use in fabrication of specimens for physical property determinations. This synthesis was carried out with mixed loose powders in a graphite crucible. Two and one-half pound batches of UN were synthesized using a stainless steel boat and an Inconel muffle furnace. Three batches of U/sub 3/Si/sub 2/ were synthesized with particular emphasis on controlling the rate of the reaction by limiting the maximum temperature to 1500 deg C. In addition, determinations were made of modulus of rupture, shear modulus, and Poisson's ratio of sintered UC, UN, and U/sub 3/Si/sub 2/ specimens. (M.C.G.)
Date: December 13, 1960
Creator: Taylor, K.M. & McMurtry, C.H.
Partner: UNT Libraries Government Documents Department