Material property correlations for uranium mononitride: IV. Thermodynamic properties

Abstract The experimental data for the specific heat (CP), enthalpy (H), entropy (S), Gibbs free energy (G) and the free energy function (FEF), nitrogen and uranium vapor pressures (PN2,U), and melting point (Tm) of uranium mononitride (UN) have been collected and reviewed. Empirical correlations for these properties as functions of temperature (T, in K) or nitrogen pressure (Pn2, in atm) were developed and are given as: C p ( J/mol K )=51.14(Θ/T) exp (Θ/T) [ exp (Θ/T)−1] 2 +9.491×10 −3 (T)+ 2.642×10 11 T 2 exp {−18081/T} , H(T)−H(298 K)( J/mol )= 51.14Θ exp (Θ/T)−1 +4.746×10 −3 (T) 2 −8148.34+1.461×10 7 exp {−18081/T} , S( J/mol K )= 51.14(Θ/T) exp (Θ/T)−1 −51.14 ln {1− exp (−Theta;/T)}+9.491×10 −3 (T)+16.31, G( J/mol ) = 51.14(T) ln {1− exp ( −Θ T )} −4.746×10 −3 (T) 2 −16.31 + 1.461 × 10 7 exp { −18081 T } , FEF(J/mol K) = −51.14 ln {1− exp (−Θ/T)}+4.746×10 −3 (T)+ 8148.34 T +16.31− 1.461×10 7 T exp {−18081/T} , log 10 (P N 2 , atm) = 1.822 + 1.882×10 −3 (T)−23543.4/T , log 10 (P U , atm) = 6.965 − 5.137×10 −4 (T)−26616.1/T T m (K) = 3035.0(P N 2 ) 0.02832 , where Θ is the empirically determined Einstein temperature of UN, 365.7 K. The specific heat correlation was constructed from experimental data in the range of 298 ≤T ≤ 2628 K. The enthalpy, entropy, Gibbs free energy and free energy function correlations were derived from the specific heat correlation and are therefore only strictly applicable over the same temperature range. The nitrogen and uranium vapor pressure correlations are valid for 1400 ≤ T ≤ 3107 K and 1400 ≤ T ≤ 2400 K, respectively, and the melting point correlation is valid for 10−13 ≤ PN2 ≤ 7.5 atm. However, all of the correlation forms employed are very stable; thus, application of these correlations to temperatures above the experimental limits should yield reasonable estimates for these properties.

[1]  J. Navratil,et al.  The chemical thermodynamic properties of nuclear materials. (II) High temperature enthalpy of the uranium carbides , 1973 .

[2]  J. B. Conway,et al.  PHYSICAL AND MECHANICAL PROPERTIES OF REACTOR MATERIALS. , 1969 .

[3]  W. M. Olson,et al.  THE DECOMPOSITION PRESSURE AND MELTING POINT OF URANIUM MONONITRIDE1 , 1963 .

[4]  Tagawa Hiroaki.  Phase relations and thermodynamic properties of the uranium-nitrogen system , 1974 .

[5]  D. L. Keller,et al.  FABRICATION AND PROPERTIES OF HOT-PRESSED URANIUM MONONITRIDE , 1963 .

[6]  Jerry F. Kerrisk,et al.  Smoothed Values of the Enthalpy and Heat Capacity of UO2 , 1972 .

[7]  M. Murabayashi,et al.  Uranium mononitride: Heat capacity and thermal conductivity from 298 to 1000 °K , 1971 .

[8]  J. M. Leitnaker,et al.  Equilibrium Nitrogen Pressures and Thermodynamic Properties of UN , 1968 .

[9]  Gregory R. Choppin,et al.  The Chemical Thermodynamics of Actinide Elements and Compounds , 1979 .

[10]  Hj. Matzke,et al.  Science of advanced LMFBR fuels , 1986 .

[11]  E. Cordfunke,et al.  The heat capacity of uranium mononitride , 1972 .

[12]  H. Inaba,et al.  Heat capacity measurement of U1−yGdyO2 (0.00 ≦ y ≦ 0.142) from 310 to 1500 K , 1987 .

[13]  J. M. Leitnaker,et al.  CHEMICAL THERMODYNAMIC PROPERTIES OF NUCLEAR MATERIALS. I. URANIUM MONONITRIDE. , 1972 .

[14]  J. C. Slater.  Introduction to chemical physics , 1933 .

[15]  Christian Affortit.  Chaleur specifique de UC et UN , 1970 .

[16]  E. Cordfunke,et al.  Investigations on uranium carbonitrides: III. Nitrogen vapour pressures and thermodynamic properties , 1980 .

[17]  C. Catlow,et al.  The specific heat anomaly in crystalline UO2 , 1980 .

[18]  P. W. Winter.  The electronic transport properties of UO2 , 1989 .

[19]  S. Landsberger,et al.  Measurement and detection of radiation , 1983 .

[20]  P. W. Winter,et al.  A theoretical analysis of the electronic specific heat of solid urania , 1986 .

[21]  E. Westrum,et al.  Uranium Mononitride: Heat Capacity and Thermodynamic Properties from 5° to 350°K , 1966 .

[22]  A. A. Bauer,et al.  Phase Relations in the System Uranium—Nitrogen , 1964 .

[23]  R. L. Petty,et al.  Fabrication and testing of uranium nitride fuel for space power reactors , 1988 .

[24]  K. Gingerich.  Vaporization of Uranium Mononitride and Heat of Sublimation of Uranium , 1969 .

[25]  George Paul Sabol,et al.  A new strain gage method for measuring the contractile strain ratio of Zircaloy tubing , 1988 .

[26]  R. Dell,et al.  Thermodynamic properties of uranium compounds. Part 2.—Low-temperature heat capacity and entropy of three uranium nitrides , 1966 .