Authors & Affiliations
Krasin V.P., Soyustova S.I.
Federal State Educational Institution of Higher Professional Education "Moscow State Industrial University", Moscow, Russia
The use of liquid low melting point metals as coolants for nuclear reactors, particularly sodium, has led to a growing interest in the solution chemistry of these liquids to further the understanding of many of corrosion problems encountered in their use. A detailed knowledge of the thermochemical data on Na-O-H system is needed for utilization of steam/water leak detecting systems since they function by measuring the hydrogen activity in sodium and this is influenced by the oxygen which is also introduced during these leaks. A procedure for calculating the thermodynamic activity coefficients of oxygen and hydrogen in dilute Na–O–H system melts in the temperature range 300–600°C was suggested. The thermodynamic activity coefficients of hydrogen in liquid sodium calculated by the coordination-cluster model equations were used to determine the equilibrium hydrogen pressure over melts. The equations of the coordination cluster model are useful to provide understanding of a relationship between thermodynamic properties and local ordering in the melt. The model allows to estimate the fraction of oxygen atoms in the configuration of definite type and, thus enables to make the conclusion about cluster composition of the melt. The calculation results were compared with theexperimental partial hydrogen pressures over the Na(excess) - Na2O-NaH system at XO=XH. The calculated valueswere in qualitative agreement with the experimental data.
thermodynamic properties, the concentration of clusters, the first coordination sphere, the equilibrium pressure, the constant of the reaction, the energy parameter, interstitial position, metal solvent, thermodynamic activity, Sievert’s constant
1. Oberlin C., Saint-Paul P. Thermodynamic and experimental study of sodium hydroxide decomposition in sodium between 430 and 550°. Material Behavior and Physical Chemistry in Liquid Metal Systems. Edited by H.U. Borgstedt. N.Y.: Plenum Press. 1982, pp.275-285.
2. Smith C.A., Whittingham A.C. Thermodynamic and kinetic aspects of oxygen-hydrogen interaction in liquid sodium. Material behavior and physical chemistry in liquid metal systems.Edited by H.U. Borgstedt. N.Y.: Plenum Press, 1982, pp.365-374.
3. Ullman H. The reactions of oxygen and hydrogen with liquid sodium - a critical survey. Material behavior and physical chemistry in liquid metal systems. Edited by H.U. Borgstedt. N.Y.: Plenum Press, 1982, pp.375-386.
4. Knights C.F., Whittingham A.C. The equilibrium hydrogen pressure-temperature diagram for the liquid sodium-hydrogen-oxygen system. Material behavior and physical chemistry in liquid metal systems. Edited by H.U. Borgstedt. N.Y.: Plenum Press, 1982, pp.287-296.
5. Ljupis K. Himicheskaja termodinamika materialov. M.: Metallurgija. 1989, 503 p. [in Russian]
6. Ostrovskij O.I., Grigorjan V.A., Vishkarev A.F. Svojstva metallicheskih rasplavov. M.: Metallurgija. 1988, 304 p. [in Russian]
7. Ohtani H., Nishizava T. Calculation of Fe-C-S ternary phase diagram. Transactions ISIJ. 1986, v. 26, pp. 655-663.
8. Saboungi M.-L., Caveny D., Bloom I., Blander M. The Coordination Cluster Theory: Extension to Multicomponent Systems. Metallurgical Transactions A. 1987, v. 18A, pp. 1779-1783.
9. Saboungi M.-L., Cerisier P., Blander M. The coordination cluster theory - description of the activity coefficients of dilute solutions of oxygen and sulfur in binary alloys. Metallurgical Transactions B. 1982, v. 13, pp. 429-437.
10. Chan Y.C., Veleckis E. Thermodynamic investigation of dilute solutions of hydrogen in liquid Li-Pb alloys. Journal of Nuclear Materials. 1984, v. 122-123, pp. 935.
11. Krasin V.P., Soyustova S.I. Comparison of liquid metal solution model predictions with compatibility data of niobium with liquid sodium. Journal of Nuclear Materials. 2014, v. 451, pp. 24-27.
12. Kubashevskij O., Olkokk K.B. Metallurgicheskaja termohimija. Perevod s angl. M.: Metallurgija. 1982, 393 p.
13. Rumbaut N., Casteels F., Brabers M. Thermodynamic potential of nitrogen, carbon, oxygen and hydrogen in liquid lithium and sodium. Material behavior and physical chemistry in liquid metal systems. Edited by H.U. Borgstedt. N.Y.: Plenum Press, 1982, pp. 437.
14. Prigozhin I., Kondepudi D. Sovremennaja termodinamika. Ot teplovyh dvigatelej do dissipativnyh struktur: Per. s angl. M. Mir. 2002, 461 p.