PROCEEDINGS OF A SYMPOSIUM, VIENNA, 22 — 27 JULY 1965 ORGANIZED Ф BY THE IAEA IN CO-OPERATION W I TH THE IUPAC THERMODYNAMICS INTERNATIONAL ATOMIC ENERGY AGENCY, VIENNA.1966 THE RMOD YNAM ICS Vol.1 PROCEEDINGS SERIES THERMODYNAMICS PROCEEDINGS OF THE SYMPOSIUM ON THERMODYNAMICS WITH EMPHASIS ON NUCLEAR MATERIALS AND ATOMIC TRANSPORT IN SOLIDS ORGANIZED BY THE INTERNATIONAL ATOMIC ENERGY AGENCY IN CO-OPERATION WITH THE COMMISSION ON THERMODYNAMICS AND THERMOCHEMISTRY OF THE INTERNATIONAL UNION OF PURE AND APPLIED CHEMISTRY AND HELD IN VIENNA, 22-27 JULY 1965 VOL.1 In two volumes INTERNATIONAL ATOMIC ENERGY AGENCY VIENNA, 1966 Symposium on Thermodynamics with Emphasis on Nuclear Materials and Atomic Transport in Solids, Vienna, 22 -27 July, 1965. Proceedings ... organized by the International Atomic Energy Agency in co-operation with the Commission on Thermodynamics and Thermo- chemistry of the International Union of Pure and Applied Chemistry . . . Vienna, the Agency, 1966. 2 vols. (IAEA, Proceedings series) 541.11 621.039.517 536.7 THERMODYNAMICS, IAEA, VIENNA, 1966 STI/PUB/109 Printed by the IAEA in Austria January 1966 FOREWORD Knowledge of the thermodynamics of nuclear materials is vital to the design of reactor fuels and moderating and cooling systems, in fact all facets of nuclear plant operation that involve mixtures of, or contact between, two or more elements in single- or multi-phase systems. The steep thermal gradients and the high temperatures involved in nuclear technology pose special problems for engineers and thermodynamicists, who have found that extrapolation of low-temperature data to high temperatures very often proves invalid. For this reason, standard thermodynamic techniques such as calorimetry and EMF-methods have been extended into high-temperature regions. Since the Agency's last conference on this subject, also held in Vienna (Thermodynamics of Nuclear Materials, 1962), there have been notable ad- vances in calorimetry performed at temperatures greater than 1000°C, and in the use of EMF cells with solid electrolytes operated at similar tempera- tures. Significant advances have also been made in measuring diffusion parameters at the higher temperatures. An important field covered in this Symposium was the correlation of such atomic transport data with thermodynamic data, a prerequisite if the nuclear engineer is to incorporate diffusion results into his normal process- assessment techniques. Finally the Symposium suggested the requirements for good critical tables. The mere compiling of such data is no longer sufficient; the com- piler must have free access to all the data of a particular experiment, he must have an intimate knowledge of experimental work in this field and he must weight every figure quoted in the light of his experience. As a step in this direction, the Agency has called on the services of many well-known experts and is preparing a number of monographs giving critical assess- ments of thermodynamic data and phase-diagrams for many of the elements of interest in reactor design. Most of the countries engaged in research in thermodynamics were represented at the meeting, which was held in co-operation with the Commission on Thermodynamics and Thermochemistry of the International Union of Pure and Applied Chemistry. EDITORIAL NOTE The papers and discussions incorporated in the proceedings published by the International Atomic Energy Agency are edited by the Agency's edi- torial staff to the extent considered necessary for the reader's assistance. The views expressed and the general style adopted remain, however, the responsibility of the named authors or participants. For the sake of speed of publication the present Proceedings have been printed by composition typing and photo-offset lithography. Within the limi- tations imposed by this method, every effort has been made to maintain a high editorial standard; in particular, the units and symbols employed are to the fullest practicable extent those standardized or recommended by the competent international scientific bodies. The affiliations of authors are those given at the time of nomination. The use in these Proceedings of particular designations of countries or territories does not imply any judgement by the Agency as to the legal status of such countries or territories, of their authorities and institutions or of the delimitation of their boundaries. The mention of specific companies or of their products or brand-names does not imply any endorsement or recommendation on the part of the Inter- national Atomic Energy Agency. CONTENTS OF VOLЛ INTRODUCTORY LECTURE Thermochemistry and.nuclear engineering (SM-66/29) 3 M.H. Rand and L.E.J. Roberts CALORIMETRY AT HIGH TEMPERATURES (Session 1) Calorimetry at high temperatures (SM-66/93) 35 F. Grtfnvold A high température isothermal calorimeter (SM-66/90) 53 J.R. Lacher, H. Gottlieb, P. Fowell andJ.D. Park Les chaleurs de mélange dans les systèmes binaires de sels fondus (SM-66/20) . . 67 I. G. Murgulescu et D. I. Marchidan Emploi d'un calorimètre sous vide pour la mesure des chaleurs de dissolution de Ge, Al et Ag dans Sn à 700°C; mesures des enthalpies de Sn, ZrB2, BN et TÍB2, B4C (SM-66/55) 75 J. -C. Mathieu, F. Durand et E. Bonnier Discussion to Session 1: Calorimetry at high temperatures 89 EMF METHODS, INCLUDING SOLID ELECTROLYTES (Session 2) The EMF method in studying thermodynamic and kinetic properties of compounds at elevated temperatures (SM-66/,98) . . . . 97 i: H. Schmalzried The application of oxygen concentration cells with the solid electrolyte Zr02- CaO to thermodynamic research (SM-66/15) .. . Ill Y. Matsushita and K. Goto Measurements of the thermodynamic stabilities of thé niobium and tantalum oxides using a high-temperature galvanic cell (SM-66/66) . 131 W.L. Worrell Thermodynamic data for plutonium oxides (SM-66/32)- ¡ 145 •T.L. Markin and M.H. Rand Solid-state EMF techniques: the free energies of formation of NiCl, and several double salts of KCl (SM-66/62) 157 2 C0CI2 J. J. Egan ! The free energies of formation of thorium borides from. . measurements on solid EMF. cells (SM-66/61) - 165 S. Aronson and A. Auskern Термодинамические свойства сплавов железа с кремнием (SM-66/38) . 171 P. A. Вечер, В. А. Гейдерих и Я .И. Герасимов Discussion to Session 2: EMF methods, including solid electrolytes . 181 VAPORIZATION (Session 3) Thermodynamics of vaporization of nuclear materials at high temperatures (SM-66/72) 191 P. W. Gilles Knudsen effusion studies of compounds of uranium and thorium with elements of Groups Illb anb IVb (SM-66/35) 211 С. B. Alcock, J. B. Cornish and P. Grieveson The vapour pressure of plutonium (SM-66/75) 231 R.N.R. Mulford The evaporation behaviour, thermodynamic properties and systematic trends of actinide metal-oxygen systems (SM-66/80) 243 R.J. Ackermann and R.J. Thorn Vaporization in the lithium fluoride-beryllium fluoride system (SM-66/26) ' 271 A. Büchler and J. L. Stauf fer The preparation and thermodynamics of europium dicarbide (SM-66/58) ;.. 291 R.E. Gebelt and H.A. Eick A mass spectrometric study of the vapour pressure of U(g) and UC(g) over various compositions in the uranium-carbon 2 system (SM-66/70) 309 E;K. Storms Les préssions de vapeur et l'association moléculaire des vapeurs du chlorure et du bromure de potassium fondus (SM-66/19) 345 I. G. Murgulescu et Letitia Marta Изучение упругости пара монокарбида урана (SM-66/107) 359 B. В. Хромоножкин и Р. А .Андриевский Discussion to Session 3: Vaporization 367 THERMODYNAMICS OF THE LIQUID STATE (Session IV) Thermodynamics of fused salts and fused salt mixtures (SM-66/89) .. 383 O. J. Kleppa The chemistry and thermodynamics of molten-salt-reactor fluoride solutions (SM-66/60) ; 409 C.F. Baes, Jr. Cation-exchange equilibria with fused salts (SM-66/86) 435 E. С. Freiling Practical application of thermodynamics to plutonium process reactions at high temperature (SM-66/69) 459 J.A. Leary and L. J. Mullins Densities of some low melting plutonium alloys (SM-66/73) 473 R.H. Perkins, L.A. Geoffrion and J. С. Biery