Abstracts and Available Papers Presented at the
2005 International RERTR Meeting

FIRST PRINCIPLES CALCULATIONS OF LATTICE PARAMETER AND ELASTIC CONSTANTS OF BCC γ(U,Mo) DISORDERED PHASE.

Pablo Gargano, Paula R. Alonso, Hugo O. Mosca, Juan C. Ríos and María Ortiz
Albuixech,
Departamento de Materiales – Centro Atómico Constituyentes – Comisión Nacional de Energía Atómica,
Avda Gral Paz 1499, San Martín, Buenos Aires, CP 1650, Argentina.
,

and

Gerardo H Rubiolo,
Departamento de Materiales – Centro Atómico Constituyentes – Comisión Nacional de Energía Atómica,
Avda Gral Paz 1499, San Martín, Buenos Aires, CP 1650, Argentina.
Consejo Nacional de Investigaciones Científicas y Tecnológicas, CONICET, Argentina.

ABSTRACT

IRRADIATION TESTS HAVE SHOWN THAT U-MO DISPERSION FUEL SUFFERS FROM INTERACTION BETWEEN THE FUEL AND THE ALUMINUM MATRIX AT HIGHER TEMPERATURE. A POTENTIAL SOLUTION TO MITIGATE THESE PHENOMENA IS TO USE A FUEL ALLOY FOIL IN PLACE OF THE FUELALUMINUM DISPERSION. THIS MONOLITHIC FUEL PROVIDES A LOWER FUELMATRIX INTERFACIAL SURFACE AREA AND A MUCH HIGHER URANIUM DENSITY THAN DISPERSION TYPE FUEL. INTERNAL STRESSES WILL ARISE, DURING FABRICATION AND OPERATING CONDITIONS, IN THE INTERFACE BETWEEN FUEL AND CLADDING MATERIALS DUE TO THE DIFFERENCE IN THERMAL EXPANSION COEFFICIENTS AND ELASTIC CONSTANTS. OUR AIM IS TO ASCERTAIN THESE PROPERTIES FOR THE GAMMA PHASE IN THE U-MO ALLOY FROM THE KNOWLEDGE OF ITS INTERNAL ENERGY AS A FUNCTION OF DEFORMATION. INTERNAL ENERGY OF THE DISORDERED PHASE IS OBTAINED AS A CLUSTER EXPANSION FROM AB INITIO CALCULATED INTERACTION PARAMETERS IN EACH OF THREE DEFORMATION MODES: HYDROSTATIC, TETRAGONAL AND TRIGONAL. PRELIMINARY RESULTS ARE PRESENTED THAT HAVE SERVED AS A PROOF OF METHOD SUITABILITY.

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