A relatively simple method is introduced for calculating two-phase equ
ilibria in ternary systems using a macro-driven spreadsheet . The meth
od is applied to the U-Zr-C ternary system. The thermodynamic algorith
m used in calculating phase boundaries is based on free energy minimiz
ation methods described by Chang and Rudy. However, the computational
technique described in this paper can easily be adapted to many other
thermodynamic models.