On the basis of morphological thermodynamics we develop an exactly solvable version of statistical mutifragmentation
model for the nuclear liquid-gas phase transition. It is shown that the hard-core repulsion between spherical nuclei
generates only the bulk (volume), surface and curvature parts of the free energy of the nucleus, while the Gaussian
curvature one does not appear in the derivation. The phase diagram of nuclear liquid-gas phase transition is studied for a
truncated version of the developed model
