  The formation probability of quark-gluon plasma in relativistic heavy ion
collisions for colliding nuclei of different sizes is investigated in the
framework of a bond percolation model. The results show that nuclei with sizes
smaller than that of Pb or Au produce QGP with probability less than unity even
at very high collision energies. The dependence of the QGP-formation
probability on different nuclear sizes and on various centralities of Au-Au
collision are presented.
