  We study the effect of the exchange interactions in small superconducting
grains near the Coulomb blockade regime. We extend the standard description of
the grain in terms of a single collective variable, the charge and its
conjugated phase, to include the spin degree of freedom. The suppression of
spin fluctuations enhances the tendency towards Coulomb blockade. The effective
charging energy and conductance are calculated numerically in the regime of
large grain-lead coupling.
