  In this paper we investigate the saturation physics in diffractive deep
inelastic electron-ion scattering. We estimate the energy and nuclear
dependence of the ratio $\sigma^{diff}/\sigma^{tot}$ and predict the $x_{\pom}$
and $\beta$ behavior of the nuclear diffractive structure function
$F_{2,A}^{D(3)}(Q^2, \beta, x_{IP})$. Moreover, we analyze the ratio
$R^{diff}_{A1,A2}(Q^2, \beta, x_{IP}) = F_{2,A1} ^{D(3)}/F_{2,A2} ^{D(3)}$,
which probes the nuclear dependence of the structure of the Pomeron. We show
that saturation physics predicts that approximately 37 % of the events observed
at eRHIC should be diffractive.
