  In this paper we show that BF topological superconductors (insulators) exibit
phase transitions between different topologically ordered phases characterized
by different ground state degeneracy on manifold with non-trivial topology.
These phase transitions are induced by the condensation (or lack of) of
topological defects. We concentrate on the (2+1)-dimensional case where the BF
model reduce to a mixed Chern-Simons term and we show that the superconducting
phase has a ground state degeneracy $k$ and not $k^2$. When the symmetry is
$U(1) \times U(1)$, namely when both gauge fields are compact, this model is
not equivalent to the sum of two Chern-Simons term with opposite chirality,
even if naively diagonalizable. This is due to the fact that U(1) symmetry
requires an ultraviolet regularization that make the diagonalization
impossible. This can be clearly seen using a lattice regularization, where the
gauge fields become angular variables. Moreover we will show that the phase in
which both gauge fields are compact is not allowed dynamically.
