  The dynamical generation of wormholes within an extension of General
Relativity (GR) containing (Planck's scale-suppressed) Ricci-squared terms is
considered. The theory is formulated assuming the metric and connection to be
independent (Palatini formalism) and is probed using a charged null fluid as a
matter source. This has the following effect: starting from Minkowski space,
when the flux is active the metric becomes a charged Vaidya-type one, and once
the flux is switched off the metric settles down into a static configuration
such that far from the Planck scale the geometry is virtually indistinguishable
from that of the standard Reissner-Nordstr\"om solution of GR. However, the
innermost region undergoes significant changes, as the GR singularity is
generically replaced by a wormhole structure. Such a structure becomes
completely regular for a certain charge-to-mass ratio. Moreover, the nontrivial
topology of the wormhole allows to define a charge in terms of lines of force
trapped in the topology such that the density of lines flowing across the
wormhole throat becomes a universal constant. To the light of our results we
comment on the physical significance of curvature divergences in this theory
and the topology change issue, which support the view that space-time could
have a foam-like microstructure pervaded by wormholes generated by quantum
gravitational effects.
