Time dependent models for Li, Be and B production in the early Galaxy

We calculate the light element production induced by the explosion of an isolated supernova in the ISM. We use a time-dependent model and consider energetic particles accelerated at the forward (process~1) and reverse (process~2) shocks. Both processes are primary, but are shown to underproduce Be and B. The reasons for this failure are analyzed and used to propose a possible alternative, based on the acceleration of particles inside superbubbles.