[pharmablogger]

Sure they aren´t like A-bombs, but i´ve read that they do release a pretty fair ammount of radiation on impact.

You've perhaps misread the term "radiation" in the context is was used in - for example, radiation is often applied to electromagnetic waves. Although asteroids certainly contain radioactive elements, they don't carry anything near the quantity or type necessary to initiate a mass burst of nuclear radiation upon impact. The heat from the collision might cause some fusion to take place but, again, it wouldn't cause serious amounts of radiation.