 Radiation shielding effectiveness increases exponentially with shield thickness, see gamma ray for a discussion of shielding.On ships with a mass greater than the structural bulk of the ship, its stores along with the mass of the bombs and propellant, would provide more than adequate shielding for the crew.Stability was initially thought to be a problem due to inaccuracies in the placement of the bombs, but it was later shown that the effects would cancel out.