A hydrogen bomb, such as the W-76, is a two-staged device. The first stage sets off a high-energy explosion, which in turn triggers a fusion implosion. The first-stage blast is not very powerful. The precise number is classified, but it's in the range of a few kilotons (the blast-power of a few thousand tons of dynamite). The second, fusion stage, is what boosts the power of the bomb—in the case of the W-76, to 100 kilotons. (Some fusion, or hydrogen, bombs implode with the force of megatons, or millions of tons.) The two stages are connected through an "inter-stage coupling process," which involves X-rays irradiating the plasma sphere containing the material that implodes. This process causes considerable vibration. Some weapons scientists claim that the W-76's casing is so thin that the vibration would prevent the process from being completed. As a result, the W-76 would explode with the force of only a few kilotons (the first-stage high-energy blast), not 100 kilotons—not enough to destroy targets of substantial size or even modest blast-resistance.