[teh_klev]

But the problem isn't nuclear detonation, it's about using the weapons as a dirty bomb:

With a few hours and the right tools and training, you could open one of nato’s nuclear-weapons storage vaults, remove a weapon, and bypass the pal inside it. Within seconds, you could place an explosive device on top of a storage vault, destroy the weapon, and release a lethal radioactive cloud.

[mikeash]

Those are two separate ideas. You don't need to bypass the PAL if you just want to blow it up conventionally to spread radioactive material around.