For nuclear detonation to occur, a substantial fraction of the energy in the fission trigger must be released in a geometrically controlled way over just a couple of milliseconds. Anything else and the bomb core will destroy itself before it can complete its business, be that directly creating a fireball and blast or triggering thermonuclear fusion. If you set such a weapon on fire, hit it with a sledge hammer, drop it out of an airplane, or nuke it, you are absolutely certain to damage it before it can go off. The worst you are going to do is release radioactive materials into a fire, where they might be spread around in the smoke.or blow it up with a smaller bomb!