It depends on what you mean by middle. If you mean just placed in the middle of the configuration, probably not much. A few feet of concrete reinforced steel ca

It depends on what you mean by middle. If you mean just placed in the middle of the configuration, probably not much. A few feet of concrete reinforced steel can resist a lot. Certainly some leaks but probably not too bad outside of the immediate vicinity. If you put the bomb in the middle of one of the casks, it would probably impact 100,000s of people. It'd probably be pretty hard to get it there though and if you could do that, you could probably extract the radioactive material and transport it somewhere else.