This is yet another reason why nuclear is not the answer to our future power source. Quite apart from the fact that that it is a dangerous and not fully understood material, it is not better for the environment. I'm not talking about meltdowns here either. Plutonium is particularly difficult to extract and resides in inaccessible parts of the globe. So by the time it reaches its intended destination it has already done significant environmental damage and amassed a large carbon footprint!