I guess one big advantage of blockchain technology in military and defense force is having a secure data. We all know that military decisions on based on accurate data they have in hand in real-time. So if having taken advantage of this technology to help them make critical decisions, specially in life and death situation.
So perhaps the government is also taking steps to protect critical nuclear US defense system. So its possible that they are looking at blockchain technology to closes those gaps as well.
Blockchain technology being used to secure nuclear weapons could be interesting though. I'm picturing something that involves multi-sig, and there are several people who need to agree with it before they can activate something.