Sure. Nuclear security is a broad area and it can mean a whole lot of things, but mostly it means more to do with non-proliferation and defense against and resp

Sure. Nuclear security is a broad area and it can mean a whole lot of things, but mostly it means more to do with non-proliferation and defense against and response to nuclear threats on a technical level and less the mechanics of training people what to do in the event of a detonation. It'd usually fall into the spectrum of nuclear engineering, though it can be pretty multi-disciplinary (e.g., my educational background is in nuclear engineering, applied math and CS). In my case I'm in research; specifically I develop algorithms for locating radioactive sources using sensor networks distributed through a city. My educational background focused heavily on non-proliferation and nuclear forensics. One of the things we studied in my graduate career was how to optimally sample fallout in the immediate aftermath of a detonation based on predicted dispersal in order to get the best quality samples (for forensics work) while minimizing the risk to first responders. Spent a decent chunk of time learning about all the sorts of dangers you expect from a nuclear detonation.