The biggest change will probably be the importance of the paperwork, from quality assurance testing requirements, required hold points for witnesses to observe certain actions, to every single change from the construction drawings requiring formal review and approval. Productivity will in all likelihood be an order of magnitude less than what you are used to. You might also try to hook up with a company like Bechtel or Shaw for some of the smaller nuclear projects they have going on now (outage modification work, steam generator replacement, etc.). Typically, each nuclear plant has an outage with at least some construction activities every 18 or so months. If you can get in, it's a good way to get some nuclear experience.