I can tell you work in the private sector as an I&C tech. The nuclear world's a little different. It's governed by statutory requirements so it doesn't matter what the economy is doing. Do you get an annual checkup? Do you care what the economy is doing when you get it? This will be important to remember if you want to do outages only. If I were new, just getting started, go ahead and take the ISA test, it can't hurt. Then, instead of being a roadtech like a lot of us baby boomers did, I would try to land a job with one of these specialty I&C contractors that serve as vendors to the nuclear plants, they keep you busy year round and have benefits. The outages are awfully short, and if you go it alone, you almost need a travel agent to keep up. The fossil guys do this and travel 3 weeks here, 3 weeks there. We never had to do this years ago. We stayed for several months to a year at a site.
I would try cyber security as a specialty, if you have the computer background and can get into it. I think it has a great future in these plants. Turbine overhaul crews is always good. PLC vendors also, since you come from the private sector and already have this.
The future looks good for I&C techs in nuclear. What will change is how you go about keeping busy at it.