Dude, there is a HUGE difference between Operator Plant Trainee and Initial License Trainee (ILT). The first is non-licensed, or NLO (as TVA said). You'll be brought in, probably at the lowest payrate and (usually) get raises for each qualification you complete until you top out. Depending on how they have it set up, it could be 2-3 years. The plant I'm at is about 39 months for an NLO starting at step 1 (Intro to plant systems/fundamentals), if you're brought in at a higher level, the starting pay is higher, but you have less time for the earlier levels, so instead of 3-6 months for each step, you might have 2-4 weeks, until you're up to your pay grade, then it goes back to 3-6 months. These guys are the eyes and ears of the plant, and most plants want them to go on to ILT to earn an RO license once they're done with NLO quals (that will add usually $5-10/hr raise, plus license bonus). If you were in the navy, basically all the MM and EM watches combined.
ILT is about 2 years of classroom/simulator training with some plant time for familiarity before they earn their license. These guys run the plant from the control room, make decisions about what goes on during the shift and direct the NLOs. ROs control the reactor and associated equipment, SROs direct things. Again, if you were navy, RO for RO license, and EWS/PPWS/PPWO/EOOW for SRO license.
