My boat had a 6 foot 7 inch tall ELT. I was a LELT on a boat. You'll do radiation surveys, chemistry samples on the reactor side and on the secondary (non radioactive side), you'll trasfer radiactive material from place to place, you'll perform decontamination of areas that get radioactively contaminated, you'll process radiation dosimetry, you'll do maintenance on chem lab equipment, you'll stand regular watches assuming you go to a submarine, you'll be the first guy into the reactor compartment and the last one out.
If you go subs you'll do all the cool machinist mate stuff too.
Mike