121X Nuclear Power School-Instructor (RL)

In the United States Navy, 121X is the officer designator for a Nuclear Propulsion Training Officer (Nuclear Power School Instructor). Nuclear Power School Instructors work with Nuclear Propulsion Officer Candidates on advanced math equations.

Other officer designators in the Navy include: 122X - Nuclear Engineering Officer (Naval Reactors) 123X - Permanent Military Professor (RL) 130X - Air Warfare - Pilot or NFO

You can become a Navy Nuclear Instructor by being accepted into the NUPOC program.