training for an ETN is an oral board where an ETN must demonstrate the knowledge of all procedures, equipment, theory expected for a nuclear reactor operator. Completion of NPTU qualifies an ETN to stand watch on the NPTU or to train to operate nuclear propulsion plants on a nuclear aircraft carrier or submarine. Additionally, it gives the individual the ETN Navy Enlisted Classification (NEC), and the individual is then said to be "nuclear qualified." Upon completion of the Naval Nuclear Pipeline, most nuclear qualified ETNs are sent to nuclear aircraft carriers or nuclear submarines. On a nuclear-powered aircraft carrier, ETNs are sent to a nuclear training division where they train to qualify to operate the nuclear reactors of the ship in a similar way to NPTU for about six months prior to being sent to a reactor control division. In contrast, on a submarine ETNs are directly assigned to the Reactor Controls division and are directed to qualify different watches incrementally. Due to the smaller number of personnel on a nuclear submarine, ETNs must also cross qualify on several nuclear electrician watches. Since ETNs are required to stand watches, perform maintenance, and train and qualify on additional submarine systems, it is not uncommon for it to take over 12 months for an ETN to become fully qualified as a reactor operator, shutdown reactor operator, and all intermediate watches. Upon subsequent transfer to an NPTU or another nuclear ship, operators are required to re-qualify the same watches in only about 6 months. Even upon completion of being fully qualified on all ETN watches ("qualified in rate"), additional proficiency and casualty training is required for all ETNs. On a ship this generally includes general Engineering or Reactor Department training, Reactor Controls division training, periodic exams and interviews, monitored maintenance and operations, periodic watch re-qualifications, and monitored tactical or casualty drills. Usually after an ETN is "fully qualified" the individual is sent to an "in-rate" technical school ETMS where the technician studies electronic troubleshooting and repair on shipboard equipment. Completion of this school allows the technician to be designated with the NEC 3373. Senior ETNs (typically those who hold the rank of petty officer first class (E-6) or higher) are expected to qualify for senior supervisory watches. Self-motivated training for this includes the detailed operations of all nuclear systems on a ship (not just the ETN specific parts) focusing on the big picture