>nuclear technician training in the Navy is very, very difficult to pass.

Rigorous, yes, but not "very, very difficult to pass". The Navy needs a consistent stream of replacement operators, and their preferred way of getting them is to take reasonably capable volunteers and tutor/coach/remediate as many people as needed once they're in that group.

As someone who was a reactor opreator in the US Navy I'm laughing my ass off at this: "very, very difficult to pass". 90% of the people I started training with were gone in the first two years!

> 90% of the people I started training with were gone in the first two years!

My experience too. Do you remember the "skyhook"? We'd return to the barracks after class and find that the guy next to you had vanished without a trace.