[pooloo1]

High ASVAB scores really is about it, and even that is waivable. After they go through boot camp, they will generally get filtered out through attrition at their respective A-School (training school), which is why the requirements can be waived, and they go to a new job.

[brandmeyer]

Very much unlike college admissions (where it's relatively hard to get in, and also hard to flunk out of), it is relatively easy to get into and and also easy to flunk out of the enlisted nuclear program. In my class, the failure rate was about 60% overall, and I think that's pretty typical. They start the failure process pretty early, too, starting with the first round of exams. The Navy is happy to find you another job that isn't quite as demanding. Most of the non-nuclear submariners I worked with were "failed" nukes. In college, it seems like folks are more likely to fail out completely then they are to fail into a less demanding degree that they could still succeed in.