(Hence why I think he's 'learnt' the basics about fission and now refuses to consider learning the basics about fusion, because "he now understands everything!", and doesn't need to learn any more.)
I can certainly assure you he's either never been to a college physics course, or didn't pay attention.
I don't think it's even college level, at least not in UK terms. I think I was taught
1 about fission (
and fusion) in secondary school (tops out at age 16), and at Sixth Form College (the usually two years of pre-university non-compulsory education) the Physics probably went more into the maths and details, but didn't vastly change my basic impressions.
But I have difficulty enough working out how my 'old-style' year-of-school designations compare with the various numbers in the "K-12"-ish form now being used, over here, and the US form of "College" seems to be an entirely different span of ages.
But "not paying attention" covers a multitude of sins and (willingly or not) I assume that's what happened in this case.
1 This being a different time from having
learnt about the subject. I'm sure I'd been to nuclear power-station visitor centres
2 even before I attained a double-figure age, certainly before I got to secondary school.
2 Always fun, with loads of 'interactive' exhibits demonstrating things in button-activated back-lit diagramatical form... Much more fun than stately homes full of boring old furniture that you're not even supposed to touch. Although a good largely-ruined castle with enough spiral staircases and rebuilt stone stairways to make the crenelated battlements accessible (with just the bare amount of modern safety barriers) is good, too.