Putting the word "nuclear" in the middle seems to just be done in textbooks and classrooms.
It's something you never get used to. As you get older, this will just keep happening. We used to put commas before the last item in a list back in like the stone ages when I was in school. My SAT score looked really lame for a bit of time when those suddenly changed.
I understand the grumpy old person archetype now. I feel like I've been one for a long time, but it's really hitting home over the past decade.