Earlier quoted context omitted.
NASA is working on it, but until there's a working engine available for private rockets it seems premature. https://www.nasa.gov/centers/marshall/news/news/releases/201...
Ordinarily I would agree. However, this is Musk, and both SpaceX and Tesla have made progress beyond what most commentors have thought reasonable when the first press releases went out. I’d guess a 10%-30% chance SpaceX is already Skunkworks-ing some form of atomic rocket, either fusion or fission. Edit: and yes, that estimate is despite the public comments.
Well you and I are just speculating, so who knows. But I sort of doubt it. People would have noticed if SpaceX was hiring nuclear engineers. I think they have enough R&D on their plate getting to full reusability.