Yep.
Besides persuading the best physicists to "self deport" German graphite has a trace, just a whisper, of neutron absorbing boron.
The remaining racially pure Nazi physicists built graphite moderated test reactor, ran tests, and concluded that the idea was impractical...
That’s fascinating if such minute quantities of boron are enough to actually kill a reaction. Aryans aren’t either particularly stupid or particularly bright, but it’s notable that the scholasticism of science has featured a lot of Jewish people. Jews are a bookish people by faith. From partial Jewish background I can vouch that Jews are some of both the brightest and most stubborn people in this world.