The Atomic Enricher technology requires cryogenic science to unlock, however the Fission Reactor, Portable Fission Reactor and Atomic bomb now all require the Atomic Enricher, which in turn means you cannot make a fission reactor until after Aquilo and you have unlocked fusion power...
I think this is because you have created the new "advanced-centrifuging-or-crafting-or-electromechanics" recipe type, but not added it to the centrifuge.