true, but this is asking if they can construct one, not detonate a fission reaction.
I dont think its that far of a stretch that even an explosion magic user could explode it if they got their hands on some weapons grade uranium
Ah, well then still probably. Theyâd just need some way to, most likely magically, automate their spirit weapon. Though that would still require some knowledge of engineering that seems beyond the scope of any of the Sea Clusters.
Edit: Okay, reread the initial question, and I donât think so. While they can almost certainly perform fission through their own ability, I doubt it would be possible to summon a fully formed atomic bomb. Given the energy it would take to form such a device, it would most likely kill the Oracle before they even get the chance to detonate it. Thereâs also the problem of detonation, it wouldnât be effective in combat given the fact that either you donât get enough energy to set the bomb off, or you just kill yourself in the blast. Overall itâs just too ineffective and dangerous for any Oracle to truly consider.
suicide bomber oracle that just wipes an island off the face of the earth
They would need to know how to make a nuclear reaction at that scale first 
Time for the scientific arc
WoM folks SHOULD know how to make a nuke.
In fact they should have known for a long time, given just how much time passed.
would manipulation over electrons really grant you control over the entire electromagnetic force though?
ânice argument, small issue, reassembles your particles into an armchairâ
Thatâd be Helios!
wouldnât that be fusion
heâs the god of hydrogen bombs
idk why but this just reminded me that canonically in Percy Jackson universe, Zeusâs lightning bolts make hydrogen bombs look like firecrackers
ah yes, the master bolt
truly SHOCKING
Future spirit weapon perhaps? 