He would not have succeeded in making a real reactor even with AI, because AI can't magically give you a large quantity of uranium metal! JFC the AI hysteria is unreal.
Step 1. Obtain pliers
Step 2. Obtain 300 discarded smoke detectors
Step 3. Start yanking!
You'd maybe get a sketchy but near-viable plan that could be dangerous if asked for a dirty bomb, but there the danger would more be the conventional explosives and not where to source radioisotopes, as it was already common knowledge that most residential smoke detectors contained americium until recently.
The concern here is not if an amateur attempt to make a reactor, hack a bank, bioengineer a medicine/poison is successful or not. Interactive and instructive access to some forms of knowledge used to come with discretion along side instruction.
Yes, perhaps your swearing at me in this context is a little hysterical