I mean, the information is out there. The people who really want it already have it. It's not some massive secret. It really doesn't matter if Claude can or can't tell you how to build a nuclear bomb, because people already know how to do it.
The problem is that you need the power of a state or a massive corporation to come anywhere close to getting the materials to make a nuclear bomb. Knowledge of how to make a nuke isn't the threat.
If AI is a threat at all here, it would be in figuring out a simpler way to make a nuclear bomb, but that is highly theoretical, so what exactly are we putting up guardrails to protect against?