I think it would depend what sort of penetration you're after.
It was not possible to work with robots in/around the reactor in the immediate aftermath of the accident -- the robots would fail due to exposure to the radiation. It's quite possible that technology still hasn't advanced far enough to allow for the in-depth exploration that would be required to achieve anything like the linked example.
I'd be curious to know if anyone knows more about recent attempts and the state of the art of hardening robots, drones, computers, etc. against radiation.