Youve missed a major point that I was trying to make. All existing nuclear bombs are essentially BINARY explosive devices with an initiator which begins the neutron release, which then triggers a fission reaction. ITS EASY TO KEEP THESE BINARY SYSTEMS "QUIET". In a nuclear plane or rocket, there is no binary safety system. The nuclear fission reaction is ALWAYS ON because thats what makes the damn thing work.
While the scince is pretty much the same, the rationale for controlling the reaction is entirely different in a nuclear rocket.
As far as safety, I have about 30 years in the nuclear mining and processing geo field. The isotopes posiible from a specific fission reaction are many. If an in flight accident happened (mort tables say that they would occur based upon the 2 shuttle and several Russian and American disasters). One accident could spread radiation over several tens of square milkes minimum. YOU cannot deny that this is a high possibility. Trying to discount such an eventuality is playing with a revolver with one bullet.
If you dont believe me, why isnt the world scrambling to develop nuclear rockets for their space programs??
SAFETY CONCERNS PRIMARILY.
There'v been so many scientists who commented on these safety concerns ( I sit on a peer review committee re: ground water cleanup of "Mixed wastes") and our biggest concern in almost any technology is safety and guaranteed safety.
Youre trying to pitch "perpetual motion" Bill.