It did work then, and will work better now, because back then, people had to fly it. They would have gotten radiation poisoning. Now, we can design electronics to work in large neutron fields. I have designed electronics myself that would survive a 1Mrad dose. It can be done. They could do it.
If you consider a 22 mile range as a threat, your call.
As an aside, any (ICBM) re-entry vehicle would considered hyper-sonic, so the idea of a nuke powered, air-breathing, cruise missile as a alternate system is a tad...IMO - ludicrous.
YMMV