And the SSBN Security Program Office funding got quadrupled immediately afterwards, just to keep the smug little so-and-so running the place (who most folks believe gave Red Cell some detailed scoop about procedures) from saying "I TOLD YOU SO" to Congress.
Forgot the guy's name (it wasn't DeMars, he replaced Rickover at Naval Reactors) but the Admiral at SSPO back then was a bureaucratic fighter par excellance, and he got what he wanted--a TON of stuff to stop an attack with. BTW, I seem to recall that Marcinko's folks swam on up and didn't jump.
I am more worried about them jumping onto an LNG tanker 15 minutes from port and ramming downtown at 25 knots.
15 minutes out, that bad boy is going to be in the hands of the tugs and just about pierside...the only way you'd get it up to 25 knots is with a Saturn V first stage. But just blowing it up pierside would be bad enough--the LNG facilities ashore would probably go in a sympathetic detonation, and you'd probably go up to the ten kiloton mark right there. Don't need to get it downtown then, you've probably wrecked the entire waterfront. And for that, you don't need the complication of an airborne assault--just get people inside the fence at the LNG facility.
Or jumping right into the center of a nuke plant and destroying the backup generators and water pumps.
The only effect of this at a U.S. commercial plant (or even a weapons plant) would be to trash the reactor core itself--the only way you get a meltdown sufficient to blow out the containment is with reactor fuel that's already bomb-grade to start with. The only folks crazy enough to do that are Russia and China--Russia doesn't believe in containment, and China likes the high energy density you get from bomb-grade fuel. Of course, if they ever have an oopsie they're going to have generations of FLKs...
Have you read about the arabs in the fake USCG boat in West Va casing the chemical plants? No urban legend, I'll ping you.