San Onofre shutdown will mean tight electricity supplies

[FBaggins]

87. Yeah... it's Yellowstone.

The whole thing is one massive volcano. When it blows (as it eventually must), half of us in the US are likely dead... and the rest will be pretty miserable for a long time.

The rest of your post, thought, is mistaken

the way the site is cut into the bluff there is nowhere for that wall of water to go except to pile up against the bluff.

That's not how hydrodynamics works. The wave would reflect off of the solid bluff/seawall

Those diesel generators would no doubt be swamped if hit by a tsunami like what hit Fukushima.

Nope. Unlike Fukushima, they're in waterproof vaults and can run while submerged (and the switching equipment is much higher up)

If a nuke plant loses offsite power and its onsite backup power a meltdown is a likely outcome.

If it loses offsite power and four backups and batteries and mobile backups very quickly after shutdown?... probably.

I really dont know how the site passed the tsunami scenario.

Because the site isn't prone to significant tsunami... and the largest plausible tsunami from a distant source was determined to be 20'... when the seawall is 30' above low tide.