I been spending a lot of time looking into that whole Daiichi disaster, what a big scary mess

the impact from that place will likely be ongoing for a very I long time, we as a species need to find a better way to boil water...
The real problem, like everything else, was they didn't want to spend money to fix the problems that inspectors warned them about.
Mosts Plants have a cooling system with 2 or 3 back up cooling systems. The pumps in all these systems have back up power to keep them running in case of loss of power. Power from the grid, and at least 2 diesel generators, per reactor, back up the power to these pumps.
First thing is any natural disaster like earthquake, flood, tornado, etc and the plant shuts itself down.
If plant shuts down and or power from grid is lost, the first diesel kicks in. If that diesel goes out the second one kicks in.
The diesels are underground, I been in some that were 7 stories underground. These underground bunkers are supposed to be sealed so flood can't hurt them.

So far so good.
First the exhaust has to be vented above ground.
And the heat is pretty intense in these bunkers so the oil
tank & gas
tank had to be put into separate bunkers.
Plants put the oil & gas
tank bunkers above ground as well and they were vented to let fumes out.

Vents to let air out can let water in.
Water, especially salt water, mixed into the diesel oil or gas is very bad
Fukushima got hit with a tsunami before so they knew how high the water level could go.
This design mistake was pointed out years before the Fukushima accident and they were warned to raise and or waterproof these systems. But that would of cost money... Besides the whole grid would have to go down plus lose power to 2 separate diesels, and that would be like a million to one chance of that happening

But if by some freak of nature that did happen, they did have a back up back up to the back ups

They could always bring in mobile generators.

Mobile generators look great on paper so there was no need to worry.
But again, it would have cost money to mod the plant to be able to plug them mobile gens in

Opps
