[Henk]

If they don't get them restarted right away (4 to 6 hrs) they will have to wait for about a day (i think) before they can be restarted due to Xenon-135 dead time.

See this link.

[TexRef]

[snopercod]

I love it when you talk technical.

Actually, it will probably take three days for the Reactor Operators to remove the seat cushions from their hindquarters.

A 100% load rejection at a nuke plant is spectacular. I have stood and watched a major steam dump at Diablo Canyon and it shakes the very foundations of the earth.

[bagman]

Xenon dead time depends on the type of plant and how long the core has been burned (at least for a Pressurized Water Reactor - a majority of the plants in the USofA are pressurized water reactors). Early in the fuel cycle, xenon dead time isn't going to happen. If the plant trips near the end of its fuel cycle (plants these days typically run an eighteen-month fuel cycle between re-fuelings), then xenon over-ride can be somewhat more difficult.

I suspect that these plants were all scrammed (rapidly shutdown). The biggest constraint on re-starting, I would guess, is going to be whether the grid is restored and stable for the individual plant and how long it will take to work through the necessary paperwork. I'll bet most of the plants are coming back on line by Friday afternoon. It will take some time, then, to reach full power.

[70times7]

This may have been addressed elsewhere, but I'll post it anyway. There is a big difference between the reactor being down and the facility being down, as in not supplying power to the grid. I'm no expert, but I can't imagine those facilities would be built without a way to dissipate the heat without running the turbines.