I have a question about nuclear weapons. Anyone here know much about them?

[PamW]

77. Perhaps I can answer for you

Spent fuel needs to be actively cooled for a few months after being taken out of the reactor.

It all depends on what happened to the people, and when with regard to the de-fueling of the reactor.

If the reactor was de-fueled recently, and people just disappeared; then we would have the Fukushima scenario.

However, if it's been more than a few months; reactor's get refueled evey 12-18 months; then the need for active cooling will have subsided and there won't be a problem.

I wouldn't put too much stock in the "Life After People" TV series; they get lots of stuff just plain WRONG. Look at them as "entertainment" but CERTAINLY NOT as a scientific reference.

Jeff - you are wrong about there being nothing like control rods in the pools. YES there is.

The pools have little "cubby holes" to put the spent fuel assemblies in. The walls of these cubby holes are made with steel that is borated. In essence, the walls of the cubby holes are like control rods - but even better. Rods can't fully prevent neutrons from one assembly from transporting to a neighboring assembly. But a solid wall of borated steel sure can. So the fuel pools have something like "super control rods".

The reason Yucca and dry casks don't require cooling is that the fuel only needs cooling a few months. The fuel isn't put in either Yucca or in dry casks until the heat production rate has dropped by natural decay to the point that you don't need active cooling.

Hope that's educational.

PamW