Massive quake hits Japan; Tsunami in Pacific, nations on alert

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Originally Posted by Mattyk

It takes so long because even when they shut them down they keep generating heat. Kind of like when you turn off your oven and it takes a while to fully cool down.

I realize they retain heat but they must also keep producing heat for some period because of how much time has passed and they are still that hot. The only other thing I could think of is that they have to lower the temp slowly to prevent cracking issues.