[glock rocks]

The gen-sets were knocked out, but the reactors were in cold shutdown for maintenance so they didn't need the additional cooling.

After the quake, the control rods dropped and ALL the units were in "cold shutdown." However, cooling must continue as heat is still generated by the deterioration of the remaining byproducts of the reaction. Hence, all reactors (except 4, which had no fuel rods in the reactor), and all the spent fuel pools need continuous cooling.

[meatloaf]

The control rods on a BWR are inserted from the bottom of the reactor.