No. Just no. Let says that the japanese reactors, all four of them, went super critical. The worst case, they would have to encase the reactors in concrete and leave them alone for a few thousands of years.
But the reactors, all of them, are being cooled, there is nothing stopping them from taking care of this mess. The amount of radiation leaking into the ocean is less then the radiation from the nuclear waste, in barrels, we dumped off California in the 1950-1970's.
If the reactors went critical, the west coast would not have to be evacuated. About 30 sq miles around the plant would have to be, but no more.