Cooling down the Fukushima reactors?

I was thinking about this, they need to cool down the reactors fast, but looking at things it seems that the possibilities are low. I was thinking they could "try" to make a controlled "mini tsunami" [is it possible]like detonating a bomb a few km of the coast since the Fukushima nuclear plants are almost at sea level [ i think] it would not need a very huge wave [maybe 6-8 or a bit more meters high] this would make the reactors unusable but stop major radiation, haha i know this idea sounds kinda stupid but they probably wont be able to do much more, they are pumping water to one of the reactors and dropping water on another [ i heard on the news that the helicopter that drops water just helps maintain the temperature but not lower it]. Will both reactors eventually explode?