Another update has come out from official Japanese sources. They have finally started pumping more seawater into the cores of Units 1, 2 & 3 to raise the water level to cover the fuel rods. Amazingly enough, they have had the levels from 1,300 mm to 2,300 mm below the top of the rods!!! The temperatures have dropped, the oil fire burned itself out and they have regained momentum in gaining control. The radiation has been mostly volatile iodine (gas state), not particulate cesium (fine solid state). The convective force has been too small to loft the cesium, so the principal radiation issue is the iodine, which has a half-life of 8 days. What cesium got out would have been when they vented the reactors and experienced the hydrogen explosions, or when the spent fuel ponds were very low on water. Both have not been an issue for days and are unlikely to recur. So we are past the peak of the radation plume and it will die down by one-half every 8 days. So in two months, it will be less than one percent of what it is now.