Sir:
It would appear that very low levels of radioiodine (I-131) have been detected in Western US milk, as could be expected.
Presently, the contamination from Fukushima is taking over a week to cross the Pacific, and that time, combined with dilution effects, reduces the contamination from the Fukushima disaster to point far below the level of concern. At the present time. It also appears that the fukushima fallout plume is not rising high enough at present to become entrained in the jet stream
However, reports from Fukushima, and analysis of the data available, indicates that a containment breach may have already occurred, and that it is possible that re-criticality events have already occurred in the melted reactor cores. Assuming that the emissions of radioactive material from the former Dai-ichi nuclear plant do not significantly exceed their present rate, it is likely that this will remain a largely regional horror. The Japanese continue to place their power plant workers, and military and construction teams assigned to the Fukushima site, in harm’s way to attempt to prevent this from further deterioration. And these people continue to be willing to risk their lives and suffer significant exposures to do so. Take a moment to keep these people in your thoughts and prayers; they are truly heroes.
However, should the re-criticality inside any of the damaged reactors accelerate, and make the immediate area around the plant unsurvivable, the spent rod pools (#4 is at greatest risk) will dry out, and could also melt and suffer re-criticality (keep in mind that there are over 800 tons of recently used spent fuel rods stored on site, with another 6,000 tons of older used rods stored in a common fuel storage pool.) The spent rods have no robust containment at all.
The radioactive release from such an event would dwarf Chernobyl, and while the fallout from such an event would probably not be serious here in the USA, (absent a large enough plume to be carried across the Pacific in the jet stream,) the deposition of Sr-90 and Cs-137, which substitute for calcium, would pose a potential health risk, especially for children and women of child-bearing age. If you have not already purchased a supply of powdered milk, I suggest you consider it, especially if you have small children in your household. – L.M.W.