There's a general consensus, except on Fox News, that the radiation from Fukushima will not reach the United States. You can read any number of informative diaries on why Fukushima is not Chernobyl.
However, if you're still worried, I have a simple one step plan below the fold.
Step 1) Go to Wisconsin.
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Even the most wide-eyed doomsday scenarios don't show dangerous amounts getting past the Rockies, so you don't need to worry under the swaying palms of scenic Wisconsin.
And, in the mean time, you can help with the protests in Madison. Or the embattled city of your choice, if you have somewhere with friends or family.
I'm a worrier myself and there's nothing better for it than turning that energy to something productive. Regardless of the outcome of this disaster and whether it effects us directly, we need good governance going forward. The plutocrats aren't helping the citizens of Japan and they aren't helping us.