Wednesday, March 16, 2011

Nuclear Situation in Japan

A few people have asked me to comment on the potential for public harm and the reactor situation in Japan, because of my background. I would like to make clear that my experience is with an entirely different type of reactor. Further, I don't think we are getting accurate reports from either the Japanese government nor the power company that runs the reactors, making transoceanic commentary problematic. However, I would urge my friends and readers not to panic. Taking potassium iodide prophylactically is unhealthy and an unnecessarily risky. In the highly unlikely event that a plume of radioactivity could transit over the 5500 miles of ocean between San Diego and Japan, then some precautions might be called for. However, rain and natural particulate fallout would likely drastically reduce the effect of such a plume.

I am neither an opponent nor a proponent of nuclear power. Its use should be a business decision that trades off cost and risk, like any other project. The disaster in Japan points up the added risk of centralization of power production, especially near the coast. Further, centralizing power production puts risk into a fewer number of baskets.

With regards to the safety of nuclear power, I can only say that this earthquake was of magnitude 9, not unprecedented but extremely rare, or so says Robert McCaffrey in Geology magazine.
Given multicentury return times of the greatest earthquakes, ignorance of those return times and our very limited observation span, I suggest that we cannot yet make such determinations. Present evidence cannot rule out that any sub- duction zone may produce a magnitude 9 or larger earthquake. Based on theoretical recur- rence times, I estimate that one to three M9 earthquakes should occur globally per century, and the past half century with five M9 events reflects temporal clustering and not the long-term average.

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