Monday, March 14, 2011

More on rare events

AP Paris -- "“Europe has to wake up from its Sleeping Beauty slumber” about nuclear safety, Austria’s Environment Minister Nikolaus Berlakovich told reporters in Brussels. He suggested an EU-wide stress test for nuclear plants, much like European banks have been tested for their ability to cope with financial shocks. Yet some experts and officials say those fears are overblown, given the exceptional nature of Japan’s earthquake and ensuing tsunami. The Japanese blasts may slow the push for more nuclear plants, but appear unlikely to stop it, given the world’s fast-growing energy needs."

"exceptional" = roughly one-in-twenty-five odds, in the present case, according to historical records of natural disasters in Japan.
How many once-a-millenium events are dismissed in various countries when designing nuclear power plants, because of their "exceptional" nature?

What Yuval Peres was telling me today: that people cannot distinguish between odds of one-in-one-hundred and of one-in-one-million. That's why there is every reason to be worried about current safety measures everywhere. The last sentence of the AP article reminds me of a XIVth century French proverb: "Il n'est pire sourd que celui qui ne veut pas entendre" [No one is deaf like the one who does not want to hear].

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When I go into the mountains with my son, sometimes we go to exposed locations. At this point he is more nimble than me and I cannot protect him physically; but I always remind him: "Here, you must not fall. Don't go there if you're not sure you'll make it. Don't go, even if you think that the odds are 9 in 10 that you'll be fine. Even 99 out of 100 is not good enough, since that would mean that you would fall after we've gone mountaineering for a hundred times or so. In this instance (say, walking on top of a cliff with a tremendous drop all but guaranteeing death in case of a fall, for example), I don't want you to fall, not even once." --- of course the safer option would be not to go mountaineering at all, but life would be pretty dull if we could not do the things that bring us the most joy; so there's some amount of risk that we're willing to take. I know that there is a risk, I hope that it is minuscule, and I trust that my son knows how to gauge it. Mountain guides: that's one profession where they have to know how to assess risk if they want to grow old.

Meanwhile, a few proponents of nuclear energy are admiringly drawing attention to the 50 Japanese plants that did not cause any trouble in spite of the earthquake and tsunami. That argument does not inspire trust but misgivings, raising doubts about the competence of those "experts" in risk assessment. Maybe nuclear power companies should recruit mountain guides for consulting!

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