- #36
jim hardy
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nikkkom said:Granted, *I* did not know this before Fukushima, but I don't live in Japan.
Well you made me think with that one.
I didn't know it either.
And i never considered that somebody living there might be better aware of local natural history than i.
[PLAIN said:http://carnegieendowment.org/files/fukushima.pdf][/PLAIN]
First, there appears to have been insufficient attention given by TEPCO and
NISA to historical evidence of large earthquakes and tsunamis. Best practice, as
promulgated by the IAEA, requires the collection of data on prehistorical and
historical earthquakes and tsunamis in the region of a nuclear power plant in
order to protect the plant against rare extreme seismic events that may occur
only once every ten thousand years.
36
Historical data was used in assessing plant
safety. The original design-basis tsunami for Fukushima Daiichi of 3.1 meters
was chosen because a 1960 earthquake off the coast of Chile created a tsunami
of that height on the Fukushima coast.
37
However, greater attention should have
been paid to evidence from further back in history. Over the last decade or so,
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Why Fukushima Was Preventable
Historical data was used in assessing plant
safety. The original design-basis tsunami for Fukushima Daiichi of 3.1 meters
was chosen because a 1960 earthquake off the coast of Chile created a tsunami
of that height on the Fukushima coast. 37 However, greater attention should have
been paid to evidence from further back in history. Over the last decade or so,
evidence of much larger tsunamis in and around Miyagi has emerged. Japanese
researchers have discovered layers of sediment that appear to have been depos-
ited by tsunamis and have concluded that the region had been inundated by
massive tsunamis about once every one thousand years. 38
They have attributed
the most recent of these events—in 869 AD—to a magnitude 8.3 earthquake.
More generally, given the historical record of tsunamis in Japan, TEPCO and
NISA should have been much more conservative in defining the design-basis
tsunami. For instance, one compilation of historical tsunamis in and around
Japan lists twelve events since 1498 having a maximum amplitude of more than
10 meters, six of which had a maximum amplitude of over 20 meters. 39
Of course, such “red flags” are much easier to spot with the benefit of hind-
sight than they are ahead of a disaster. The challenge of sifting through and
evaluating the stream of potentially relevant geophysical studies to extract
data important to nuclear power plant safety should not be underestimated.
Perhaps not surprisingly, there has been a fairly bitter debate within Japan
about whether academia did not provide suitable warnings or whether it did
and industry and regulators ignored them. Nonetheless, Japan has a historical
legacy of severe tsunamis; it does appear that heeding this record, especially
as it relates to the area around the plant, would have led to an upward revision
of the design basis for Fukushima Daiichi Nuclear Power Station and perhaps
consequently to infrastructural improvements to better defend the installation.
As i said, such things are debated within the bureaucracy by endless memos ( See Parkinson's "Law of Delay", chapter "The Paper Blob").
You blame the executives, i blame the bureaucrats.
I say "to-may-to", you say "to-mah-to" ? :)
old jim
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