Saturday, March 3, 2012

Best nuclear stress tests are worthless


(WSJ links may not last)

One glaring oversight, they say, is the measurement used to determine the test levels for a potentially crippling tidal wave. In at least one case, the perceived maximum level was set at 38 feet—even though Tokyo Electric Power Co.'s Fukushima Daiichi was hit by a 46-foot-high tsunami in the March earthquake and some towns saw waves of up to 132 feet.

They say the tests don't explore other types of risks, such as a deliberate attack, and don't look at multiple causes of failure, like what happened at Fukushima Daiichi, which was first hit by a major earthquake and then a tsunami.

The first paragraph is a big issue I have with Japan.  The max height at the reactor was on open ground!  This is not the height of run-up, which is what happens if you put a big seawall in front of it.  That's 132 feet!  The difference is the momentum or kinetic energy of the water.

The second point applies to all nuclear operators, who, as I have said, run a very low-class operation.  Multiple failure does not mean earthquake+tsunami!  It means things like small loss of coolant with grid power loss, and backup failure.  It means failure over 4 reactors.  All those sorts of things.  Poor operation is the reason that the probability of the next Japan is as common as the chance of a major earthquake hitting another nuclear plant.  For Toronto and New Madrid, we are talking worse than 1 in 1000, maybe as common as 1 in 500.  Enough for a nuclear disaster anywhere in the world every 10 years.

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