Wind-driven aluminum siding shuts down Calvert Cliffs reactor
As reported by CNN: "A nuclear power reactor automatically went offline late Saturday in Calvert Cliffs after its main transformer was hit by a piece of aluminum siding that Hurricane Irene had peeled off a building, said Mark Sullivan, spokesman for the Constellation Energy Nuclear Group said. All employees were safe."
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Robert Alvarez of the Institute for Policy Studies shared the following this morning:
"Keep in mind that when these large reactors scram, it's like a jumbo jet making a quick forced landing. The sudden insertion of control rods creates unexpected stress on the reactor. This is why when a reactor is normally shut-down for refueling, it is done gradually. If a reactor experiences several scrams during a year, this should raise a red nuclear safety flag.
While working in DOE, I was involved in energy emergency planning, and electricity blackouts, NRC staff were definitely concerned about the safety of increased scrams caused by forced power outages.
BTW, scram is an acronym going back to the experimental 'pile' at the University of Chicago in the early 1940's. It stands for safety control [rod] axe man. According to Norman Hillbury who worked on the U. of Chicago pile:
'When I showed up on the balcony on that December 2, 1942 afternoon, I was ushered to the balcony rail, handed a well sharpened fireman's ax and told, 'if the safety rods fail to operate, cut that manila rope.' The safety rods, needless to say, worked, the rope was not cut... I don't believe I have ever felt quite as foolish as I did then. ...I did not get the SCRAM [Safety Control Rod Axe Man] story until many years after the fact. Then one day one of my fellows who had been on Zinn's construction crew called me Mr. Scram. I asked him, 'How come?'
Best,
Bob"
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A follow-up NRC Daily Event Report filed on August 29 by Constellation Energy to the NRC identified that the wind blown debris crashed into an electrical transformer at the Calvert Cliffs nuclear station causing an electrical short and "An unanticipated explosion within the Protected Area resulting in visible damage to permanent structures or equipment." One has to wonder what an "anticipated" explosion might look like?
The same report further identifies: "At 2400, 8/27/2011, numerous alarms on the 1A DG [Diesel Generator] started to be received. These were investigated and it was found that water was intruding down the DG exhaust piping resulting in a DC ground. Based on these indications the 1A DG was declared inoperable and appropriate technical specifications implemented."
Another Daily Event Report issued the same day identified that Hurricane Irene simulataneously disabled the emergency public notification sirens for two counties in the reactor's emergency planning zone due to loss of power and further revealing that the power company has bothered to provide a battery back-up power to its public emergency notification sirens. So much for defense in depth.