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NRC Report: Transformer “explosion” near turbine building at Maryland nuke plant

Published: August 29th, 2011 at 12:06 pm ET
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Event Notification Report for August 29, 2011, U.S. Nuclear Regulatory Commission:

Facility: CALVERT CLIFFS
Region: 1 State: MD
Event Date: 08/27/2011
Event Time: 23:02 [EDT]
Last Update Date: 08/28/2011
Emergency Class: UNUSUAL EVENT
10 CFR Section:
50.72(a) (1) (i) – EMERGENCY DECLARED
50.72(b)(2)(iv)(B) – RPS ACTUATION – CRITICAL
[...]
Event Text
UNUSUAL EVENT – TRANSFORMER EXPLOSION NEAR TURBINE BUILDING

“At 2248 on 8/27/2011, the Unit 1 Reactor experienced an automatic trip due to loss of load. This trip occurred due to a phase to phase short on the main generator output step-up transformer that resulted from a large section of turbine building siding breaking loose in high winds from Hurricane Irene and impacting the transformer. This impact resulted in an explosion (briefly until the trip removed power from the impact area) which met emergency action level declaration criteria A.U.6.2.2, ‘Unanticipated explosion within Protected Area resulting in visible damage to permanent structures or equipment.’ The Unusual Event was declared at 2302, 8/27/2011. Follow-up investigation determined no fire resulted from the explosion.

“Following the trip, Emergency Procedure, EOP-0, ‘Post Trip Immediate Actions’ was implemented. All safety functions were met during EOP-0 indicating an uncomplicated reactor trip response, allowing transition to EOP-1, ‘Reactor Trip,’ at 2300, 8/27/2011. During implementation of EOP-1, it was noted that #14 Containment Air Cooler had stopped running, as had #21 and #24 Containment Air Coolers on Unit 2. This was investigated and it was determined they had stopped running due to an instantaneous voltage drop that had occurred on the site distribution system during the phase to phase short event. This short duration voltage drop caused the Containment Air Coolers’ controller to drop out and secure them. They were restarted without issue.

“At 2400, 8/27/2011, numerous alarms on the 1A DG 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.”

[...]

Published: August 29th, 2011 at 12:06 pm ET
By
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15 comments

Related Posts

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  3. Congressman: Emergency diesel generator was inoperable due to flooding at Maryland nuke plant where transformer exploded during hurricane August 31, 2011
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August 29th, 2011 | Tags: | Category: East Coast, US
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15 comments to NRC Report: Transformer “explosion” near turbine building at Maryland nuke plant

  • Chatham Painter
    August 29, 2011 at 1:19 pm

    I like the concept of a ‘brief explosion’.


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  • xdrfox
    August 29, 2011 at 2:21 pm

    By the time it got there it had “HIGH WINDS” ???
    40 MPH Gust ??, How safe are these Buildings ???


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  • americancommntr
    August 29, 2011 at 2:29 pm

    If a coal burning plant really screws up the worst that can happen is an expensive piece of equipment is destroyed and some power goes out. If a nuclear plant screws up four states become uninhabitable, a million people get cancer, generational genetic damage is done, and the farmland and surface and ground water are rendered unusable for centuries. Yeah, nuclear power sure is safe. Odds versus stakes, the stakes are listed above, the odds are an accident will happen in the US like Chernobyl or like Fukushima.


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  • americancommntr
    August 29, 2011 at 2:33 pm

    Can you freaking imagine what would happen if an 1811 series of earthquakes took place again in the Mississippi Valley?

    THIS NATION WOULD BE DESTROYED FROM THE MELTED OUT NUCLEAR PLANT CORES AND BURNING SPENT FUEL POOLS.


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  • Sickputer
    August 29, 2011 at 3:18 pm

    >The new PM of Japan is Pro-Nuke.
    How in the world did that happen ???

    I hope you are being facetious…*;-)

    They have to have somebody arrange to pay for the Tepco executives mid-year excursion to Sao Paulo!

    They will need to stay healthy down there while this all gets sorted out. >;->


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    • Misitu
      August 29, 2011 at 5:18 pm

      Sickputer said, “They have to have somebody arrange to pay for the Tepco executives mid-year excursion to Sao Paulo! ”

      yes, but only one way tickets this year


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  • alasanon
    August 29, 2011 at 5:31 pm

    C’mon, Calvert Cliffs!!

    The odds are not good with so many plants…

    Ask Japan about that!

    If you could see what downed large trees from the hurricane did to houses and cars here in the region…It’s amazing there is no TMI pending.


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