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Re: DB liner thinner than first thought - and cracking
All the more credit to the engineers to conservatively designed the
reactor to begin with and did NOT decide to save a great deal of money
by designing it 1/2 as thick - which quite obviously (through the magic
of hindsight) would have been thick enough.
Good work guys - keep it up!
Norman Cohen wrote:
>
> "Dr. Bill Corcoran at NSRC" wrote:
>
> > __________________________________________________________________________________________________________________ Nuclear
> > plant's liner thinner than first thought
> >
> > The Associated Press
> > 9/11/02 3:17 AM
> >
> > OAK HARBOR, Ohio (AP) -- The stainless-steel liner under the lid of
> > the now-closed Davis-Besse nuclear reactor was thinner than officials
> > originally believed and had begun to crack in several places, a
> > laboratory analysis shows.
> >
> > The strength of the liner was critical because when corrosion created
> > a large hole in the reactor's lid, the liner became the only barrier
> > between the reactor's high-pressure coolant and the building that
> > houses the reactor, The (Cleveland) Plain Dealer reported Wednesday.
> >
> > The liner was supposedly three-eighths of an inch thick. But testing
> > determined that the liner was significantly thinner in places -- in
> > one location nearly 50 percent thinner -- than plant owner FirstEnergy
> > Corp. believed.
> >
> > Officials of Davis-Besse and the Nuclear Regulatory Commission don't
> > know how or when the cracks formed, or even how deep they go, and said
> > Tuesday that they are still reviewing the findings.
> >
> > But the presence of cracks raise questions about whether the barrier
> > was as strong as FirstEnergy Corp. has said and how much longer it
> > would have been able to withstand the reactor's operating pressures.
> >
> > The answers to those questions will affect the outcome of NRC and
> > Davis-Besse studies to determine how close the Toledo-area plant came
> > to a major nuclear accident. That finding, in turn, will dictate what
> > penalties and continuing scrutiny FirstEnergy faces from the NRC.
> >
> > "We want to know more, obviously," said William Beecher, an NRC
> > spokesman.
> >
> > "It's important to know what happened . . . every detail," agreed
> > FirstEnergy spokesman Todd Schneider.
> >
> > Davis-Besse officials learned of the cracks Monday night, Schneider
> > said.
> >
> > The reactor has been idle since February, when the plant shut down so
> > workers could inspect for cracks in the 69 nozzles that penetrate its
> > massive steel lid. Nozzle cracking has been a recognized issue
> > industrywide for years in older reactors. The cracks were thought to
> > be relatively benign, but the NRC became alarmed when more extensive,
> > possibly dangerous cracks were found at a South Carolina reactor in
> > 2001.
> >
> > At Davis-Besse, workers found not only serious cracking, but also the
> > 6-by-8-inch hole formed by the reactor's corrosive coolant leaking
> > from the cracks and pooling undetected on the lid for years.
> >
> > FirstEnergy has used the liner's strength as part of its argument to
> > the NRC that Davis-Besse wasn't close to an accident, and thus it
> > doesn't deserve a harsh punishment. Although the company will have to
> > revise its safety calculations based on the new crack findings, its
> > argument still holds, Schneider said.
> >
> > "We have to remember that the liner held normal operating pressure and
> > that the plant shut down safely," he said.
> >
> > Copyright 2002 cleveland.com. All Rights Reserved.
> >
> >
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> >
> >
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>
> "Dr. Bill Corcoran at NSRC" wrote:
>
> > Colleague, Please be so kind as to scroll down for today's update. I
> > have been getting off-line messages from some of you and will be
> > getting to them AWLP. Thanks for your patience. Best Regards, Bill
> > Corcoran W. R. Corcoran, Ph.D., P.E.
> > Nuclear Safety Review Concepts
> > 21 Broadleaf Circle
> > Windsor, CT 06095-1634
> > 860-285-8779 Fax: 702-993-2408
> > Mission: Saving lives, pain, assets, and careers through thoughtful
> > inquiry. Check out our e-groups at
> > http://groups.yahoo.com/group/Root_Cause_State_of_the_Practice/
> > where you will find all back issues of "The Firebird Forum" and at
> > http://groups.yahoo.com/group/DBRVH_LTBL/
> > where you will find a dialogue on the Davis-Besse near miss LOCA.,
> > including photos, polls, files, tables, and links. For a complimentary
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> > http://pages.prodigy.net/corcoran.nsrc/index.html
> > ___________________________________________________________________________________________________________________
> > Nuclear plant's liner thinner than first thought
> >
> > The Associated Press
> > 9/11/02 3:17 AM
> >
> > OAK HARBOR, Ohio (AP) -- The stainless-steel liner under the lid of
> > the now-closed Davis-Besse nuclear reactor was thinner than officials
> > originally believed and had begun to crack in several places, a
> > laboratory analysis shows.
> >
> > The strength of the liner was critical because when corrosion created
> > a large hole in the reactor's lid, the liner became the only barrier
> > between the reactor's high-pressure coolant and the building that
> > houses the reactor, The (Cleveland) Plain Dealer reported Wednesday.
> >
> > The liner was supposedly three-eighths of an inch thick. But testing
> > determined that the liner was significantly thinner in places -- in
> > one location nearly 50 percent thinner -- than plant owner FirstEnergy
> > Corp. believed.
> >
> > Officials of Davis-Besse and the Nuclear Regulatory Commission don't
> > know how or when the cracks formed, or even how deep they go, and said
> > Tuesday that they are still reviewing the findings.
> >
> > But the presence of cracks raise questions about whether the barrier
> > was as strong as FirstEnergy Corp. has said and how much longer it
> > would have been able to withstand the reactor's operating pressures.
> >
> > The answers to those questions will affect the outcome of NRC and
> > Davis-Besse studies to determine how close the Toledo-area plant came
> > to a major nuclear accident. That finding, in turn, will dictate what
> > penalties and continuing scrutiny FirstEnergy faces from the NRC.
> >
> > "We want to know more, obviously," said William Beecher, an NRC
> > spokesman.
> >
> > "It's important to know what happened . . . every detail," agreed
> > FirstEnergy spokesman Todd Schneider.
> >
> > Davis-Besse officials learned of the cracks Monday night, Schneider
> > said.
> >
> > The reactor has been idle since February, when the plant shut down so
> > workers could inspect for cracks in the 69 nozzles that penetrate its
> > massive steel lid. Nozzle cracking has been a recognized issue
> > industrywide for years in older reactors. The cracks were thought to
> > be relatively benign, but the NRC became alarmed when more extensive,
> > possibly dangerous cracks were found at a South Carolina reactor in
> > 2001.
> >
> > At Davis-Besse, workers found not only serious cracking, but also the
> > 6-by-8-inch hole formed by the reactor's corrosive coolant leaking
> > from the cracks and pooling undetected on the lid for years.
> >
> > FirstEnergy has used the liner's strength as part of its argument to
> > the NRC that Davis-Besse wasn't close to an accident, and thus it
> > doesn't deserve a harsh punishment. Although the company will have to
> > revise its safety calculations based on the new crack findings, its
> > argument still holds, Schneider said.
> >
> > "We have to remember that the liner held normal operating pressure and
> > that the plant shut down safely," he said.
> >
> > Copyright 2002 cleveland.com. All Rights Reserved.
> >
> >
> > Yahoo! Groups Sponsor
> ADVERTISEMENT
>
> >
> > To unsubscribe from this group, send an email to:
> > DBRVH_LTBL-unsubscribe@yahoogroups.com
> >
> >
> >
> > Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
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