AP news story - Events Raise Nuke Safety Questions

[Norman Cohen <ncohen12@comcast.net>]

magnu96196@aol.com wrote:



 Events Raise Nuclear Safety Questions



 By H. JOSEF HEBERT



 WASHINGTON (AP) - Severe cracks found at one nuclear power reactor and

the

 stunning discovery of a hole that nearly breached the six-inch steel

dome of

 another facility are raising new questions about aging nuclear plants

and

 whether they are being inspected closely enough.



 The hole that went through most of the heavy reactor cover of the Davis

Besse

 power plant in Ohio and the severity of cracks found about a year

earlier at

 a reactor in South Carolina surprised federal safety regulators and the

 industry.



 Both incidents have had plant operators scurrying to look for cracking

in

 reactor control rod nozzles and, more recently, for corrosive boric

acid on

 reactor domes. It was a government-ordered inspection prompted by

cracks

 found in South Carolina in early 2001 that led to the discovery of the

David

 Besse hole this past March.



 A primary reason for the corrosion was the longtime escape through

nozzle

 cracks of borated water from inside the Davis Besse reactor vessel,

 investigators have concluded.



 So far, no one else is reporting the kind of corrosion found at the

Ohio

 plant. While 14 reactors on a close-watch list have reported at least

62

 nozzle cracks, most of them have been fixed and the rest are on a

schedule

 for repair, industry and government officials said.



 A spokesman for Duke Power says the 23 cracks found at its three Oconee

 reactors at Greenville, S.C., have been fixed.



 Still, the discoveries have prompted new questions about aging nuclear

power

 plants.



 ``It was material degradation that wasn't expected,'' acknowledges Alex

 Marion of the Nuclear Energy Institute, the industry's trade group.

Still, he

 added, the problems should not affect relicensing since the problems

are

 identified and being dealt with.



 Some industry critics disagree.



 ``The concern here is that with this inherently dangerous technology,

when it

 ages it becomes more and more unpredictable in terms of how rapidly

things

 can break, leak and crack,'' argues Paul Gunter, an anti-nuclear

activist and

 industry watchdog.



 Most reactors have a 40-year license and a growing number of utilities

are

 planning extensions.



 FirstEnergy Corp.'s 25-year-old Davis Besse reactor on the shore of

Lake Erie

 has been shut down since February, waiting for the hole in the reactor

dome

 to be patched.



 Like the reactor nozzle cracks found at the 28-year-old Duke

Power-owned

 Oconee reactor, the hole at Davis Besse was discovered before anything

 serious could go wrong, nuclear experts said.



 Still, federal safety regulators view the findings especially at Davis

Besse

 so troubling that some senior officials at the Nuclear Regulatory

Commission

 privately have characterized the cracking and corrosion as the most

 significant safety issue facing the nuclear industry since the Three

Mile

 Island accident 23 years ago.



 The steel reactor vessel, which encloses the reactor's core, has always

been

 viewed as ``a sacred component'' that will not be breached, said Brian

 Sheron, the commission's assistant director for licensing and

technology

 assessment. ``This really challenges that assumption.''



 Only a thin noncorrosive stainless steel membrane kept the hole at the

Ohio

 reactor from bursting open. And nuclear experts say if the cracks at

the

 Oconee plant had been allowed to continue, the nozzle might have

separated.



 In both cases, thousands of gallons of radioactive water would have

escaped

 from the reactor, raising the risk of the core's radioactive fuel

overheating

 and - in a worst-case scenario - possibly a meltdown and a release of

 radiation from the larger concrete containment building.



 Industry spokesmen said they are convinced backup safety systems would

have

 averted more serious problems by pumping more water into the reactor

than was

 being allowed to escape to keep the nuclear fuel safe until the reactor

could

 be shut down.



 But that's true if everything worked as planned, counters David

Lochbaum, a

 nuclear engineer and industry watchdog for the Union of Concerned

Scientists.

 If the emergency pumping systems becomes clogged with debris, if other

 equipment is damaged or a gauge misread as workers struggle to keep the

fuel

 covered with water, a more serious accident might be unavoidable, he

said.



 The Davis Besse corrosion was caused by a buildup of boric acid from

reactor

 cooling water that had been leaking from nozzle cracks since the

mid-1990s.

 The first signs of corrosion appeared four years ago when rust began

clogging

 filters, investigators said.



 Despite a 1988 NRC directive to keep reactor lids free of boron, the

layers

 of the powdery deposits hardened so much atop the dome - where access

is

 difficult because of space and radiation exposure - that workers

couldn't pry

 it loose.



 ``If this occurred in Russia we would be saying it could never happen

here,''

 former NRC Commissioner Victor Gilinsky wrote in a recent commentary on

the

 Davis Besse discovery, calling it ``a narrow escape'' from a potential

 catastrophic accident.



 But the company's engineers did not link the rust to safety-related

corrosion

 and were assured that the boron powder was harmless since they believed

heat

 from the reactor would evaporate any moisture.



 But it is now believed the water leaking from the nozzle cracks, rather

than

 evaporating, settled beneath the hardened layers of boron, providing

enough

 moisture to turn the powder back into corrosive boric acid.



 This produced ``a whole new phenomenon,'' says John Grobe, head of an

NRC

 task force investigating the incident. ``This kind of corrosion has

never

 been seen before on a reactor pressure vessel head.''



 On the Net:



 Nuclear Regulatory Commission: http://www.nrc.gov



 Nuclear Energy Institute: http://www.nei.org



 Union of Concerned Scientists: http://www.ucsusa.org





Coalition for Peace and Justice and the UNPLUG Salem Campaign; 321 Barr

Ave., Linwood, NJ 08221; 609-601-8583 or 609-601-8537; 

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