Hole Found in Containment Liner at Nuclear Plant, Board in Cement Blamed

Below are news reports on a hole found in the steel liner of a reactor containment wall; six days after the story was reported, the hole was attributed to a board embedded in the concrete containment wall. 

 

Beaver County Times

By Bill Vidonic, Times Staff

Friday, April 24, 2009 

SHIPPINGPORT — An inspection Thursday revealed corrosion in the steel lining of the nuclear reactor containment building of Beaver Valley Nuclear Power Station’s Unit 1, according to FirstEnergy Corp.
No radiation was released from the building, and there was “no impact to the public health or safety of any employees,” FirstEnergy spokesman Todd Schneider said Friday evening.
The Unit 1 reactor had been shut down since Monday for scheduled refueling and maintenance. As part of that work, Schneider said, the containment building that surrounds the reactor underwent a standard inspection.
The containment building has concrete walls that are 4 feet thick, Schneider said, and there’s a 3/8-inch-thick steel lining on top of that concrete in the building’s interior.
The steel is coated with what Schneider described as “nuclear-grade paint.” An inspection showed a blister in some of that coating. The blister wasn’t cracked, Schneider said.
Once the coating was cleaned, Schneider added, workers found that the steel underneath it had corroded through to the concrete wall. The affected area of the steel is in the shape of a rectangle, Schneider said, about one inch long by about 3/8-inch high. That’s just under the size of a standard paper clip.

Schneider said the concrete beneath the steel lining was not cracked or damaged by the steel corrosion, so there was no danger of a radiation leak.
As required by federal regulations, the Nuclear Regulatory Commission was notified about the blister, Schneider said, though the discovery was not considered an emergency.
Wes Hill, director of Beaver County Emergency Services, said Friday evening that his department was not notified of the discovery.

Schneider said the blisters have been discovered at other nuclear plants in the past, so there’s an established procedure to follow in making repairs.
The corroded steel will be removed, Schneider said, and another piece of steel will be welded into place. The removed steel will be examined to try to determine what caused the damage.
The affected area was last inspected in 2007 during another maintenance outage, Schneider said, and no problems were found then, so the corrosion occurred within the last couple of years.
Schneider would not say how long the reactor will remain off line for its scheduled maintenance, but said Thursday’s discovery wouldn’t delay the reactor restart; the repair to the steel will proceed during the refueling and maintenance work.
Once repairs are made, Schneider said, tests will be conducted “to ensure the safe operation of the plant” before the reactor is restarted.
The reactor was first brought online in 1976.
The Shippingport nuclear power station’s second reactor, Unit 2, remained online and operating normally Friday, Schneider said. That unit, first online in 1987, was last inspected in spring 2008, he added; no problems were detected in that building at that time.
An NRC spokesman could not be reached for comment Friday night.

Bill Vidonic can be reached online at bvidonic@timesonline.com.

 

 

By Bob Bauder, Times Staff

Published: Thursday, April 30, 2009 1:21 AM EDT

SHIPPINGPORT — FirstEnergy Corp. believes it has determined what caused 

the hole discovered last week in the steel lining of a reactor containment building 

at the Beaver Valley Nuclear Power Station.

 

The hole, measuring about 1 inch by 3/8 inch, in the Unit 1 reactor containment 

building was discovered Thursday during a routine inspection. The reactor had 

been shut down earlier last week as part of a scheduled refueling and maintenance

outage.

 

The containment building is built of 4-foot-thick concrete walls with a 3/8-inch-thick 

steel liner underneath the concrete.

 

Company spokesman Todd Schneider said workers enlarged the hole and found a 

2-by-4-inch board embedded in the concrete, touching the steel liner. FirstEnergy

believes moisture from the board, which has been there since at least 1976 when 

the reactor first went online, caused the steel to corrode.

 

Schneider said no one knows exactly how the board ended up in the concrete.

 

The board has been removed, and the concrete has been replaced. Workers will 

weld  a steel patch to cover the hole. Schneider said the area would be 

pressure-tested to ensure an airtight seal.

 

The repair also must pass Nuclear Regulatory Commission standards.

 

Pieces of the board and corroded liner have been sent for laboratory testing as 

part of an investigation into the cause, Schneider said.

 

He said the incident would not affect the continuing outage.

 

 

 

Hole found in containment liner at nuclear plant

Beaver Valley Unit 1 already shut down

Saturday, April 25, 2009

By Don Hopey, Pittsburgh Post-Gazette

A small rectangular hole was discovered in the steel containment liner plate at FirstEnergy Corp.'s Beaver Valley Unit 1 nuclear reactor in Shippingport, Beaver County, which had been shut down Monday for refueling and routine inspection and maintenance.

According to the U.S. Nuclear Regulatory Commission, the non-emergency "event" was reported at 10:15 a.m. Thursday after company inspectors found a small patch of blistered paint and protruding rust on the wall of the steel containment liner in the circular domed reactor containment structure.

"They found a small section of corrosion," said Neil Sheehan, a NRC spokesman. "The steel liner is a vapor barrier that would only come into use if there is an accident, but is one of the barriers that needs to be vigorously maintained."

The 3/8-inch thick steel liner is a "principle safety barrier," according to NRC, and is located along the inside of the three-foot-thick, steel-reinforced, concrete containment structure in which the nuclear reactor is located.

Todd Schneider, a spokesman for the Akron, Ohio-based energy company, said its inspectors noticed the blistered paint and removed the corroded material to find a hole approximately one inch long and 3/8-inch wide that penetrated the steel barrier.

"It appears as though the rust corroded the steel from the inside out," said Mr. Schneider, adding that the corroded area will be cut out and a steel patch welded in place.

The cause of the corrosion is under investigation. Mr. Schneider said other steel containment liners at other reactors have experienced corrosion but not to the degree discovered at Beaver Valley Unit 1.

He said he expects the repairs will be completed within the normal reactor refueling period and will not delay its restart. He declined to say how long the refueling work will take for "competitive reasons."

FirstEnergy's Unit 1 and Unit 2 nuclear reactors at Beaver Valley produce about 1,779 megawatts of power. The company has applied to extend the permit for its Unit 1 reactor until 2036 and its Unit 2 reactor until 2047. A decision on the permits is expected later this year.

Don Hopey can be reached at dhopey@post-gazette.com or 412-263-1983.

First published on April 25, 2009 at 12:16 am

 

 

 

By Bill Vidonic, Times Staff

Saturday, April 25, 2009 

SHIPPINGPORT - Thursday's discovery of a small hole in the steel  

lining of the reactor containment building of Beaver Valley Nuclear  

Power Station's Unit 1 wasn't the first time a breach has been found  

there, a Nuclear Regulatory Commission spokesman said Saturday.

 

Before Thursday's discovery, no radiation was released from the  

building, and there was "no impact to the public health or safety of  

any employees," FirstEnergy spokesman Todd Schneider said Friday  

evening.

 

NRC spokesman Neil Sheehan said that in 2006, corrosion was found in  

the lining of the same containment building when the reactor was shut  

down so that FirstEnergy could replace the reactor lid and three steam  

generators.

 

The Unit 1 reactor has been shut down since Monday for scheduled  

refueling and maintenance. As part of that routine work, the  

containment building around the reactor was inspected, Schneider said.

 

The containment building has concrete walls that are 4 feet thick,  

Schneider said, and there's a 3/8-inch-thick steel lining on top of  

that concrete in the building's interior.

 

Sheehan said that lining is a vapor barrier and would only be used to  

contain gases and radiation if there's a serious problem with the  

nuclear reactor.

 

The steel is coated with what Schneider described as "nuclear-grade  

paint." The inspection showed a blister in some of that coating.

 

Once the coating was cleaned, Schneider added, workers found that the  

steel underneath had corroded through to the concrete wall. The  

affected area of the steel is a rectangle, Schneider said, about 1  

inch long by about 3/8-inch high. That's just under the size of a  

standard paper clip.

 

Schneider said the concrete beneath the steel lining was not cracked  

or damaged by the steel corrosion, and there was no danger of a  

radiation leak.

 

"There's certainly no immediate cause for concern," Sheehan said  

Saturday. "It's a very small area on a very large liner (measuring  

thousands of square feet). The risk of an accident is small, and the  

(affected) area is small, but we take any sort of problem involving a  

barrier between radioactivity and the environment very seriously."

 

Sheehan said the NRC also wants to know what caused the corrosion, and  

whether any other parts of the liner have been affected, as  

inspections continue.

 

The containment building is built to hold in gases in the event of a  

nuclear accident.

 

As required by federal regulations, the NRC was notified about the  

blister, Schneider said, though the discovery was not considered an  

emergency.

 

Wes Hill, director of Beaver County Emergency Services, said Friday  

evening that his department had not been notified of the discovery.

 

The affected area was last inspected in 2007 during another  

maintenance outage, Schneider said, and no problems were found then,  

so the corrosion occurred within the last couple of years.

 

Sheehan said that in 2006, inspectors found a small area of corrosion  

that was repaired. Then, Sheehan said, it was ruled that moisture  

trapped between the concrete and the liner caused the corrosion.

 

Schneider said Saturday that in the 2006 discovery, the corrosion  

didn't eat all the way through the barrier.

 

"We're always interested in trends," Sheehan said of Thursday's  

discovery. "If this says something about any systemic corrosion, we  

would want to know about that."

 

The corroded steel will be removed, Schneider said, and another piece  

of steel will be welded into place. The removed steel will be examined  

to try to determine what caused the damage.

 

The Cleveland Plain Dealer reported Friday that a coolant leak in the  

lid of FirstEnergy's Davis-Besse nuclear power plant near Toledo was  

undiscovered for several years. That allowed corrosion, which was  

accelerated by boric acid, to eat through a 6-inch-thick carbon steel  

lid.

 

The acidic vapors also caused corrosion problems in gear and paint  

throughout the containment building at Davis-Besse.

 

Schneider said that the Shippingport corrosion was not caused by boric  

acid, which is added to reactor coolant.

 

Schneider would not say how long the reactor will remain offline for  

its scheduled maintenance, but said Thursday's discovery won't delay  

the reactor restart; the repair to the steel will proceed during the  

refueling and maintenance work.

 

Once repairs are made, Schneider said, tests will be conducted "to  

ensure the safe operation of the plant" before the reactor is restarted.

 

Sheehan said FirstEnergy "appears to be responding appropriately" to  

Thursday's discovery.

 

The 911-megawatt reactor was first brought online in 1976.

 

The Shippingport nuclear power station's second reactor, Unit 2,  

remained online and operating normally Friday, Schneider said. That  

unit, first online in 1987, was last inspected in spring 2008, he  

added. No problems were detected in that building at that time.

 

Bill Vidonic can be reached online at bvidonic@timesonline.com.=