Pennock's Fiero Forum
  Totally O/T - Archive
  Virginia Nuclear Plant Loses Power After Quake

T H I S   I S   A N   A R C H I V E D   T O P I C
  

Email This Page to Someone! | Printable Version


Virginia Nuclear Plant Loses Power After Quake by dennis_6
Started on: 08-23-2011 06:01 PM
Replies: 11
Last post by: dennis_6 on 08-25-2011 08:02 AM
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-23-2011 06:01 PM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
By TENNILLE TRACY and GARY FIELDS

A nuclear power plant in central Virginia has lost offsite power in the wake of a 5.8 earthquake centered northwest of Richmond, Va., U.S. nuclear officials said.
More

The North Anna Power Station, which has two nuclear reactors, is now using four diesel generators to maintain cooling operations. The plant automatically shut down in the wake of the earthquake.

"As far as we know, everything is safe," said Nuclear Regulatory Commission spokesman David McIntyre.

Nine nuclear plants have declared "unusual events" today, which is the lowest of four emergency situations, the NRC said.

The plants are located in Virginia, Maryland, Pennsylvania and New Jersey.
Earthquake Epicenter

View Interactive
Journal Community

The Calvert Cliffs Nuclear Power Plant in Maryland, the closest nuclear plant to Washington, D.C., remained stable at 100% of capacity, a spokesman for Constellation Energy Nuclear Group LLC said Tuesday.

Constellation declared an "unusual event" at the plant, said company spokesman Mark Sullivan.

The Calvert Cliffs plant is in Lusby, Md., along the shores of the Chesapeake Bay about 50 miles from the city limits of the nation's capital. Mr. Sullivan said that as part of normal procedure, employees were performing increased observations and instrumentation monitoring.

Mr. Sullivan said the company's nuclear plants in Scriba, N.Y., and Ontario, N.Y., were performing similar examinations although neither plant registered abnormal seismic activity.

Meanwhile, at the Indian Point nuclear power plant north of New York City, officials said some minor shaking was felt, but the facility is still online and operating at full power.

"No damage has been seen on site. Minor shaking was felt in some areas of the site. Site staff has been conducting 'walk-downs' to inspect equipment,'' said James Steets, a spokesman for Entergy Corp., which runs Indian Point.
—Devlin Barrett contributed to this article.

Write to Tennille Tracy at tennille.tracy@dowjones.com and Gary Fields at gary.fields@wsj.com

http://online.wsj.com/artic...l?mod=googlenews_wsj


-------------------------------------------------------------------------------------------------------------------------------------
Don't think its of concern right now, but remember Hurricane Irene is coming through too.

[This message has been edited by dennis_6 (edited 08-23-2011).]

IP: Logged
PFF
System Bot
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-23-2011 06:03 PM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post

dennis_6

7196 posts
Member since Aug 2001
Lake Anna Reactor Ranked 7th most At-Risk for Earthquake Damage
Posted: Mar 16, 2011 4:21 PM Updated: Mar 30, 2011 4:33 PM


The United States Nuclear Regulatory Commission has ranked the earthquake damage risk at all 104 nuclear power plants in this country. The pair operated by Dominion Power, at Lake Anna in eastern Louisa County, come in at 7th most 'at risk' on the list.

According to the Nuclear Regulatory Commission, North Anna 1 and 2 face an annual 1 in 22,727 chance of the core being damaged by an earthquake and exposing the public to radiation. The national average for U.S. nuclear plants is a 1 in 74,000 chance.

The top five most at-risk plants are all on the east coast: Indian Point, north of New York City; the Pilgrim Plant south of Boston, Limerick outside of Philadelphia, the Sequoyah plants near Chattanooga Tennessee and Beaver Valley near Pittsburgh. These five plants are at a higher statistical risk than those along fault lines in California, for example, because they were not designed for and built in presumed strong quake danger areas. Since they were constructed the federal government has revised upwards the quake risks where they are.

According to Jim Norvelle with Dominion Power, North Anna was designed to withstand a magnitude 5.9 – 6.1 earthquake.

http://www.nbc29.com/story/...or-earthquake-damage
IP: Logged
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-23-2011 06:18 PM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
2 nuclear reactors taken offline after Va. quake

(AP)

Federal officials say two nuclear reactors at the North Anna Power Station in Louisa County, Va., were automatically taken off line by safety systems around the time of the earthquake.

The Dominion-operated power plant is being run off three emergency diesel generators, which are supplying power for critical safety equipment. The NRC and Dominion are sending people to inspect the plant.

A fourth diesel generator failed, but it wasn't considered an emergency because the other generators are working, according to the Nuclear Regulatory Commission.

Dominion said it declared an alert at the North Anna facility and the reactors have been shut down safely and no major damage has been reported.

The earthquake was felt at the company's other Virginia nuclear power station, Surry Power Station in southeast Virginia, but not as strongly there. Both units at that power station continue to operate safely, Dominion said.

The quake also caused Dominion's newest non-nuclear power station, Bear Garden in Buckingham County, to shut down automatically.

NRC spokesman Roger Hannah says the agency was not immediately aware of any damage at nuclear power plants in the southeast.

Hannah said he knew of no other shut reactor but that unusual events were reported at a dozen other plant sites.

Louisa County is about 40 miles northwest of Richmond.
http://www.pressherald.com/...ap?articleID=7534152

[This message has been edited by dennis_6 (edited 08-23-2011).]

IP: Logged
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-23-2011 10:17 PM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
Either the media is contradicting itself or the nuke industry is....
-----------------------------------------------------------------------------------------------------
UPDATE: North Anna's 2 nuclear reactors shut down after quake


Following procedures, the plant was shut down.

By: Times-Dispatch Staff
Published: August 23, 2011


Dominion Virginia Power shut down its two North Anna reactors as a result of the earthquake, according to the company.

"The earthquake was felt at the North Anna Power Station and the reactor operators, following procedures, shut down the reactors," said company spokesman Jim Norvelle. "It was a manual shutdown."

The plant declared an alert, the second lowest level of emergency declaration, a commission spokesman said.

The North Anna plant lost the power from off site that runs the reactors' cooling systems, Norvelle said, but the plant's four backup diesel generators started as designed.

Officials are assessing the plant for damage, said the NRC's Joey Ledford.

"Our workers are doing a walkdown of the site as we speak," Norvelle said. Dominion Virginia Power's Surry Power Station is operating as normal, he said.

The company's second Virginia nuclear power plant, the Surry Power Station in southeast Virginia, also felt the quake, but not as strongly, Dominion Virginia Power said. Both units at Surry continue to operate.

Dominion Virginia Power's nuclear power stations were built to seismic standards for their regions, the company said.

The earthquake also caused the company's newest power station, Bear Garden in Buckingham County to shut down automatically.

Dominion Virginia Power's nuclear plants at North Anna and Surry normally carry the base load of the company's customer demand for electricity. North Anna generates 1,806 megawatts from its two units, the company says, enough electricity to power 450,000 homes.

The North Anna plant employs about 1,000 people, Norvelle said.

Almost 6,000 Rappahannock Electric Cooperative members are currently without power throughout Louisa, Spotsylvania and Hanover counties, the co-op said. "REC crews are working as quickly and safely as possible to assess damage related to the earthquake and to begin restoration work."

The co-op's phone lines were flooded after the earthquake, Rappahannock Electric said. Based in Fredericksburg, the co-op provides electric service to over 155,000 member connections in parts of 22 Virginia counties.

The largest earthquake in Virginia history was also a magnitude 5.9, which occured May 31, 1897, according to the USGS. That quake was felt from Georgia to Pennsylvania and from the Atlantic coast westward to Indiana and Kentucky. Aftershocks continued through June 6, 1897.

According to the U.S. Geological Survey, the magnitude 5.9 earthquake's epicenter was located 9 miles south-southwest of Mineral, or about 36 miles northwest of Richmond. The USGS said the earthquake occurred at 1:51:04 p.m.

An earthquake of magnitude 5.9 will produce negligible damage in buildings of good design and construction, according to the federal agency.

Damage can be light to moderate in well-built ordinary structures, the USGS said, but considerable in poorly built or badly designed structures, and some chimneys broken.

Such earthquakes are "felt by all," the USGS said. "Many [are] frightened."

Columbia Gas of Virginia reported that "at this time" there appeared to be no damage to their natural gas infrastructure as a result of the earthquake in central Virginia. Company workers went out to survey critical infrastructure around the state.

For more on the response at North Anna, see tomorrow's Richmond Times-Dispatch.
http://www2.timesdispatch.c...ut-down--ar-1257146/

[This message has been edited by dennis_6 (edited 08-23-2011).]

IP: Logged
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-24-2011 08:21 AM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
U.S. Nuclear Industry Tested by Twin Threats From Mother Nature




Aug. 24 (Bloomberg) -- U.S. nuclear plants face the first post-Fukushima test of their ability to withstand multiple natural disasters as Hurricane Irene bears down on an area shaken by a 5.8-magnitude earthquake.

The temblor yesterday knocked out power to Dominion Resources Inc.'s North Anna nuclear plant in Virginia and prompted 12 stations from North Carolina to Michigan to declare "unusual events," the lowest-level emergency designated by the U.S. Nuclear Regulatory Commission.

North Anna's twin reactors were being cooled by backup diesel generators yesterday after automatically shutting down during the earthquake, whose epicenter was less than 15 miles (24 kilometers) from the plant, about 85 miles southwest of Washington, according to the U.S. Geological Survey.

One of the plant's four diesel generators, which power the reactors' cooling systems during the blackout, stopped working as a result of a coolant leak, Roger Hannah, a spokesman for the U.S. Nuclear Regulatory Commission, said in an interview. Dominion Resources called a fifth standby generator into service to replace the broken unit, Ryan Frazier, a spokesman for the Richmond, Virginia-based company, said in an e-mail.

"It's not critical at this point," Hanah said. "They are able to operate all safety systems off the generators they have."

Read more: http://www.sfgate.com/cgi-b...ao=all#ixzz1VwrEkSTC

Rest of the article at link, this story is copyrighted.

[This message has been edited by dennis_6 (edited 08-24-2011).]

IP: Logged
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-24-2011 08:36 AM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
(Reuters) - The largest earthquake to hit the East Coast of the United States in 67 years raised concerns on Tuesday about the safety of the country's nuclear power plants.

The 5.8 magnitude quake's epicenter was just a few miles from the two-reactor North Anna nuclear power plant operated by Dominion Resources in Mineral, Virginia, 80 miles southwest of Washington.

The plant lost power and automatically halted operations after the quake. While a Dominion spokesman reported no "major" damage to the facility, three diesel generators were required to kick in and keep the reactors' radioactive cores cool. A fourth diesel unit failed.

While nuclear power plants can operate safely on back-up power, failure of generators was a key reason for the disaster at Japan's Fukushima Daiichi plant after a 9.0 magnitude quake and tsunami in March.

"Nuclear power plants lose a significant margin of safety when they're forced to rely on these emergency back-up systems," said Paul Gunter, director of reactor oversight at Beyond Nuclear, an anti-nuclear lobby group.

The Nuclear Regulatory Commission (NRC) said North Anna's shutdown was safe and posed no risk to the public. It wasn't clear when off-site power could be restored or when the 1806-megawatt plant, which remained on alert, could restart.

Dominion spokesman Jim Norvelle said the plant was designed to withstand an earthquake of up to 6.2 in magnitude.

But some experts expressed concern about the narrow margin between the design metrics and the quake's size.

"It was uncomfortably close to design basis," said Edwin Lyman of the Union of Concerned Scientists, which has pushed for stronger nuclear regulations.

"If Fukushima wasn't a wake-up call, this really needs to be to get the NRC and industry moving to do seismic reviews of all the nuclear power plants in the country."

Tuesday's quake, which was felt along the East Coast as far north as Canada, was the region's largest since a 5.9 quake hit New York State in 1944.

North Anna's reactors are among 27 east of the Rockies that the NRC highlighted during a seismic review last year as presenting a potential hazard, due to the amount of ground-shaking they were designed to withstand.

Twelve other nuclear plants along the Eastern Seaboard declared an "unusual event" following the quake, the lowest of the NRC's emergency classification ratings. North Anna's "alert" status is one step further up on a four-step U.S. emergency scale.

READY OR NOT?

Many nuclear experts say plants in the United States were designed with big margins of error built in, but last year's NRC survey found that the risks posed by earthquakes were higher than previously thought.

And Victor Gilinsky, who was an NRC commissioner at the time of the Three Mile Island nuclear disaster in Pennsylvania in 1979, said that he was concerned that safety at plants like North Anna were not being reviewed as understanding of earthquakes increases.

"It is important to review the seismic design of the plant in terms of current knowledge," he said "Instead, the NRC has been relicensing plants without any real safety review - they do not question any of the original licensing conditions, they only check to see whether the plant has a program to deal with old equipment. It's an irresponsible approach."

Still, Ronald Ballinger, an engineering professor at the Massachusetts Institute of Technology, said quakes like Tuesday's posed little danger to U.S. nuclear plants.

"The size of the vibrations from this East Coast earthquake are probably less than you would feel in a loud nightclub," Ballinger said.

Based on its 5.8 magnitude rating, the quake was almost 10,000 times weaker than Japan's quake in March and posed no tsunami risk, Ballinger said.

U.S. nuclear plants responded to Tuesday's quake as they were designed to, said Tony Pietrangelo, chief nuclear officer at the Nuclear Energy Institute trade industry group.

No other East Coast plant had operations disrupted. Entergy's Indian Point nuclear plant located north of New York City was operating normally, as was Dominion's two-unit Surry plant in Gravel, Virginia.

The last time a quake of similar magnitude hit Virginia was in 1897, the U.S. Geological Survey said. A 7.3 magnitude quake, the largest recorded in East Coast history, hit South Carolina in 1886.

Dominion is one of 11 U.S. power companies who have expressed interest in building new advanced nuclear reactors. It has proposed adding a new reactor to the North Anna plant.

(David Sheppard, Jeanine Prezioso, Roberta Rampton, Eileen Moustakis and Janet McGurty contributed reporting; Editing by David Gregorio, Martin Howell)
http://www.reuters.com/arti...dUSTRE77M8C120110824
IP: Logged
Formula88
Member
Posts: 53788
From: Raleigh NC
Registered: Jan 2001


Feedback score: (3)
Leave feedback





Total ratings: 555
Rate this member

Report this Post08-24-2011 08:38 AM Click Here to See the Profile for Formula88Send a Private Message to Formula88Direct Link to This Post
 
quote
Originally posted by dennis_6:One of the plant's four diesel generators, which power the reactors' cooling systems during the blackout, stopped working as a result of a coolant leak,


The article doesn't make it clear if that "coolant leak" is a leak of reactor coolant, or the coolant on the diesel generator.
IP: Logged
TommyRocker
Member
Posts: 2808
From: Woodstock, IL
Registered: Dec 2009


Feedback score: (1)
Leave feedback

Rate this member

Report this Post08-24-2011 08:43 AM Click Here to See the Profile for TommyRockerClick Here to Email TommyRockerSend a Private Message to TommyRockerDirect Link to This Post
 
quote
Originally posted by Formula88:


The article doesn't make it clear if that "coolant leak" is a leak of reactor coolant, or the coolant on the diesel generator.


Seems to me if would have to be an engine coolant leak. I figure that's why the engine stopped. If it had been reactor coolant you know damn well they would have been hyping it, but by mentioning coolant in a vague manner they can generate chatter and fear without actually lying.
IP: Logged
2.5
Member
Posts: 41016
From: Southern MN
Registered: May 2007


Feedback score: (1)
Leave feedback





Total ratings: 178
Rate this member

Report this Post08-24-2011 08:43 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Direct Link to This Post
I read too that the power was taken off line. (As in on purpose?)

"Federal officials say two nuclear reactors at the North Anna Power Station in Louisa, Virginia were automatically taken off line by safety systems around the time of the earthquake. The reactors are less than 20 miles from the quake's epicenter.

No damages have been reported."

--

The odd thing is a quake in Virgina, is that new?

"The U.S. Geological Survey has slightly lowered its estimate of the central Virginia earthquake felt throughout the Mid-Ohio Valley from 5.9 to 5.8.
Posted: 2:15 PM Aug 23, 2011
Reporter: WTAP News

Updated 6:39 pm

The U.S. Geological Survey has slightly lowered its estimate of the Virginia earthquake's magnitude from 5.9 to 5.8.

The USGS says more than 12 million people lived close enough to the quake's epicenter to feel shaking.

The quake was felt in 22 states.

_________________________

Updated 3:43 pm

U.S. Geological Survey geophysicist Don Blakeman says people on the East Coast should be ready for aftershocks following the 5.9 earthquake this afternoon.

A District of Columbia fire department spokesman says there are numerous injuries as a result of an earthquake that struck near the nation's capital, but so far there are no reports of serious injuries or deaths.

Thousands of people are milling about downtown after evacuating their buildings. DC Fire and EMS spokesman Pete Piringer says all city fire trucks and ambulances have been deployed. Those that aren't responding to calls are driving around and looking for structural damage, injured people and other emergencies.

A spokesman for Washington National Cathedral says at least
three of the four pinnacles on the central tower have fallen off and the central tower appears to be leaning. The Washington National Cathedral is among the tallest structures in Washington, DC.

________________________

Updated 3:32 pm

The 5.9 magnitude earthquake has rattled nerves from Georgia to New England. It forced the evacuation of the U.S. Capitol, the Pentagon and all the monuments on the National Mall in Washington.

The earthquake is also causing connection problems for cell phone customers. Verizon Wireless and AT&T say their networks were congested as the quake sent people scrambling for the phones. Sprint said some customers may be experiencing delays.

__________________________

Updated 3:07 pm

Federal officials say two nuclear reactors at the North Anna Power Station in Louisa, Virginia were automatically taken off line by safety systems around the time of the earthquake. The reactors are less than 20 miles from the quake's epicenter.

No damages have been reported.

In addition to the Mid-Ohio Valley, the earthquake was felt throughout central and northern Virginia, Washington DC, Philadelphia, New York City and as far north as Rhode Island.

________________________

Updated 2:48 pm

Rusty Roten, WV Dept of Highways District 3 Engineer, tells WTAP-TV that his department will probably be looking at some of the larger structures in the area, following this afternoon's earthquake that was felt through the Mid-Ohio Valley.

“We’ll look primarily at where the piers and the spans come together," Roten says. "Obviously, those 'bearings' are built with some seismic activity in mind, but since this is a low-quake zone, they are not as stringent as the standards in places, like California.”

Roten says that his department probably will inspect the Belpre bridge first.

No traffic interruptions are anticipated at this time.

_______________________

Updated 2:26 pm

Here's is the latest information from the U.S. Geological Survey regarding Tuesday afternoon's earthquake:

Magnitude: 5.9
Time: 1:51 pm
Location: 37.975°N, 77.969°W
Depth: 0.6 mile
Epicenter:
27 miles east of Charlottesville, Virginia
34 miles southwest of Fredericksburg, Virginia
39 miles northwest of Richmond, Virginia
50 miles north-northeast of Farmville, Virginia

___________________

WTAP News is investigating a possible earthquake that could be felt in both Ohio and West Virginia.

Viewers have called with reports of rumblings in Frontier, New Matamoras, Marietta, Belpre, Little Hocking, Reedsville, Newark and Reno, Ohio.

In West Virginia callers say they've felt the possible earthquake in Parkersburg, Vienna, Waverly, Williamstown, North End.

Stay tuned to WTAP News and WTAP.com for the latest."

http://www.wtap.com/home/he...quake_128260588.html
IP: Logged
2.5
Member
Posts: 41016
From: Southern MN
Registered: May 2007


Feedback score: (1)
Leave feedback





Total ratings: 178
Rate this member

Report this Post08-24-2011 08:53 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Direct Link to This Post
Interesting about Virginia and quakes:

“Virginia and the eastern side of the North American continent are in the middle of a tectonic plate. The North American Plate is one of the 15 or so major "chunks" of crust that float on top of the hot mantle. The plate includes both continental crust and heavier (iron- and magnesium-rich) oceanic crust.
The eastern coast of the United States marks the boundary between continental and oceanic crust, but the North American Plate includes both continental and oceanic crust. The Eastern Shore/Virginia Beach are at the edge of the continent, but are not located at the edge of the continental plate. Instead, the eastern edge of the North American Plate is in the middle of the Atlantic Ocean at the Mid-Atlantic Ridge. At that ridge, magma rises slowly and pushes Virginia (and the rest of the North American Plate) towards China, at the rate of about 2-3 centimeters/year or about 14 miles every million years.1
Virginia is located far from the edge of the North American Plate. In contrast, California/Oregon/Washington are at the edge of the North American Plate. In Southern California, the western edge of the North American Plate rubs against the eastern edge of the Pacific Plate. That boundary is marked by the San Andreas Fault and many other named/unnamed faults….”
http://www.virginiaplaces.org/geology/quake.html
IP: Logged
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-24-2011 02:22 PM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
Its the generator that is leaking coolant. The reactors and the plant as a whole are fine. As soon as they restore power this will be a non event. I am just annoyed with them saying automatic and manual shut down and all 4 generators worked as designed and then turning around and saying one of the four didn't.

From what I can tell they at least started a manual shutdown and then maybe the system automatically shut down the reactors, and one generator failed. It just seems like they scrambled to re assure the public, but someone didn't get the memo and released the actual events.
IP: Logged
PFF
System Bot
dennis_6
Member
Posts: 7196
From: between here and there
Registered: Aug 2001


Feedback score: (1)
Leave feedback





Total ratings: 115
Rate this member

Report this Post08-25-2011 08:02 AM Click Here to See the Profile for dennis_6Send a Private Message to dennis_6Direct Link to This Post
RSS Text Size Print Share This
Home / business /
North Anna restart likely to take days
By: Times-Dispatch Staff , Reed Williams
Published: August 25, 2011
» 0 Comments | Post a Comment

Tuesday's earthquake apparently shook small protective devices at the North Anna Power Station enough to shut down the plant's two nuclear reactors, officials said.

Dominion Virginia Power would not say exactly when it expects the reactors — representing nearly 13 percent of the state's electric generating capacity — will start producing power again, but it will likely take days, the company said.

Offsite power to the two nuclear reactors at the North Anna plant in Louisa County apparently was disrupted when relays on three large electrical transformers were shaken by the quake, ultimately causing the reactors to shut down automatically, utility officials said Wednesday.

"In the earthquake, the shaking actually opened the contacts" of the switches in the plant transformers, said David A. Christian, CEO of Dominion Generation. "The transformers were intact. They were not, in fact, damaged."

However, the relays' opening interrupted electrical circuits carrying power from off the site to run the two reactors' cooling systems. Loss of the power in turn tripped the reactors offline.

The relays are relatively small switches used to protect the electrical transformers from damaging overloads.

Power to the reactors was off for about 10 seconds before backup diesel generators picked up the required electrical loads to run the reactors' critical cooling systems, said Dan Stoddard, senior vice president of nuclear operations for Dominion.

Stoddard, during an interview at the North Anna plant site Wednesday, added that operators in the power station's control room were reaching for switches to manually shut down the reactors when the reactors automatically shut down.

He added that the safety of the reactors was never in jeopardy. No release of radioactive material occurred beyond the minor releases associated with normal station operations, the company said.

Several aftershocks felt in the region did not affect the station, Dominion Virginia Power said.

"Because the nuclear plants are the lowest-cost source of generation for our customers, we're making all efforts to return the units to service as soon as possible," Christian said, "yet being careful to be thorough and diligent in our post-event inspections to have absolute assurance of operational safety."

Dominion Virginia Power ended the plant's "unusual event" condition Wednesday at 1:16 p.m. after completing inspections of equipment most susceptible to seismic activity. Unusual events are the least serious of four U.S. Nuclear Regulatory Commission emergency classifications.

"We haven't found anything of significance," Christian said.

Earlier Wednesday, the company ended its alert condition, the second to least serious of the four Nuclear Regulatory Commission classifications, after starting a reactor cooling pump for each of the two North Anna nuclear units.

The 980-megawatt reactors were cooled by natural circulation and four diesel-powered emergency pumps while the reactor coolant pumps were not running.

The North Anna units were designed to withstand a magnitude-6.2 earthquake. The earthquake at 1:51 p.m. Tuesday, centered about 11 miles from the plant, had a magnitude of 5.8, according to the U.S. Geological Survey.

Tuesday's earthquake would have had to unleash at least four times more energy than it did to equal the theoretical earthquake the North Anna station was designed to withstand.

The NRC requires that nuclear-power plants be built to take into account the most severe natural phenomena historically reported in a nuclear plant's area.

Though a magnitude-5.8 quake would appear to be approaching the magnitude-6.2 quake that was the basis for the plant's design, the earthquake magnitude scale is logarithmic.

That means that an increase of just one whole unit in an earthquake's magnitude represents about 32 times more energy, explained Harley Benz, scientist in charge at the U.S. Geological Survey's National Earthquake Information Center in Golden, Colo., on Wednesday.

The difference of 0.4 of a unit in magnitude between the actual and the design-basis quake works out to four times more energy than Tuesday's earthquake released, Benz said.
pbacque@timesdispatch.com (804) 649-6813 rwilliams@timesdispatch.com (804) 649-6332
pbacque@timesdispatch.com (804) 649-6813 rwilliams@timesdispatch.com (804) 649-6332
http://www2.timesdispatch.c...ake-days-ar-1260644/
IP: Logged



All times are ET (US)

T H I S   I S   A N   A R C H I V E D   T O P I C
  

Contact Us | Back To Main Page

Advertizing on PFF | Fiero Parts Vendors
PFF Merchandise | Fiero Gallery | Ogre's Cave
Real-Time Chat | Fiero Related Auctions on eBay



Copyright (c) 1999, C. Pennock