Power Lines to Nuclear Plants Knocked Out by Tornado Outbreak in Virginia and Alabama

Tornado Cuts Power to Surry Nuclear Power Plant in Virginia

April 18, 2011

ViriginaBusiness.com - The weekend storm that spawned deadly tornados over some parts of North Carolina and Virginia knocked out electrical power to two nuclear units at Dominion Virginia Power’s Surry Power Station. The U.S. Nuclear Regulatory Commission said Monday that it’s monitoring the situation after Surry’s offsite power was knocked out early Saturday evening by a tornado.

According to Dominion Virginia Power, an apparent tornado touched down on the switchyard supporting the power station near the facility’s access road, cutting off the electrical feed from the grid to the station. The plant is located about 17 miles northwest of Newport News.

The NCR reported that Surry’s two units automatically shut down after losing power, and four of the plant’s diesel generators started to power the units’ emergency loads. Dominion notified the NRC of the situation soon after it happened and declared an “unusual event,” the lowest of the four NRC emergency classification levels, around 7 p.m.

Roger Hannah, a spokesman for the NRC in Atlanta, said the agency sent its two resident inspectors to Surry, and also is following the situation through an incident response center in Atlanta.

“In a situation like this, we have a handful of technical experts on standby in Atlanta, so the resident inspectors can call and ask questions.” He said the NRC assigns resident inspectors to every U.S. nuclear plant, and that the typical number, as in the case with Surry, is two. Monitoring will continue, Hannah added, until “they restore the offsite power, and I think they are well on the way to doing that … When they say they are no longer in the unusual event, we’ll stop the monitoring, although we may do a follow up inspection.”

By early afternoon today, Dominion Virginia Power said crews had restored power, although the NRC was reporting that power had been partially restored.

Dominion said in a press release that the tornado did not strike the two nuclear units, which are designed to withstand natural events such as tornados, hurricanes and earthquakes.

The reactors are housed inside steel reinforced concrete containment buildings. In addition, the company reported no release of radioactive material beyond minor releases associated with normal station operations. Dominion said these minor releases are below federally approved operating limits, and pose no threat to station workers or the public.

There were no injuries at the site. In addition to the NRC, Dominion notified state and local officials about the power outage.

Asked about the frequency of tornados knocking out power to nuclear plants in this country, Hannah said it’s not unheard of during bad storms.

“I don’t know of any that have completely lost offsite power, but it’s not unusual with bad storms to lose power. It’s unusual to have a switchyard problem, where you lose all power, but it’s not unheard of.”

Tornado Outbreak Knocks Out Offsite Power to Browns Ferry Nuclear Plant in Alabama, Triggering Automatic Shutdown of All Three Reactors and Startup of Backup Diesel Generators to Supply Power to the Plant's Safety System

Dozens of tornadoes spawned by a powerful storm system wiped out neighborhoods across a wide swath of the South, killing at least 209 people in the deadliest outbreak in nearly 40 years, and officials said Thursday they expected the death toll to rise. "Including yesterday's storm, there have been a whopping 800 reports of tornadoes in April, easily surpassing April 2003's all-time record of 543 twisters. We rounded up videos of some of this month's twisters here. And check out the New York Times' map of where tornadoes hit here" [The Lookout, Watch Tuscaloosa’s terrifying tornado, April 28, 2011].

"The Browns Ferry nuclear power plant about 30 miles west of Huntsville lost offsite power. The Tennessee Valley Authority-owned plant had to use seven diesel generators to power the plant's three units. The safety systems operated as needed, and the emergency event was classified as the lowest of four levels, the Nuclear Regulatory Commission said" [Dozens of tornadoes kill 209 in 6 Southern states, Associated Press, April 28, 2011].

April 28, 2011

Russ' Place - All 3 Browns Ferry units (identical to Fukushima’s) are knocked off-line.

I recently wrote about my on-site experience with the Browns Ferry nuclear power plant. This plant is virtually a twin of Japan’s Fukushima power plant. Both use the General Electric Mark 1 Boiling Water Reactor (BWR) and were built between 1965 and 1974.

Yesterday, giant storms roared through the Birmingham, Alabama area and knocked out high voltage power lines that feed the Browns Ferry plant. This triggered shutdowns of all 3 reactors and probably start-up of the plant’s Diesel generators, to cool the reactors’ cores.

In a press release last night, TVA stated:

“The three units at the Browns Ferry Nuclear Plant in northern Alabama automatically shutdown as a result of transmission line damage from the storm. The plant is safely shutdown and is using a combination of offsite transmission lines and on-site diesel generators to provide power to the plant. At 4:36 p.m. (central time) Browns Ferry declared an “Unusual Event,” due to the automatic shutdown of the plant. An Unusual Event is the lowest level of emergency at a U.S. nuclear plant. I’d like to emphasize that the nuclear plant is performing as designed… and all systems are operating safely.“

TVA's Browns Ferry Nuclear Plant is located near near Athens, Ala. (AP Photo/Jay Reeves)

Storms Knock Out TVA Nuclear Units, Power Lines

April 27, 2011

Reuters - Severe storms and tornadoes moving through the Southeast dealt a severe blow to the Tennessee Valley Authority on Wednesday, causing three nuclear reactors in Alabama to shut and knocking out 11 high-voltage power lines, the utility and regulators said.

All three units at TVA's 3,274-megawatt Browns Ferry nuclear plant in Alabama tripped about 5:30 EDT (2230 GMT) after losing outside power to the plant, a spokesman for the U.S. Nuclear Regulatory Agency said.

A TVA spokeswoman said the plant's output had reduced power earlier due to transmission line damage from a line of severe storms that spawned a number of tornadoes as it moved through Mississippi, Alabama, Kentucky and Tennessee. The NRC spokesman said early information indicated the units shut normally and the plant's diesel generators started up to supply power for the plant's safety system.

The government-owned corporation said crews were working to restore service, but more severe weather was forecast, TVA said in a release.

Most of the damage so far has occurred in the western part of TVA's service territory in Mississippi, Alabama and western Tennessee and Kentucky.

Cullman Electric Cooperative in Cullman, Alabama, is the only power company directly affected by TVA's transmission outage, TVA said in a statement.

Rainfall amounts between four and seven inches have fallen since Tuesday in the area. Eight of the nine dams on the Tennessee River were generating at full power to move water through the river system to help control flooding, TVA said.

Details of the transmission outages and co-op power outages were immediately available.

TVA Loses All Power Transmission Lines in Alabama and Mississippi, Browns Ferry Nuclear Plant Forced into Emergency Shutdown

April 28, 2011

Chattanooga Times Free Press - Wednesday’s storms took out all of TVA’s electric power transmission lines in Mississippi and North Alabama, and forced Browns Ferry Nuclear Plant unto diesel backup power and into emergency and automatic cold shutdown.

Bill McCollum, the chief operating officer of Tennessee Valley Authority, said it may be weeks before power can be restored to all of the 300,000 customers whose power is supplied by the federal utility.

“With the level of damage we have, it will be — we hope it will be days until we get most of the customers back on, but it will be weeks before we’ve fully repaired all of the damage,” he said.

McCollum said the reactors, now being cooled by backup diesel power, are safe.

He said the spent fuel pools also are being cooled by backup diesel power and are safe.

The transmission lines are the monster power lines that carry electricity from TVA power plants to power distributors such as EPB and Huntsville Utilities. Now those utilities, along with a number of large industries that are wired directly to TVA transmission lines, will not have power until the lines are repaired, McCollum said.

The loss of those transmission lines also caused Browns Ferry Nuclear Plant to lose power.

When the plant generates power, it uses some of that power and the excess is sent out on the transmission lines. When those transmission lines can’t take power, it causes the reactors to trip, according to TVA officials.