This is a mirror of the original report posted at ANS Nuclear Cafe It relies on information from NEI and the NRC. Set your web browser to access the ANS Nuclear Cafe throughout the weekend for updates.
When hurricanes occur, electric utilities operating nuclear energy facilities take specific actions mandated by U.S. Nuclear Regulatory Commission guidelines and the plants’ emergency preparedness plan. These include:
- Plant personnel monitor storm conditions, paying close attention to the path of a storm and wind speeds at the site.
- Personnel inspect the entire facility and secure or move any equipment that could possibly become airborne due to high winds.
- Each plant site has numerous emergency backup diesel generators that are tested and ready to provide electricity for critical operations in the event of a loss of off-site electricity supply. Diesel fuel tanks are checked and topped off to ensure there is a minimum of seven days of fuel to power backup generators.
- As a precaution, a reactor will be shut down at least two hours before the onset of hurricane-force winds at the site, typically between 70 and 75 miles per hour.
- Twelve hours before Hurricane Irene approaches nuclear energy facilities on the East Coast, plant operates at each site will provide status updates to the Nuclear Regulatory Commission.
If there is a loss of off-site power, reactors automatically shut down as a precaution and the emergency backup diesel generators begin operating to provide electrical power to plant safety systems. Plant operators also may manually shut down the reactor as a precaution even if off-site power is still available.
Nuclear power plants are the most robust facilities in the U.S. infrastructure, with reactor containment structures composed of steel-reinforced concrete that have proven their ability to withstand extreme natural events. In addition, nuclear plant operators are trained and tested one out of every six weeks to safely manage extreme events such as hurricanes. Plant operators also have multi-day staffing plans, and resources, to ensure that personnel are on-site and prepared to respond to situations that may arise as a result of the storm.
NRC notes reactor preparation
The NRC’s Roger Hannah told wire services Aug 26 that typically utilities begin shutting down reactors 12 hours before winds reach speeds of 74 miles an hour. He pointed out there is a big difference between a storm surge and a tsunami.
In Washington, DC, the NRC is mobilizing its emergency operations center to keep track of conditions at all the nuclear reactors up and down the U.S. eastern seaboard. The center stays in close touch with resident inspectors at the plants. If land lines go out, they switch to satellite phones to stay in touch. Once the storm has pass, the NRC works with FEMA to assess any damage.
- Follow the NRC on Twitter @NRCgov or the agency’s blog at http://public-blog.nrc-gateway.gov/ for agency public information updates.
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- Follow NEI on Twitter @N_E_I
Roundup of site specific news
While preparations are generally the same at all reactors when faced with an imminent hurricane, here are some highlights from the different sites.
* At Dominion’s Millstone nuclear plant in Connecticut, which is located on Long Island sound near Waterford, CT, workers are preparing defenses against an expected storm surge. Staffing plans for storm emergencies are being put into effect. Outside maintenance project are being postponed until after the storm passes.
* At Energy’s Indian Point, protection of the two reactors there focuses on possible wind damage to the switch yard. If off-site power is lost, the plant will run on emergency diesel generators.
* Similar preparations are underway at Constellation’s two reactors at Calvert Cliffs, MD, and, at PSEG’s Salem and Hope Creek reactors which face the Delaware River estuary in southwestern NJ.
* At Constellation plant manager said that staff working in the Emergency Response Organization (ERO) will be tasked to 12 hour duty shifts and all ERO personnel will remain on site. Staff use a checklist to insure they bring necessary items with them for the shifts. Sleeping areas and round the clock cafeteria access are mobilized for the duration.
* At Exelon’s Oyster Creek reactor, which faces the Atlantic ocean in southeastern NJ, workers are securing equipment that might be impacted by high winds. Emergency diesel generators are checked to insure they are ready to run and have reserves of fuel.
* In North Carolina Progress Energy began preparations on Wednesday of this week at its Harris and Brunswick plants. Brunswick is designed to withstand a storm surge of 22 feet above sea level. The plant will continue to operate unless winds rise above 75 mph.
Plants are built to withstand high winds
Nuclear energy facilities are designed to withstand natural occurrences greater than those encountered in the regions where they are located. They are built to withstand floods, earthquakes and high winds, and have numerous safety systems that will operate and safely shut the reactor down in the event of a loss of off-site power. These plant designs are routinely reviewed and modifications are made to assure their integrity and safety.
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