Aging East Coast reactors proved resilient as the historic storm Sandy pummeled New York and New Jersey with driving winds and widespread flooding that left 59 people dead and more than 8 million without power.

The sprawling hurricane roared ashore near Atlantic City, N.J., on Monday, forcing power plant operators to shut down three nuclear reactors in New York and New Jersey and to reduce power production at units in Pennsylvania and Connecticut after the storm wiped out swaths of the electric grid.

Industry officials quickly pointed out that 34 plants in the storm's path either were safely powered down or ran at full power.

In New Jersey, Exelon Corp. issued a rare alert at its sidelined Oyster Creek plant in Lacey Township -- the nation's oldest reactor -- after storm surge in the Barnegat Bay pushed levels to more than 7.4 feet above normal, high enough to threaten non-safety cooling water pumps, according to the Nuclear Regulatory Commission.

Although the reactor had been shut down since Oct. 22 for refueling and maintenance and was not at risk, regulators were concerned that the flood would cripple electrical pumps needed to route cooling water to hot, radioactive spent fuel rods, NRC spokesman Neil Sheehan said. Exelon was forced to power up two emergency diesel generators to run the plant's safety system after high winds partially knocked out power to the site, he added.

But the alert has ended, no pumps were damaged, power has since been restored to the site and Oyster Creek operators didn't need to use a portable pump that was staged near the bay as a precautionary measure, according to Exelon and the NRC.

If the storm surge had knocked out a second, more critical set of pumps needed to cool the reactor and backup diesel generators, operators had a second line of defense for the reactor -- an "isolation condenser" -- that can remove heat from the core after shutdown, said David Lochbaum, director of the nonprofit Union of Concerned Scientists' Nuclear Safety Project.

And Exelon, like other operators, had stockpiled portable pumps, generators and other equipment following the Sept. 11, 2001, terrorist attacks that would have ensured the condenser had sufficient water, Lochbaum added.

"Had a much worse storm happened, and all the primary and backup cooling systems were lost, they could have dipped in the 9/11 cabinet and used that equipment to get water into the isolation condenser," he said.

A nuclear plant about 100 miles southwest of the Oyster Creek power station ran into similar problems.

Public Service Enterprise Group Inc. shuttered its Salem Unit 1 reactor in Hancocks Bridge, N.J., near the Delaware River, after a structure housing four of the station's six electrical pumps -- also used to cool steam for power production -- was battered by waves up to 15 feet tall and clogged with debris. PSEG is investigating whether the water damaged the pumps.

Other plants were forced to pull back power or go offline after forceful gales knocked down large swaths of the Northeast grid, creating electric anomalies.

Entergy Corp.'s Indian Point Unit 3, about 45 miles north of New York City, automatically went offline when the connection between an on-site generator and the electric grid was lost. Another unit at the plant is still operating at full power. Exelon reduced power production at its Limerick plant near Philadelphia, and Dominion Resources did the same at its Millstone plant near New London, Conn., to maintain grid stability.

In New York, strong winds knocked down power lines leading to Unit 2 of Constellation Energy Nuclear Group's Nine Mile plant near Oswego, but those lines have since been restored. Constellation is also investigating why an electrical disturbance triggered the automatic shutdown of Unit 2 at the Nine Mile plant after equipment needed to protect the site's switchyard from lightning was blown over, said Jill Lyon, a spokeswoman for the company.

Despite the outages, the safety systems operated as they should have, Lyon said.

Lake Barrett, the former head of the Department of Energy's Office of Civilian Radioactive Waste Management, wasn't surprised the reactors were safe throughout the storm, because the industry has a robust safety regime in place.

"It was certainly a storm of epic proportions, and because there wasn't a problem, it demonstrates there's a significant safety margin, which [plant operators] should and do have," Barrett said. "I would've been shocked if there was an increased safety risk of any significance."

Safety upgrades

But Lochbaum said far-reaching, hard-to-predict storms like Sandy highlight vulnerabilities that exist within the nuclear industry's defense against rare and dangerous events, as well as the need for new safety rules after the magnitude-9 earthquake and tsunami that crippled Japan's Fukushima Daiichi nuclear plant last year.

"Fukushima taught us we need to expand our horizons," he said. "This storm reinforced that we need to do it sooner than later."

The NRC is currently rolling out new rules to protect plants from rare storms, fires, earthquakes and other disasters in response to the Japanese accident.

The issue of climate change has also entered the conversation. NRC Chairwoman Allison Macfarlane has asked agency staff to study how reactors are affected by climate change after rising seawater temperatures forced an unprecedented shutdown last month of a Connecticut reactor (Greenwire, Sept. 14).

The problem, Lochbaum said, is that U.S. reactors weren't built with storms like Sandy in mind. Instead, the facilities were built to withstand the worst historical storms and earthquakes for their respective regions, he said.

Japanese engineers similarly depended on -- and misused -- historical tsunami data when building a sea wall to protect the Fukushima Daiichi plant, but a 46-foot tidal wave topped the existing sea wall and knocked out power needed to cool three overheating reactors. NRC Commissioner George Apostolakis said last year that no U.S. company would be allowed to make the same mistake (Greenwire, Aug. 3, 2011).

"The Japanese looked backwards, too," Lochbaum said, adding that operators of the Fukushima plant didn't look carefully enough at future threats while considering historic events. The United States should be wary of that approach, he said. "If history goes into some new place, our protections might not be adequate."

But Barrett said the nuclear industry and NRC are constantly reviewing the types of threats that plants face and pointed to the agency's post-Fukushima review as a case in point.

Another overarching concern is that workers may not be sufficiently trained to use emergency equipment, Lochbaum said. The NRC's probe of the industry last summer found many plants had fallen behind on training staff on procedures for managing severe accidents (E&ENews PM, June 6, 2011).

"Our concern is that the 9/11 equipment is physically there, but workers don't get trained on it," he said. "The middle of an emergency isn't the time to find out you don't have the right wrench."

Massive flooding, downed trees and damage to the country's infrastructure also threaten to block first responders from delivering emergency equipment to crippled reactors, he said.

The industry has acknowledged that threat, and the Nuclear Energy Institute last week announced it would create two hubs near Memphis, Tenn., and Phoenix, Ariz. -- slated to cost about $1 million each -- to store portable emergency equipment to power and cool crippled U.S. reactors during wide-scale disasters.

Alabama-based Pooled Equipment Inventory Co. and French nuclear giant Areva will run the centers, where utilities will be able to access generators, pumps, radiation protection equipment and other emergency response equipment to an affected site within the first 24 hours of an extreme event.

Lochbaum dismissed criticism that the NRC is taking too long to roll out its new rules, and instead said the agency is striking the right balance.

"The NRC has been criticized by some for the pace of the response," he said. "I'd rather take the time to get it right."

Reporter Peter Behr contributed.