Local nuclear plants undergoing internal probes in wake of Japan disaster

Health news Health & Medical News Exelon predicts U.S. nuclear reviews

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Exelon predicts U.S. nuclear reviews

As part of a worldwide reexamination of nuclear power in the aftermath of Japan's tsunami, America's largest nuclear-power producer anticipates that U.S. regulators will conduct a thorough - and costly - review of safety systems at the nation's 104 reactors.

Leaders of Exelon Corp. - which operates 17 U.S. nuclear-power plants, including the reactors closest to Philadelphia - said Thursday that the company has already launched internal investigations of its plants in response to Japan's unfolding nuclear catastrophe.

But John W. Rowe, Exelon's chairman and chief executive, told investment analysts that the company is confident of the safety of the reactors it operates at 11 sites in Pennsylvania, New Jersey, and Illinois.

"Our plants are not subject to the same earthquake and tsunami risks that have been experienced in Japan," Rowe said. "And despite the fact that they differ in some other material respects, we have begun focused safety reviews since the event, and our reviews to date continue to assure us that our plants are safe."

Exelon's reactors include Limerick Generating Station in Montgomery County; Peach Bottom Atomic Power Station in York County, Pa.; Oyster Creek Generating Station in Forked River, N.J., and Three Mile Island Unit 1 outside Middletown, Pa.

The Oyster Creek plant and the two Peach Bottom units have a design similar to the Japanese reactors'.

Rowe's expression of confidence in nuclear power - he called Exelon's fleet "the biggest asset in the American energy industry" - comes as support appears to be wavering for rejuvenation of a business that stagnated after the 1979 accident at Three Mile Island's Unit 2.
The Union of Concerned Scientists, a nonprofit American nuclear watchdog, has stepped up its calls for the Nuclear Regulatory Commission to more strictly monitor U.S. reactors.

"U.S. plants have the same key vulnerability that led to the crisis in Japan," the organization said in a statement.

An audit by the NRC's inspector general, released Thursday, also raised questions about the agency's oversight, saying reporting guidelines for the nuclear industry are "contradictory and unclear."

Antinuclear movements in Italy and Germany have picked up momentum since the disaster at the Fukushima Dai-ichi reactors, where critical cooling systems were disabled by the tsunami, leaving the reactors defenseless.

And the Wall Street Journal reported this week that NRG Energy Inc. could delay or cancel plans to build two Texas reactors because investors and potential customers have grown more cautious.

Exelon, the parent of Philadelphia's Peco Energy Co., previously expressed no enthusiasm for building new nuclear plants in the near future. "But that view has come from the economics, not from safety," Rowe said.

And he noted that the Obama administration, the NRC, and key members of Congress have recently reiterated the importance of nuclear power, which supplies about 20 percent of the nation's electricity with limited greenhouse-gas emissions.

Rowe said Exelon believes the NRC will concentrate its attention on the viability of the 10-mile emergency-planning zone surrounding each reactor - the area plant operators and emergency-response officials would evacuate during a serious accident.

The review would focus on each plant's preparation for seismic events, on-site maintenance of spent fuel, and the adequacy of the General Electric Mark 1 reactor involved in the accidents at the Fukushima nuclear plant in Japan.

"We expect [the NRC] to impose both new hassles and new costs, but we will meet them thoroughly," Rowe said.

Exelon executives say they are paying close attention to industry reports about the damaged Japanese reactors, which they say appear to be stabilizing.

Four of the six Dai-ichi reactors were damaged beyond repair, said Christopher M. Crane, Exelon's president and chief operating officer.

"Everything we've seen so far suggests that the problems at the Japanese plants are event driven, not design-based driven," said Crane. "And there are some important differences between the plants - our plants and those in Japan."

He said the Japanese reactors appeared to have responded as designed and shut down during the magnitude-9.0 earthquake. But the 33-foot tsunami easily overwhelmed the 19-foot-high sea wall that protected the plant's critical safety systems.

The tsunami washed away the aboveground fuel tanks for the emergency diesel generators and flooded electrical switching equipment - both critical to cooling the reactor and the hot uranium fuel rods in the spent-fuel pools.

Though six of Exelon's reactors are the same design as the Dai-ichi units, Crane said the NRC has ordered "extensive modifications" in U.S. reactors since they were built more than 30 years ago.

The modifications include improvements to control hydrogen pressure in the containment, and the United States also requires multiple levels of backup power sources, he said. Emergency diesel tanks at Exelon plants are buried underground or are contained in protective boxes, he said.

A critical difference, Crane said, is that the Exelon reactors are located in "low-hazard earthquake zones and are designed to withstand the maximum historical ground-motion event at the sites with significant margin."

The Oyster Creek reactor in New Jersey, scheduled to be retired in 2019, is Exelon's only coastal plant. It is five miles inland, behind a barrier island 23 feet above sea level.

"In recorded history, there has never been a significant tsunami to hit the mid-Atlantic coast," he said.

Exelon's twin Limerick reactors are located on the Schuylkill, and the lowest safety-related structure is 10 feet above the "design-basis flood" level, Crane said. "This ensures that flooding of severe magnitude will still not affect the safety-related components at the site."

Exelon's officials said its spent-fuel cooling systems have multiple-backup storage systems to ensure that the fuel remains immersed in water during an emergency. At the Japanese plant, the failure of the cooling systems has caused water levels in the pools to drop, exposing the radioactive fuel to the air.

And seven Exelon plants, including Limerick, Peach Bottom, and Oyster Creek, are moving some of the spent fuel assemblies into stainless-steel canisters encased in concrete, the officials said. The so-called dry-cask storage requires no water for cooling.

The Japanese disaster raises questions about the ability of American reactors to withstand any blackout, including one resulting from terrorism or a cyber-attack.

But the Exelon executives said the company spent hundreds of millions of dollars improving security systems after the terror attacks of Sept. 11, 2001, during a nationwide NRC review of American reactors.

Unlike that review, in which security deficiencies were obvious, Exelon officials said, the Japanese disaster has not exposed glaring deficiencies in U.S. reactors.

Despite the differences, Rowe said, Fukushima is a series of events that simply wasn't supposed to happen.

A reminder of the gravity of nuclear safety sits next door to Exelon's Three Mile Island Unit 1 reactor, which it acquired in 2003.

"My entire management has been through the abandoned reactor in Three Mile Island," he said, "because we wanted to remind everyone of how serious failure is in this industry."

Source: Philly.com Health News , By Andrew Maykuth "Inquirer Staff Writer"

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