Concerns, assurances over Calvert Cliffs and Peach Bottom

Potential design issues, safety lapses spark criticism, but companies say nuclear power plants are safe

March 21, 2011|By Timothy B. Wheeler, The Baltimore Sun

Like many Americans, Linda Billings has been following news of the unfolding crisis in earthquake-rocked Japan, where a crippled nuclear power plant teeters on the brink of a disastrous meltdown.

But the 55-year-old Street resident is paying perhaps a bit more attention than most. Her home in northern Harford County is less than 10 miles from a similarly designed nuclear plant just across the border in Pennsylvania.

"I've not worried about it, but perhaps I should," she said late last week. "It would certainly be nice to know the U.S. plants are safer."

Industry spokesmen say the 104 nuclear power reactors operating in the United States — including two in Southern Maryland and the two just north of the Harford line in Delta, Pa. — are "the safest in the world." Each has redundant safety systems and highly trained workers ready to respond to all manner of emergencies, the spokesmen say.

"We don't have any reason to believe that the U.S. plants aren't safe,'' said Nuclear Regulatory Commission spokesman Neil Sheehan. "The Japanese reactors were confronted with a very unlikely set of circumstances — the fifth-largest recorded earthquake followed by a tremendous tsunami. … This is really beyond what anybody could have conceived of."

But the calamity that's unfolded in Japan has prompted the Obama administration to call for a thorough review of the safety of U.S. nuclear plants. The five-member NRC is to meet Monday in Rockville to review how the Fukushima incident might highlight the need to make further safety improvements in this country.

More than 77,000 Marylanders live within 10 miles of a pair of nuclear power plants, the Peach Bottom facility in Delta and Calvert Cliffs. But many more live within 50 miles — the distance at which U.S. officials were urging Americans in Japan to get from the damaged Fukushima plant. Peach Bottom is about 45 miles from Baltimore; Calvert Cliffs is 74 miles away.

Earthquakes are generally mild in this region, and tsunamis are unheard of. Industry experts point out that plants are designed to withstand the worst recorded tremors in a given location.

At Calvert Cliffs, built on the shore of the Chesapeake Bay, even the backup diesel generators that might be needed in an emergency are placed inside quake-resistant structures beyond the reach of the highest flooding anyone expects from a hurricane in these parts — about 16 feet, according to Mark C. Sullivan, spokesman for Constellation Energy Nuclear Group, which owns the plant.

And Peach Bottom on the Susquehanna River, says David Tillman, spokesman for Chicago-based Exelon Corp., is prepared for flooding, droughts and even dam breaks that might affect their supply of water to keep its twin reactors from overheating.

"We're prepared for high water, we're prepared for low water — we're prepared for no water," Tillman said.

But nuclear energy critics said power plants in this region could get into similarly serious trouble if some other unanticipated event occurred that was then compounded by failures of key safety equipment and worker mistakes. And others point to incidents last year at Peach Bottom and Calvert Cliffs, which they said demonstrate troubling lapses in attention to safety.

"It doesn't need to be an earthquake and tsunami in Pennsylvania or Maryland to initiate it," said Paul Gunter of Beyond Nuclear, an anti-nuclear group in Takoma Park. "It could be a different set of initiators, starting with a tree limb on a transmission line that shuts down the power," he added. If backup diesel generators fail to work for any reason, then U.S. plants also would have to rely on emergency batteries to maintain necessary safety systems for just four to eight hours.

Critics also note that there have been longstanding safety concerns voiced about the design of the reactors in Japan — and that there are 23 of the same type in this country, including two at Peach Bottom.

Mark 1: pros, cons

Most U.S. reactors, including those at Calvert Cliffs, are pressurized water reactors, in which the reactor core is sealed inside a thick containment chamber of steel and concrete. But Peach Bottom and the Fukushima plant have "Mark 1" boiling-water reactors, made by General Electric Co., in which the same water used to cool the reactor converts to steam to drive the turbines.

In 1972, a safety official with the Atomic Energy Commission, the government precursor to the Nuclear Regulatory Commission, warned that the Mark 1 was susceptible to hydrogen gas building up inside, exploding and breaching the containment, releasing dangerous radiation. Another NRC official voiced similar concerns in the 1980s.

"Peach Bottom Units 2 and 3 are dead ringers for the Fukushima reactor design that's now hanging on a catastrophe," said Gunter.

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