Ed. note: our hearts are with the people of Japan who are experiencing — again — the brutal downsides of human ingenuity, on top of the combined nightmare of two natural disasters. For a good live feed of news from NHK World TV, click here. For good information on the ongoing nuclear issues in Japan from the Union of Concerned Scientists, click here.
By Chris Burrell, The Patriot Ledger
Read the original article here
PLYMOUTH – The Pilgrim nuclear power plant runs the second-highest risk of catastrophic earthquake damage of all the nuclear plants in the country, according to a Nuclear Regulatory Commission study.
The Pilgrim Nuclear Power Plant in Plymouth (photo credit: Entergy Corp.)
The agency estimates the risk of an earthquake damaging the core of Pilgrim’s reactor over the course of a year at 1 in 14,493, a significantly higher risk assessment than its previous estimate of 1 in 125,000.
The federal agency considered both earthquake probability and the stalwartness of a nuclear plant’s design in tallying those odds.
Alan Kafka, a geophysicist and earthquake expert at Boston College, was surprised by the findings, expecting that the nuclear plants most at risk would be in California. But he agreed with the commission’s study.
“It’s like all the buildings in the East. We have fewer earthquakes, but at the same time we’re not as prepared,” he said. “California has about 100 times more earthquake activity than we have, but when an earthquake happens it has more effect in the East than in the West.”
The NRC study comes on the heels of concerns that the Pilgrim plant has the same reactor and containment design as the Fukushima Dai-ichi plant in Japan where workers and nuclear experts have been trying to thwart a meltdown in the aftermath of an earthquake and subsequent tsunami.
“They’re both built by General Electric,” said Paul Blanch, a nuclear energy consultant in Connecticut who works with local critics of Pilgrim in Plymouth. “Fukushima was put into service in 1971, and by age and design they’re almost identical. Pilgrim’s a little larger in size in terms of megawatt output.”
Both are also boiling-water reactors, and a report in Tuesday’s New York Times said some scientists have questioned whether these Mark 1 nuclear reactors built by General Electric – and in use both in Fukushima and Pilgrim – are more likely to fail in an emergency.
Nuclear safety officials in the 1970s and 1980s said the containment vessel surrounding the reactor was weak and prone to explosion, the Times report stated.
Pilgrim is one of 16 nuclear power plants in the United States with this reactor design.
But Mujid Kazimi, a nuclear physicist at MIT, who specializes in nuclear systems safety, said that Pilgrim has addressed this problem and modified its system since it opened in 1972.
“As part of a project 20 years ago, they did install a filtered vent, a capability to essentially avoid the destruction of the containment vessel by internal pressure,” he said.
While Kazimi acknowledged similarities in design between Pilgrim and the Japanese nuclear plant in crisis, he downplayed the risk posed to Pilgrim by natural disasters.
“In the U.S., we do use a system that requires the plants to be able to withstand expected earthquakes,” he said. “And I would expect Pilgrim would shut down safely.”
The nuclear disaster in Japan could offer lessons to Pilgrim in terms of sustaining energy supply, which is critical to cooling the reactor and spent fuel rods.
“Would we expect some event that would disable the onsite emergency generators? That is a bigger question,” said Kazimi. “Perhaps the location of diesel generators should be rethought.”
David Tarantino, a spokesman for the Pilgrim plant, said Pilgrim has three diesel generators to provide back-up power for the plant.
Christopher Burrell may be reached at cburrell@ledger.com.