By Karl Henkel
Nuclear power reactors near the Mahoning Valley, such as two in nearby Shippingport, Pa., wouldn’t stand a chance against the series of cataclysmic natural disasters that hit Japan’s west coast March 11, which included a magnitude 9.0 earthquake and tsunami.
In fact, Shippingport’s reactors, Beaver Valley 1 and 2, are equipped to withstand an earthquake of at least a magnitude 5.8, according to Akron-based FirstEnergy Corp., operator of the plants.
Pennsylvania’s most intense earthquake to date is a magnitude 5.2 in 1998, according to the U.S. Geological Survey. So it’s reasonably acceptable that Beaver Valley wouldn’t need to sustain larger earthquakes, such as the El Diablo Canyon Power Plant near the potentially powerful San Andreas fault line in Southern California.
Beaver Valley 1, though, found itself as a top-five member of a disturbing list compiled last week by MSNBC: Most at-risk nuclear facilities for earthquake damage.
Of the 104 commercial facilities in the country, Beaver 1, built in the 1970s — Beaver 2 came a decade later — placed fifth on the list, though FirstEnergy didn’t agree with the methodology used in the study, and Youngstown State geology professor Raymond Beiersdorfer said the Valley isn’t expected to see bigger earthquakes anytime soon.
The Valley did experience a small, 2.6 magnitude earthquake Thursday morning, its first since records have been kept. Michael Hansen of the Ohio Seismic Network said it most likely occurred at an ancient buried fault of basement rocks that could be up to 1 billion years old.
The Nuclear Regulatory Commission issued a release Friday saying its assessments are used only as a “screening tool” and that it does not rank plants by seismic risk.
Other plants near the Valley, such as in Perry, can withstand an earthquake of at least a magnitude 6.0. Both Perry and Shippingport are designed to withstand more likely acts of nature, too, such as floods and tornadoes, said John Stevenson, an engineer from Ohio and a member of the International Seismic Safety Center. Those include floods, tornadoes and earthquakes.
That’s because nuclear plants, much like people, are principally the same, yet no two are exactly alike; they’re built to the risks associated with their locations.
Massachusetts Institute of Technology professor Andrew Kadak said the designs of plants are given additional margins.
“Instead of redesigning every plant, the design is robust enough to handle what people would expect,” he said. “Doing anything more is unnecessary and just a waste of money.”
Structurally, none of the reactors in or near Ohio is exactly the same as the six at the Dai-ichi plant in Fukushima, Japan.
The one most similar is the Perry plant, a boiling-water reactor manufactured by General Electric. It’s a Type 6. Dai-ichi was made up of types 3, 4 and 5.
Like car models, which update slightly each year, so do nuclear-reactor facilities. Kadak said the type models all are functionally similar, just slightly modified to correct any previous issues from earlier versions.
The Type 6 in Perry also has another significant difference: a larger containment cap, with thicker walls and more volume.
As for backup plans in case of emergency, the Perry facility is much like Dai-ichi, which was stricken with electric failure due to the earthquake, then was dealt a second blow when the tsunami washed away its diesel generators and the battery-operated cooling system also failed.
Perry’s generators are located underground — unlike Japan’s — which could be both a good and bad thing, Kadak said, because if they’re underground, there’s a chance in a flood — even if they’re protected — that they’re under water.
Dai-ichi workers were forced to use seawater in an attempt to cool reactors and prevent a meltdown.
Perry, situated near Lake Erie, has four backup cooling systems that draw water directly from the lake.
The nearby water could help prevent the plant from becoming a historical nuclear accident such as Three Mile Island’s, a 1979 nuclear-reactor leak regarded as the second-worst nuclear accident in history after Chernobyl, which occurred in 1986.
But FirstEnergy’s Davis-Besse plant, located about 30 miles east of Toledo in Oak Harbor, has had its own problems.
One incident, in 2002, revealed corrosion in a nuclear-reactor head, and FirstEnergy was fined about $28 million and had to shut down the plant for nearly two years.
Kadak said plants are designed to handle human errors, as shown by numerous backup capabilities, and that the Davis-Besse incident was more of an “operational” issue.
Davis-Besse reactors also had to power down last May for a week after an emergency shutdown system failed.
FirstEnergy spokesman Todd Schneider said it was a loss of power to pumps that deal with the control-rod drive, which interacts with fuel rods.
Fuel rods in Perry, when unusable or “spent,” are stored in a containment-style large pool of water. Schneider said the water blocks the spread of radiation as if a person was “shooting a bullet into the water — the water would stop the bullet.”
Previously slated to be a two-reactor plant, Perry has more than enough room to accommodate the spent rods; other plants also use dry-cast storage (encased in cement).
Regardless of the reason, the chance of an incident such as Japan’s happening in the states isn’t likely.
“I would consider it an overblown concern,” Stevenson said. “The truth of the matter is, we’re surrounded by potential natural hazards all [of] the time.”
Kadak and Stevenson both said the Japan scenario was a result of two back-to-back disasters, and Kadak said it’s much too early to point blame, either at human neglect or design failure.
“Until we understand what happened,” he said, “it’s really, really too soon to try and find a solution.”