Dec 3, 2014 2:38 PM
California nuke plant key in quake safety review
The Associated Press
WASHINGTON (AP) Democratic Sen. Barbara Boxer criticized members of the Nuclear Regulatory Commission Wednesday for not doing enough to ensure that California's last operating nuclear power plant is safe in light of new seismic faults not recognized when the plant was constructed decades ago.
Boxer pointed out that a senior federal expert has urged the NRC to shut down the Diablo Canyon plant until it can determine whether the reactors can withstand shaking from any of several nearby faults. She said her concerns went beyond her home state, though, saying the agency has yet to fully complete any of 12 key safety recommendations that a task force made after Japan's Fukushima nuclear disaster more than three years ago.
The NRC's outgoing chairman, Allison Macfarlane, told Boxer that nuclear plants in the U.S. are indeed safer since Fukushima. Some have built earthquake proof shelters to make sure their reactors are protected. Others have installed new pumps and other equipment to deal with flooding. Macfarlane said the Diablo Canyon plant was safe to operate and she noted that the inspector Boxer cited acknowledged there was no "immediate" threat to the plant. If the NRC believed the plant were unsafe, it would act, she said.
"Immediate is not good enough for this senator. Immediate is not good enough for the 500,000 people who live within 50 miles. Immediate. That's what they said at Fukushima," Boxer said.
After commissioners addressed questions from senators on an array of nuclear industry issues, a former California state senator told the Senate Committee on Environment and Public Works that federal regulators need to reassess seismic standards at Diablo Canyon's twin towers and determine if its operating rules are sufficient in light of earthquake risks. The NRC and owner Pacific Gas and Electric Co. have long defended its safety.
Sam Blakeslee argued that public safety demands closer scrutiny of Diablo Canyon's twin reactors, located near several faults on a seaside bluff midway between Los Angeles and San Francisco.
"The potential earthquakes affecting the plant have increased with each major study. But what's equally striking is that the shaking predicted by PG&E for these increasing threats has systematically decreased," said Blakeslee, a geophysicist who left the Legislature in 2012.
Blakeslee and Daniel Hirsch, a lecturer at the University of California, Santa Cruz, both expressed concerns that the lessons of Fukushima have not been learned, and that's critical in light of new fault lines discovered near the nuclear plant.
In the 2011 Fukushima Dai-ichi disaster, the coastal complex suffered multiple meltdowns after an earthquake and tsunami destroyed its power and cooling systems. The magnitude-9.0 earthquake was far larger than had been believed possible. Hirsch said that when Diablo Canyon was designed and granted a construction permit, PG&E and the NRC said there were no active faults within 30 kilometers of the plant. He said that at least four earthquake faults have been discovered in the vicinity since.
The Associated Press reported in August that a senior federal nuclear expert had urged the NRC to shut down the plant until it can determine whether the reactors can withstand shaking from any of several nearby faults not recognized when the plant was constructed decades ago.
The agency rejected the recommendation from Michael Peck, who was the NRC's lead inspector at the plant for five years. The NRC found there was no immediate or significant safety concern.
The agency's ruling was issued on the same day that PG&E released hundreds of pages of scientific research that found a fault 650 yards from the reactors is twice as long as initially believed, making it capable of producing potentially stronger earthquakes, and intersections between some faults in the region could create larger earthquakes than previously considered.
Anthony Pietrangelo, a senior vice president for the Nuclear Energy Institute, a trade group, said it's not unusual for the NRC's staff to voice differing opinions on safety issues, and he took issue with any assertion that Peck's warnings were ignored. "No one was silencing anybody," Pietrangelo said.
PG&E said in a statement that the plant remains seismically safe and able to withstand the largest potential earthquakes.
Blakeslee argued that the company has downplayed risks and criticizes the NRC for largely going along.
"Now that the data about the faults near Diablo is indisputable, PG&E has changed tactics and declared the plant is safe on the basis of a new set of equations it has developed," he said.
Peck's report says PG&E research in 2011 determined that any of three nearby faults the Shoreline, Los Osos and San Luis Bay are capable of producing significantly more ground motion during an earthquake than was accounted for in the design of important plant equipment.
Peck's confidential analysis, later released by the NRC, argued that the agency should shut down the plant until it is proven that piping and other systems can meet higher stress levels or approve exemptions that would allow the reactors to continue to operate.
An internal NRC review panel disagreed with Peck on key points, concluding that the three faults "do not exceed the level of ground motion already considered in the design and licensing" of the plant.