HOUSTON Oct 12 The U.S. Nuclear Regulatory
Commission said its latest analysis of seismic faults near PG&E
Corp's Diablo Canyon nuclear station in California
showed the coastal plant could withstand an earthquake generated
by an offshore fault identified in 2008, according to a
statement on Friday.
The NRC's report focuses on the latest identified earthquake
source, called the "Shoreline fault," just offshore from the
plant in San Luis Obispo County, about 183 miles (294 km)
northwest of Los Angeles.
Diablo Canyon operator Pacific Gas & Electric said it
welcomed the NRC finding "which confirms that Diablo Canyon is
seismically safe and is designed to withstand the maximum ground
motions that seismic faults in the region are believed capable
of producing," in a separate statement.
PG&E notified the NRC about the Shoreline fault in 2008. At
2,240 megawatts, Diablo Canyon is the larger of the state's two
nuclear power plants, supplying about 10 percent of the state's
"Both PG&E and the NRC are continuing to look at the seismic
characteristics of the Shoreline fault," said NRC spokesman
Victor Dricks. "This research information letter represents the
staff's latest analysis and basically concludes that the plant,
as designed, would withstand any earthquake the Shoreline fault
An NRC team visited the site in 2011, the agency said.
Analysis from the visit and available information indicates that
ground motion from earthquakes the Shoreline fault could
potentially generate would fall within Diablo Canyon's existing
design limits, the agency said in its report.
The plant's design limits are based on ground motion
associated with an earthquake from the larger Hosgri fault near
the plant, the NRC said.
Separately, PG&E is performing a $64 million seismic
research effort mandated by the state legislature using
three-dimensional seismic tests to better understand the hazards
posed by potential earthquakes near the plant.
In August, the California State Lands Commission voted to
allow the utility to move forward with the advanced tests using
powerful sonar devices despite concerns about the impact on
At the request of the utility, its NRC application to extend
the two Diablo Canyon reactors' operating licenses beyond 2024
and 2025 will not be finalized until the advanced seismic
research called for by the state is completed.
For the NRC, Diablo Canyon must perform additional
earthquake evaluations, as well as a "walkdown" to identify any
near-term actions for enhancing earthquake resistance as part of
the agency's ongoing response to the 2011 Fukushima Daiichi
nuclear accident in Japan which was triggered by an earthquake
"As part of our strong commitment to safety, PG&E has and
will continue to study the seismicity of the region to give us,
our regulators and the public confidence that the plant remains
safe," the utility said.