According to officials from Pacific Gas & Electric, the Diablo Canyon nuclear power plant isn’t susceptible to the same catastrophic failures as Japan’s Fukushima Daiichi, which is currently belching out radioactive material after several of its units exploded.
“There are some very significant differences,” John Conway, PG&E senior vice president and chief nuclear officer, said of Diablo Canyon and Fukushim Daiichi when he updated the San Luis Obispo County Board of Supervisors on March 15.
Conway said Japan’s plant was taken down not by the massive earthquake that rocked the island country on March 10, but by the subsequent tsunamis. That plant was set to withstand 20-foot waves, but was flooded by waves that reached 21 to 22 feet, he said.
Diablo Canyon, on the other hand, is prepared to handle 35-foot waves.
Additionally, the plant has a higher threshold for “acceleration” caused by an earthquake.
It all sounded good, but, as county supervisors noted, PG&E’s claims that what happened in Japan won’t happen here are based on assumptions—the same type that proved false in that country.
“I’ve sat with your seismic experts; I’ve sat with your engineer experts; and [I] understand the design assumptions,” Supervisor Bruce Gibson said.
PG&E is working to have Diablo Canyon relicensed by the Nuclear Regulatory Commission for another 20 years. The licenses for its units expire in 2024 and 2025, respectively, so this relicensing effort is well ahead of deadline. The company has faced intensive scrutiny from county officials, the public, Sen. Sam Blakeslee, and the California Public Utilities Commission, who have all pressured PG&E to commit to more detailed seismic studies.
A new fault line—the so-called Shoreline fault—was recently discovered, which
places Diablo Canyon within miles of that seismic feature on top of the already known Hosgri fault.
Supervisor Adam Hill asked PG&E to give regular updates as new information becomes available.
“This is really the start of what needs to
be a very thorough public discussion,” Gibson said.
This article appears in Mar 17-24, 2011.