Board to weigh in on renewal of Diablo Canyon nuclear power plant

The county Board of Supervisors is scheduled to weigh in March 9 on the thorny issues of license renewal and the threat of earthquakes at Diablo Canyon nuclear power plant.

On that day, the board is expected to consider requests by Supervisor Adam Hill, whose district includes the power plant, to send letters to state and federal regulators regarding plans by plant owners Pacific Gas and Electric Co. to conduct three-dimensional geophysical mapping of earthquake faults offshore of the power plant.

One letter would be to the California Public Utilities Commission in support of the studies. The other would be to the federal Nuclear Regulatory Commission asking that PG&E’s application for renewal of the plant’s two reactor operating licenses be suspended until the studies are complete.

On Jan. 15, PG&E applied to recover from ratepayers the $16.73 million it estimates it will cost to conduct the mapping over a three-year period. Late in 2008, PG&E’s ongoing seismic monitoring discovered the existence of a new fault, the Shoreline Fault, about 1,800 feet offshore of the plant.

The new fault and general concern about potential vulnerability of the nuclear plant to earthquakes have been dominant public issues since PG&E filed for license renewal in November. Mapping would provide more information about the faults and their earthquake potential.

“We are encouraged by the support shown for these expedited studies by our state’s regulators and state Legislature,” reads the letter Hill is proposing the board send to the NRC. “We have also been encouraged by PG&E’s willingness to complete the studies.”

The studies have the support of the California Energy Commission. Assemblyman Sam Blakeslee, R-San Luis Obispo, also supports further seismic study. He withdrew legislation that would have required the studies after PG&E applied to do the studies without legislative mandate.

As a cost-cutting measure, Gov. Arnold Schwarzenegger vetoed a previous Blakeslee bill passed by the Legislature requiring the studies. The state’s Division of Ratepayer Advocates, an agency tasked with keeping utility rates low, opposes them as unnecessary.

On Tuesday, the Board of Supervisors was scheduled to vote on whether to send the letter to the NRC requesting a delay of the license renewal. Hill has already sent his own letter to the NRC asking for the delay.

More than 20 people have expressed their support for the postponement either in writing or verbally to the board. However, PG&E opposes any delay, saying the window of opportunity for license renewal with the NRC is now, while the seismic mapping will take years to complete.

In the end, supervisors voted to postpone the whole matter until March 9, when both letters can be considered at the same time. The delay will also allow Supervisor Bruce Gibson, who was absent Tuesday, to participate in the discussion.