Southern California Edison plans to escalate the proposed $4.4 million it seeks for seismic studies in its general rate case to $64 million in the wake of Japan’s Fukushima nuclear disaster. Edison outlined its expanded seismic study for the two-unit San Onofre Nuclear Generating Station in an April 15 request to the California Public Utilities Commission. Two known faults run off the coast of the beach-side facility--the Inglewood-Newport-Rose Canyon Fault, which the U.S. Geological Survey estimates could create a 7.2 magnitude shaker, and a more-recently discovered fault that runs from Laguna Beach to Mexico, which USGS geologists say could trigger a magnitude 7.6 quake. San Onofre is designed to withstand a magnitude 7.0 quake (Current, March 25, 2011). The plant also is in an area that could be affected by a magnitude 8.5 quake on the San Andreas fault, according to Jon Stewart, professor of civil engineering and seismic safety at the University of California at Los Angeles (see sidebar). Edison told the commission the unexpected events at the Fukushima Daiichi plant showed “it was prudent to re-evaluate the scope of its seismic work” so the utility can “broaden scientific understanding of the seismic and tsunami conditions that could affect the plant.” Depending upon the outcome of the study, Edison may propose seismic upgrades at the 2,150 MW plant, said utility spokesperson Gil Alexander. The Nuclear Regulatory Commission can evaluate the upgrade issues, but federal regulators have no obligation to review studies underwritten by California ratepayers, according to NRC sources. Alexander said Edison wants the CPUC to expedite action on its funding request so it can begin the study as quickly as possible. Originally, the company asked the commission to approve $4.4 million for ongoing seismic studies prior to the Japanese quake. After the quake and problems at the Japanese reactors, he said the company filed its request to authorize a more comprehensive probe of the faults near the plant using new two- and three-dimensional sensing technology. The new sensing method creates more complete pictures of faults that improve the ability of scientists to assess their earthquake potentials. Edison projects that if state regulators approve funding by October, it could complete the seismic assessment by 2015. While Alexander said the company would act on seismic upgrades when warranted, it still has not decided whether to pursue a 20-year operating license extension. The current license allows the utility to operate the plant through 2022. In its general rate case for 2012 through 2014--which is pending before the CPUC--the utility is asking regulators to authorize more than $358 million in upgrades for the plant. Major proposed expenditures include: -$110.7 million to replace the heads on each of the two reactor units; -$82.1 million for dry cask storage for spent fuel; -$18.4 million to replace eroded pipe work; and -$73.1 million for turbine retrofits. The request also includes $4.1 million to replace the emergency backup diesel generator system to maintain plant power in the case of a loss of power from the grid. The utility told the CPUC the engines suffer from “age-related wearing.” Edison also is requesting $5.7 million to upgrade the plant’s control room and $1.5 million for remodeling the cafeteria. Edison is allowed an 11.5 percent rate of return on its capital expenditures. In 2005, state regulators authorized San Onofre owners to spend up to $782 million to replace steam generators at the facility. Edison owns 78.21 percent of the plant, San Diego Gas & Electric 20 percent, and the City of Riverside 1.79 percent. Edison operates the plant, which opened in 1982.
