Complete shutdown of the 2,200 MW San Onofre Nuclear Generating Station seems to have had little effect on power markets in California, with plenty of backup generation at the ready to replace its output and hardly a blip in the price of electricity. Unit 2 was shut down Jan. 9 for an estimated two months for routine refueling, plus a number of maintenance projects and component upgrades. Then Unit 3 had to be shut down due to an unexpected radioactive leak in a steam generator tube Jan. 31, taking the whole facility suddenly offline. An inspection revealed thinning of the walls of the steam tubes in both units (Current, Feb. 10, 2012). The Nuclear Regulatory Commission became involved and has completed inspecting all the tubes in Unit 2, according to spokesperson Victor Dricks. Following the inspection, he said, Southern California Edison already is plugging a number of the tubes in preparation for bringing the unit back on line once refueling and other maintenance work is completed. Edison spokesperson Gil Alexander said work on Unit 2 is “generally on schedule,” which means that it should be finished by next month enabling the 1,100 MW reactor to return to service. Dricks and Alexander both confirmed that examination of the steam generator tubes in Unit 3 is ongoing. Neither could say when the unit will be repaired and restored to service. Once restored, Unit 3 is due to be shut this fall for refueling and work similar to that being done on Unit 2. The work on both units--expected to cost $280 million--includes replacing the reactor heads and retrofitting the high-pressure turbines with new rotating and static components. The new reactor heads are single forge pieces without welds, so they are expected to be stronger, according to Edison. The California Public Utilities Commission initiated an investigation into the degenerating steam tubes, as well as a contract employee falling into a radioactive pool, according to Valerie Beck, California Public Utilities Commission’s Consumer Protection & Safety program manager, Feb. 16. Regulators are requiring Edison to provide at least two status reports a week on the facility. Meanwhile, on Feb. 13 with both units down, Califor-nia Independent System Operator data show 8,000 MW of spare generating capacity were at the ready to meet the state’s needs if demand exceeded the forecasted level of slightly less than 30,000 MW. Energy Information Administration data revealed little change in the price of power in Southern California in response to the reactor shutdown, with the wholesale day-ahead market hovering around $30/MWh. News of the expected restart of Unit 2 at San Onofre came as Pacific Gas & Electric Feb. 14 had to cut to half power one of its two units at Diablo Canyon to allow workers to unclog a cooling water intake that had filled up with debris. The work was expected to take a few days. The other unit remained fully operational, according to the Nuclear Regulatory Commission.
