A new technical evaluation of San Onofre Nuclear Generating Station Unit 2 demonstrates that the Unit 2 steam generators could be operated safely at 100 percent power and reinforces Southern California Edison's (SCE) more conservative plan to begin operating Unit 2 at 70 percent power for five months.
SCE submitted the operational assessment of potential Unit 2 steam generator tube wear to the Nuclear Regulatory Commission in response to NRC questions. The new evaluation determined Unit 2 could operate at full power for 11 months with full tube integrity.
The assessment was performed by Intertek APTECH of Sunnyvale, CA, and supplements Intertek's earlier assessment of Unit 2 operation at 70 percent power. Intertek performs operational assessments relating to steam generators for many nuclear power plants around the U.S.
"This evaluation confirms the structural integrity of the Unit 2 steam generators at 100 percent power, as requested by the NRC," said Pete Dietrich, SCE senior vice president and chief nuclear officer. "While we have no intent to restart Unit 2 at full power, this demonstrates the amount of safety margin we have built into our analyses. We welcome this additional safety analysis but remain steadfast in our commitment to restart Unit 2 at only 70 percent power."
SCE has proposed the reduced power operating level to prevent the conditions that caused premature tube wear in San Onofre Unit 3 and indications of wear in Unit 2.
The San Onofre nuclear plant is the largest source of baseload generation and voltage support in the region and is a critical asset in meeting California's summer electricity and clean energy needs. Both units at San Onofre are currently safely shut down. Unit 2 remains shut down since it was taken out of service Jan. 9, 2012, for a planned outage. Unit 3 was safely taken offline Jan. 31, 2012, after station operators detected a leak in a steam generator tube.
NRC approval is required before SCE can restart Unit 2.
SCE serves nearly 14 million via 4.9 million customer accounts in a 50,000-square-mile service area within Central, Coastal and Southern California.