Southern California Edison (SCE) has asked the Nuclear Regulatory Commission (NRC) to begin the process for restarting one of the two idle 1,100-MW units at the San Onofre Generating Nuclear Station (SONGS) at reduced power.
The Edison International (NYSE: EIX) subsidiary said Oct. 4 that it has submitted its response to the NRC’s Confirmatory Action Letter (CAL), which was issued in March, along with its restart plan for San Onofre 2.
The company wants to restart Unit 2 at 70% power. SCE would effectively do a five-month test run at 70% power and then shut down Unit 2 to check on potential tube wear.
Neither unit at the San Diego County facility can be restarted until all plans have been approved by NRC. Some nuclear power critics have said previously that restarting either unit at partial power is not a long-term solution to the problems at San Onofre.
NRC won’t be rushed; process will take months
NRC Chair Allison Macfarlane told a Senate panel recently that the agency would probably take months rather than weeks to review the utility’s submission and decide whether it is safe for the unit to return to service.
Macfarlane stressed that again Oct. 4.
“Our primary focus now must be on analyzing SCE’s response to the CAL before addressing the restart question. The agency will not permit a restart unless and until we can conclude the reactor can be operated safely,” Macfarlane said. “This could take a number of months. Our inspections and review will be painstaking, thorough and will not be rushed.”
News of a potential Unit 2 restart would likely be welcomed by the California Independent System Operator (Cal ISO), which had to use a couple of backup fossil units this summer that had been scheduled for mothball status.
SONGS Units 2 and 3 have been idle since January when unusual tube wear was discovered at steam generators that were less than two years old. There was a small radioactive release reported in January.
No San Onofre 3 filing until at least summer 2013
Company officials have said the wear problem is more serious at Unit 3. As a result, San Onofre 3 has been defueled in anticipation of a longer outage. “The reality is that the Unit 3 reactor will not be operating for some time,” an SCE official said during a conference call with reporters.
The utility does not expect to make any similar NRC filing on Unit 3 before the summer of 2013.
It is not yet known if the Unit 3 steam generators can be repaired or will have to be replaced, SCE officials acknowledged.
It’s important to get San Onofre 2 back online, even at a reduced level, SCE officials said. They said Southern California was lucky to have a mild summer and a good conservation effort by ratepayers in recent months.
Long-term loss of the nuclear reactors would require SCE to make other electric generation and transmission upgrades, both of which would be costly and take a long time to develop, utility officials said.
The response and restart plans are being submitted simultaneously to provide the NRC with all the relevant information needed to evaluate the full spectrum of repairs, corrective actions and additional safety measures proposed for restart and safe operations at the plant, the utility said.
“Safety is our top priority, and after conducting more than 170,000 inspections to understand and prevent the problem, and confirming the corrective actions we have taken to solve the problem with the top experts from around the world, we have concluded that Unit 2 at San Onofre can be operated safely and within industry norms,” said SCE President Ron Litzinger.
The response to the NRC covers the causes of the tube wear, repairs and corrective actions required for the Unit 2 steam generators, actions to prevent the extensive tube-to-tube wear observed in Unit 3, and inspection and safe operation protocols.
SCE said the tube-to-tube wear in the Unit 3 steam generators was caused by a phenomenon called fluid elastic instability, a combination of high-steam velocity and low-moisture conditions in specific locations of the tube bundles and ineffective tube supports in the same locations.
The utility said it will be installing early warning monitors that can detect extremely small tube leaks faster.
SCE owns more than 78% of the two-unit plant (Unit 1 was retired years ago). A Sempra Energy (NYSE: SRE) subsidiary and the City of Riverside are minority stakeholders.
Unit 2 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 small leak in a steam generator tube.
The outage has become something of a political football in California where nuclear energy has much public opposition. During a Senate hearing this summer, Sen. Barbara Boxer, D-Calif., stressed to NRC that the reactors cannot be allowed to operate before they are proven safe.
Prior to SCE’s Oct. 4 announcement, NRC had already scheduled a public meeting this month in California on the San Onofre problems.