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On March 28, 2014 at 2110 PDT, station staff felt a minor seismic event, which was verified on the NEIC (National Earthquake Information Center). On-shift staff reviewed basis documentation and EAL (Emergency Action Levels) classification, and concluded the event was below the threshold to classify the event. During post event reviews (conducted on 3/31/2014), it has been determined that those events met the classification criteria for declaration of a Notification of Unusual Event for a seismic event as specified by the Emergency Plan. No emergency situation exists at this time.

Site personnel did perform the steps of the Earthquake abnormal operating procedure even though the entry requirements were not met.  There were no plant or equipment issues identified during the site walk downs.

The licensee has notified the NRC Resident Inspector, the State of California and other Local authorities.

A Notice of Unusual Event (NOUE) was declared at San Onofre due to an earthquake felt on site (EAL HU1.1). The US Geological Survey indicates that there was a 5.3 magnitude earthquake near Brawley California, about 125 miles southeast of the plant. There were no indication of any impact to site operations other than being felt by personnel. Equipment inspections and walkdowns are in progress. The licensee has notified state and local authorities. The NRC Resident Inspector will be notified. Notified other FEDS (FEMA, DHS, DHS NICC and Nuclear SSA via email).

• * * UPDATE FROM BAYER TO HUFFMAN AT 1713 EDT ON 8/26/12 * * *

On August 26, 2012 at 1346 PDT, San Onofre exited the Unusual Event based on an earthquake felt on site. Shortly after exiting the UE, the licensee felt more shaking in the control room. The licensee confirmed with the US Geological Survey that there has been an aftershock. The aftershock was approximately the same magnitude (5.4) and location as the original earthquake (about 125 southeast of the site). The licensee declared another unusual event at 1403 PDT. The licensee will re-perform all equipment walkdowns and inspections. The NRC Resident Inspector has been notified and is reporting to the site. R4DO (Hay), NRR EO (Lubinski), and IRD (Gott) notified.

• * * UPDATE AT 2352 EDT ON 8/26/2012 FROM ADAM BOW TO MARK ABRAMOVITZ * * *

Exited the NOUE HU1.1 - Earthquake at 2017 PDT on 8/26/12. The licensee will notify the NRC Resident Inspector. Notified the R4DO (Hay), NRR (Lubinski), IRD (Gott), DHS, FEMA, and DHS NICC.

On January 31, 2012, Unit 3 was shut down due to detection of a tube leak in one Steam Generator (SG). The shutdown was previously reported on Event Notification # 47628. Southern California Edison (SCE) has been performing in-situ pressure testing with non-radioactive water on tubes with significant wear indications. On March 14, 2012, at approximately 1120 PDT, Unit 3 Steam Generator (SG) E088 Tube R106 C78 did not meet the target performance criteria because leakage exceeded 0.5 gallons per minute at the maximum pressure achieved during the test (2,884 psig). This was the leaking tube that resulted in the Unit 3 shutdown. Subsequently, two additional tubes in Unit 3 SG E088 did not meet the target performance criteria as follows: at 1249 PDT, Tube R102 C78 exceeded 0.5 gallons per minute at 3,268 psig and at 1425 PDT, Tube R104 C78 exceeded 0.5 gallons per minute at 3,180 psig. These occurrences are reportable as an 8-hour notification to the NRC in accordance with 10 CFR 50.72(b)(3)(ii)(A). Testing and inspection of Unit 3 steam generator tubes is ongoing to determine the extent and cause of the observed wear. A follow-up notification will be made for additional in-situ pressure test failures. The extent and cause of the condition will be addressed in the follow-up licensee event report that will be submitted in accordance with 10 CFR 50.73(a)(2)(ii)(A). Defective tubes will be removed from service as required prior to Unit 3 plant startup. Unit 2 has been shut down since January 9, 2012 for a scheduled refueling outage. SCE previously performed in-situ pressure testing of the tube with the most wear in Unit 2. Results from this test demonstrated that the tube met the target performance criteria. The NRC Resident Inspector has been notified of this event.

• * * UPDATE FROM LEE KELLY TO DONALD NORWOOD AT 2108 EDT ON 3/15/2012 * * *

In-situ pressure testing on Unit 3 steam generator tubes was started on March 14, 2012 and is ongoing. On March 15, 2012, four additional tubes in Unit 3 SG E088 did not meet the target performance criteria of three-times normal pressure conditions as follows: (1) At 1109 PDT, Tube R100 C80 failed at 4,739 psig; (2) at 1437 PDT, Tube R107 C77 failed at 5,160 psig; (3) at 1604 PDT, Tube R101 C81 failed at 4,889 psig; and (4) at 1734 PDT, Tube R98 C80 failed at 4,886 psig. Testing and inspection of Unit 3 steam generator tubes is ongoing to determine the extent and cause of the observed wear. Follow-up notifications will be made for any additional in-situ pressure test failures." The licensee notified the NRC Resident Inspector. Notified R4DO (Cain).

• * * UPDATE FROM LEE KELLY TO JOHN SHOEMAKER AT 2115 EDT ON 3/16/12 * * *

In-situ pressure testing on Unit 3 steam generator tubes was started on March 14, 2012 and is ongoing. On March 16, 2012, one additional tube in Unit 3 SG E088 did not meet the target performance criteria of three-times normal pressure conditions as follows: at 1216 PDT, Tube R99 C81 failed at 5,026 psig. Testing and inspection of Unit 3 steam generator tubes is ongoing to determine the extent and cause of the observed wear. Follow-up notifications will be made for any additional in-situ pressure test failures. The licensee notified the NRC Resident Inspector. Notified R4DO (Cain).

On November 1, 2011 at 1450 PDT, San Onofre Unit 3 declared an ALERT and entered EAL HA3.1 due to an ammonia leak that prevented access to local areas. The plant is in a stable condition while the leakage is being secured. The turbine building on Unit 3 has been evacuated. Plant personnel are in the process of verifying no presence of ammonia in the turbine building. There was no impact on Unit 2.

• * * UPDATE FROM KEN HOUSEMAN TO JOHN KNOKE AT 2115 EDT ON 11/01/11 * * *

At 1807 PDT licensee exited the ALERT and EAL HA3.1. The leak was at the Ammonia day tank and was flowing through an overflow vent into the berm. The high level in the Ammonia day tank was due to a leaking closed valve between the Demineralizer system and the ammonia bulk storage. The berm area was drained of all fluids. The wind direction caused the ammonia fumes to travel to the Unit 3 turbine deck. No off-site HAZMAT personnel came on-site. At 1756 PDT the precautionary evacuation of on-site personnel was terminated. Unit 2 was not affected from this event. The NRC Resident Inspector was notified. Notified NRR EO (Fredrick Brown), R4DO (Vincent Gaddy, IRDMOC (Jeff Grant), DHS (Hill), DOE (Doyle), USDA (Krauf), FEMA (Fuller) and HHS (Fajardo).

• * * UPDATE FROM LEE KELLY TO VINCE KLCO AT 2228 EDT ON 11/01/11 * * *

On November 1, 2011, Southern California Edison notified the California Emergency Management Agency at 1755 PDT and the San Diego Department of Environmental Health at 1810 PDT that approximately 25 gallons of Ammonium Hydroxide was spilled under the Ammonium Hydroxide day tank located outside the Unit 3 turbine building. The spill was contained in a berm under the tank and subsequently cleaned up. Both Units 2 and 3 were at approximately 100% power at the time of the event. Notified the R4DO (Gaddy).

On November 4, 2010, at approximately 1504 PDT, San Onofre Nuclear Generating Station (SONGS) was notified that scrap circuit breakers salvaged from the SONGS warehouse had alarmed a portal radiation monitor at a metal recycling facility in Los Angeles County. The monitor indicated a reading approximately 40% above background levels. Naturally occurring isotopes in the circuit breakers are suspected to have alarmed the portal monitor. The metal recycling vendor (Alpert and Alpert) called the Los Angeles branch of the California Department of Health Services, Radiologic Health Branch to obtain a special permit authorizing the return shipment to SCE. SCE is reporting this event in accordance with 10CFR50.72(b)(2)(xi). At the time of this report, Unit 2 was operating at 100% power and Unit 3 is defueled. The licensee notified the NRC Resident Inspector.

• * * UPDATE AT 0018 EDT ON 11/06/10 FROM SIMMON TO HUFFMAN * *

On November 5, 2010, employees of the San Onofre staff disassembled the scrap circuit breakers that had been sent from the San Onofre Warehouse to the Alpert and Alpert salvage yard on November 4. These high voltage circuit breakers contain arc chutes consisting of large ceramic plates that contain naturally occurring radioactive material. All ceramic materials were removed. Health Physics technicians then re-surveyed the circuit breaker casings by direct and indirect survey and verified that they did not contain any detectable levels of radioactive material. Indirect survey of the ceramic material demonstrated that they had no detectable levels of removable radioactive material. The California Department of Health Services, Radiologic Health Branch will be notified of these results. The licensee has notified the NRC Resident Inspector. R4DO (Howell) and FSME (Chang) notified.

On August 16, 2010, at about 0100 PDT, SONGS Unit 2 Train 'A' Emergency Diesel Generator (EDG) 2G002 was removed from service for planned maintenance. Train 'A' EDG is the Appendix R protected Train. At about 1545 the same day, Southern California Edison (SCE) discovered a potential wiring discrepancy in the electronic governor. At 0300 on August 17, 2010, SCE determined two wires on a fire isolation fuse were confirmed to be terminated differently than specified in plant drawings and that the discrepancy would prevent the fuse and associated fire isolation switch from performing its Appendix R fire isolation function for the Train 'A' EDG. In accordance with NUREG-1022, Rev. 2, SCE is reporting this occurrence in accordance 10CFR50.72(b)(3)(ii)(B). While the incorrect wiring impacted the Appendix R qualifications of the Train 'A' EDG, it did not impact its other design functions and the EDG was capable to fulfill its safety function for all other Design Basis Events. Therefore, SCE considers the safety significance of the condition to be minimal. In accordance with LCS specification 3.7.113.1 Condition A, SCE will implement hourly Fire Watches for the impacted plant areas until such time that the wiring on the Unit 3 Train 'A' Emergency Diesel Generator 3G002 is conformed to be correct or has taken actions to correct any wiring discrepancy. An evaluation will be conducted to determine the cause of this condition. At the time of this occurrence, Unit 2 and Unit 3 were both at 100% power." The NRC Resident Inspector will be notified of this occurrence and will be provided with a copy of this report.

• * * RETRACTION FROM KELMENSON TO KLCO ON 9/14/10 @ 1528 (EDT)* * *

The licensee is retracting the event based on the following: Upon further investigation, SCE determined the suspected wiring discrepancy was only an issue with an elementary diagram that was used for circuit verification. SCE had already flagged this elementary diagram as requiring revision and a change to the diagram was pending and had not been released to the field. The fire isolation fuse was wired correctly." Consequently, SCE is retracting the 8-Hour Telephone Notification made to the NRC on August 17, 2010 (Event Log No. 46182)." The NRC Resident Inspector will be notified of and will be provided with a copy of this retraction. Notified the R4DO (Clark)

On January 18, 2010, at about 1950 PST, the access road to the SONGS MESA facilities became flooded after a day of rain. The San Onofre Emergency Operations Facility (EOF) is located at the MESA and because of the flooding, is inaccessible to passenger vehicles. While the EOF itself is operable, in the event of an emergency at San Onofre, SCE (Southern California Edison) would direct EOF emergency responders to the alternate EOF located in Irvine, California. SCE is reporting this occurrence to the NRC in accordance with 10CFR50.72(b)(3)(xiii). At the time of this occurrence, Unit 2 was shutdown for a Steam Generator Replacement outage and Unit 3 was operating at about 100% power. SCE will notify the NRC Resident Inspectors about this occurrence and will provide them with a copy of this report.

• * * UPDATE FROM GEOFF COOK TO DONG PARK @ 1208 EST ON 01/19/10 * * *

On January 18, 2010 at about 2101 PST, the MESA road flooding had dissipated sufficiently for car traffic to be passable. In the event of an emergency at San Onofre, there is no longer a need to redirect emergency responders to the alternate EOF located in Irvine, California. This report is to advise the NRC of this change in EOF access status. Also note that it is expected that rain will continue in the SONGS area during the week of January 17, 2010 and this status is subject to change. At the time of this occurrence, Unit 2 was shutdown for a Steam Generator Replacement Outage and Unit 3 was operating at about 100% power. SCE will notify the NRC Resident Inspectors about this occurrence and will provide them with a copy of this report. Notified R4DO (Werner) and NSIR (Kahler).

• * * UPDATE FROM GEOFF COOK TO PETE SNYDER @ 1232 EST ON 01/21/10 * * *

On January 20, 2009, at about 2107 PST, the access road to the SONGS MESA facilities again became flooded after a day of rain (reference NRC Operations Log Number 45634). The San Onofre Emergency Operations Facility (EOF) is located at the MESA and because of the flooding, is inaccessible to passenger vehicles. While the EOF itself is operable, in the event of an Emergency at San Onofre, SCE would direct EOF emergency responders to the alternate EOF located in Irvine California. SCE is reporting this occurrence to the NRC in accordance with 10CFR50.72(b)(3)(xiii). At the time of this occurrence, Unit 2 was in a Steam Generator Replacement Outage and Unit 3 was operating at about 100% power. SCE will notify the NRC resident inspectors about this occurrence and will provide them with a copy of this report." Notified R4DO (Werner) and NSIR/EP.