On September 1, 2008, at about 1035 PDT, Southern
California Edison (
SCE) began a planned shutdown of San Onofre Unit 3. This shutdown is in anticipation of exceeding the Allowed Outage Time (
AOT) of 14 days of
Technical Specification 3.8.1 Action B.4 for an inoperable Diesel Generator (Train B). The
AOT is due to expire on September 2, 2008 at about 0200. If the system cannot be restored within the allowed outage time, a plant shutdown is required. The initiation of this shutdown is being reported in accordance with
10CFR50.72(b)(2)(i).
An inspection of the DG generator revealed cracks in the shorting ring, requiring replacement of the generator. Post maintenance testing performed after replacement revealed anomalous readings. SCE determined that problem identification, repair and post test could not be performed before expiration of the AOT. Consequently, shutdown has been initiated.
At the initiation of the shutdown, SONGS Unit 3 was operating at full power. SONGS Unit 2 is operating at approximately 99 percent power.
The NRC Resident Inspectors have been briefed on the shutdown plans and will be provided with a copy of this report.
