On 06/14/2004 at 0741 PDT, with both units near full power, the offsite power grid [FK] connected to San Onofre experienced a system disturbance. Alarms [ALM] alerted control room Operators (utility, licensed) that grid frequency dipped below 59.7 Hz. The lowest frequency was a momentary dip to about 59.5 Hz. The grid returned to normal frequency bands within three minutes, remaining stable thereafter. Units 2 and 3 were otherwise unaffected by the grid disturbance.
Southern California Edison (SCE) declared offsite power inoperable per its operating procedures. NUREG 1022, Revision 2 indicates offsite power unavailability is reportable regardless of whether other electrical power systems are available. SCE reported this event to the NRC Operations Center (Log No. 40818) in accordance with 10 CFR 50.72(b)(3)(v)(D). This report is provided in accordance with 10 CFR 50.73(a)(2)(v)(D).
The grid disturbance was initiated by a failed insulator [INS] on a 230 kV transmission line outside Phoenix, AZ. The failed insulator caused a 230 kV transmission line to fall into a transmission tower and short circuit.
No corrective actions are required. As the diesel generators [DG] for both units were operable during this event, there was little safety significance to this event. SONGS Units 2 and 3 have not previously experienced loss of offsite power due to offsite grid disturbances.
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| 05000362/LER-2004-001 | Manual Reactor Trip Due to Sea Grass at Intake Structure | 10 CFR 50.73(a)(2)(iv)(A), System Actuation | | 05000362/LER-2004-002 | Station ManagerEDISON' San Onofre
An EDISON INTERNATIONALS Company
May 8, 2006
U.S. Nuclear Regulatory Commission
Document Control Desk
Washington, D.C. 20555-0001
Subject:DDocket Nos. 50-362
Licensee Event Report No. 2004-002-01
San Onofre Nuclear Generating Station, Unit 3
Reference: Raymond Waldo (SCE) letter to NRC Document Control Desk, "Licensee
Event Report No. 2004-002", dated August 9, 2004.
Dear Sir or Madam:
In the letter referenced above, SCE provided a Licensee Event Report (LER) in
accordance with 10CFR50.73(a)(2)(i)(B) to report violations of Technical Specifications
due to an incomplete post-maintenance calibration of Logarithmic Power Level-High
Channel "A". When this LER was first submitted, SCE's cause evaluation was in
progress. SCE is revising this LER to incorporate the updated findings from the cause
evaluation.
Any actions listed are intended to ensure continued compliance with existing
commitments as discussed in applicable licensing documents; this LER contains no new
commitments. If you require any additional information, please so advise.
Sincerely,
a-sLi
LER No. 3-2004-002-01
cc: B. S. Mallet NRC Regional Administrator, Region IV
C. C. Osterholtz, NRC Senior Resident Inspector, San Onofre Units 2 & 3
P.O. Box 128
San Clemente, CA 92674-0128
949-368-9263/PAX 89263
Fax 949-368-6183
breigdp@songs.sce.com
NRC FORM 366 U.S. NUCLEAR REGULATORY APPROVED BY OMB: NO. 3150-0104 EXPIRES: 06/30/2007
(7-2001) COMMISSION Estimated burden per response to comply with this mandatory information collection request: 50 hours.
Reported lessons learned are incorporated into the licensing process and fed back to industry. Send
comments regarding burden estimate to the Records Management Branch (T-6 E6), U.S. Nuclear
Regulatory Commission, Washington, DC 20555-0001, or by intemet e-mail to bis@nrc.gov, andLICENSEE EVENT REPORT (LER) to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202 (3150-0104), Office of
Management and Budget, Washington, DC 20503. If a means used to impose information collection(See reverse for required number of
digits/characters for each block)
does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a
person is not required to respond to, the information collection.
1. FACILITY NAME 2. DOCKET NUMBER 3. PAGE
San Onofre Nuclear Generating Station (SONGS) Unit 3 05000362 1 OF 3
4. TITLE
Incomplete post-maintenance calibration of Logarithmic Power Level-High Channel "A" results in Technical
Specification Violations. | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications | | 05000361/LER-2004-003 | | 10 CFR 50.73(a)(2)(v)(D), Loss of Safety Function - Mitigate the Consequences of an Accident |
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