ENS Event | |
|---|---|
15:40 Mar 25, 2008 | |
| Title | Plant Shutdown Initiated Due to Degraded Battery Voltage |
| Event Description | On March 25, 2008 at approximately 0640 PDT, SCE discovered a battery with voltage slightly below Technical Specification limits. At approximately 0840 PDT, plant operators began cooling Moisture Separator Reheaters (MSR) in preparation for a Shutdown as required by TS 3.8.4. Initiating MSR cooldown reduced reactor power by 0.1%. Although plant operators had not initiated boration or control rod insertion, SCE is, nevertheless, reporting this occurrence in accordance with 10CFR50.72(b)(2)(i).
At approximately 0850 PDT, the battery was restored to Operable status and MSR cooldown was suspended. At approximately 1112 PDT, the Unit was returned to full power. SCE is continuing to assess if additional actions are required. At the time the shutdown was initiated, Unit 2 was operating at about 100% power. Unit 3 continues to operate at about 100% power. The NRC Resident Inspectors have been briefed on the shutdown plans and will be provided with a copy of this report. Preliminary information indicates that the degraded voltage was due to loose terminal bolts. |
| Where | |
|---|---|
San Onofre  California (NRC Region 4) | |
| Reporting | |
| 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | |
| Time - Person (Reporting Time:+-0.23 h-0.00958 days <br />-0.00137 weeks <br />-3.15054e-4 months <br />) | |
| Opened: | Susan Gardner 15:26 Mar 25, 2008 |
| NRC Officer: | Bill Huffman |
| Last Updated: | Mar 25, 2008 |
| 44092 - NRC Website
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Unit 2 | |
|---|---|
| Reactor critical | Critical |
| Scram | No |
| Before | Power Operation (100 %) |
| After | Power Operation (100 %) |
WEEKMONTHYEARENS 455642009-12-12T09:26:00012 December 2009 09:26:00
[Table view]10 CFR 50.72(b)(3)(v)(A), Loss of Safety Function - Shutdown the Reactor, 10 CFR 50.72(a)(1)(i), Emergency Class Declaration, 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unusual Event Declared Due to Both Emergency Diesel Generators Being Inoperable ENS 444562008-09-01T17:35:0001 September 2008 17:35:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Shutdown Due to Emergency Diesel Generator Shorting Ring Cracks ENS 440922008-03-25T15:40:00025 March 2008 15:40:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Plant Shutdown Initiated Due to Degraded Battery Voltage ENS 424512006-03-29T08:01:00029 March 2006 08:01:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Unit 3 Shutdown Due to Potential Safety Injection Tank Gasket Issue ENS 414102005-02-15T05:55:00015 February 2005 05:55:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Tech Spec Required Shutdown ENS 403962003-12-17T11:15:00017 December 2003 11:15:00 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown Technical Specification Required Shutdown Due to Loss of Both Trains of Safety Injection 2009-12-12T09:26:00 | |