05000266/LER-2011-001, Regarding Loss of Offsite Power to Unit 1 Safeguards Buses
| ML12031A069 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 01/25/2012 |
| From: | Meyer L Point Beach |
| To: | Region 3 Administrator |
| References | |
| NRC 2012-0005 LER 11-001-00 | |
| Download: ML12031A069 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(vi)(A) 10 CFR 50.73(a)(2)(i) 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(ii)(A), Seriously Degraded 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 10 CFR 50.73(a)(2)(viii)(B) 10 CFR 50.73(a)(2)(iii) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(iv)(A), System Actuation 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v)(A), Loss of Safety Function - Shutdown the Reactor 10 CFR 50.73(a)(2)(v)(B), Loss of Safety Function - Remove Residual Heat 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 2662011001R00 - NRC Website | |
text
January 25,2012 POINT BEACH NRC 2012-0005 10 CFR 50.73 Regional Administrator, Region Ill U. S. Nuclear Regulatory Commission 2443 Warrenville Road, Suite 210 Lisle, IL 60532-4352 Point Beach Nuclear Plant, Units 1 Dockets 50-266 Renewed License Nos. DPR-24 Licensee Event Re~ort 2661201 1-001 -00 Loss of Offsite Power to Unit 1 Safenuard Buses Enclosed is Licensee Event Report (LER) 2661201 1-001-00 for Point Beach Nuclear Plant (PBNP), Unit 1. Pursuant to 10 CFR 50.73(a)(2)(vi)(A), the event is reportable as an event or condition that resulted in manual or automatic actuation of the emergency diesel generators.
This submittal contains no new or revised regulatory commitments.
If you have questions or require additional information, please contact Mr. James Costedio at 9201755-7427.
Very truly yours, NextEra Energy Point Beach, LLC Larry Meyer Site Vice President Enclosure cc:
Administrator, Region Ill, USNRC Project Manager, Point Beach Nuclear Plant, USNRC Resident Inspector, Point Beach Nuclear Plant, USNRC PSCW NextEra Energy Point Beach, LLC, 6610 Nuclear Road, Two Rivers, WI 54241
NCR FORM 366 (10-2010)
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION (10-2010)
LICENSEE EVENT REPORT (LER)
I.
FACILITY NAME Point Beach Nuclear Plant Unit 1 APPROVED BY OMB: NO. 3150-0104 EXPIRES: lOM1/2013 Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />. Reported lessons learned are incorporated into the licensing process and fed back to industry. Send comments regarding burden estimate to the FOlAlPrivacy Section (T-5 F53), U.S. Nuclear Regulato Commission, Washington, DC 20555-0001, or by internet e-mall to ir%ocollects.resourse@nrc.gov, and 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 an information collection does not display a currently valid OMB control number, the NRC ma not conduct or sponsor, and a person is not required to respond to, the inkrmation collection.
- 2. DOCKET NUMBER 05000266
- 4. TITLE Loss of Offsite Power to Unit 1 Safeguards Buses
- 3. PAGE 1 of 3
- 8. OTHER FACILITIES INVOLVED
- 9. OPERATING MODE
- 10. POWER LEVEL 0%
FACILITY NAME NA FACILITY NAME NA
- 7. REPORT DATE
- 5. EVENT DATE
- 11. THlS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFRS: (Check all that apply)
- 20.2201(b)
[7 20.2203(a)(3)(i) 50.73(a)(2)(i)(C) 50.73(a)(2)(vii)
[7 20.2201(d)
[7 20.2203(a)(3)(ii)
[7 50.73(a)(2)(ii)(A) 50,73(a)(2)(viii)(A)
[7 20.2203(a)(I)
[7 20.2203(a)(4) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B)
[7 20.2203(a)(2)(i) 50.36(c)(l)(i)(A)
[7 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A)
[7 20.2203(a)(2)(ii) 50.36(c)(l)(ii)(A)
IXI 50.73(a)(2)(iv)(A)
[7 50.73(a)(2)(x)
- 20.2203(a)(2)(iii)
I7 50.36(~)(2) 50.73(a)(2)(v)(A) 73.71(a)(4)
- 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(B) 73.71(a)(5)
[7 20.2203(a)(2)(v) 50.73(a)(2)(i)(A)
[7 50.73(a)(2)(v)(C)
[7 OTHER I7 20.2203(a)(2)(vi)
[7 50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D)
Specify in Abstract below or in The 13.8 kV system supplies offsite power to the station via the 4.1 6 kV and 480 V systems. The 13.8 kV system is divided into three buses which are designated H-01, H-02 and H-03. The H-02 bus supplies Unit 1 and is normally served by high voltage station auxiliary transformer 1X-03. The H-02 bus supplies power to low voltage station auxiliary transformer 1X-04. Similarly, the H-03 bus supplies Unit 2 and is normally served by high voltage station auxiliary transformer 2X-03. The H-03 bus supplies power to the low voltage station auxiliary transformer 2X-04. The units can be interconnected to alternate supplies by arranging bus tie breakers to connect H-02 to H-01 and H-03 to H-01.
11 Safety Analysis
The failure of the circuit switcher occurred during switchyard realignment and resulted in a low voltage condition which started the four standby emergency diesel generators. However, the fault (a high resistance connection) did not cause a lockout of 1x03, the associated switchyard component. As a result, the automatic transfer to close in the redundant offsite power supply in the switchyard was not initiated, and the GO1 and GO3 emergency diesel generators proceeded to automatically load to the Unit 1 safety system buses once they had reached operating voltage and frequency.
An assessment confirmed that the redundant circuit for offsite power remained available. Offsite power was restored to the Unit 1 safeguards buses by synchronizing the running EDGs to the grid and closing the alternate feed from offsite power. Offsite power remained available to the affected unit from this redundant path, as well as from the opposite unit's low voltage station auxiliary transformer throughout the event.
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Corrective Actions
Station procedures have been revised to check local circuit switcher indicators for proper configuration prior to and following operation. Additional corrective actions associated with the PMs are being tracked to completion in the station's corrective action program.
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Similar Events
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Component Failure Data
- 1) Manufacturer Descri~tion Circuit Switcher Model Number Type GI 3 Gap, Center-Break