05000266/LER-2012-003, Regarding 2B-04 Safeguards 480V Bus De-Energized
| ML12236A145 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 08/23/2012 |
| From: | Meyer L Point Beach |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| NRC 2012-0061 LER 12-003-00 | |
| Download: ML12236A145 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(viii)(A) 10 CFR 50.73(a)(2)(ix)(A) 10 CFR 50.73(a)(2)(x) |
| 2662012003R00 - NRC Website | |
text
ENERGY POINT August 23,2012 BEACH NRC 2012-0061 10 CFR 50.73 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Point Beach Nuclear Plant, Units 1 and 2 Dockets 50-266 and 50-301 Renewed License Nos. DPR-24 and DPR-27 Licensee Event Re~ort 2661201 2-003-00 2B-04 Safenuards 480V Bus De-Energized Enclosed is Licensee Event Report (LER) 26612012-003-00 for Point Beach Nuclear Plant, Units 1 and 2. NextEra Energy Point Beach, LLC is providing this LER regarding 26-04 safeguards 480V bus feeder breaker trip.
This submittal contains no new or revised regulatory commitments.
If you have questions or require additional information, please contact Mr. Jim Costedio at 9201755-7427.
Very truly yours, NextEra Energy Point Beach, LLC 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
~ ~ N R C FORM 366 U.S. NUCLEAR REGULATORY COMMISSION 1 APPROVED BY OMB: NO. 3150-0104 EXPIRES: 10/31/2013 (1 LICENSEE EVENT REPORT (LER)
I 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 11 licensing process and -fed back to industry. Send cominents regarding burden estimate to the FOINPrivacy Section (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by internet e-mail to infocollects.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 mav not conduct or sDonsor, and a person is not Point Beach Nuclear Plant I
05000266 I
1 of 3
- 4. TITLE 1 required to respond to, the information collection.
111. FACILITY NAME
- 12. DOCKET NUMBER
- 13. PAGE (12~-04 Safeguards 480V Bus De-Energized 11 I
50.73(a)(2)(vii) 50.73(a)(2)(viii)(A) 50,73(a)(2)(viii)(B)
[7 50.73(a)(2)(ix)(A)
I7 50.73(a)(2)(x) 73.71(a)(4) 73.71(a)(5)
OTHER Specify in Abstract below or in have been capable of performing its safety function. For the periods of time that the feeder breaker with the improper setting was installed in bus 2B-04, the operating conditions were Unit 1 in MODE 1 and Unit 2 in MODE 4, 5, 6, or Defueled.
The feeder breaker was placed in service with the improper setting on March 23, 201 1. A breaker with the correct setting was installed on June 7, 201 1. Between those dates NextEra determined that bus 2B-04 was inoperable for specific time periods. Technical Specification Limiting Conditions for Operation (LCOs) and associated Action Conditions (TSACs) for TS 3.8.9 Distribution System - Operating (TSAC 3.8.9 A and B),
TS 3.8.10 Distribution Systems - Shutdown (TSAC 3.8.10 A), andlor TS 3.5.3 ECCS - Shutdown (TSAC 3.5.3 A and B) were not met during specific time periods.
Analysis of Safety Significance During the time periods when bus 2B-04 may have been incapable of supplying its required loads for Unit 1, the operating loads and those loads expected to be started in response to a Unit 1 event, could have caused the incorrectly set feeder breaker to bus 2B-04 to trip open. The loss of bus 2B-04 may have an impact on Unit 1 risk due to the commonlshared loads normally powered by bus 2B-04, such as K-3B Service Air Compressor, P-32D and P-32E Service Water Pumps, P-38B Standby Steam Generator Feedwater Pump, K-2B Instrument Air Compressor, and the 0-08 Battery Charger. NextEra determined the event to be of very low safety significance for Unit 1. A review for Safety System Function Failures (SSFFs) for Unit 1 determined that there was no SSFF because redundant equipment remained in service during the event.
Unit 2 was in Modes 4, 5, 6, or defueled during this time period. A deterministic, defense-in-depth, shutdown safety assessment process was used to evaluate the significance of this issue. Time periods when bus 2B-04 was determined to be inoperable was used in the assessment. Based on the assessment, the issue was considered to be of very low safety significance for Unit 2. A review for SSFFs for Unit 2 determined that there was a SSFF because the improperly set bus 2B-04 supply breaker, in conjunction with a postulated MODE 4 LOCA, may have caused a simultaneous loss of low head injection and containment sump recirculation capability.
Corrective Actions
A feeder breaker with the proper overload setting was installed in electrical bus 2B-04.
A root cause evaluation was completed and corrective actions were developed to address organizational and programmatic issues.
Similar Events
None Failed Components None