05000324/LER-2009-001, Regarding High Pressure Coolant Injection (HPCI) System Inoperable Due to Water in the HPCI Turbine Casing
| ML090970279 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 03/29/2009 |
| From: | Wills E Progress Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BSEP 09-0033 LER 09-001-00 | |
| Download: ML090970279 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(viii)(A) 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 |
| 3242009001R00 - NRC Website | |
text
Progress Energy MAR 29 2009 SERIAL: BSEP 09-0033 10 CFR 50.73 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001
Subject:
Brunswick Steam Electric Plant, Unit No. 2 Docket No. 50-324/License No. DPR-62 Licensee Event Report 2-2009-001-Ladies and Gentlemen:
In accordance with the Code of Federal Regulations, Title 10, Part 50.73, Carolina Power
& Light Company, now doing business as Progress Energy Carolinas, Inc., submits the enclosed Licensee Event Report (LER). This report fulfills the requirement for a written report within sixty (60) days of a reportable occurrence.
Please refer any questions regarding this submittal to Mr. Gene Atkinson, Supervisor -
Licensing/Regulatory Programs, at (910) 457-2056.
Sincerely, Edward L. Wills, Jr.
Plant General Manager Brunswick Steam Electric Plant MAT/mat
Enclosure:
Licensee Event Report Progress Energy Carolinas, Inc.
Brunswick Nuclear Plant PO Box 10429 Southport, NC 28461
Document Control Desk BSEP 09-0033 / Page 2 cc (with enclosure):
U. S. Nuclear Regulatory Commission, Region II ATTN: Mr. Luis A. Reyes, Regional Administrator Sam Nunn Atlanta Federal Center 61 Forsyth Street, SW, Suite 23T85 Atlanta, GA 30303-8931 U. S. Nuclear Regulatory Commission ATTN: Mr. Philip B. O'Bryan, NRC Senior Resident Inspector 8470 River Road Southport, NC 28461-8869 U. S. Nuclear Regulatory Commission (Electronic Copy Only)
ATTN: Mrs. Farideh E. Saba (Mail Stop OWFN 8G9A) 11555 Rockville Pike Rockville, MD 20852-2738 Chair - North Carolina Utilities Commission P.O. Box 29510 Raleigh, NC 27626-0510
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2010 (9-2007)
, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 3. PAGE Brunswick Steam Electric Plant (BSEP), Unit 2 05000324 1 of 5
- 4. TITLE High Pressure Coolant Injection (HPCI) System Inoperable Due to Water in the HPCI Turbine Casing
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
I j
FACILITY NAME DOCKET NUMBER MONTH DAY YEAR YEAR NUMBER NO.
05000 FACILITY NAME DOCKET NUMBER 01 27 2009 2009 - 001 - 00 03 29 2009 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
[] 20.2201(b)
EU 20.2203(a)(3)(i)
EU 50.73(a)(2)(i)(C)
EU 50.73(a)(2)(vii)
[ U 20.2201(d)
EU 20.2203(a)(3)(ii)
EU 50.73(a)(2)(ii)(A)
EU 50.73(a)(2)(viii)(A)
U 20.2203(a)(1)
[I 20.2203(a)(4)
EU 50.73(a)(2)(ii)(B)
EU 50.73(a)(2)(viii)(B)
__ 20.2203(a)(2)(i)
EU 50.36(c)(1)(i)(A)
EU 50.73(a)(2)(iii)
EU 50.73(a)(2)(ix)(A)
- 10. POWER LEVEL U 20.2203(a)(2)(ii)
EU 50.36(c)(1)(ii)(A)
EU 50.73(a)(2)(iv)(A)
EU 50.73(a)(2)(x)
U 20.2203(a)(2)(iii)
EU 50.36(c)(2)
EU 50.73(a)(2)(v)(A)
U-73.71 (a)(4) 100 U 20.2203(a)(2)(iv)
[I 50.46(a)(3)(ii)
EU 50.73(a)(2)(v)(B)
EU 73.71(a)(5)
U 20.2203(a)(2)(v)
U 50.73(a)(2)(i)(A)
[U 50.73(a)(2)(v)(C)
EU OTHER U 20.2203(a)(2)(vi)
U 50.73(a)(2)(i)(B)
[
50.73(a)(2)(v)(D)
Specify in Abstract below or in condensate pump had failed, Operations personnel pursued establishment of the preferred alternate drain path from the barometric condenser (i.e., via a test connection downstream of the condensate pump) in accordance with section 5-3, "HPCI Vacuum Lvi Hi," of procedure 2APP-A-01, "Annunciator Procedure for Panel A-0." This alternate path was established at 1901 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.233305e-4 months <br />; however, the HPCI Vacuum Tank Level Hi alarm did not clear. At 2007 hours0.0232 days <br />0.558 hours <br />0.00332 weeks <br />7.636635e-4 months <br />, the HPCI Turbine Exhaust Line Drain Pot Level High alarm returned. At this point, the HPCI system was declared inoperable due to the high exhaust line drain pot level and the threat of system damage due to a potential turbine start with water inside the turbine casing.
The high drain pot level alarm cleared within one to two minutes, but returned at 2018 hours0.0234 days <br />0.561 hours <br />0.00334 weeks <br />7.67849e-4 months <br /> and would not clear.
Subsequently, at approximately 2140 hours0.0248 days <br />0.594 hours <br />0.00354 weeks <br />8.1427e-4 months <br />, a second alternate drain path from the barometric condenser vacuum tank was established through the barometric condenser drain collecting valve (i.e., 2-E41-V5003).
This path was successful in reducing condenser level and, at 2204 hours0.0255 days <br />0.612 hours <br />0.00364 weeks <br />8.38622e-4 months <br />, the HPCI Turbine Exhaust Line Drain Pot Level High annunciator cleared.
Troubleshooting activities determined that the failure of the HPCI barometric condenser condensate pump was due to worn motor brushes. The brushes were replaced and, following post-maintenance testing, the HPCI system was returned to service at 2050 hours0.0237 days <br />0.569 hours <br />0.00339 weeks <br />7.80025e-4 months <br /> on January 28, 2009.
Event Cause
There are two root causes associated with this event. The HPCI barometric condenser condensate pump failed because no Preventive Maintenance (PM) activities had been established for the pump and motor.
The difficulties in establishing an alternate drain path from the barometric condenser were a result of an incorrect annunciator response procedure.
The HPCI system was declared inoperable when the ability to control water level at or below the exhaust line drain pot level alarm was lost. Level control was originally challenged due to failure of the HPCI barometric condenser condensate pump, which resulted in the condenser and the vacuum tank filling with water. The pump failure was caused by wear of the motor brushes, which resulted in a loss of contact between the brushes and the collector ring. There were no PM activities to inspect or refurbish the condensate pump and motor.
Initial attempts to establish the primary alternate drain path from the barometric condenser were unsuccessful because procedure 2APP-A-01 was technically incorrect. The primary alternate drain path was through a test connection downstream of the HPCI barometric condenser condensate pump. The test connection consists of two globe-type isolation valves in series (i.e., 2-E41 -V 13 and 2-E41 -V 14).
However, between the condensate pump and the test connection is valve 2-E41-F058, which is a stop check valve with a spring-loaded disc requiring a differential pressure of approximately 5 psig to lift. System pressure was inadequate to actuate the disc in the spring-loaded stop check valve.
Safety Assessment
The safety significance of this event is considered minimal. The RCIC system, the ADS, the CS system, and the LPCI system were all operable during the time that HPCI was inoperable. Adequate core cooling was ensured by the operability of the redundant and diverse low pressure injection systems in conjunction with ADS. Additionally, the RCIC system would have automatically provided makeup at high reactor operating pressures.
Corrective Actions
The following corrective actions to prevent recurrence have been identified.
" PM activities will be established for the Unit land 2 HPCI system barometric condenser condensate pumps and motors and the Unit 1 and 2 RCIC system barometric condenser condensate pumps and motors. These PMs are currently scheduled to be established by May 15, 2009.
" Procedures 1 (2)APP-A-01 were revised to ensure proper alternate drain paths can be established in the event of failure of the HPCI system barometric condenser condensate pumps. These procedure revisions were completed on February 2, 2009.
" Procedures 1(2)APP-A-01 were revised to minimize sources of condensate to the HPCI system barometric condenser when the HPCI system is not running and a HPCI vacuum tank high level condition exists. These procedure revisions were completed on March 9, 2009, for Unit 1 and March 12, 2009, for Unit 2.
Additional corrective actions include the following.
" The'HPCI system was declared operable, following repair of the HPCI barometric condenser condensate pump, on January 28, 2009, at 2050 hours0.0237 days <br />0.569 hours <br />0.00339 weeks <br />7.80025e-4 months <br /> EST.
- The Unit 1 HPCI system barometric condenser condensate pump motor brushes will be inspected and any necessary repairs completed. This action is currently scheduled to be completed by June 30, 2009.
" The Unit 1 and Unit 2 RCIC system barometric condenser condensate pump motor brushes will be inspected and any necessary repairs completed. This action is currently scheduled to be completed by July 30, 2009.
" The PM requirements for other components needed to ensure HPCI condensate removal will be reviewed and any necessary changes implemented. This action is currently scheduled to be completed by June 15, 2009.
Previous Similar Events
A review of LERs and corrective action program condition reports for the past three years identified the following similar event.
e Nuclear Condition Report (NCR) 223820, "HPCI Overspeed Test Halted Due to Unexpected Annunciation," generated on February 27, 2007, documented a high vacuum tank alarm that occurred while performing procedure OPT-09.8, "HPCI System Coupled Overspeed Trip Test," on Unit 2. One of the apparent causes of this event was identified as minor degradation of the HPCI system barometric condenser condensate pump. The pump had been in service for many years and the potential for age-related degradation was identified. However, a subsequent review found that performance of the pump had been acceptable. As such, the PM activities for the pump were not questioned.
Additionally, during investigation of this event, it was discovered that valve 2-E41-F058 was a stop check valve versus a globe valve as shown on the Piping and Instrument Drawing and described in the Equipment Database. Activities to correct the condition were informal and failed to evaluate how the finding could impact operability of the system or to update applicable plant drawings.
These errors were individual human performance errors.
Based on the factors discussed above, the actions taken in response to NCR 223820 did not prevent the HPCI system inoperability discussed in LER 2-2009-001.
Commitments
No regulatory commitments are contained in this report.