L-2014-050, LER 13-003-00 for St. Lucie, Unit 1, Regarding Latent MV-08-3 Contactor Failure Results in Operation Prohibited by Tech Specs: Difference between revisions

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{{Adams
#REDIRECT [[05000335/LER-2013-003]]
| number = ML14057A453
| issue date = 02/17/2014
| title = LER 13-003-00 for St. Lucie, Unit 1, Regarding Latent MV-08-3 Contactor Failure Results in Operation Prohibited by Tech Specs
| author name = Jensen J
| author affiliation = Florida Power & Light Co
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000335
| license number =
| contact person =
| case reference number = L-2014-050
| document report number = LER 13-003-00
| document type = Letter, Licensee Event Report (LER)
| page count = 4
}}
 
=Text=
{{#Wiki_filter:0 FPL.February 17, 2014 L-2014-050 10 CFR 50.73 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Re: St. Lucie Unit I Docket No. 50-335 Reportable Event: 2013-003-00 Date of Event: December 20, 2013 .Latent MV-08-3 Contactor Failure Results in Operation Prohibited by Tech Specs The attached Licensee Event Report 2013-003-00 is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.Sincerely, JosephJn Site Vice President St. Lucie Plant JJ/KWF Attachment Florida Power & Ught Company 6501 S. Ocean Drive, Jensen Beach, FL 34957~gL NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 113112017 (02-2014)
Estimated burden per response to comply with this mandatory collection request: 80 hours, Reported lessons learned are incorporated into the licensing process and fed back to industry.Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (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
...." LICENSEE EVENT REPORT (LER) 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 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 St. Lucie Unit 1 05000335 1 OF 3 4. TITLE Latent MV-08-3 Contactor Failure Results in Operation Prohibited by Tech Specs 5. EVENT DATE 6. LER NUMBER 17. REPORT DATE 8. OTHER FACILITIES INVOLVED M DA YEA Y SEQUENTIALI REV IMONTH DAY YEAR FACILITY NAME DOCKET NUMBER MONTH IDAY YEAR YEA NUMBER NO..12 20 2013 2013- 003 -00 2 17 2014 FACILITY NAME NADOCKET NUMBER 9. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR§: (Check all that apply)0l 20.2201(b)
[I 20.2203(a)(3)(i)
El 50.73(a)(2)(i)(C)
El 50.73(a)(2)(vii) 1[ 20.2201(d)
El 20.2203(a)(3)(ii)
El 50.73(a)(2)(ii)(A)
El 50.73(a)(2)(viii)(A)
El 20.2203(a)(1)
El 20.2203(a)(4)
El 50.73(a)(2)(ii)(B)
E] 50.73(a)(2)(viii)(B)
El 20.2203(a)(2)(i)
El 50.36(c)(1)(i)(A)
[1 50.73(a)(2)(iii)
El 50.73(a)(2)(ix)(A)
: 10. POWER LEVEL [] 20.2203(a)(2)(ii)
El 50.36(c)(1)(ii)(A)
[1 50.73(a)(2)(iv)(A)
[E 50.73(a)(2)(x)
E- 20.2203(a)(2)(iii)
El 50.36(c)(2)
El 50.73(a)(2)(v)(A)
E] 73.71(a)(4)
E] 20.2203(a)(2)(iv)
El 50.46(a)(3)(ii) 0l 50.73(a)(2)(v)(B)
[E 73.71(a)(5) 100% El 20.2203(a)(2)(v)
[I 50.73(a)(2)(i)(A)
[I 50.73(a)(2)(v)(C)
El OTHER El 20.2203(a)(2)(vi)
Z 50.73(a)(2)(i)(B)
El 50,73(a)(2)(v)(D)
Specify in Abstract below or in NRC Form 366A 12. LICENSEE CONTACT FOR THIS LER NAME lTELEPHONE NUMBER (include Area Kenneth IN Frehafer -Licensing Engineer1 Code)7 72-4 67 -774 8 13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT CAUSE SYSTEM COMPONENT ACU- REPORTABLE C SYSTEM COMPONENT MANU REPORTABLE FACTURER TO EPIX I FACTURE TO EPIX X BA CNTR L200 Y 14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MONTH [DAY YEAR Ij YES (If yes, complete 15. EXPECTED SUBMISSION DATE) [ NO SUBMISSION DATE ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines)On December 20, 2013, MV-08-3, the iC steam driven auxiliary feedwater (AFW) pump trip and throttle valve, failed to stroke open from the Unit 1 Control Room during its post maintenance operational check. Troubleshooting revealed a stuck contact in an auxiliary switch for the motor line contactor prevented the valve from opening, and provided firm evidence that the 1C AFW pump was inoperable for longer than its allowed outage time and shutdown completion time.The auxiliary switch for the contactor was replaced, tested, and the 1C AFW pump returned to service.The short exposure window, along with the availability of the electric driven AFW pumps and manual recovery capability of the 1C AFW pump, resulted in this event having no significant impact on the health and safety of the public.NCR FORM 366 (02-2014)
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (02-2014)LICENSEE EVENT REPORT (LER)CONTINUATION SHEET 1. FACILITY NAME St. Lucie Unit 1 NARRATIVE Description of the Event On December 20, 2013, St. Lucie Unit 1 was in Mode 1 at 100% reactor power. At 0934 hours Operations declared the 1C steam driven auxiliary feedwater (AFW) pump[EIIS:BA:P]
inoperable and entered the 72 hour Technical Specification (TS) action statement to perform planned maintenance on its trip and throttle valve, MV-08-3[EIIS:BA:V]  
.Following the planned maintenance MV-08-3 failed to stroke open from the Unit 1 Control Room during its post maintenance operational check. After the first failed attempt, Operations reset the supply breaker for MV-08-3 and mechanically tripped and reset the linkage for MV-08-3. A second start was attempted, and MV-08-3 did not move. Subsequent troubleshooting determined the auxiliary switch Al that energizes the 72/0 [EIIS:BA:CNTR]
contactor coil, that is used to open MV-08-3, was failed. "The Al auxiliary.switch was replaced and the contactor retested satisfactory.
Following the successful post maintenance testing, Operations declared the 1C AFW pump operable on December 21, 2013, at 0323 hours.During the investigation of this event, Engineering determined that firm evidence existed such that the Al auxiliary switch failure (stuck open contact) occurred December 17, 2013, at 0120 hours during the performance of the previous routine 1C AFW code run. The total out of service hours for this latent failure plus discovery and repair time was 98 hours, exceeding the TS allowed outage time (AOT) and shutdown completion time of 84 hours.Cause The failure of the 1C AFW pump to start was due to a failure of the 72/0 contactor auxiliary switch Al. Troubleshooting determined that the contactor Al auxiliary switch block "i and 2" contact was found stuck open due to excessive friction.Normally, the Al contact is mechanically opened by the contactor only while MV-08-3 has an active signal to it to open. The Al contact closes by internal spring force when MV-08-3 no longer has an active open signal applied. An open Al contact for a de-energized 72/0 contactor would prevent the contactor from energizing and MV-08-3 from opening.The Al auxiliary contactor was replaced.Analysis of the Event This condition is reportable under 10 CFR 50.73(a) (2) (i) (B) as "Any operation or condition which was prohibited by the plant's Technical Specifications." As previously noted, the total out of service hours for this latent failure plus discovery and repair time was 98 hours, exceeding the TS AOT and shutdown completion time of 84 hours.The St. Lucie Unit 2 MV-08-3 contactor is not the same type of contactor as that used in Unit 1. The construction of the switch does not utilize a plastic housing that could rub against the switch internals.
The metal housing is more rigid and would tolerate the tighter clearances without rubbing. A corrective action was initiated to investigate the population of vital steam trestle valve contactors that is applicable for a detailed check of the auxiliary contacts during Preventative Maintenance.
NRC FORM 366A (02-2014)
NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (02-2014)LICENSEE EVENT REPORT (LER)CONTINUATION SHEET 1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGE Y SEQUENTIAL REVISION YEAR NUMBER NUMBER St. Lucie Unit 1 05000335 Page 3 of 3 2013 003 00 NARRATIVE Safety Significance The AFW System at St. Lucie supplies feedwater to the steam generators during transients when normal feedwater sources are not available and automatically initiates AFW flow upon receipt of an auxiliary feedwater actuation signal (AFAS)during applicable design bases accidents.
The AFW system consists of a condensate storage tank (CST), two motor-driven AFW pumps, one steam turbine-driven AFW pump, and manual, check, and motor operated valves'that provide for inventory flow to the steam generators.
The AFW system uses main steam to drive the AFW turbine driven pump.During the 98 hour time period that the 1C AFW pump would not respond automatically to an AFAS, both electric driven AFW pumps were operable.
Although the failed contactor auxiliary switch would have prevented the 1C AFW pump from responding automatically during an AFAS, the pump could be started by local operator action.Factoring the relatively short exposure window, the availability of redundant and diverse electric driven AFW pumps,, and the manual recovery capability of the steam driven AFW pump, this event had no significant impact on the health and safety of the public.Corrective Actions The following licensee-planned corrective actions were entered under the St. Lucie Corrective Action Program.1. The failed Al auxiliary contactor was replaced and tested.2. A Preventative Maintenance Change Request (PMCR) was initiated to evaluate a 36 month frequency inspection and testing of the Unit 1 and Unit 2 MOVs line starters located in the steam trestles.Failed Component(s)
Local Starter for MV-08-3, Limitorque Model N/L Similar Events None NRC FORM 366A (02-2014)}}

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