05000373/LER-2019-001, Turbine Stop Valve Limit Switch Failure Due to Lubricant Degradation
| ML19015A101 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 01/15/2019 |
| From: | Washko J Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA19-003 LER 2019-001-00 | |
| Download: ML19015A101 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(ii)(B), Unanalyzed Condition 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)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(A), Completion of TS Shutdown 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 3732019001R00 - NRC Website | |
text
Exelon Generation RA19-003 January 15, 2019 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 LaSalle County Station, Unit 1 Renewed Facility Operating License No. NPF-11 NRC Docket No. 50-373 LaSalle County Station 2601 North 21 51 Road Marseilles, IL 61341 815-415-2000 Telephone www.exeloncorp.com 10 CFR 50.73
Subject:
Licensee Event Report 2019-001-00, Turbine Stop Valve Limit Switch Failure due to Lubricant Degradation In accordance with 1 O CFR 50.73(a)(2)(i)(B), Exelon Generation Company, LLC (EGC) is submitting Licensee Event Report (LER) Number 2019-001-00 for LaSalle County Station, Unit 1.
There are no regulatory commitments in this letter. Should you have any questions concerning this report, please contact Ms. Dwi Murray, Regulatory Assurance Manager, at (815) 415-2800.
Respectfully, n(/1-,..;J~
Joh\\J~hko Plant Manager LaSalle County Station
Enclosure:
Licensee Event Report cc:
Regional Administrator-NRC Region Ill NRC Senior Resident Inspector-LaSalle County Station
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150*0104 EXPIRES: 03/31/2020 (04-2018)
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3.Page LaSalle County Station, Unit 1 05000373 1
OF 3
- 4. Title Turbine Stop Valve Limit Switch Failure due to Lubricant Degradation
- 5. Event Date
- 6. LEA Number
- 7. Report Date
- 8. Other Facilities Involved I
Sequential I Rev Facility Name Docket Number Month Day Year Year Number No.
Month Day Year NA NA Faciltty Name Docket Number 11 16 18 2019 -
001 00 01 15 19 NA NA
- 9. Operating Mode
- 11. This Report is Submitted Pursuant to the Requirements of 10 CFR §: (Check all that apply)
D 20.2201(b)
D 20.2203(a)(3)(i)
D 50. 73(a)(2)(ii)(A)
D 50. 73(a)(2)(viii)(A)
D 20.2201(d)
D 20.2203(a)(3)(ii)
D 50.73(a)(2)(ii)(B)
D 50. 73(a)(2)(viii)(B) 1 D 20.2203(a)(1)
D 20.2203(a)(4)
D 50.73(a)(2)(iii)
D 50.73(a)(2)(ix)(A)
D 20.2203(a)(2)(i)
D 50.36(c)( 1 )(i)(A)
D 50.73(a)(2)(iv)(A)
D 50.73(a)(2)(x)
- 10. Power Level D 20.2203(a)(2)(ii)
D 50.36(c)(1 )(ii)(A)
D 50.73(a)(2)(v)(A)
D 13.11(a)(4)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.11(a)(s)
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 13.77(a)(1) 100 D 20.2203(a)(2)(v)
D 50.73(a)(2)(i)(A)
D 50.73(a)(2)(v)(D)
D 73.77(a)(2)(i)
D 20.2203(a)(2)(vi)
~ 50.73(a)(2)(i)(B)
D 50.73(a)(2)(vii)
D 73.77(a)(2)(ii)
D 50.73(a)(2)(i)(C)
D Other (Specify in Abstract below or in SEQUENTIAL NUMBER 001 REV NO.
00 maintained due to the redundant channels remaining OPERABLE. There were no reportability thresholds applicable to this issue at the time of the event, and there was no loss of safety function.
Upon receipt of the failure analysis on November 16, 2018, the station identified that a past inoperability period existed from the first occurrence of switch malfunction that occurred on May 20, 2018 until corrective action was taken in response to the surveillance test failure on September 9, 2018 based on firm evidence of the cause of the malfunction. The inoperability period was greater than allowed by TS LCO 3.3.3.1 and 3.3.4.1, as indicated below. This event is reportable in accordance with 10 CFR 50.73(a){2){i){B) as a condition prohibited by the plant's TS.
LCO 3.3.1.1 requires that the RPS instrumentation for each function is OPERABLE, and Condition A applies to one or more required channels being inoperable requires that the channel or its associated trip system is placed in trip within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. In this case, the station had exceeded the completion time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, when the malfunctioning channel was found inoperable during September 2018 surveillance testing. In addition, LCO 3.3.1.1 Condition D was not entered for the Completion Time of Condition A not met.
LCO 3.3.4.1 requires that the end of cycle recirculation pump trip (EOC-RPT) instrumentation is OPERABLE, which includes two channels of TSV closure and turbine control valve (TCV) fast closure or Minimum Critical Power Ratio (MCPR) limits are applied.
The events for the May 2018 and September 2018 component failures of turbine stop valve (TSV) limit switch 1 C71-N006C did not meet the reporting thresholds in accordance with 10 CFR 50. 72 because firm evidence did not yet exist. There were no safety consequences associated with the events since there was no loss of safety function.
CORRECTIVE ACTIONS
Corrective actions taken in response to the conditions were:
A work order was completed to replace the component, and to restore the associated channel to OPERABLE.
A trend investigation was performed for the aggregate of RPS TSV limit switch heat-related issues, that included disposition of the 1 C71-N006C limit switch.
Options for limit switch replacement was presented to station management, which identified the availability of a different model limit switch having higher temperature capabilities to be installed in applications starting in 2019.
Performed component failure analysis at off-site testing facility.
The extent of this condition is the eight (four switches per unit) RPS limit switches (Namco model number EA740-80001) located within the Main Turbine Stop Valve limit switch enclosures.
PREVIOUS OCCURRENCES
Searches were performed of the LaSalle Corrective Action Program (CAP) database, operating experience records, and licensee event reports for the previous three years. No similar previous reportable events for LaSalle Station were identified for the system or failure mode. However, performance history of these limit switches has been documented in the CAP since 2004.
COMPONENT FAILIRE DATA Manufacturer: NAMCO Controls Corporation Device: Unit 1 Turbine Stop Valve limit switch (Model: EA740-80001)
Component ID: 1 C71-N006C, Unit 1 Turbine Stop Valve Position Switch (Cat. ID 0000037836)
Serial No. 1216AA423293 / 10007 Page _3_ of _3_