05000373/LER-2019-002, Turbine Stop Valve Limit Switch Failure Due to Insufficient Lubrication
| ML19178A209 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 06/27/2019 |
| From: | Hansett P Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA19-037 LER 2019-002-00 | |
| Download: ML19178A209 (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)(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)(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) |
| 3732019002R00 - NRC Website | |
text
Exelon Generation RA19-037 June 27, 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 " Road Marseilles, IL 61341 815-415-2000 Telephone www.exeloncorp.com 10 CFR 50.73
Subject:
Licensee Event Report 2019-002-00, Turbine Stop Valve Limit Switch Failure due to Lubricant Degradation In accordance with 10 CFR 50.73(a)(2)(i)(B), Exelon Generation Company, LLC (EGC) is submitting Licensee Event Report (LER) Number 2019-002-00 for LaSalle County Station, Unit 1.
There are no regulatory commitments in this letter. Should you have any questions concerning this report, please contact Mr. Daniel Mearhoff, Regulatory Assurance Manager, at (815) 415-2800.
Respectfully,
!%/
~;;:;;;;;;;;;;;:~
Phil Hansett 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 (04-2018)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 LICENSEE EVENT REPORT (LER)
(See Page 2 for required number of digits/characters for each block)
(See NUREG-1022, R.3 for instruction and guidance for completing this fonn http://www.nrc.gov/reading-rm/doc-collections/nureas/stall/sr1022/r3D Eslinaled, the NRC may not conduct or sponsor, and a oerson is not reouired lo resoond to. the illonnation coDection.
- 1. Facility Name LaSalle County Station, Unit 1
- 4. Title
- 2. Docket Number 05000373 Turbine Stop Valve Limit Switch Failure due to Insufficient Lubrication
- 5. Event Date
- 6. LER Number
- 7. Report Date 3.Page 1
OF 3
- 8. Other Facilities Involved Year I Sequential Number I Rev FacifttyName NA Docket Number Month Day Year No.
Month Day Year NA FacifttyName Docket Number 05 03 19 2019 002 00 06 27 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)
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 73.71(a)(4)
D 20.2203(a)(2)(iii)
D 50.36(c)(2)
D 50.73(a)(2)(v)(B)
D 73.71(a)(5)
D 20.2203(a)(2)(iv)
D 50.46(a)(3)(ii)
D 50.73(a)(2)(v)(C)
D 73.77(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 002 REV NO.
00 Upon receipt of the failure analysis on May 3, 2019, the station identified that a past inoperability period existed as far back as the last successful surveillance on the TSV-3 limit switch (1 C71-N006C) performed on December 15, 2018, until corrective action was taken in response to the surveillance test failure on March 24, 2019. 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 1 O 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 March 2019 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 TCV fast closure or Minimum Critical Power Ratio (MCPR) limits are applied.
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 long-term action to replace the affected population of limit switches [Namco model EA740] with a more heat tolerant model [Namco model EA700] was ongoing when the event occurred. The extent of this condition is the eight (four switches per unit)
RPS limit switches located within the Main TSV limit switch enclosures. Replacements of the affected limit switches on Unit 2 were complete. Replacements for Unit 1 limit switches are scheduled for the next scheduled refueling outage.
The removed limit switch was sent to an off-site testing facility to obtain a component failure analysis.
PREVIOUS OCCURRENCES
This condition is related to similar behavior noted on this model of limit switch (TSV-3) prior to its replacement on September 9, 2018. Previous experience with this model of limit switch [Namco EA740] resulted in station actions to begin replacement of this model of limit switch with a version [Namco EA700] that has a higher temperature lubrication tolerance.
Unit 1 LER 373-2019-001-00 During quarterly surveillances of TSV limit switch 1 C71-N006C, the component exhibited degraded performance on May 20, 2018 and a failure on September 9, 2018. The component was replaced; and subsequent component failure analysis determined the cause was attributed to degradation of the switch lubricant due to exposure from a high temperature environment, which established firm evidence that the sluggish performance exhibited in May 2018 was related to the failure in September 2018 and that a past inoperability condition existed. Immediate corrective actions were taken to replace the component and restore the associated channel to OPERABLE. Additional actions included performance of a causal investigation, identification of a new limit switch model that has greater heat tolerance, with a component replacement schedule starting in 2019.
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. 1817AA424680 Page _3_ of...1__