05000278/LER-2018-001, Reactor Core Isolation Cooling System Pressure Switch Failure Results in Condition Prohibited by TS
| ML18172A260 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 06/21/2018 |
| From: | Pat Navin Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CCN: 18-60 LER 2018-001-00 | |
| Download: ML18172A260 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(ii) 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)(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)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 2782018001R00 - NRC Website | |
text
Exelon Generation CCN: 18-60 June 21, 2018 U. S. Nuclear Regulatory Commission A TIN: Document Control Desk Washington, DC 20555-0001
Subject:
Peach Bottom Atomic Power Station (PBAPS) Unit 3 Renewed Facility Operating License No. DPR-56 NRC Docket No. 50-278 Licensee Event Report (LER) 3-18-001 10CFR 50.73 Enclosed is a Licensee Event Report concerning a condition prohibited by Technical Specifications. In accordance with NEI 99-04, the regulatory commitment contained in this correspondence is to restore compliance with the regulations. The specific methods that have been planned to restore and maintain compliance are discussed in the LER. If you have any questions or require additional information, please do not hesitate to contact Jim Kovalchick at 717-456-3351.
Patrick D. Navin Site Vice President Peach Bottom Atomic Power Station PDN/dnd/I R 4129583 Enclosure cc:
US NRC, Administrator, Region I US NRC, Senior Resident Inspector R. R. Janati, Commonwealth of Pennsylvania S. Gray, State of Maryland B. Watkins, PSE&G, Financial Controls and Co-Owner Affairs
NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 (04*2018)
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LICENSEE EVENT REPORT (LEA)
Repo~ed lessons learned are ilcorporaled inlo tie licensing process and led back lo induslry. Send comments regarding burden eslimale lo lhe lntonnalion Services Branch l~\\
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If a means used lo inpose an inlormalion ccllection does not
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- 4. Title Reactor Core Isolation Cooling System Pressure Switch Failure Results in Condition Prohibited by TS
- 5. Event Date
- 6. LER 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 05000 Facility Name Docket Number 04 22 2018 2018 - 001 0
06 21 2018 05000
- 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 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 001 REV NO.
0 it occurred before 4/8/18, which would have resulted in the RCIC system being inoperable for a period of time exceeding the TS 3.5.3 allowed completion time of 14 days.
As a result, this event is being reported in accordance with 1 O CFR 50.73(a)(2)(i)(B), as a condition prohibited by Technical Specifications. If the RCIC system is inoperable, TS 3.5.3 Condition A requires the system to be restored to an operable status within 14 days. There is not firm evidence for when the failure occurred, however, for the purposes of conservative reporting per 1 O CFR 50. 73, it is considered possible to have been greater than 14 days.
Cause of the Event
Further investigation determined the switch failed due to an electrical short within the switch. Water had entered the switch enclosure, which resulted in corrosion and degradation of the switch internals, causing the electrical short. A diaphragm normally isolates the switch from the instrument line that contains condensed steam from the RCIC turbine exhaust piping. A tear in the diaphragm resulted in a small amount of water entering the switch enclosure.
Discoloration of the interior of the metal switch enclosure indicated the water had been in the switch for a period of time. The moisture caused corrosion and degradation of the switch, which resulted in a short circuit, causing the switch to fail.
Maintenance practices for the switch were reviewed and were determined to be consistent with industry standards for this type of switch. In addition to the quarterly surveillance test, calibration of the switch is verified every 18 months. Calibration history was reviewed and the last time the switch was out of tolerance was in 2001. The switch was within normal tolerances with no adjustment necessary since that time. There were no adverse trends in the data reviewed.
Corrective Actions
The switch has been replaced. Maintenance performed for this type of switch is being evaluated to identify improvements that will identify this type of degradation. Additional corrective actions are documented in the corrective action program.
Previous Similar Occurrences No previous similar occurrences have been identified. Page _3_ of....!_