05000395/LER-1917-001, Regarding C Main Feedwater Failure to Trip Results in Loss of Emergency Feedwater Auto Start Actuation Signal
| ML17205A237 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 07/24/2017 |
| From: | Lippard G South Carolina Electric & Gas Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| CR-17-01611, RC-17-0083 LER 17-001-00 | |
| Download: ML17205A237 (5) | |
| 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) |
| 3951917001R00 - NRC Website | |
text
George A. Lippard Vice President, Nuclear Operations 803.345.4810 SCE&G July 24, 2017 A SCANA COMPANY Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555
Dear Sir / Madam:
Subject:
VIRGIL C. SUMMER NUCLEAR STATION (VCSNS), UNIT 1 DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 LICENSEE EVENT REPORT (LER 2017-001-00)
C Main Feedwater Failure to Trip Results in Loss of Emergency Feedwater Auto Start Actuation Signal Attached is Licensee Event Report (LER) 2017-001-00, for the Virgil C. Summer Nuclear Station. This report describes a loss of Emergency Feedwater Auto Start Actuation Signal as a result of the 'C Main Feedwater Pump (MFP) failing to trip when given a trip signal from the Main Control Board, Digital Control System, and the local trip pull handle. Upon discovery that the 'C' MFP would not trip, Technical Specification 3.3.2 Limiting Condition of Operability was entered due to having less than the minimum number of channels operable required for Motor Driven Emergency Feedwater Pump actuation per TS Table 3.3-3 Functional Unit 6.g. This report is submitted in accordance with 10 CFR 50.73(a)(2)(i)(B).
Should you have any questions, please call Mr. Bruce Thompson at (803) 931-5042.
Very truly yours, WHK/GAL/ts Attachment c:
K. B. Marsh S. A. Byrne J. B. Archie N. S. Cams S. M. Shealy W. M. Cherry C. Haney J. H. Hamilton S. A. Williams NRC Resident Inspector L. W. Harris Paulette Led better J. C. Mellette ICES Coordinator K. M. Sutton Marsh USA, Inc.
Maintenance Rule Engineer NSRC RTS (CR-17-01611)
File (818.07)
PRSF (RC-17-0083)
INPO Records Center V. C. Summer Nuclear Station
- P. 0. Box 88
- Jenkinsville, South Carolina
- 29065
- F (803) 941-9776
- www.sceg.com
NRC FORM 366 (04-2017)
^BRSSj, U.S. NUCLEAR REGULATORY COMMISSION 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 form http://www.nrc.aov/readina-rm/doc-collections/nureas/staff/sr1022/r3/)
APPROVED BY OMB: NO. 3150-0104 EXPIRES: 03/31/2020 the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.
- 1. FACILITY NAME VC SUMMER - UNIT 1
- 2. DOCKET NUMBER 05000 395
- 3. PAGE 1 OF
- 4. TITLE C MAIN FEED WATER PUMP FAILURE TO TRIP RESULTS IN LOSS OF EMERGENCY FEEDWATER AUTO START ACTUATION SIGNAL
- 5. EVENT DATE
- 6. LER NUMBER
- 7. REPORT DATE
- 8. OTHER FACILITIES INVOLVED SEQUENTIAL NUMBER REV NO.
MONTH FACILITY NAME DOCKET NUMBER 05000 04 07 2017 2017 001 00 07 24 2017 FACILITY NAME DOCKET NUMBER 05000
- 9. OPERATING MODE
- 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)
]
20.2201(b) 20.2203(a)(3)(i) 50.73(a)(2)(ii)(A) 50.73(a)(2)(viii)(A) 1
]
20.2201(d) 20.2203(a)(3)(H) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 1
]
20.2203(a)(1) l l 20.2203(a)(4) 50.73(a)(2)(iii) 50.73(a)(2)(ix)(A) 20.2203(a) (2)(i) 50.36(c)(1 )(i)(A) 50.73(a)(2)(iv)(A) 50.73(a)(2)(x)
- 10. POWER LEVEL
[] 20.2203(a)(2)(H) 50.36(c)(1 )(ii)(A) 50.73(a)(2)(v)(A) 73.71(a)(4)
]
20.2203(a)(2)(iii) 50.36(c)(2) 50.73(a)(2)(v)(B) 73.71(a)(5)
[ l 20.2203(a)(2)(iv) 50.46(a)(3)(H) 50.73(a)(2)(v)(C) 73.77(a)(1) 100 l l 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a) (2) (i) 20.2203(a)(2)(vi)
{7} 50.73(a)(2)(i)(B) 50.73(a) (2) (vii) 73.77(a)(2)(H) 50.73(a)(2)(i)(C)
OTHER Specify in Abstract below or in =
Action 19 states that with the number of OPERABLE channels one less than the Total Number of Channels, STARTUP and/or POWER OPERATION may proceed provided the following conditions are satisfied:
a. The inoperable channel is placed in the tripped condition within one hour.
b. The Minimum Channels OPERABLE requirement is met; however, the inoperable channel may be bypassed for up to two hours for surveillance testing of other channels per Specification 4.3.2.1.
When the electronic and manual trips were attempted on April 7, 2017, no indication was received that the MFP turbine had tripped (i.e. stop valve closure, speed reduction, local indicator lights). Because the trip system would not actuate, one of three channels for MFP trip under TS 3/4.3.2 was inoperable.
LCO for TS 3.3.2 was entered at 21:15 on April 7, 2017, requiring the operable channel be placed in the trip condition within an hour. At 22:09, 'C' MFP was secured and LCO for TS 3.3.2 was exited. Therefore, Action 19 under TS 3.3.2 was satisfied as 'C' MFP was able to be placed in the tripped condition by securing the Lube Oil Pumps that supplied high pressure oil to the stop valves ultimately satisfying Emergency Feedwater ESFAS instrumentation requirements.
An evaluation found that water intrusion into the 'C' MFP oil system resulted in the corrosion of its carbon steel components such that the Secondary Operating Cylinder and Pilot Valve were bound. This bound condition would not allow the steam inlet valves to close resulting in the inoperable ESFAS.
The past adverse condition leading to the Emergency Feedwater ESFAS instrumentation channel being inoperable was the inability of the 'C' MFP to trip as a result of the Secondary Operating Cylinder and associated Pilot Valve being corroded. Review of MFP oil samples, which are taken on a monthly basis, indicated that possible water contamination began November 12, 2016. Since there is no evidence suggesting that the trip signals would have changed state from November 12, 2016 to April 7, 2017, 'C' MFP input to the Emergency Feedwater Auto Start Signal was determined to be inoperable for that period of time.
3.0 SAFETY SIGNIFICANCE
This event has no impact on the Probabilistic Risk Analysis (PRA) model. The PRA model includes start signals for Emergency Feedwater from: Low Steam Generator Level, Manual, Load Sequencer, and Anticipated Transient Without SCRAM Mitigation System Actuation Circuitry (AMSAC). Loss of Feedwater is not modeled as a separate actuation.
4.0 PREVIOUS OCCURRENCE No previous occurrence within the last three years. U.S. NUCLEAR REGULATORY COMMISSION (04-2017)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form http://vwvw.nrc.gov/readina-rm/doc-collections/nuregs/staff/sr1022/r3/') Page 3
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