05000270/LER-2022-003, Manual Reactor Trip Due to Main Feedwater Control Valve Positioner Malfunction
| ML22111A361 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/21/2022 |
| From: | Snider S Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RA-22-0139 LER 2022-003-00 | |
| Download: ML22111A361 (6) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 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)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability 10 CFR 50.73(a)(2)(i) |
| 2702022003R00 - NRC Website | |
text
Steven M. Snider Vice President Oconee Nuclear Station Duke Energy ON01SC l 7800 Rochester Hwy Seneca, SC 29672 o. 864.873.3478 f: 864.873.5791 Steve.Snider@duke-energy.com RA-22-0139 April 21, 2022 10 CFR 50.73 Attn: Document Control Desk U. S. Nuclear Regulatory Commission 11555 Rockville Pike Rockville, MD 20852-2746 Duke Energy Carolinas, LLC Oconee Nuclear Station Unit 2 Docket Number: 50-270 Renewed Operating Licenses: DPR-49
Subject:
Licensee Event Report 270/2022-003, Revision 00 - Manual Reactor Trip due to Main Feedwater Control Valve Positioner Malfunction Licensee Event Report 270/2022-003, Revision 00, is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.
There are no regulatory commitments associated with this LER.
There are no unresolved corrective actions necessary to restore compliance with NRC requirements.
If there are questions, or further information is needed, contact Laura Boyce, Regulatory Affairs, at (864) 873-6774.
Sincerely, Steven M. Snider Vice President Oconee Nuclear Station Enclosure: Licensee Event Report 270/2022-003 Rev.00
RA-22-0139 April 21, 2022 Page 2 cc (w/Enclosure):
Ms. Laura Dudes, Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. Shawn Williams, Project Manager U.S. Nuclear Regulatory Commission 11555 Rockville Pike Mail Stop O-08B1A Rockville, MD 20852-2738 Mr. Jared Nadel NRC Senior Resident Inspector Oconee Nuclear Station
NRC FORM 366 (08-2020)
NRC FORM 366 (08-2020)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3150-0104 EXPIRES: 08/31/2023 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.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
- 1. Facility Name Oconee Nuclear Station Unit 2
- 2. Docket Number 0500000270
- 3. Page 1 OF 4
- 4. Title Manual Reactor Trip due to Main Feedwater Control Valve Positioner Malfunction
- 5. Event Date
- 6. LER Number
- 7. Report Date
- 8. Other Facilities Involved Month Day Year Year Sequential Number Rev No.
Month Day Year Facility Name NA Docket Number 05000 02 21 2022 2022 003 00 4
21 2022 Facility Name Docket Number NA 05000
- 9. Operating Mode 1
- 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) 20.2201(d) 20.2203(a)(3)(ii) 50.73(a)(2)(ii)(B) 50.73(a)(2)(viii)(B) 20.2203(a)(1) 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 68 20.2203(a)(2)(ii) 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) 20.2203(a)(2)(iv) 50.46(a)(3)(ii) 50.73(a)(2)(v)(C) 73.77(a)(1) 20.2203(a)(2)(v) 50.73(a)(2)(i)(A) 50.73(a)(2)(v)(D) 73.77(a)(2)(ii) 20.2203(a)(2)(vi) 50.73(a)(2)(i)(B) 50.73(a)(2)(vii) 73.77(a)(2)(iii) 50.73(a)(2)(i)(C)
Other (Specify in Abstract below or in CONTINUED CAUSAL FACTORS The cause of feedwater control valve 2FDW-32 to fail to control FDW flow was foreign material contamination of the valve positioner shuttle valve from original manufacture.
CORRECTIVE ACTIONS
Immediate:
- 1. Replaced 2FDW-32 valve positioner
- 1. Work with valve positioner manufacturer to identify and correct manufacturing source of foreign material contamination
- 2. Revise procedures to include additional cleanliness and pre-installation tests of valve positioner shuttle valves
- 3. Replace valve positioners on Unit 3 FDW main and startup control valves (3FDW-32, 3FDW-35, 3FDW-41, and 3FDW-44) during Spring 2022 refueling outage
- 4. Replace valve positioners on Unit 1 FDW main and startup control valves (1FDW-32, 1FDW-35, 1FDW-41, and 1FDW-44) during Fall 2022 refueling outage
SAFETY ANALYSIS
The ONS Unit 2 manual trip on February 21, 2022, was uncomplicated and had no impact on public health and safety.
Following the malfunction of valve positioner for 2FDW-32 and the manual reactor trip, the 2A and 2B MDEFW pumps automatically started as designed to restore SG levels. Operators followed procedures to execute an orderly plant shutdown. FDW flow was aligned to the SG through the FDW startup control valves to remove decay heat by discharging steam to the main condenser.
Additional defense-in-depth to ensure safe shutdown was available from the Unit 2 EFW System, EFW via cross connects from Units 1 or 3, Protected Service Water (PSW) System, the Standby Shutdown Facility (SSF), and portable FLEX equipment. No Emergency Core Cooling System (ECCS) or other automatic safety system actuations occurred in response to this event.
A post-trip review found no procedural or human performance issues with the operator response to the event. There were no maintenance or other safety significant activities being conducted on any important plant systems or equipment at the time of the trip. Therefore, it is concluded that the impact on core damage risk was very low, and the event had no impact on public health and safety.
CONTINUED
ADDITIONAL INFORMATION
A review of Duke Energys Corrective Action Program did not identify any Oconee LERs or events in the last 3 years that involved the same underlying concerns or reasons as this event.
This event is considered INPO IRIS Reportable. There were no releases of radioactive materials, radiation exposures or personnel injuries associated with this event.