View source for 05000287/LER-2022-002, Automatic Actuation of Emergency Feedwater System Due to Malfunctioning Startup Feedwater Control Valve

{{Adams
| number = ML22182A501
| issue date = 07/01/2022
| title = Automatic Actuation of Emergency Feedwater System Due to Malfunctioning Startup Feedwater Control Valve
| author name = Snider S
| author affiliation = Duke Energy Carolinas, LLC
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000287
| license number = DPR-049
| contact person = 
| case reference number = RA-22-0215
| document report number = LER 2022-002-00
| document type = Letter, Licensee Event Report (LER)
| page count = 6
}}
{{LER
| Title = Automatic Actuation of Emergency Feedwater System Due to Malfunctioning Startup Feedwater Control Valve
| Plant = 
| Reporting criterion = 10 CFR 50.73(a)(2)(ii)(A), 10 CFR 50.73(a)(2)(viii)(A), 10 CFR 50.73(a)(2)(ii)(B), 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), 10 CFR 50.73(a)(2)(x), 10 CFR 50.73(a)(2)(v)(A), 10 CFR 50.73(a)(2)(v)(B), 10 CFR 50.73(a)(2)(v), 10 CFR 50.73(a)(2)(i)(A), 10 CFR 50.73(a)(2)(i)(B), 10 CFR 50.73(a)(2)(vii), 10 CFR 50.73(a)(2)(i)
| Power level = 
| Mode = 
| Docket = 05000287
| LER year = 2022
| LER number = 2
| LER revision = 0
| Event date = 
| Report date = 
| ENS = 
| abstract = 
}}

=text=
{{#Wiki_filter: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-22-0215

July 1, 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 287/2022-002, Revision 00 - Automatic Actuation of Emergency Feedwater System due to Malfunctioning Startup Feedwater Control Valve

Licensee Event Report 287/2022-002, 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 Sam Adams, Regulatory Affairs, at (864) 873-3348.

Sincerely,

Steven M. Snider Vice President Oconee Nuclear Station

Enclosure: Licensee Event Report 287-2022-002 Rev.00

RA-22-0215 July 1, 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 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO.3150-0104 EXPIRES: 08/31/2023 (08-2020)

Oconee Nuclear Station Unit 3 0500000287 I 1 OF4
: 4. Title Automatic Actuation of Emergency Feedwater System due to Malfunctioning Startup Feedwater Control Valve
: 5. Event Date 6. LER Number 7. Report Date 8. Other Facilities Involved Sequential Rev Facility Name Docket Number Month Day Year Year Number No. Month Day Year NA 05000 05 06 2022 2022 002 00 07 01 2022 Facility Name Docket Number NA 05000
: 9. Operating Mode 11. This Report is Submitted Pursuant to the Requirements of 10 CFR &sect;: (Check all that apply) 3 * * *
* 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) 181 50.73(a)(2)(iv)(A)
* 50.73(a)(2)(x)
: 10. Power Level * * *
* 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) 0 * * * *
 * * *
* 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 

Maintenance personnel investigated and identified that the E/P converter for 3FDW-44 had failed with an elevated zero condition and would not output less than ~67% output. The E/P was replaced, and proper operation was verified. Operations then transitioned back to Main FDW and continued RCS cooldown for the outage.

This event was reported to the NRC on May 7, 2022, in Event Notification (EN) number 55888, as an 8-hour notification under 10 CFR 50.72(b)(3)(iv)(A) - Specified System Actuation (EFW). The event is also reportable under 10 CFR 50.73(a)(2)(iv)(A) as an EFW system actuation.

Units 1 and 2 were not affected by this event.

CAUSAL FACTORS

The cause of this event was a manufacturing deficiency within the Moore I/P transducer resulting in a faulted E/P converter that prevented the 3FDW-44 SFCV from responding to automatic and manual demand inputs.

==CORRECTIVE ACTIONS==
Immediate:
: 1. Replaced 3FDW-44 E/P.
: 2. Sent failed I/P to the vendor for analysis.
: 3. Replaced TBV I/P transducers on all 3 Units with units manufactured by the vendor with Lessons Learned incorporated.
: 4. Replaced HPI I/P transducers on Unit 3 with units manufactured by the vendor with Lessons Learned incorporated.

Planned:
: 1. Replace FDW I/P transducers on Unit 1 with units manufactured by the vendor with Lessons Learned incorporated. (Note: Unit 2 and 3 replacements were completed in most recent outages for each unit.)
: 2. Replace HPI I/P transducers on all Units 1 and 2 with units manufactured by the vendor with Lessons Learned incorporated.
: 3. Evaluate alternatives to improve the reliability of the E/P units.

==SAFETY ANALYSIS==
Following the trip of the 3A MFW pump as described earlier, all three EFW pumps automatically started as designed to restore and maintain SG levels for heat removal. There was not a significant plant transient since the reactor had already entered Mode 3 in the process of a normal plant shutdown. Additional defense-in-depth to maintain safe shutdown was available from EFW via cross connect lines from Units 1 or 2, 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-event 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 of the defense in depth plant systems or equipment at the time of the event. 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.

==ADDITIONAL INFORMATION==
A review of Duke Energys Corrective Action Program identified 4 related Oconee LERs since 2013 that involved similar underlying concerns or reasons as this event. This review revealed three similar Duke Energy events that occurred at ONS on April 12, 2018, January 31, 2015, and October 24, 2013, wherein E/P converter failures occurred. These previous events were reported in LER 269/2018-001 (ML18165A145), LER 287/2015-001 (ML15098A472) and LER 287/2013-001 (ML13358A336). Additionally, in the summer of 2021, a trend of TBV E/P converter failures was identified. As a result of the TBV failures, the vendor discovered some workmanship concerns and established corrective actions to prevent recurrence. Also, because of the TBV failures, 3FDW-44 was identified to be within the extent of condition, and it was scheduled to be replaced during the May 2022 Unit 3 outage. The failure mode of the 3FDW-44 E/P is similar to one that was discovered during Oconees trend of TBV failures.

One corrective action identified in the 2015 report was a planned corrective action to modify the FCV controls with a more fault tolerant design. The modifications have been completed for the FCV E/Ps on all 3 Units. The SFCVs were not included in the scope of that action and thus do not have the redundant E/P controls design that the FCVs have. As such, the previous corrective action from the 2015 report could not have prevented the SFCV E/P failure documented in this LER. Corrective actions from the 2018 report, which also documented a cause of a failed I/P, did replace the I/Ps on the Unit 3 SFCVs, however due to the manufacturing deficiency noted in the cause of the 3FDW-44 failure documented in this LER, that action was not able to prevent recurrence.

This event is considered INPO IRIS Reportable. There were no releases of radioactive materials, radiation exposures or personnel injuries associated with this event.
}}

{{LER-Nav}}