05000382/LER-2022-002, Operation Prohibited by Technical Specifications Due to Personnel Error
| ML22133A248 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 05/13/2022 |
| From: | Lewis J Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| W3F1-2022-0032 LER 2022-002-00 | |
| Download: ML22133A248 (7) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications 10 CFR 50.73(a)(2)(v), Loss of Safety Function |
| 3822022002R00 - NRC Website | |
text
- ) entergy W3F1-2022-0032 May 13, 2022 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 John Lewis Manager Regulatory Assurance 504-739-6028 10 CFR 50.73
Subject:
Licensee Event Report 50-382/2022-002-00, Operation Prohibited by Technical Specifications Due to Personnel Error Waterford Steam Electric Station, Unit 3 NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38 Entergy Operations, Inc. (Entergy) submits the enclosed Licensee Event Report (LER) 50-382/2022-002-00 for Waterford Steam Electric Station, Unit 3. This event is reportable in accordance with 1 O CFR 50.73(a)(2)(i)(B) as any operation or condition that was prohibited by the plant's technical specifications and 1 O CFR 50.73(a)(2)(v)(C) for an event or condition that could have prevented the fulfillment of a safety function. The LER describes a non-compliance with Technical Specification 3.7.7 due to personnel error.
This letter contains no new commitments.
Should you have any questions concerning this issue, please contact John D. Lewis, Manager, Regulatory Assurance, at 504-739-6028.
John D. Lewis JDUjkb Entergy Operations, Inc., 17625 River Road, Killona, LA 70057
W3F1-2022-0032 Page 2 of 2 Enclosure: Licensee Event Report 50-382/2022-002-00 cc:
NRG Region IV Regional Administrator NRG Senior Resident Inspector-Waterford Steam Electric Station, Unit 3 NRG Project Manager - Waterford Steam Electric Station, Unit 3 Louisiana Department of Environmental Quality
Enclosure to W3F1-2022-0032 Licensee Event Report 50-382/2022-002-00
Abstract
On March 17, 2022, at 2145 CT, while Waterford Steam Electric Station Unit 3 was operating in Mode 1, at 100%
power, it was discovered that the open limit switch for the Controlled Ventilation Area System (CVAS) Filter Train B inlet valve HVR-304B was set incorrectly. Technical Specification (TS) 3.7.7 requires two independent controlled ventilation area systems shall be operable in Modes 1, 2, 3, and 4. The TS action statement requires that with one controlled ventilation area system inoperable, restore the inoperable system to OPERABLE status within 7 days, or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. The CVAS Train B exceeded the allowed outage time required by TS 3.7.7 and there were instances where CVAS Train A was concurrently inoperable.
Technicians mistakenly adjusted the open limit switch instead of the intermediate limit switch while adjusting air flow/
differential pressure settings due to personnel error. Subsequently, the intermediate and open limit switches were both adjusted correctly for air flow/differential pressure and to allow HVR-304B to be adjusted fully open if desired.
This condition is being reported pursuant to 1 O CFR 50.73(a)(2)(i)(B) - any operation or condition that was prohibited by the plant's technical specifications and 10 CFR 50.73(a)(2)(v)(C) - an event or condition that could have prevented the fulfillment of a safety function.
PLANT STATUS SEQUENTIAL NUMBER 002 REV NO.
00 On March 17, 2022, at 2145 CT, Waterford Steam Electric Station, Unit 3 (Waterford 3) was operating at 100% power in Mode 1. There were no other structures, systems, or components that were inoperable at the time that contributed to the event.
EVENT DESCRIPTION
On March 17, 2022, while troubleshooting an issue with Controlled Ventilation Area System (CVAS) Filter Train B inlet valve HVR-304B [PDCV] open stroke time, technicians discovered that the HVR-304B open limit switch [ZIS] was set incorrectly. This resulted in CVAS [VF] Train B being inoperable. Waterford 3 Technical Specification (TS) 3.7.7 requires two independent controlled ventilation area systems shall be operable in Modes 1, 2, 3, and 4. The TS action statement requires that with one controlled ventilation area system inoperable, restore the inoperable system to OPERABLE status within 7 days, or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
The CVAS filter [FLT] train A inlet valve HVR-304A [PDCV] and CVAS filter Train B inlet valve HVR-304B are motor operated valves (MOVs) and each are controlled in the same manner. Each valve actuator is 480 Volt AC motor operated and fails as is upon loss of power. Upon starting the CVAS unit, the inlet valve is set to open partially to provide resistance to the system when the filters are clean. Over time as filters become loaded, the inlet valve must be opened further to maintain the same system resistance. This ensures the TS required air flow is maintained within the assumed values for filter efficiency calculations.
The HVR-304B limit switch was adjusted on July 26,.2021 to correct an air flow/differential pressure issue. The technicians incorrectly adjusted the open limit switch instead of the intermediate limit switch. This prevented the valve from being adjusted in the more open direction to compensate for higher filter resistance, as would be required during a design-basis accident. This resulted in the CVAS Train B being inoperable during the period following the incorrect limit switch adjustment on July 26, 2021, until the intermediate limit switch and open limit switches were both adjusted correctly on March 18, 2022 for air flow/differential pressure and to allow the valve to be adjusted fully open if desired.
CVAS Train B was inoperable for approximately 235 days. This period exceeds the allowed outage time required by TS 3.7.7.
Additionally, CVAS Train A was inoperable for planned maintenance on three instances during the period from July 26, 2021 until March 18, 2022. Both trains of CVAS were inoperable during this period for approximately 94 hours0.00109 days <br />0.0261 hours <br />1.554233e-4 weeks <br />3.5767e-5 months <br />. This resulted in both trains of CVAS being inoperable resulting in a condition that could have prevented the fulfillment of a safety function.
The CVAS is designed to provide high efficiency particulate filtration and iodine adsorption for air exhausted from the CVAS area following a design-basis loss of coolant accident (LOCA).
This event is being reported under 10 CFR 50.73(a)(2)(i)(B) and 10 CFR 50.73(a)(2)(v)(C) which requires submittal of a Licensee Event Report within 60 days after the discovery for any operation or condition that was prohibited by the plant's technical specifications and an event or condition that could have prevented fulfillment of the safety function at any time within 3 years of the date of discovery. Page 2 of 4 (08-2020)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 08/31/2023
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LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/r3/)
3, LEA NUMBER YEAR Waterford Steam Electric Station, Unit 3 05000-0382 2022 SEQUENTIAL NUMBER 002 REV NO.
00 The cause of the human performance error is that the Entergy maintenance technicians performing the limit switch adjustment on HVR-304B misread the controlled wiring diagram due to improper verification practices when identifying the proper limit switch to adjust. Additionally, the post-maintenance testing was inadequate in that it did not verify that HVR-304B would stroke fully open.
Timeline of Events 07/26/2021 -At 0330, CVAS Train B was declared inoperable to perform corrective maintenance to correct a low unit DP/ air flow. Technicians mistakenly adjusted the HVR-304B open limit switch but should have adjusted the intermediate limit switch. This resulted in HVR-304B opening to the proper intermediate position initially but would not have allowed further adjustments in the open direction if desired. The open limit switch stops the valve from traveling any further in the open direction. The functional test performed by maintenance technicians did not include sufficient clarity to ensure that HVR-304B can be throttled to its full open position after adjustments are made. Following the maintenance, CVAS Train B was declared operable.
03/17/22 - While troubleshooting the open stroke time issue with HVR-304B, technicians discovered that the HVR-304B open limit switch was set incorrectly at the intermediate setting. This discovery with the open limit switch set incorrectly had no effect on the HVR0 304B stroke time. The technicians noticed this error while inspecting the HVR-304B. A condition report (CR) and a work order were issued to correct the issue.
03/18/22 - The HVR-304B open and intermediate limit switches were both adjusted correctly for air flow/differential pressure and to allow the valve to be adjusted fully open if desired. CVAS Train B was declared operable at 2315 CT.
SAFETY ASSESSMENT
The actual consequences as stated in the problem statement were HVR-304B and CVAS Train B were not able to perform their specified safety functions. There were no other actual consequences to general safety of the public, nuclear safety, industrial safety, and radiological safety for this event.
The safety function of HVR-304B is specifically related to limiting post-accident dose. This valve does not contribute to prevention or mitigation of plant transients. As such, it has no quantifiable impact to Probabilistic Risk Assessment (PRA) metrics of core damage frequency or large early release frequency and can be considered as having negligible nuclear safety impact.
Immediate/interim/mitigating actions to reduce the frequency or consequence (pending implementation of final actions) are not needed since the risk if no action is taken is low. The impact to nuclear safety from the failure of this valve to modulate correctly is negligible.
Therefore, the potential consequence to general safety of the public, nuclear safety, industrial safety, and radiological safety of this event, even if the limit switch that was inappropriately adjusted is not considered, is negligible.
EVENT CAUSE(S)
The HVR-304B (CVAS B inlet valve) was adjusted on July 28, 2021 to correct an air flow/differential pressure issue.
The technicians incorrectly adjusted the open limit switch instead of the intermediate limit switch. This prevented the valve from being adjusted in the more open direction to compensate for hiqher filter resistance, as would be required Page 3 of 4 (08-2020)
U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 08/31/2023
(~)
LICENSEE EVENT REPORT (LER)
CONTINUATION SHEET (See NUREG-1022, R.3 for instruction and guidance for completing this form https://www.nrc.gov/reading-rm/doc-collections/nuregs/staff/sr1022/@
- 3. LEA NUMBER YEAR Waterford Steam Electric Station, Unit 3 05000-0382 2022 SEQUENTIAL NUMBER 002 during a design-basis LOCA. The post-maintenance testing was inadequate in that it did not verify that HVR-3048 would stroke fully open.
CORRECTIVE ACTIONS
REV NO.
00 HVR-3048 intermediate and open limit switches were both adjusted correctly for air flow/differential pressure and to allow the valve to be adjusted fully open if desired.
Technician behaviors were addressed in accordance with Entergy performance management procedures/programs.
Waterford 3 plans to implement the following additional corrective action.
Revise motor operated valves maintenance procedure ME-007-008 to ensure MOVs with three limit switches are tested at each of the three positions.
PREVIOUS SIMILAR EVENTS
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