05000382/LER-2021-001, Control Room Air Filtration Equipment Failure Resulting in a Condition Prohibited by Technical Specification 3.7.6.1

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Control Room Air Filtration Equipment Failure Resulting in a Condition Prohibited by Technical Specification 3.7.6.1
ML21053A128
Person / Time
Site: Waterford Entergy icon.png
Issue date: 02/22/2021
From: Wood P
Entergy Operations
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
W3F1-2021-0020 LER 2021-001-00
Download: ML21053A128 (5)


LER-2021-001, Control Room Air Filtration Equipment Failure Resulting in a Condition Prohibited by Technical Specification 3.7.6.1
Event date:
Report date:
Reporting criterion: 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications
3822021001R00 - NRC Website

text

Entergy Operations, Inc.

17265 River Road Killona, LA 70057-3093 Tel 504-464-3786 Paul Wood Manager, Regulatory Assurance 10 CFR 50.73 W3F1-2021-0020 February 22, 2021 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Licensee Event Report (LER) 2021-001-00 Control Room Air Filtration Equipment Failure Resulting in a Condition Prohibited by Technical Specification 3.7.6.1 Waterford Steam Electric Station, Unit 3 (Waterford 3)

NRC Docket No. 50-382 Renewed Facility Operating License No. NPF-38 The enclosed report is being sent pursuant to 10 CFR 50.73.

This letter contains no new regulatory commitments.

Should you have any questions or require additional information, please contact Paul Wood, Regulatory Assurance Manager, at 504-464-3786.

Respectfully, Regulatory Assurance Manager PIW/jkb

Enclosure:

Waterford 3 Licensee Event Report 2021-001-00 cc:

NRC Region IV Regional Administrator NRC Senior Resident Inspector - Waterford 3 NRC Project Manager - Waterford 3 Paul Wood Digitally signed by Paul Wood Date: 2021.02.22 06:50:26 -06'00'

Enclosure W3F1-2021-0020 Waterford 3 Licensee Event Report 2021-001-00

Abstract

On December 25, 2020 at 0537, Waterford 3 Steam Electric Station Control Room operators observed HVC-213A (Control Room Emergency Air Filtration Unit (EFU) Train A recirculation damper) out of its normal position during a control board walk down. Control Room EFU Train A was declared inoperable. During the restoration of the system, HVC-205A (Control Room EFU Train A inlet damper) failed open. HVC-205A was repaired and Control Room EFU Train A was declared operable on December 29, 2020 at 0200. During the past operability review, firm evidence was discovered that the condition observed on December 25, 2020 would have affected the operability of Control Room EFU Train A starting on December 21, 2020 at 1732, when HVC-213A initially moved from its intermediate to open position as indicated on the plant computer. Therefore, the total time Control Room EFU Train A was inoperable was 7 days, 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 28 minutes, exceeding the Technical Specification 3.7.6.1 allowed outage time.

During as-found testing of the removed hydramotor from HVC-213A, the hydraulic pump/motor assembly seized causing excessive motor current. The hydramotor hydraulic pump/motor assembly was determined to be faulty.

Corrective action included restoring the system to operable status and revising the shiftly walkdown checklists to allow a means to detect these components being out of their normal position.

There were no consequences to the general safety of the public, nuclear safety, industrial safety or radiological safety. No radiological release occurred due to this event.

Plant Conditions

At the time of this event Waterford 3 Steam Electric Station (Waterford 3) was operating at 100% reactor power (Mode 1). There were no other structures, systems or components out of service that contributed to this event.

Event Description

On December 25, 2020 at 0537, while operating in Mode 1, at 100% power, Waterford 3 Control Room operators observed HVC-213A (Control Room Emergency Air Filtration (EFU) Train A recirculation damper) [VI, CDMP] out of its normal position during a control board walk down. Control Room EFU Train A was declared inoperable.

Maintenance was completed to repair HVC-213A. During the restoration of the system another damper, HVC-205A (Control Room EFU Train A inlet damper) [VI, CDMP], failed open. HVC-205A hydramotor was rebuilt and the damper function was restored on December 29, 2020 at 0200. Operations declared the Control Room EFU Train A operable. With the additional failure of HVC-205A, the total time that the unit was inoperable from time of discovery was 3 days 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> and 23 minutes. During the past operability review, firm evidence was discovered that the as-found condition on December 25, 2020 would have affected the operability of control room EFU train A starting on December 21, 2020 at 1732, when HVC-213A initially moved from its intermediate to open position. Therefore, the total time Control Room EFU Train A was inoperable was 7 days 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 28 minutes, exceeding the Technical Specification (TS) 3.7.6.1 allowed outage time.

On December 21, 2020 at 1732, HVC-213A had failed to the open position as indicated on plant computer trending; however, Operations did not notice this change in position until December 25, 2020. The HVC-213A position indication was not part of the normal shiftly walkdown requirements. Upon discovering HVC-213A in the OPEN position, Operations declared the Control Room EFU Train A unit inoperable (December 25, 2020 at 0537).

Waterford 3 Technical Specification 3.7.6.1 Control Room Emergency Air Filtration System requires the control room emergency filtration trains to be operable in Modes 1, 2, 3, 4, 5, and 6 or during load movements with or over irradiated fuel assembles. Action a. specifies with one control room emergency air filtration train inoperable for reasons others than ACTION b, restore the inoperable train to OPERABLE status within 7 days.

Mechanical Maintenance performed a visual inspection and verified HVC-213A was in the OPEN position.

Troubleshooting determined that the cause was a failed hydramotor actuator for HVC-213A. The hydramotor was rebuilt and the damper function was restored on December 20, 2020 at 1751. Upon removing the tagout for this work, HVC-205A failed to the OPEN position. This damper also affects the operability of the Control Room EFU Train A unit. As a result, the Control Room EFU Train A remained inoperable. HVC-205A hydramotor was rebuilt and the damper function was restored on December 29, 2020 at 0200. Operations declared the Control Room EFU Train A operable. With the additional failure of HVC-205A, the total time the unit was inoperable from time of discovery was 3 days 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> and 23 minutes (December 25, 2020 at 0537 through December 29, 2020 at 0200);

however, there is firm evidence that the as-found condition would have affected the operability of Control Room EFU Train A starting on December 21, 2020 at 1732 when HVC-213A initially went from its intermediate to open position. Therefore, the total time Control Room EFU Train A was inoperable was 7 days 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and 28 minutes (December 21, 2020 at 1732 thru December 29, 2020 at 0200), exceeding TS 3.7.6.1 allowed outage time.

This condition is being reported pursuant to 10 CFR 50.73(a)(2)(i)(B), any operation which was prohibited by the plant's Technical Specifications.

Safety Assessment

Page 3 of 3 (08-2020)

U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: 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/r3/)

3. LER NUMBER Waterford Steam Electric Station, Unit 3 05000-382 YEAR SEQUENTIAL NUMBER REV NO.

2021 001 00 The Control Room Emergency Air Filtration system is modeled in the Probabilistic Risk Assessment (PRA);

however, it has low safety significance. The emergency filtration function and flow paths are not modeled in the PRA and not required for success. This failure, therefore, has a very low safety significance. There were no actual consequences to general safety of the public, nuclear safety, industrial safety and radiological safety for this event.

Event Cause(s):

During as-found testing of the removed hydramotor from HVC-213A, the hydraulic pump/motor assembly seized causing excessive motor current. The hydramotor hydraulic pump/motor assembly was determined to be faulty.

This is an Asco/Emerson (formally ITT Barton) model NH-91 hydramotor unit [VI, CDMP]. There was no initial indication of the cause of failure for HVC-205A hydramotor unit. This is an Asco/Emerson (formally ITT Barton) model NH-92 hydramotor unit [VI, CDMP].

Corrective Actions

WF3 has completed the following corrective actions:

HVC-213A and HVC-205A hydramotor actuators were rebuilt, tested, and the system was restored to operable status HVC-213A and HVC-213B were added to shiftly walkdown checklists to provide a means to detect these components being out of their normal position WF3 is tracking the following corrective actions to completion in its corrective action program:

Complete HVC-213A and HVC-205A hydramotor vendor detailed failure analysis (in-progress)

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