2CAN092301, Reply to a Notice of Violation

Reply to a Notice of Violation

ML23251A100
Person / Time
Site:	Arkansas Nuclear
Issue date:	09/08/2023
From:	Keele R Entergy Operations
To:	NRC Region 4, Document Control Desk, Office of Nuclear Reactor Regulation
References
2CAN092301
Download: ML23251A100 (1)

Text

) entergy Riley D. Keele, Jr.

Manager Regulatory Assurance Arkansas Nuclear One Tel 479-858-7826 2CAN092301 10 CFR 2.201 September 8, 2023 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Reply to a Notice of Violation Arkansas Nuclear One, Unit 2 NRC Docket No. 50-368 Renewed Facility Operating License No. NPF-6

Reference:

NRC letter to Entergy, "Arkansas Nuclear One - Integrated Inspection Report 05000313/2023002 and 05000368/2023002 and Notice of Violation,"

(0CNA082301) (ML23221A301), dated August 11, 2023 By the reference above, the NRC issued Entergy Operations, Inc. (Entergy) a green Notice of Violation (NOV) for Arkansas Nuclear One, Unit 2 (ANO-2) for failure to promptly identify and correct a condition adverse to quality. Specifically, the licensee failed to correct in a timely manner the deficient system design of the check valves admitting steam to the emergency feedwater turbine. The NOV requires a written response within 30 days addressing the following: reason for the violation, corrective steps that have been taken and results achieved, corrective steps that will be taken, and date when full compliance will be achieved. Enclosure 1 provides Entergy's reply to the NOV.

The new commitments contained in this submittal are provided in Enclosure 2.

Should you have any questions, please contact Mr. Riley Keele at 479-858-7826.

f!:t~-

Respectfully, Entergy Operations, Inc. 1448 SR 333, Russellville, AR 72802

2CAN092301 Page 2 of 2

Enclosures:

1. Reply to a Notice of Violation

2. List of Regulatory Commitments cc: NRC Region IV Regional Administrator NRC Senior Resident Inspector - Arkansas Nuclear One NRC Project Manager - Arkansas Nuclear One R4Enforcement@nrc.gov

Enclosure 1 2CAN092301 Reply to a Notice of Violation

2CAN092301 Page 1 of 3 Reply to a Notice of Violation Description of Violation:

Failure to Establish Adequate Corrective Actions Resulting in Excessive Instances of Damaged and Broken Internals of the Emergency Feedwater Pump Turbine Steam Admission Check Valves Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green [H .6] - Design 71152A Systems NOV 05000368/2023002-03 Margins Open The inspectors identified a Unit 2 Green finding and associated Notice of Violation of 10 CFR Part 50, Appendix B, Criterion XVI , "Corrective Action ," for the failure to promptly identify and correct a condition adverse to quality. Specifically, the licensee failed to correct in a timely manner the deficient system design of the check valves admitting steam to the emergency feedwater turbine.

Entergy documented the violation in its Corrective Action Program and a causal analysis was performed to identify and correct the underlying causes for this failure.

Reason for the violation:

Arkansas Nuclear One, Unit 1 (ANO-1) and Unit 2 (ANO-2) were issued a Green Non-Cited Violation (NCV) in 2018 (NCV 05000313/2018011-02 and 05000368/20187011-02).

The inspectors identified a Green non-cited violation of 10 CFR Part 50, Appendix B, Criterion XVI, "Corrective Actions," was identified for failure to establish an adequate corrective action program and the resulting inability to correct a deficient system design which resulted in damaged and broken internals of the check valves admitting steam to the emergency feedwater pump turbine. Specifically, attempts to correct conditions adverse to quality were unsuccessful when the internals of the safety-related emergency feedwater steam admission check valves were found damaged or broken resulting in the system experiencing multiple and extended periods of degraded and nonconforming conditions.

In 2019, an Engineering Change was approved to change the previous check valve design to a new design check valve. This change was implemented for ANO-2 in 2020 during refueling outage 2R27. During each subsequent ANO-2 refueling outage, missing parts were discovered for the check valves as part of normally scheduled inspections.

In 2022, it was determined the missing parts issue was caused by vendor manufacturing deficiencies; specifically, failure to adequately stake the stem nut and failure to install both halves of a required washer. Due to these failures, ANO-2 has been unable to determine if the check valve design installed in 2020 has been satisfactory and the effectiveness review for this change remains indeterminate. During the check valve replacements in 2023, proper stem nut staking and assembly was verified. The inspections in Fall 2024 refueling outage (2R29) will be used to validate the assembly issues have been addressed.

As part of the causal evaluation performed for this Notice of Violation, a causal factor for the failure to reach an adequate solution to the original Non-Cited Violation was identified as a lack

2CAN092301 Page 2 of 3 of organizational oversight and engagement with the issue. Visibility of this issue has not been maintained adequately so that the organization could collectively drive resolution.

During this time, the check valve inspection results have not impacted the operability of 2P-7A Emergency Feedwater (EFW) Pump or resulted in any components not able to fulfill their credited functions.

Corrective steps that have been taken and results achieved:

Since the Green Non-cited Violation (NCV) issued in 2018 for ANO-1 and ANO-2, ANO has changed the design of the EFW Pump Turbine Steam Admission Check Valves to a design better suited for the application. However, since the EFW Pump Turbine Steam Admission Check Valves are only available for internal inspection during refueling outages, there have been delays in determining the effectiveness of the current design, complicated by the vendor manufacturing issues discussed previously.

For ANO-1, an additional action to assist in addressing the condition was to change the position of the Motor Operated Valve (MOV), CV-2617, upstream of the EFW Pump Turbine Steam Admission Check Valve (MS-271), from normally open to normally closed. This eliminated the Steam Generator crosstie which causes check valve oscillations. A similar solution is not readily available for ANO-2 because the upstream MOVs do not currently receive an Emergency Feedwater Actuation System (EFAS) signal to open.

Both ANO-2 valves were inspected and replaced during the Fall 2021 refueling outage (2R28).

During this inspection, the 2MS-39B check valve was discovered to have missing parts. A vendor failure analysis report indicated the cause of the missing parts could have been caused by inadequate staking of the valve stem nut. A work order task was planned for the Spring 2023 refueling outage (2R29) to ensure the valves were assembled per the approved design prior to installation. Maintenance procedures were revised to include additional inspections to verify proper assembly prior to installation of this model check valve going forward.

The valve inspection in 2R29 determined the 2MS-39B stem nut was not staked correctly and again resulted in missing parts. ANO-2 implemented the updated maintenance procedures for stem nut staking prior to installing a new valve for 2MS-39B during 2R29. Additionally, 2MS-39A stem nut staking was verified to be correct.

Corrective steps that will be taken:

To restore compliance and resolve this Notice of Violation, ANO-2 will:

1. Replace 2MS-39A and 2MS-39B with new or manufacturer refurbished check valves during the Fall 2024 refueling outage (2R30).

2. Inspect the removed 2MS-39A and 2MS-39B check valves for wear and degradation. At this point, the effectiveness review for the current plant design will be completed to determine if it is adequate. If the current design is deemed adequate to satisfy the credited design function(s), compliance will be restored.

2CAN092301 Page 3 of 3

3. With compliance restored, ANO-2 will continue to replace 2MS-39A and 2MS-39B on an every refueling outage (1R) frequency until an adequate longer-term design solution has been explored and analyzed for possible implementation.

4. Prior to the Fall 2024 refueling outage (2R30), ANO-2 will conduct a scoping study to determine if there is another solution the site should be prepared to pursue in the event the current check valve design is determined to be inadequate (i.e., different check valve, orifice, MOV).

5. If another solution is determined to be necessary, ANO-2 will implement the selected option during the Spring 2026 refueling outage (2R31).

6. An effectiveness review will be completed during the Fall 2027 refueling outage (2R32) to validate the implemented option was effective in addressing the condition.

7. Additional corrective actions will be issued as part of the causal evaluation for this Notice of Violation to share the organizational learnings. These actions will also facilitate improvements in the use of available tools (i.e., system health reports, heat maps) so that visibility is maintained in the future for similar issues and the organization can collectively drive the issues to resolution in a timely manner.

Date when full compliance will be achieved:

Based on the actions described above, full compliance will be achieved when:

1. Current check valve design is verified to be adequate to satisfy the credited design function(s) following inspection in the Fall 2024 refueling outage (2R30).

Or

2. If the adequacy of the current check valve design to satisfy the credited design function(s) is challenged, a new design will be implemented in the Spring 2026 refueling outage (2R31) with an effectiveness review to occur in the Fall 2027 refueling outage (2R32).

Enclosure 2 2CAN092301 List of Regulatory Commitments

2CAN092301 Page 1 of 1 List of Regulatory Commitments The following table identifies those actions committed to by Entergy Operations, Inc. (Entergy) in this document. Any other statements in this submittal are provided for information purposes and are not considered to be regulatory commitments.

TYPE (Check One) SCHEDULED COMMITMENT COMPLETION ONE-TIME CONTINUING DATE ACTION COMPLIANCE Entergy will ensure instructions associated with inspections and replacement of the current design X 12/31/2023 check valves verify proper assembly per approved plant design.

Entergy will complete scoping study to determine alternate plant design to X 9/10/2024 satisfy the credited design function(s).

Entergy will verify current check valve End of Fall 2024 design is adequate, or not, to satisfy X Refueling Outage the credited design function(s). (2R30)

Entergy will implement alternate plant End of Spring design, if necessary, to satisfy the X 2026 Refueling credited design function(s). Outage (2R31)

Entergy will verify alternate plant End of Fall 2027 design is adequate, or not, to satisfy X Refueling Outage the credited design function(s). (2R32)