ML25181A776
| ML25181A776 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 06/30/2025 |
| From: | Couture P Entergy Operations |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| CNRO2025-00021 | |
| Download: ML25181A776 (1) | |
Text
Phil Couture Senior Manager Fleet Regulatory Assurance - Licensing 601-368-5102 Entergy Operations, Inc., 1340 Echelon Parkway, Jackson, MS 39213 CNRO2025-00021 10 CFR 50.55a June 30, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Request for Alternative GGNS-PT-001 Visual Examination of Inboard Feedwater Leakage Control Piping Between Valves E38F002A/B and E38F001B Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29 Pursuant to 10 CFR 50.55a(z)(2), Entergy Operations, Inc. (Entergy), requests the NRC's approval of the attached Inservice Inspection (ISI) request for alternative for Grand Gulf Nuclear Station (GGNS), Unit 1. This request is for the current fourth interval.
The proposed request is for an alternative to the requirements of American Society of Mechanical Engineers (ASME) Code Section XI, IWB-5222(b). The proposed alternative is to visually examine the section of Inboard Feedwater Leakage Control (FWLC) piping that experience Class 2 pressure in lieu of the pressure that corresponds to 100% rated reactor power, as required by ASME Section XI. This alternative will be conducted in the last inspection period of the inspection interval.
This request is similar to relief requests submitted (References 1 and 3) and approved (References 2 and 4) for Entergy's Arkansas Nuclear One, Unit 2 (ANO-2), with respect to the ANO-2 Third (3rd) and Fourth (4th) 10-year Inservice Inspection (ISI) interval, respectively.
As discussed in the attachment, the proposed alternative avoids undue hardship and unnecessary radiation exposure without compromising the integrity of the subject piping.
This letter contains no new regulatory commitments.
Entergy requests approval of the proposed alternative by February 1, 2026, to support the Spring 2026 refueling outage. Although this request is neither exigent nor an emergency, your prompt review is requested.
CNRO2025-00021 Page 2 of 2 Should you have any questions or require additional information, please contact me at (601) 368-5102.
Respectfully, Phil Couture PC/gpn
Attachment:
Request for Alternative GGNS-PT-001
References:
- 1) Entergy Operations, Inc. (Entergy) letter to U. S. Nuclear Regulatory Commission (NRC), "Request for Alternative ANO2-PT-001 Visual Examination of Extended Reactor Coolant Pressure Boundary Piping During System Leakage Tests,"
Arkansas Nuclear One, Unit 2 (ADAMS Accession No. ML082170845), (2CAN070807) dated July 31, 2008
- 2) NRC letter to Entergy, "Arkansas Nuclear One, Unit No. 2 -
Approval of Request for Relief No. ANO2-PT-001 on End-of-Interval System Leakage Test for the Extended Reactor Coolant Pressure Boundary Piping (TAC No. MD9537)," (ADAMS Accession No. ML091280245), dated May 21, 2009
- 3) Entergy letter to NRC, "Request for Alternative ANO2-PT-002 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping," Arkansas Nuclear One, Unit 2 (ADAMS Accession No. ML19206A779), dated July 25, 2019
- 4) NRC letter to Entergy, "Arkansas Nuclear One, Unit No. 2 -
Approval of Request for Alternative ANO 2-PT-002 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping (EPID L-2019-LLR-0073)," (ADAMS Accession No. ML20083J968), dated March 26, 2020 cc:
NRC Region IV - Regional Administrator NRC Senior Resident Inspector - Grand Gulf Nuclear Station NRC Project Manager - Grand Gulf Nuclear Station Digitally signed by Philip Couture DN: cn=Philip Couture, o=Entergy, ou=Regulatory Assurance, email=pcoutur@entergy.com Date: 2025.06.30 14:16:18 -05'00' Philip Couture
Attachment CNRO2025-00021 Request for Alternative GGNS-PT-001
Attachment to CNRO2025-00021 Page 1 of 5 Request for Alternative GGNS-PT-001 Code Classes:
American Society of Mechanical Engineers (ASME) Code Class 1
References:
ASME Section XI, 2007 Edition with 2008 Addenda, IWB-5222(b)
Examination Category:
B-P Item Number(s)
B15.20 Components:
Pressure Test Zone P-1112-02 Inboard Feedwater Leakage Control Piping between valves E38F002A/B and E38F001B Unit / Inspection Interval Applicability:
Grand Gulf Nuclear Station, Unit 1 Inservice Inspection (ISI) 4th Interval (started December 1, 2017, and currently scheduled to end on November 30, 2027)
I.
CODE REQUIREMENTS ASME Section XI, IWB-5222(b) states:
The Class 1 pressure retaining boundary which is not pressurized when the system valves are in the position required for normal reactor startup shall be pressurized and examined at or near the end of the inspection interval. This boundary may be tested in its entirety or in portions and testing may be performed during the test of the boundary of IWB-5222(a).
II.
PROPOSED ALTERNATIVE Pursuant to 10 CFR 50.55a(z)(2), Entergy requests authorization to visually examine (VT-2 inspection method) the section of FWLC piping that experiences Class 2 pressure during the Class 2 system leakage test, which is conducted in the last inspection period of the inspection interval for the components identified in Section I, above.
Attachment to CNRO2025-00021 Page 2 of 5 III.
BASIS FOR PROPOSED ALTERNATIVE Performing the leakage test of the Class 1 boundary beyond the inboard isolation valves at or near the end of each inspection interval requires conditions that place the plant in abnormal configurations or requires off-normal activities to pressurize the subject piping (Reference Figure). These challenges include:
Modification of FWLC system vent/drain piping to install test connections.
Remove Check Valves E38F002A/B and install blind flanges at those connections.
Install external pressure source at modified test connection to perform test.
Remove blind flanges and reinstall check valves E38F002A/B.
These off-normal configurations and challenges have a potential to adversely impact normal plant start-up because of the critical path time and effort required to ensure system configuration is restored and tested.
The piping subject to this request is outboard of the first isolation valve and is designed to Reactor Coolant Pressure Boundary (RCPB) conditions. However, the piping is not exposed to RCPB conditions during normal operations, but only to Class 2 system conditions. While this piping is extremely difficult to test within the scope of a Class 1 leakage test, the piping can be easily aligned and tested at Class 2 conditions. Although Class 2 pressure is lower than that of Class 1 pressure, it is representative of conditions for which the subject piping is exposed during both normal and accident conditions. Additionally, if the E38F002A/B check valves leaked by (thereby pressurizing the subject piping to RCPB conditions) and a subsequent through-wall flaw existed that could only be detected at the higher pressure; leak-by and the flaw would be discovered during the Class 1 leakage test, which is performed during each refueling outage in accordance with IWB-5222(a) with the subject inboard valve closed.
The following is a description of the piping subject to this request and the burdens associated with performing the Class 1 test currently required by ASME Section XI.
The FWLC piping associated with this proposed alternative is illustrated in the attached Figure.
The piping between valves E38F002A/B and E38F001B is part of the Feedwater Leakage Control System. The FWLC system is not required to operate during normal plant operation.
The FWLC system is designed for remote manual actuation following a Loss of Coolant Accident (LOCA). For the subject piping, the sealing fluid from the Residual Heat Removal (RHR) jockey pump B discharge line shall fill each feedwater line between the containment isolation check valves. The sealing water flow through the inboard check valves shall eventually fill the feedwater line up to the reactor vessel, and, finally, the water will return to the suppression pool through the LOCA break.
Performing a 10-year Class 1 system leakage test of the piping between valves E38F002A/B and E38F001B requires a modification to the piping to install a test connection for external pressure source. This will require insulation removal, scaffolding activities, rigging activities, ASME Code welding activities, insulation replacement and post modification testing. Testing to Class 1 conditions would also require removing the E38F002A/B check valves and
Attachment to CNRO2025-00021 Page 3 of 5 installing a blind flange on the piping at those locations. This will require insulation removal, scaffolding activities, and rigging activities. All of which will be performed twice, once to install and once remove the blind flanges.
Additional risks associated with this activity include damage to permanent plant equipment and seat leakage at downstream isolation valves, causing unnecessary delays and increased radiological exposure.
To perform the Class 1 system leakage tests described above, Entergy estimates the additional actions would require an additional radiological exposure of approximately 1.280 person-rem.
IV.
DURATION OF THE PROPOSED INTERVAL The proposed alternative identified in this request, upon approval, shall be utilized during the 4th 10-year ISI interval, which is currently scheduled to end on November 30, 2027.
V.
CONCLUSION Based on the above, Entergy concludes that imposition of the ASME Code requirements would result in a hardship without a compensating increase in quality and safety. The proposed alternative, a visual examination of the described section of piping that experiences Class 2 pressure, provides reasonable assurance of the integrity of the FWLC piping.
Entergy requests approval of the proposed alternative by February 1, 2026, to support the Spring 2026 refueling outage VI.
PRECEDENT Similar alternatives were previously requested (References 1 and 3) and approved (References 2 and 4) for Arkansas Nuclear One, Unit 2 (ANO-2) with respect to the ANO-2 Third (3rd) and Fourth (4th) 10-year ISI intervals, respectively.
VII. REFERENCES
- 1)
Entergy Operations, Inc. (Entergy) letter to U. S. Nuclear Regulatory Commission (NRC), "Request for Alternative ANO2-PT-001 Visual Examination of Extended Reactor Coolant Pressure Boundary Piping During System Leakage Tests," Arkansas Nuclear One, Unit 2 (ADAMS Accession No. ML082170845), (2CAN070807), dated July 31, 2008
- 2)
NRC letter to Entergy, "Arkansas Nuclear One, Unit No. 2 - Approval of Request for Relief No. ANO2-PT-001 on End-of-Interval System Leakage Test for the Extended Reactor Coolant Pressure Boundary Piping (TAC No. MD9537)," (ADAMS Accession No. ML091280245), dated May 21, 2009
Attachment to CNRO2025-00021 Page 4 of 5
- 3)
Entergy letter to NRC, "Request for Alternative ANO2-PT-002 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping," Arkansas Nuclear One, Unit 2 (ADAMS Accession No. ML19206A779), (2CAN071902), dated July 25, 2019
- 4)
NRC letter to Entergy, "Arkansas Nuclear One, Unit No. 2 - Approval of Request for Alternative ANO 2-PT-002 End-of-Interval System Leakage Test for Extended Reactor Coolant Pressure Boundary Piping (EPID L-2019-LLR-0073)," (ADAMS Accession No. ML20083J968), dated March 26, 2020
Attachment to CNRO2025-00021 Page 5 of 5 FIGURE Feedwater Leakage Control System