ML25350C346

Inservice Testing Program Request for Alternative VRR-RBS-2025-1

ML25350C346
Person / Time
Site:	River Bend
Issue date:	12/16/2025
From:	Couture P Entergy Operations
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RBG-2025-01005, VRR-RBS-2025-1
Download: ML25350C346 (0)

Text

) entergy RBG-2025-01005 December 16, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Phil Couture Senior Manager Fleet Regulatory Assurance - Licensing 601-368-5102 10 CFR 50.55a

Subject:

lnservice Testing Program Request for Alternative VRR-RBS-2025-1 River Bend Station - Unit 1 NRC Docket Nos. 50-458 Renewed Facility Operating License No. NPF-47 In accordance with 10 CFR 50.55a, "Codes and Standards", paragraph (z)(2), Entergy Operations, Inc. (Entergy) hereby requests U.S. Nuclear Regulatory Commission (NRC) approval of the enclosed Request for Alternative for River Bend Station, Unit 1 (RBS). This request proposes an alternative to the requirements of American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code),

Mandatory Appendix I, 1-1390 for an ASME Code Class 3, Control Building Chilled Water Chiller Condenser B Service Water (SWP) Outlet Line Pressure Relief Valve, SWP-RV91 B.

Entergy is currently operating RBS in the fourth 10-year interval of the lnservice Testing (1ST)

Program in compliance with the 2004 Edition of the ASME OM Code through, and including, the 2006 Addenda. This request is for NRC approval of a proposed alternative to the Mandatory Appendix I, 1-1390, "Test Frequency, Classes 2 and 3 Pressure Relief Devices That Are Used for Thermal Relief Applications." 1-1390 requires that tests shall be performed on all Classes 2 and 3 relief devices used in thermal relief applications every 10 years, unless performance data indicates more frequent testing is necessary.

RBS Class 3 Relief Valve, SWP-RV91 B, cannot be isolated to perform the required testing and replacement without rendering Division II of Standby Service Water (SSW) inoperable due to leaking isolation valves. As a result, the earliest SWP-RV91 B can be tested to meet ASME OM Code, Mandatory Appendix I, 1-1390 requirements is during the refueling outage starting in Spring 2027. Entergy is proposing a one-time extension in accordance with 10 CFR 50.55a(z)(2) citing hardship without a compensating increase in quality and safety, because performing the test would require a cold shutdown.

The Enclosure to this letter contains the subject 1ST Request for Alternative.

Entergy Operations, Inc., 1340 Echelon Parkway, Jackson, MS 39213

RBG-2025-01005 Page 2 of 2 This document contains no new regulatory commitments.

If you have any questions regarding this request, please contact Mr. Jack McCoy, Regulatory and Emergency Planning Manager, at 225-381-3310.

Respectfully, Philip Couture Phil Couture PC/hpk

Enclosure:

cc:

Digitally signed by Philip Couture Date: 2025.12.16 15:54:03 -06'00' lnservice Testing (1ST) Request for Alternative VRR-RBS-2025-1 NRC Region IV Regional Administrator - Region IV NRC Senior Resident Inspector River Bend Station NRC Project Manager RBS Entergy Operations, Inc., 1340 Echelon Parkway, Jackson, MS 39213

Enclosure RBG-2025-01005 lnservice Testing (1ST) Request for Alternative VRR-RBS-2025-1

RBG-2025-01005 Enclosure Page 1 of 5 TABLE OF CONTENTS 1.0 TITLE AND REQUEST FOR ALTERNATIVE NUMBER................................................. 2 2.0 INTERVAL...................................................................................................................... 2 3.0 APPLICABLE CODE AND ADDENDA............................................................................ 2 4.0 COMPONENT CODE CATEGORY/ CLASS.................................................................. 2 5.0 SYSTEM AND COMPONENT FUNCTION..................................................................... 2 6.0 OM CODE TEST REQUIREMENT................................................................................. 3 7.0 REASON FOR RELIEF REQUEST................................................................................ 3 8.0 PROPOSED ALTERNATIVE TESTING AND DURATION.............................................. 4 9.0 BASIS/ JUSTIFICATION FOR RELIEF REQUEST........................................................ 4 10.0 PRECEDENCE.............................................................................................................. 5

11.0 REFERENCES

............................................................................................................... 5

RBG-2025-01005 Enclosure Page 2 of 5 INSERVICE TESTING (1ST) REQUEST FOR ALTERNATIVE VRR-RBS-2025-1 1.0 TITLE AND REQUEST FOR ALTERNATIVE NUMBER 1ST Program Request for Alternative VRR-RBS-2025-1 for SWP-RV91 B, Control Building Chilled Water Chiller Condenser B Service Water Outlet Line Pressure Relief Valve.

2.0 INTERVAL The 4th 10-Year 1ST Interval began on December 1, 2017, and ends November 30, 2027.

3.0 APPLICABLE CODE AND ADDENDA American Society of Mechanical Engineers (ASME) Code for Operation and Maintenance of Nuclear Power Plants (OM Code), 2004 Edition with addenda through, and including, the ASME 0Mb Code, Addenda (OMb-2006).

4.0 COMPONENT CODE CATEGORY/ CLASS The subjected valve, SWP-RV91 B, is an ASME Code Category C, Class 3 thermal relief valve.

5.0 SYSTEM AND COMPONENT FUNCTION The Service Water System (SWP) is composed of three systems: the Normal Service Water (NSW) System, the Standby Service Water (SSW) System, and the Service Water Cooling (SWC) System. The NSW System is a closed loop system that provides cooling water to the turbine and reactor plant auxiliary systems and components (safety and non-safety). The SSW System provides cooling water to systems and components required for safe shutdown and cooldown of the plant during emergency conditions. The SWC System provides cooling water to remove heat from the NSW System.

Four SO-percent capacity SSW pumps, [SWP-P2A (B) (C) (D)], two for each redundant SSW train, are mounted vertically in the pump room of the ultimate sink. The pumps take suction from the water storage basin sump area and discharge into two 30-inch headers which run through the piping tunnels west of the fuel and auxiliary buildings.

Individual sets of redundant lines branch off the main headers to provide cooling water to safety-related coolers in the reactor, auxiliary, control, and diesel generator buildings.

RBG-2025-01005 Enclosure Page 3 of 5 7

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Figure 1 (Piping and Instrumentation diagram 09-1 OB)

SWP-RV91 Bis a 0.75-inch Crosby model JMB-WR-B relief valve. This valve has a safety function in both the open and closed position. This normally closed relief valve opens to provide overpressure protection for the Control Building HVAC Chilled Water Chiller Condenser, HVK-CHL 1 B, and associated piping. This relief valve closes to maintain SSW and ultimate heat sink inventory when no overpressure condition exists, or the valve opens and recloses.

6.0 OM CODE TEST REQUIREMENT ASME OM Code, Mandatory Appendix I, 1-1390, "Test Frequency, Classes 2 and 3 Pressure Relief Devices That Are Used for Thermal Relief Applications," states: "Tests shall be performed on all Classes 2 and 3 relief devices used in thermal relief applications every 10 years, unless performance data indicate more frequent testing is necessary. In lieu of tests, the Owner may replace the relief devices at a frequency of every 10 years, unless performance data indicate more frequent replacements are necessary."

7.0 REASON FOR RELIEF REQUEST In accordance with 10 CFR 50.55a, "Codes and Standards", paragraph (z)(2),

"Alternatives to codes and standards requirements," this proposed alternative to the testing of SWP-RV91 B is due to hardship without a compensating increase in the level of quality and safety. Service Water system leakage includes isolation valves SWP-MOV27B and SWP-V71. This prevents testing SWP-RV91 B without tagging out all of Division II SSW, which can only be done during a refueling outage. Thus, ASME OM Code, 1-1390, 10 year performance requirement will not be met when it is due on February 9, 2026. After this date RBS will not be non-compliant with the ASME OM Code.

RBG-2025-01005 Enclosure Page 4 of 5 8.0 PROPOSED ALTERNATIVE TESTING AND DURATION Entergy plans to test this valve as soon as practical to restore compliance with the OM Code. Performance of the valve test during online operations is not practical due to Service Water system leakage and requires a refueling outage. Entergy is proposing a one-time extension for approximately 12 months until the next refueling outage (Refueling Outage 24) which is currently scheduled for Spring 2027. This extension is requested in accordance with 10 CFR 50.55a(z)(2), because compliance with the 1ST requirement would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

9.0 BASIS/ JUSTIFICATION FOR RELIEF REQUEST Entergy proposes extending the test interval for SWP-RV91 B to allow for testing during the next scheduled refueling outage, Spring 2027. SWP-RV91 B was last tested on February 9, 2016. In accordance with the requirements of ASME OM Code, 1-1390, the relief valve should be tested again by February 9, 2026.

The isolation valves for SWP-RV91 B, SWP-MOV27B (Control Building Chilled Water Chiller Condenser B Service Water Supply Line Isolation Valve) and SWP-V71 (Control Building B Chiller Service Water Outlet Main Isolation Valve) both have active leakby.

This condition prevents isolating SWP-RV91 B normally.

An expanded boundary to isolate the Division II Chiller Service loop was attempted but was unable to establish adequate isolation to perform SWP-RV91 B testing. To perform the required testing on SWP-RV91 B, Division II SSW would have to be tagged out and partially drained. This would require both chillers in Division II to be declared inoperable and would require entering several Limiting Conditions for Operation (LCO) required actions and has the potential to result in an unnecessary plant shutdown:

Technical Specification (TS) 3.7.3 - Restore control room AC subsystem to operable status. Completion Time 30 days.

TS 3.7.7 - Restore control building air conditioning subsystem to operable status.

Completion Time 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with Risk Informed Completion Time (RICT) Program.

TS 3.7.1 - Restore SSW subsystem to operable status. Completion Time 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or in accordance with RICT Program.

The earliest opportunity to isolate and test SWP-RV91 B, which are required to meet ASME OM Code, 1-1390, requirements, is RF-24 (Spring 2027).

As a thermal relief valve, the only over pressure protection function of SWP-91 B is to protect an isolated Control Building HVAC Chilled Water Chiller Condenser, HVK-CHL 1 B, and associated piping from fluid expansion caused by changes in fluid temperature. Due to the inability to effectively isolate HVK-CHL 1 B and the satisfactory performance history of SWP-RV91 B during the most recent set-pressure testing

RBG-2025-01005 Enclosure Page 5 of 5 concludes that the risk of over-pressurization in the interim 12 months is assessed to be low.

Table 1, SWP-RV91 B Test History Date Work Description Results Order Set Pressure Testing 3/30/2005 00059556 and Replacement of Satisfactory SWP-RV91B Set Pressure Testing 6/4/2009 51512728 and Replacement of Satisfactory SWP-RV91B Unsatisfactory, As-found tested Set Pressure Testing lifted high at 173 psig with set pressure tolerance acceptance 6/14/2011 00268580 and Replacement of criteria of 135-165 psig.

SWP-RV91B (Reference CR-RBS-2011-04695)

Set Pressure Testing 6/7/2016 52543321 and Replacement of Satisfactory SWP-RV91B Based on the performance history and safety significance review of the subject valve, the test extension of approximately 12 months beyond the OM code requirement would not compromise safe operation of the plant through RF-24 (Spring 2027).

10.0 PRECEDENCE In the following precedents, the NRC authorized an alternative request to defer the inservice tests of thermal relief valves within the respective programs. The approved duration was for the remainder of the 10-year 1ST program interval until the subsequent scheduled refueling outages where the subject valves would be reworked or replaced. The basis and duration for the identified precedent alternative requests are similar to that being presented herein for RBS.

1. NRC letter to TVA, Sequoyah, "Sequoyah Nuclear Plant, Units 1 and 2 -Authorization of Alternative Request RV-05 for Thermal Relief Valves," ML25248A221, September 11, 2025

2. NRC letter to Vistra, Comanche Peak Nuclear Power Plant, Unit No. 1, "Authorization and Safety Evaluation for Proposed Alternative RV-1A (EPID-L-2024-LLR-0079),"

ML25111A082, April 25,2025

11.0 REFERENCES

None