ML23279A067

Issuance of Relief Request I6 RR 02 - Examination of the Unit 2 Steam Generator Feedwater Nozzle Extension to Nozzle Weld Sixth 10 Year Inservice Inspection Program Interval

ML23279A067
Person / Time
Site:	Point Beach
Issue date:	11/09/2023
From:	Jeffrey Whited NRC/NRR/DORL/LPL3
To:	Coffey B Florida Power & Light Co
References
EPID L-2023-LLR-0031
Download: ML23279A067 (1)

Text

November 9, 2023 Mr. Bob Coffey Executive Vice President, Nuclear Division and Chief Nuclear Officer Florida Power & Light Company Mail Stop: EX/JB 700 Universe Blvd Juno Beach, FL 33408

SUBJECT:

POINT BEACH NUCLEAR PLANT, UNIT 2 - ISSUANCE OF RELIEF REQUEST I6-RR EXAMINATION OF THE UNIT 2 STEAM GENERATOR FEEDWATER NOZZLE EXTENSION TO NOZZLE WELD SIXTH 10-YEAR INSERVICE INSPECTION PROGRAM INTERVAL (EPID L-2023-LLR-0031)

Dear Mr. Coffey:

By letter dated June 27, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23178A142), NextEra Energy Point Beach, LLC (NextEra, the licensee) submitted relief requests (RRs) Nos. I6-RR-01, I6-RR-02, and I6-RR-03 to the U.S. Nuclear Regulatory Commission (NRC) for the use of alternatives to the requirements in American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)

Section XI, Rules for lnservice Inspection of Nuclear Power Plant Components, at Point Beach Nuclear Plant, Units 1 and 2, associated with the sixth 10-year interval inservice inspection (ISI) interval.

Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(1),

Acceptable level of quality and safety, the licensee requested to use the proposed alternative in RR I6-RR-02 on the basis that the proposed alternative will provide an acceptable level of quality and safety.

The NRC staff has reviewed the subject request and concludes, as set forth in the enclosed safety evaluation, that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(1). Therefore, the NRC staff authorizes the proposed alternatives in RR I6-RR-02, for the sixth 10-year ISI interval at Point Beach, Unit 2, which began on August 1, 2022, and is scheduled to end on July 31, 2032.

All other ASME Code,Section XI, requirements for which relief was not specifically requested and approved in the subject requests for relief remain applicable, including third-party review by the Authorized Nuclear lnservice Inspector.

The RRs identified as I6-RR-01 and I6-RR-03 will be handled under separate NRC correspondence.

B. Coffey If you have any questions, please contact the Project Manager, at 301-415-2855 or email at Scott.Wall@nrc.gov.

Sincerely, Digitally signed by Jeffrey Jeffrey A. A. Whited Date: 2023.11.09 Whited 10:18:06 -05'00' Jeffrey A. Whited, Chief Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-266 and 50-301

Enclosure:

Safety Evaluation cc: Listserv

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REGARDING THE SIXTH 10-YEAR INTERVAL INSERVICE TESTING INTERVAL 10 CFR 50.55a RELIEF REQUEST I6-RR-02 POINT BEACH NUCLEAR POWER PLANT, UNIT 2 NEXTERA ENERGY POINT BEACH. LLC DOCKET NO. 50-301

1.0 INTRODUCTION

By letter dated June 27, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23178A142), NextEra Energy Point Beach, LLC (NextEra, the licensee) submitted relief requests (RRs) Nos. I6-RR-01, I6-RR-02, and I6-RR-03 to the U.S. Nuclear Regulatory Commission (NRC) for the use of alternatives to the requirements in American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)

Section XI, Rules for lnservice Inspection of Nuclear Power Plant Components, at Point Beach Nuclear Plant (Point Beach), Units 1 and 2, associated with the sixth 10-year interval inservice inspection (ISI) interval which began on August 1, 2022, and is scheduled to end on July 31, 2032.

Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(z)(1),

Acceptable level of quality and safety, the licensee requested to use the proposed alternative in RR I6-RR-02, for a unique weld configuration at Point Beach, Unit 2, on the basis that the proposed alternative will provide an acceptable level of quality and safety. The alternatives contained in I6-RR-01 and I6-RR-03, will not be discussed further in this safety evaluation (SE) and will be handled under separate correspondence.

2.0 REGULATORY EVALUATION

The NRC regulations in 10 CFR 55a(g)(4), Inservice inspection standards requirement for operating plants, require that ASME Code Class 1, 2 and 3 components meet the ISI requirements, except the design and access provisions set forth in Section XI of editions and addenda of the ASME Code, to the extent practical within the limitations of design, geometry, and materials of construction of the components.

Regulation 10 CFR 50.55a(z), Alternatives to codes and standards requirements, states, in part, that alternatives to the requirements of 10 CFR 50.55a(g) may be used, when authorized by the NRC, if the licensee demonstrates: (1) the proposed alternatives would provide an acceptable level of quality and safety, or (2) compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Enclosure

Based on the above, and subject to the following technical evaluation, the NRC staff finds that regulatory authority exists for the licensee to request and the NRC to authorize the alternative requested by the licensee.

3.0 TECHNICAL EVALUATION

3.1 Licensees Relief Request 3.1.1 Affected Component The affected component is a Class 2 weld, number SG-A-8, between the steam generator feedwater nozzle and a nozzle extension. The licensee has classified the weld as an Examination Category C-B, Item Number C2.21 Nozzle-to-Shell (Nozzle to Head or Nozzle to Nozzle) of the ASME Code,Section XI, Table IWC-2500-1, Pressure Retaining Welds in Pressure Vessels.

3.1.2 ASME Code of Record The 2017 Edition of the ASME Code Section XI is the code of record for the sixth 10-Year ISI program interval which began on August 1, 2022, and is scheduled to end on July 31, 2032.

3.1.3 ASME Code Requirements ASME Code Section XI Table IWC-2500-1, Examination Category C-B, Item C2.21 requires a surface and volumetric examination of the affected weld during each inspection interval and Section IWA-2232, Ultrasonic Examination, requires ultrasonic examination be in accordance with Mandatory Appendix I, Ultrasonic Examination, of ASME Code,Section XI.

Code Case N-716-2, Alternative Classification and Examination Requirements,Section XI, Division 1, provides alternative inspection requirements for Class 1 and Class 2 pipe welds based on risk considerations.

3.1.4 Reason for Request The licensee notes that they are implementing the alternative requirements in ASME Code Case N-716-2 for the sixth ISI interval. The Code Case requires the steam generator to be classified as high safety significant (HSS). Section 4(a) of the Code Case requires HSS vessels, pumps, valves, and pressure-retaining bolting be selected and examined in accordance with Section XI.

The licensee explained that the Class 2 steam generator feedwater nozzle weld configuration is unique because both replacement steam generators would not fit through the Point Beach, Unit 2, equipment hatch. As a result, the as-designed feedwater nozzles had to be removed and field weld fabricated after the recirculating steam generators were in place. The redesigned nozzle configuration includes a welded extension piece which precludes the ability to completely perform an ultrasonic testing examination at 45 and 60-degree scan angles as described in Appendix I, Supplement 9. Attachment A of the relief request shows a diagram of the nozzle extension weld configuration.

The licensee requested relief from the requirements of ASME Code,Section XI, Table IWB-2500-1, Category C-B, Item No. C2.21 because the configuration of the Point Beach, Unit 2 feedwater nozzle extension to nozzle weld does not meet any of the configurations described in Figures IWC-2500-4(a), (b), or (d).

3.1.5 Proposed Alternative The licensee stated that a surface and ultrasonic examination will be performed once, at each interval, in accordance with Table IWC-2500-1. The licensee further stated that the ultrasonic examination will utilize 30-degree and 45-degree beam angles to interrogate the lower 1/3 of the weld and adjacent base material 1/4 inch on either side of the weld as described in Figures IWC-2500-4 (a), (b), or (d). The 30-degree angle has been chosen for two reasons:

(a) the need to introduce the sound beam from the nozzle taper, and (b) the inside/outside diameter ratio is such that a shallower beam angle (e.g., 45 degrees) will not strike the inside surface of the weld. Due to the short physical length of the nozzle boss flat, scanning with the 45-degree search unit is limited, but will be performed to the maximum extent possible, as shown in Attachment-A of the relief request.

3.1.6 Basis for Alternative The licensee stated that the proposed alternative ultrasonic examination technique has been demonstrated to the Authorized Inspection Agency on a mock-up with two implanted weld solidification flaws 0.085 inches deep (1.99 percent through-wall extent). The circumferential flaw was placed in the region of the block that would equate to the weld centerline, which demonstrated the ability of the 30-degree search unit to detect a flaw while scanning the nozzle taper. The axial flaw was placed at a convenient location on the block away from the calibration reflects (side- and end-drilled holes).

3.1.7 Duration of Proposed Alternative The licensee stated that the proposed alternative will be used for the sixth 10-year ISI interval that began on August 1, 2022, and is scheduled to end on July 31, 2032.

3.2 NRC Staff Evaluation The licensee proposes to use an alternative ultrasonic examination procedure for the nozzle-to-nozzle extension weld in the feedwater system for a steam generator on the basis that the alternative provides an acceptable level of quality and safety.

The NRC staff noted that the ASME Code,Section XI, Appendix I, Supplement 9, Scan Angles, requires that two angle beams having nominal angles of 45 degrees and 60 degrees be used in performing ultrasonic examination of piping components.

In lieu of the Appendix I, Supplement 9, requirement, the proposed ultrasonic examination uses a 45-degree beam angle while scanning the flat boss region of the nozzle and uses a 30-degree beam angle while scanning the taper of the nozzle. The NRC staff noted that the short length of the nozzle prevents the 45-degree search unit from scanning the wetted surface (inner diameter (ID)) of the weld but covers the upper region of the inspection area. The 30-degree scanning unit allows interrogation of the lower third of the weld and adjacent base material. This procedure was demonstrated on a mock-up with an axial and circumferential 0.085-inch-deep flaw (1.99 percent through-wall extent). The circumferential flaw was placed in

the region of the mock-up equating to the weld centerline to demonstrate the ability of the 30-degree search unit to detect a flaw while scanning from the nozzle taper. The NRC staff determined that the proposed procedure does not meet the angle beam requirements of Appendix I, Supplement 9, of the ASME Code,Section XI. However, the NRC staff noted that the use of an alternative inspection procedure with 100 percent coverage of the wetted surface (ID) is preferable to the use of a compliant inspection procedure which results in less than 100 percent coverage.

The NRC staff noted that the relief request does not specify the composition of the base or weld material which could affect the reliability and accuracy of the ultrasonic examination. However, this information was previously provided by the licensee in a letter dated June 15, 2015 (ML15166A146), to support its Relief Request No. 10, which involved the alternate examination of the same weld SG-A-8 for the fifth 10-Year ISI interval. The Point Beach, Unit 2 feedwater nozzle and nozzle extension assemblies were fabricated from SA-508, Class 3a. The weld metal joining the feedwater nozzles to its associated nozzle extension assembles was either ER80S-D2 or E9018M. The NRC staff determined that the use of the proposed alternative inspection procedure with these materials is not expected to be problematic.

Although not discussed in the relief request, the licensee provided in its letter dated June 15, 2015, that the calculated cumulative usage factor (CUF) for the component over its remaining lifetime is 0.9276. By letter dated September 16, 2015 (ML15246A305), the NRC staff approved Relief Request No. 10 for the fifth 10-Year ISI interval. In its SE, the NRC staff stated that based on the CUF calculation, cracking is not expected to occur in this component. The NRC staff further noted in its previous safety evaluation that CUF is relatively close to 1, but if thermal fatigue cracks do develop, they are expected to take more than one 10-year interval before they would challenge the structural integrity or leak tightness of the weld.

In addition, the licensee stated that it will perform VT-2 visual examinations of the feedwater nozzle during the scheduled feedwater pressure tests each ISI period. The NRC staff noted that the licensee is required to perform a system leakage test in accordance with the ASME Code,Section XI, Table IWC-2500-1, Examination Category C-H, Item Number C7.10 every inservice period. The NRC staff noted that the VT-2 visual examinations as part of the system leakage test could detect leakage from a through wall flaw, if it exists, such that the licensee could perform corrective actions before the pipe fails its design function.

In summary, based on the above evaluation, the NRC staff determined that the licensee proposed alternate ultrasonic examination technique will provide reasonable assurance that the licensee will be able to detect potential flaw, if it exists, in the subject weld; thereby the structural integrity of the subject weld is periodically monitored and maintained.

4.0 CONCLUSION

As set forth above, the NRC staff finds that the proposed alternative described in RR I6-RR-02 provides an acceptable level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1). Therefore, the NRC staff authorizes use of RR I6-RR-02 for the sixth 10-year ISI interval at Point Beach, Unit 2, which began on August 1, 2022, and is scheduled to end on July 31, 2032.

All other ASME Code,Section XI requirements for which relief was not specifically requested and approved remain applicable, including third-party review by the Authorized Nuclear inservice inspector.

Principle Contributor: S. Levitus, NRR Date: November 9, 2023

ML23279A067 *via memo NRR-028 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DNRL/NVIB/BC (A)*

NAME SWall SRohrer (ABaxter for) JTsao DATE 10/05/2023 10/10/2023 09/15/2023 OFFICE NRR/DORL/LPL3/BC NRR/DORL/LPL3/PM*

NAME JWhited SWall DATE 11/09/2023 11/09/2023