ML25147A243

Relief from Inservice Inspection Requirements for the Fifth 10-Year Interval

ML25147A243
Person / Time
Site:	Turkey Point
Issue date:	06/02/2025
From:	David Wrona NRC/NRR/DORL/LPL2-2
To:	Coffey R Florida Power & Light Co
Buckberg, P. NRR/DORL 415-1383
References
EPID L-2025-LLR-0022
Download: ML25147A243 (1)

Text

June 2, 2025 Mr. Robert Coffey Executive Vice President, Nuclear and Chief Nuclear Officer Florida Power & Light Company 700 Universe Blvd.

Mail Stop: EX/JB Juno Beach, FL 33408

SUBJECT:

TURKEY POINT NUCLEAR GENERATING UNIT NOS. 3 AND 4 RELIEF FROM INSERVICE INSPECTION REQUIREMENTS FOR THE FIFTH 10-YEAR INTERVAL (EPID L-2025-LLR-0022)

Dear Mr. Coffey:

By letter dated February 21, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25052A102), Florida Power & Light Company (the licensee) submitted Relief Request Nos. 11 and 12 for Turkey Point Nuclear Generating Unit Nos. 3 and 4 (Turkey Point Units 3 and 4), respectively. The application was submitted in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii) for the fifth 10-year inservice inspection (ISI) intervals at Turkey Point Units 3 and 4, which ended on February 21 and April 14, 2024, respectively. Specifically, the licensee requested relief from the examination coverage requirements in the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME B&PV Code),Section XI, for specific welds because the licensee had determined that compliance was impractical.

The NRC staff has reviewed the licensees application and concludes, as set forth in the enclosed safety evaluation, that the licensee has adequately addressed the regulatory requirements set forth in 10 CFR 50.55a(g)(5)(iii) and that the NRC staff may grant relief in accordance with 10 CFR 50.55a(g)(6)(i). Therefore, the NRC staff grants the requested relief from the examination requirements for the subject welds for the fifth 10-year ISI intervals at Turkey Point Units 3 and 4.

All other ASME B&PV 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.

If you have any questions, please contact Blake Purnell at 301-415-1380 or via email at Blake.Purnell@nrc.gov.

Sincerely, David Wrona, Chief Plant Licensing Branch II-2 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-250 and 50-251

Enclosure:

Safety Evaluation cc: Listserv DAVID WRONA Digitally signed by DAVID WRONA Date: 2025.06.02 15:41:07 -04'00'

Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST NOS. 11 AND 12 FOR THE FIFTH 10-YEAR INSERVICE INSPECTION INTERVALS FLORIDA POWER & LIGHT COMPANY TURKEY POINT NUCLEAR GENERATING UNIT NOS. 3 AND 4 DOCKET NOS. 50-250 AND 50-251

1.0 INTRODUCTION

By letter dated February 21, 2025 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25052A102), Florida Power & Light Company (the licensee) submitted Relief Request Nos. 11 and 12 for Turkey Point Nuclear Generating Unit Nos. 3 and 4 (Turkey Point Units 3 and 4), respectively. The application was submitted in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.55a(g)(5)(iii) for the fifth 10-year inservice inspection (ISI) intervals at Turkey Point Units 3 and 4, which ended on February 21 and April 14, 2024, respectively. Specifically, the licensee requested relief from the examination coverage requirements in the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME B&PV Code),Section XI, for specific welds because the licensee had determined that compliance was impractical.

2.0 REGULATORY EVALUATION

The regulations in 10 CFR 50.55a(g)(4) state, in part, that ASME B&PV Code Class 1, 2, and 3 components (including supports) must meet the requirements, except the design and access provisions and the preservice examination requirements, set forth in Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, of the applicable editions and addenda of the ASME B&PV Code to the extent practical within the limitations of design, geometry, and materials of construction of the components.

The regulation in 10 CFR 50.55a(g)(5)(iii), states, in part, that:

If the licensee has determined that conformance with a Code requirement is impractical for its facility the licensee must notify the NRC and submit, as specified in 10 CFR Section 50.4, information in support of the determinations.

Determination of impracticality in accordance with this section must be based on the demonstrated limitations experienced when attempting to comply with the code requirements during the ISI interval for which the request is being submitted. Requests for relief made in accordance with this section must be submitted to the NRC no later than 12 months after the expiration of the initial 120-month inspection interval or subsequent 120-month inspection interval for which relief is sought.

The regulation in 10 CFR 50.55a(g)(6)(i), states that:

The Commission will evaluate determinations under paragraph (g)(5) of this section that code requirements are impractical. The Commission may grant such relief and may impose such alternative requirements as it determines are authorized by law, will not endanger life or property or the common defense and security, and are otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.

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 grant the reliefs requested by the licensee.

3.0 TECHNICAL EVALUATION

3.1 Licensees Request 3.1.1 ASME B&PV Code Components Affected The affected components are ASME Class 1 and Class 2 pressure-retaining piping welds under the risk-informed ISI program and Class 2 vessel welds. Information from the application regarding the specific welds and their examination is summarized in tables 1 and 2 below.

Table 1: Turkey Point Unit 3 Affected Welds Examination Category Item No.

Weld ID Weld Type Coverage Obtained (%)

Angle Modes1 R-A R1.20 3-SI-2301-1 Flange-to-Elbow 45.4 45S, 60S, 70S R-A R1.20 3-SI-2301-4 Pipe-to-Valve 50 45S, 60S, 70S R-A R1.20 3-SI-2303-2312 Valve-to-Pipe 50 45S, 60S,70S R-A R1.20 3-SI-2303-24 Valve-to-Elbow 45.4 45S, 60S, 70S R-A R1.20 4-SI-2303-49 Pipe-to-Valve 47.3 45S, 60S, 70S R-A R1.11 12-RC-1301-1 Branch Connection-to-Pipe 87.5 45S, 60S, 70S C-A C1.20 3-RHE-A1 Head-to-Shell Weld 61.0 45S, 60L, 45L C-A C1.10 3-RHE-A2 Shell-to-Flange Weld 40.0 45S, 60L, 45L 1 Angle is in degrees. S is shear wave. L is longitudinal wave.

Table 2: Turkey Point Unit 4 Affected Welds Examination Category Item No.

Weld ID Weld Type Coverage Obtained (%)

Angle Modes1 R-A R1.20 3-SI-2401-1 Flange-to-Elbow 45.4 45S, 60S, 70S R-A R1.11 3-CH-1401-37 Elbow-to-Branch Connection 84 45S, 60S, 70S R-A R1.11 3-CH-1402-4320 Pipe-to-Valve 50 45S, 60S, 70S R-A R1.11 3-CH-1402-4420 Valve-to-Pipe 50 45S, 60S, 70S R-A R1.20 4-SI-2401-56 Elbow-to-Pipe 79.25 45S, 60S, 70S R-A R1.20 31-RCS-1403-8 Elbow-to-Pipe 85 45L, 45S, 60L C-A C1.20 4-RHE-A1 Head-to-Shell Weld 51.5 45S, 60S,70S, 60L C-A C1.10 4-RHE-A2 Shell-to-Flange Weld 43.0 45S, 60S,70S, 60L C-B C2.21 4-RHE-A11 Outlet Nozzle-to-Shell Weld 53.5 45S, 60S,70S, 45L, 60L 3.1.2 Applicable ASME B&PV Code Edition and Addenda The code of record for the fifth 10-year ISI intervals at Turkey Point Units 3 and 4 was the 2007 Edition with the 2008 Addenda of the ASME B&PV Code,Section XI. The fifth ISI interval at Turkey Point Unit 3 began on February 22, 2014, and ended on February 21, 2024. The fifth ISI interval at Turkey Point Unit 4 began on April 15, 2014, and ended on April 14, 2024.

By letter dated October 26, 2016 (ML16293A778), the NRC authorized the licensee to implement a risk-informed ISI program for the fifth 10-year ISI intervals at Turkey Point Units 3 and 4 for Class 1 and Class 2 piping welds.

3.1.3 Applicable ASME B&PV Code RequirementsSection XI and associated code cases of the ASME B&PV Code specify examination requirements by examination category and item number (see tables 1 and 2 above). For the subject welds in Examination Category C-A, the ASME B&PV Code requires essentially 100 percent volumetric examination of the weld length. For the subject weld in Examination Category C-B, the ASME B&PV Code requires essentially 100 percent volumetric examination and surface examination of the nozzle to vessel welds. For the subject welds in Examination Category R-A, the ASME B&PV Code requires essentially 100 percent volumetric examination of the circumferential welds selected per the risk-informed ISI program.

Paragraph IWA-2200(c) of the ASME B&PV Code,Section XI, states, in part, that: Essentially 100% coverage is achieved when the applicable examination coverage is greater than 90%;

however, in no case shall the examination be terminated when greater than 90% coverage is achieved, if additional coverage of the required examination surface or volume is practical.

Subarticle I-3200, Piping, of the ASME B&PV Code,Section XI, includes the following examination coverage requirements:

1. The required piping examination volume shall be examined in two axial directions. When examination in the circumferential direction is required, the circumferential examination must be performed in two directions.

2. When examination of ferritic welds from both sides is not possible, procedures and personnel qualified for single-side examination shall be used to examine the required volume.

3. When examination of austenitic welds from both sides is not possible, procedures and personnel qualified for single-side examination with all flaws on the opposite side of the weld, shall be used to examine the required volume.

The applicable requirements for the qualification of procedures and personnel are in Appendix VIII, Performance Demonstration for Ultrasonic Examination Systems, of the ASME B&PV Code,Section XI.

3.1.4 Reason for Request and Alternatives The licensee requested relief from the ASME B&PV Code,Section XI, examination coverage requirements for the subject welds for the fifth 10-year ISI intervals at Turkey Point Units 3 and 4 because compliance with the requirements was impractical. As the licensee was not able to meet the examination coverage requirements, the licensee proposed the following alternative:

1. Periodic system pressure tests in accordance with the ASME B&PV Code,Section XI, requirements.

2. Conduct ultrasonic examinations to the maximum extent possible.

3. Performance of regular walkdowns to check for leakage, piping configuration, and damage.

The licensee stated that the ultrasonic and visual examinations performed during the fifth ISI intervals at Turkey Point Units 3 and 4 had acceptable results.

3.2 NRC Staffs Evaluation 3.2.1 Evaluation of Examination Category R-A Welds The Turkey Point risk-informed ISI program requires periodic examinations of selected pressure-retaining austenitic stainless piping welds in Examination Category R-A. For the selected welds, essentially 100 percent volumetric examinations and an additional 1/2 -inch of adjacent base metal, as delineated in Figures IWB-2500-8 and IWC-2500-7(a) of the ASME B&PV Code,Section XI, is required. However, volumetric examinations are limited by the design geometry and materials of fabrication of the subject piping welds, as detailed in the licensees submittal. To gain access for examination, the licensee stated that the welds and associated piping would require design modifications.

As shown on the sketches and technical descriptions included in the licensees submittal, examinations of the subject welds have been performed to the extent practical with the licensee obtaining volumetric coverage ranging from 45.4 to 82 percent for the selected piping welds in Examination Category R-A (see tables 1 and 2). As discussed in the submittal, access for examination of the subject piping welds is limited primarily to one side of these welds because of the weld location and component configurations.

The licensee conducted volumetric examinations on the subject welds with equipment, procedures, and personnel that have been performance demonstrated to the requirements outlined in ASME B&PV Code,Section XI, Appendix VIII. These techniques were demonstrated for flaws located on the near-side of the welds, and the licensee stated that detection of flaws on the far-side was on a best-effort basis. The licensees ultrasonic scanning techniques included combinations of 45-, 60-, and 70-degree shear waves. Performance Demonstration Initiative (PDI) procedure demonstrations suggest that a 70-degree shear wave technique is appropriate for opposite side flaw detection for thicknesses equal to or less than 0.50 inches when examination scanning is limited to one side of the weld. While the licensee has only taken credit for limited volumetric coverage obtained from one side, it is expected that the techniques employed would have provided some coverage beyond the near side of the welds. These examinations yielded acceptable results during the performance of the volumetric examinations.

Based on the information provided, the NRC staff finds that it is impractical for the licensee to meet the required volumetric examination coverage for the subject, Examination Category R-A piping welds due to their design configurations. Although the required coverage could not be obtained, the ultrasonic techniques employed by the licensee have provided full volumetric coverage for the near side of the welds and limited volumetric coverage for the weld fusion zone and base materials on the opposite side of the welds. Based on the aggregate volumetric coverage achieved for the subject welds with acceptable results, the NRC staff has reasonable assurance that if significant service-induced degradation was present, evidence of it would have been detected. Therefore, the NRC staff determined that the volumetric examinations performed in combination with the licensees walkdowns and periodic pressure tests provide reasonable assurance of the structural integrity of the subject welds.

3.2.2 Evaluation of Examination Category C-A and C-B Welds The ASME B&PV Code,Section XI, requires periodic examination of pressure retaining welds on Class 2 pressure vessels in Examination Categories C-A and C-B. The licensee identified five heat exchanger welds in the residual heat removal systems at Turkey Point Units 3 and 4 where essentially 100 percent volumetric examination coverage could not be achieved during the fifth ISI intervals at Turkey Point Units 3 and 4. The licensee stated that the examination was limited due to component configuration and proximity of other components.

The licensee achieved an examination coverage ranging from 40 percent and 61 percent of the required weld volume for the subject welds in Examination Categories C-A and C-B (see tables 1 and 2). The licensees examined the welds based on the required examination volume in the ASME B&PV Code,Section XI, Figure IWC-2500-1. The examination techniques are described in the application and are summarized in tables 1 and 2 above.

The licensee stated that the heat exchanger shells are fabricated with stainless steel material.

For austenitic stainless-steel welds, current ultrasonic examination technology cannot reliably detect or size flaws on the far side of an austenitic weld if the weld can only be examined on one side instead. In addition, there is currently no PDI qualified single-sided ultrasonic examination procedures to provide equivalency to dual-sided examination procedures. The NRC staff noted that the PDI certificates for austenitic piping list the limitation that single-sided examinations are performed on a best-effort basis.

The licensee stated that ultrasonic longitudinal wave transducers have been shown to provide enhanced detection on the far-side of austenitic stainless-steel welds. However, the licensee stated that the coverage obtained during the examination for single-sided examinations has no code coverage credit taken for the far side of the weld, such that no austenitic weld will have greater than 50 percent coverage. The licensee explained that even though limited volumetric coverage obtained from primarily one side of the weld, the ultrasonic examination would have provided coverage beyond the near-side of the heat exchanger welds.

The NRC staff recognized that examination coverages for the subject welds are limited due to the impediments described in the licensees submittal. The NRC staff determined that the licensee achieved best effort examination coverage for the subject welds because the licensee examined the welds to the maximum extent practical, given the impediments for the subject welds.

The NRC staff determined that the examination coverage for the subject welds is limited due to the design configuration of these components and proximity of surrounding appurtenances.

Based on the diagram provided in the submittal, the NRC staff determined that to achieve essentially 100 percent examination coverage, the licensee would have to modify the heat exchangers and associated welds. The NRC staff finds that such modifications would be a significant engineering and construction effort and would place a burden on the licensee; therefore, the NRC staff finds that compliance with the ASME B&PV Code,Section XI, examination requirements for the subject welds is impractical.

The licensee stated that the ultrasonic and visual examinations of the subject welds performed during the fifth ISI intervals at Turkey Point Units 3 and 4 had acceptable results. Therefore, the NRC staff determined that the volumetric examinations performed in combination with the licensees walkdowns and periodic pressure tests provide reasonable assurance of the structural integrity of the subject welds in Examination Categories C-A and C-B.

4.0 CONCLUSION

As set forth above, the NRC staff determined that compliance with the ASME B&PV Code,Section XI, examination coverage requirements for the subject welds during the fifth ISI interval at Turkey Point Units 3 and 4 was impractical. The NRC staff further determined that the combination of the limited examination coverage, periodic system pressure tests, and periodic walkdowns provide reasonable assurance of the structural integrity of the subject welds.

Accordingly, the NRC staff finds that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(g)(5)(iii). The NRC staff concludes that granting relief pursuant to 10 CFR 50.55a(g)(6)(i) is authorized by law and will not endanger life or property or the common defense and security and is otherwise in the public interest giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility. Therefore, the NRC staff grants the requested relief from the examination requirements for the subject welds for the fifth 10-year ISI intervals at Turkey Point Units 3 and 4, which ended on February 21 and April 14, 2024, respectively.

All other ASME B&PV 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.

Principal Contributors: Varoujan Kalikian, NRR John Tsao, NRR Date of Issuance: May 30, 2025

ML25147A243 NRR-028 OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LAiT NRR/DNRL/NPHP/BC NAME BPurnell CAdams (SL)

MMitchell DATE 5/28/2025 5/29/2025 5/12/2025 OFFICE NRR/DNRL/NVIB/BC DORL/LPL2-2/BC DORL/LPL2-2/BC (signed)

NAME ABuford (MMitchell for)

DWrona DWrona DATE 5/12/2025 5/30/2025 6/2/2025