ML25091A146
| ML25091A146 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 04/07/2025 |
| From: | David Wrona Plant Licensing Branch II |
| To: | Coffey R Florida Power & Light Co |
| Purnell B, NRR/DORL/LPL2-2 | |
| References | |
| EPID L-2024-LLR-0059 | |
| Download: ML25091A146 (1) | |
Text
April 7, 2025 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 PROPOSED ALTERNATIVE TO INSERVICE TESTING REQUIREMENTS FOR MOTOR-OPERATED ISOLATION VALVES (EPID L-2024-LLR-0059)
Dear Robert Coffey:
By application dated August 12, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24225A100) as supplemented by \
letter dated February 7, 2025 (ML25038A069), Florida Power & Light Company (the licensee) submitted Alternative Request VR-02 for Turkey Point Nuclear Generating Unit Nos. 3 and 4 (Turkey Point Units 3 and 4, respectively). The application was submitted pursuant to paragraph 50.55a(z),
Alternatives to codes and standards requirements, of Title 10 of the Code of Federal Regulations (10 CFR).
The American Society of Mechanical Engineers (ASME) operation and maintenance code for nuclear power plants (OM Code), as incorporated by reference in 10 CFR 50.55a, Codes and standards, specifies requirements for the inservice testing (IST) of nuclear power plant components. The licensee has proposed to perform periodic inspections as an alternative to the biennial leakage test requirements in the OM Code for four motor-operated isolation valves at each Turkey Point unit (eight valves in total).
The regulations in 10 CFR 50.55a(z) state, in part, that alternatives to the requirements in paragraphs (b) through (h) of 10 CFR 50.55a may be authorized by the U.S. Nuclear Regulatory Commission (NRC) if the licensee demonstrates that: (1) the proposed alternative provides 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. Additionally, these regulations require alternatives to be authorized by the NRC staff prior to implementation by the licensee. Therefore, for the sixth 10-year IST interval for Turkey Point Unit 3, the NRC staff may only authorize the proposed alternative for the remainder of the interval, rather than for the requested duration of the interval, because the interval began on February 22, 2025.
The NRC staff has reviewed the licensees application, as supplemented, 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(z)(2). Therefore, the NRC staff authorizes the licensee to use the proposed alternative in lieu of the biennial leakage test requirements in
the ASME OM Code, as incorporated by reference in 10 CFR 50.55a, for the subject valves at Turkey Point Units 3 and 4. This authorization is for (1) the remainder of the fifth 10-year IST interval at Turkey Point Units 3 and 4; (2) the remainder of the sixth 10-year IST interval at Turkey Point Unit 3; and (3) the duration of the sixth 10-year IST interval at Turkey Point Unit 4.
The 10-year IST intervals include any extensions to the period for completing IST requirements that are allowed by 10 CFR 50.55a.
All other ASME OM Code requirements, as incorporated by reference in 10 CFR 50.55a, for which relief has not specifically been requested and approved remain applicable.
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 KIMBERLY GREEN Digitally signed by KIMBERLY GREEN Date: 2025.04.07 14:55:29 -04'00'
Enclosure SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION ALTERNATIVE REQUEST VR-02 FLORIDA POWER & LIGHT COMPANY TURKEY POINT NUCLEAR GENERATING UNIT NOS. 3 AND 4 DOCKET NOS. 50-250 AND 50-251 1.0 INTRODUCTION By application dated August 12, 2024 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24225A100), as supplemented by \
letter dated February 7, 2025 (ML25038A069), Florida Power & Light Company (the licensee) submitted Alternative Request VR-02 for Turkey Point Nuclear Generating Unit Nos. 3 and 4 (Turkey Point Units 3 and 4, respectively). The application was submitted pursuant to paragraph 50.55a(z),
Alternatives to codes and standards requirements, of Title 10 of the Code of Federal Regulations (10 CFR).
The American Society of Mechanical Engineers (ASME) operation and maintenance code for nuclear power plants (OM Code),1 as incorporated by reference in 10 CFR 50.55a, Codes and standards, specifies requirements for the inservice testing (IST) of nuclear power plant components. The licensee proposed to perform periodic inspections as an alternative to the biennial leakage test requirements in the OM Code for four motor-operated isolation valves at each Turkey Point unit (eight valves in total).
2.0 REGULATORY EVALUATION
The regulations in 10 CFR 50.55a(f)(4) state, in part, that throughout the service life of a boiling or pressurized water-cooled nuclear power facility, pumps and valves that are within the scope of the ASME OM Code must meet the IST requirements (except design and access provisions) set forth in the OM Code and addenda that become effective subsequent to editions and addenda specified in 10 CFR 50.55a(f)(2) and (3) and that are incorporated by reference in 10 CFR 50.55a(a)(1)(iv), to the extent practical within the limitations of design, geometry, and materials of construction of the components.
The regulations in 10 CFR 50.55a(z) state, in part, that alternatives to the requirements in paragraphs (b) through (h) of 10 CFR 50.55a may be authorized by the U.S. Nuclear Regulatory Commission (NRC) if the licensee demonstrates that: (1) the proposed alternative provides an acceptable level of quality and safety, or (2) compliance with the specified requirements would 1 The title and specific portions of the ASME OM Code incorporated by reference in 10 CFR 50.55a varies by edition and addenda (see 10 CFR 50.55a(a)(1)(iv) for details).
result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. Additionally, these regulations require alternatives to be authorized by the NRC staff prior to implementation by the licensee.
3.0 TECHNICAL EVALUATION
3.1 Licensees Request 3.1.1 ASME Code Components Affected The proposed alternative is applicable to four motor-operated isolation valves at each Turkey Point unit (eight valves in total). The subject valves function in the open position to provide flow to and from the refueling water storage tanks (RWST) during normal and emergency operations.
The subject valves at each unit consist of the following:
Two 2-inch globe valves installed in series to isolate the high-head safety injection pump recirculation flow path back to the associated RWST.
Two 16-inch double-disk gate valves installed in series to isolate the high-head safety injection, residual heat removal, and containment spray pump suction lines from the associated RWST.
3.1.2 Applicable ASME OM Code Edition and Addenda At the time the application was submitted, Turkey Point Units 3 and 4 were both in the fifth 10-year IST intervals and required to comply with the 2004 Edition through the 2006 Addenda of the ASME OM Code, as incorporated by reference in 10 CFR 50.55a. The application stated that the sixth IST intervals were to begin on February 22 and April 15, 2025, for Turkey Point Units 3 and 4, respectively. The applicable code of record for the sixth 10-year IST intervals is the 2020 Edition of ASME OM Code, as incorporated by reference in 10 CFR 50.55a.
3.1.3 Applicable ASME OM Code Requirements The application states that the subject valves were recently recategorized as Category A valves under the ASME OM Code. Paragraph ISTC-3630, Leakage Rate for Other Than Containment Isolation Valves, of the OM Code states that Category A valves with a leakage requirement not based on an Owners 10 CFR 50, Appendix J program, shall be tested to verify their seat leakages within acceptable limits. Subparagraph ISTC-3630(a), Frequency, requires these tests to be conducted at least once every 2 years.
3.1.4 Licensees Proposed Alternative The licensees proposed alternative to testing the seat leakage of the subject valves every 2 years is described in its August 12, 2024, application, as revised by the supplemental \
letter dated February 7, 2025. The proposed alternative is to inspect the valve seating surface every four refueling outages via performance of disk-to-seating surface blue check. Under the proposed alternative, the licensee stated that these valve inspections will be staggered such that the time between inspections of redundant components would be less than three refueling outages. The licensee is transitioning to 24-month fuel cycles such that four refueling outages would correspond to approximately 8 years.
The licensee stated that blue checks assure valve seating surfaces are free of scratches and defects that can contribute to leakage. The licensee also stated that unsatisfactory blue check results would warrant seating surface repairs before returning the valves to operability and potentially subject the valves to more frequent inspections in accordance with the Turkey Point Equipment Reliability Program.
3.2 NRC Staffs Evaluation For the NRC staff to authorize a proposed alternative, the licensee must demonstrate that one of the two criteria in 10 CFR 50.55a(z) are met. Although the licensee claimed that the criterion in 10 CFR 50.55a(z)(1) was met, the NRC staff evaluated the application, as supplemented, against the criterion in 10 CFR 50.55a(z)(2). Specifically, the NRC staff reviewed the application to determine if the licensee had demonstrated that compliance with the specified requirements would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.
In accordance with the ASME OM Code, paragraph ISTC-3630, the licensee is required to test the subject valves at least once every 2 years to verify the seat leakage of the valves is within acceptable limits. As an alternative to this requirement, the licensee proposes to inspect the seating surface of the subject valves every four refueling outages via performance of disk-to-seating surface blue check. The licensee stated that these inspections will be staggered such that the time between inspections of redundant components would be less than three refueling outages. In addition, unacceptable results would warrant seating surface repairs before returning a subject valve to service.
Under the proposed alternative, the licensee would not perform seat leakage tests. To assure that the seat leakage would remain within the necessary limits, the licensee would rely on (1) the motor-operated valve (MOV) program to ensure that motor-operators are applying the proper sealing force and (2) the proposed alternative to use blue checks to verify that the valve seats and discs are maintaining proper surface contact.
3.2.1 Motor-Operated Valve Program The licensee stated that the seat leakage limits for the subject valves are half the assumed leakage rates in the dose analysis for a large-break loss-of-coolant accident. The licensees February 7, 2025, supplement provided the calculated seat leakage rates for the subject valves.
The NRC staff found that the calculations used conservative assumptions and showed that there was margin between the calculated seat leakage rates and the seat leakage limits for the subject valves.
The February 7, 2025, supplement states that the subject valves are controlled by the torque switch in the close direction with the measurement of torque and thrust. The licensee described how it determined that the motor-operators provided sufficient closing thrust for adequate sealing. In addition, the licensee described the acceptance criteria for the closing torque and thrust for the subject valves to avoid damage to the valve and actuator. The licensee also described its post-test evaluation.
The licensee also provided information on the past performance of the subject valves. The licensee reports that no failures of the subject valves have occurred during inservice stroke testing, position indication testing, or diagnostic testing in the previous 10 years. In its February 7, 2025, supplement, the licensee provided information on the history of the subject valves including test results. The licensee provided the results of the stroke time and position indication tests for the past five refueling outages and they were all satisfactory.
In addition, the February 7, 2025, supplement provided information on the diagnostic testing of the subject valves. In the past, the diagnostic testing of the valves was performed every six refueling outages under an 18-month operating cycle (approximately every 9 years). The licensee is transitioning Turkey Point Units 3 and 4 to 24-month operating cycles, which will result in a change in the diagnostic testing interval to every four refueling outages (approximately every 8 years). The licensee stated that diagnostic testing of the subject valves is also performed after actuator overhaul and any maintenance that could affect the required thrust or capability of the valve.
Based on this information, the NRC staff found that the licensees MOV program provides reasonable assurance that the motor-operators for the subject valves will apply adequate sealing force.
3.2.2 Proposed Alternative The licensee stated that the proposed blue checks will assure that the seating surfaces for the subject valves are free of scratches and defects that can contribute to leakage. The February 7, 2025, supplement further states:
Inspection findings that would indicate that the leakage limits might be exceeded would be rare during the eight-year time period between inspections since the valves would only be repositioned during refueling outage related testing or maintenance activities. Nevertheless, if unsatisfactory blue check results would warrant seating surface repairs, they would be completed prior to returning the valves to operable status. The identification of any time-dependent failure modes or degradations would be evaluated and potentially subject the valves to more frequent inspections in accordance with the Turkey Point Equipment Reliability Program.
The NRC staff determined that proposed inspection frequency is acceptable because the seating surfaces for the subject valves are not likely to develop scratches or defects between inspections given the limited repositioning of the valves over four refueling cycles. In addition, the licensee stated it would repair the seating surface before returning a valve to service if there are any unsatisfactory blue check results. The licensee also stated that three of the subject valves for Turkey Point Unit 3 were disassembled and internally inspected in October 2024 to provide a baseline for the proposed alternative inspections. The licensee reports that the blue checks of these valve were performed with satisfactory results. Therefore, the NRC staff finds that the proposed alternative would provide reasonable assurance that the valve seats and discs will maintain proper surface contact.
3.2.3 Compliance with the ASME OM Code The licensee stated that the subject valves were recently recategorized as Category A valves.
As a result of this recategorization, these valves must now comply with the periodic seat leakage testing requirements in ASME OM Code, paragraph ISTC-3630. The licensee stated that the systems in which the subject valves are located were not designed to accommodate seat leakage testing. The licensee stated that establishing a leakage test boundary for the subject valves would require aligning numerous boundary valves to provide a test pressure barrier. The licensee stated that testing the subject valves online would render large portions of the emergency core cooling system inoperable for extensive periods of time and increase online risk. The licensee stated that testing the subject valves during shutdown could cause extensive delays in refueling operations and planned maintenance. In addition, the licensee indicated that the large test volume that would result from the boundary valve alignments would yield unreliable leakage test results due to voids and external leakage from other boundary valves.
Based on this information, the NRC staff finds that compliance with the periodic seat leakage testing requirements in the ASME OM Code, paragraph ISTC-3630, for the subject valves would result in a hardship or unusual difficulty.
3.2.4 Technical Conclusion Based on the information provided in the licensees application, as supplemented, the NRC staff found that the licensees MOV program provides reasonable assurance that the motor-operators for the subject valves will apply adequate sealing force. The NRC staff also found that the proposed alternative provides reasonable assurance that the valve seats and discs will maintain proper surface contact. Therefore, the NRC staff concludes that implementation of the proposed alternative in conjunction with the licensees MOV program provides reasonable assurance that the subject valves will be operationally ready to maintain seat leakage rates within allowable limits during accident and post-accident conditions.
In addition, the NRC staff found that compliance with the periodic seat leakage testing requirements in the ASME OM Code, paragraph ISTC-3630, for the subject valves would result in a hardship or unusual difficulty. Therefore, the NRC staff also concludes that compliance with these requirements for the subject valves would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety when compared to the proposed alternative.
3.2.5 Implementation of Proposed Alternative The licensee requested the proposed alternative to be authorized for the remainder of the fifth 10-year IST interval and for the duration of the sixth 10-year IST interval at Turkey Point Units 3 and 4. The application states that the sixth IST intervals were to begin on February 22, 2025, for Unit 3 and April 15, 2025, for Unit 4. Therefore, the fifth 10-year IST intervals would be expected to end on February 21, 2025, for Unit 3 and April 14, 2025, for Unit 4. In addition, the licensees August 12, 2024, application and February 7, 2025, supplement both state that the proposed alternative would tentatively begin the next scheduled Unit 3 outage in Spring 2026 and Unit 4 outage in Spring 2025. However, the licensee requested authorization of the proposed alternative by June 2025 before the biennial leakage test (with a 25 percent extension) for the fifth 10-year IST interval is due.
The regulations in 10 CFR 50.55a(z) state, in part, that a proposed alternative must be authorized by the NRC staff prior to implementation by the licensee. Therefore, the NRC staff cannot retroactively authorize a proposed alternative. The timing of the NRC staffs authorization may impact the licensees ability to implement the proposed alternative during the spring 2025 refueling outage for Turkey Point Unit 4. This does not preclude the licensee from implementing the proposed alternative during an allowable extension period for completing IST in the fifth interval. Additionally, as the sixth 10-year IST interval for Turkey Point Unit 3 began on February 22, 2025, the NRC staff may only authorize the proposed alternative for the remainder of the sixth interval rather than for the duration of the interval.
4.0 CONCLUSION
As set forth above, the NRC staff has determined that the licensee has demonstrated that compliance with the seat leakage test requirements in the OM Code, paragraph ISTC-3630, for the subject valves would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety when compared to the proposed alternative. Accordingly, the NRC staff concludes that the licensee has adequately addressed the regulatory requirements in 10 CFR 50.55a(z)(2). Therefore, the NRC staff authorizes the proposed alternative for (1) the remainder of the fifth 10-year IST interval at Turkey Point Units 3 and 4; (2) the remainder of the sixth 10-year IST interval at Turkey Point Unit 3; and (3) the duration of the sixth 10-year IST interval at Turkey Point Unit 4. The 10-year IST intervals include any extensions to the period for completing IST requirements that are allowed by 10 CFR 50.55a.
All other ASME OM Code requirements, as incorporated by reference in 10 CFR 50.55a, for which relief has not specifically been requested and approved remain applicable.
Principal Contributors: Thomas G. Scarbrough, NRR Nicholas Hansing, NRR Blake Purnell, NRR Date of issuance: April 7, 2025
ML25091A146 NRR-028 OFFICE NRR/DORL/LPL2-2/PM NRR/DORL/LPL2-2/LAiT NRR/DEX/EMIB/BC NAME BPurnell CAdams (SL)
SBailey DATE 04/04/2025 04/04/2025 03/07/2025 OFFICE DORL/LPL2-2/BC NAME DWrona (KGreen for)
DATE 04/07/2025