ML24045A150
| ML24045A150 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 02/15/2024 |
| From: | Ballard B Plant Licensing Branch III |
| To: | Kivi J, Mark Miller Northern States Power Co |
| Kuntz R | |
| References | |
| EPID L-2024-LLR-0015 RR-09 | |
| Download: ML24045A150 (1) | |
Text
From:
Brent Ballard To:
Miller, Michael A; Kivi, Jeffrey L Cc:
Jeff Whited; Dan Tesar
Subject:
Prairie Island Nuclear Generating Plant, Unit 2 - Verbal Authorization of Proposed Alternative RR-09 for Inservice Testing Requirements of Safety Injection System and Volume Control System Category C Check Valves Date:
Thursday, February 15, 2024 10:51:00 AM Attachments:
FINAL - Prairie Island Unit 2 verbal authorization 2-14-2024.pdf Good morning,
By web-based submission dated February 11, 2024 (Agencywide Documents Access and Management System (ADAMS) accession number ML24042A001), as supplemented by letter dated February 13, 2024 (ML24044A103), Northern States Power Company (NSPM, the licensee), a Minnesota corporation, doing business as Xcel Energy, requested alternative RR-09 to inservice testing requirements of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants (OM Code) at Prairie Island Nuclear Generating Plant, Unit 2.
The alternative request RR-09 was submitted in accordance with 10 CFR 50.55a(z)(2) on the basis that performance of inservice testing required by the ASME OM Code for the subject check valves would cause a hardship or unusual difficulty without a compensating increase in the level of quality and safety.
By teleconference on February 14, 2024, the U.S. Nuclear Regulatory Commission (NRC) staff provided a verbal authorization to NSPM for the proposed alternative RR-09. The NRC staffs verbal authorization is attached to this e-mail. The following NRC and licensee personnel participated in the conference call:
NRC Stewart Bailey - Chief, Mechanical Engineering and Inservice Testing Branch Thomas Scarbrough - Mechanical Engineer, Mechanical Engineering and Inservice Testing Branch Jeffrey Whited - Chief, Plant Licensing Branch 3 Brent Ballard - Project Manager, Plant Licensing Branch 3 Luis Cruz Rosado - Project Manager, Plant Licensing Branch 3 Sam Bina - Project Manager, Integrated Program Management and Beyond Design Basis Branch
NSPM Sara Scott - Director, Nuclear Licensing and Regulatory Affairs Michael Miller - Regulatory Affairs Manager Jeffrey Kivi - Senior Nuclear Regulatory Engineer Ronald Jacobson - Senior Nuclear Regulatory Engineer Harrison Bourgoin - Prairie Island Programs Engineer
Please contact me if you have any questions.
Thank you,
Brent Ballard Project Manager
Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission 301-415-0680
1 VERBAL AUTHORIZATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION FOR ALTERNATIVE REQUEST RR-09 SAFETY INJECTION SYSTEM AND VOLUME CONTROL SYSTEM CATEGORY C CHECK VALVE INSERVICE TESTING PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2 NORTHERN STATES POWER COMPANY DOCKET NO. 50-306 EPID L-2024-LLR-0015 FEBRUARY 14, 2024 Technical Evaluation read by Stewart Bailey, Chief, Mechanical Engineering and Inservice Testing Branch, Division of Engineering and External Hazards, NRC Office of Nuclear Reactor Regulation This call is for the NRC to verbally authorize a request by Northern States Power Company (the licensee), a Minnesota corporation, doing business as Xcel Energy, for an alternative to inservice testing requirements for specific Category C check valves in the Safety Injection system and Volume Control system at Prairie Island Nuclear Generating Plant, Unit 2.
In particular, the licensee submitted Alternative Request RR-09 electronically on February 11, 2024, with a supplemental letter dated February 13, 2024, describing its proposal. In the Alternative Request RR-09, as supplemented, the licensee proposes to defer certain inservice tests of the subject check valves required by the American Society of Mechanical Engineers (referred to herein as ASME) Operation and Maintenance of Nuclear Power Plants (referred to herein as OM Code) as incorporated by reference in Title 10 of the Code of Federal Regulations, Section 50.55a, at Prairie Island, Unit 2.
2 The NRC staff is allowed to verbally authorize alternatives to inservice testing requirements under paragraph (z) of 10 CFR 50.55a in circumstances where the licensee has docketed all pertinent information, the NRC staff has completed its review, and there is not enough time for the NRC to issue its written safety evaluation before the alternative is needed.
That is the case here.
The licensee submitted Alternative Request RR-09 in accordance with 10 CFR 50.55a(z)(2) on the basis that performance of inservice testing required by the ASME OM Code for the subject check valves in the Safety Injection and Volume Control Systems would cause a hardship or unusual difficulty without a compensating increase in the level of quality and safety.
The NRC regulations in 10 CFR 50.55a(f) require licensees to implement inservice testing programs for pumps, valves, and dynamic restraints that meet the requirements of the ASME OM Code as incorporated by reference in 10 CFR 50.55a. Prairie Island is currently implementing its Fifth 10-Year Interval Inservice Testing Program with the 2004 Edition through the 2006 Addenda of the ASME OM Code as the Inservice Testing Code of Record. The Fifth 10-Year Inservice Testing Program interval for Prairie Island, Unit 2, began on December 21, 2014, and is currently scheduled to end on December 20, 2024. The ASME OM Code requirements applicable to Alternative Request RR-09 include ASME OM Code, Subsection ISTC, paragraph ISTC-3510, titled Exercising Test Frequency, and paragraph ISTC-3522, Category C Check Valves, paragraph ISTC-3570, Valves in Systems Out of Service, and paragraph ISTC-5221, Valve Obturator Movement.
In support of the startup of Prairie Island, Unit 2, following an extended maintenance outage, the licensee proposes in Alternative Request RR-09 that the ASME [OM] Code test intervals specified in ISTC-3510, ISTC-3522(f), and ISTC-3570 be extended for check valves 2SI-7-1 and 2SI-7-2 in the Safety Injection system and check valves 2VC-8-1, 2, 3, 4, and 5,
3 and 2VC-17-1 in the Volume Control system. The check valves are OM Category C (which means self-actuating) valves without leakage limitation requirements.
The licensee proposes that the specified test intervals for the subject check valves be extended until the end of the Fifth 10-Year Inservice Testing Program interval. The licensee plans to apply the provision allowed with conditions in the ASME OM Code, Subsection ISTA, paragraph ISTA-3120, to extend the Fifth 10-Year Inservice Test Program interval for 1 year to a new end date of December 20, 2025, which will encompass the next refueling outage for Prairie Island, Unit 2, scheduled for the fall of 2025. If the Fifth 10-Year Inservice Testing Program interval is not extended, the licensee will need to conduct the required OM Code testing of the subject check valves by the current interval end date, or submit a request under 10 CFR 50.55a(z) for an alternative approach applicable to the Sixth Inservice Testing Program interval in a timely manner. In addition to the provision for testing the subject check valves by the end of the Fifth 10-Year Inservice Testing Program interval, Alternative Request RR-09, as supplemented by the licensees letter dated February 13, 2024, indicates that the subject check valves will undergo the required OM Code testing the next time plant conditions support conducting the tests.
The licensee stated that the ASME OM Code testing of the subject check valves would require flooding the refueling cavity by overflowing the reactor vessel flange. Flooding the refueling cavity would result in increased radioactive exposure to plant workers with the subsequent need for decontamination activities. The licensee also noted that the completion of the testing of the subject check valves would result in further outage time for Prairie Island, Unit
- 2.
In Alternative Request RR-09, the licensee provided the results of its review of the maintenance and testing history of the subject check valves since 2019. For example, the licensee reported that all testing of the subject Safety Injection check valves has been
4 satisfactory. Further, the licensee conducted successful preventive maintenance of Safety Injection check valve 2SI-7-1, including an internal inspection, in 2021. The licensee also conducted an internal inspection of Volume Control check valves 2VC-8-1 and 2VC-8-4 in 2021.
The licensee reported that all testing of the subject Volume Control check valves (with the exception of check valve 2VC-8-3) has been satisfactory. The licensee found that the closure test process for check valve 2VC-8-3 had not been validating forward flow prior to the closure test in accordance with the ASME OM Code. However, the licensee reported that check valve 2VC-8-3 met the differential pressure criteria for validating closure in each of the previous three refueling outages with no adverse trends.
In addition to the closure test process for check valve 2VC-8-3, the licensee identified discrepancies related to the accuracy of its current IST Program Plan for the test intervals for certain check valves during its preparation of the alternative request. The licensee stated that these discrepancies have been entered into its correction action program for resolution. The NRC staff notes that this authorization relates to future activities and does not address review of OM Code compliance for previous test activities.
Based on the information provided by the licensee, the NRC staff finds that a hardship exists without a compensating increase in the level of quality and safety, in accordance with 10 CFR 50.55a(z)(2), for the performance of specific inservice tests as scheduled in the ASME OM Code for the subject check valves as described in Alternative Request RR-09, as supplemented, at Prairie Island, Unit 2. Therefore, the NRC staff finds that the licensees proposed alternative to defer OM Code tests for the subject check valves until the end of the Fifth 10-Year Inservice Testing Program interval, or at the next opportunity that plant conditions support such testing prior to the end of the program interval, will not adversely impact the reasonable assurance that those components will be operationally ready to perform their safety functions. Based on its review, the NRC staff authorizes Alternative Request RR-09 to defer the
5 specified inservice tests for the subject check valves until the end of the Fifth 10-Year Inservice Testing Program interval, or at the next opportunity that plant conditions support such testing prior to the end of the program interval at Prairie Island, Unit 2. The NRC staff does not authorize Alternative Request RR-09 beyond the end of the Fifth 10-Year Inservice Testing Program interval, or the next opportunity that plant conditions support the OM Code testing of the subject check valves prior to the end of the program interval at Prairie Island, Unit 2.
All other ASME OM Code requirements for which relief or alternative was not specifically requested and granted or authorized as part of this alternative request remain applicable. If the licensee identifies a performance issue with any of the Safety Injection system or Volume Control system components, the licensee will be expected to take action to implement the requirements of its Technical Specifications. The NRC staffs review of Alternative Request RR-09 for Prairie Island, Unit 2, will be described in detail in a separate safety evaluation.
NRC Staff Conclusion read by Jeffrey Whited, Chief, Plant Licensing Branch 3 Division of Operating Reactor Licensing, NRC Office of Nuclear Reactor Regulation As Chief of Plant Licensing Branch 3, I concur with the conclusions of the Mechanical Engineering and Inservice Testing Branch.
The NRC staff concludes that Alternative Request RR-09, as supplemented, addresses the identified hardships or unusual difficulty without a compensating increase in the level of quality and safety for the performance of certain inservice testing required by the ASME OM Code for the specified Safety Injection system and Volume Control system check valves until the end of the Fifth 10-Year Inservice Testing Program interval, or at the next opportunity that plant conditions support such testing prior to the end of the program interval at the Prairie Island, Unit 2.
6 Accordingly, the NRC staff concludes that the licensee has adequately addressed all of the regulatory requirements set forth in 10 CFR 50.55a(z)(2) to justify the requested alternative to defer the ASME OM Code inservice testing requirements for the specified Safety Injection system and Volume Control system check valves until the end of the Fifth 10-Year Inservice Testing Program interval, or at the next opportunity that plant conditions support such testing prior to the end of the program interval.
Therefore, on February 14, 2024, the NRC authorizes Alternative Request RR-09, as supplemented, until the end of the Fifth 10-Year Inservice Testing Program interval, or at the next opportunity that plant conditions support the subject check valve testing prior to the end of the program interval at Prairie Island, Unit 2. All other requirements of the ASME OM Code, for which relief or an alternative was not specifically requested and authorized by the NRC staff, remain applicable.
This verbal authorization does not preclude the NRC staff from asking additional questions and clarifications regarding the licensees proposed alternative while preparing the subsequent written safety evaluation.