ML24103A001
| ML24103A001 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 04/11/2024 |
| From: | Audrey Klett Plant Licensing Branch 1 |
| To: | Brown K, Krick M Susquehanna |
| Klett A | |
| References | |
| EPID L-2024-LLR-0028 | |
| Download: ML24103A001 (1) | |
Text
From: Audrey Klett To: Brown, Katie-Elizabeth Rosser Cc: Krick, Melisa
Subject:
Susquehanna Steam Electric Station, Unit 1 - Summary of Verbal Authorization of 4RR-11 [EPID L-2024-LLR-0028]
Date: Thursday, April 11, 2024 4:24:00 PM Attachments: Susquehanna Unit 1 - Script for Verbal Authorization of 4RR-11.pdf
- Katie, In accordance with Office of Nuclear Reactor Regulation Office Instruction LIC-102, Revision 3, Review of Relief Requests, Proposed Alternatives, and Requests to Use Later Code Editions and Addenda (ML18351A218), effective today, April 11, 2024, and as discussed in todays meeting held at 3:30 pm EDT, the U.S. Nuclear Regulatory Commission (NRC) staff communicated its verbal authorization of Relief Request 4RR-11 submitted by Susquehanna Nuclear, LLC (the licensee) on April 9, 2024 (ML24100A832),
as supplemented by letter dated April 11, 2024 (ML24102A022).
The licensee requested an alternative to American Society of Mechanical Engineers Boiler and Pressure Vessel Code(ASMECode),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Paragraph IWB-5222(b) requirements for Susquehanna Steam Electric Station(Susquehanna), Unit 1. The alternative allows the licensee to defer the system leakage test for the volume between the inboard and outboard main steam isolation valves on the D main steam line until the next Susquehanna, Unit1 refueling and inspection outage expected in spring2026.
Attached to this email is the script used for the NRC staffs verbal authorization, as provided by Matthew Mitchell and Hipolito Gonzalez. This e-mail will be added to ADAMS as a publicly available official agency record, documenting the staffs verbal authorization. The NRC staffs safety evaluation will be transmitted via separate correspondence within approximately 150 days.
Please contact me if you have any questions regarding this action.
The following NRC and licensee personnel participated in the meeting:
NRC Hipolito Gonzalez Matthew Mitchell Jonathan Grieves Audrey Klett John Honcharik Thomas Scarbrough Jen England Sherlyn Haney Erin Brady Elena Herrera Torres Theo Edwards Jeff Smith
Susquehanna Nuclear, LLC Melissa Krick Mark Jones John Waclawski Keysha Anderson Brad Yarzebinski Lonnie Crawford
Audrey Klett, Senior Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing Plant Licensing Branch 1 301-415-0489
VERBAL AUTHORIZATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELIEF REQUEST 4RR-11 (PROPOSED ALTERNATIVE)
REGARDING D M AIN STEAM LINE SYSTEM LEAKAGE TEST SUSQUEHANNA NUCLEAR, LLC SUSQUEHANNA STEAM ELECTRIC STATION, UNIT 1 DOCKET NO. 50-387 EPID L-2024-LLR-0028
Technical Evaluation read by Matthew Mitchell, Chief of the Piping and Head Penetration Branch, Office of Nuclear Reactor Regulation
By letter dated April 9, 2024 (Agencywide Documents Access and Management System Accession No. ML24100A832), as supplemented by letter dated April 11, 202 4 (ML24102A022),
Susquehanna Nuclear, LLC (the licensee) submitted Relief Request 4RR-11 to use an alternative to American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, Paragraph IWB-5222(b) requirements for Susquehanna Steam Electric Station (Susquehanna), Unit 1.
Specifically, pursuant to Title 10 of the Code of Federal Regulations (10 CFR),
Section 50.55a(z)(2), the licensee proposed to defer the system leakage test for the volume between the inboard and outboard main steam isolation valves (MSIVs) on the D main steam line until the next Susquehanna, Unit 1 refueling and inspection outage expected in spring 2026.
The licensee requested this alternative for the remainder of the current fourth 10- year inservice inspection ( ISI) interval (scheduled to end on May 31, 2024) and the portion of the fifth 10- year ISI interval that includes the period between the start of the interval (i.e., June 1, 2024) and the end of cycle 24 in spring 2026 for Susquehanna, Unit 1.
During the current refueling outage, leakage through the outboard MSIV on the D main steam line was detected during the required leak rate test per 10 CFR Part 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors. The licensee elected to repair the valve within the scope of work being performed this outage. The MSIVs are designed to prevent uncontrolled primary coolant release to the environment in the event of a steam line break downstream of the MSIVs.
The Inservice Inspection Program for Susquehanna, Unit 1 for the fourth 10 -year ISI interval is based on Section XI of the ASME Code, 2007 Edition with 2008 Addenda. TableIWB -2500- 1, Examination Category B-P, of Section XI require s specific inspections of all Class 1 pressure retaining components under Item B15.10 and Item B15.20. Item B15.10 of Table IWB-2500-1 requires a system leakage test of the Class 1 pressure boundary, which is conducted prior to a plant startup following each refueling outage in accordance with IWB-5222(a) with all valves in the position required for normal reactor startup. Item B15.20 of Table IWB-2500-1 requires testing of the Class 1 pressure boundary, which is not pressurized during the first inspection.
This second inspection is performed in accordance with IWB-5222(b) of Section XI and is required to be performed at or near the end of the 10- year ISI interval. In addition, per IWB-5222(b), this inspection may be performed in its entirety or in portions and may also be performed during the inspection conducted in accordance with IWB-5222(a). The fourth 10-year ISI interval for Susquehanna, Unit 1 ends on May 31, 2024, and, therefore, per IWB-5222(b) the leakage test is to be performed at this refueling outage. All required Class 1 pressure boundary components, except for the volume between the inboard and outboard MSIVs on the D main steam line, will be inspected per IWB-5222(b) this refueling outage.
The licensees proposed alternative would defer the IWB-5222(b) inspection for the volume between the inboard and outboard MSIVs on the D main steam line until the units next refueling outage, which is projected for spring 2026. In addition, the licensee will continue to perform the required IWB-5222(b) leakage test at or near the end of the fifth ISI interval, which is projected for 2034. The U.S. Nuclear Regulatory Commission (NRC) staff notes that the licensee provided a summary of all the inspections performed for the volume between the inboard and outboard MSIVs on the D main steam line. The volume between the inboard and outboard MSIVs on the D main steam line for this alternative was previously inspected satisfactorily in 2014, 2016, 2018, and 2020 as part of the IWB-5222(b) inspection and as part of inspections performed in accordance with IWB-5222(a) as allowed by Section XI of the ASME Code.
The intent of the IWB-5222(b) requirement to perform the inspection at or near the end of the ISI interval is to ensure that the inspection interval does not exceed 10 years. The NRC staff finds that deferring the IWB-5222(b) inspection for the volume between the inboard and outboard MSIVs on the D main steam line to 2026 would make the time between inspection to be less than 10 years. Taking into consideration the proposed inspections with the previous inspections, the volume between the inboard and outboard MSIVs on the D main steam line would have been inspected in 2014, 201 6, 2018, 2020, 2026, and 2034. In addition, the licensee had performed a satisfactory volumetric inspection of the weld upstream of the outboard isolation valve in 2020, which provides another verification on monitoring any degradation in the system.
With these inspections, the NRC staff finds that the volume between the inboard and outboard MSIVs on the D main steam line has been effectively monitored to ensure its leak tightness and structural integrity. Therefore, the NRC staff finds that the proposed alternative meet s the intent of Section XI of the ASME Code for inspecting the applicable components at least every 10 years. In addition, per supplemental letter dated April 11, 2024, the licensee stated that the information provided in the proposed alternative would justify that the proposed alternative provides for an acceptable level of quality and safety as set forth in 10 CFR 50.55a(z)(1). Based on the numerous inspections performed on the volume between the inboard and outboard MSIVs on the D main steam line that met or exceeded the requirements of IWB-5222(b),
except for the timing of the inspection, the NRC staff finds that the proposed alternative provides an acceptable level of quality and safety.
Based on the above evaluation, the NRC staff finds that the licensees proposed alternative, Relief Request 4RR-11 will provide an acceptable level of quality and safety in accordance with 10 CFR 50.55a(z)(1).
Authorization read by Hipólito González, Chief of the Plant Licensing Branch I, Office of Nuclear Reactor Regulation
As Chief of the Plant Licensing Branch I, Office of Nuclear Reactor Regulation, I concur with the conclusions of the Piping and Head Penetrations Branch.
The NRC staff determines that the proposed alternative provides an acceptable level of quality and safety. Accordingly, the NRC staff concludes that the licensee has adequately addressed all regulatory requirements set forth in 10 CFR 50.55a(z)(1).
Therefore, as of today, April 11, 2024, the NRC staff authorizes the use of the Relief Request 4RR-11 at Susquehanna, Unit 1 for the remainder of the fourth 10-year ISI interval and the portion of the fifth 10-year ISI interval that includes the period between the start of the
interval (i.e., June 1, 2024) and the end of cycle 24 (projected for spring 2026) for Susquehanna, Unit 1.
All other requirements in ASME Code,Section XI for which an alternative was not specifically requested and authorized remain applicable, including third-party review by the Authorized Nuclear Inservice Inspector.
This verbal authorization does not preclude the NRC staff from asking additional clarification questions regarding the proposed relief while subsequently preparing the written safety evaluation.