ML24290A157
| ML24290A157 | |
| Person / Time | |
|---|---|
| Site: | Farley, Vogtle  |
| Issue date: | 10/16/2024 |
| From: | John Lamb Plant Licensing Branch II |
| To: | Pournaras D, Sparkman W Southern Nuclear Operating Co |
| References | |
| L-2024-LLR-0047 | |
| Download: ML24290A157 (4) | |
Text
From:
John Lamb Sent:
Wednesday, October 16, 2024 3:03 PM To:
Pournaras, DeLisa S.; Sparkman, Wesley A.
Cc:
Joyce, Ryan M.
Subject:
For Your Action - RAI - Farley and Vogtle 1 and 2 - Alternative Request for Pressurizer Welds (L-2024-LLR-0047)
DeLisa and Wes, By letter dated July 3, 2024, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24185A245), Southern Nuclear Operating Company (SNC, the licensee) submitted a proposed alternative, Alternative GEN-ISI-ALT-2024-003, to the inservice inspection (ISI) requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)Section XI regarding the pressurizer (PZR) welds at Joseph M. Farley Nuclear Plant (Farley), Units 1 and 2, and Vogtle Electric Generating Plant (Vogtle), Units 1 and 2.
The U.S. Nuclear Regulatory Commission (NRC) staff has determined that additional information is required for the staff to complete its review. The NRC staff sent the draft requestion for additional information (RAI) on October 10, 2024, to determine if SNC needed a clarifying call. On October 16, 2024, SNC said that a clarifying call was not needed. Please respond to the below RAI within 30 days of the date of this email.
If you have any questions, contact me.
John G. Lamb Senior Project Manager NRC/NRR/DORL/LPLII-1 (301) 415-3100 REQUEST FOR ADDITIONAL INFORMATION (RAI)
By letter dated July 3, 2024, (Agencywide Documents Access and Management System (ADAMS) Accession No. ML24185A245), Southern Nuclear Operating Company (SNC, the licensee) submitted a proposed alternative, Alternative GEN-ISI-ALT-2024-003, to the inservice inspection (ISI) requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code)Section XI regarding the pressurizer (PZR) welds at Joseph M. Farley Nuclear Plant (Farley), Units 1 and 2, and Vogtle Electric Generating Plant (Vogtle), Units 1 and 2.
Specifically, pursuant to Title 10 of the Code of Federal Regulations, Part 50, Section 55a, Paragraph (z)(1) (10 CFR 50.55a(z)(1)), the licensee is proposing to perform the required volumetric examinations of the subject PZR welds every other ISI interval, rather than the ASME Code Section XI requirement of every ISI interval. SNC referred to the results of the probabilistic fracture mechanics (PFM) analyses in the following Electric Power Research Institute (EPRI) non-proprietary report as the primary basis for proposed alternative:
EPRI Technical Report 3002015905, Technical Bases for Inspection Requirements for PWR Pressurizer Head, Shell-to-Head, and Nozzle-to-Vessel Welds, 2019
(hereinafter referred to as EPRI report 15905, ADAMS Accession No.ML21021A271).
To complete its review, the Nuclear Regulatory Commission (NRC) staff requests for additional information as shown below.
Regulatory Basis Regulatory Requirement The NRC has established requirements in 10 CFR Part 50 to protect the structural integrity of structures and components in nuclear power plants. Among these requirements are the ISI requirements of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a to ensure that adequate structural integrity of PZRs (including their welds) is maintained through the service life of the vessels. Therefore, the regulatory basis for the following request for additional information (RAI) is related to demonstrating that the proposed alternative ISI requirements would ensure adequate structural integrity of the licensees PZR welds, and thereby would provide an acceptable level of quality and safety per 10 CFR 50.55a(z)(1).
RAI-1
Issue The licensee provides tables listing the affected welds at each unit in Enclosure 1, pages E1-1 through E1-3 of the proposed alternative GEN-ISI-ALT-2024-003. The component ID number provided for the Vogtle Unit 2 PZR Bottom Head to Lower Shell weld, the PZR Upper Shell to Top Head weld, the PZR Lower Shell Long Seam weld, and the PZR Upper Shell Long Seam weld are identified, as 11201-V6-002-W01, 11201-V6-002-W05, 11201-V6-002-W06, 11201-V6-002-W09, respectively. Those component ID numbers are identical to the component ID numbers provided for the Vogtle Unit 1 Upper Head To Upper Shell weld, the Lower shell to Lower Head weld, the Upper Shell Longitudinal Weld, and the Lower Shell Longitudinal Weld.
However, they differ from the Component ID numbers given in the table on pages E1-15 and E1-16 where the next scheduled examination for each component at Vogtle, Units 1 and 2, are listed.
Request Clarify the Component ID numbers for the Exam Category B2.11 and B2.12 components or welds at Vogtle, Units 1 and 2, on pages E1-1 to E1-3 and E1-15 and E1-16 and verify the other information provided, specifically the inspection dates, are correct.
RAI-2
Issue The subject alternative is proposed through the end of the sixth ISI interval for Farley, Units 1 and 2. Specifically, the alternative is requested through November 30, 2037, for Farley, Units 1 and 2. The operating license for Farley, Unit 1, expires June 25, 2037. The NRC staff notes that it cannot authorize an alternative request beyond the existing plant license date.
Request
Confirm the understanding that NRC approval of the alternative can only be authorized until the end of the currently issued license. Revise the submittal, as necessary, to address the inconsistency between the requested duration of the proposed alternative and expiration of the operating license for Farley, Unit 1.
RAI-3
Issue On page E1-12 of the proposed alternative dated July 3, 2024, SNC states that scope expansion will be performed in accordance with the ASME Section XI code of record. This description of the approach to scope expansion lacks detail and may be inconsistent with that approved by the NRC staff in prior similar alternatives. The safety evaluation (SE) dated July 22, 2024 (ML24194A022) which approved the alternative proposed by letter dated November 1, 2023 (ML23305A069), and supplemented by letter dated March 22, 2024 (ML24082A185),
provides an example of on an approach to scope expansion that the NRC staff has previously found to be acceptable.
Request (a) If indications are detected that exceed the acceptance standards of ASME Code,Section XI, IWB-3500, confirm that it will be evaluated as required by ASME Code,Section XI (which includes requirements for successive inspections and additional examinations). Describe and justify other actions (if any) specified in the plants corrective action program to ensure that the integrity of the component is adequately maintained.
(b) If indications are detected that exceed the acceptance standards of ASME Code,Section XI, IWB-3500, then scope expansion may be appropriate to assess extent of condition.
Furthermore, if industry-wide operating experience indicates that a new or novel degradation mechanism is possible in PZR welds, scope expansion may be appropriate to ensure that no such mechanism is occurring in the subject plants. Discuss and justify the detailed scope expansion plans for these scenarios.
Hearing Identifier:
NRR_DRMA Email Number:
2623 Mail Envelope Properties (MN2PR09MB50844516C931855DA4C7E483FA462)
Subject:
For Your Action - RAI - Farley and Vogtle 1 and 2 - Alternative Request for Pressurizer Welds (L-2024-LLR-0047)
Sent Date:
10/16/2024 3:03:00 PM Received Date:
10/16/2024 3:02:00 PM From:
John Lamb Created By:
John.Lamb@nrc.gov Recipients:
"Joyce, Ryan M." <RMJOYCE@southernco.com>
Tracking Status: None "Pournaras, DeLisa S." <DSPOURNA@SOUTHERNCO.COM>
Tracking Status: None "Sparkman, Wesley A." <WASPARKM@southernco.com>
Tracking Status: None Post Office:
MN2PR09MB5084.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 6931 10/16/2024 3:02:00 PM Options Priority:
Normal Return Notification:
No Reply Requested:
No Sensitivity:
Normal Expiration Date: