ML23298A123

NRR E-mail Capture - Palo Verde, Unit 1 - RAIs for Relief Request 70, Proposed Alternatives for Pressurizer Lower Shell Temperature Nozzle

ML23298A123
Person / Time
Site:	Palo Verde
Issue date:	10/25/2023
From:	Siva Lingam NRC/NRR/DORL/LPL4
To:	Cox M Arizona Public Service Co
References
L-2023-LLR-0057
Download: ML23298A123 (4)

Text

From: Siva Lingam Sent: Wednesday, October 25, 2023 12:29 PM To: Matthew.Cox@aps.com; Michael.Dilorenzo@aps.com Cc: Jennifer Dixon-Herrity; Matthew Mitchell; Angie Buford; John Tsao; Eric Reichelt; Steven Levitus; Carl.Stephenson@aps.com

Subject:

Palo Verde, Unit 1 - RAIs for Relief Request 70, Proposed Alternatives for Pressurizer Lower Shell Temperature Nozzle (EPID L-2023-LLR-0057)

By letter dated October 23, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23296A254), Arizona Public Service Company (the licensee) requested Nuclear Regulatory Commission (NRC) authorization of Relief Request 70, on the basis that the alternatives provide an acceptable level of quality and safety. The licensee proposed alternatives to American Society of Mechanical Engineers (ASME) Pressure Vessel Code,Section XI, 2013 Edition, and ASME Code Case N-638-10, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine [Gas Tungsten Arc Welding] GTAW Temper Bead Technique,Section XI, Division 1, regarding alternate repair of a pressurizer thermowell nozzle at Palo Verde Nuclear Generating Station (PVNGS), Unit 1.

The NRC staff requests the following official requests for additional information (RAIs) to complete its review of the alternative request:

1. Page 8 of the relief request, section B, Proposed Alternatives, second paragraph states in part that A design analysis is being performed in accordance with the design requirements of ASME Code Section III, 2013 edition. The analysis will confirm that the new nozzle will not eject from the pressurizer under design conditions Provide additional information that supports the conclusion that the preliminary design analysis demonstrates that the proposed new nozzle satisfies the design requirements of ASME Code Section III, 2013 edition, or the construction code for one fuel cycle of operation.

2. Page 9 of the relief request, section C, Basis for Flaw Analytical Evaluation, third paragraph states in part that the existing 2010 J-groove weld flaw analyses for the repaired pressurizer is used for the proposed repair. Discuss whether the 2010 flaw analysis was submitted to the NRC under previous licensing actions? If not, please provide the following information.

(a) Page 10 of the relief request, 5th paragraph states, in part, that Results from the bounding LEFM [linear elastic fracture mechanics] analysis indicated the initial and final flaw sizes on the pressurizer lower shell temperature nozzle ALJGW [As Left J-groove weld] exceeded the LEFM ASME Section XI IWB-3610 criterion for several transients.

Describe the initial flaw size in the ALJGW and how the initial flaw propagates to the final flaw sizes in the pressurizer lower shell.

(b) Page 10 of the relief request, last sentence, states that Therefore, the results from the EPFM [elastic-plastic fracture mechanics] analysis are conservative and bound the current repair OCJ [one cycle justification] in terms of safety factors. Discuss the results of the EPFM analysis performed in 2010 in terms of final flaw sizes. Discuss the acceptance criteria in the EPFM analysis.

(c) Page 11 of the relief request, second paragraph, states in part that Therefore, the OCJ for PVNGS Unit 1 pressurizer lower shell temperature nozzle further evaluates the

primary stress limits of the repaired configuration considering a final flaw depth and width for fatigue plus corrosion flaw growth through the next cycle Provide the final flaw depth and width through the next cycle. If the flaw depth and width through the next cycle is not available, discuss the initial flaw depth and width assumed in the flaw evaluation.

3. Page 11 of the relief request, section C paragraph, states, in part, that Therefore, the OCJ for PVNGS Unit 1 pressurizer lower shell temperature nozzle further evaluates the primary stress limits of the repaired configuration considering a final flaw depth and width for fatigue plus corrosion flaw growth through the next cycle. To evaluate the requirement, article NB-3228.1 of Section III of the ASME Code is utilized. Discuss whether the proposed repair satisfy NB-3228.1 for one fuel cycle of operation.

4. Related to page 11 of the relief request, section E, Corrosion Evaluation, provide additional information that supports the conclusion that the preliminary corrosion evaluation demonstrates that corrosion will not affect the operation of the proposed repair for one fuel cycle of operation.

5. Related to pages 11 and 12 of the relief request, section F, Loose Parts Evaluation, provide additional information that supports the conclusion that the preliminary loose parts evaluation will not affect the operation of the proposed repair for one fuel cycle of operation.

6. Section 5.E of the relief request discusses, in part, that the repair will result in the pressurizer low alloy steel being exposed to the reactor coolant, which implies that the corrosion evaluation will be performed for what can be described as current Leak Path 2 based upon the repair sketch in Figure 2. If the primary water stress corrosion cracking is caused by Potential Leak Path 1 (as defined in Figure 1A on Page 4 of Relief Request 70), discuss whether roll expanding the alloy 690 outer sleeve in the penetration bore would be sufficient to inhibit continued leakage or will the corrosion evaluation include an analysis of Leak Path 1 along with the potential for corrosion caused by the exposed alloy steel of the pressurizer?

Please note that we sent you draft RAIs on October 24, 2023, and held a clarification call on October 25, 2023. Based on this clarification call, the above RAIs have been finalized. To support verbal authorization, please provide your responses as early as possible.

If you have any questions, please feel free to contact me.

Thank you.

Siva P. Lingam U.S. Nuclear Regulatory Commission Project Manager Palo Verde Nuclear Generating Station, Units 1, 2, and 3 Grand Gulf Nuclear Station Entergy Fleet Location: O-9E22; Mail Stop: O-9E03 Telephone: 301-415-1564

E-mail address: Siva.Lingam@nrc.gov Hearing Identifier: NRR_DRMA Email Number: 2287 Mail Envelope Properties (SJ0PR09MB61094A57F5FDEF644FE98D79F6DEA)

Subject:

Palo Verde, Unit 1 - RAIs for Relief Request 70, Proposed Alternatives for Pressurizer Lower Shell Temperature Nozzle (EPID L-2023-LLR-0057)

Sent Date: 10/25/2023 12:29:24 PM Received Date: 10/25/2023 12:29:00 PM From: Siva Lingam Created By: Siva.Lingam@nrc.gov Recipients:

"Jennifer Dixon-Herrity" <Jennifer.Dixon-Herrity@nrc.gov>

Tracking Status: None "Matthew Mitchell" <Matthew.Mitchell@nrc.gov>

Tracking Status: None "Angie Buford" <Angela.Buford@nrc.gov>

Tracking Status: None "John Tsao" <John.Tsao@nrc.gov>

Tracking Status: None "Eric Reichelt" <Eric.Reichelt@nrc.gov>

Tracking Status: None "Steven Levitus" <Steven.Levitus@nrc.gov>

Tracking Status: None "Carl.Stephenson@aps.com" <Carl.Stephenson@aps.com>

Tracking Status: None "Matthew.Cox@aps.com" <Matthew.Cox@aps.com>

Tracking Status: None "Michael.Dilorenzo@aps.com" <Michael.Dilorenzo@aps.com>

Tracking Status: None Post Office: SJ0PR09MB6109.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 5844 10/25/2023 12:29:00 PM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: