ML23118A165

NRR E-mail Capture - Request for Additional Information Quad Cities, Unit 2, Alternative Request I6R-11

ML23118A165
Person / Time
Site:	Quad Cities
Issue date:	04/28/2023
From:	Robert Kuntz NRC/NRR/DORL/LPL3
To:	Steinman R Exelon Generation Co
References
Download: ML23118A165 (3)

Text

From: Robert Kuntz Sent: Friday, April 28, 2023 10:56 AM To: rebecca.steinman@constellation.com

Subject:

Request for Additional Information RE: Quad Cities, Unit 2, Alternative Request I6R-11 Ms. Steinman, By letter dated April 24, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23114A378), Constellation Energy Generation, LLC (CEG),

submitted alternative I6R-11 which requested approval of proposed alternatives for examination requirements for repairs of the reactor pressure vessel head to shell flanges at Quad Cities Nuclear Power Station (QCNPS) Unit 2. The Nuclear Regulatory Commission (NRC) staff has determined that additional information is required to complete its review. The following is the NRC staffs request for additional information (RAI). During a clarification call held April 28, 2023 a response date of May 1, 2023 was agreed upon. Based on the discussion during the clarification, the request was modified to provide clarification. The Request in the Draft RAI stated: Provide additional information (e.g., schematic drawings, diagrams, photographs, and/or description) regarding how thickness, geometry, and orientation of the reactor vessel flanges prevent volumetric examinations. Discuss the maximum extent to which the volumetric and surface examinations of the mating surfaces between the reactor pressure vessel head and shell flanges can be performed in accordance with Code Case N-638-10, Paragraph 4(a)(2);

provide any assessment of the hardship or impracticality associated with performance of NDE required by code. If CEG cannot provide a response as agreed upon contact me to discuss. If you have any questions contact me.

Robert Kuntz Senior Project Manager NRC/NRR/DORL/LPL3 (301) 415-3733 REQUEST FOR ADDITIONAL INFORMATION ALTERNATIVE REQUEST I6R-11 PROPOSED ALTERNATIVES FOR A TEMPER BEAD WELD REPAIR OF THE MATING SURFACES OF THE REACTOR PRESSURE VESSEL HEAD AND SHELL FLANGES CONSTELLATION ENERGY GENERATION, LLC QUAD CITIES NUCLEAR POWER STATION, UNIT 2 DOCKET NO. 50-265 BACKGROUND By letter dated April 24, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23114A378), Constellation Energy Generation, LLC (CEG),

submitted alternative I6R-11 which requested approval of proposed alternatives for examination requirements for repairs of the reactor pressure vessel head to shell flanges at Quad Cities Nuclear Power Station (QCNPS) Unit 2. Alternative request I6R-11 specifically pertains to the planned weld repair(s) using ambient temperature temper bead (ATTB) welding in accordance with the requirements of American Society of Mechanical Engineers (ASME) Code Case N-638-10. As an alternative to performing the required nondestructive examinations (NDE) at least 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the completion of the third tempering layer, CEG proposes performing the NDE after completion of the repair(s). CEG is also requesting an alternative to the requirement to perform a volumetric examination of the welded region(s).

REGULATORY BASIS QCNPS implements ASME Code Case N-638-10 Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW [gas tungsten arc welding] Temper Bead Technique,Section XI, Division 1 within the stations sixth interval inservice inspection (ISI) Program. Code Case N-638-10 is approved in Regulatory Guide (RG) 1.147, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, Revision 20, Table 1. This Code Case is an approved alternative to ASME Code,Section XI, IWA-4400 to use an automatic or machine gas GTAW temper bead technique to repair certain materials.

The proposed repair(s) will be performed by using ATTB welding in accordance with ASME Code Case N-638-10. Paragraph 4(a)(2), of Code Case N-638-10 requires the final NDE be performed 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> after the completion of the third tempering layer.

In accordance with Code Case N-638-10, Paragraph 4(a)(2), examination of the welded region shall include both volumetric and surface examination methods.

RAI-1

REQUEST Provide additional information (e.g., schematic drawings, diagrams, photographs, and/or description) regarding how thickness, geometry, and orientation of the reactor vessel flanges prevent volumetric examinations.

Discuss the maximum extent to which the volumetric and surface examinations of the mating surfaces between the reactor pressure vessel head and shell flanges can be performed in accordance with Code Case N-638-10, Paragraph 4(a)(2); provide an assessment of how the proposed alternative will result in an acceptable level of quality and safety comparable to performance of the NDE required by code.

Hearing Identifier: NRR_DRMA Email Number: 2062 Mail Envelope Properties (SA9PR09MB4640C7401332C160727E9083996B9)

Subject:

Request for Additional Information RE Quad Cities, Unit 2, Alternative Request I6R-11 Sent Date: 4/28/2023 10:56:23 AM Received Date: 4/28/2023 10:56:00 AM From: Robert Kuntz Created By: Robert.Kuntz@nrc.gov Recipients:

"rebecca.steinman@constellation.com" <Rebecca.Steinman@constellation.com>

Tracking Status: None Post Office: SA9PR09MB4640.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 4645 4/28/2023 10:56:00 AM Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: