ULNRC-06910, Updated Framatome Reports to Resolve License Renewal Commitments 34 and 35 - Perform Evaluation of Crack Initiation and Propagation in Steam Generator Divider Plate and Tube-To-Tubesheet Welds
| ML24347A226 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 12/12/2024 |
| From: | Elwood T Ameren Missouri, Union Electric Co |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| Shared Package | |
| ML24347A225 | List: |
| References | |
| ULNRC-06910 | |
| Download: ML24347A226 (1) | |
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.t Callaway Plant 8315 County Road 459 : Steedman, MO 65077 : AmerenMissouri.com
.t December 12, 2024 ULNRC-06910 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Ladies and Gentlemen:
DOCKET NUMBER 50-483 CALLAWAY PLANT UNIT 1 UNION ELECTRIC CO.
RENEWED FACILITY OPERATING LICENSE NPF-30 UPDATED FRAMATOME REPORTS TO RESOLVE CALLAWAY PLANT LICENSE RENEWAL COMMITMENTS 34 AND 35 - PERFORM EVALUATION OF CRACK INITIATION AND PROPAGATION IN STEAM GENERATOR DIVIDER PLATE AND TUBE-TO-TUBESHEET WELDS
References:
Provided on Page 3.
By letter (Reference 1) and attachment (Reference 2) dated December 5, 2024, Ameren Missouri submitted to the U.S. Nuclear Regulatory Commission (NRC), supplemental information related to Commitment Nos. 34 and 35 of the Callaway Plant License Renewal (LR) safety evaluation report (Reference 3). In that letter and its attachment, Callaway committed to provide, at a later date, revisions of Framatome reports that were initially submitted on December 20, 2023 via Reference 5 and 6. Accordingly, the purpose of this letter is to submit the revised Framatome reports.
includes a revision to the cracking assessment for the Framatome replacement steam generator (RSG) channel head assembly (Reference 5). This Framatome report was updated to address NRC audit questions (Reference 4), as described in Reference 2 and noted in the Calculation Summary Sheet and Record of Revision sections in Enclosure 1. Specifically, the cracking assessment was revised to clarify that testing was performed to verify the RTNDT value (i.e., reference nil ductility temperature). Secondly, the residual stress assumption was clarified to state that, at the clad-base metal interface, the residual stress is an uncertainty, not a magnitude as previously stated. The typographical errors for the heat transfer coefficient (HTC) unit were corrected. Finally, information was added to explain the stress path lines for the crack growth analysis.
includes a revision to the Framatome's Callaway tube-to-tubesheet welding report (Reference 6). This report was updated to indicate the chromium content and compressive stress
ULNRC-06910 December 12, 2024 Page 2 of 5 requirements for the tube-to-tubesheet weld aging management approach, as described in Reference 2 and noted in the Nature of Change section of Enclosure 2.
This letter does not contain new commitments. If there are any questions, please contact Thomas Elwood at 314-225-1905.
Sincerely, Thomas B. Elwood Manager, Regulatory Affairs ESS, Cracking Assessment for Framatome Replacement Steam Generator (RSG) Channel Head Assembly, Revision 2, Callaway Tube to Tubesheet Welding Report, Revision 1
ULNRC-06910 December 12, 2024 Page 3 of 5
References:
- 1. Ameren Missouri letter ULNRC-06907, "Callaway, Unit 1, Supplementation Information and Response to Request for Confirmation of Information (RCI) to Resolve Callaway Plant License Renewal Commitments 34 and 35 - Perform Evaluation of Crack Initiation and Propagation in Steam Generator Divider Plate and Tube-to-Tubesheet Welds," dated December 5, 2024 (ADAMS Accession No. ML24340A121)
- 2. Attachment to Ameren Missouri letter ULNRC-06907, "Callaway, Unit 1, Supplemental Information and Response to Request for Confirmation of Information (RCI) for Resolution of Callaway Plant License Renewal Commitments 34 and 35," dated December 5, 2024 (ADAMS Accession No. ML24340A122)
- 3. NUREG-2172, "Safety Evaluation Report Related to the License Renewal of Callaway Plant, Unit 1," dated March 2015 (ADAMS Accession No. ML15068A342)
- 4. NRC letter, "Callaway Plant, Unit 1 - Regulatory Audit Questions for License Renewal Commitments 34 and 35 (EPID L-2024-LRO-0009) - Non-Proprietary," dated September 11, 2024 (ADAMS Accession No. ML24247A304)
- 5. Enclosure 1 of Ameren Missouri letter ULNRC-06849, "Callaway, Unit 1, Cracking Assessment for Framatome RSG Channel Head Assembly," dated December 20, 2023 (ADAMS Accession No. ML23354A246)
- 6. Enclosure 2 of Ameren Missouri letter ULNRC-06849, "Callaway, Unit 1, Tube to Tubesheet Welding Report," dated December 20, 2023 (ADAMS Accession No. ML23354A247)
ULNRC-06910 December 12, 2024 Page 4 of 5 cc:
Mr. John Monninger Regional Administrator U. S. Nuclear Regulatory Commission Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. M. Chawla Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop O8B1A Washington, DC 20555-0001
ULNRC-06910 December 12, 2024 Page 5 of 5 Index and send hardcopy to QA File A160.0761 Hardcopy:
Certrec Corporation 6500 West Freeway, Suite 400 Fort Worth, TX 76116 (Certrec receives ALL attachments as long as they are non-safeguards and may be publicly disclosed.)
Electronic distribution for the following can be made via Responses and Reports ULNRC Distribution:
F. M. Diya K. C. Scott T. M. Hart J. G. Beck T. A. Witt T. B. Elwood NSRB Secretary STARS Regulatory Affairs Mr. Jay Silberg (Pillsbury Winthrop Shaw Pittman LLP)