ML26056A177
| ML26056A177 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood  (NPF-037, NPF-066, NPF-072, NPF-077) |
| Issue date: | 03/02/2026 |
| From: | Scott Wall NRC/NRR/DORL/LPL3 |
| To: | Mudrick C Exelon Generation Co |
| Wall, S | |
| References | |
| EPID L 2025 LLA0172 | |
| Download: ML26056A177 (0) | |
Text
March 2, 2026 Mr. Christopher H. Mudrick Sr.
Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Officer Constellation Nuclear 200 Energy Way Kennett Square, PA 19348
SUBJECT:
BRAIDWOOD STATION, UNITS 1 AND 2, AND BYRON STATION, UNIT NOS. 1 AND 2 - AUDIT
SUMMARY
FOR LICENSE AMENDMENT REQUEST TO REVISE METHODOLOGY SUPPORTING THE USE OF FRAMATOME GAIA FUEL (EPID L-2025-LLA0172)
Dear Mr. Mudrick:
By letter dated November 12, 2025 (Agencywide Documents Access and Management System (ADAMS) Package Accession No. ML25318B206), Constellation Energy Generation, LLC (the licensee), submitted a license amendment request (LAR) for Braidwood Station, Units 1 and 2 (Braidwood), and Byron Station, Unit Nos. 1 and 2 (Byron), to the U.S. Nuclear Regulatory Commission (NRC). The proposed LAR would modify the methodology previously approved for Braidwood and Byron to transition to Framatome GAIA fuel.
To support its review, by letter dated December 15, 2025 (ML25342A113), the NRC staff notified the licensee that they would conduct a regulatory audit through an online portal (also known as electronic portal, ePortal, electronic reading room) established by the licensee. The regulatory audit summary is enclosed with this letter.
If you have any questions, please contact me at (301) 415-2855, or by e-mail at Scott.Wall@nrc.gov.
Sincerely,
/RA/
Scott P. Wall, Senior Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. STN 50-454, STN 50-455, STN 50-456, and STN 50-457
Enclosure:
Regulatory Audit Summary cc: Listserv
Enclosure REGULATORY AUDIT
SUMMARY
REGARDING LICENSE AMENDMENT REQUEST TO MODIFY METHODOLOGY SUPPORTING UTILIZING FRAMATOME GAIA FUEL BRAIDWOOD STATION, UNITS 1 AND 2, AND BYRON STATION, UNIT NOS. 1 AND 2 CONSTELLATION ENERGY GENERATION, LLC.
DOCKET NOS. STN 50-454, STN 50-455, STN 50-456, AND STN 50-457
1.0 BACKGROUND
By letter dated November 12, 2025 (Agencywide Documents Access and Management System Package Accession No. ML25318B206), Constellation Energy Generation, LLC (the licensee),
submitted a license amendment request (LAR) for Braidwood Station, Units 1 and 2 (Braidwood), and Byron Station, Unit Nos. 1 and 2 (Byron). The proposed amendments would modify the methodology previously approved for Braidwood and Byron to transition to Framatome GAIA fuel.
The U.S. Nuclear Regulatory Commission (NRC) staff performed a preliminary review of the LAR and determined that a regulatory audit would assist in the timely completion of the review.
An audit plan was provided to the licensee on December 15, 2025 (ML25342A113), which provided the list of requested documents and other details pertaining to the audit. The purpose of the audit was to gain an understanding of the information needed to support the NRC staffs licensing decision regarding the LAR and to develop requests for additional information (RAIs),
if necessary. The information submitted in support of the LAR is under final review, and any additional information needed to support the LAR review will be formally requested by the NRC staff using the RAI process in accordance with Office of Nuclear Reactor Regulation (NRR)
Office Instruction LIC-101, Revision 6, License Amendment Review Procedures (ML19248C539).
The regulatory audit is a planned license or regulation-related activity that includes the examination and evaluation of primarily non-docketed information. The regulatory audit is conducted with the intent to gain understanding, to verify information, and/or to identify information, that will require docketing to support the basis of a licensing or regulatory decision.
Performing a regulatory audit of the licensees information is expected to assist the NRC staff in efficiently conducting its review or gain insights on the licensees processes or procedures.
Information that the NRC staff relies upon to make the safety determination must be submitted on the docket. However, the NRC staff may review supporting information retained as records under Title 10 of the Code of Federal Regulations (10 CFR) section 50.71, Maintenance of records, making of reports, and/or 10 CFR 54.37, Additional records and recordkeeping requirements, which, although not required to be submitted as part of the licensing action, would help the NRC staff better understand the licensees submitted information.
2.0 SCOPE By letter dated December 15, 2025, the NRC staff issued an audit plan. To support discussions, the NRC staff provided audit questions with items for CEG to clarify. CEG posted answers to these questions to the online portal. The NRC staff held clarification discussions with the CEG staff via Microsoft Teams. All audit questions were discussed. Technical discussions were focused on information supporting the licensees request to modify the methodology previously approved for Braidwood and Byron to transition to Framatome GAIA fuel.
3.0 AUDIT TEAM The NRC audit team included the following:
Scott Wall, Plant Licensing Branch III (LPL3)
Kevin Heller, Nuclear Methods and Fuel Analysis Branch (SFNB)
Robert Beaton, Nuclear Systems Performance Branch (SNSB) 4.0 DOCUMENT AND FILES REVIEWED The NRC staff reviewed the following documents:
Framatome Calculation FS1-0068728, Revision 4.0, Braidwood/Byron Uncontrolled Bank Withdrawal at Power, August 11, 2025.
Framatome calculation FS1-0082746, Revision 1.0, Byron/Braidwood Units 1 and 2 Steam Generator Differences, December 16, 2025.
Framatome calculation FS1-0080831, Revision 1.0, Evaluation of Dittus-Boelter Sampling Range for Byron and Braidwood, October 23, 2025.
Framatome calculation FS1-0069146, Revision 4.0, ARITA Sensitivity Study Handbook, October 8, 2025.
In addition to the documents listed above, the licensee response to the various audit questions was also included on the portal for NRC staff review.
5.0 RESULTS OF THE AUDIT As a result of the audit, the NRC staff gained a better understanding of the licensees analyses and calculations that provide the technical support for the LAR. Several audit questions were provided to the licensee and the licensee provided a supplement to the LAR on February 24, 2026 (ML26055A319).
ML26056A177 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DSS/SFNB/BC NAME SWall SLent SKrepel DATE 02/25/2026 02/25/2026 02/26/2026 OFFICE NRR/DSS/SNSB/BC NRR/DORL/LPL3/BC (A)
NRR/DORL/LPL3/PM NAME NDifrancesco IBerrios SWall DATE 03/02/2026 03/02/2026 03/02/2026