ML26012A296
| ML26012A296 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 01/28/2026 |
| From: | Mark Franke NRC/RGN-II/DORS/PB3 |
| To: | Coleman J Southern Nuclear Company |
| References | |
| EAF-RII-2025-0162 IR 2025010 | |
| Download: ML26012A296 (0) | |
Text
EAF-RII-2025-0162 Jamie Coleman Regulatory Affairs Director Southern Nuclear Company, Inc.
3535 Colonnade Parkway Birmingham, AL 35243
SUBJECT:
VOGTLE ELECTRIC GENERATING PLANT, UNITS 1 AND 2 - BIENNIAL PROBLEM IDENTIFICATION AND RESOLUTION INSPECTION REPORT 05000424/2025010 AND 05000425/2025010, WITHDRAWAL OF DISPUTED NON-CITED VIOLATION
Dear Jamie Coleman:
On June 20, 2025, the U.S. Nuclear Regulatory Commission (NRC) issued the subject inspection report documenting a non-cited violation (NCV) associated with the failure to maintain qualification of the emergency diesel generator governor speed control system, NCV 05000424,05000425/2025010-01 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML25167A082).
On July 18, 2025, you provided a response (ADAMS Accession No. ML25199A237) contesting the NCV. On August 15, 2025, the NRC acknowledged receipt of your response (ADAMS Accession No. ML25227A101) and informed you that we would evaluate your response and provide you with the results of our evaluation.
We conducted a detailed review of your response and the applicable regulatory requirements, in accordance with Section 2.8 of the NRCs Enforcement Manual. The staff documented this in the attached enclosure. The NRC staff who performed the review were not involved with the original inspection effort. After careful consideration and deliberation, the NRC staff determined that Institute of Electrical and Electronic Engineers (IEEE) Standard 323-1974 provides a wide range of options and flexibility for the qualification of Class 1E components. Although the NRC staff did not reach agreement on whether the licensees documentation supporting the removal of EMI components was sufficient to meet IEEE Std. 323-1974, the NRC concluded that further deliberation on this issue would not effectively or efficiently serve the Agencys mission, given its very low safety significance. As such, the NRC decided to withdraw NCV 05000424,05000425/2025010-01. We will revise and reissue Biennial Problem Identification and Resolution inspection Report 05000424, 05000425/2025010 to reflect this change to the violation.
January 28, 2026
J. Coleman 2
This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations 2.390, Public Inspections, Exemptions, Requests for Withholding.
Sincerely, Mark E. Franke, Director Division of Operating Reactor Safety Docket Nos. 05000424 and 05000425 License Nos. NPF-68 and NPF-81
Enclosure:
NRC Evaluation of Licensee Response to Non-Cited Violation cc w/ encl: GovDelivery Subscriber Signed by Franke, Mark on 01/28/26
SUNSI Review X
Non-Sensitive
Sensitive X
Publicly Available
Non-Publicly Available OFFICE RII/DORS RII/ACES OE NRR/DRO RII-RC RII/DORS NAME C. Scott B. Desai J. Peralta D. Aird S. Price M. Franke DATE 1/12/26 1/12/26 1/27/26 1/27/26 1/26/26 1/28/26
Enclosure NRC EVALUATION OF LICENSEE RESPONSE TO NON-CITED VIOLATION
Background
On June 20, 2025, the U.S. NRC issued Inspection Report (IR) 05000424, 425/2025010 that included a non-cited violation (NCV) of Title 10 of the Code of Federal Regulations (10 CFR)
Part 50, Appendix B, Criterion III, Design Control, associated with the failure to maintain qualification of the emergency diesel generator (EDG) governor speed control system, NCV 05000424,05000425/2025010-01 (ADAMS Accession No. ML25167A082). In a \
letter dated July 18, 2025 (ADAMS Accession No. ML25199A237), Southern Nuclear Operating Company, Inc (SNC) contested the NCV and provided its position that Vogtle Electric Generating Plant, Units 1 & 2 (Vogtle) complied with regulatory requirements for demonstrating adequate electromagnetic compatibility (EMC) of its EDG governor speed control system.
Restatement of NCV 05000424/425/2025010-01 Violation: 10 CFR 50 Appendix B, to 10 CFR Part 50, Criterion III, Design Control, requires, in part, that design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, using alternate or simplified calculational methods, or by the performance of a suitable testing program.
Updated Safety Analysis Report (USAR), Section 8.1.4.3, Design Criteria, Regulatory Guides, and IEEE Standards, establishes that the design of the offsite power and onsite Class 1E electric systems conforms with IEEE 323-1974, Qualifying Class 1E Equipment for Nuclear Power Generating Stations.
IEEE 323-1974, Qualifying Class 1E Equipment for Nuclear Power Generating Stations specified that qualification must demonstrate the acceptable performance of Class 1E components; to the range of voltage, frequency, load, electromagnetic interference, and other electrical characteristics.
Licensee Procedure SN9604 SNC - Standard Specification Electromagnetic Interference (EMI)
Qualification Requirements for Southern Nuclear Power Plant Equipment, Section 4.1.3, states in part that "differences that are not conservative may require additional testing. All new testing specified should conform to the requirements of this specification (SN9604). However, an evaluation of differences may be acceptable as long as it can be shown that an adequate EMC margin exists.
Contrary to the above, since March 2023, the licensees design control measures failed to verify that the installation of EDG governor components in a configuration different from the EMI qualification test was acceptable. Specifically, the licensee failed to verify that adequate EMC margin was maintained, as required by SN9604, after EDG governor components were installed without mitigating devices used to qualify the EDG governor. This impacted the EDGs reliability and exposed the EDGs to failures due to electromagnetic interferences.
Summary of Licensees Response In its response dated July 18, 2025, SNC specifically refuted two points identified in NRC NCV 2025010-01:
2
- 1) NRC IR 05000424, 425/2025010 Statement: The licensee anticipated the location of the governor panel, and its construction would provide shielding. However, the licensee has not demonstrated this through testing, nor do they have an evaluation that has quantified the impact of the overall plant emissions level after installation.
SNCs Response: There is no regulatory requirement, self-imposed requirement, or industry requirement to quantify the overall plant specific emissions levels, nor is there a requirement to perform specific testing to quantify the impact on overall plant emissions levels post-installation in SNC Specifications (X4AK01, Rev. 8, X4AK01A, Rev. 4), EPRI Technical Report TR-102323 Rev. 3, or the IEEE Standard 323-1974.
- 2) NRC IR 05000424, 425/2025010 Statement: The licensee's evaluation did not verify that installation of EDG governor components in a configuration different from the EMI qualification test did not increase the overall plant emissions level to demonstrate adequate EMC margin and provide reasonable assurance of EMC.
SNCs Response: SNC's evaluation documented in DOEJ-VDSNC953980-J001 did verify the installation of EDG governor components in a configuration different from the EMI qualifications test, ensuring no increase to the overall plant emissions level and adequate EMC. While an EMI specification wasn't included when the EDG was originally procured, SNC insisted on EMI testing and evaluation for the replacement components based on design attribute considerations in industry procedure IP-ENG- 001. The EMI testing and evaluation, performed by ESI, adhered to specification SN9604-002 and IEEE Std 323-1974 Section 6.8.
As stated above, there is no requirement to evaluate the overall plant EMI emission levels, and the industry guidance, specifically IEEE Std 323-1974 Section 6.8 and EPRI TR-102323, Rev. 3, focus on ensuring adequate EMC through acceptable methods such as type testing, operating experience, and analysis, rather than mandating specific emission level evaluations. SNC's evaluation of the modifications was performed with the oversight from internal and external experts to ensure compliance with industry standards and provide a basis that adequate EMC margin existed.
NRCs Evaluation The NRC staff performed an independent review of the licensees position as described in its \
July 18, 2025, letter. Additionally, the staff discussed SNCs response with Office of Nuclear Reactor Regulation (NRR) subject matter experts familiar with design control regulations, IEEE Std 323-1974 requirements, and electromagnetic compatibility testing to gain valuable perspective on the evaluation of Vogtles implementation of EMC for the EDG governor speed control system. The NRC staff reviewed the following documents:
10 CFR 50, Appendix B, Criterion III, Design Control; Institute of Electrical and Electronics Engineers Standard (IEEE Std.) 323-1974, IEEE Standard for Qualifying Class 1E Equipment for Nuclear Power Generating Stations; Electric Power Research Institute (EPRI) TR-102323, Guidelines for Electromagnetic Interference Testing at Power Plants; and SNC procedure SN-9604, Electromagnetic Interference (EMI) Qualification Requirements for Southern Nuclear Power Plant Equipment;
3 DOEJ-VDSNC953980-J001 - Electromagnetic Compatibility Evaluation for Plant Use of Woodward 2301A Speed Control System DOEJ-VDSNC953976-J001 - Electromagnetic Compatibility Evaluation for Plant Use of Woodward 2301A Speed Control System AMS Report Number ESI220802R0-F - Test Report EMC Qualification Testing of a Governor Speed Control System for Engine Systems Inc With respect to the two specific points disputed by SNC, the NRC agrees that there is no regulatory requirement to perform specific testing to quantify the impact on overall plant emissions levels post-installation. The NRC also acknowledges that IEEE Std. 323-1974, SNC specification SNC9604, and EPRI TR-102323 do not explicitly require quantification of overall plant emissions levels post-installation. The NRC does not dispute that the original qualification testing adhered to IEEE Std. 323-1974 and licensee procedure SN9604.
Vogtles USAR specifies that Class 1E electrical equipment will be qualified in accordance with IEEE Std. 323-1974. This standard applies to the EDG governor speed control system as it is part of the Class 1E electrical system at Vogtle. The violation was based on the fact that the EDG governor system was originally qualified with EMI mitigation components, including capacitors, ferrite beads, and snubbers, to meet the qualification standards in IEEE Std. 323-1974. However, the licensee subsequently removed these components during post-maintenance testing, which raised concerns among the NRC inspectors regarding whether the as-installed configuration continued to meet the original qualification criteria.
During the Biennial Problem Identification and Resolution inspection (NRC IR 05000424, 05000425/2025010), the NRC staff determined that the licensees evaluation for the removal of the EMI mitigation components, documented in DOEJ-VDSNC953980-J001 and DOEJ-VDSNC953976-J001, did not include sufficient information to fully justify that the removal of the EMI mitigation equipment did not impact the results of the original qualification testing documented in AMS Report Number ESI220802R0-F. Therefore, the NRC concluded that SNC had not demonstrated EMI qualification of the modified EDG governor in accordance with IEEE Std. 232-1974, Section 6.2, which states that the qualification of Class 1E equipment shall include the range of voltage, frequency, load, and EMI, and other electrical characteristics.
The NRCs independent review identified other sections of IEEE Std. 232-1974 applicable to this issue. Specifically, Section 4 states that qualification may be accomplished in several ways: type testing, operating experience, or analysis. These may be used individually or in any combination depending upon the particular situation, and that for analysis to include justification of methods, theories, and assumptions used. Equally important, Section 6.8, Modifications, states, in part, that modifications should not be made to the equipment, or to the equipment or test specifications, after the start of the type test or beginning of the operating experience reporting period since such modification will normally render the test and experience results inconclusive. Modifications may be made only if full justification is documented on the basis that such modifications have no bearing on the validity of the test.
After careful consideration and deliberation, the NRC staff determined that IEEE Std. 323-1974 provides a wide range of options and flexibility for the qualification of Class 1E components.
Although the NRC staff did not reach agreement on whether the licensees documentation supporting the removal of EMI components was sufficient to meet IEEE Std. 323-1974, the NRC concluded that further deliberation on this issue would not effectively or efficiently serve the Agencys mission, given its very low safety significance. As such, the NRC has decided to withdraw the violation.
4 NRC Conclusion The NRC staff concluded that the NCV documented in Inspection Report 05000424, 05000425/2025010 will be withdrawn. This determination is based on the very low safety significance of the issue and the conclusion that expending the additional resources required to achieve full resolution would not be in the agencys interest. The NRC will revise and reissue NRC Inspection Report 05000424, 05000425/2025010 to reflect this change.