ML23139A080
| ML23139A080 | |
| Person / Time | |
|---|---|
| Site: | Comanche Peak  |
| Issue date: | 05/18/2023 |
| From: | Dennis Galvin NRC/NRR/DORL/LPL4 |
| To: | Hicks J Vistra Operations Company |
| References | |
| L-2023-LLA-0058 | |
| Download: ML23139A080 (5) | |
Text
From: Dennis Galvin Sent: Thursday, May 18, 2023 5:44 PM To: Jack Hicks (Jack.Hicks@luminant.com)
Cc: ryan.sexton@vistracorp.com
Subject:
Comanche Peak - Draft Supplemental Information Request - License Amendment Request Regarding General Design Criterion 5 of Appendix A to 10 CFR Part 50 and Regulatory Guide 1.81 (EPID L-2023-LLA-0058)
Attachments: Comanche Peak - Compliance Regarding GDC 5 RG 1.81 LAR - Draft Supplemental Request Issued 2023-05-18 for Licensee.pdf
Dear Mr. Hicks,
By letter dated April 20, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23110A156, Vistra Operations Company LLC (Vistra OpCo, the licensee) submitted a license amendment request (LAR) for Comanche Peak Nuclear Power Plant (Comanche Peak, CPNPP), Unit Nos. 1 and 2, regarding changes to the Final Safety Analysis Report (FSAR). Specifically, the proposed amendments would allow a deviation in compliance to Regulatory Guide (RG) 1.81, Revision 1, Shared Emergency and Shutdown Electric Systems for Multi-Unit Nuclear Power Plants (ML003740343) to meet the regulatory requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and Utilization Facilities, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion (GDC) 5, Sharing of structures, systems, and components, and address the violation issued in the Comanche Peak Integrated Inspection Report dated November 1, 2022 (ML22299A056). To support the proposed amendment, the licensee proposed FSAR changes to provide additional description of the power feeds to some common 125 volts direct current (VDC) and 118 volts alternating current (VAC) safety-related electrical buses, which can be fed from both units and also feeds some Unit 1 specific loads.
The licensee also submitted Technical Specifications (TSs) Bases changes (mark-up) necessary to account for changes in the FSAR.
To complete its review, the NRC staff has prepared the attached supplemental information request in DRAFT form. To arrange a clarification call and to discuss the due date, please contact me at (301) 415-6256.
Respectfully, Dennis Galvin Project Manager U.S Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing Licensing Project Branch 4 301-415-6256 Docket Nos. 50-445 and 50-446
Hearing Identifier: NRR_DRMA Email Number: 2102 Mail Envelope Properties (SA1PR09MB81117D7AE178BB5AE7AB2F2CFB7F9)
Subject:
Comanche Peak - Draft Supplemental Information Request - License Amendment Request Regarding General Design Criterion 5 of Appendix A to 10 CFR Part 50 and Regulatory Guide 1.81 (EPID L-2023-LLA-0058)
Sent Date: 5/18/2023 5:43:52 PM Received Date: 5/18/2023 5:43:00 PM From: Dennis Galvin Created By: Dennis.Galvin@nrc.gov Recipients:
"ryan.sexton@vistracorp.com" <ryan.sexton@vistracorp.com>
Tracking Status: None "Jack Hicks (Jack.Hicks@luminant.com)" <Jack.Hicks@luminant.com>
Tracking Status: None Post Office: SA1PR09MB8111.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 1944 5/18/2023 5:43:00 PM Comanche Peak - Compliance Regarding GDC 5 RG 1.81 LAR - Draft Supplemental Request Issued 2023-05-18 for Licensee.pdf 196242 Options Priority: Normal Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:
DRAFT SUPPLEMENTAL INFORMATION NEEDED LICENSE AMENDMENT REQUEST REGARDING GENERAL DESIGN CRITERION 5 OF APPENDIX A TO 10 CFR PART 50 AND REGULATORY GUIDE 1.81 VISTRA OPERATIONS COMPANY LLC COMANCHE PEAK NUCLEAR POWER PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-445 AND 50-446 By letter dated April 20, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23110A156, Vistra Operations Company LLC (Vistra OpCo, the licensee) submitted a license amendment request (LAR) for Comanche Peak Nuclear Power Plant (Comanche Peak, CPNPP), Unit Nos. 1 and 2, regarding changes to the Final Safety Analysis Report (FSAR). Specifically, the proposed amendments would allow a deviation in compliance to Regulatory Guide (RG) 1.81, Revision 1, Shared Emergency and Shutdown Electric Systems for Multi-Unit Nuclear Power Plants (ML003740343) to meet the regulatory requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and Utilization Facilities, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion (GDC) 5, Sharing of structures, systems, and components, and address the violation issued in the Comanche Peak Integrated Inspection Report dated November 1, 2022 (ML22299A056). To support the proposed amendment, the licensee proposed FSAR changes to provide additional description of the power feeds to some common 125 volts direct current (VDC) and 118 volts alternating current (VAC) safety-related electrical buses, which can be fed from both units and also feeds some Unit 1 specific loads.
The licensee also submitted Technical Specifications (TSs) Bases changes (mark-up) necessary to account for changes in the FSAR.
The U.S. Nuclear Regulatory Commission (NRC) staff has identified that the following information is needed to begin its technical review.
Regulatory Requirements Appendix A, to 10 CFR Part 50, GDC 5, states that:
Structures, systems, and components important to safety[, including the onsite electric power supplies and distribution systems,] shall not be shared among nuclear power units unless it can be shown that such sharing will not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cooldown of the remaining units.
The regulations in 10 CFR 50.36, Technical specifications, establish the requirements related to the content of the TS. Pursuant to 10 CFR 50.36(c), TS are required to include items in five specific categories related to station operation: (1) safety limits, limiting safety system settings, and limiting control settings, (2) limiting conditions for operation, (3) surveillance requirements, (4) design features; and (5) administrative controls.
Enclosure
The regulation, 10 CFR 50.36(a)(1), states that:
Each applicant for a license authorizing operation of a production or utilization facility shall include in his application proposed technical specifications in accordance with the requirements of this section. A summary statement of the bases or reasons for such specifications, other than those covering administrative controls, shall also be included in the application, but shall not become part of the technical specifications.
Supplemental Information Required
- 1. In the FSAR markup in attachment 1 of the enclosure to the LAR, the licensee provided the following justification corresponding to Regulatory Position C.2.d in RG 1.81 (the NRC staff notes the description of the FSAR change in section 2.3 of the enclosure to the LAR uses somewhat different wording):
For AC [alternating current] electric systems, CPNPP has created the following administrative procedural requirement for XEC1-1 and XEC2-1, which power some Unit 1 safety-related loads, that the power source SHALL be aligned to Unit 1 during Unit 1 Modes 1 through 6. The panels power source alignment to Unit 2 will only be allowed when Unit 1 is in NO MODE. Since they only power Unit 1 loads this will not allow any interaction. This requirement is being added to the FSAR, a markup of the FSAR is included in Attachment 1 to this letter.
For DC [direct current] electric systems XED1-1 and XED2-1, feed both Unit 1 and common components. Alignment to either unit provides an acceptable power source for Unit 1 components fed from the panels. An evaluation of being aligned from a Unit 2 power source coincident with a Unit 1 SI [safety injection] signal did not reveal any adverse impacts (i.e., no significant loss of safety function was identified). Evaluations confirmed that the power sources, from both units, feeding the common buses have sufficient capacity and capability to adequately feed all the common bus loads, as stated in the FSAR.
The LAR did not include the evaluations mentioned in the proposed FSAR. These are needed for the NRC staff to evaluate that the sharing of the above-mentioned AC and DC common buses would not significantly impair their ability to perform their safety functions, including, in the event of an accident in one unit, an orderly shutdown and cool down of the remaining unit.
(1) Provide an evaluation that provides the basis for the procedural requirement for 118 VAC buses XEC1-1 and XEC2-1, which power some Unit 1 safety-related loads, that the power source SHALL be aligned to Unit 1 during Unit 1 Modes 1 through 6. The power source alignment for these buses to Unit 2 will only be allowed when Unit 1 is in NO MODE.
(2) Provide an evaluation that provides the basis that the 125 VDC buses the XED1-1 and XED2-1, which power some Unit 1 safety-related loads, the aligned from a Unit 2 power source coincident with a Unit 1 SI signal will not have any adverse impacts (i.e., no significant loss of safety function was identified).
(3) In the markup of FSAR changes in attachment 1 of the enclosure to the LAR, as stated above, the following statement This requirement is being added to the FSAR, a markup of the FSAR is included in Attachment 1 to this letter should not be a part of markup.
Please provide revised markup without this sentence.
(4) Revise the applicable description to ensure consistency between the description of the FSAR change in section 2.3 of the enclosure to the LAR and the FSAR markup in attachment 1 to the LAR.
Other Issues Identified during the Acceptance Review Although not required for the NRC to complete its acceptance review, the NRC staff has identified some initial information required to complete its review as follows. The response may be submitted with the responses to a supplemental request or separately (e.g., with responses to requests for additional information, if they are identified).
- 1. The TS Bases should reflect the design basis in the FSAR. TS Bases table B 3.8.9-1 does not currently list all the safety-related buses, including the common buses clarified in the LAR. The listing of all the safety-related buses in TS Bases table B 3.8.9-1 is considered necessary to meet the intent of TS 3.8.9.
Provide updated TS Bases table B 3.8.9-1 with additions of common 125 VDC buses XED1-1 and XED2-1, and common 118 VAC buses XEC1-1 and XEC2-1, to their train A and train B assignments. In addition, all other safety-related buses (such as 480 VAC motor control centers buses) to which safety-related loads are connected should also be added to the table B 3.8.9-1.