ML24341A027
| ML24341A027 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 01/13/2025 |
| From: | John Klos Plant Licensing Branch II |
| To: | Carr E Virginia Electric & Power Co (VEPCO) |
| Klos, J | |
| References | |
| EPID L-2022-LLA-0167 | |
| Download: ML24341A027 (1) | |
Text
January 13, 2025 Eric S. Carr President - Nuclear Operations and Chief Nuclear Officer Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
SUBJECT:
SURRY POWER STATION, UNITS 1 AND 2 - CORRECTION TO LICENSE AMENDMENTS NOS. 315 AND 315 TECHNICAL SUPPORT CENTER UPDATED VENTILATION DESIGN (EPID L-2022-LLA-0167)
Dear Mr. Carr:
By letter dated November 13, 2024 (Agencywide Document Access and Management Systems (ADAMS) Accession No. ML24318C462), Virginia Electric and Power Company (Dominion Energy Virginia) informed the U.S. Nuclear Regulatory Commission (NRC) of a necessary change to the Surry Power Station (Surry) Units 1 and 2 Technical Support Center (TSC) ventilation system that was realized during implementation of Amendments Nos. 315 and 315, respectively, that were issued by the NRC on November 7, 2023 (ML23242A229).
Specifically, the license amendment request submittals for the amendment stated that a modulated filter fan speed would be utilized for maintaining positive pressure in the TSC at 0.125 inches of water (ML22322A182, Attachment 1, page 13 of 36, dated November 18, 2022);
however, during amendment implementation and TSC ventilation testing, the licensee determined that a fixed filter fan speed would be necessary.
Further, the licensee observed that while the positive pressure value of 0.125 inches of water could be attained, this value could be challenged due to seasonal temperature changes. The licensee further stated that, to prevent outside air infiltration going forward, the TSC positive pressure minimum value has also been revised as follows: the occupied TSC space will be maintained at 0.10 inches of water relative to outside air pressure, and the TSC penthouse, which is not an occupied space, will be maintained at 0.05 inches of water relative to outside air pressure.
In its assessment, the licensee determined that, These changes to the TSC ventilation system do not impact the TSC dose analysis since the dose analysis only assumes the TSC is maintained at a positive pressure. Furthermore, page 18 of the NRC safety evaluation included in TS Amendments 315 and 315 for [Surry Power Station] SPS Units 1 and 2, respectively, states, the licensee states that to limit the infiltration of airborne radioactivity, the TSC emergency ventilation system is designed to provide a filtered makeup air flow rate to maintain the TSC habitability envelope at a positive pressure... This statement remains valid with the updated positive pressure values and fixed fan speed; therefore, the NRCs safety evaluation conclusions are not affected by the TSC ventilation design changes.
The NRC staff has reviewed the licensees analysis provided in its letter dated November 13, 2024, and determined that the licensees proposed corrections do not change any of the technical and regulatory conclusions associated with the issuance of Amendment Nos. 315 and 315, respectively, for Surry, Units 1 and 2, and do not affect the proposed finding that the amendments involve no significant hazards consideration as published in the Federal Register on January 24, 2023, 88 FR 4216. As described in the NRC safety evaluation, further implementation actions are planned to include, an existing hatch between the TSC penthouse and the ground level of the proposed TSC (occupied space) will be permanently sealed with a 12-inch concrete plug to prevent radiation exposure to the occupied TSC space below.
Accordingly, Enclosures 1, to this letter provides 2 corrected TS pages (page 2), and NRC safety evaluation correction pages 1 and 18 (Enclosure 3) for Amendment Nos. 315 and 315, respectively, acknowledging the licensees supplemental analysis from implementation in its letter dated November 13, 2024.
Consistent with NRC staff guidance dated January 16, 1997 (ML103260096), based on the NRCs policy established by SECY-96-238, these errors can be corrected by a letter to the licensee from the NRC staff.
If you have any questions, please contact me at (301) 415-5136, or via email at John.Klos@nrc.gov.
Sincerely,
/RA/
John Klos, Project Manager Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-280 and 50-281
Enclosure:
Corrected errata page and (2) TS page 2s, for Surry Unit 1 and Unit 2 Corrected Safety Evaluation pages 1 and 18 cc: Listserv
SAFETY EVALUATION CORRECTED PAGES VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-280 AND 50-281
- 2.
Accordingly, by Amendment No. 315, Subsequent Renewed Facility Operating License No. DPR-32 is hereby amended to authorize revision to the Emergency Plan for the Surry Power Station, Unit 1, as set forth in Virginia Electric and Power Company (Dominion Energy Virginia) application dated November 18, 2022, as supplemented by letters dated May 31 and August 7, 2023, and November 13, 2024, and evaluated in the NRC staffs safety evaluation dated November 7, 2023.
- 3.
This license amendment is effective as of its date of issuance and shall be implemented within 180 days.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to License No. DPR-32 Date of Issuance: November 7, 2023
- 2.
Accordingly, by Amendment No. 315, Subsequent Renewed Facility Operating License No. DPR-32 is hereby amended to authorize revision to the Emergency Plan for the Surry Power Station, Unit 1, as set forth in Virginia Electric and Power Company (Dominion Energy Virginia) application dated November 18, 2022, as supplemented by letters dated May 31 and August 7, 2023, and November 13, 2024, and evaluated in the NRC staffs safety evaluation dated November 7, 2023.
- 3.
This license amendment is effective as of its date of issuance and shall be implemented within 180 days.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Michael T. Markley, Chief Plant Licensing Branch II-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to License No. DPR-37 Date of Issuance: November 7, 2023
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 315 TO SUBSEQUENT RENEWED FACILITY OPERATING LICENSE NO. DPR-32 AND AMENDMENT NO. 315 TO SUBSEQUENT RENEWED FACILITY OPERATING LICENSE NO. DPR-37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-280 AND 50-281
1.0 INTRODUCTION
By letter dated November 18, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22322A182), as supplemented by letters dated May 31 (ML23167B007) August 7, 2023 (ML23220A148) and, November 13, 2024 (ML24318C462)
Virginia Electric and Power Company (licensee, Dominion) submitted a license amendment request (LAR) to revise the license and Emergency Plan for Surry Power Station (Surry), Units 1 and 2. The proposed change would revise the Surry Emergency Plan (SEP) to allow the relocation of the Technical Support Center (TSC) from its current location adjacent to the Main Control Room (MCR) to a building that was used previously as the Local Emergency Operations Facility (LEOF). The proposed new TSC on the former LEOF is adjacent to the Surry training building on the north side of the Owner Controlled Area but outside of the Protected Area (PA).
This proposed change also removes reference to the MCR as an alternate location for the TSC.
The licensee states that the alternate TSC location is not the same as the alternative facility required by Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix E.IV.E.8.d, which remains unchanged by the proposed amendment. By letter dated November 13, 2024 (ML24318C462), the licensee provided a post-approval supplement letter to clarify analysis realized during implementation.
The licensee states that the reason for the proposed SEP changes is that the current TSC building has been selected as the centralized location for the new non-safety-related control platform installation due to its close proximity to the MCR and the existing Surry plant computer TSC ventilation system filter shine.
A detailed discussion of the licensees CLB LOCA source term and transport assumptions can be found in two Surry license amendment requests (ML003704270 and ML20338A542).
3.6.2.2 Infiltration of Airborne Radioactivity Using the CLB source term and transport assumptions for the dose consequence LOCA analysis, the licensee in its letter dated May 31, 2023, Table 4-1: Summary of TSC Dose Results, further identified and evaluated the TEDE contributions to TSC occupants from the following constituents:
Infiltration of airborne radioactivity into the TSC.
Direct dose from the accumulation of radioactive material on the TSC filter system.
Cloudshine - Dose from the external cloud of airborne radioactive materials surrounding the TSC.
Containment Direct Shine - Direct dose from the source term in containment.
Containment Skyshine - Dose from radiation scatter from atmosphere back to ground.
In the licensees letter dated November 18, 2022, Attachment 1, the licensee states that to limit the infiltration of airborne radioactivity, the TSC emergency ventilation system is designed to provide a filtered makeup air flow rate to maintain the TSC habitability envelope at a positive pressure (Attachment 1, page 13 of 36, as amended by ML24318C462). In its letter dated May 31, 2023, the licensee also states the filtration system air flow rates in Table 5-2,Summary of Changes for TSC Relocation LOCA Dose.
In its letter dated May 31, 2023, Attachment 1, Table 5-2, Summary of Changes for TSC Relocation LOCA Dose, the licensee states that the makeup flow rate is specified as a minimum of 670 cubic feet per minute (cfm) to a maximum of 1,100 cfm operational flow rate before isolation. The licensee also states that for the TSC mixing volume of 34,900 cubic feet, the after isolation, minimum pressurization makeup flow rate of 603 cfm will result in more than 0.5 volume changes per hour. In addition, the TSC ventilation system includes two-door vestibules to eliminate the intake of unfiltered in-leakage. The volume change stated above by the licensee, per SRP 6.4, allows for the least restrictive frequency for periodic verification.
Additionally, the licensees design uses a two-door vestibule to eliminate unfiltered in-leakage as is allowed by footnote 4 in SRP 6.4, footnote 4, (ML070550069) which states for a pressurized control room that infiltration is normally 5 L/s (10 cfm) infiltration [which] is assumed for conservatism. This flow could be reduced or eliminated if the applicant provides assurance that backflow (primarily as a result of ingress and egress) will not occur. This may mean installing two-door vestibules or equivalent. (NOTE: Unfiltered in-leakage is usually the summation of the contribution from opening and closing doors associated with activities in accordance with the plant emergency plans and procedures. Normally, 10 cfm is used for this unfiltered in-leakage.)
In its letter dated May 31, 2023, Attachment 1, the licensee states that the TSC ventilation filtered makeup pressurization system includes a filter bank consisting of a high-efficiency particulate air (HEPA) filter in series with a high-efficiency gas adsorption (HEGA) filter with a nominal, 1000 cfm, flow rate. This filter removes particulate radioactive air contaminants and remaining iodine compounds. RG 1.140 (ML16070A277) provides guidance regarding filter
ML24341A027 OFFICE DORL/LPL2-1/PM DORL/LPL2-1/LA DRA/ARCB/(A)BC NAME JKlos KZeleznock DGarmon for KHsueh DATE 12/19/2024 12/27/2024 and 01/10/2025 12/31/2024 OFFICE DORL/LPL2-1/BC DORL/LPL2-1/PM NAME MMarkley JKlos DATE 01/08/2025 01/13/2025