L-2024-137, Second Supplement to NextEra Energy Seabrook, LLC, Letter L-2024-108, Response to Request for Additional Information (RAI) Regarding One Time Extension to Technical Specification 3.8.1.1.a, Allowed Outage Time with One Independent .
| ML24225A265 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 08/12/2024 |
| From: | Rasmus P NextEra Energy Seabrook |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2024-137, L-2024-108 | |
| Download: ML24225A265 (1) | |
Text
August 12, 2024 L-2024-137 10 CFR 50.90 NextEra Energy Seabrook, LLC P.O. Box 300, Lafayette Road, Seabrook, NH 03874 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington DC 20555-0001 RE:
Seabrook Station Docket No. 50-443 Renewed Facility Operating License No. NPF-86 Second Supplement to NextEra Energy Seabrook, LLC, Letter L-2024-108, Response to Request for Additional Information (RAI) Regarding One Time Extension to Technical Specification 3.8.1.1.a, Allowed Outage Time with One Independent Circuit Between the Offsite Transmission Network and the Onsite Class 1E Distribution System Out-of-Service, March 4, 2024 (ADAMS Accession No. ML24198A026)
References:
- 1.
NextEra Energy Seabrook, LLC, Letter L-2024-061, License Amendment Request a One Time Extension to Technical Specification 3.8.1.1.a, Allowed Outage Time with One Independent Circuit Between the Offsite Transmission Network and the Onsite Class 1E Distribution System Out-of-Service, May 24, 2024 (ADAMS Accession No. ML24131A152)
- 2.
NRC Electronic Memorandum dated June 25, 2024, Request for Additional Information (RAI)
- Seabrook LAR offsite power, Regarding the One Time License Amendment Request to Revise Technical Specification 3.8.1, Offsite Sources - Operating, Seabrook Station, Unit 1, Docket No. 50-443
- 3.
NextEra Energy Seabrook, LLC, Letter L-2024-108, Response to Request for Additional Information (RAI) Regarding One Time Extension to Technical Specification 3.8.1.1.a, Allowed Outage Time with One Independent Circuit Between the Offsite Transmission Network and the Onsite Class 1E Distribution System Out-of-Service, March 4, 2024 (ADAMS Accession No. ML24198A026)
- 4.
NextEra Energy Seabrook, LLC, Letter L-2024-127, Supplement to NextEra Energy Seabrook, LLC, Letter L-2024-108, Response to Request for Additional Information (RAI)
Regarding One Time Extension to Technical Specification 3.8.1.1.a, Allowed Outage Time with One Independent Circuit Between the Offsite Transmission Network and the Onsite Class 1E Distribution System Out-of-Service, March 4, 2024 (ADAMS Accession No. ML24198A026, August 5, 2024 In Reference 1, NextEra Energy Seabrook, LLC (NextEra) requested, pursuant to 10 CFR 50.90, a one-time License Amendment to Renewed Facility Operating License NFP-86 for Seabrook Nuclear Plant Unit 1 (Seabrook). The proposed change to Technical Specification (TS) 3.8.1.1.a, A.C. Sources
- Operating, would provide a one-time allowance to change plant modes from Cold Shutdown (MODE
- 5) to Startup (MODE 2) while one independent circuit between the offsite transmission network and the onsite Class 1E Distribution System is out of service. NextEra is requested an additional 384 hours0.00444 days <br />0.107 hours <br />6.349206e-4 weeks <br />1.46112e-4 months <br /> to the 3.8.1.1.a 72-hour completion time for a total of 456 hours0.00528 days <br />0.127 hours <br />7.539683e-4 weeks <br />1.73508e-4 months <br />.
In Reference 2, the NRC staff forwarded Requests for Additional Information (RAIs) deemed necessary to complete its review. A clarification call was held with the staff, on June 25, 2024, and in
Seabrook Station L-2024-137 Docket Nos. 50-443 Page 2 of 3 Reference 3, NextEra provided a response to the RAIs. In Reference 4, NextEra requested a reduction in the one-time modified TS 3.8.1.1.a Allowed Outage Time (AOT) from 456 hours0.00528 days <br />0.127 hours <br />7.539683e-4 weeks <br />1.73508e-4 months <br /> to 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />.
In this second supplemental response, NextEra provides further clarification of the RAI responses in Reference 3. In addition, NextEra will apply defense-in-depth strategies and compensatory actions to reduce the risks associated with a 240-hour AOT extension. This submittal also corrects a compensatory action described in the RAI response of Reference 3 for severe weather. NextEra stated that, in advance of a 5-day prediction for severe weather, MODE changes from MODE 5 to MODE 4 would be prohibited. The correction is, in advance of a 2-day predication for severe weather, MODE changes from MODE 5 to MODE 4 would be prohibited.
to this submittal provides the second supplemental response to RAI questions, regarding the proposed amendment.
to this submittal provides a revised TS 3.8.1.1.a markup, indicating the requested AOT extension is 240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br />. The revised markup supersedes and replaces the corresponding TS 3.8.1.1.a markup page provided in Reference 1.
The information included in this Reference 1 supplement provides additional information that clarifies the application, does not expand the scope of the application as originally noted, and should not change the NRC staff¶s originally proposed no significant ha]ards consideration determination as published by the Federal Registered.
This letter contains no new or revised regulatory commitments.
Should you have any questions regarding this submission, please contact Mr. Kenneth Mack, Senior Manager, Licensing and Regulatory Compliance, at 561-904-3635.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on the 12th day of August 2024.
Sincerely, BBBBBBBBBBBBBBBBBBBBB Paul Rasmus General Manager, Regulatory Affairs Enclosures
- 1. Seabrook Second Supplemental Response to RAI 4uestions
- 2. Proposed Technical Specification Page Markup BBBBBBBBBBBBBBBBBBBBB For
Seabrook Station L-2024-137 Docket Nos. 50-443 Page 3 of 3 cc:
USNRC Region I Administrator USNRC Project Manager USNRC Senior Resident Inspector Director Homeland Security and Emergency Management New Hampshire Department of Safety Division of Homeland Security and Emergency Management Bureau of Emergency Management 33 Hazen Drive Concord, NH 03305 Kimberly A Castle, Technological Hazards Unit Supervisor The Commonwealth of Massachusetts Emergency Management Agency 400 Worcester Road Framingham, MA 01702-5399
Seabrook Station L-2024-137 Docket Nos. 50-443 Enclosure 1 Page 1 of 3
ENCLOSURE 1 SEABROOK SECOND SUPPLEMENTAL RESPONSE TO RAI QUESTIONS Response to EEEB RA-1 In response to EEEB RAI-1, the licensee states:
The expected minimum duration of the total allowed outage time is currently 5-7 days. The current Seabrook risk management procedure provides guidance that the unit should not enter the action statement unless the expected AOT is under 50% of the total available time. The current main generator testing schedule is still under development. To preclude additional AOT extension requests, 19 days was selected using risk informed input as the maximum expected total allowed outage time considering the 50% guidance and testing schedule uncertainty.
The staff notes that the above justification for the proposed AOT is not acceptable. During the clarification call for the RAI, the staff explained to the licensee that the proposed AOT cannot be justified by a risk analysis or risk input because this license amendment request is not a risk-informed application. The staff also notes that any uncertainty would be covered by the margin in the procedure.
Please provide a deterministic justification (for example, an estimated timeline with margin) for the proposed 456-hour AOT.
NextEra EEEB RAI-1 Supplemental Response:
The expected minimum duration of the total allowed outage is approximately 5 to 7 days.
Compensatory actions to be taken when entering the extended AOT will be promptly identified and implemented as appropriate for managing the risk associated with the maintenance of the main generator breaker. During the proposed AOT extension, human performance practices such as pre-job briefs, job site reviews, place-keeping, etc., which reduce the likelihood of human errors will continue to be implemented in accordance with plant administrative procedure and implementing procedures.
During the proposed AOT extension, defense-in-depth measures will be applied to maintain the safety function of the vital electrical buses. Risk significant configurations will not be entered, and risk reduction methods will be to maintain defense-in depth. Defense-in-depth measures meet the defense-in-depth philosophy because of redundant and diverse electrical equipment, the proposed AOT provides sufficient time with required margin to perform major maintenance action necessary for restoring inoperable UATs, defense-in-depth measures, including compensatory actions will help protect safety-related buses, EDGs and instrumentation necessary to safely shutdown the unit during a design basis event. Approximate dates and times are shown below. These dates and times are tentative as the outage schedule is subject to change as circumstances would have.
Approximate Maintenance Schedule without LAR Approval Milestones Approximate Date-Time (OPS) Open Main Generator Breaker, Beginning of OR23 Day = -23 (OPS) HANG DISPATCH TAGS - DE-ENERGIZE 345kv BUS 6 PER OS1046.04(Start of MGB replacement)
Day = -23
Seabrook Station L-2024-137 Docket Nos. 50-443 Enclosure 1 Page 2 of 3
(OPS) READY FOR MODE 4 - AWAITING MGB Day = -5 (PROJ) MGB READY FOR GENERATOR BREAKER CLOSURE WHEN PLANT CONDITIONS EXIST (GCB EC297176) (UATS RETURNED TO SERVICE)
Day 0, T= -
20hrs (OPS) ENTER MODE 4 Day 0, T=0hrs (OPS) ENTER MODE 3 Day 1, T= 3hrs Steam Driven Aux Feed Pump Test Complete Day 2, T=30hrs (OPS) ENTER MODE 2 Day 3, T=40hrs (OPS) Close Main Generator Breaker, End of OR23 Day 4, T=80hrs Approximate Maintenance Schedule with LAR Approval Milestones Approximate Date-Time (OPS) Open Main Generator Breaker, Beginning of OR23 Day = -23 (OPS) HANG DISPATCH TAGS - DE-ENERGIZE 345kv BUS 6 PER OS1046.04(Start of MGB replacement)
Day = -23 (OPS) Enter AOT Day = 0, T=0hrs (OPS) ENTER MODE 4 Day = 0, T=0hrs (OPS) ENTER MODE 3 Day = 0, T=13hrs Steam Driven Aux Feed Pump Test Complete Day = 2, T= 58hrs (OPS) ENTER MODE 2 perform Low Power Physics Testing Day = 3, T=81hrs (OPS) Return to MODE 3 Day = 3, T=89hrs (PROJ) MGB READY FOR GENERATOR BREAKER CLOSURE WHEN PLANT CONDITIONS EXIST (GCB EC297176)(UATS RETURNED TO SERVICE)
Day = 5, T=120hrs (OPS) ENTER MODE 2 Day = 5, T=121hrs (OPS) Close Main Generator Breaker, End of OR23 Day = 5, T=136hrs Response to EEEB RAI-2 In response to EEEB RAI-2, the licensee provided the following response about the BTP 8-8 recommended action to verify the operability of and preclude subsequent testing or maintenance activities on TS required systems, subsystems, trains, components, and devices that depend on the remaining power sources:
During the extended AOT, positive measures include compensatory actions that verify onsite AC sources, including the diesel generators and SEPS, are guarded and maintained available, and limiting switchyard and offsite transmission activity to only emergency work or as necessary to restore the UAT. Maintenance and testing activities will be controlled by existing Technical Specification requirements and approved procedures extended AOT.
Seabrook Station L-2024-137 Docket Nos. 50-443 Enclosure 1 Page 3 of 3
Please confirm that one train of TS required systems, subsystems, trains, components, and devices will be operable during the extended AOT to mitigate a design basis accident, if needed.
NextEra EEEB RAI-2 Supplemental Response:
TS required systems, subsystems, trains, components, and devices will be maintained and tested in accordance with TS Surveillance Requirements (SRs) to support MODE changes, during the AOT. TS equipment will be maintained OPERABLE, with the exception of the affected UATs, on either train during the extended AOT.
Response to EEEB RAI-3 In response to EEEB RAI-3, the licensee provided a list of compensatory actions that Seabrook will comply with during the proposed extended AOT.
- 1. In LAR section 3.0, the licensee provided the following action:
Operations will perform a Senior Reactor Operator (SRO) walkdown of all guarded equipment once per shift.
The above-mentioned action was not included in the list of compensatory measures in the response to EEEB RAI-3.
Please explain why the above-mentioned action is not included in the list of compensatory actions.
- 2. In LAR section 8.0, the licensee states:
Based on the risk insights, it is recommended that compensatory measures be taken to ensure that the area noted in Ref. 17 as a PRA Risk Area in the Turbine Building is protected during the time that the UATs are unavailable.
Clarify whether the above-mentioned PRA Risk Area in the Turbine Building is included in the list of compensatory actions. If not, why?
NextEra EEEB RAI-3 Supplemental Response:
Seabrook Turbine Building fire risk areas are identified in procedure FP 2.2, Control of Combustible Materials. Seabrook Operations will perform shiftly walkdowns, to ensure that no transient combustible materials are being stored in this area of the Turbine Building during the time that the UATs are unavailable.
Seabrook Station L-2024-137 Docket Nos. 50-443 ENCLOSURE 2 PROPOSED TECHNICAL SPECIFICATION PAGE (MARKUP)