L-2025-052, NextEra Energy Seabrook Station, License Amendment Request to Revise Emergency Action Levels Due to Change in Containment Fire Detection System
| ML25132A013 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 05/12/2025 |
| From: | Mack K NextEra Energy Seabrook |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-2025-052 | |
| Download: ML25132A013 (1) | |
Text
NEXTera*
EN~
U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington D C 20555-0001 RE:
Seabrook Station Docket No. 50-443 Renewed Facility Operating License No. NPF-86 L-2025-052 10 CFR 50.90 10 CFR 50.54(q)
May 12, 2025 License Amendment Request to Revise Emergency Action Levels Due to Change in Containment Fire Detection System Pursuant to 10 CFR Part 50.90, NextEra Energy Seabrook, LLC (NextEra) hereby requests an amendment to Renewed Facility Operating License No. NPF-86 for Seabrook Station Unit 1 (Seabrook). The proposed changes update Emergency Action Levels (EALs) for Initiating Condition (IC) HU4 in procedure ER 1.1, "Classification of Emergencies," for Seabrook. A new fire detection system is to be installed inside the Seabrook Containment Building. This new fire detection system design is different than the existing system and the resulting system design requires changes to EALs for IC HU4. These EAL changes have been evaluated under the provisions of 10 CFR 50.54(q) and have been determined to require prior NRG approval.
The enclosure to this letter provides NextEra's evaluation of the proposed changes that demonstrates IC HU4 will continue to meet the requirements of 10 CFR 50.47(b). Attachment 1 to the Enclosure provides the Seabrook EALs for IC HU4 page to show the proposed changes. Attachment 2 contains the associated Basis page for IC HU4 to show the proposed changes.
NextEra has determined that the proposed changes do not involve a significant hazards consideration pursuant to 10 CFR 50.92(c), and there are no significant environmental impacts associated with the changes. The Seabrook Onsite Review Group has reviewed the proposed license amendment.
In accordance with 10 CFR 50.91 (b)(1 ), a copy of the proposed license amendment is being forwarded to the designee for the State of New Hampshire.
NextEra requests that the proposed changes be processed as a normal license amendment request, with approval within one year and implementation within 60 days following installation of the new Containment Building fire detection system. This system is scheduled to be installed in the Spring 2026 refueling outage.
Approval of this request is needed to support startup following the Seabrook Spring 2026 refueling outage.
This letter contains no new regulatory commitments.
NextEra Energy Seabrook, LLC P.O. Box 300, Lafayette Road, Seabrook, NH 03874
Seabrook Station Docket No. 50-443 L-2025-052 Page 2 of 2 Should you have any questions regarding this submittal, please contact Ms. Maribel Valdez, Fleet Licensing Manager, at 561-904-5164.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on the rz:"" day of May 2025.
Sincerely, ~z:~
Kenneth A. Mack Director, Licensing and Regulatory Compliance
Enclosure:
Description and Assessment
Attachment:
- 1. Proposed Emergency Action Levels for IC HU4
- 2. Proposed Basis for IC HU4 cc:
USNRC Regional Administrator, Region I USNRC Project Manager, Seabrook Station USNRC Senior Resident Inspector, Seabrook Station 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 Castle, Technological Hazards Unit Supervisor The Commonwealth of Massachusetts Emergency Management Agency 400 Worcester Rd.
Framingham, MA 01702-5399
ENCLOSURE Evaluation of the Proposed Changes License Amendment Request to Revise Emergency Action Level Due to Change in Containment Fire Detection System 1.0
SUMMARY
DESCRIPTION............................................................................... 1 2.0 DETAILED DESCRIPTION................................................................................ 1 2.1 Current System Description and Operation............................................................ 1 2.2 New System Description and Operation................................................................ 1 2.3 Current Requirements /Proposed Changes............................................................ 2 2.4 Reason for Proposed Changes............................................................................ 3
3.0 TECHNICAL EVALUATION
................................................................................ 4
4.0 REGULATORY EVALUATION
............................................................................ 6 4.1 Applicable Regulatory Requirements/Criteria......................................................... 6 4.2 No Significant Hazards Consideration................................................................... 7 4.3 Conclusion...................................................................................................... 8
5.0 ENVIRONMENTAL CONSIDERATION
................................................................. 9
6.0 REFERENCES
................................................................................................ 9 - Proposed Emergency Action Levels for IC HU4 - Proposed Basis for IC HU4
Seabrook Station Docket No. 50-443 1.0
SUMMARY
DESCRIPTION L-2025-052 Enclosure Page 1 of 9 Pursuant to 10 CFR Part 50.90, NextEra Energy Seabrook, LLC (NextEra) hereby requests an amendment to Renewed Facility Operating License No. NPF-86 for Seabrook Station Unit 1 (Seabrook). The proposed change updates Emergency Action Levels (EALs) for Initiating Condition (IC) HU4 in procedure ER 1.1, "Classification of Emergencies". NextEra requests approval of changes to EALs for IC HU4 due to implementation of a new fire detection system inside of the Seabrook Containment Building. This new fire detection system design is different than the existing system and the resulting system design requires changes to EALs for IC HU4.
2.0 DETAILED DESCRIPTION 2.1 Current System Description and Operation Seabrook maintains a fire detection network which utilizes a combination of smoke detectors, thermal detectors, and rate-of-rise detectors as means of providing station operators with complete fire status information. The current fire detection system installed in the Containment Building is a conventional (non-addressable) zoned system consisting of nine fire detection zones and four notification zones.
The nine detection zones consist of 137 ionization smoke detectors spaced throughout the (-)26' and O' elevations, including inside the biological shield (bio-shield) wall boundary. In addition, seven manual fire alarm pull stations are installed and wired into specific detection zone circuits.
The nine fire detection zones have between 8 and 23 smoke detectors connected together in a zone.
The detection zones cover specific areas of the Containment Building with little or no overlap in some areas.
Upon actuation of a smoke detector in a single zone, the zone becomes locked in alarm. Actuation of additional smoke detectors in the same zone will not be annunciated separately. A separate alarm will only be received if a smoke detector in another zone is activated. Operators cannot determine the exact location of an actuated smoke detector without entering the Containment Building and locating the detector in alarm.
2.2 New System Description and Operation A new addressable fire detection system will be installed in the Containment Building.
The addressable fire detection system allows for identification of an individual detector in alarm or in a trouble condition. Each detector has a unique address and will display a custom location message on a display panel in the Control Room (1-FP-CP-557) and on another display panel in the RCA Tunnel (1-FP-CP-376). This gives operators the exact location of the alarm and a potential fire. This significantly reduces the time for operators to locate a fire in the Containment Building. Additionally, the addressable detectors provide maintenance information on the fire panels to inform operators of the status of the detectors. This allows maintenance to be performed as needed, which reduces the number of unwanted alarms. There will be 120 smoke detectors installed in the Containment Building, outside of the bio-shield wall.
Due to high radiation areas inside of the bio-shield wall, the currently installed smoke detectors (17) in this area will be replaced with linear heat detection cable. The linear heat detection cable will be installed above the O' elevation inside the bio-shield wall and mounted to the current (existing) smoke detector conduit. The linear heat detection system is installed in two circuits. This ensures that detection is provided in the same areas as the existing smoke detection system.
The design and installation of the new fire detection system will be evaluated in accordance with 10 CFR 50.59 and in accordance with the Seabrook Fire Protection Program.
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 2 of 9 (1) 2.3 Current Requirements /Proposed Changes The proposed changes are to EALs for IC HU4 and a Note that applies to a containment fire alarm.
Current The approved Notes and EALs for IC HU4 are shown below.
Notes:
The STED/SED should declare the Unusual Event promptly upon determining that the applicable time has been exceeded, or will likely be exceeded.
A containment fire alarm is considered valid upon receipt of multiple zones (more than 1) actuated on CP-376 panel.
- a.
A FIRE is NOT extinguished within 15-minutes of ANY of the following FIRE detection indications:
Report from the field (i.e., visual observation)
Receipt of multiple (more than 1) fire alarms or indications Field verification of a single fire alarm
- AND **
- b.
The FIRE is located within ANY Table H2 plant rooms or areas:
Table H2 Condensate Storaqe Tank Enclosure Fuel Storaqe Buildinq Containment Primary Auxiliary Building Control Buildinq Service Water Pump House Cooling Tower Steam and Feedwater Pipe Chases Diesel Generator Buildinq North Tank Farm Emergency Feedwater Pump House Startup Feedwater Pump Area RHR/CBS Equipment Vaults
- OR **
(2)
- a. Receipt of a single fire alarm (i.e., no other indications of a FIRE)
- AND **
- b. The FIRE is located within ANY of the Table H2 plant rooms or areas except Containment in MODES 1 and 2 (see Note above):
- AND **
- c. The existence of a fire is not verified within 30 minutes of alarm receipt.
- OR**
(3)
A FIRE within the plant PROTECTED AREA or Dry Fuel Storage Facility not extinguished within 60 minutes of the initial report, alarm or indication.
- OR **
(4)
A FIRE within the plant PROTECTED AREA or Dry Fuel Storage Facility that requires firefighting support by an offsite fire response agency to extinguish.
Seabrook Station Docket No. 50-443 Proposed The proposed wording for EALs for IC HU4 and the Notes are shown below.
Notes:
L-2025-052 Enclosure Page 3 of 9 The STED/SED should declare the Unusual Event promptly upon determining that the applicable time has been exceeded, or will likely be exceeded.
(1)
A FIRE within the plant PROTECTED AREA or Dry Fuel Storage Facility not extinguished within 60-minutes of the initial report, alarm or indication.
- OR **
(2)
A FIRE within the plant PROTECTED AREA or Dry Fuel Storage Facility that requires firefighting support by an offsite fire response agency to extinguish.
This proposed wording for EALs for IC HU4 is shown in Attachment 1. Changes to the EAL basis are also proposed consistent with the proposed wording for EALs for IC HU4. The proposed EAL basis is shown in Attachment 2.
2.4 Reason for Proposed Changes The replacement fire detection system will be functionally equivalent to the existing system. It uses individually addressable detectors versus the current non-addressable detectors arranged in zones.
The new system creates a new ability to recognize multiple detectors in alarm versus the existing inability to see multiple detector alarms within an individual zone. This new capability creates the possibility for classification of an event which would be different than that approved by the NRC for Seabrook's site-specific application (Reference 1 ).
The change in the fire detection system in the Containment Building represents a reduction in effectiveness of the approved Seabrook EALs because the resulting event declaration for all potential fire event scenarios would not remain the same. Multiple alarms within an existing zone would not currently result in a declaration of an Unusual Event, but the new fire detection configuration would allow multiple individual alarms to be recognized within the same area as an existing zone and declaration of an Unusual Event would occur. This could cause an Unusual Event to be declared when the current fire detection scheme would not.
The change in the Containment Building exception from Modes 1 and 2 only to all Modes increases the scope of the exception. This is different than the EAL approved by the NRC for Seabrook's site-specific application (Reference 1 ).
Additionally, the removal of a specific panel for determining which fire zones are in alarm allows for the use of a fire detector alarm panel located in the Control Room along with a remotely located fire alarm panel to determine which detector(s) is in alarm. This is different than the EAL approved by the NRC for Seabrook's site-specific application (Reference 1 ).
3.0 TECHNICAL EVALUATION
The change in the Containment Building fire detection system is evaluated against the existing fire detection system to determine the effect of the change on the accuracy and timeliness of an affected emergency classification. The affected emergency classification is for IC HU4 - Fire potentially degrading the level of safety of the plant.
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 4 of 9 RG 1.219, (Reference 2), section C.4.4 discusses proposed changes to EALs and states:
"d. When considering proposed changes associated with EALs, the licensee must consider the effect of the change on the accuracy of the classification and the timeliness of the classification.... Accurate classifications are also important to avoid under-classifications and over-classifications.
The currently approved classification scheme at Seabrook is based on a plant-specific implementation strategy as provided for in NEI 99-01 Revision 6 (Reference 3) as reviewed and approved by the NRC (Reference 1 ). The NRC issued for public comment draft Regulatory Guide (DG) DG-1423, "Emergency Response Planning and Preparedness for Nuclear Power Reactors," on March 10, 2025, in the Federal Register (Reference 4). This DG (Reference 5) is proposed Revision 7 of Regulatory Guide 1.101, "Emergency Response Planning and Preparedness for Nuclear Power Reactors." Proposed Revision 7 of Regulatory Guide 1.101 would endorse Revision 7 of NEI 99-01 Revision 7, "Development of Emergency Action Levels for Non-Passive Reactors," dated September 2024 (Reference 6).
For IC HU4, NEI 99-01 Revision 7 removed EALs (1) and (2) because the associated events represent conditions that pose a safety risk low enough as to not reasonably require an emergency declaration. Activation of a site emergency plan and partial ERO mobilization would not be necessary to respond to the event.
A site would have sufficient procedures and capabilities to respond to these events without declaring an emergency (e.g., use of procedures and equipment described in the site Fire Protection Program). This includes performance of firefighting and post-event damage assessments, and identification and implementation of corrective/compensatory measures. Depending on the circumstances of the event, some plant response actions may also be required by Technical Specifications. Should the event have a more than minor impact, the resulting indications and reports would be assessed, and an emergency declared under another IC.
NEI 99-01 Revision 7 retained EALs (3) and (4) and renumbered them as EAL (1) and EAL (2).
In response to operating experience, the basis for EAL (2) was revised to make the condition requiring declaration clearer - the intent of the EAL and basis was not changed.
Seabrook is requesting to adopt IC HU4 as contained in NEI 99-01 Revision 7 dated September 2024. Accessing containment within 60 minutes to verify the status of a single alarm is a challenge as there are personnel safety concerns with any rapid entry into containment including environmental conditions such as heat and radiation levels in various locations. Actuation of multiple detectors is the most reliable indication of a valid fire detector alarm because of the volume of air flow throughout the containment building. Due to the Containment Building having multiple openings between floors, as well as intermediate floors, it is reasonable to conclude that smoke would be able to migrate throughout containment. There is constant air movement in containment due to the operation of the containment air handling units. The operating cooling units are drawing air to the units past the smoke detectors. It can be reasonably expected that a fire that burns for 15 minutes would produce sufficient products of combustion to cause multiple fire detectors to alarm. Actuation of multiple detectors is therefore the most reliable indication of a valid alarm and accurately meets the criteria of EAL HU4 (1 ). Verification of a single containment fire alarm that is likely to be spurious does not warrant the potential risks associated with a rapid Containment Building entry.
The NRC SER Section 3.5.4 in Reference 1 states:
"In addition to personal safety concerns associated with a rapid containment entry while operating at power, the licensee's containment building contains 137 fire detectors distributed over 9 zones, which in comparison, is approximately four times greater than the average number of containment building fire detectors in other NextEra nuclear power plants sites."
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 5 of 9 Even though the number of fire detectors (137) is mentioned, this value was stated only as evidence of the extensive fire detection system provided in the Containment Building and was not intended as a limiting or minimum number necessary to provide the fire detection function. This modification does reduce the total number of smoke detectors inside the Containment Building from 137 non-addressable ionization detectors in 9 zones to 120 addressable photoelectric detectors and replaces the 17 smoke detectors inside the bio-shield wall with 2 linear heat detection circuits. The use of individually addressable smoke detectors versus the current non-addressable detectors grouped into zones actually increases the number of detectors which could provide the additional alarm indication necessary to accurately classify an event using this EAL. This enhances the ability of plant operators to recognize an actual fire in a timely and accurate manner compared to the current system design.
Detector Design The new addressable smoke detectors are a photoelectric type versus the current ionization type. Photoelectric detectors are less prone to false alarms than ionization type detectors because they require products of combustion to enter a photo chamber and re-direct a light beam. Small amounts of dust or humidity will not actuate an alarm because it would not be sufficient to re-direct the light beam but could provide a trouble condition on the fire alarm panel indicating that the detector is dirty and needs servicing. If a detector becomes excessively dirty, it can be disabled from the fire alarm panel until service is performed to prevent false alarms.
The existing detection system does not have the capability to monitor detector sensitivity or disable individual detectors.
Ionization-type smoke detectors have a small amount of radioactive material between two electrically charged plates, which ionizes the air and causes current to flow between the plates.
When smoke enters the chamber, it disrupts the flow of ions, thus reducing the flow of current and activating the alarm. Small amounts of dust or high humidity can cause a false alarm on an ionization detector. The proposed use of addressable photoelectric smoke detectors in the Containment Building will reduce the likelihood of a false alarm and provide greater accuracy that multiple detectors in alarm is a true fire condition.
Linear heat detection inside the bio-shield wall is not prone to false alarms unless mechanically damaged. Linear heat detection consists of two twisted conductors separated by heat sensitive insulation. The heat sensitive insulation is available in a wide range of temperature ratings. Heat from a fire that reaches the temperature rating of the cable will melt the insulation and allow the two conductors to touch, activating the fire alarm. An alarm from the linear heat detection is highly likely due to an actual fire.
Timeliness The use of linear heat detection circuits versus the current smoke detectors within the bio-shield wall could introduce a very slight (-20 second) delay in activation of an alarm for fire scenarios within the bio-shield wall. An analysis documents a comparison of two proposed fire detection configurations located within the Containment Building bio-shield wall to determine the time to detection for the different configurations. The analysis was conducted to determine if the linear heat detection system would provide an equivalent detection time to smoke detectors in supporting identification and mitigation of a fire occurring within the bio-shield area. The results of this comparison indicate that both systems' configurations would detect a postulated design basis fire in less than one minute for the assumed base case. While the smoke detectors would respond slightly sooner than the linear heat detection circuits, the difference was less than 30 seconds even using conservative assumptions. This is considered a negligible difference in time-to-alarm compared to the overall event progression timeline. Therefore, the proposed system configuration of 120 individually addressable smoke detectors (outside the bio-shield wall) and 2 linear heat detection circuits (inside the bio-shield
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 6 of 9 wall) would present a negligeable change in the overall classification timeliness for a Containment Building fire event.
Accuracy The current Containment Building fire detector system configuration of 9 zones containing 137 non-addressable smoke detectors means that plant operators do not have the ability to distinguish multiple detector alarms within the same zone. This existing system capability was recognized in the present EALs by the addition of a Note that "(a) containment fire alarm is considered valid upon receipt of multiple zones (more than 1) actuated on CP-376 panel" as applied to EAL HU4 (2) in plant Modes 1 and 2. The proposed use of 120 individually addressable smoke detectors ( outside the bio-shield wall) and 2 linear heat detection circuits (inside the bio-shield wall) would now introduce the ability for plant operators to recognize multiple alarms that would not have been previously detectable in the existing configuration. While this increases the potential for the fire detection system to generate multiple alarms for a given fire scenario, this also creates the potential for classification of an event that would not be classified by the current approved EALs since they require the second alarm to be from a different zone to meet the HU4 EAL threshold. However, as discussed above, the use of photoelectric smoke detectors in the Containment Building will reduce the potential for false alarms and will increase the accuracy of reporting.
Conclusion The proposed changes to EALs for IC HU4 remain consistent with the overall EAL scheme development guidance and address the plant-specific implementation strategies provided, and are, therefore, consistent with a standard EAL scheme, as required by 10 CFR 50.47(b)(4).
4.0 REGULA TORY EVALUATION 4.1 Applicable Regulatory Requirements/Criteria The regulations in 10 CFR 50.54(q) provide direction to licensees seeking to revise their emergency plan. The requirements related to nuclear power plant emergency plans are contained in the standards in 10 CFR 50.47, "Emergency Plans," and the requirements of 10 CFR 50 Appendix E, "Emergency Planning and Preparedness for Production and Utilization Facilities."
10 CFR 50 Appendix E 10 CFR 50, Appendix E,Section IV.B, "Assessment Actions," requires that emergency plans include EALs that are to be used as criteria for determining the need for notification and participation of local and state agencies, and for determining when and what type of protective measures should be considered to protect the health and safety of individuals both onsite and offsite. EALs are to be based on plant conditions and instrumentation, as well as onsite and offsite radiological monitoring.
Section IV.B provides that initial EALs shall be discussed and agreed on by the applicant and state and local authorities, be approved by the NRG, and reviewed annually thereafter with state and local authorities. Therefore, a revision to EALs will require N RC approval prior to implementation if the EAL revision proposed by the licensee decreases the effectiveness of the emergency plan.
10 CFR 50.47 The requirements related to nuclear power plant emergency plans are contained in the standards in 10 CFR 50.47, "Emergency Plans". Section 50.47(b) contains standards that onsite and offsite emergency response plans must meet for the NRC staff to make a positive finding that there is reasonable assurance that adequate protective measures can and will be taken in the event of a radiological emergency. One of these standards, 10 CFR 50.47(b)(4), requires that emergency plans include a standard emergency classification and action level scheme.
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 7 of 9 10 CFR 50.54(q)
The requirements of 10 CFR 50.54 (q)(4) prohibit changes to an emergency plan that reduce the effectiveness of the plan without prior NRC approval. Any emergency plan change must continue to meet the requirements of 10 CFR 50.47(b) and the requirements of 10 CFR 50 Appendix E.
Regulatory Guide 1.219 This Regulatory Guide (Reference 2) describes methods that the staff of the NRC considers acceptable for use by nuclear power reactor licensees to change their emergency preparedness plans.
The proposed changes require prior NRC approval because they would result in an EAL that is inconsistent with the meaning or intent of the approved EAL basis such that the classification of the event would be different than that approved by the NRC in a site-specific application.
4.2 No Significant Hazards Consideration The proposed changes update the Emergency Action Levels (EALs) for Initiating Condition (IC) HU4 in the Emergency Response Plan for Seabrook. NextEra requests approval of changes related to implementation of a new fire detection system inside of the Seabrook Containment Building. This new fire detection system design is different than the existing system and the resulting system updates require changes to EALs for IC HU4.
As required by 10 CFR 50.91 (a), NextEra has evaluated the proposed changes using the criteria in 10 CFR 50.92 and has determined that the proposed changes do not involve a significant hazards consideration.
(1)
Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No The proposed changes to the Seabrook EALs for IC HU4 are based on a physical replacement of the Containment Building fire detection system. The proposed EAL changes do not alter the assumptions of any accident analyses. The proposed changes do not adversely affect accident initiators or precursors, and do not alter design assumptions, plant configuration, or the manner in which the plant is operated and maintained. The proposed changes do not adversely affect the ability of structures, systems or components (SSCs) to perform their intended safety functions in mitigating the consequences of an accident previously evaluated. Hence no impact on the consequences of any previously evaluated accident will result from the proposed changes.
Therefore, facility operation in accordance with the proposed changes would not involve a significant increase in the probability or consequences of an accident previously evaluated.
(2)
Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No No new accident scenarios, failure mechanisms, or limiting single failures are introduced as a result of the proposed changes. The changes do not challenge the integrity or performance of any safety-related systems. The changes do not alter the design, physical configuration, or method of operation of any plant SSC. EALs are not accident initiators; so, no new causal mechanisms are introduced.
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 8 of 9 Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any previously evaluated.
(3)
Does the proposed amendment involve a significant reduction in a margin of safety?
Response: No Margin of safety is associated with the ability of the fission product barriers (i.e., fuel cladding, reactor coolant system pressure boundary, and containment structure) to limit the level of radiation dose to the public. The proposed changes do not impact operation of the plant and no accident analyses are affected by the proposed changes. The changes do not affect the Technical Specifications or the method of operating the plant. Additionally, the proposed changes will not relax any criteria used to establish safety limits and will not relax any safety system settings. The safety analysis acceptance criteria are not affected by these changes.
The proposed changes will not result in plant operation in a configuration outside the design basis. The proposed changes do not adversely affect systems that respond to safely shut down the plant and to maintain the plant in a safe shutdown condition.
Therefore, operation of the facility in accordance with the proposed changes will not involve a significant reduction in the margin of safety.
Based upon the above analysis, NextEra concludes that the proposed license amendment does not involve a significant hazards consideration, under the standards set forth in 10 CFR 50.92, "Issuance of Amendment," and accordingly, a finding of "no significant hazards consideration" is justified.
4.3 Conclusion In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
5.0 ENVIRONMENTAL CONSIDERATION
The proposed amendment is applicable to emergency planning requirements involving proposed changes to EALs for IC HU4 - Fire potentially degrading the level of safety of the plant, and does not reduce the capability to meet the emergency planning standards of 10 CFR 50.47(b) and the requirements of 10 CFR 50, Appendix E. The proposed amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.
6.0 REFERENCES
- 1. Letter from NRC to NextEra, Issuance of Amendment RE: Adoption of Emergency Action Level Scheme Pursuant to NEI 99-01, Revision 6, dated February 10, 2017 (ADAMS Accession No. ML16358A411)
- 2. Regulatory Guide 1.219, Revision 1, Guidance on Making Changes to Emergency Plans for Nuclear Power Reactors, dated July 2016 (ADAMS Accession No. ML16061A104)
Seabrook Station Docket No. 50-443 L-2025-052 Enclosure Page 9 of 9
- 3. NEI 99-01, Revision 6, Development of Emergency Action Levels for Non-Passive Reactors, dated November 2012 (ADAMS Accession No. ML12326A805)
- 4.
Federal Register Notice Vol. 90, No. 45 (2025-03761) - Draft Regulatory Guide for Emergency Response Planning and Preparedness for Nuclear Power Reactors, dated March 10, 2025
- 5. NRC Draft Regulatory Guide DG-1423, Proposed Revision 7 to Regulatory Guide 1.101, Emergency Response Planning and Preparedness for Nuclear Power Reactors (ADAMS Accession No. ML24019A202)
- 6. NEI 99-01, Revision 7, "Development of Emergency Action Levels for Non-Passive Reactors," dated September 2024 (ADAMS Accession No. ML24274A312)
ATTACHMENT 1 EALs for IC HU4 (1 page follows)
,HU4 IHU4 ECL: Notification of Unusual Event Initiating Condition: FIRE potentially degrading the level of safety of the plant.
Operating Mode Applicability: All Emergency Action Levels: (1 or 2)
Notes:
For EAL #1, STED/SED should declare the Unusual Event promptly upon determining that the applicable time has been exceeded, or will likely be exceeded.
(1)
A FIRE within the plant PROTECTED AREA or Dry Fuel Storage Facility not extinguished within 60-minutes of the initial repmi, alarm or indication.
- OR**
(2)
A FIRE within the plant PROTECTED AREA or D1y Fuel Storage Facility that requires firefighting suppmi by an offsite fire response agency to extinguish.
ATTACHMENT 2 IC HU4 Basis Information (1 page follows)
'HU4
!BAS~S INFORMATION I
IHU4
- coNTINUED Basis:
FIRE: Combustion characterized by heat and light. Sources of smoke such as slipping drive belts or overheated electrical equipment do not constitute FIRES. Observation of flame is preferred but is NOT required if large quantities of smoke and heat are observed.
PROTECTED AREA: The area under continuous access monitoring and control, and armed protection as described in the site Security Plan.
This IC addresses the magnitude and extent of FIRES that may be indicative of a potential degradation of the level of safety of the plant.
With regard to containment fire alarms, accessing containment within 60-minutes to verify the status of a single alaim is a challenge as there are personnel safety concerns with any rapid entry into containment including environmental conditions such as heat and radiation levels in various locations. Due to the Containment Building having multiple openings between floors, as well as intermediate floors, it is reasonable to conclude that smoke would be able to migrate throughout containment. There is constant air movement in containment due to the operation of the containment air handling units. The operating cooling units are drawing air to the units past the smoke detectors. It can be reasonably expected that a fire that bums for 15-minutes would produce sufficient products of combustion to cause 3 or more fire detectors to alarm. Actuation of 3 or more fire detectors is therefore more reliable than a single fire detector of a valid ala1m.
For valid alarms in containment (3 or more alarms within 15-minutes that do not reset), the presence of fire in containment must be disproven within 60-minutes from the initial alarm, or an Unusual Event declai*ation is wananted.
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