ML23312A182
| ML23312A182 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 12/22/2023 |
| From: | Justin Poole Plant Licensing Branch 1 |
| To: | Coffey B NextEra Energy Seabrook |
| Poole J, NRR/DORL/LPLI, 415-2048 | |
| References | |
| EPID L-2022-LLA-0183 | |
| Download: ML23312A182 (1) | |
Text
December 22, 2023 Mr. Bob Coffey Executive Vice President, Nuclear and Chief Nuclear Officer Florida Power & Light Company NextEra Energy Seabrook, LLC Mail Stop: EX/JB 700 Universe Blvd.
Juno Beach, FL 33408
SUBJECT:
SEABROOK STATION, UNIT NO. 1 - ISSUANCE OF AMENDMENT NO. 172 RE: REVISION TO COOLING TOWER SERVICE WATER LOOP OR CELL REQUIREMENTS (EPID L-2022-LLA-0183)
Dear Mr. Coffey:
The U.S. Nuclear Regulatory Commission (the Commission) has issued the enclosed Amendment No. 172 to Renewed Facility Operating License No. NPF-86 for the Seabrook Station, Unit No. 1. This amendment consists of changes to the technical specifications (TSs) in response to your application dated December 9, 2022.
The amendment revises Technical Specifications (TS) 3/4. 7.4, Service Water System /
Ultimate Heat Sink, by increasing the allowed outage time for one inoperable cooling tower service water loop or one colling tower cell. Additionally, the amendment made an editorial correction to TS Section 1.9.
A copy of the related safety evaluation is enclosed. Notice of Issuance will be included in the Commissions monthly Federal Register notice.
Sincerely,
/RA/
Justin C. Poole, Project Manager Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-443
Enclosures:
- 1. Amendment No. 172 to NPF-86
DOCKET NO. 50-443 SEABROOK STATION, UNIT NO. 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 172 Renewed Facility Operating License No. NPF-86
- 1.
The Nuclear Regulatory Commission (the Commission) has found that:
A.
The application for amendment filed by NextEra Energy Seabrook, LLC, et al.
(the licensee), dated December 9, 2022, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commissions rules and regulations set forth in 10 CFR Chapter I; B.
The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C.
There is reasonable assurance (i) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commissions regulations; D.
The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E.
The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commissions regulations and all applicable requirements have been satisfied.
- NextEra Energy Seabrook, LLC, is authorized to act as agent for the: Hudson Light & Power Department, Massachusetts Municipal Wholesale Electric Company, and Taunton Municipal Lighting Plant (collectively, with NextEra Energy Seabrook, LLC, licensees) and has exclusive responsibility and control over the physical construction, operation and maintenance of the facility.
- 2.
Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 2.C.(2) of Renewed Facility Operating License No. NPF-86 is hereby amended to read as follows:
(2)
Technical Specifications The Technical Specifications contained in Appendix A, and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 172, are incorporated into the Renewed Facility Operating License No. NPF-86. NextEra Energy Seabrook, LLC shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
- 3.
This license amendment is effective as of its date of issuance and shall be implemented within 90 days of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION Hipólito J. González, Chief Plant Licensing Branch I Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Renewed Facility Operating License and Technical Specifications Date of Issuance: December 22, 2023 Michael L.
Marshall Digitally signed by Michael L. Marshall Date: 2023.12.22 11:10:58 -05'00'
ATTACHMENT TO LICENSE AMENDMENT NO. 172 SEABROOK STATION, UNIT NO. 1 RENEWED FACILITY OPERATING LICENSE NO. NPF-86 DOCKET NO. 50-443 Replace the following page of Renewed Facility Operating License No. NPF-86 with the attached revised page. The revised page is identified by amendment number and contains a marginal line indicating the area of change.
Remove Insert 3
3 Replace the following pages of the Appendix A, Technical Specifications, with the attached revised pages as indicated. The revised pages are identified by amendment number and contain marginal lines indicating the area of change.
Remove Insert 1-2 1-2 3/4 7-13 3/4 7-13 Amendment No. 172 (3)
NextEra Energy Seabrook, LLC, pursuant to the Act and 10 CFR Part 70, to receive, possess, and use at any time special nuclear material as reactor fuel, in accordance with the limitations for storage and amounts required for reactor operation, as described in the Final Safety Analysis Report, as supplemented and amended; (4)
NextEra Energy Seabrook, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to receive, possess, and use at any time any byproduct, source, and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required; (5)
NextEra Energy Seabrook, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to receive, possess, and use in amounts as required any byproduct, source, or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and (6)
NextEra Energy Seabrook, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility authorized herein.
(7)
DELETED C. This renewed license shall be deemed to contain and is subject to the conditions specified in the Commissions regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:
(1) Maximum Power Level NextEra Energy Seabrook, LLC, is authorized to operate the facility at reactor core power levels not in excess of 3648 megawatts thermal (100% of rated power).
(2) Technical Specifications The Technical Specifications contained in Appendix A, and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 172, are incorporated into the Renewed Facility Operating License No. NPF-86. NextEra Energy Seabrook, LLC shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.
DEFINITIONS CONTAINMENT INTEGRITY 1.7 CONTAINMENT INTEGRITY shall exist when:
a.
All penetrations required to be closed during accident conditions are either:
1)
Capable of being closed by an OPERABLE containment automatic isolation valve system, or 2)
Closed by manual valves, blind flanges, or deactivated automatic valves secured in their closed positions.
b.
All equipment hatches are closed and sealed, c.
Each air lock is in compliance with the requirements of Specification 3.6.1.3, d.
The containment leakage rates are in accordance with the Containment Leakage Rate Testing Program, and e.
The sealing mechanism associated with each penetration (e.g., welds, bellows, or 0-rings) is OPERABLE.
CONTROLLED LEAKAGE 1.8 CONTROLLED LEAKAGE shall be that seal water flow supplied to the reactor coolant pump seals.
CORE ALTERATION 1.9 CORE ALTERATION shall be the movement of any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel.
Suspension of CORE ALTERATIONs shall not preclude completion of movement of a component to a safe position.
CORE OPERATING LIMITS REPORT 1.10 The CORE OPERATING LIMITS REPORT (COLR) provides core operating limits for the current operating reload cycle. The cycle specific core operating limits shall be determined for each reload cycle in accordance with Specification 6.8.1.6. Plant operation within these operating limits is addressed in individual specifications.
DIGITAL CHANNEL OPERATIONAL TEST 1.11 A DIGITAL CHANNEL OPERATIONAL TEST shall consist of exercising the digital computer hardware using data base manipulation and/or injecting simulated process data to verify OPERABILITY of alarm and/or trip functions. The Digital Channel Operational Test definition is only applicable to the Radiation Monitoring Equipment. The DIGITAL CHANNEL OPERATIONAL TEST may be performed by means of any series of sequential, overlapping, or total channel steps, and each step must be performed within the Frequency in the Surveillance Frequency Control Program for the devices included in the step.
SEABROOK - UNIT 1 1-2 Amendment No. 49, 81, 164, 172
PLANT SYSTEMS 3/4.7.4 SERVICE WATER SYSTEM/ULTIMATE HEAT SINK LIMITING CONDITION FOR OPERATION 3.7.4 The Service Water System shall be OPERABLE with:
a.
An OPERABLE service water pumphouse and two service water loops with one OPERABLE service water pump in each loop, b.
An OPERABLE mechanical draft cooling tower and two cooling tower service water loops with one OPERABLE cooling tower service water pump in each loop, and c.
A portable cooling tower makeup system stored in its design operational readiness state.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
NOTES--------------------------------------------------
- 1. Enter applicable ACTIONS of LCO 3.8.1.1, AC Sources-Operating, for diesel generator made inoperable by service water.
- 2. Enter applicable ACTIONS of LCO 3.4.1.3, Reactor Coolant Loops and Coolant Circulation, for residual heat removal loops made inoperable by service water.
a.
With one service water loop inoperable, return the loop to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
b.
With one cooling tower service water loop or one cooling tower cell inoperable, return the affected loop or cell to OPERABLE status within 21 days, or be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
c.
With two cooling tower service water loops or the mechanical draft cooling tower inoperable, return at least one loop and the mechanical draft cooling tower to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
d.
With two loops (except as described in c) or the service water pumphouse inoperable, return at least one of the affected loops and the service water pumphouse to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or be in at least HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
SEABROOK - UNIT 1 3/4 7-13 Amendment No. 32, 116, 161, 172 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 172 TO FACILITY OPERATING LICENSE NO. NPF-86 NEXTERA ENERGY SEABROOK, LLC SEABROOK STATION, UNIT NO. 1 DOCKET NO. 50-443
1.0 INTRODUCTION
By letter dated December 9, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22343A259), NextEra Energy Seabrook, LLC (NextEra or the licensee) submitted a license amendment request (LAR) to change the Technical Specifications (TSs) for Seabrook Station, Unit No. 1 (Seabrook). Specifically, the LAR would revise Technical Specification (TS) 3/4.7.4, Service Water System/Ultimate Heat Sink, by increasing the Allowed Outage Time (AOT) for one inoperable colling tower service water loop or one cooling tower cell from 7 days to 21 days. Additionally, the proposed LAR would make an editorial correction to TS Section 1.9. The proposed LAR was submitted following the guidance in Regulatory Guide (RG) 1.177, Revision 2, An Approach for Plant-Specific, Risk-Informed Decision-making: Technical Specifications (ADAMS Accession No. ML20164A034).
2.0 REGULATORY EVALUATION
2.1
System Description
Section 9.2.1 of the Updated Final Safety Analysis Report (UFSAR) describes the service water system and supplemental information related to the cooling tower complex in its support role for the ultimate heat sink (UHS) was provided in the LAR by the licensee.
The UHS complex consists of the Atlantic Ocean and atmosphere. The Atlantic Ocean serves as the normal UHS for Seabrook. In the unlikely event that the normal supply of cooling water from the Atlantic Ocean is unavailable, the atmosphere serves as the UHS using a mechanical draft evaporative cooling tower.
The Atlantic Ocean portion of the UHS is designed to perform all safety functions during and following the most severe natural phenomena anticipated, e.g., the safe shutdown earthquake (SSE), tornado, hurricane, flood, or low water level resulting from storm surges. The exceptions are the tunnels and transition structure, which are not designed for the SSE. In the unlikely event that an earthquake of sufficient intensity occurs, which blocks over 95 percent of the flow area of the intake tunnel, the cooling tower would be used as the ultimate heat sink.
In the unlikely event that the main circulating water tunnel is unavailable, a mechanical draft evaporative cooling tower serves as the UHS. The cooling tower is designed to supply cooling water to the primary component cooling water and to the diesel heat exchangers while sustaining a loss of offsite power and any single active failure. The tower, tower pumps and all the associated components are designed for the SSE heat loads, which assures that cooling water will be available from the UHS complex during and following all natural phenomena.
The mechanical draft cooling tower provides an alternate source of cooling water that it is completely independent of the circulating water tunnels and the Atlantic Ocean. In the unlikely event that level is lost in the Service Water Pumphouse, the heat loads are transferred from the Atlantic Ocean to the cooling tower. The cooling tower can be used during normal operation subject to the level and temperature limitations listed in the TSs.
Transfer of heat loads to the cooling tower can be performed manually on a system or component level from the main control board. Automatic transfer will occur on a train basis upon actuation of the associated tower actuation logic. The tower actuation logic, associated with each train, senses service water pump discharge pressure. A low-pressure condition, indicative of a low-low service water pumphouse level, will initiate tower actuation for the associated service water train.
The cooling tower complex is that portion of the UHS that includes a three (two of which are functional) cell tower, a basin with five (three of which are functional) interconnected compartments, two (one of which is functional) pump rooms and the associated piping, valves, and equipment. The functional portion of the cooling tower consists of one independent cell with one fan and a center cell with two fans. The functional portion of the basin consists of a pump well and one catch basin for each of the two functional tower spray cells. The unit has an A and a B cooling tower complex flow train. The pumps with associated piping, valves, and equipment in the trains circulate cooling water from the pump well basin through the primary component cooling heat exchangers and the secondary component cooling heat exchangers during normal operations or through the diesel generator heat exchangers during loss of offsite power conditions or through both during test. The flow is returned to the basin through either the respective tower sprays or through the spray bypass header, which distributes the return flow to each of the two-tower cell catch basins. A heat exchanger bypass line is provided from each pump discharge to the return line permitting cooling tower spray or spray bypass header recirculation independent of normal ocean cooling operations.
Each train-associated tower pump, fan, and associated electrical equipment serving a single primary component cooling water heat exchanger has a common emergency electrical power supply and is separated from the other train's power supply. A loss of power to the electrical equipment supplying one flow train would affect only that flow train and would still allow sufficient capacity for cooling the unit under a LOCA condition.
2.2 Proposed Changes to the Technical Specification 2.2.1 AOT From 7 To 21 Days The TS allowed outage times (AOTs) provide a limited time to restore equipment to operable status. The AOT represents a balance between the risk associated with continued plant operation with less than the required system or component redundancy and the risk associated with initiating a plant transient while transitioning the unit to a lower power state. Shutdown of the plant involves many plant operator activities and plant evolutions. These activities and evolutions provide challenges to plant equipment, opportunities for operator errors and increase the possibility of a plant trip.
The requested change would revise TS 3.7.4 to extend from 7 days to 21 days the AOT to return the inoperable cooling tower service water loop or cell to Operable status. The changes are shown below in bold.
The existing Limiting Condition for Operation, 3.7.4 states:
3.7.4 The Service Water System shall be Operable.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
- b. With one cooling tower service water loop or one cooling tower cell inoperable, return the affected loop or cell to Operable status within 7 days, or be in at least Hot Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
The proposed change to LCO 3.7.4 states:
3.7.4 The Service Water System shall be Operable.
APPLICABILITY: MODES 1, 2, 3, and 4.
ACTION:
- b. With one cooling tower service water loop or one cooling tower cell inoperable, return the affected loop or cell to Operable status within 21 days, or be in at least Hot Standby within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.
The proposed license amendment is needed to provide sufficient time for cooling tower service water loop or cell troubleshooting and maintenance without initiating a plant shutdown or requesting Exercise of Enforcement Discretion and Emergency License Amendment to avert an orderly shutdown within 7 days.
2.2.2 Correction to TS Section 1.9 The changes are shown below in bold.
The existing TS 1.9 states:
CORE ALTERATION shall be the movement or any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONs shall not preclude completion of movement of a component to a safe position.
The proposed change to TS 1.9 states CORE ALTERATION shall be the movement of any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONs shall not preclude completion of movement of a component to a safe position.
2.3 Applicable Regulatory Requirements and Guidance The U.S. Nuclear Regulatory Commissions (NRCs) regulatory requirements related to the content of the TS are contained in 10 Code of Federal Regulation (10 CFR) Section 50.36. The regulations at 10 CFR 50.36 require that the TS include items in the following categories:
(1) safety limits, limiting safety systems settings, and limiting control settings; (2) limiting conditions for operation (LCOs); (3) Surveillance Requirements (SRs); (4) design features; and (5) administrative controls. SRs are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the LCOs will be met.
Specifically, the regulation at 10 CFR 50.36(c)(2)(i) Limiting conditions for operation states, in part, that LCOs are the lowest functional capability performance levels of equipment required for safe operation of the facility. When an LCO is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the TSs until the condition can be met. To issue or amend a license with a particular remedial action, the Commission must be able to find, among other things, that there is reasonable assurance that the activities authorized by the operating license (e.g., continued operation for a set amount of time when an LCO is not met) can be conducted without endangering the health and safety of the public.
The NRC staff reviewed the application in accordance with RG 1.177, Revision 2, which describes an acceptable approach for developing risk-informed applications for proposed TS changes to Completion Times. All risk-informed applications for changes to plant TS should explicitly address the five key principles described in RG 1.174 and RG 1.177. These key principles are the following:
Principal 1: The proposed licensing basis change meets the current regulations unless it is explicitly related to a requested exemption (i.e., a specific exemption under Title 10 of Code of Federal Regulation (CFR) 50.12).
Principal 2: The proposed licensing basis change is consistent with the defense-in-depth (DID) philosophy.
Principal 3: The proposed licensing basis change maintains sufficient safety margins.
Principal 4: When proposed licensing basis changes result in an increase in risk, the increases should be small and consistent with the intent of the Commissions policy statement on safety goals for the operations of nuclear power plants (Safety Goals for the Operations of Nuclear Power Plants; Policy Statement, 51 FR 30028 (Aug. 4, 1986)).
Principal 5: the impact of the proposed licensing basis change should be monitored using performance measurement strategies.
In addition to the key principles, RG 1.177 identifies a four element, three-tiered approach to evaluating proposed changes to a plants design, operations, and other activities that require NRC approval:
Element 1: Define the Proposed Change Element 2: Perform Engineering Analysis Element 3: Define Implementation and Monitoring Program Element 4: Submit Proposed Change Section 2.3.1, Acceptability of the Probabilistic Risk Assessment, of RG 1.177 states:
The [probabilistic risk assessment] PRA used to support the TS change evaluation is measured in terms of its appropriateness with respect to scope, level of detail, conformance to the technical elements, and plant representation. These aspects of the PRA are to be commensurate with its intended use and the role the PRA results play in justifying the TS change.
Section 2.3.2, Scope of the Probabilistic Risk Assessment for Technical Specification Change Evaluations, of RG 1.177 states:
At a minimum, evaluations of [core damage frequency] CDF and [large early release frequency] LERF should be performed to support any risk-informed changes to TS. The scope of the analysis should include all hazard groups (i.e., internal events, internal flood, internal fires, seismic events, high winds, transportation events, and other external hazards) unless the contribution from specific hazard groups does not affect the decision. When the risk associated with a particular hazard group or operating mode would affect the decision being made, the Commissions policy is to assess the risk using a staff-endorsed PRA standard for that hazard group or operating mode.
Sections C.2.3.1 and C.2.5 of RG 1.174 provide more detail.
3.0 TECHNICAL EVALUATION
3.1 AOT From 7 To 21 Days 3.1.1 Key Principle 1: Compliance with current regulations evaluation The licensee stated that this application is submitted pursuant to 10 CFR 50.90, and no exceptions or exemptions from applicable regulations or accepted industry codes and standards relevant to safe operation are proposed. The licensee has submitted a satisfactory no significant hazards consideration in accordance with 10 CFR 50.91 and 10 CFR 50.92. The licensee also fully described the proposed TS changes in the application. The NRC staff has reviewed the requirements of 10 CFR 50.36(c) and has concluded that the licensees amendment request is in compliance with 10 CFR 50.36(c). Therefore, the NRC staff concludes that the licensee continues to meet current regulations, and thereby the application met Principle 1 of the five key principles and Element 1 of the four element, 3-tiered approach described in RG 1.174 and RG 1.177.
3.1.2 Key Principle 2: Defense-in-depth evaluation In accordance with RG 1.177, Section 2.2. Deterministic Engineering Considerations, consistency with defense-in-depth philosophy is maintained as outlined in the seven points described below:
3.1.2.1 Reasonable balance The licensee stated that a reasonable balance among prevention of core damage, prevention of containment failure and consequence mitigation is preserved consistent with the defense-in-depth philosophy. A reasonable balance is preserved among prevention of core damage, prevention of containment failure, and consequence mitigation (i.e., the proposed change in a TS has not significantly changed the balance among these principles of prevention and mitigation) to the extent that such balance is needed to meet the acceptance criteria of the specific design-basics accidents and transients.
The amendment requested will result in no change to the current balance of these critical functions. The safety functions of the cooling tower complex are to provide an alternate source of cooling water in the unlikely event that the main circulating water tunnel is unavailable.
Seabrook has an A and a B cooling tower complex flow train, each with sufficient capacity for cooling the plant under a LOCA condition. Increasing the allowed outage time for one cooling tower service water loop or one cooling tower cell inoperable from 7 days to 21 days does not affect the ability of the cooling tower complex to meet the acceptance criteria of the specific design-basis accidents.
The balance between mitigation of core damage and containment failure is preserved by the implementation of this 21-day AOT for an inoperable cooling tower service water loop or cell in that the overall equipment reliability is expected to be improved, and over the long term, the licensee expects fewer emergent issues as a result of increased flexibility in planning and performing maintenance activities.
3.1.2.2 Programmatic activities The licensee stated that the over reliance on existing programmatic activities as compensatory measures associated with the change in the licensing basis is avoided. There are no changes to the design or operation of the ultimate heat sink associated with the proposed change. The cooling tower complex and its associated components that, when properly maintained, have proven to be reliable. An inoperable cooling tower service water loop or cell begins with entering the appropriate ACTION and evaluating the risk-significance of the repair consistent with 10 CFR 50.65(a)(4). Extending the AOT neither modifies the conditions warranting ACTION entry nor the risk-based considerations and station activities which assure safe operation.
3.1.2.3 System redundancy, independence, and diversity The licensee stated that system redundancy, independence, and diversity are preserved commensurate with the expected frequency and consequences of challenges to the system.
The redundancy, independence, and diversity of the service water system / UHS remain unchallenged as a result of the proposed licensing action.
During the proposed AOT extension, one of the two train-related cooling tower service water loops or cells will remain Operable and fully functional. As such, no disruption to the safety function of the service water system UHS will occur during the proposed AOT extension. All safety analysis assumptions and inputs remain valid. No additional compensatory actions would be taken upon the removal from service of one cooling tower service water loop or one cooling tower cell beyond those taken for the current allowed outage time. Because of the robustness of the design with regard to the accident analysis, such actions are not necessary. The defense-in-depth remains unchallenged by the proposed licensing action.
The risk impact of the proposed increase in the allowed outage time was explicitly modeled and determined to be small and consistent with regulatory guidance. The long-term effect of the proposed change on the reliability of the service water system / UHS is expected to be positive.
3.1.2.3.1 Maintenance practices Seabrooks response to concurrent equipment inoperability is unchanged by the proposed change, including cessation of the maintenance or plant shutdown if warranted. Should simultaneous equipment outages occur, the online risk management process will evaluate and implement appropriate risk-reduction measures.
Seabrook provides appropriate restrictions to preclude simultaneous equipment outages that would erode the principles of redundancy and diversity. Seabrook's online risk management process requires the risk of the planned maintenance repairs to be continuously evaluated based upon conditions, such as challenges to power grid stability, adverse weather conditions, and abnormal plant conditions. The proposed AOT extension does not alter the way these considerations are factored into the online risk assessment process.
The NRC staff finds the licensee has a sufficient on-line risk management process that ensures opposite trains of the cooling tower service water loops or cells will not be affected by planned maintenance activities during durations that the service water system proposed completion time of 21 days is imposed.
3.1.2.4 Defenses against potential common cause failure The licensee stated that defenses against potential common cause failures (CCF) are maintained and the potential for introduction of new CCF mechanisms is assessed. In the event of an inoperable cooling tower service water loop or cell, the redundant cooling tower service water loop or cell is sufficiently instrumented and monitored such that any CCF would be quickly identified, and appropriate action promptly taken. There are no changes to the design or operation of the service water system associated with the proposed change. Existing measures to ensure the potential for CCF is minimized include the process of evaluating operability, conducted by a licensed senior reactor operator, to assess the potential for common causes and effects on the other trains and components.
3.1.2.5 Independence of physical barriers The licensee stated that independence of physical barriers is not degraded. The physical barriers (fuel cladding, reactor coolant system (RCS), and containment) and their independence are maintained. The proposed change maintains the required cooling water capacity to the primary component cooling water and diesel heat exchangers and does not affect the integrity of the UHS as a barrier to limit leakage to the environment. Increasing the AOT for one cooling tower service water loop or one cooling tower cell removed from service does not affect the independence of the fuel cladding, RCS, or containment.
3.1.2.6 Defenses against human errors are maintained The licensee stated that defenses against human errors are preserved. Operators and maintenance personnel are in the practice of utilizing human performance practices such as pre-job briefs, job site reviews, place-keeping, etc., which reduce the likelihood of human errors.
This AOT extension is requested for Modes of operation 1 through 4, exactly as for the current TS 3.7.4; therefore, the methods and precautions required, which could affect human performance, are unaffected by the proposed license change.
3.1.2.7 Intent of plants design is maintained The licensee stated that the intent of the plant's design criteria is maintained. The operation of the cooling tower complex is not altered by the proposed extension to the AOT. The ability of the remaining TS required cooling tower service water loop or cell to mitigate the effects and consequences of an accident is not affected because no additional single failures are postulated while equipment is inoperable within the TS AOT.
3.1.2.8 NRC staff evaluation of defense-in-depth philosophy The NRC staff evaluated the seven defense-in-depth philosophies as described above by the licensee. The NRC finds that the proposed TS changes:
- 1. Do not degrade core damage prevention, and do not have any effect upon containment failure. Consequence mitigation remains unchallenged; credit is taken for only one cooling tower service water loop or cell for providing component cooling water in the plant safety analyses and no new accident or transients are introduced with the proposed changes; therefore, the likelihood of accidents or transients is not impacted.
- 2. The reliability of the UHS is not challenged by the proposed amendment; and no increase in programmatic activity is required to support the proposed change. Since the cooling tower complex is and will continue to be operated on a rotating basis, these reliability parameters will continue to be appropriate.
- 3. There are two redundant train-related cooling tower service water loops or cells, with each having the capability to provide the necessary component cooling under accident conditions.
- 4. The operating environment and operating parameters for the cooling tower complex are unaffected; and no new common cause failure modes are created by the proposed TS changes.
- 5. The physical barriers and their independence are maintained. The proposed change maintains the required cooling water capacity.
- 6. The proposed extension to the AOT does not require any new operator actions for the existing plant equipment or introduce the potential for new human errors.
- 7. The proposed change does not involve any physical changes to the design of the UHS or supporting systems.
Therefore, the NRC staff concludes that the defense-in-depth philosophy is maintained for the Service Water System/Ultimate Heat Sink, and so the licensee met Principle 2 of the five key principles of risk-informed regulation.
3.1.3 Key Principle 3: Safety margins evaluation The licensee stated that during the proposed AOT extension, the unaffected cooling tower service water loop or cell would remain fully operable and capable of performing its specified function. There is no change to the response time or acceptance criteria, and the AOT extension does not introduce new or altered methods of assessing plant performance. All safety analysis assumptions and inputs are unaffected and the margin to plant safety limits and limiting safety settings are unchanged. As such, the staff concludes there is no significant reduction in the safety margin due to the AOT extension, and the application met Principle of 3 of the five key principles of risk-informed regulation.
3.1.4 Key Principle 4: Risk is small and consistent with Commission policy evaluation The NRC staff evaluated the acceptability of the Seabrook PRA models and found that they have undergone several model updates to incorporate Improvements and maintain consistency with the as-built, as-operated plant. The staff noted that the Seabrook PRA models have also been through several self-assessments and were the subject of several recent internal events peer reviews in accordance with NRC-endorsed PRA Standard American Society of Mechanical Engineers/American Nuclear Society RA-Sa-2009 and RG 1.200 requirements. The staff also verified that the scope of the risk impact evaluation performed by the licensee appropriately included internal events, internal flood, fire, seismic, and addressed other hazards. Based on the above, the NRC staff finds the quality of the PRA models used to support the requested change in this application is acceptable.
RG 1.177 provides quantitative acceptance guidelines for risk impact related to AOT changes to be considered small and acceptable if the incremental conditional core damage probability (ICCDP) is less than 1.0E-6 and incremental conditional large early release probability (ICLERP) is less than 1.0E-7. The NRC staff reviewed the licensees evaluation methodology and the reported total increase in ICCDP of 5.93E-07 and ICLERP of 3.9E-12 due to the proposed change and determined that it is acceptable because the increase is well within the acceptance criteria of RG 1.177. This PRA analysis met Principle 4 of the five key principles and Element 2 of the four element, three-tiered approach prescribed in RG 1.177 3.1.5 Key Principle 5: Performance measurement strategies evaluation The licensee stated that during the proposed AOT extension, any repair activities on the inoperable cooling tower service water loop or cell would be evaluated for aggregate risk impacts to the station using NextEras Risk Management Program. In addition, work activity risk management (WARM) procedures are implemented to evaluate potentially risk-significant activities, which warrant the reduction of risks to acceptable levels. 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 repair consistent with 10 CFR 50.65(a)(4).
Therefore, the NRC staff concludes that the licensee has implemented adequate performance monitoring strategies to ensure the proposed AOT extension does not impact the performance criteria of the colling tower service water loop and cooling tower cell and has met Principle 5 of the five key principles and Element 3 of the four element, three-tiered approach prescribed in RG 1.177.
3.1.6 Technical Conclusion for AOT From 7 To 21 Days The NRC staff finds the seismic Category I mechanical draft cooling tower complex is not related to the prevention of core damage; however, the cooling tower complex provides an alternate source of cooling water which is completely independent of the circulating water tunnels and Atlantic Ocean and is designed to provide sufficient cooling capacity during a loss-of-coolant accident. As described in UFSAR Section 9.2.5, Ultimate Heat Sink, the cooling tower complex is designed to accommodate these accident heat loads while sustaining any single active failure. In addition, each train-associated tower pump, fan, and associated electrical equipment serving a single primary component cooling water heat exchanger has a common emergency electrical power supply and is separated from the other trains power supply. A loss of power to the electrical equipment supplying one flow train would affect only that flow train and would still allow sufficient capacity for cooling the unit under a LOCA condition.
With the proposed TS 3.7.4 Action b, AOT extension to 21 days, the remaining cooling tower service water loop or cell shall be operable. The safety function of the UHS is maintained and the increase in AOT addition of fourteen days as proposed by this amendment request has no effect in the prevention of containment failure and consequence mitigation and a reasonable balance among prevention of core damage, prevention of containment failure and consequence mitigation is preserved.
Based on the above, the NRC staff concludes that the licensees proposed changes to TS 3.7.4 meet current regulations, that the PRA quality supporting this application meet the requirements of RG 1.200, and the licensee has followed the five key principles of risk-informed regulation and the four element, 3-tiered approach in determining the risk impact as prescribed in RG 1.177. The staff also concludes that the proposed change is acceptable because the result of the analysis indicated that the increase in ICCDP and ICLERP is within the acceptance criteria of RG 1.177, the defense-in-depth philosophy and safety margin is maintained, and performance monitoring strategies have been implemented to ensure the proposed AOT extension does not impact the performance criteria of the colling tower service water loop and cooling tower cell.
3.2 Correction to TS Section 1.9 By letter dated April 3, 2002 (ML020510578 (letter), ML020950691 (TS pages)), the NRC issued Amendment No. 81 for changes to the definitions in TS Sections 1.9, Core Alteration, 1.14, Engineered Safety Features Response Time, and 1.29 Reactor Trip Response Time.
TS page 1-2 issued with Amendment No. 81 revised TS Section 1.9 to read, CORE ALTERATION shall be the movement of any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONs shall not preclude completion of movement of a component to a safe position.
By letter dated March 18, 2019 (ML19079A240), the licensee requested changes to Point Beach, Seabrook, and Turkey Point TS definitions to adopt TSTF-563, Revise Instrument Testing Definitions to Incorporate the Surveillance Frequency Control Program. The licensee requested changes to Seabrook TS page 1-1 to change Sections 1.3, Analog, Channel Operational Test and 1.5, Channel Calibration; TS page 1-2 to change Section 1.11, Digital Channel Operational Test; and TS page 1-7 to change Section 1.39, Trip Actuating Device Operational Test. The marked-up TS page 1-2 that proposed a change to TS Section 1.11 included TS Section 1.9 that wasn't marked-up, but read, CORE ALTERATION shall be the movement or any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONs shall not preclude completion of movement of a component to a safe position. The license amendment request inadvertently proposed a change to TS Section 1.9.
By letter dated February 10, 2020 (ML19357A195), the NRC issued Amendments to Point Beach, Seabrook, and Turkey Point Units that revised the TS to adopt TSTF-563. Included was Seabrook Amendment No. 164 that issued TS page 1-2 that revised TS Section 1.11, but also included the inadvertent change to TS Section 1.9 that read, CORE ALTERATION shall be the movement or any fuel, sources, or reactivity control components within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONs shall not preclude completion of movement of a component to a safe position.
The NRC staff agrees that the licensees submittal from March 19, 2019, introduced an unintended error to TS 1.9 by changing the of to an or in the first sentence. The staffs issuance of Amendment No. 164 did not catch this unmarked change and issued TS page 1-2 with the erroneous or. The NRC agrees that the appropriate wording of TS 1.9 for Seabrook should state CORE ALTERATION shall be the movement of any... and therefore approves the change.
4.0 STATE CONSULTATION
In accordance with the Commissions regulations, the New Hampshire and Massachusetts State officials were notified of the proposed issuance of the amendment on November 7, 2023. The State officials had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20. The NRC staff finds that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (February 21, 2023; 88 FR 10557). Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commissions 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.
Principal Contributors: T. Dinh, NRR B. Lee, NRR J. Poole, NRR Date of Issuance: December 22, 2023
- via memorandum OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DRA/APLB/BC*
NAME JPoole KZeleznock JWhitman DATE 11/15/2023 11/14/2023 09/21/2023 OFFICE NRR/DSS/SCPB/BC*
NRR/DSS/STSB/BC(A)
OGC - NLO NAME BWittick SMehta BVaisey DATE 10/23/2023 11/20/2023 12/15/2023 OFFICE NRR/DORL/LPL1/BC NRR/DORL/LPL1/PM NAME HGonzález (MMarshall for)
JPoole DATE 12/21/2023 12/22/2023