IR 05000443/2019010

Design Bases Assurance Inspection Report 05000443/2019010

ML19184A010
Person / Time
Site:	Seabrook
Issue date:	07/03/2019
From:	Mel Gray NRC Region 1
To:	Nazar M NextEra Energy Seabrook
References
IR 2019010
Download: ML19184A010 (21)

Text

uly 3, 2019

SUBJECT:

SEABROOK STATION UNIT 1 - DESIGN BASES ASSURANCE INSPECTION INSPECTION REPORT 05000443/2019010

Dear Mr. Nazar:

On June 5, 2019, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Seabrook Unit 1 and discussed the results of this inspection with Mr. Eric McCartney, Site Vice President and other members of your staff. The results of this inspection are documented in the enclosed report.

Three findings of very low safety significance (Green) are documented in this report, all of which involved violations of NRC requirements. We are treating these violations as non-cited violations (NCV) consistent with Section 2.3.2.a of the Enforcement Policy.

If you contest the violations or significance or severity of the violations documented in this inspection report, you should provide a response within 30 days of the date of this inspection report, with the basis for your denial, to the U.S. Nuclear Regulatory Commission, ATTN:

Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region I; the Director, Office of Enforcement; and the NRC Resident Inspector at Seabrook.

If you disagree with a cross-cutting aspect assignment in this report, you should provide a response within 30 days of the date of this inspection report, with the basis for your disagreement, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001; with copies to the Regional Administrator, Region I; and the NRC Resident Inspector at Seabrook. This letter, its enclosure, and your response (if any) will be made available for public inspection and copying at http://www.nrc.gov/reading-rm/adams.html and at the NRC Public Document Room in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 2.390, Public Inspections, Exemptions, Requests for Withholding.

Sincerely,

/RA/

Mel Gray, Chief Engineering Branch 1 Docket No.: 50-443 License No.: NPF-86

Enclosure:

Inspection Report 05000443/2019010

Inspection Report

Docket Number: 05000443 License Number: NPF-86 Report Number: 05000443/2019010 Enterprise Identifier: I-2019-010-0050 Licensee: NextEra Energy Seabrook, LLC Facility: Seabrook Station Unit 1 Location: Seabrook, NH 03874 Inspection Dates: April 14, 2019 to May 04, 2019 Inspectors: S. Pindale, Senior Reactor Inspector (Team Leader)

J. Ambrosini, Senior Emergency Preparedness Inspector F. Arner, Senior Reactor Analyst M. Orr, Reactor Inspector J. Schoppy, Senior Reactor Inspector C. Baron, NRC Mechanical Contractor J. Nicely, NRC Electrical Contractor Approved By: Mel Gray, Chief Engineering Branch 1 Division of Reactor Safety

SUMMARY The U.S. Nuclear Regulatory Commission (NRC) continued monitoring the licensees performance by conducting a design bases assurance inspection at Seabrook Unit 1 in accordance with the Reactor Oversight Process. The Reactor Oversight Process is the NRCs program for overseeing the safe operation of commercial nuclear power reactors. Refer to https://www.nrc.gov/reactors/operating/oversight.html for more information.

List of Findings and Violations Improperly Sized Thermal Overload Relays for Throttling Motor-Operated Valves Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.21M Systems NCV 05000443/2019010-01 Open The team identified a finding of very low safety significance (Green) involving a Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, in that NextEra did not adequately verify or check the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program for several motor-operated valves (MOV). Specifically, NextEra did not verify the thermal overload (TOL) protective devices on eight safety-related emergency feedwater flow control MOVs were properly sized to support their safety function of repetitive jogging/throttling during transients and postulated events.

Inadequate 4kV Breaker Testing Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.21M Systems NCV 05000443/2019010-02 Open The team identified a finding of very low safety significance (Green) involving a Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, in that NextEras test program did not assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service in accordance with written test procedures that incorporate the requirements and acceptance limits contained in applicable design documents. Specifically, NextEras six-year inspection, testing and preventive maintenance procedure for 4kV safety-related breakers did not perform as-found electrical testing for breaker functions prior to performing preventive maintenance activities. As such, breaker degradation while in service may not be identified during the subsequent testing, and could prevent the identification of deterioration toward an unacceptable condition.

Survivability of Equipment during a Postulated Design Basis Accident Coincident with Degraded Offsite Power System Voltage Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.21M Systems NCV 05000443/2019010-03 Open The team identified a finding of very low safety significance (Green) involving a Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, in that NextEra did not verify or check the adequacy of design for setting thermal overload (TOL) protective devices, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program. Specifically, NextEra did not ensure that TOL protective device settings for specific motor-operated valves (MOVs) would prevent safety-related loads from becoming damaged or unavailable during a postulated design basis event involving a loss-of-coolant accident coincident with a degraded voltage of the offsite power supply system.

Additional Tracking Items None.

INSPECTION SCOPES Inspections were conducted using the appropriate portions of the inspection procedures (IP) in effect at the beginning of the inspection unless otherwise noted. Currently approved IPs with their attached revision histories are located on the public website at http://www.nrc.gov/reading-rm/doc-collections/insp-manual/inspection-procedure/index.html. Samples were declared complete when the IP requirements most appropriate to the inspection activity were met consistent with Inspection Manual Chapter (IMC) 2515, Light-Water Reactor Inspection Program - Operations Phase. The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel to assess licensee performance and compliance with Commission rules and regulations, license conditions, site procedures, and standards.

REACTOR SAFETY 71111.21M - Design Bases Assurance Inspection (Teams)

The team evaluated the following components, permanent modifications, and operating experience during the weeks of April 15, 2019, and April 29, 2019.

For the components, the team reviewed the attributes listed in Inspection Procedure 71111.21M, Appendix A, Component Review Attributes, such as those listed below. Specifically, the team evaluated these attributes as per 71111.21M, Appendix B, Component Design Review Considerations and 71111.21M, Appendix C, Component Walkdown Considerations.

Design Review - Large Early Release Frequency (IP Section 02.02) (1 Sample)

Containment Recirculation Sump A Isolation Valve, 1-CBS-V8

• Normal, abnormal, and emergency operating procedures

• Consistency among design and licensing bases and other documents/procedures

• System health report, maintenance effectiveness and records, and corrective action history

• Design calculations

• Surveillance testing and recent test results

• Testing of control system interlocks

• Diagnostic testing methodology

• Adequacy of electrical power supply for motor and controls

• Thermal overload protection settings The team used Appendix B guidance for Valves, Instrumentation, Electric Loads, and As-Built System.

Design Review - Risk-Significant/Low Design Margin Components (IP Section 02.02)

(5 Samples)

(1) A Primary Component Cooling Water Pump, CC-P-11-A

• Material condition and installed configuration (e.g., visual inspection/walkdown)

• Normal, abnormal, and emergency operating procedures

• Consistency among design and licensing bases and other documents and procedures

• System health report, maintenance effectiveness and records, and corrective action history

• Control logic (pump trip)

• Equipment/environmental controls and qualification

• Design calculations

• Surveillance testing and recent test results The team used Appendix B guidance for Valves, Instrumentation, Electric Loads, and As-Built System.

(2) Service Water Train A Isolation of Secondary Loads, SWS-MOV-V4

• Material condition and installed configuration (e.g., visual inspection/walkdown)

• Normal, abnormal, and emergency operating procedures

• Consistency among design and licensing bases and other documents/procedures

• System health report, maintenance effectiveness and records, and corrective action history

• Design calculations

• Adequacy of electrical power supply for motor and controls

• Thermal overload protection settings

• Surveillance testing and recent test results The team used Appendix B guidance for Valves, Instrumentation, Electric Loads, and As-Built System.

(3) 4160Vac Bus E5 and associated Emergency Diesel Generator A (electrical)

• Material condition and installed configuration (e.g., visual inspection/walkdown)

• Normal, abnormal, and emergency operating procedures

• Component health report, maintenance effectiveness and records, and corrective action history

• Coordination and interface with the transmission system operator

• Design calculations (e.g., load flow, bus loading and voltage drop, environmental temperature effects, degraded and loss of voltage protection, protective relay and breaker settings and coordination, short circuit/breaker duty analysis, and diesel generator loading)

• Surveillance testing and recent test results The team used Appendix B guidance for Instrumentation, Circuit Breakers and Fuses, Cables, Electric Loads, Motor Control Centers (MCCs), and As-built system.

(4) Supplementary Emergency Power System (Diesel Generator) Train A

• Material condition and installed configuration (e.g., visual inspection/walkdown)

• Normal, abnormal, and emergency operating procedures

• Consistency among design and licensing bases and other documents and procedures

• System health report, maintenance effectiveness and records, and corrective action history

• Design calculations (e.g., emergency diesel generator loading, voltage drop analyses)

• Surveillance testing and recent test results

• Equipment protection from fire, flood, and water intrusion or spray

• Heat removal cooling water and ventilation

• Energy sources, fuel and air (e.g., engine start, operation, and control)

The team used Appendix B guidance for Valves, Pumps, Instrumentation, Electric Loads, and As-Built System.

(5) Turbine-Driven Emergency Feedwater Pump, FW-P-37A

• Material condition and installed configuration (e.g., visual inspection/walkdown)

• Normal, abnormal, and emergency operating procedures

• Consistency among design and licensing bases and other documents/procedures

• System health report, maintenance effectiveness and records, and corrective action history

• Design calculations

• Surveillance testing and recent test results

• Turbine overspeed protection

• Pump steam binding protection

• Exhaust stack tornado missile protection

• Station blackout environmental conditions The team used Appendix B guidance for Valves, Instrumentation, and As-Built System.

Modification Review - Permanent Modifications (IP Section 02.03) (5 Samples)

(1) EC 145024, Reconciliation of Methods Used for Determining RWST Minimum Submergence Levels to Preclude Vortexing, Revision 0 (2) EC 145372, EDG Lube Oil High Temperature Trip Setpoint Change, Revision 2 (3) EC 284280, Increase in RCS Loop Tavg to Average Tavg Deviation Alarm Setpoint, Revision 0 (4) EC 291333, RC-V-122/124 Allowable Closure Time Increase, Revision 0 (5) EC 287636, Diesel Air Handling Calculation MSVCS-FAG-09, Revision and Service Environment Chart Update, Revision 0 Review of Operating Experience Issues (IP Section 02.06) (2 Samples)

(1) NRC Information Notice 2005-30, Safe Shutdown Potentially Challenged by Unanalyzed Internal Flooding Events and Inadequate Design, dated November 7, 2005 (2) NRC Information Notice 2016-05, Operating Experience Regarding Complications from a Loss of Instrument Air, dated April 27, 2016

INSPECTION RESULTS Improperly Sized Thermal Overload Relays for Throttling Motor-Operated Valves Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.21M Systems NCV 05000443/2019010-01 Open The team identified a finding of very low safety significance (Green) involving a Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, in that NextEra did not adequately verify or check the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program for several motor-operated valves (MOV). Specifically, NextEra did not verify the thermal overload (TOL) protective devices on eight safety-related emergency feedwater flow control MOVs were properly sized to support their safety function of repetitive jogging/throttling during transients and postulated events.

Description: The team noted that the safety-related emergency feedwater flow control MOVs FW-FV-4214A/B through FW-FV-4244A/B (eight valves) have a design function for repetitive jogging/throttling during transients and postulated design basis events. In calculation 9763-3-ED-00-28-F-CALC_009, NextEra selected TOLs based on the MOVs having three normal strokes to provide capability to recover from a mis-positioned MOV and provide protection of the MOV thermal limit during locked rotor conditions. However, the calculation methodology did not consider the design function of jogging/throttling the MOVs in sizing the TOL protective devices. TOL sizing calculations only addressed the MOV thermal limit function and the capability to recover from a mis-positioned MOV. Further, the team noted that there was not operator guidance or documented limitations regarding the maximum number of times each MOV can be cycled. As a result, the safety function of the MOVs was not ensured as the installed TOL protective devices could potentially actuate and cause spurious or unexpected tripping of the affected MOVs during postulated events. The team concluded the calculation methodology did not consider the design function that jogging/throttling MOVs have specific thermal overload performance requirements; and that sizing the TOLs required a unique I2t evaluation methodology to ensure that the valves would be able to perform the required number of jogging operations without tripping the TOLs. The I2t methodology considers specific electrical current values (I) for specific times (t)

as an MOV responds to jogging/throttling demand signals.

NRC Regulatory Guide 1.106 Revision 1, to which NextEra is committed in UFSAR Sections 1.8, 8.1.5.3 and 8.3.1.1, states in Regulatory Position C.2, that the trip setpoint of the TOL protection devices should be established with all uncertainties resolved in favor of completing the safety-related action. NRC Generic Letter 89-10, Supplement 1, provides additional guidance in Question 15, which states that licensees should review design basis information for each MOV in the program to identify whether, when and how often an MOV must be opened or closed.

Because the TOL sizing calculations only addressed the MOV thermal limit function and the capability to recover from a mis-positioned MOV, the resulting TOL design could have resulted in a spurious or unexpected actuation of the TOL protective devices and potentially prevented the MOV from performing a safety function to function during transients and postulated events.

Corrective Actions: NextEra performed a detailed analysis using the I2t methodology, and determined an appropriate limit for which the affected emergency feedwater MOVs could be throttled without adversely affecting the valves. The team reviewed the results and verified that they bounded the expected number of times operators may cycle these valves, and current MOV operability was not adversely affected. NextEra also plans on developing operator guidance regarding limitations and actions associated with the maximum number of times the affected valves can be throttled.

Corrective Action Reference: AR 02312915 Performance Assessment:

Performance Deficiency: NextEras failure to properly verify or check the adequacy of design, such as by the performance of design reviews or by the use of alternate or simplified calculational methods, for several MOVs was a performance deficiency within their ability to foresee and correct, and which should have been prevented. Specifically, NextEra did not verify the TOL protective devices on eight safety-related emergency feedwater flow control MOVs were properly sized to support their safety function of repetitive jogging/throttling during transients and postulated events.

Screening: The team determined this finding was more than minor because it was associated with the Design Control attribute of the Mitigating Systems cornerstone and affected the cornerstone objective of ensuring the availability and reliability of systems that respond to initiating events to prevent undesirable consequences.

Significance: The team assessed the significance of the finding using IMC 0609.04, Initial Characterization of Findings, and IMC 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions. The team determined that this finding was a deficiency affecting the design or qualification of a mitigating structure, system or component, where the structure, system or component maintained its operability or functionality. Therefore, the team determined the finding to be of very low safety significance (Green).

Cross-Cutting Aspect: None Enforcement:

Violation: 10 CFR Part 50, Appendix B, Criterion III, Design Control, requires that design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program.

Contrary to the above, as of May 3, 2019, NextEras design control measures did not provide for verifying or checking the adequacy of design of the TOLs for eight safety-related emergency feedwater flow control MOVs that had a jogging/throttling design function. As a result, NextEra could not assure the affected MOVs could perform their design safety function.

Enforcement Action: This violation is being treated as a non-cited violation, consistent with Section 2.3.2.a of the Enforcement Policy.

Inadequate 4kV Breaker Testing Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.21M Systems NCV 05000443/2019010-02 Open The team identified a finding of very low safety significance (Green) involving a Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion XI, Test Control, in that NextEras test program did not assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service in accordance with written test procedures that incorporate the requirements and acceptance limits contained in applicable design documents. Specifically, NextEras six-year inspection, testing and preventive maintenance procedure for 4kV safety-related breakers did not perform as-found electrical testing for breaker functions prior to performing preventive maintenance activities. As such, breaker degradation while in service may not be identified during the subsequent testing, and could prevent the identification of deterioration toward an unacceptable condition.

Description: The team reviewed NextEras activities associated with preventive maintenance and testing of safety-related 4kV breakers. In particular, the team evaluated whether the breaker testing activities were capable of detecting breaker degradation.

As documented in UFSAR Section 8.1.5.2, NextEra is committed to IEEE 308-1971, Standard Criteria for Class IE Electric Systems for Nuclear Power Generating Stations, and IEEE Standard 338-1975, Standard Criteria for the Periodic Testing of Nuclear Power Generating Station Class 1E Power and Protection Systems. IEEE 308-1971 states that tests shall be performed at scheduled intervals to detect the deterioration of the system toward an unacceptable condition (Section 6.3, Periodic Equipment Tests); and IEEE Standard 338-1975, states that functional tests shall assure that the tested equipment is capable of performing its design function (Section 6.3.2, Functional Tests). The team noted that NextEra's 4kV power circuit breaker maintenance procedure LX0558.01 4.16kV Breaker Inspection, Testing and PM, which is performed on a six-year frequency, did not perform as-found electrical testing for breaker functions, such as breaker timing, and reduced voltage testing of the trip/close coils prior to inspecting, cleaning, and lubricating the breakers. NextEra implemented the mechanical and electrical portions of the procedure separately and sequentially. The team reviewed the procedure and noted the mechanical portion of the activity was preventive maintenance (inspecting, cleaning, lubricating) and was typically performed prior to the electrical/testing portion. The team determined that the nature and sequence of the activities pre-conditioned the breakers prior to performing the electrical/testing part of the procedure. Since there was no as-found testing performed prior to the preventive maintenance, the team concluded the sequence of the activities performed could mask breaker degradation and prevent the identification of deterioration toward an unacceptable condition as specified in IEEE 308-1971 and 338-1975.

In addition to the IEEE 308-1971 and 338-1975 standards, the team noted NRC Information Notice 97-16, Preconditioning of Plant SSCs before ASME Code In-service Testing or Technical Specification Surveillance addressed this issue. Specifically, the document discussed instances where a surveillance procedure contained instructions requiring technicians to inspect, clean, and lubricate several breakers before performing the as-found testing of several breaker functions; but since those functions could have been affected by

the cleaning and lubrication, the test results did not represent the as-found condition of the breakers.

Corrective Actions: NextEra plans to evaluate their 4kV breaker preventive maintenance and testing process to ensure as-found testing is appropriately performed. The team verified there were no instances where the affected 4kV breakers had significantly degraded toward unacceptable performance notwithstanding the lack of as-found testing.

Corrective Action Reference: AR 02312582 Performance Assessment:

Performance Deficiency: NextEras failure to assure that testing required to demonstrate that structures, systems, and components will perform satisfactorily in service in accordance with written test procedures that incorporate the requirements and acceptance limits contained in applicable design documents was a performance deficiency within their ability to foresee and correct, and which should have been prevented. Specifically, NextEra did not perform periodic equipment tests in a manner such that they would effectively detect the deterioration of the equipment toward an unacceptable condition.

Screening: The team determined this finding was more than minor because it was associated with the Equipment Performance attribute of the Mitigating Systems cornerstone and affected the cornerstone objective of ensuring the availability and reliability of systems that respond to initiating events to prevent undesirable consequences. The finding was also more than minor because if left uncorrected, it would have the potential to lead to a more significant safety concern.

Significance: The team assessed the significance of the finding using IMC 0609.04, Initial Characterization of Findings, and IMC 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions. The team determined that this finding was not a deficiency affecting the design or qualification of a mitigating structure, system or component, did not represent a loss of system and/or function, and did not represent an actual loss of function. Therefore, the team determined the finding to be of very low safety significance (Green).

Cross-Cutting Aspect: None Enforcement:

Violation: 10 CFR Part 50, Appendix B, Criterion XI, Test Control, requires that test program shall be established to assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service is identified and performed in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents.

Contrary to the above, as of May 3, 2019, NextEra did not assure that all testing required to demonstrate that structures, systems, and components will perform satisfactorily in service in accordance with written test procedures which incorporate the requirements and acceptance limits contained in applicable design documents. Specifically, NextEras six-year inspection, testing and preventive maintenance procedure for 4kV safety-related breakers did not perform as-found electrical testing for breaker functions prior to performing preventive maintenance activities. As such, breaker degradation while in service may not have been identified during the subsequent testing and could prevent the identification of deterioration toward an unacceptable condition as specified by industry standards.

Enforcement Action: This violation is being treated as an non-cited violation, consistent with Section 2.3.2.a of the Enforcement Policy.

Survivability of Equipment during a Postulated Design Basis Accident Coincident with Degraded Offsite Power System Voltage Cornerstone Significance Cross-Cutting Report Aspect Section Mitigating Green None 71111.21M Systems NCV 05000443/2019010-03 Open The team identified a finding of very low safety significance (Green) involving a Non-Cited Violation of 10 CFR Part 50, Appendix B, Criterion III, Design Control, in that NextEra did not verify or check the adequacy of design for setting thermal overload (TOL) protective devices, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program. Specifically, NextEra did not ensure that TOL protective device settings for specific motor-operated valves (MOVs) would prevent safety-related loads from becoming damaged or unavailable during a postulated design basis event involving a loss-of-coolant accident coincident with a degraded voltage of the offsite power supply system.

Description: The team evaluated the Seabrook design related to a postulated design basis event coincident with a degraded voltage of the offsite power supply system. In particular, the team evaluated whether safety-related equipment, which would automatically block load during such an event, was properly designed and maintained to ensure the equipment would function as expected. During the postulated scenario, it is assumed that voltage would remain degraded (less than the second level undervoltage setpoint but above the lower, loss of voltage setpoint) until the associated time delay of about 11 seconds would ultimately transfer the electrical power supply to the onsite power system automatically.

The team determined UFSAR Section 8.3.1.1.b.4.(b) stated if the second level undervoltage protection activation occurs coincidentally with an accident signal, the unit auxiliary transformer and reserve auxiliary transformer incoming line breakers are automatically tripped after a time delay to prevent spurious operation due to transients such as starting of large motors. That scenario would result in a total loss of voltage to the 4kV bus. That action, in turn, would result in connecting to and sequencing onto the associated emergency diesel generator.

NRC Branch Technical Position PSB-1, Adequacy of Station Electric Distribution System Voltages, dated July 1981, stated in part that the time delay associated with the second level of undervoltage protection should be of limited duration such that the permanently connected Class 1E loads will not be damaged.

NRC Regulatory Issue Summary (RIS) 2011-12, Revision 1, Adequacy of Station Electric Distribution System Voltages, was issued to clarify the NRC staffs technical position on existing requirements. RIS 2011-12 stated the time delay (at which the Class 1E buses should automatically separate from the offsite power supply) chosen should be optimized to ensure that permanently connected Class 1E loads are not damaged under sustained degraded voltage conditions, such as a sustained degraded voltage below the degraded voltage relay setting for the duration of the time delay setting.

NRC Regulatory Guide 1.106 Revision 1, to which NextEra is committed in UFSAR Sections 1.8 and 8.1.5.3, stated in Regulatory Position C.2, the trip setpoint of the TOL protection devices should be established with all uncertainties resolved in favor of completing the safety-related action.

The team determined NextEra did not ensure that safety-related MOV loads that would require starting during a postulated accident coincident with a degraded grid condition (second level undervoltage protection), had been verified to ensure the associated MOV protective devices (i.e., TOLs) would not trip so as to complete the associated safety-related action. The team observed in calculation 9763-3-ED-00-28-F-CALC_009, minimum trip times at a locked rotor condition were not evaluated to ensure the safety function would be met if an MOV stalled as the result of a degraded voltage condition. In particular, NextEra did not ensure that the TOL design for the associated 17 MOVs that would block load in that scenario were adequate to ensure the MOV safety functions would be accomplished for this scenario (i.e., the MOVs could have been subject to a transient degraded voltage, and possibly stall under certain conditions).

In response to the team's questions, NextEra staff demonstrated that the 4kV emergency buses were historically operated well above the degraded voltage relay setpoint, and have not seen a sustained undervoltage condition. In addition, the offsite power system was historically maintained above its rated 345kV voltage level. Operating procedure controls have been in place, and NextEra confirmed actual offsite power voltage levels have been functional and adequate to ensure the affected components and systems were not adversely impacted by this finding (five year operating history reviewed). In considering this issue, NextEra staff concluded that full qualification was not demonstrated. In accordance with their procedures, NextEra staff completed a prompt operability determination and developed interim actions pending final resolution of this issue. The team discussed the technical details and reviewed NextEras analyses and prompt operability determination, and found NextEras actions to be reasonable and appropriate.

Corrective Actions: NextEra staff performed detailed analyses and completed a prompt operability determination in response to this issue. Several compensatory interim actions were implemented to ensure that plant operators would take appropriate proactive actions based on specific conditions, including direction to declare both offsite power sources inoperable and entering the applicable technical specifications in the event Seabrook is notified of a post-contingent voltage condition of less than 345kV. Post-contingent voltage is the calculated voltage to which the grid would degrade in the event of a trip of Seabrook. Plant operators will also implement an additional action if the grid degrades further to immediately energize the two safety-related 4kV buses from the emergency diesel generators to ensure a degraded grid condition will not adversely affect the specific MOVs powered from safety buses. NextEra plans to implement additional, permanent corrective actions based on the results of their continuing evaluation of this issue.

Corrective Action Reference: AR 02312943 Performance Assessment:

Performance Deficiency: NextEras failure to properly verify or check the adequacy of design, such as by the performance of design reviews or by the use of alternate or simplified calculational methods, for 17 MOVs that are block loaded was a performance deficiency within their ability to foresee and correct, and which should have been prevented. Specifically, NextEra did not properly size TOL protective devices for 17 MOVs that would be required to

operate during a postulated design basis event coincident with a degraded voltage condition. As a result, NextEra did not demonstrate assurance that the MOVs would not become damaged or rendered unavailable during the postulated scenario.

Screening: The team determined this finding was more than minor because it was associated with the Design Control attribute of the Mitigating Systems cornerstone and affected the cornerstone objective of ensuring the availability, reliability and capability of systems that respond to initiating events to prevent undesirable consequences.

Significance: The team assessed the significance of the finding using IMC 0609.04, Initial Characterization of Findings, and IMC 0609, Appendix A, Exhibit 2, Mitigating Systems Screening Questions. The team determined that this finding was a deficiency affecting the design or qualification of a mitigating structure, system or component, where the structure, system or component maintained its operability or functionality. While this issue involved the qualification of several TOL protective devices during a particular degraded grid condition coincident with postulated design basis accident scenarios described in Chapter 15 (Accident Analyses) of the UFSAR, the affected MOVs were determined to be capable of performing their safety function, given the numerous equipment failures, conservative assumptions and specific system configurations that would have to occur to cause a deterministic system failure. Therefore, the team determined the finding to be of very low safety significance (Green).

Cross-Cutting Aspect: None Enforcement:

Violation: 10 CFR Part 50, Appendix B, Criterion III, Design Control, requires that design control measures shall provide for verifying or checking the adequacy of design, such as by the performance of design reviews, by the use of alternate or simplified calculational methods, or by the performance of a suitable testing program.

Contrary to the above, as of May 3, 2019, NextEras design control measures did not provide for verifying or checking the adequacy of design to ensure connected Class 1E loads would not be damaged or become unavailable for a postulated design basis event coincident with a degraded voltage condition.

Enforcement Action: This violation is being treated as an non-cited violation, consistent with Section 2.3.2.a of the Enforcement Policy.

EXIT MEETINGS AND DEBRIEFS The inspectors verified no proprietary information was retained or documented in this report.

• On May 3, 2019, the team presented the preliminary results of the Design Bases Assurance Inspection to Mr. Eric McCartney, Site Vice President, and other members of NextEra staff. After further in-office review, the final results of this inspection were presented to Mr. McCartney and the other NextEra staff via telephone on June 5, 2019.

Documents Reviewed Calculations 4.3.07-12F, PCCW Head Tank Overflow and Pump Suction Line Sizes and Pump NPSH Analysis, Revision 4 6.01.42.01, Control Building Elevation 21-6 and 50-0 4kV Switchgear Areas, Battery Rooms, MG Set Rooms and Cable Spreading Room Ventilation, Revision 7 9763-3-ED-00-01-F, Short Circuit Current Calculation, Revision 9 9763-3-ED-00-02-F, Voltage Regulation, Revision 14 9763-3-ED-00-23-F, Medium Voltage Protective Relay Coordination, Revision 6 9763-3-ED-00-28-F, Motor Control Center Protection, Revision 9 9763-3-ED-00-45-F, Control Building Heat Load Calculation, Revision 5 9763-3-ED-00-66-F, Control Circuit Voltage Drop, Revision 5 9763-3-ED-00-83-F, Diesel Generator Loading, Revision 17 C-S-1-20801, Emergency Feedwater System Flow Study, Revision 1 C-S-1-20805, EFW Pump Pressure at Overspeed Trip, Revision 1 C-S-1-20811, EFW System Maximum Operating Pressure, Revision 0 C-S-1-20815, Low Suction Pressure Setpoint for Securing EFW Pumps, Revision 0 C-S-1-20823, EFW Pump IST Performance Requirements, Revision 0 C-S-1-20824, Emergency Feedwater Pump Exhaust Stack - Tornado Missiles, Revision 0 C-S-1-28076, Accidental RCS Depressurization Analysis, Revision 0 C-S-1-28137, Emergency Feedwater System High Flow Isolation Setpoint Analysis, Revision 0 C-S-1-45071, EFW Piping Qualification for Overpressurization, Revision 2 C-S-1-80903, MOV Differential Pressure Calculations, Revision 1 C-S-1-80904, MOV Thrust, Actuator Capability and Torque Switch Setpoint Calculations, Revision 4 C-S-1-83704, Hydraulic Modeling of PCCW Flow Distribution, Revision 3 C-S-1-83805, CBS-V8/V14 Bonnet Pressure Calculation, Revision 0 C-S-1-83807, Determination of Delta-P, CBS-V8 and V14, Revision 0 C-S-1-83808, Post-LOCA Heatup of Valves CBS-V8 and V14, Revision 0 C-S-1-84213, Appendix R Timing Calculations for Reactor Coolant Inventory Control, Revision 2 C-X-1-21802, Expansion Joint Rupture in the Circulating Water System Located in the Turbine Building, Revision 3 FP98328, Required Thrust and Weak Link Calculations, Revision B FP98522, Actuator Sizing and Valve Weak Link Analysis, Revision 0 SBC-128, Technical Specifications, Setpoints and Allowable Values, Revision 17 Engineering Evaluations and Modifications 10CFR50.59 Screen 2004-286, Substitution of Enhanced Operator Action for Turbine Building Scuppers, Revision 0 10CFR50.59 Screen 2015-50, Fukushima SEPS Components Seismic Upgrades, Revision 0 10CFR50.59 Screen 2015-51, Fukushima SEPS Foundations, Enclosures, and Exhaust Seismic Upgrades, Revision 0 10CFR50.59 Screen 2016-229, Diesel Air Handling Calculation MSVCS-FAG-09 Revision and Service Environment Chart Update, Revision 0 DCR 03-002, Supplemental Emergency Power System, 10/17/05 DCR 96-0016, PCCW Heat Exchanger Replacement, Revision 1 DCR 97-0027, Condensate Storage Tank Valve Room Heater, Revision 3 EC 145024, Reconciliation of Methods used for Determining RWST Minimum Submergence Levels to Preclude Vortexing, Revision 0 EC 145372, EDG Lube Oil High Temperature Trip Setpoint Change, Revision 2

EC 277469, 1-SW-V-4 Running Current Change, Revision 0 EC 282825, Fukushima SEPS Components Seismic Upgrades, Revision 1 EC 283031, Equivalent Design Package for SEPS-DG-2-A Exhaust System Material, Revision 2 EC 284280, Increase in RCS Loop Tavg to Average Tavg Deviation Alarm Setpoint, Revision 0 EC 286883, Replace CC-P-11-A Motor with Rewound Motor, Revision 1 EC 287231, Equivalent Design Package for SEPS-DG-2-A Alternator Guard Cover Plate, Revision 0 EC 291333, RC-V-122/124 Allowable Closure Time Increase, Revision 0 EE-91-07, Engineering Evaluation 91-07, dated 11/21/91 EQF 600-20-02, Medium Voltage Rewound Large AC Motors Electrical EQ File, Revision 4 LN0196, Inrush Current for a 11NA1 Actuator, 5/2/19 SEC15023-N7747, EQ Supplemental Report for Seabrook 700 HP CCW Pump Motor, Revision 0 Corrective Action ARs 05-13283 01862758 02310616 02311727* 02312590*

05-11758 02081772 02310694 02311729* 02312617*

00108591 02132107 02310735* 02311731* 02312622*

00124852 02150398 02310800* 02311860* 02312672*

00157729 02153536 02310928 02311899 02312764 00219030 02169116 02310929 02312144 02312824 00222271 02169596 02310959* 02312150 02312826 00222952 02256422 02311034* 02312273* 02312876*

00391503 02269582 02311078* 02312286 02312915*

01695541 02270102 02311079* 02312365 02312943*

01761439 02277088 02311107* 02312367* 02312974*

01764360 02289002 02311247* 02312540 02312985 01789108 02291116 02311634 02312582*

• AR written as a result of this inspection Design and Licensing Bases DBD-CC-01, Design Basis Document, Primary Component Cooling Water System, Revision 7 DBD-SW-01, Design Basis Document, Service Water System, Revision 8 LRAP-M021, Closed Cycle Cooling Water System Aging Management Program Basis Document, Revision 2 SBN-903, Letter to NRC, Resolution of Power System Branch Confirmatory Items, 11/27/85 Drawings 10120177, EDG Voltage Dip Curve, 12/27/77 1-CC-B20205, Primary Component Cooling Loop A Detail, Revision 27 1-NHY-202069, Diesel Generator Building Plans Above Grade General Arrangement, Revision 16 1-NHY-250000, Data Sheets for Motor- and Air-Operated Valves and Dampers, Revision 86 1-NHY-300219, Service Environment Chart, Revision 29 1-NHY-310002, Electrical Distribution One-Line Diagram, Revision 45 1-NHY-310007, 4160V Switchgear Bus 1-E5 One-Line, Revision 21 1-NHY-310013, 480V Unit Substation Buses E-51 and E-52 One-Line, Revision 22 1-NHY-310024, 480V MCC 1-E512, Revision 31 1-NHY-310027, 480V MCC 1-E521, Revision 34

1-NHY-312070, 4160V Supplemental Emergency Power System One-Line, Revision 1 1-NHY-503270, PCCW Pumps Logic Diagram, Revision 9 1-NHY-506194, Pumps P-11C and P-11A Loop A Control Loop Diagram, Revision 14 FP 23694, Pressures and Temperatures, DG Systems, Revision 1 FP35364, SEPS Generator Enclosure 2A Drawings, Revision 10 PID-1-FW-B20688, Emergency Feedwater System Details, Revision 12 PID-1-SEPS-B20953, SEPS Diesel Generator Fuel System Detail, Revision 0 PID-1-SEPS-B20954, SEPS Diesel Generator Cooling Water System Detail, Revision 1 PID-1-SI-20448, Safety Injection System - Low Head Injection, Revision 15 Procedures D4702, EFW Pump A Suction Header Pressure Low, Revision 3 D6569, DG A Lube Oil Temp High, Revision 12 D6619, DG B Lube Oil Temp High, Revision 10 D7193, RWST Level LO-LO, Revision 5 E-0, Reactor Trip or Safety Injection, Revision 57 E-1, Loss of Reactor or Secondary Coolant, Revision 44 E-2, Faulted Steam Generator Isolation, Revision 27 E-3, Steam Generator Tube Rupture, Revision 45 ECA-0.0, Loss of all AC Power, Revision 54 EE-04-024, Operator Action Response Times Assumed in the UFSAR, Revision 4 ES 1850.003, Motor-Operated Valve Performance Monitoring, Revision 15 ES-0.2, Natural Circulation Cooldown, Revision 38 ES-1.2, Post LOCA Cooldown and Depressurization, Revision 40 ES-1.3, Transfer to Cold Leg Recirculation, Revision 30 F4232, PCCW Pumps A and C Running, Revision 2 F7494, PCCW Pump A Trip, Revision 5 FR-C.1, Response to Inadequate Core Cooling, Revision 28 FR-H.1, Response to Loss of Secondary Heat Sink, Revision 37 LS0563.58, Trip Check Procedure for EDG Switchgear Breakers, Revision 3 LX0558.01, 4.16kV Breaker Inspection, Testing and PM, Revision 16 ON 1242.01, Loss of Instrument Air, Revision 16 ON 1242.02, Loss of Containment Instrument Air, Revision 13 ON1061.01, Operation of SEPS, Revision 12 ON1061.07, SEPS Maintenance Run, Rev. 7 OS1006.04, Operation of the Containment Spray System, Revision 27 OS1012.03, Primary Component Cooling Water Loop A Operation, Revision 25 OS1026.01, Operation of DG 1A, Revision 30 OS1036.01, Aligning the Emergency Feedwater System for Automatic Initiation, Revision 25 OS1036.04, Emergency Feedwater Pump B Operation, Revision 4 OS1090.05, Component Configuration Control, Revision 74 OS1200.00, Response to Fire or Fire Alarm Actuation, Revision 25 OS1212.01, PCCW System Malfunction, Revision 14 OS1216.01, Degraded Ultimate Heat Sink, Revision 23 OS1246.02, Degraded Vital AC Power, Revision 21 OS1456.99, Cold Leg Recirculation Valve Interlock Surveillance, Revision 0 OX1401.03, RCS Vent Path Block Valve Quarterly, Cold Shutdown, and 18-Month Surveillance Test, Revision 14 OX1406.13, Containment Recirculation Sump Valve Cold Shutdown Test, Revision 13 OX1436.02, Turbine-Driven EFW Pump Quarterly and Monthly Valve Alignment, Revision 29

OX1436.13, Turbine-Driven EFW Pump Post Cold Shutdown or Post Maintenance Surveillance and Comprehensive Pump Test, Revision 42 OX1456.81, Operability Testing of IST Valves, Revision 36 OX1456.86, Operability Testing of IST Pumps, Revision 18 OX1461.04, SEPS Monthly Availability Surveillance, Revision 12 SM 7.20, Control of Time Critical Operator Actions and Time Sensitive Actions, Revision 12 SOO 19-002, Interim Guidance for Resetting RMO, Revision 0 Functional, Surveillance and Modification Acceptance Testing 01209321-03, 1-CC-P-11-A Motor Replacement PMT, performed 11/17/16 1-CC-P-11A Pump/Motor Inboard/Outboard Bearing Oil Sample Analysis Trending, 2015-2018 40312073, MOV Diagnostic Testing Summary Report, 1-CBS-V-8, performed 10/13/15 IS1616.420, CC-T-2171A PCCW LP-A Supply Header Temperature Control Calibration, performed 12/11/17 IS1616.430, CC-T-2197A PCCW LP-A Supply Header Temperature Control Calibration, performed 10/21/14 LS0558.04, 4.16kV Circuit Breaker Refurbishment, performed 10/8/13 LS0563.151, 1-CC-P-11-A Trip Checks, performed 11/16/16 LS0563.22, Testing of Agastat 120Vac (7000 Series) TDPU Timing Relays, performed 10/19/17 LS0564.34, 4160V Static Motor Testing (1-CC-P-11-A), performed 11/15/16 LS0564.38, 4160V Dynamic Motor Monitoring (1-CC-P-11-A), performed 11/17/16 LX0558.01, 4.16kV Breaker Inspection, Testing and PM (EDE-BKR-06), performed 6/21/17 OS1412.13, PCCW Train A Quarterly Operability, 18-Month Position Indication and Comprehensive Pump Testing, performed 7/19/18 and 1/23/19 OX1401.03, RCS Vent Path Block Valve Quarterly, Cold Shutdown, and 18-Month Surveillance Test, performed 6/19/18 OX1426.22, EDG 1A 24-Hour Load Test and Hot Restart Surveillance, performed 11/15/17 OX1426.23, EDG 1B 24-Hour Load Test and Hot Restart Surveillance, performed 1/31/18 OX1426.32, Diesel Generator 1B 36-Month Operability Surveillance, performed 4/25/17 OX1426.34, Diesel Generator 1A 36-Month Operability Surveillance, performed 10/24/18 OX1461.04, SEPS Monthly Availability Surveillance, performed 2/19/19, 3/18/19 and 4/23/19 V1435744, 1-SEPS-DG-2A Engine Sump Analysis, performed 11/6/17 Vendor Documents and Specifications 9763-006-238-5, Specification for Primary Component Cooling Water Pumps, Revision 6 FP 34938, Limitorque Vendor Manual, Revision 26 FP 53455, Primary Component Cooling Pump Vendor Technical Manual, Revision 14 FP35465-16 C808-2, Cummins Engine Company Troubleshooting and Repair Manual, Power Generation Control Systems, QSK78 Series Engines, Volume 1, 7/30/04 SPEC-E-008, FPL Motor Repair/Refurbishment/ Rewind Requirements Specification, Revision 11 Miscellaneous SBK 16-005, Seabrook Nuclear Oversight Report - Maintenance, 9/27/16 SBK 17-003, Seabrook Nuclear Assurance Report - Design Engineering, 6/7/17 SBK 18-003, Seabrook Nuclear Assurance Report - Maintenance, 8/10/18 System Health Report, Diesel Generator System, Q1-2019 System Health Report, Electrical Distribution, Q1-2019 System Health Report, Primary Component Cooling Water, Q4-2018 System Health Report, Supplemental Emergency Power System, Q4-2018

Maintenance Work Orders 01209321 40397424 40493095 40534102 40550718 01211490 40397426 40497320 40534290 40584858 40207426 40433610 40498960 40539735 40611075 40235293 40446081 40498985 40539776 40611076 40270599 40490341 40510286 40539778 40611077 40312331 40493088 40514497 40547372 40365253 40493090 40531858 40550706 18