SBK-L-20117, Response to Request for Additional Information Regarding Technical Specification 3/4.8.1 for a One-Time Extension of Allowed Outage Time License Amendment Request

Response to Request for Additional Information Regarding Technical Specification 3/4.8.1 for a One-Time Extension of Allowed Outage Time License Amendment Request

ML20267A542
Person / Time
Site:	Seabrook
Issue date:	09/23/2020
From:	Mccartney E NextEra Energy Seabrook
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SBK-L-20117
Download: ML20267A542 (11)

Text

September 23, 2020 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Seabrook Station Docket No. 50-443 Renewed Facility Operating License No. NPF-86 Seabrook Station NEXTera ENERGY ~

SEABROOK 10 CFR 50.90 SBK-L-20117 Response to Request for Additional Information Regarding Technical Specification 3/4.8.1 For a One-Time Extension of Allowed Outage Time License Amendment Request

References:

1.

NextEra Energy Seabrook, LLC letter SBK-L-20068, "License Amendment Request 20-01. One-Time Change to the Seabrook Technical Specifications A.C. Sources -

Operating", July 13, 2020 (ML20196L772).

2.

NRC Request for Additional Information Regarding Technical Specification 3/4.8.1 For a One-Time Extension of Allowed Outage Time, September 14, 2020 (ML20258A150).

In Reference 1, NextEra Energy Seabrook, LLC (NextEra) submitted Lic~nse Amendment Request (LAR) 20-01, requesting an amendment to Renewed Facility Operating License No. NPF-86 to extend the Allowed Outage Time for one Emergency Diesel Generator Inoperable from 14 days to 30 days, on a one-time basis.

In Reference 2, the NRC requested additional information to complete the review of LAR 20-01.

The enclosure provides NextEra's response to the NRC's Request for Additional Information. Attachment 1 to the enclosure provides a mark-up of the existing Technical Specifications page to show the proposed change.

SBK-L-20117 Page 2 of 2 This response does not alter the conclusion in Reference 1 that the change does not involve a significant hazards consideration pursuant to 10 CFR 50.92, and there are no significant environmental impacts associated with this change.

No new or revised commitments are included in this letter.

If you have any questions regarding this correspondence, please contact Mr. Kenneth Browne, Safety Assurance and Learning Site Director, at (603) 773-7932.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on September 23, 2020.

Sincerely, NextEra Energy Seabrook, LLC

~:artn:~

Site Vice President - Seabrook Nuclear Power Plant Enclosure cc:

NRC Region I Administrator NRC Project Manager NRC Senior Resident Inspector Director Homeland Security and Emergency Management New Hampshire Department of Safety Division of Homeland Security and Emergency Management Bureau of Emergency Management 33 Hazen Drive Concord, NH 03305 Katharine Cederberg, Lead Nuclear Planner The Commonwealth of Massachusetts Emergency Management Agency 400 Worcester Road Framingham, MA 01702-5399

Enclosure to SBK-L-20117 Page 1 of 7 Enclosure to SBK-L-20117 Response to Request for Additional Information Regarding the One-Time Change to the Seabrook Technical Specifications A.C. Sources - Operating, License Amendment Request 20-01

Enclosure to SBK-L-20117 Page 2 of 7 By letter dated July 13, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession number ML20196L772), NextEra Energy Seabrook, LLC (NextEra), requested an amendment to Seabrook Station (Seabrook) Technical Specifications (TS). The proposed license amendment request (LAR) revises the Seabrook TS 3/4.8.1, "A.G. [Alternating Current] - Operating," to extend the Allowed Outage Time (AOT) for one Emergency Diesel Generator (EOG) inoperable from 14 days to 30 days on a one-time basis. The proposed change will allow Seabrook to perform planned maintenance on the B EOG while at-power.

The NRG staff has identified the need for additional information to complete their review of the LAR.

Responses to these requests for additional information (RAls) are provided below.

RAl#1 BTP 8-8 states:

The supplemental source must have the capacity to bring a unit to safe shutdown (cold shutdown) in case of a loss of offsite power (LOOP) concurrent with a single failure during plant operation (Mode 1 ).

The LAR and Seabrook Updated Final Safety Analysis Report (UFSAR) Section 8.3, "Onsite Power Systems," state that the SEPS can provide the required safety related loads in the event of a loss of offsite power (LOOP) coincident with the loss of one or both EDGs.

The NRG staff notes that although the SEPS can supply the safe shutdown during LOOP concurrent with the loss of one or both EDGs, the capability of the SEPS to bring the plant to a cold shutdown is not stated in the UFSAR or the LAR.

Clarify whether the SEPS has the capacity (including the required fuel oil) to bring the unit to cold shutdown in the event of a LOOP concurrent with a failure of EOG A, while EOG B is unavailable.

NextEra Energy Seabrook Response #1 The total connected load necessary for SEPS is 4371 kW. Each of the two SEPS Generators has a capacity of 2700 kW per unit, for a combined total of 5400 kW.

Therefore, the SEPS Generators have sufficient capacity to power the connected loads.

The total fuel consumption required by SEPS to reach 200 degrees Fahrenheit is 8675.8 gallons. Each SEPS generator has a fuel tank containing 6085 gallons for a total of 12170 gallons available storage. Procedural requirements include a minimum of 4775

Enclosure to SBK-L-20117 Page 3 of 7 gallons of fuel per engine, for a total on hand supply of 9550 gallons. Therefore, sufficient fuel is available to achieve 200 degrees Fahrenheit, even at the minimum allowable fuel level.

Based on the above information, SEPS has the capacity (including the required fuel oil) to bring the unit to cold shutdown in the event of a LOOP concurrent with a failure of EOG A, while EOG B is unavailable.

RAl#2 BTP 8-8 states:

For plants using AAC or supplemental power sources discussed above, the time to make the AAC or supplemental power source available, including accomplishing the cross-connection, should be approximately one hour to enable restoration of battery chargers and control reactor coolant system inventory.

Seabrook UFSAR Section 8.3.1.2.b.1, "Regulatory Guide 1.6 - Independence Between Redundant Standby Power Sources," states:

The Supplemental Emergency Power System (SEPS) uses a transfer switch that has the capability of connecting the non-safety related SEPS DGs to a safety related circuit breaker on either redundant load group.

The NRG staff notes that the time to make the SEPS available to power the safety buses is not discussed in the UFSAR or the LAR.

Provide the time it takes to make the SEPS available to supply power to the safety buses.

NextEra Energy Seabrook Response #2 During the one-time AOT extension for maintenance on the B Emergency Diesel Generator (EOG), the transfer switch for SEPS will be aligned to Bus E6. In this alignment, if the station had a loss of offsite power (LOOP), SEPS would automatically start because the B EOG would not be available to repower Bus E6. Both conditions required for automatically starting SEPS (Bus E6 de-energized and MCC-152 de-energized) would be met. However, SEPS does not automatically connect to either emergency bus. During a LOOP event, in this configuration with the B EOG out of service, the A EOG would automatically start and repower Bus E5.

In this case the operators would respond using plant procedures. Bus E5 would be expected to be energized from the A EOG. However, with the B EOG not available, operators will re-energize Bus E6 utilizing SEPS by closing the SEPS feeder breaker to

Enclosure to SBK-L-20117 Page 4 of 7 Bus E6 from the Main Control Board (MCB) to repower the emergency bus. The Emergency Power Sequencer would sequence loads onto Bus E6.

In this scenario, the approximate time for Bus E6 to be repowered by SEPS would be 5

- 15 minutes. This task is not assigned as a Time Critical Task or a Time Sensitive Task, and timing runs have not been performed for the purpose of establishing an expected response time.

If the A EOG did not repower Bus E5 as described in the above scenario, then operations would enter a loss of all AC. (alternating current) power scenario. In this condition, the operators attempt to restore power to at least one emergency bus. They would do this first by trying to restore the A EOG. If not successful, operators are directed to utilize SEPS. The SEPS feeder breaker on Bus E6 would then be closed from the MCB to repower Bus E6.

The timeline to align SEPS to an emergency bus would likely be similar (5 to 15 minutes) to the loss of offsite power with the A EOG operating properly as described within the first scenario above. The second scenario task is not assigned as a Time Critical Task or a Time Sensitive Task, and timing runs have not been performed for the purpose of establishing an expected response time.

RAl#3 BTP 8-8 states: The licensee must provide justification for the duration of the requested AOT (actual hours plus margin based on plant-specific past operating experience).

The LAR proposes a one-time EOG AOT extension from 14 to 30 days.

Provide details of the timeline of maintenance activities which provide justification for the requested 30-day AOT extension based on Seabrook past operating experience.

NextEra Energy Seabrook Response #3 The major scope of work driving the current schedule for the B EOG outage includes the following extensive amount of maintenance activities:

Replacement of liner a-rings on 8 of the 16 cylinders (requires physical removal of pistons, connecting rods, liners and water jackets).

Retubing of the EOG jacket water heat exchanger, including cleaning and eddy current testing of tubes.

Replacement of EOG jacket water temperature control valve.

24 month EOG detailed inspection (e.g. block to base and foundation bolt tightness check, crankshaft web deflections and bearing clearance

Enclosure to SBK-L-20117 Page 5 of 7 measurements, crankcase inspection, camshaft and gear train inspection, air start check valve removal and inlet and exhaust valve spring inspection, inspecting cylinder liners with borescope, fuel rack roll pin inspection, overspeed trip mechanism static test, etc.).

Fuel rack rebuild.

The planned scope of work also includes extensive of draining lube oil, fuel oil and coolant water systems. The post maintenance testing requirements for the planned scope of work requires multiple runs of the engine to ensure satisfactory completion of the maintenance activities and to verify operability.

Relative to previous similar maintenance, a comparable scope of work was performed on the Seabrook A EOG during refueling outage OR19 (Fall 2018). This work required approximately 14 days to implement and retest.

The current schedule for the B EOG maintenance during the one-time AOT extension is approximately 18 days with contingencies. This time does not include any potential unanticipated discovery issues found during the maintenance interval which could extend the required outage period.

Additional AOT margin provides an allowance for unforeseen discovery issues that require immediate corrective maintenance which subsequently negatively impacts schedule duration. The additional margin also provides assurance that the unforeseen impacts to the overall maintenance schedule will not result in an unnecessary down-power, or the shutdown of the reactor without a corresponding health and safety benefit.

An additional challenge that is also being factored into the justification and necessity for a one-time 30 day AOT on the B EOG is the potential for unforeseen circumstances and uncertainty due to the public health emergency surrounding COVI0-19.

RAl#4 BTP 8-8 states:

The TS must contain Required Actions and Completion Times to verify that the supplemental AC source is available before entering extended AOT. The availability of AAC or supplemental power source shall be checked every 8-12 hours (once per shift). If the AAC or supplemental power source becomes unavailable any time during extended AOT, the unit shall enter the LCO and start shutting down within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. This 24-hour period will be allowed only once within any given extended EOG AOT.

The LAR does not discuss the TS requirements for the availability and unavailability of SEPS during the requested extended AOT from 14 to 30 days.

Enclosure to SBK-L-20117 Page 6 of 7 Provide the TS required actions and completion times to verify the availability of the SEPS before entering the 30-day AOT, to check the availability of the SEPS once per shift during the extended 30-day AOT, and to shut down the unit within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> if the SEPS becomes unavailable during the extended 30-day AOT.

NextEra Energy Seabrook Response #4 NextEra Energy proposes to revise ACTION b of TS LCO 3.8.1.1, by adding a new asterisk (*) to ACTION b(2)(a) and a new footnote denoted by the asterisk (*) as follows:

ACTION (a)

The requirement for restoration of the diesel generator to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> may be extended to 14 days* if the Supplemental Emergency Power System (SEPS) is available, as specified in the Bases, and

• A one-time AOT extension for an inoperable diesel generator allows 30 days to restore the associated diesel generator to OPERABLE status. Compensatory measures within NEE Letters SBK-L-20068 dated July 13, 2020, and SBK-L-20117 dated September 23, 2020, will remain in effect during the extended AOT period. The one-time AOT extension shall expire upon completion of the maintenance or 90 days after the issuance of the amendment, whichever comes first. In addition, SEPS availability will be checked prior to entering the 30-day extended AOT, and subsequently once per shift thereafter during the 30-day extended AOT. If SEPS becomes unavailable any time during the extended AOT, restore SEPS to available 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 the next 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 />. This 24-hour period will be allowed only once within any given extended EOG AOT.

The revised proposed Technical Specification page markup is provided in Attachment 1 of this Enclosure.

RAl#5 BTP 8-8 states:

The system load dispatcher will be contacted once per day to ensure no significant grid perturbations (high grid loading unable to withstand a single contingency of line or generation outage) are expected during the extended AOT.

TS required systems, subsystems, trains, components, and devices that depend on the remaining power sources will be verified to be operable and positive

Enclosure to SBK-L-20117 Page 7 of 7 measures will be provided to preclude subsequent testing or maintenance activities on these systems, subsystems, trains, components, and devices.

The LAR Section 3.2.1, "Compensatory Actions," provides compensatory measures including the below measure during the proposed AOT extension.

Operations will coordinate with grid operators and request that conditions remain stable in accordance with Master/Local Control Center Procedure No. 1 (M/LCC

1) - Nuclear Plant Transmission Operations. The extended AOT interval will not be entered if Seabrook has been notified of entry into Master/Local Control Center Procedure No. 2 (M/LCC 2) -Abnormal Conditions Alert.

The NRG staff notes that the above proposed compensatory measure appears to be applicable before entering the extended AOT only.

The NRG staff requests the following:

Confirm that the above compensatory measure for coordination with grid operators will be performed once a day during the extended AOT to ensure that significant grid perturbations (high grid loading unable to withstand a single contingency of line or generation outage) will not be expected during the extended AOT. Otherwise, provide a justification for the selected frequency of coordination with grid operations during the extended AOT.

NextEra Energy Seabrook Response #5 Master/Local Control Center [LCC] Procedure No. 1 (M/LCC 1) section 3.1 D contains real-time communication requirements that should occur as soon as possible, and always within 60 minutes, anytime voltage requirements cannot be met or the ability to provide an offsite power source is jeopardized, or the Independent System Operator (ISO) and LCC have lost the ability to assess the electric power system. In addition, M/LCC 1, attachment E, describes the requirements of weekly nuclear plant interface meetings that occur between ISO New England, Eversource Local Control Center, and the nuclear plant to review scheduled transmission work over the next two-week period.

As a compensatory measure during the extended one-time AOT for the B EOG, Seabrook operations will communicate daily with ISO New England, and "ensure that significant grid perturbations (high grid loading unable to withstand a single contingency of line or generation outage) will not be expected during the extended AOT."

Attachment to SBK-L-20117 ATTACHMENT 1 PROPOSED TECHNICAL SPECIFICATION PAGE (MARKUP)

(1 page follows)

ELECTRICAL POWER SYSTEMS A.C. SOURCES OPERATING LIMITING CONDITION FOR OPERATION 3.8.1.1 (Continued)

ACTION:

b.

With a diesel generator inoperable:

1)

Demonstrate the OPERABILITY of the remaining A.C. sources by performing Specification 4.8.1.1.1 a within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. Perform ACTION d. Demonstrate the OPERABILITY of the remaining diesel generator by performing Specification 4.8.1.1.2a.5) within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.*

2)

Restore at least two diesel generators 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 the next 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 />, unless the following condition exists:

(a)

The requirement for restoration of the diesel generator to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> may be extended to 14

• days if the Supplemental Emergency Power System (SEPS) is available, as specified in the Bases, and (b)

If at any time the SEPS availability cannot be met, either restore the SEPS to available status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> (not to exceed 14 days from the time the diesel generator originally became inoperable), or be in at least HOT STANDBY within the next 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 />.

• A one-time AOT extension for an inoperable diesel generator allows 30 days to restore the associated diesel generator to OPERABLE status. Compensatory measures within NEE Letters SBK-L-20068 dated July 13, 2020, and SBK-L-20117 dated September 23, 2020, will remain in effect during the extended AOT period. The one-time AOT extension shall expire upon completion of the maintenance or 90 days after the issuance of the amendment, whichever comes first. In addition, SEPS availability will be checked prior to entering the 30-day extended AOT, and subsequently once per shift during the 30-day extended AOT. If SEPS becomes unavailable any time during the extended AOT, restore SEPS to available 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 the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDO\\'V'N within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. This 24-hour period will be allowed only once within any given extended EDG AOT.

remaining diesel generator, or

3.

An independently testable component with no potential common mode failure for the remaining diesel generator.

SEABROOK-UNIT 1 3/4 8-2 Amendment No. ~. gg 97