ML23310A149

Issuance of Amendment No. 227 Regarding Revision of Technical Specification 3.8.1, AC Sources - Operating, Emergency Diesel Generator Voltage and Frequency Surveillance Requirements

ML23310A149
Person / Time
Site:	Fermi
Issue date:	12/08/2023
From:	Shilpa Arora Plant Licensing Branch III
To:	Peter Dietrich DTE Electric Company
Arora S
References
EPID L-2022-LLA-0188
Download: ML23310A149 (15)

Text

December 8, 2023 Mr. Peter Dietrich Senior Vice President and Chief Nuclear Officer DTE Electric Company Fermi 2 - 260 NOC 6400 North Dixie Highway Newport, MI 48166

SUBJECT:

FERMI 2 - ISSUANCE OF AMENDMENT NO. 227 REGARDING REVISION OF TECHNICAL SPECIFICATION 3.8.1, AC SOURCES - OPERATING, EMERGENCY DIESEL GENERATOR VOLTAGE AND FREQUENCY SURVEILLANCE REQUIREMENTS (EPID L-2022-LLA-0188)

Dear Mr. Dietrich:

The U.S. Nuclear Regulatory Commission (Commission) has issued the enclosed Amendment No. 227 to Renewed Facility Operating License No. NPF-43, for Fermi 2. The amendment includes changes to the technical specification (TS) in response to your amendment request dated December 16, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22350A504), as supplemented by your letter dated May 16, 2023 (ML23136A548).

The amendment revises TS 3.8.1, AC Sources - Operating, Emergency Diesel Generator Voltage and Frequency Surveillance Requirements.

A copy of the related Safety Evaluation is also enclosed. A Notice of Issuance will be included in the Commissions monthly Federal Register notice.

Sincerely,

/RA/

Surinder S. Arora, Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-341

Enclosures:

1. Amendment No. 227 to NPF-43

2. Safety Evaluation cc: Listserv

DTE ELECTRIC COMPANY DOCKET NO. 50-341 FERMI 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 227 Renewed License No. NPF-43

1.

The U.S. Nuclear Regulatory Commission (the Commission) has found that:

A.

The application for amendment by DTE Electric Company dated December 16, 2022, as supplemented by letter dated May 16, 2023, 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.

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-43 is hereby amended to read as follows:

(2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 227, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed license. DTE Electric Company 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 the date of issuance.

FOR THE NUCLEAR REGULATORY COMMISSION Jeffrey A. Whited, Chief Plant Licensing Branch III 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 8, 2023 Jeffrey A.

Whited Digitally signed by Jeffrey A. Whited Date: 2023.12.08 07:08:57 -05'00'

ATTACHMENT TO LICENSE AMENDMENT NO. 227 FERMI 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE DOCKET NO. 50-341 Renewed Facility Operating License No. NPF-43 Replace the following page of the Renewed Facility Operating Licenses No. NPF-43 with the attached revised page. The revised page is identified by amendment number and contains marginal lines indicating the area of change.

REMOVE INSERT Technical Specifications Replace or add the following pages in Appendix A, Technical Specifications. The revised and the additional pages are identified by amendment number and contain marginal lines indicating the areas of change.

REMOVE INSERT 3.8-3 3.8-3 3.8-4 3.8-4 3.8-5 3.8-5 3.8-6 3.8-6 3.8-7 3.8-7 3.8-8 3.8-8 3.8-9 3.8-9 3.8-9a 3.8-9b Renewed License No. NPF-43 Amendment No. 227 (2)

Technical Specifications and Environmental Protection Plan The Technical Specifications contained in Appendix A, as revised through Amendment No. 227, and the Environmental Protection Plan contained in Appendix B, are hereby incorporated into this renewed license. DTE Electric Company shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

(3)

Antitrust Conditions DTE Electric Company shall abide by the agreements and interpretations between it and the Department of Justice relating to Article I, paragraph 3 of the Electric Power Pool Agreement between DTE Electric Company and Consumers Power Company as specified in a letter from the Detroit Edison Company to the Director of Regulation, dated August 13, 1971, and the letter from Richard W. McLaren, Assistant Attorney General, Antitrust Division, U.S. Department of Justice, to Bertram H. Schur, Associate General Counsel, Atomic Energy Commission, dated August 16, 1971.

(4)

Deleted (5)

Deleted (6)

Deleted (7)

Deleted (8)

Deleted (9)

Modifications for Fire Protection (Section 9.5.1, SSER #5 and SSER #6)*

DTE Electric Company shall implement and maintain in effect all provisions of the approved fire protection program as described in its Final Safety Analysis Report for the facility through Amendment 60 and as approved in the SER through Supplement No. 5, subject to the following provision:

(a)

DTE Electric Company may make changes to the approved fire protection program without prior approval of the Commission only if those changes would not adversely affect the ability to achieve and maintain safe shutdown in the event of a fire.

The parenthetical notation following the title of many license conditions denotes the section of the Safety Evaluation Report (SER) and/or its supplements wherein the license condition is discussed.

FERMI - UNIT 2 3.8-3 Amendment No. 134, 178, 183, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.1.1 Verify correct breaker alignment and indicated power availability for each offsite circuit.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.2

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NOTES-------------------

1.

All EDG starts may be preceded by an engine prelube period and followed by a warmup period prior to loading.

2.

A modified EDG start involving idling and gradual acceleration to synchronous speed may be used for this SR as recommended by the manufacturer.

Verify each EDG starts and achieves:

a.

steady state voltage 3950 V and 4314 V for Division I EDGs; and

b.

steady state voltage 3950 V and 4400 V for Division II EDGs; and

c.

steady state frequency 59.5 Hz and 60.5 Hz for both Division I and Division II EDGs.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-4 Amendment No. 134, 178, 183, 188, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.3

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NOTES-------------------

1.

EDG loadings may include gradual loading as recommended by the manufacturer.

2.

Momentary transients below the load limit do not invalidate this test.

3.

This Surveillance shall be conducted on only one EDG at a time.

Verify each EDG is synchronized and loaded and operates for 60 minutes at a load 2500 kW.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.4 Verify each day tank contains one hour supply of fuel oil.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.5 Check for and remove accumulated water from each day tank.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.6 Verify each fuel oil transfer system operates to automatically transfer fuel oil from storage tanks to the day tanks.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-5 Amendment No. 134, 140, 178, 183, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.7

---

NOTE--------------------

All EDG starts may be preceded by an engine prelube period and followed by a warmup period prior to loading.

Verify each EDG starts from standby condition and achieves:

a.

In 10 seconds, voltage 3950 V and frequency 58.8 Hz; and

b.

For steady state:

i. voltage 3950 V and 4314 V for Division I EDGs; and ii. voltage 3950 V and 4400 V for Division II EDGs; and iii. frequency 59.5 Hz and 60.5 Hz for both Division I and Division II EDGs.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.8 Verify each EDG rejects a load greater than or equal to its associated single largest post-accident load, and following load rejection, the frequency is 66.75 Hz.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.9 Verify each EDG does not trip and voltage is maintained 5267 V during and following a load rejection of 2850 kW.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-6 Amendment No. 134, 178, 183, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.10

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NOTE--------------------

All EDG starts may be preceded by an engine prelube period.

Verify on simulated loss of offsite power signal:

a.

De-energization of emergency buses;

b.

Load shedding from emergency buses; and

c.

EDG auto-starts and:

1. energizes permanently connected loads in 10 seconds,

2. energizes auto-connected shutdown loads through load sequencer,

3. maintains steady state voltage:

3950 V and 4314 V for Division I EDGs; and 3950 V and 4400 V for Division II EDGs; and

4. maintains steady state frequency:

59.5 Hz and 60.5 Hz for both Division I and Division II EDGs; and

5. supplies permanently connected and auto-connected shutdown loads for 5 minutes.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-7 Amendment No. 134, 178, 183, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.11

---

NOTE--------------------

All EDG starts may be preceded by an engine prelube period.

Verify on an actual or simulated Emergency Core Cooling System (ECCS) initiation signal each EDG auto-starts and:

a.

In 10 seconds after auto-start and during tests, achieves voltage 3950 V and frequency 58.8 Hz;

b.

Achieves steady state:

i.

voltage 3950 V and 4314 V for Division I EDGs; and ii.

voltage 3950 V and 4400 V for Division II EDGs; and iii. frequency 59.5 Hz and 60.5 Hz for both Division I and Division II EDGs; and

c.

Operates for 5 minutes.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.12 Verify each EDG's automatic trips are bypassed on an actual or simulated emergency start signal except:

a.

Engine overspeed;

b.

Generator differential current;

c.

Low lube oil pressure;

d.

Crankcase overpressure; and

e.

Failure to start.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-8 Amendment No. 134, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.13

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NOTE---------------------

Momentary transients outside the load range do not invalidate this test.

Verify each EDG operates for 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />s:

a.

For all but the final 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> loaded 2500 kW and 2600 kW; and

b.

For the final 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> of the test loaded 2800 kW and 2900 kW.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.14

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NOTES-------------------

1.

This Surveillance shall be performed within 5 minutes of shutting down the EDG after the EDG has operated 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> loaded 2500 kW or until operating temperatures have stabilized.

Momentary transients below the load limit do not invalidate this test.

2.

All EDG starts may be preceded by an engine prelube period.

Verify each EDG starts and achieves:

a.

In 10 seconds, voltage 3950 V and frequency 58.8 Hz; and

b.

For steady state:

i.

voltage 3950 V and 4314 V for Division I EDGs; and ii. voltage 3950 V and 4400 V for Division II EDGs; and iii. frequency 59.5 Hz and 60.5 Hz for both Division I and Division II EDGs.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-9 Amendment No. 134, 178, 183, 201, 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.15 Verify each EDG:

a.

Synchronizes with offsite power source while loaded with emergency loads upon a simulated restoration of offsite power;

b.

Transfers loads to offsite power source; and

c.

Returns to standby status.

In accordance with the Surveillance Frequency Control Program SR 3.8.1.16 Verify interval between each sequenced load block is within +/- 10% of design interval for each load sequencer timer.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-9a Amendment No. 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.17

---

NOTE--------------------

All EDG starts may be preceded by an engine prelube period.

Verify, on simulated loss of offsite power signal in conjunction with an actual or simulated ECCS initiation signal:

a.

De-energization of emergency buses;

b.

Load shedding from emergency buses; and

c.

EDG auto-starts and:

1.

energizes permanently connected loads in 10 seconds,

2.

energizes auto-connected emergency loads through load sequencer,

3.

achieves steady state voltage:

3950 V and 4314 V for Division I EDGs, and 3950 V and 4400 V for Division II EDGs; and

4.

achieves steady state frequency:

59.5 Hz and 60.5 Hz for both Division I and Division II EDGs; and

5.

supplies permanently connected and auto-connected emergency loads for 5 minutes.

In accordance with the Surveillance Frequency Control Program (continued)

FERMI - UNIT 2 3.8-9b Amendment No. 227 AC Sources Operating 3.8.1 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.1.18

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NOTE--------------------

All EDG starts may be preceded by an engine prelube period.

Verify, when started simultaneously each EDG achieves, in 10 seconds, frequency 58.8 Hz.

In accordance with the Surveillance Frequency Control Program

SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 227 TO RENEWED FACILITY OPERATING LICENSE NO. NPF-43 DTE ELECTRIC COMPANY FERMI 2 DOCKET NO. 50-341

1.0 INTRODUCTION

By letter dated December 16, 2022 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML22350A504), DTE Electric Company (the licensee) submitted a license amendment request (LAR) for Fermi 2 Power Plant (Fermi 2), regarding changes to Technical Specification (TS) 3.8.1, AC [alternating current] Sources - Operating. Specifically, the LAR proposes to revise Surveillance Requirements (SRs) 3.8.1.2, 3.8.1.7, 3.8.1.10, 3.8.1.11, 3.8.1.14, and 3.8.1.17, by revising the steady state voltage and frequency acceptance criteria for each emergency diesel generator (EDG).

In response to the U.S. Nuclear Regulatory Commission (NRC or Commission) staffs request for additional information, the licensee provided supplemental information by its letter dated May 16, 2023 (ML23136A548). The letter dated May 16, 2023, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the NRC staffs original proposed no significant hazards consideration determination as published in the Federal Register on February 21, 2023 (88 FR 10556).

2.0 REGULATORY EVALUATION

2.1 Description of Onsite Standby Power Sources According to the Fermi Updated Final Safety Analysis Report (UFSAR), (chapter 8) and TS Bases (B3.8.1), the Fermi Class 1E AC electrical power distribution system sources consist of the offsite power sources, and the onsite standby power sources, (i.e., EDGs). The design of the AC electrical power system provides independence and redundancy to ensure an available source of power to the engineered safety feature (ESF) systems. The Class 1E AC distribution system is divided into redundant load groups (Division I and Division II), so loss of any one group does not prevent the minimum safety functions from being performed. Each load group is connected to an offsite power supply and two EDGs.

The onsite standby power source for 4.16 kV (kilovolt) ESF buses 64B, 64C, 65E, and 65F, consists of four EDGs: EDG 11, 12, 13, and 14, respectively. ESF Buses 64B, 64C, and EDGs 11, 12, belong to Division I; and ESF Buses 64E, 64F, and EDGs 13, 14, belong to Division II.

An EDG starts automatically on a loss-of-coolant accident (LOCA) signal (i.e., low reactor water level signal or high drywell pressure signal) or on an ESF bus degraded voltage or undervoltage signal. After the EDG has started, it automatically ties to its respective bus after offsite power is tripped as a consequence of an ESF bus undervoltage or degraded voltage, independent of or coincident with a LOCA signal. The EDGs also start and operate in the standby mode without tying to the ESF bus on a LOCA signal alone. Following the trip of offsite power, load shed relays strip nonpermanent loads from the ESF bus. When the EDG is tied to the ESF bus, loads are then sequentially connected to its respective ESF bus by the automatic sequencer. The sequencing logic controls the permissive and starting signals to motor breakers to prevent overloading the EDG.

In the event of a loss of normal power, the ESF electrical loads are automatically connected to the EDGs in sufficient time to provide for safe reactor shutdown and to mitigate the consequences of a design-basis accident (DBA), such as a LOCA.

As described in the LAR, the EDG units are designed to provide AC power at 4160 V (volt) and 60 Hz (Hertz). Each EDG rating is 2850 kW (kilowatt) continuous, and 3135 kW short time (2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />). The TS 3.8.1, AC Sources - Operating, limiting condition for operation (LCO) requires two EDGs per division to be operable. This LCO includes SRs to verify that each EDG steady state voltage and frequency remain in a specified range of acceptable values under various test conditions to ensure adequate performance of ESF loads.

2.2 Proposed TS Changes

The licensee has proposed the following changes to the TS SRs (only relevant portion of SRs are provided below) which specify acceptable ranges of EDG steady state voltage and frequency. The changes are indicated with additions in bold and deletions as strike-through.

SR 3.8.1.2:

Verify each EDG starts and achieves:

a. steady state voltage 3950 V and 4580 V 4314 V for Division I EDGs; and

b. steady state voltage 3950 V and 4400 V for Division II EDGs; and

c. steady state frequency 59.5 58.8 Hz and 60.5 61.2 Hz for both Division I and Division II EDGs.

SR 3.8.1.7:

Verify each EDG starts from standby condition and achieves:

b. For steady state:

i.

voltage 3950 V and 4580 V 4314 V for Division I EDGs; and ii. voltage 3950 V and 4400 V for Division II EDGs; and iii. frequency 59.5 58.8 Hz and 60.5 61.2 Hz for both Division I and Division II EDGs.

SR 3.8.1.10: Verify on simulated loss of offsite power signal:

c. EDG auto-starts and:

3. maintains steady state voltage:

3950 V and 4580 V 4314 V for Division I EDGs; and 3950 V and 4400 V for Division II EDGs; and

4. maintains steady state frequency 59.5 58.8 Hz and 60.5 61.2 Hz for both Division I and Division II EDGs.

SR 3.8.1.11: Verify on an actual or simulated emergency core cooling system (ECCS) initiation signal each EDG auto-starts and:

b. Achieves steady state:

i. voltage 3950 V and 4580 V 4314 V for Division I EDGs; and ii. voltage 3950 V and 4400 V for Division II EDGs; and iii. frequency 59.5 58.8 Hz and 60.5 61.2 Hz for both Division I and Division II EDGs.

SR 3.8.1.14 Verify each EDG starts and achieves:

b. For steady state:

i.

voltage 3950 V and 4580 V 4314 V for Division I EDGs; and ii. voltage 3950 V and 4400 V for Division II EDGs; and iii. frequency 59.5 58.8 Hz and 60.5 61.2 Hz for both Division I and Division II EDGs.

SR 3.8.1.17: Verify, on simulated loss of offsite power [LOOP] signal in conjunction with an actual or simulated ECCS initiation signal:

c. EDG auto-starts and:

3. achieves steady state voltage:

3950 V and 4580 V 4314 V for Division I EDGs; and 3950 V and 4400 V for Division II EDGs; and

4. achieves steady state frequency:

59.5 58.8 Hz and 60.5 61.2 Hz for both Division I and Division II EDGs.

In the proposed SRs above, the maximum steady state voltage of the EDGs is lowered from the current value of 4580 V for both divisions to 4314 V (for Division I EDGs) and 4400 V (for Division II EDGs). The minimum steady state voltage of the EDGs would remain same as the current value of 3950 V for both divisions, resulting in an overall tighter band of voltage variation.

Additionally, the proposed SRs raise the minimum steady state frequency of the EDGs from 59.8 Hz to 59.5 Hz for both divisions. The maximum steady state frequency of the EDGs is lowered from 61.2 Hz to 60.5 Hz, resulting in an overall tighter band of frequency variation.

2.3 Reason for Proposed Change In the LAR, the licensee stated, in part, that, during the Fermi design basis electrical calculation revisions, TS 3.8.1 was identified as non-conservative. The calculations demonstrate that the steady state maximum voltage currently specified in the TS 3.8.1 SRs would result in terminal voltages above the industry standard maximum voltage of 110 percent rated voltage for 460 V and 4000 V motors. [According to industry standard NEMA MG 1, Section 12.44.1, AC motors can be operated successfully at rated load with a plus or minus 10 percent of the rated voltage.]

Therefore, the maximum steady state voltage specified in the SRs needs to be reduced from its current value of 4580 V, as proposed in the LAR. The licensee also determined that the steady state frequency range for EDG operability in the SRs should be reduced based on the performance of the EDG speed control equipment and the frequency load factor in the EDG loading analysis. Therefore, the steady state frequency range specified in the SRs also needs to be revised.

2.4 Regulatory Requirements The NRC staff applied the following regulations for review of the LAR:

Title 10 of Code of Federal Regulations (10 CFR) 50.36, Technical specifications, requires, in part, that TSs shall be included by applicants for a license authorizing operation of a production or utilization facility. The regulations under 10 CFR 50.36(c) require that TSs include items in five specific categories related to station operation. These categories are (1) safety limits (SLs),

limiting safety system settings, and limiting control settings; (2) limiting conditions for operations (LCO); (3) surveillance requirements (SR); (4) design features; and (5) administrative controls.

The proposed changes in this LAR relate to the SR category. The regulation under 10 CFR 50.36(c)(3) states that Surveillance requirements 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 limiting conditions for operation will be met.

The NRC staff also reviewed the LAR based on the following guidance documents:

Regulatory Guide 1.9, Revision 2 (ML12305A253), Selection, Design, and Qualification of Diesel-Generator Units Used as Standby (Onsite) Electric Power Systems at Nuclear Power Plants dated December 1979, as referenced in chapter 8, and Appendix A of the Fermi UFSAR.

WCAP-17308-NP-A, Revision 0 (ML17215A232), Treatment of Diesel Generator Technical Specification Frequency and Voltage Tolerances. This report provides methodologies to address the impact of EDG steady state frequency and voltage variation on the ESF loads.

3.0 TECHNICAL EVALUATION

In the LAR, the licensee stated that Fermi has chosen to revise the TSs to reduce allowable DG frequency and voltage tolerance to meet WCAP-17308-NP-A, Topical Report, Approach 1. The licensee mentioned in the LAR two design calculations (DC-6447 and DC-6538) for the derivation of the new TS steady state voltage and frequency values of Division I and Division II EDGs. The NRC staff audited several of the licensees design calculations, as documented in the audit report dated May 17, 2023 (ML23130A103), to verify that the proposed steady state voltage and frequency variations of EDGs are derived from the appropriate plant design calculations to ensure adequate performance of ESF loads.

3.1 EDG Steady State Allowable Voltage Variation Evaluation For the verification of EDG steady state voltage, the NRC staff audited the following design calculations:

DC-6538, Revision A, EDG Voltage and Frequency Tolerances DC-6447, Revision F, Auxiliary Power System Analysis In response to the NRC staffs request dated April 25, 2023 (ML23115A145), the licensee provided relevant pages of above calculations by the supplement dated May 16, 2023. On page 9 of DC-6538, the following is stated: The purpose of this calculation is to develop Technical Specification Allowable Values and procedural setting values for the safety-related Emergency Diesel Generator (EDG) frequency and voltage. The values developed in this calculation are based on Analytic Limit values.

Allowable values are of interest since these values are specified in TS SRs. If the Allowable values are not met during the SRs, the EDG is declared inoperable. Allowable values are bounded by the Analytic Limit values.

On pages 11, 26, and 29 of DC-6538, the following allowable and analytic limit values of EDGs are provided:

Analytic Maximum EDG steady state voltage (ALim): Div. 1 - 4314 V; Div. 2 - 4400 V Allowable (TS) Maximum EDG steady state voltage (AV): Div. 1 - 4314 V; Div. 2 - 4400 V Allowable (TS) Minimum EDG steady state voltage (AV): Div. 1 - 3950 V; Div. 2 - 3950 V Analytic Minimum EDG steady state voltage (AL): Div. 1 - 3903 V; Div. 2 - 3668 V Analytic EDG voltage values (equal or more conservative than the allowable voltage values) are based on DC-6447.

TS Allowable Maximum EDG steady state voltage On page 61 of DC-6447, the licensee calculated EDG loadings for the scenarios of LOOP/

LOCA and LOOP only. The licensee considered maximum (analytic/allowable) EDG voltage of 4314 V for Division 1, and 4400 V for Division 2. According to page 29 of DC-6538, any voltage above these voltage values, the safety-related motors can be potentially degraded (overheating and shortened life).

The NRC staff finds that EDG steady state maximum allowable voltage of 4314 V for Division 1, and 4400 V for Division 2, as proposed in the TS SRs are conservative, reasonable, and acceptable, because based on the above-mentioned calculations, the voltages to ESF loads would remain within the allowable limit of maximum plus 10 percent of the rated voltage per industry standard.

TS Allowable Minimum EDG steady state voltage According to page 62 of DC-6447, the TS allowable minimum EDG steady voltage (3950 V) for Divisions 1 and 2 are bounded by the degraded voltage relay analytic voltage limit, which according to page 58 of DC-6447, is 3873 V and 3628 V for Division 1 and Division 2, respectively.

On page 29 of DC-6538, the licensee calculated voltage lower analytic limit of EDG, Division 1, as 3903 V, by adding a margin of 30 V to Division 1 degraded voltage relay analytical limit to account for voltage drop from EDGs to ESF buses (3873+ 30 = 3903 V). Similarly, the licensee calculated voltage lower analytic limits of EDG, Division 2, as 3903 V, by adding a margin of 40 V to Division 2 degraded voltage relay analytical limit to account for voltage drop from EDGs to ESF buses (3628 + 40 = 3668 V). The licensee chose to consider TS EDG minimum allowable voltage for both divisions as 3950 V. This value provides more than adequate margin with respect to the minimum analytical limits.

The NRC staff finds that EDG steady state minimum allowable voltage of 3950 V for both Divisions 1 and 2, as proposed in the TS SRs is conservative, reasonable, and acceptable, because based on the above mentioned calculations, the voltages to ESF loads would remain above the allowable limit of minimum minus10 percent of rated voltage per industry practice.

3.2 EDG Steady State Allowable Frequency Variation Evaluation In their LAR submittal, the licensee discusses WCAP-17308-NP-A, Treatment of Diesel Generator (DG) Technical Specification Frequency and Voltage Tolerances, Revision 0, dated July 2017, which outlines several approaches that the NRC staff finds acceptable to resolve potential issues with emergency core cooling system performance stemming from allowable tolerances in DG frequency and voltage. The licensee has indicated that they have chosen to revise the TSs to reduce the allowable tolerances in diesel generator frequency to meet Topical Report, Approach 1. By complying with the WCAP through Approach 1, the licensee imposes tighter controls on the frequency and voltage of the EDGs in order to not impact ESF motor speeds assumed in the safety analyses. The licensee evaluated the proposed changes for impact on the safety-related systems, EDG loading, EDG fuel oil consumption calculations, and motor-operated valve, performance. In particular, the licensee noted that Approach 1 does not change the EDG allowable minimum frequency to a value that would promote lowering ESF motor speed as a result of the change.

In order to verify the EDG steady state frequency SR ranges proposed, the NRC staff audited the following design calculations:

DC-6538, Revision A, EDG Voltage and Frequency Tolerances DC-0758 Volume I, Revision D, CCHVAC [control center heating, ventilation, and air conditioning] System Chilled Water Pump Head DC-0182 Volume I, Revision G, RHRSW [residual heat removal service water] Mechanical Draft Cooling Towers - Post LOCA Analysis of UHS [ultimate heat sink]

DC-6447, Revision F, Auxiliary Power System Analysis

The licensee provided the relevant pages of above calculations by the supplement dated May 16, 2023. On page 9 of DC-6538, the following is stated:

The purpose of this calculation is to develop Technical Specification Allowable Values and procedural setting values for the safety-related Emergency Diesel Generator (EDG) frequency and voltage. The values developed in this calculation are based on Analytical Limit Values...

The allowable values are of interest since these values are specified in TS SRs. If the allowable limits are not met during SRs, the EDG is declared inoperable. Allowable values can be equal to or more conservative with respect to analytic limit values.

On page 10 of DC-6538, the following allowable and analytic limit values of EDGs are provided:

Analytical Limit for maximum EDG steady state frequency: 60.66 Hz Allowable Values range for EDG steady state frequency: 59.4 Hz - 60.6 Hz [+/-1% of 60 Hz]

Allowable Values [TS] range for EDG steady state frequency: 59.4 Hz - 60.5 Hz [conservative]

Analytical limit for minimum EDG steady state frequency: 59.34 Hz TS Allowable maximum EDG steady state frequency In section 5.19 of DC-0182, Volume 1, the licensee discusses the effects of EDG frequency variation on EDG loading. This section states that the frequency range is restricted to +/- 1.1 percent based on DC-6447, Volume 1 (page 61), and DC-6538, Volume 1 (page 26). The licensee noted that some EDGs may operate at overfrequency while others may operate at underfrequency but for the licensee considered overfrequency for base reference values because it is important from a EDG load control perspective in DC-6447, Volume 1. Page 24 of DC-0758, Volume 1, also discusses the impact of overspeed (increased EDG frequency) on pump performance.

The NRC staff finds that the TS allowable maximum EDG steady state frequency of 60.5 Hz is reasonable based on the discussion above. The licensee conservatively assumed that all EDGs will be overfrequency when they may operate at different frequencies along the entire allowable range (including underfrequency). The TS allowable is enveloped by the 1.1 percent range assumed in the calculation.

TS Allowable minimum EDG steady state frequency On page 16 of DC-0758, Volume 1, the licensee discusses the effects of EDG underfrequency on pump impeller speed. This section states that the pump affinity laws are applied to the vendor supplied pump curve to assess the impact of the underfrequency. Page 19 of the same calculation stated that EDG underfrequency is assumed to reduce the pump speed by 1.1 percent. As noted above, the licensee implemented Approach 1 of the WCAP, which maintains tighter controls on the EDG frequency range in order to not adversely impact the ESF motor speeds assumed in the safety analyses.

The NRC staff finds that the TS allowable minimum EDG steady state frequency of 59.5 Hz is reasonable based on the discussion above. The TS allowable is enveloped by the 1.1 percent range assumed in the calculation and is tighter than the range previously assumed in the analyses. The staff confirmed that ESF motor speeds are not lowered as a result of this change and that the licensee complied with the approved methodology in the WCAP.

4.0 TECHNICAL CONCLUSION Based on the technical evaluation provided in section 3.0 above, the NRC staff finds the licensee has adequately evaluated the impact of the proposed conservative TS SRs changes of EDGs steady state voltage and frequency on the safety-related loads fed by the EDGs. The proposed TS changes would have no impact on the continued safe operation and shutdown capability of loads fed by the EDGs. The licensee would continue to meet the regulatory requirements discussed in section 2.4, including the regulatory guidance. Therefore, the staff finds the proposed TS changes are acceptable.

5.0 STATE CONSULTATION

In accordance with the Commissions regulations, the Michigan State official was notified of the proposed issuance of the amendment on November 2, 2023. The State official did not provide any comments.

6.0 ENVIRONMENTAL CONSIDERATION

The amendment changes requirements with respect to the installation or use of facility components located within the restricted area as defined in 10 CFR, part 20, and changes the SRs. The NRC staff has determined 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, as published in the Federal Register on February 21, 2023 (88 FR 10556), and there has been no public comment on such finding.

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.

7.0 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: V. Goel, NRR N. Hansing, NRR Date of Issuance: December 8, 2023

ML23310A149 NRR-058 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DEX/EEEB/BC NRR/DEX/EMIB/BC NAME SArora SRohrer MWendell SBailey DATE 11/01/2023 11/07/2023 6/30/2023 6/20/2023 OFFICE NRR/DSS/STSB/BC OGC -NLO NRR/DORL/LPL3/BC NRR/DORL/LPL3/PM NAME MJardaneh (RElliott for)

RSiegman JWhited SArora DATE 10/13/2023 11/20/2023 12/08/2023 12/08/2023