ML24221A362

Issuance of Amendment Nos. 245 and 233 Revise Technical Specification 3.8.1, AC Sources-Operating, Surveillance Requirement 3.8.1.2, Note 3

ML24221A362
Person / Time
Site:	Prairie Island
Issue date:	09/27/2024
From:	Ballard B NRC/NRR/DORL/LPL3
To:	Conboy T Northern States Power Company, Minnesota
Ballard B, NRR/DORL/LPL3
References
EPID L-2023-LLA-0135
Download: ML24221A362 (1)

Text

September 27, 2024

Thomas Conboy Site Vice President Northern States Power Company - Minnesota Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch, MN 55089

SUBJECT:

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2 -

ISSUANCE OF AMENDMENT NOS. 245 AND 233 RE: REVISE TECHNICAL SPECIFICATION 3.8.1, AC SOURCES-OPERATING, SURVEILLANCE REQUIREMENT 3.8.1.2, NOTE 3 (EPID L-2023-LLA-0135)

Dear Thomas Conboy:

The U.S. Nuclear Regulatory Commission (NRC, the Commission) has issued the enclosed Amendment No. 245 to Renewed Facility Oper ating License No. DPR-42 and Amendment No. 233 to Renewed Facility Operating License No. DPR-60 for the Prairie Island Nuclear Generating Plant, Units 1 and 2, respectively. The amendments consist of changes to the technical specifications (TSs) in response to your application dated September 28, 2023, as supplemented by letters dated December 5, 2023, and May 22, 2024.

The amendments revise TS 3.8.1, AC [alternating current] Sources - Operating, Surveillance Requirement 3.8.1.2, Note 3, to remove details describing a modified diesel generator start and reference to manufacturers recommendations. The details regarding the modified DG start will be relocated to the TS Bases.

T. Conboy

A copy of our related safety evaluation is also enclosed. The Notice of Issuance will be included in the Commissions monthly Federal Register notice.

Sincerely,

/RA/

Brent T. Ballard, Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket Nos. 50-282 and 50-306

Enclosures:

1. Amendment No. 245 to DPR-42

2. Amendment No. 233 to DPR-60

3. Safety Evaluation

cc: Listserv NORTHERN STATES POWER COMPANY

DOCKET NO. 50-282

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 1

AMENDMENT TO RENEWED FACI LITY OPERATING LICENSE

Amendment No. 245 Renewed License No. DPR-42

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

A. The application for amendment by Northern States Power Company (NSPM, the licensee), dated September 28, 2023, as supplemented by letter(s) dated December 5, 2023, and May 22, 2024, 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.

Enclosure 1

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. DPR-42 is hereby amended to read as follows:

(2) Technical Specifications

The Technical Specifications contained in Appendix A, as revised through Amendment No. 245, are hereby incorporated in the renewed operating license. NSPM shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of the date of its issuance and shall be implemented within 90 days.

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: September 27, 2024

NORTHERN STATES POWER COMPANY

DOCKET NO. 50-306

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNIT 2

AMENDMENT TO RENEWED FACI LITY OPERATING LICENSE

Amendment No. 233 Renewed License No. DPR-60

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

A. The application for amendment by Northern States Power Company (NSPM, the licensee), dated September 28, 2023, as supplemented by letters dated December 5, 2023, and May 22, 2024, 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.

Enclosure 2

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. DPR-60 is hereby amended to read as follows:

(2) Technical Specifications

The Technical Specifications contained in Appendix A, as revised through Amendment No. 233, are hereby incorporated in the renewed operating license. NSPM shall operate the facility in accordance with the Technical Specifications.

3. This license amendment is effective as of the date of its issuance and shall be implemented within 90 days.

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: September 27, 2024

ATTACHMENT TO LICENSE AMENDMENT NOS. 245 AND 233

RENEWED FACILITY OPERATING LICENSE NOS. DPR-42 AND DPR-60

DOCKET NOS. 50-282 AND 50-306

Replace the following pages of the Renewed Facility Operating License Nos. DPR-42 and DPR-60 with the attached revised pages. The changed areas are identified by a marginal line.

Renewed Facility Operating License No. DPR-42

REMOVE INSERT

Page 3 Page 3

Renewed Facility Operating License No. DPR-60

REMOVE INSERT

Page 3 Page 3

Technical Specifications

Replace the following pages of the Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.

REMOVE INSERT

3.8.1-6 3.8.1-6

(3) Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NSPM to receive, possess, and use at any time any byproduct, source and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required;

(4) Pursuant to the Act and 10 CFR Parts 30, 40, and 70, NSPM to receive, possess and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument and equipment calibra tion or associated with radioactive apparatus or components;

(5) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to possess but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility;

(6) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to transfer byproduct materials from other job sites owned by NSPM for the purpose of volume reduction and decontamination.

C. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter l:

Part 20, Section 30.34 of Part 30, Sections 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70; is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level

NSPM is authorized to operate the facility at steady state reactor core power levels not in excess of 1677 megawatts thermal.

(2) Technical Specifications

The Technical Specifications contained in Appendix A, as revised through Amendment No. 245, are hereby incorporated in the renewed operating license.

NSPM shall operate the facility in accordance with the Technical Specifications.

(3) Physical Protection

NSPM shall fully implement and maintain in effect all provisions of the Commission-approved physical security, guard training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 27817 and 27822) and to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The combined set of plans, which contains

Renewed Operating License No. DPR-42 Amendment No. 245

(3) Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NSPM to receive, possess, and use at any time any byproduct, source and special nuclear material as sealed neutron sources for reactor startup, sealed sources for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required;

(4) Pursuant to the Act and 10 CFR Parts 30, 40, and 70, NSPM to receive, possess and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument and equipment calibra tion or associated with radioactive apparatus or components;

(5) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to possess but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility;

(6) Pursuant to the Act and 10 CFR Parts 30 and 70, NSPM to transfer byproduct materials from other job sites owned by NSPM for the purposes of volume reduction and decontamination.

C. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations in 10 CFR Chapter l:

Part 20, Section 30.34 of Part 30, Sections 50.54 and 50.59 of Part 50, and Section 70.32 of Part 70; is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level

NSPM is authorized to operate the facility at steady state reactor core power levels not in excess of 1677 megawatts thermal.

(2) Technical Specifications

The Technical Specifications contained in Appendix A, as revised through Amendment No. 233, are hereby incorporated in the renewed operating license.

NSPM shall operate the facility in accordance with the Technical Specifications.

(3) Physical Protection

NSPM shall fully implement and maintain in effect all provisions of the Commission-approved physical security, guard training and qualification, and safeguards contingency plans including amendments made pursuant to provisions of the Miscellaneous Amendments and Search Requirements revisions to 10 CFR 73.55 (51 FR 27817 and 27822) and to the authority of 10 CFR 50.90 and 10 CFR 50.54(p). The combined set of plans, which contains

Renewed Operating License No. DPR-60 Amendment No. 233 AC Sources-Operating 3.8.1

SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY

SR 3.8.1.1 Verify correct breaker alignment and indicated power In accordance with availability for each required path. the Surveillance Frequency Control Program

SR 3.8.1.2 ----------------------------NOTES--------------------------

1.Performance of SR 3.8.1.6 satisfies this SR.

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

3.A modified DG start may be used for this SR.

When modified start procedures are not used, the time, voltage, and frequency tolerances of SR 3.8.1.6 must be met.

Verify each DG starts from standby conditions and In accordance with achieves steady state voltage > 4084 V and the Surveillance

< 4400 V, and frequency > 59.5 Hz and < 60.5 Hz. Frequency Control Program

Prairie Island Unit 1 Amendment No. 245 Units 1 and 2 3.8.1-6 Unit 2 Amendment No. 233 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION

RELATED TO AMENDMENT NO. 245 TO RENEWED FACILITY

OPERATING LICENSE NO. DPR-42

AND AMENDMENT NO. 233 TO RENEWED FACILITY

OPERATING LICENSE NO. DPR-60

NORTHERN STATES POWER COMPANY

PRAIRIE ISLAND NUCLEAR GENERATING PLANT, UNITS 1 AND 2

DOCKET NOS. 50-282 AND 50-306

1.0 INTRODUCTION

By application dated September 28, 2023 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML23271A205), as supplemented by letters dated December 5, 2023 (ML23339A060), and May 22, 2024 (ML24143A198), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (NSPM, the licensee),

requested changes to the technical specifications (TSs) for Prairie Island Nuclear Generating Plant, Units 1 and 2 (Prairie Island).

The supplemental letters dated December 5, 2023, and May 22, 2024, provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the U.S. Nuclear Regulatory Commission (NRC or Commission) staffs original proposed no significant hazards consideration determination as published in the Federal Register on January 23, 2024 (89 FR 4345).

If granted, the proposed changes would revise TS 3.8.1, AC Sources - Operating, Surveillance Requirement (SR) 3.8.1.2, Note 3, to remove details describing idling and acceleration in consideration of manufacturers recommendations for the diesel generator (DG) modified start. These details regarding the modified DG start will be maintained in the TS Bases B.3.8.1 for the proposed Note 3 of SR 3.8.1.2.

2.0 REGULATORY EVALUATION

2.1 System Description

In the license amendment request (LAR) section 2.1, System Design and Operation, the licensee provided the following description of the DG systems:

Enclosure 3

Units 1 and 2 at PINGP [Prairie Island Nuclear Generating Plant] each have dedicated emergency diesel generators (referred to in TS as DGs). Each DG is automatically started by either of the following events:

a. Undervoltage, which envelopes loss of voltage, including a loss of offsite power (LOOP), or degraded voltage on the associated 4160 Volt [V] buses. Automatic starting of the DGs is initiated by a modified 2-out-of-4 voltage relay scheme on each 4160 Volt bus to which the DG is connected.

b. Initiation of a Safety Injection (SI) signal (both of the affected Units DGs start on this signal).

Loading on the DGs is analyzed for a worst-case condition as represented by a SI signal coincident with a LOOP.

The Prairie Island Updated Safety Analysis Report (USAR) section 8, Plant Electrical Systems, Subsection 8.4, Plant Standy Diesel Gener ator Systems, (ML24128A111) states, in part:

If the Reserve Auxiliary Transformers and the Cooling Tower Substation buses

[normal power sources for the safeguards buses] should fail, backup power is provided by two Emergency Diesel Generators in each unit sized and connected to serve the engineered safety features equipment of the unit. Each Emergency Diesel Generator is sized to start and carry the engineered safety features load required for the Design Basis Accident and concurrent loss of offsite power (LOOP).

The Unit 1 Emergency Diesel Generators consist of two Fairbanks Morse units each rated at 2750 kilowatts (KW) continuous (8760 hour0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br /> basis), 0.8 power factor, 900 rpm [revolution per minute], 4160 V, 3-phase, 60 Hertz.

Each Unit 1 Emergency Diesel Generator has its own independent air starting system including a motor-driven air compressor, (powered from a 480-V emergency bus) and two accumulators each of sufficient capacity to crank the engine for 20 seconds. An interconnecting header with manual valving is provided between the starting system of the two engines, to allow the air accumulators of the opposite engine to be replenished. Cranking continues until the engine starts (speed over 250 rpm) or until a predetermined time limit (10-15 seconds) has elapsed, whichever occurs first. If an engine fails to start within the predetermined time limit, a start failure alarm is initiated, and the engine control locks out, requiring manual reset.

The Unit 2 DGs consist of two tandem-drive units (gensets) manufactured by Societe Alsacienne de Constructions Mecaniques de Mulhouse (SACM), each rated at 5400 KW continuous (8760 hour0.101 days <br />2.433 hours <br />0.0145 weeks <br />0.00333 months <br /> basis), 0.8 power factor, 1200 rpm, 4160 V, 3-phase, 60 Hertz. The gensets are radiator cooled independent of the plant cooling water system.

Each Unit 2 genset has its own air starting system consisting of four independent subsystems, two per engine. Each subsystem includes an AC motor driven air compressor (powered from a 480 volt non-safeguards bus), an air dryer, and an air receiving tank. Any two of the four air receivers will start the genset within

10 seconds. Cranking continues until the genset starts (based on lube oil pressure) or until 5 seconds has elapsed, whichever occurs first. If the genset fails to start within 5 seconds, a start failure alarm is initiated and the genset control locks out, requiring manual reset.

2.2 Description of Proposed Change

The TS limiting condition for operation (LCO) 3.8.1.b requires the operability of two DGs capable of supplying the onsite 4-kV safeguards distribution system.

The SR 3.8.1.2 verifies each DG starts from standby conditions and achieves steady state voltage 4084 V and 4400 V, and frequency 59.5 Hz and 60.5 Hz. The frequency of this SR is controlled under the Surveillance Frequency Control Program. SR 3.8.1.2 includes existing Notes 1, 2, and 3.

Existing Note 3 in SR 3.8.1.2 states:

A modified DG start involving idling and gradual acceleration to synchronous speed may be used for this SR in consideration of manufacturers recommendations. When modified start procedures are not used, the time, voltage, and frequency tolerances of SR 3.8.1.6 must be met.

The LAR proposed to revise Note 3 in SR 3.8.1.2 by deleting the statements involving idling and gradual acceleration to synchronous speed, and in consideration of manufacturers recommendations, from Note 3.

Revised Note 3 would state:

A modified DG start may be used for this SR. When modified start procedures are not used, the time, voltage, and frequency tolerances of SR 3.8.1.6 must be met.

In LAR section 2.3, Reason for Proposed Changes, the licensee provided the following reason for the proposed change:

SR 3.8.1.2, Note 3, contains details that are not necessary to ensure operability; therefore, these details are not required to be in the TS to provide adequate protection of the public health and safety. Details for performing required actions and surveillances or statements providing clarification of the technical specification requirement are more appropriately specified in the TS Bases, USAR, or other licensee-controlled document that is subject to 10 CFR 50.59 or a TS requirement.

2.3 Regulatory Requirements and Guidance

Title 10 of the Code of Federal Regulations (10 CFR) section 50.36, Technical specifications, subsection (b) require, in part, the TS be derived from the analyses and evaluation included in the safety analysis report, and amendments thereto. Subsection (c) of 10 CFR 50.36 requires, in part, the TS to include items in categories including LCOs, SRs, and administrative controls.

Section 50.36(c)(3) of 10 CFR states, in part, that SRs are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the [LCOs] will be met.

Under subsection (c)(1) of 10 CFR 50.59, Changes, tests, and experiments, licensees may make changes in the facility or in the procedures as described in the final safety analysis report (as updated), without obtaining a license amendment pursuant to 10 CFR 50.90 if the licensee determines the change meets certain, specified criteria.

In the Prairie Island USAR, section 1.5, Gener al Design Criteria, the licensee stated that Prairie Island was designed and constructed to comply with their understanding of the intent of the proposed Atomic Energy Commission General Design Criteria (GDC) for Nuclear Power Plant Construction Permits, as published in t he Federal Register on July 11, 1967 (32 FR 10213), because construction of the plant was significantly completed prior to issuance of the 10 CFR Part 50, Appendix A General Design Criteria, on February 20, 1971. Prairie Island DGs comply with the intent of the following proposed GDC 39 as published in the Federal Register:

Criterion 39 - Emergency Power For Engineered Safety Features

Alternate power systems shall be provided and designed with adequate independency, redundancy, capacity, and testability to permit the functioning required of the engineered safety features. As a minimum, the onsite power system and the offsite power system shall each, independently, provide this capacity assuming a failure of a single active component in each power system.

The NRC staff used the following guidance to evaluate the proposed change:

Regulatory Guide (RG) 1.9, Application and Testing of Safety-Related Diesel Generators in Nuclear Power Plants, Revision 4 (ML070380553), provides guidance for the design, qualification, and periodic testing of DGs used as onsite electric power systems for nuclear power plants. This guidance is used to develop the SRs for DGs in general.

3.0 TECHNICAL EVALUATION

The NRC staff reviewed the proposed change to SR 3.8.1.2, Note 3, to determine the licensees compliance with applicable regulations.

3.1 Evaluation of the proposed change

Prairie Island SR 3.8.1.2 verifies that the DGs can be started from standby conditions and achieve the required steady-state voltage and frequency ranges with no time requirements.

Current Note 3 of SR 3.8.1.2 allows the option to conduct a modified DG start (slow start) involving idling and gradual acceleration to synchronous speed in consideration of manufacturers recommendations in lieu of the specified test in SR 3.8.1.2. In addition, according to the current TS Bases B 3.8.1, AC Sources-Operating, (ML24128A125) the modified DG start may be performed when it is recommended by the DG manufacturer and its purpose is to reduce stress and wear on the diesel engines. In LAR section 2.1, the licensee stated that SR 3.8.1.2 is performed on a 62-day frequency, and it helps to ensure the availability of the DGs to mitigate design bases accidents and transients and to maintain the unit in a safe shutdown condition.

In LAR section 3.0, Technical Evaluation, t he licensee proposed to delete from Note 3 of SR 3.8.1.2 details of a modified DG start such as idling, acceleration, and consideration of manufacturers recommendations. The licensee stated that (1) these details are not necessary to ensure the operability of the DGs; and (2) the licensees operating and testing procedures are

informed by factors such as design specificat ions, vendor technical manuals, and the operating experience program that has diverse inputs incl uding technical bulletins from manufacturers.

The licensee stated that the above-mentioned details are more appropriately specified in the TS Bases, USAR, or another licensee-controlled document that is subject to 10 CFR 50.59 or a TS requirement. However, the licensees initial submittal did not identify where the details would be relocated should the amendment be approved.

RG 1.9, Revision 4, describes DG tests and notes for slow-starting and reaching rated speed on a prescribed schedule to minimize DG stress and wear. This is currently implemented by SR 3.8.1.2, Note 3. The licensee may perform this slow-start test when it is consistent with the recommendations of the Prairie Island DGs manufacturers as described in TS Bases B.3.8.1.

In the letter dated November 15, 2023 (ML23304A163), and the email dated April 15, 2024 (ML24116A253), the staff requested that the licensee provide additional information about what constitutes the modified DG start in the proposed Note 3, how the licensee will ensure that the modified DG start test remains applicable to Prairie Island considering the diverse factors informing its procedure, and why the details removed from the current Note 3 were not relocated to the TS Bases.

In its response letter dated December 5, 2023, the licensee stated that the detailed steps of the modified (slow) starts are maintained in the surveillance procedures for DG modified (slow) starts, as required by TS 5.4, Procedures. The licensee stated that procedures for the Unit 1 DG modified start include approximately one minute idling time before manually raising engine speed; and the procedures for the Unit 2 DG modified start include a built-in slow test mode with a slower acceleration as part of the governor control system. The licensee explained that the procedures for a modified (slow) start for the Unit 1 and Unit 2 DGs are different because the DGs were from different manufacturers. In addition, the licensee stated that the current procedures for SR 3.8.1.2 for the Unit 1 and Unit 2 DGs will not be changed with this amendment. The licensee also stated that changes to the plant procedures are subject to 10 CFR 50.59, and, thus, information from factors informing the modified DG start procedures that is determined to be applicable to the DGs will be incorporated into the procedures for SR 3.8.1.2 in accordance with 10 CFR 50.59.

In the licensees letter dated May 22, 2024, the licensee proposed adding details of the modified DG start to the TS Bases. The TS Bases B.3.8.1 for the proposed Note 3 of SR 3.8.1.2 would state:

Note 3 of SR 3.8.1.2 allows for a modified (slow) DG start procedure. The slow DG start procedure is intended to reduce long-term stress and wear on the diesel engines and will be informed by manufacturers recommendations, operating experience, DG subject matter expertise, and other factors. The slow DG start can include idling, a longer time for acceleration, and/or other steps that are different than the fast DG start procedure of SR 3.8.1.6.

In the licensees letter dated December 5, 2023, the licensee stated that the TS Bases are subject to TS 5.5.12, Technical Specifications (TS) Bases Control Program, and, therefore, changes to the TS Bases are subject to 10 CFR 50.59. The licensee stated that changes to the TS Bases that are not consistent with t he TS cannot be made without prior NRC approval.

The NRC staff reviewed the licensees responses and finds that removing the details of the modified DG start from Note 3 and maintaining them in the TS Bases is acceptable because the

details provide an adequate summary of what is involved in the modified DG start, similar to the current Note 3, to ensure that the modified DG start will continue to achieve its purpose. In addition, since the modified DG start will continue to be performed with the current procedures for SR 3.8.1.2, as summarized in the TS Bases, the NRC staff finds that the relocation of the details in the current Note 3 to the TS Bases does not impact the SRs ability to demonstrate the capability of the DG to achieve steady-state voltage and frequency from standby conditions with a modified (slow) start in consideration of manufacturers recommendations, as currently allowed by the TS and discussed in RG 1.9 Rev.4. The staff also notes that SR 3.8.1.6 overlaps with SR 3.8.1.2, in that it requires a 10 second start to demonstrate the DGs ability to do a fast start and achieve steady state voltage and frequency. The requirement to perform SR 3.8.1.6 remains unchanged by the proposed amendment. Therefore, the staff finds that the proposed Note 3 in SR 3.8.1.2 is acceptable because SR 3.8.1.2 will continue to demonstrate the capability of the DGs to perform their safety function, as required by TS LCO 3.8.1.b. As such, 10 CFR 50.36(c)(3) is met. The NRC staff finds that adequate regulatory controls exist to ensure that the modified DG start in the proposed Note 3 continues to achieve its purpose since changes to the TS Bases and the procedures for SR 3.8.1.2 are subject to 10 CFR 50.59(c)(1).

3.2 Compliance with the general design criterion

Section 4.1.1, Principal Design Criteria, of the licensees submittal states that the proposed change has no effect on how the Prairie Island DGs comply with Criterion 39 and that no changes are proposed to the plant, the testability of the DGs, and the installed equipment.

Section 4.2 of the LAR states that the proposed change does not modify safety analysis assumptions or involve a significant reduction in the margin of safety.

Under proposed GDC 39, the DGs are to be designed with adequate independency, redundancy, capacity, and testability to permit the functioning required of the engineered safety features. Section 8 of the Prairie Island USAR states that to satisfy GDC 39, independent alternate power systems are provided with adequate capacity and testability to supply the required engineered safety features and protection systems, which includes the DGs. The TS Bases 3.8.1 states that, as required by AEC GDC Criterion 39, the design of the AC electrical system provides independence and redundancy to ensure an available source of power to the Engineered Safety Feature (ESF) systems. The TS Bases 3.8.1 also state that the operability of the DGs in TS LCO 3.8.1.b is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the unit. This results in maintaining at least one train of the onsite (DGs) or offsite AC sources operable during accident conditions in the event of an assumed loss of all offsite power and a worst-case single failure. The redundancy, capability and testability of the DGs are incorporated into the TS LCO 3.8.1.b and associated SRs. The proposed changes will not affect LCO 3.8.1, as it would still require that the two DGs capable of supplying the onsite 4kV Safeguards Distribution System be operable. The definition of OPERABLE in the Prairie Island TS states that a system, subsystem, train, component or device shall be OPERABLE or have OPERABILI TY when it is capable of performing its specified function(s) and when all necessary attendant instrumentation, controls, electrical power, cooling and seal water, lubrication, and other auxiliary equipment that are required for the system, subsystem, train, component, or device to perform its function(s) are also capable of performing their related support function(s). The specified safety function(s) for the DGs are not changed by the licensees proposed amendment. Accordingly, the DGs are still required to perform their specified safety functions described in the accident analyses in the Prairie Island USAR, and, therefore, SR 3.8.1.2 will continue to ensure that LCO 3.8.1.b is met, and as result that, proposed GDC 39 is met.

3.4 Conclusion

The NRC staff reviewed the proposed changes to TS 3.8.1, SR 3.8.1.2, Note 3 to remove details of the modified DG start and reference to manufacturers recommendations. These details regarding the modified DG state will be maintained in the TS Bases B.3.8.1 for the proposed Note 3 of SR 3.8.1.2. Based on its review, the staff finds that the proposed change is acceptable because 1) the proposed SR 3.8.1.2 assures that the necessary quality of the DGs is maintained and the TS LCO 3.8.1.b requirement for two operable DGs will be met, as required by 10 CFR 50.36(c)(3) and proposed GDC 39, and 2) changes to the procedures and TS Bases for SR 3.8.1.2 will be controlled by 10 CFR 50.59 (c)(1). Accordingly, the NRC staff finds that sufficient regulatory controls exist under the regulations and the licensees TS to ensure that the DGs will be operable and that the existing SRs are sufficient to demonstrate operability in accordance with 10 CFR 50.36(c)(3). Therefore, the details of the modified surveillance can be relocated to the Bases without a significant impact on safety.

4.0 STATE CONSULTATION

In accordance with the Commissions regulations, the Minnesota State official was notified of the proposed issuance of the amendments on August 7, 2024. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendments change the requirements with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR part 20 or change the surveillance requirements. The staff has determined that the amendments involve 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 amendments involve no significant hazards consideration and there has been no public comment on such finding (89 FR 4345). Accordingl y, the amendments meet 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 amendments.

6.0 CONCLUSION

The Commission has concluded, based on the considerations discussed above, that: (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) there is reasonable assurance that such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributor: A. Foli, NRR E. Kleeh, NRR R. Elliot, NRR

Date of Issuance: September 27, 2024

ML24221A362 NRR-058 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DEX/EEEB/BC NRR/DSS/STSB/BC NAME BBallard SRohrer WMorton SMehta DATE 8/7/2024 8/13/24 7/19/2024 8/9/2024 OFFICE OGC (NLO NRR/DORL/LPL3/BC NRR/DORL/LPL3/PM NAME NMertz JWhited BBallard DATE 9/9/2024 9/26/2024 09/27/2024