ML24157A324

Issuance of Amendment No. 254 Revision of Reactor Water Cleanup Isolation Valve Timing

ML24157A324
Person / Time
Site:	Clinton
Issue date:	07/11/2024
From:	Joel Wiebe Plant Licensing Branch III
To:	Rhoades D Constellation Energy Generation, Constellation Nuclear
Wiebe J
References
EPID L-2023-LLA-0118
Download: ML24157A324 (1)

Text

July 11, 2024

David P. Rhoades Senior Vice President Constellation Energy Generation, LLC President and Chief Nuclear Officer Constellation Nuclear 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

CLINTON POWER STATION, UN IT NO. 1 - ISSUANCE OF AMENDMENT NO. 254 RE: REVISION OF REACTO R WATER CLEANUP ISOLATION VALVE TIMING (EPID L-2023-LLA-0118)

Dear David Rhoades:

The U.S. Nuclear Regulatory Commission (Commission) has issued the enclosed Amendment No. 254 to Facility Operating License No. NPF-62 for the Clinton Power Station, Unit No. 1. The amendment is in response to your letter dated August 21, 2023, as supplemented by letter dated May 9, 2024.

The amendment revises the reactor water cleanup (RWCU) system isolation functions that are listed in Technical Specification 3.3.6.1, Primary Containment and Drywell Isolation Instrumentation, Table 3.3.6.1-1, Primary Containment and Drywell Isolation Instrumentation.

Specifically, the change increases the allowable value for Function 4.b, Differential Flow-Timer, and renames Function 4.b as Diffe rential Flow Timer - High. In addition, new functions are added for a differential flow timer - high-high trip and an associated differential flow high-high timer.

D. Rhoades

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

Sincerely,

/RA/

Joel S. Wiebe, Senior Project Manager Plant Licensing Branch III Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation

Docket No. 50-461

Enclosures:

1. Amendment No. 254 to NPF-62

2. Safety Evaluation

cc: Listserv

CONSTELLATION ENERGY GENERATION, LLC

DOCKET NO. 50-461

CLINTON POWER STATION, UNIT NO. 1

AMENDMENT TO FACILITY OPERATING LICENSE

Amendment No. 254 License No. NPF-62

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

A. The application for amendment by Constellation Energy Generation, LLC (the licensee) dated August 21, 2023, as supplemented by letter dated May 9, 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 Facility Operating License No. NPF-62 is hereby amended to read as follows:

(2) Technical Specifications and Environmental Protection Plan

The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 254, are hereby incorporated in the license. Constellation Energy Generation, LLC shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

3. This license amendment is effective as of its date of issuance and shall be implemented prior to startup from the fall 2025 refueling outage.

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 Facility Operating License and Technical Specifications

Date of Issuance: July 11, 2024

ATTACHMENT TO LICENSE AMENDMENT NO. 254

FACILITY OPERATING LICENSE NO. NPF-62

CLINTON POWER STATION, UNIT NO. 1

DOCKET NO. 50-461

Replace the following pages of the Facility Operating License No. NPF-62 and 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

Page 3 Page 3

Technical Specifications

REMOVE INSERT 3.3-59 3.3-59

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

(5) Constellation Energy Generation, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to receive, possess, and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components;

(6) Constellation Energy Generation, LLC, pursuant to the Act and 10 CFR Parts 30, 40, and 70, to possess, but not separate, such byproduct and special nuclear materials as may be produced by the operation of the facility. Mechanical disassembly of the GE14i isotope test assemblies containing Cobalt-60 is not considered separation; and

(7) Constellation Energy Generation, LLC, pursuant to the Act and 10 CFR Parts 30, to intentionally produce, possess, receive, transfer, and use Cobalt-60.

C. This license shall be deemed to contain and is subject to the conditions specified in the Commissions regulations set forth in 10 CFR Chapter I and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified or incorporated below:

(1) Maximum Power Level

Constellation Energy Generation, LLC is authorized to operate the facility at reactor core power levels not in excess of 3473 megawatts thermal (100 percent rated power) in accordance with the conditions specified herein.

(2) Technical Specifications and Environmental Protection Plan

The Technical Specifications contained in Appendix A and the Environmental Protection Plan contained in Appendix B, as revised through Amendment No. 254, are hereby incorporated into this license.

Constellation Energy Generation, LLC, shall operate the facility in accordance with the Technical Specifications and the Environmental Protection Plan.

Amendment No. 254 Primary Containment and Drywell Isolation Instrumentation 3.3.6.1

Table 3.3.6.1-1 (page 5 of 6)

Primary Containment and Drywell Isolation Instrumentation

APPLICABLE CONDITIONS MODES OR REQUIRED REFERENCED OTHER CHANNELS FROM SPECIFIED PER REQUIRED SURVEILLANCE ALLOWABLE FUNCTION CONDITIONS FUNCTION ACTION F.1 REQUIREMENTS VALUE

3. RCIC System Isolation (continued)

j. Drywell Pressure - High 1,2,3 2 I SR 3.3.6.1.1 1.88 psig SR 3.3.6.1.2 SR 3.3.6.1.3 SR 3.3.6.1.5 SR 3.3.6.1.6

k. Manual Initiation 1,2,3 1 J SR 3.3.6.1.6 NA

4. Reactor Water Cleanup (RWCU) System Isolation

a. Differential Flow - 1,2,3 2 I SR 3.3.6.1.1 66.1 gpm High SR 3.3.6.1.2 SR 3.3.6.1.6 SR 3.3.6.1.8

b. Differential Flow Timer 1,2,3 2 I SR 3.3.6.1.2 863 seconds

- High SR 3.3.6.1.4 SR 3.3.6.1.6

c. RWCU Heat Exchanger 1,2,3 2 per I SR 3.3.6.1.1 205°F Equipment Room room SR 3.3.6.1.2 Temperature-High SR 3.3.6.1.5 SR 3.3.6.1.6

d. RWCU Pump Rooms 1,2,3 2 per I SR 3.3.6.1.1 202°F Temperature-High room SR 3.3.6.1.2 SR 3.3.6.1.5 SR 3.3.6.1.6

e. Main Steam Line Tunnel 1,2,3 2 I SR 3.3.6.1.1 171°F Ambient Temperature-SR 3.3.6.1.2 High SR 3.3.6.1.5 SR 3.3.6.1.6

f. Reactor Vessel Water 1,2,3 4 I SR 3.3.6.1.1 -48.1 inches Level-Low Low, SR 3.3.6.1.2 Level 2 SR 3.3.6.1.3 SR 3.3.6.1.6 SR 3.3.6.1.8

g. Standby Liquid Control 1,2,3 2 L SR 3.3.6.1.6 NA System Initiation

h. Manual Initiation 1,2,3 2 J SR 3.3.6.1.6 NA

(c) 2 N SR 3.3.6.1.6 NA

i. Differential Flow - 1,2,3 2 I SR 3.3.6.1.1 182.4 gpm High-High SR 3.3.6.1.2 SR 3.3.6.1.6 SR 3.3.6.1.8

j. Differential Flow Timer 1,2,3 2 I SR 3.3.6.1.2 47 seconds

- High-High SR 3.3.6.1.4 SR 3.3.6.1.6

(continued)

(c) During movement of recently irradiated fuel assemblies in the primary or secondary containment.

CLINTON 3.3-59 Amendment No. 254 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION

RELATED TO AMENDMENT NO. 254 TO

FACILITY OPERATING LICENSE NO. NPF-62

CONSTELLATION ENERGY GENERATION, LLC

CLINTON POWER STATION, UNIT NO. 1

DOCKET NO. 50-461

1.0 INTRODUCTION

By letter to the U.S. Nuclear Regulatory Commission (NRC, the Commission) dated August 21, 2023 (Agencywide Documents Access and Managem ent System (ADAMS) Accession No. ML23233A168), Constellation Energy Generation, LLC (the licensee) submitted a license amendment request (LAR) for Clinton Power Station (Clinton), Unit No. 1, to revise the reactor water cleanup (RWCU) system isolation functions that are listed in Technical Specification (TS) 3.3.6.1, "Primary Containment and Drywell Isolat ion Instrumentation," Table 3.3.6.1-1, "Primary Containment and Drywell Isolation Instrumentation." Specifically, the change increases the allowable value for Function 4.b, "Differential Flow - Timer," and renames Function 4.b as "Differential Flow Timer - High." In addition, new functions are added for a differential flow -

high-high trip and an associated differential flow high - high timer. In response to a request for additional information (RAI), the licensee supplemented the LAR on May 9, 2024 (ML24130A221). The supplement provided additional information that clarified the application, did not expand the scope of the application as originally noticed, and did not change the staffs original proposed no significant hazards consideration determination as published the Federal Register on October 31, 2023 (88 FR 74529).

2.0 REGULATORY EVALUATION

2.1. System Description

The RWCU system continuously removes solid and dissolved impurities from the reactor water through filter demineralizers to maintain the purit y within specified limits. The system takes its suction within the drywell from the inlet of each reactor main recirculation pump and from the reactor pressure vessel bottom head. The process fluid is circulated with the cleanup pumps through a regenerative and nonregenerative heat exchanger for cooling, through the filter demineralizers for cleanup and back through the regenerative heat exchanger for reheating.

The regenerative and nonregenerative heat exchangers and filter demineralizers are located within the containment while the RWCU pumps are located within the auxiliary building. The processed water is returned to the reactor pressure vessel and/or the main condenser or

Enclosure 2

radwaste. Although the RWCU system is of importance to startup and long-term operation, the reactor may operate while the RWCU system is out of service.

The Updated Safety Analysis Report [USAR], Section 7.3.1.1.2.4.1.9, Reactor Water Cleanup (RWCU) System - High Differential Flow reads, in part:

High differential flow in the reactor water cleanup system could indicate a breach of the pressure boundary in the RWCU system. The RWCU system flow at the inlet to the system (suction from reactor recirculation lines) is compared with the sum of the flows at the outlets of the system (return to feedwater and flow to the Main Condenser). High differential flow initiates isolation of the RWCU system.

The RWCU system is monitored by the nuclear boiler leak detection system as described in USAR, Section 5.2.5.1, Leakage Detection Methods. The primary safety function of the leak detection system is to ensure that abnormal leakage from select systems within the primary containment and within selected areas of the plant outside the primary containment is detected, indicated, alarmed, and in certain cases isolated.

The RWCU system can be isolated by the following signals:

1. Reactor Vessel Water Level Low Low, Level 2;

2. Main Steam Tunnel Ambient Temperature High;

3. RWCU Differential Flow - High;

4. RWCU Equipment Areas (heat exchanger equi pment room or pump rooms) Ambient Temperature High;

5. Standby Liquid Control System Initiation; and

6. Manual Initiation.

Of these signals only the RWCU Differential Flow - High function is affected by the proposed TS changes contained within the LAR.

2.2 Description of the Proposed Changes

The LAR proposes the following changes to TS table 3.3.6.1, Primary Containment and Drywell Isolation Instrumentation.

The proposed change extends the allowable value for the Function 4.b, Differential Flow Timer, length from 47 seconds to 863 seconds. This time delay works in conjunction with Function 4.a, Differential Flow - High, to prevent spurious trips during most RWCU operational transients.

Due to this relationship between Functions 4.a and 4.b, the proposed change also renames Function 4.b as Differential Flow Timer - High.

In addition, the proposed change adds the following new RWCU system isolation functions.

APPLICABLE REQUIRED CONDITIONS MODES OR CHANNELS REFERENCED SURVEILLANCE ALLOWABLE FUNCTION OTHER PER FROM REQUIREMENTS VALUE SPECIFIED FUNCTION REQUIRED CONDITIONS ACTION F.1

i. Differential 1,2,3 2 I SR 3.3.6.1.1 182.4 gpm Flow - SR 3.3.6.1.2 High-High SR 3.3.6.1.6 SR 3.3.6.1.8

j. Differential 1,2,3 2 I SR 3.3.6.1.2 47 seconds Flow SR 3.3.6.1.4 Timer - SR 3.3.6.1.6 High-High

2.3 Regulatory Discussion

The regulatory requirements in Title 10 of the Code of Federal Regulations (10 CFR) 50.36(c) require that the TS include items in five specific categories related to station operation. These categories are (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operations (LCOs); (3) surveillance requirements (SRs); (4) design features; and (5) administrative controls.

Regulation 10 CFR 50.36(c)(2)(i), Limiting conditions for operation, states, in part, that TSs will include LCOs, which are the lowest functional capability or performance levels of equipment required for safe operation of the facility. Section 50.36(c)(2)(i) further states that [w]hen a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the TS until the condition can be met.

Regulation 10 CFR 50.36(c)(3), Surveillance requirements, states that [s]urveillance requirements are requirements related 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 regulations in 10 CFR, part 50, Domestic Licensing of Production and Utilization Facilities, Appendix A, General Design Criteria [GDC] for Nuclear Power Plants, includes the following GDCs applicable to the licensees LAR:

Criterion 4 - GDC 4, Environmental and dynamic effects design bases, states, in part, that structures, systems, and components important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents, including loss-of-coolant accidents.

Criterion 54 - GDC 54 Piping systems penetrating containment, states, in part, that Piping systems penetrating primary reactor containment shall be provided with leak detection, isolation, and containment capabilities having

redundancy, reliability, and performance capabilities which reflect the importance to safety of isolating these piping systems.

NUREG-1434, Revision 5, Standard Technical Spec ifications for General Electric Plants, Boiling Water Reactor-6 (ML21271A582), provides ex ample TS LCOs and acceptable remedial actions that meet the requirements in 10 CFR 50.36(c)(2)(i) for a standard plant design.

3.0 TECHNICAL EVALUATION

3.1 NRC Staff Evaluation

3.1.1 Radiological Analysis

The NRC staff performed independent radiological consequence analyses confirming the licensees conclusion that the current Clinton design basis main steam line break (MSLB) accident analysis remains bounding. More specifically, the NRC staff verified that the radiological consequences for the RWCU system leak at the exclusion area boundary, low population zone, and main control room, would be a small fraction of the current licensing basis radiological consequences for the MSLB accident. The activity available for release from the RWCU system leak is that present in the reactor coolant, with two cases (i.e., Case 1 and Case 2) based on the maximum equilibrium and pre-accident iodine spike concentrations of 0.2 Ci/gm (millicurie per gram) and 4.0 Ci/gm dose equivalent I [iodine]-131, respectively. A comparison of the current design basis MSLB accident and the RWCU system leak radiological consequences is shown in Table 3 of the LAR. The NRC staff concludes that the licensees proposed changes, as described in the August 21, 2023, LAR, are acceptable from a radiological consequence perspective because t he NRC staffs independent analysis confirmed that the radiological consequences are a small fraction of the radiological consequences of the MSLB accident as described above.

3.1.2 RWCU Isolation System Performance

3.1.2.1 High Energy Line Break (HELB)

Since the RWCU system penetrates the containment boundary, 10 CFR, part 50, appendix A, Criterion 54, requires that the system be provided with leak detection, having redundancy, reliability, and performance capabilities, which reflect the importance to safety of isolating the piping system.

USAR, Section 5.2.5, Reactor Coolant Pressure Boundary and ECCS [Emergency Core Cooling System] System Leakage Detection System indicates that abnormal leakage from the reactor water cleanup system within the primary containment and within selected areas of the plant outside the primary containment is detected, indicated, alarmed, and isolated.

The LAR proposes the following changes to the RWCU system timer for detecting and isolating large breaks. Function 4.j, Differential Flow Timer - High - High, will be added to TS Table 3.3.6.1-1, with the current Allowable Value of 47 seconds. In addition, Function 4.i, Differential Flow Timer - high - high, will be added to TS, Table 3.3.6.1-1, with an Allowable Value of 182.4 gpm (gallons per minute).

To ensure the proposed TS changes are bounded by the existing design basis analyses for a guillotine break isolated within 47 seconds, the licensee analyzed inside containment

sub-compartment response for breaks up to 182.4 gpm for 863 seconds for the main steam tunnel (MST), RWCU heat exchanger and heat exchanger valve rooms, RWCU crossover pipe tunnel, filter demineralizer holding pump room, filter demineralizer valve room, and filter demineralizer rooms. The result of the licensee s analysis indicates that peak temperatures, pressures, and differential pressures, for each zone are bounded by the large break result in the base calculation or that the structure was evaluated to ensure allowable stresses were not exceeded. Therefore, existing containment sub-compartment responses for a double-ended guillotine break remain applicable.

The NRC staff audited, via the licensees electronic portal, the calculations pertaining to HELB listed in LAR, Attachment 5, Design Analysis IP-C-0096, "Setpoint Calculation Reactor Water Cleanup (RWCU) System Isolation-Differential Flow Timers, 1E31R615A(B), and 1E31R616A(B)," Revision 0B. In particular, the staff focused on the assumptions and the methodologies contained within both calculations 3C10-0377-001 and 3C10-1182-003. After reviewing the assumptions and the methodologies contained therein the staff identified one issue that needed further clarification with a staff/licensee audit discussion.

During the audit the licensee posted calculation ATD-0278 on the electronic portal in support of a licensee/staff discussion that occurred on March 20, 2024. The calculation provides analysis of HELB within the auxiliary buildings RWCU pump rooms. In the RAI-1 response of May 9, 2024, the licensee summarized calculation ATD-0278 as follows:

Calculation ATD-0278 evaluates high energy line breaks (HELB) in the RWCU pump rooms. As stated in this calculation, the mass and energy release uses a detection time of 0.7 seconds due to ambient temperature detection to initiate valve closure. This is much faster than the differential flow time delay of 45 seconds, and therefore, is unaffected by the proposed changes to the differential flow setpoints.

The NRC staff verified congruence between the conclusions presented in LAR, Section 3.4.1, and the results of the three identified calculations.

Based on the: (a) review of the LAR; (b) review of the Clinton USAR; (c) NRC staffs audit; (d) review of the RAI response; and (e) applicable regulatory requirements, the staff concludes that with approval of the proposed TS changes to TS Table 3.3.6.1, the RWCU system will continue to satisfy the requirements of 10 CFR 50, appendix A, Criterion 54.

3.1.2.2 Internal Flooding Analysis

Meeting the requirements of 10 CFR 50, appendix A, GDC 4, ensures that the structures, systems, and components important to safety will be appropriately protected from potential flooding from liquid-carrying components in the plant.

The licensee revised Calculation 3C10-0485-001 that documents the internal flooding analysis to determine the effects of the design modification and corresponding changes to TS, Table 3.3.6.1, on the maximum flood levels in sub-compartments both inside and outside containment.

Only the RWCU line breaks inside containment credit differential flow as the means for detection and isolation of breaks. The calculation was revised to address releases corresponding to double-ended guillotine breaks (i.e., isolated by the short timer 47 seconds) and the maximum release for intermediate pipe breaks (isolated by the long timer 863 seconds). The calculation evaluates both steady state flood levels due to flow in and out of a

cubicle, and flood levels due to total released inventory. Where steady state levels are considered, the double-ended guillotine break with fast isolation is bounding due to the higher flow rates. Where total released inventory is considered, the new setpoint release is bounding due to larger volume.

The licensee provided the impact on safe shutdown equipment with updated flood levels for the plant areas (i.e., Environmental Zone Code) contained in LAR, Table 2, Environmental Zones with increased flood levels.

With respect to the flooding effects on the plants structural analysis, the licensee stated that:

the existing design basis anal yses are bounding for compartment temperature and pressure. Therefore, the RWCU compartment structures do not require re-evaluation for changes in pressure or temperature. The increased flood levels were evaluated for impacts to the RWCU cubicles structure. The evaluation determined that the structures remain qualified for design basis loads.

The NRC staff audited, via the licensees electronic portal, the calculation pertaining to internal flooding analysis listed in LAR, Attachment 5, D esign Analysis IP-C-0096, "Setpoint Calculation Reactor Water Cleanup (RWCU) System Isolation-Differential Flow Timers, 1E31R615A(B), and 1E31R616A(B)," Revision 0B. In particular, the staff focused on the assumptions and the methodologies contained within Calculation 3C10-0485-001. After reviewing the assumptions and the methodologies contained therein, the NRC staff identified one issue that needed further clarification with a staff/licensee audit discussion.

During the audit, the NRC staff inquired whether a line break in the RWCU pump rooms located in the auxiliary building could leak into the building hallway such that the water flows down the floor plugs into the ECCS cubicles? In the RAI-2 response of May 9, 2024, the licensee provided the response to this audit question:

The RWCU pump rooms do not have watertight doors, and a line break in this area could flood into the Auxiliary Building hallway. However, the floor plugs in the Auxiliary Building hallway that are above the ECCS cubicles have seals to prevent a flood from leaking down into the ECCS cubicles.

The NRC staff verified agreement between the conclusions presented in LAR, Section 3.4.2, and the results of calculation 3C10-0485-001.

Based on the: (a) review of the LAR; (b) review of the Clinton USAR; (c) NRC staffs audit; (d) review of the RAI response; and (e) applicable regulatory requirements, the staff concludes that with approval of the TS changes to TS, Table 3.3.6.1, the RWCU system will continue to satisfy the requirements of 10 CFR 50, appendix A, Criterion 4.

3.1.3 Instrumentation Setpoint Analysis

The existing leak detection system nominal trip setpoints and timer settings were determined by the General Electric (GE) Design Specification and Design Spec Data Sheet (DSDS).

This amendment does not change the existing square root converters 1E31-K602A/B, 1E31-K603A/B, 1E31-K605A/B, summer cards 1E31-K604A/B and alarm cards 1E31-N609A/B.

The differential pressure transmitters for recirculation suction 1E31-N076A/B, feedwater return 1E31-N077A/B, and condenser return, 1E31-N075A/B are replaced as part of the modification with more accurate instruments to reduce the total instrument loop uncertainty. Therefore, the existing GE DSDS will remain valid for the uncertainty of the existing and unchanged 59 gpm differential flow - high setpoint and 66.1 gpm allowable value, 45 second differential flow timer-high - high setpoint and 47 seconds allowable value.

The licensee stated that they followed ISA 67.04-1994 methodology to determine the nominal trip setpoint (NTSP) of 164.2 gpm and allowable value of 182.4 gpm for the differential flow -

high - high, the NTSP of 840 seconds and the allowable value of 863 seconds for the differential flow timer - high. The licensee presented the calculation details of these setpoints and allowable values in Attachment 4 of th is LAR, Design Analysis IP-C-0132 RWCU Di Differential Flow Setpoint Analysis for Detecting Large Leaks," Revision 0. The setpoint methodology is presented in the licensee controlled Nuclear Station Engineering Standard CI-01.00, Instrument Setpoint Calculation Methodology Revision 4.

The NRC staff examined the licensees allowable value and trip setpoint calculations and confirmed these calculations are consistent with the method suggested in ISA 67.04-1994. The uncertainty terms included in the calculation are consistent with the terms suggested in ISA 67.04-1994. The allowance between the NTSP and the allowable value equals to the loop/channel as-found tolerance (AFT L) and AFTL value accounts for the loop device drift value and calibration effect. This NTSP calculation assures that the loop trip setpoint as-found condition does not exceed the allowable value provided this loop is operable. The NRC staff finds that these calculations are consistent with the method suggested in ISA 67.04-1994 and are, therefore, acceptable.

3.2 NRC Staff Conclusion

Based on the above, the NRC staff concludes that the proposed changes to TS 3.3.6.1, Table 3.3.6.1.1 provide reasonable assurance that TS 3.3.6.1 would continue to ensure operation of the facility in a safe manner. Therefore, the NRC staff concludes that the TS 3.3.6.1 proposed changes will continue to meet 10 CFR 50.36(c)(2) and (c)(3). Based on the above technical review results, the NRC staff finds that the TS changes proposed by the LAR are acceptable.

4.0 STATE CONSULTATION

In accordance with the Commissions regulations, the Illinois State official was notified of the proposed issuance of the amendment on June 4, 2024. The State official had no comments.

5.0 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 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 i ndividual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, published in the Federal Register on October 31, 2023 (88 FR 74529), and there has been no public comment on such finding. Accordingly, the amendment meets the eligibility criteria for catego rical 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 amendment will not be inimical to the common defense and security or to the health and safety of the public.

Principal Contributors: D. Nold J. Parillo M. Li F. Forsaty A. Russell

Date of Issuance: July 11, 2024

ML24157A324 OFFICE NRR/DORL/LPL3/PM NRR/DORL/LPL3/LA NRR/DSS/STSB/BC NRR/DSS/SCPB/BC NAME JWiebe SRohrer SMehta MValentin DATE 6/4/2024 6/6/2024 6/11/2024 5/30/2024 OFFICE NRR/DRA/ARCB/BC NRR/DEX/EICB/BC NRR/DSS/SNSB/BC(A) OGC - NLO NAME KHsueh SFanta RBeaton AGhoshNaber DATE 6/1/2024 6/7/2024 6/5/2024 6/24/2024 OFFICE NRR/DORL/LPL3/BC NRR/DORL/LPL3/PM NAME JWhited JWiebe DATE 7/11/2024 7/11/2024