Text

Proposed Amendment to Revise Technical Specifications for Reactor Core Safety Limits, Fuel Assemblies, and Core Operating Limits Report Related to Framatome Gaia Fuel
	ML23145A195
Person / Time
Site:	Millstone
Issue date:	05/23/2023
From:	James Holloway; Dominion Energy Nuclear Connecticut
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML23145A193	List: ML23145A195;
References
	23-126
	Download: ML23145A195 (1)
	v • d • e

PROPRIETARY INFORMATION -WITHHOLD UNDER 10 CFR 2.390 Dominion Energy Nuclear Connecticut, Inc.

5000 Dominion Boulevard, Glen Allen, VA 23060 Dominion Energy.com May 23, 2023 U. S. Nuclear Regulatory Commission Serial No.23-126 Attention: Document Control Desk NRA/SS: RO Washington, DC 20555 Docket No. 50-423 License No. NPF-49 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.

MILLSTONE POWER STATION UNIT 3 PROPOSED AMENDMENT TO REVISE TECHNICAL SPECIFICATIONS FOR REACTOR CORE SAFETY LIMITS, FUEL ASSEMBLIES, AND CORE OPERATING LIMITS REPORT RELATED TO FRAMATOME GAIA FUEL Pursuant to 10 CFR 50.90, Dominion Energy Nuclear Connecticut, Inc. (DENC) is submitting a License Amendment Request (LAR) to revise the Technical Specifications (TS) for Millstone Power Station Unit 3 (MPS3). The proposed LAR revises the TS to support the use of Framatome GAIA fuel with M5 fuel cladding material, which is currently scheduled for insertion into the MPS3 reactor during the spring 2025 refueling outage.

The proposed TS changes include updating the Reactor Core Safety Limits (TS 2.1.1.2),

Fuel Assemblies design features (TS 5.3.1), and list of approved methodologies for the Core Operating Limits Report (COLR) (TS 6.9.1.6.b). provides DENC's description and assessment of the proposed TS changes. provides the marked-up MPS3 TS pages to reflect the proposed changes.

A site-specific Mechanical Design Licensing Report supporting the requested TS changes is provided, with proprietary and non-proprietary versions included as Attachments 3 and 4, respectively. Attachment 5 provides the Framatome Inc. Application for Withholding and Affidavit. contains information proprietary to Framatome Inc. (Framatome) and is supported by an affidavit (Attachment 5) signed by Framatome, the owner of the information.

The affidavit sets forth the basis on which the information may be withheld from public disclosure by the Commission and addresses with specificity the considerations listed in paragraph (b)(4) of Section 2.390 of the Commission's regulations. Accordingly, it is respectfully requested the proprietary information be withheld from public disclosure in accordance with 10 CFR 2.390.

The proposed amendment does not involve a Significant Hazards Consideration under the standards set forth in 10 CFR 50.92. The basis for this determination is included in . DENC has also determined that operation with the proposed changes will not result in any significant increase in the amount of effluents that may be released offsite, or any significant increase in individual or cumulative occupational radiation exposure. Therefore, the proposed amendment is eligible for categorical exclusion from an environmental assessment as set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR contains information that is being withheld from public disclosure under 10 CFR 2.390. Upon separation from Attachment 3, this letter is decontrolled.

Serial No.23-126 Docket No. 50-423 Page 2 of 3 51.22(b), no environmental impact statement or environmental assessment is needed in connection with approval of the proposed amendment.

The proposed amendment has been reviewed and approved by the station's Facility Safety Review Committee.

DENC requests approval of this LAR by May 31, 2024, with a 60-day implementation period.

In accordance with 10 CFR 50.91(b), a copy of this LAR is being provided to the State of Connecticut.

If you have any questions or require additional information, please contact Mr. Shayan Sinha at (804) 273-4687.

Sincerely, James E. Holloway Vice President - Nuclear Engineering and Fleet Support COMMONWEALTH OF VIRGINIA COUNTY OF HENRICO The foregoing document was acknowledged before me, in and for the County and Commonwealth aforesaid, today by James E. Holloway who is Vice President - Nuclear Engineering and Fleet Support of Dominion Energy Nuclear Connecticut, Inc. He has affirmed before me that he is duly authorized to execute and file the foregoing document on behalf of that company, and that the statements in the document are true to the best of his knowledge and belief.

Acknowledged before me this ~ a y ot _/vl_A_j--* 2023.

My Commission Expires: (1.,:}uA l!. LJ ZCX..3

Serial No.23-126 Docket No. 50-423 Page 3 of 3 Attachments:

1. Description and Assessment of Proposed Changes

2. Marked-up Technical Specifications Pages

3. ANP-4040P, Revision 0, Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition, Licensing Report (Proprietary)

4. ANP-4040NP, Revision 0, Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition, Licensing Report (Non-Proprietary)

5. Framatome Application for Withholding and Affidavit Commitments made in this letter: None cc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road, Suite 105 King of Prussia, PA 19406-1415 Richard V. Guzman Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station Director, Radiation Division Department of Energy and Environmental Protection 79 Elm Street Hartford, CT 06106-5127

Serial No.23-126 Docket No. 50-423 Page 1 of 15 Attachment 1 DESCRIPTION AND ASSESSMENT OF PROPOSED CHANGES Dominion Energy Nuclear Connecticut, Inc.

Millstone Power Station Unit 3

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 2 of 15 1.0

SUMMARY

DESCRIPTION Pursuant to 10 CFR 50.90, Dominion Energy Nuclear Connecticut, Inc. (DENC) is submitting a License Amendment Request (LAR) to revise the Technical Specifications (TS) for Millstone Power Station Unit 3 (MPS3). The proposed LAR revises the TS to support the use of Framatome GAIA fuel with M5TM1 fuel cladding material, which is currently scheduled for onload at MPS3 during the spring 2025 refueling outage. The proposed TS changes include updating the Reactor Core Safety Limits (TS 2.1.1.2), the Fuel Assembly design features (TS 5.3.1), and the list of approved methodologies for the Core Operating Limits Report (COLR) (TS 6.9.1.6.b).

2.0 DETAILED DESCRIPTION 2.1. System Design and Operation The proposed change is relevant to the mechanical, thermal-mechanical, and thermal-hydraulic design features of the reactor core fuel assemblies. FSAR Sections 4.2 and 4.4 discuss the current fuel assembly design, fuel rod methodologies, mechanical design limits, fuel centerline temperature melt limit, and applicable cladding for the current fuel product at MPS3. The proposed change supports a MPS3 transition to the Framatome GAIA fuel product with M5 fuel cladding. The GAIA fuel assembly design is generically approved by the NRC in Reference 1.

Attachments 3 and 4 summarize the mechanical, thermal-mechanical, and thermal-hydraulic analyses that support the future operation of the Framatome GAIA fuel with M5 cladding at MPS3.

2.2. Current Technical Specifications Requirements TS 2.1.1 Reactor Core Safety Limits The current MPS3 Reactor Core Safety Limits are established for Westinghouse fuel.

2.1.1.2 The peak fuel centerline temperature shall be maintained less than 5080°F, decreasing by 9°F per 10,000 MWD/MTU of burnup.

1 M5 is a trademark or registered trademark of Framatome or its affiliates, in the USA or other countries.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 3 of 15 TS 5.3 Reactor Core Design Features The current MPS3 reactor core design features are established for fuel assemblies with zircaloy-4, ZIRLO, or Optimized ZIRLOTM as the fuel cladding.

Additional information regarding fuel reconstitution is provided in TS 5.3.1.

5.3.1 The core shall contain 193 fuel assemblies. Each fuel assembly shall consist of 264 zircaloy-4, ZIRLO, or Optimized ZIRLOTM clad fuel rods with an initial composition of natural uranium dioxide or a maximum nominal enrichment of 5.0 weight percent U-235 as fuel material.

Limited substitutions of zircaloy-4, ZIRLO or stainless steel filler rods for fuel rods, in accordance with NRC-approved applications of fuel rod configurations, may be used. Fuel assembly configurations shall be limited to those fuel designs that have been analyzed with applicable NRC staff-approved codes and methods, and shown by test or cycle-specific reload analyses to comply with all fuel safety design bases. Each fuel rod shall have a nominal active fuel length of 144 inches. A limited number of lead test assemblies that have not completed representative testing may be placed in nonlimiting core regions.

TS 6.9.1.6.b Core Operating Limits Report TS 6.9.1.6 requires core operating limits to be established for each reload cycle and contains references to the approved analytical methods used to determine the core operating limits. The TS 6.9.1.6.b COLR reference list includes documents that define the methods used to determine the core operating limits for MPS3. The existing TS 6.9.1.6.b references governing fuel rod and assembly design criteria related to TS 3.2.2.1 (Heat Flux Hot Channel Factor) for the current Westinghouse fuel product are:

10. WCAP-12610, VANTAGE+ Fuel Assembly Report, (W Proprietary).

(Methodology for Specification 3.2.2.1 - Heat Flux Hot Channel Factor.)

19. WCAP-12610-P-A & CENPD-404-P-A, Addendum 1-A, Optimized ZIRLOTM, (W Proprietary). (Methodology for Specification 3.2.2.1 - Heat Flux Hot Channel Factor.)

TS 6.9.1.6.b requires that the cycle-specific COLR contain the complete identification for each of the TS referenced topical reports used (i.e., report number, title, revision, date, and any supplements).

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 4 of 15 2.3. Reason for the Proposed Changes The proposed TS changes are needed to support the transition to Framatome GAIA fuel with M5 cladding at MPS3. DENC and Framatome have entered into an agreement for batch implementation of the GAIA fuel at MPS3. A full reload batch of GAIA fuel assemblies is planned for initial use in Cycle 24, which is currently scheduled to begin operation in the spring of 2025.

2.4. Description of Proposed Changes Markups of the proposed TS changes are provided in Attachment 2. A description of the proposed changes is provided below. Additions to the TS are shown with bold highlighted text.

TS 2.1.1 Reactor Core Safety Limits This LAR revises TS 2.1.1.2 to clarify that the existing TS is a Westinghouse-specific Safety Limit for peak fuel centerline temperature. The Westinghouse-specific Safety Limit for peak fuel centerline temperature is unchanged. This LAR adds the Framatome-specific Safety Limit for peak fuel centerline temperature, based on the COPERNIC fuel rod performance code [Reference 5], to TS 2.1.1.2.

The revised TS is shown below.

2.1.1.2 For Westinghouse fuel, the peak fuel centerline temperature shall be maintained less than 5080°F, decreasing by 9°F per 10,000 MWD/MTU of burnup. For Framatome fuel, the peak fuel centerline temperature shall be maintained less than 4901°F, decreasing linearly by 13.7°F per 10,000 MWD/MTU of burnup.

The addition of this Framatome Safety Limit ensures continued compliance with the requirements of 10 CFR 50.36.

TS 5.3 Reactor Core Design Features This LAR revises the fuel assembly description to include M5 as an allowed cladding material. This change is necessary to support the use of M5 fuel cladding material with the GAIA fuel assembly.

5.3.1 The core shall contain 193 fuel assemblies. Each fuel assembly shall consist of 264 fuel rods (with zircaloy-4, ZIRLO, Optimized ZIRLOTM, or M5TM cladding) with an initial composition of natural uranium dioxide or a maximum nominal enrichment of 5.0 weight percent U-235 as fuel material.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 5 of 15 Limited substitutions of zircaloy-4, ZIRLO, M5TM, or stainless steel filler rods for fuel rods, in accordance with NRC-approved applications of fuel rod configurations, may be used. Fuel assembly configurations shall be limited to those fuel designs that have been analyzed with applicable NRC staff-approved codes and methods, and shown by test or cycle-specific reload analyses to comply with all fuel safety design bases. Each fuel rod shall have a nominal active fuel length of 144 inches. A limited number of lead test assemblies that have not completed representative testing may be placed in nonlimiting core regions.

TS 6.9.1.6.b Core Operating Limits Report This LAR revises the TS 6.9.1.6.b COLR reference list to include the Framatome-developed GAIA fuel Topical Report. TS 6.9.1.6.b requires that the cycle-specific COLR contain the complete identification for each of the TS referenced topical reports used (i.e., report number, title, revision, date, and any supplements),

therefore, only high-level reference to the applicable topical reports is provided in the TS 6.9.1.6.b list.

10. WCAP-12610, VANTAGE+ Fuel Assembly Report, (W Proprietary).

(Methodology for Specification 3.2.2.1 - Heat Flux Hot Channel Factor.)

19. WCAP-12610-P-A & CENPD-404-P-A, Addendum 1-A, Optimized ZIRLOTM, (W Proprietary). (Methodology for Specification 3.2.2.1 -

Heat Flux Hot Channel Factor.)

27. ANP-10342-P-A, GAIA Fuel Assembly Mechanical Design, (Framatome Proprietary). Methodology for Specification:

3.2.2.1 Heat Flux Hot Channel Factor TS 6.9.1.6.b will retain the Westinghouse Topical Reports to support the current MPS3 fuel product during the transition to GAIA.

Note: Reference 6 has requested NRC approval of the addition of new TS 6.9.1.6.b COLR references 24, 25, and 26. Therefore, this LAR is requesting the addition of new COLR reference 27. The numbering sequencing will be confirmed based on the sequence of Amendment issuance.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 6 of 15

3.0 TECHNICAL EVALUATION

3.1. Mechanical Design Report In support of planned implementation of the Framatome GAIA fuel design with M5 fuel cladding at MPS3, Framatome developed a Mechanical Design Report that provides design-related inputs for the Mechanical, Thermal-Mechanical, and Thermal-Hydraulic evaluations. Proprietary and Non-Proprietary versions of the Mechanical Design Report are contained in Attachments 3 and 4, respectively.

These fuel design analyses and evaluations follow the content of the NRC-approved generic Topical Report ANP-10342-P-A [Reference 1] as applied to MPS3 (Attachments 3 and 4) and confirm that the GAIA fuel assembly will maintain mechanical integrity during future MPS3 operation. The analyses and evaluations performed to verify the adequacy of the GAIA fuel design at MPS3 were for normal operation and anticipated operation occurrences (AOOs). The fuel design analyses and evaluations have confirmed that all fuel-related design criteria will be met with acceptable margins.

Section 4.0 of Attachments 3 and 4 includes a discussion of compliance with the limitations contained in the NRC Safety Evaluations (SEs) associated with the GAIA fuel design. Section 4.10.3 of Attachment 3 discusses and justifies a change to the COBRA-FLX Topical Report [Reference 4]. With this change, DENC concludes that the application of the ANP-10342-P-A methodology [Reference 1] at MPS3 complies with all applicable SE limitations and regulatory criteria.

Previous Lead Test Assembly (LTA) and reload operational experience (Section 3.0 of Attachment 3) show the GAIA fuel assembly meets the Reference 1 design criteria.

The MPS3 demonstration analyses and evaluations for GAIA fuel (Section 5.0 of Attachments 3 and 4) show the design criteria are met at MPS3. DENC concludes that the future GAIA fuel transition at MPS3 will comply with all applicable SE limitations.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 7 of 15 3.2. Technical Specification Changes TS 2.1.1 Reactor Core Safety Limits General Design Criteria (GDC) 10 requires that specified fuel design limits are not exceeded during steady state operation, normal operational transients, and AOOs.

The Safety Limits prevent overheating of the fuel and cladding, as well as possible cladding perforation, which would result in the release of fission products to the reactor coolant. Overheating of the fuel is prevented by maintaining the steady state peak linear heat rate (LHR) below the level at which fuel centerline melting occurs.

The Framatome fuel centerline temperature limit reflects a bounding treatment of uncertainty based on the COPERNIC fuel rod performance code and its corresponding methodology [Reference 5]. This limit is applicable to normal operations and AOOs. This LAR updates the peak fuel centerline temperature to include the Framatome fuel Safety Limit to ensure continued compliance with the requirements of 10 CFR 50.36.

Table 3-1 of ANP-10342-P [Reference 1] provides the Acceptance Criteria Matrix describing how the Framatome GAIA fuel design meets the acceptance criteria of NUREG-0800, Standard Review Plan (SRP), Section 4.2. Attachments 3 and 4 document how the ANP-10342-P methodology will be applied at MPS3 to evaluate SRP Section 4.2 acceptance criteria for GAIA fuel.

TS 5.3 Reactor Core Design Features The use of M5 nuclear fuel cladding material in PWR reactor fuel was approved by the NRC in Topical Report BAW-10227-P-A [Reference 2] and its use in Framatome methods was generically approved in Reference 3. The M5 cladding is a Framatome proprietary material composed of zirconium and niobium. This composition has demonstrated superior corrosion resistance and reduced irradiation induced growth relative to both standard and low-tin zircaloy. The resulting alloy microstructure is highly stable under irradiation and provides improved in-reactor thermal and mechanical performance over other zirconium alloys.

A 10 CFR 50.46 and 10 CFR 50, Appendix K exemption request for the implementation of M5 fuel rod cladding has been submitted in a separate request for NRC approval [Reference 6].

TS 6.9.1.6.b Core Operating Limits Report Section 4.0 of Attachments 3 and 4 describe the licensing basis supporting the use of ANP-10342-P-A [Reference 1] at MPS3. ANP-10342-P-A was NRC-approved for use in all Westinghouse three- and four-loop reactors using a 17x17 fuel rod array.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 8 of 15 ANP-10342-P-A is the governing licensing document for GAIA fuel and establishes the Specified Acceptable Fuel Design Limits (SAFDLs) that address the regulatory acceptance criteria and design limits. DENC concludes that the GAIA fuel design complies with all applicable SE limitations and regulatory criteria.

The current COLR references governing fuel rod and assembly design criteria (Section 2.2) establish the TS 3.2.2.1 core operating limits. ANP-10342-P-A is added to the Core Operating Limits Report list of approved methodologies and is applicable to TS 3.2.2.1 (Heat Flux Hot Channel Factor).

4.0 REGULATORY EVALUATION

4.1. Applicable Regulatory Requirements and Criteria The regulatory requirements and/or guidance documents associated with this LAR include the following:

10 CFR 50.36 - Technical Specifications 10 CFR 50.36(c) requires the TS includes items in the following specific categories: (1) safety limits, limiting safety systems settings, and limiting control settings; (2) limiting conditions for operation, (3) surveillance requirements; (4) design features; and (5) administrative controls. This LAR describes the manner in which the 10 CFR 50.36 requirements continue to be met through the specification of appropriate safety limits, limiting conditions for operation, design feature descriptions, and establishment of administrative controls. The evaluations described in Attachments 3 and 4 support the demonstration of the adequacy of the proposed TS changes.

NRC Generic Letter (GL) 88-16 NRC GL 88-16 states that it is acceptable for licensees to control reactor physics parameter limits by specifying an NRC-approved calculation methodology. These parameter limits may be removed from the TS and placed in a cycle-specific COLR, which is required to be submitted to the NRC every operating cycle or each time it is revised.

TS 6.9.1.6.b identifies the NRC-approved analytical methodologies that are used to determine the core operating limits for MPS3. The guidance in NRC GL 88-16 continues to be met since the proposed changes will continue to specify NRC-approved methodologies used to determine the core operating limits.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 9 of 15 Standard Review Plan (SRP) Chapter 4 (Reactor) and 10 CFR 50, Appendix A, General Design Criterion (GDC) 10 SRP Section 4.2 (Fuel System Design) describes all fuel damage criteria. SRP Section 4.3 (Nuclear Design) establishes criteria for core power distribution, reactivity coefficients, and reactivity control requirements. SRP Section 4.4 (Thermal and Hydraulic Design) provides specific thermal-hydraulic criteria for the core and reactor coolant system.

SRP Section 4.2 requires a fuel system safety review to provide assurance that (1) the fuel system is not damaged as a result of normal operation and anticipated operational occurrences (AOOs), (2) fuel system damage is never so severe as to prevent control rod insertion when it is required, (3) the number of fuel rod failures is not underestimated for postulated accidents, and (4) coolability is always maintained.

GDC 10 establishes specified acceptable fuel design limits (SAFDLs) that should not be exceeded during any condition of normal operation, including the effects of AOOs. SAFDLs are established to ensure fuel is not damaged (i.e., fuel rods do not fail, fuel system dimensions remain within operational tolerances, and functional capabilities are not reduced below those assumed in the safety analysis).

Compliance with GDC 10 provides assurance that the integrity of the fuel and cladding will be maintained, thus preventing the potential for release of fission products during normal operation or AOOs.

Reference 1 provides the basis for the NRC-approved SAFDLs that address the Acceptance Criteria defined in SRP Section 4.2. In addition, SRP Sections 4.3 and 4.4, and GDC 10 criteria were also reviewed. Attachments 3 (proprietary) and 4 (non-proprietary) provide descriptions of the mechanical, thermal-mechanical, and thermal-hydraulic evaluations performed for the GAIA fuel design. DENC has determined that the proposed changes meet the current regulatory requirements, and all design criteria are met under normal, upset, and faulted operating conditions.

There are no changes being proposed in this LAR that would challenge the conformance or commitments to regulatory and/or guidance documents described above. The evaluations documented herein confirm that MPS3 will continue to comply with all applicable regulatory requirements.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 10 of 15 4.2. Precedents The following fuel transition licensing activities have involved NRC review of the use of GAIA fuel or the use of M5 fuel cladding:

Dominion Energy submitted an LAR to transition to Framatome ANP Advanced Mark-BW fuel with M5 fuel cladding at North Anna Power Station, which was approved by the NRC (ADAMS Accession Nos. ML042330659 and ML040960040) in 2004. North Anna TS 2.1 (fuel centerline temperature), 4.2.1 (fuel assemblies), and 5.6.5 (COLR methodologies) were updated to support the use of Advanced Mark-BW fuel and M5 cladding at North Anna.

Dominion Energy submitted an LAR to revise Millstone Power Station Unit 2 (MPS2)

TS 6.9.1.8.b (COLR methodologies) to add the M5 topical report to the list of approved documents. The addition of the M5 topical report was approved by the NRC (ADAMS Accession No. ML15093A441) in 2015 and allowed MPS2 to use the M5 cladding as a fuel rod cladding material.

Arizona Public Service submitted an LAR to transition to Framatome Advanced Combustion Engineering 16x16 HTP fuel with M5 as a fuel rod cladding material for all three units at the Palo Verde Nuclear Generating Station, which was approved by the NRC (ADAMS Accession No. ML20031C947) in 2020. Palo Verde TS 2.1.1 (fuel centerline temperature), 4.2.1 (fuel assemblies), and 5.6.5 (COLR methodologies) were updated to support the use of HTP fuel and M5 cladding at Palo Verde.

Ameren Missouri submitted an LAR to allow the use of a limited number of GAIA fuel assemblies at Callaway Plant Unit 1 (ADAMS Package No. ML22285A115), which was accepted for review by the NRC in 2022 (ADAMS Accession No. ML22348A116). Callaway TS 2.1.1 (fuel centerline temperature) and 4.2.1 (fuel assemblies) are requested to be updated to support the use of GAIA fuel assemblies with M5 cladding at Callaway.

4.3. No Significant Hazards Consideration Dominion Energy Nuclear Connecticut, Inc. (DENC) proposes a change to Millstone Power Station Unit 3 (MPS3) Technical Specifications (TS) 2.1.1.2, 5.3.1, and 6.9.1.6.b to support the use of Framatome GAIA fuel with M5 fuel cladding. The proposed TS changes include updating the Reactor Core Safety Limits (TS 2.1.1.2),

the Fuel Assembly design features (TS 5.3.1), and the list of approved methodologies for the Core Operating Limits Report (COLR) (TS 6.9.1.6.b). DENC has evaluated

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 11 of 15 whether a significant hazards consideration is involved with the proposed amendment, and a significant hazards evaluation was performed by focusing on the three standards set forth in 10 CFR 50.92, Issuance of Amendment, as discussed below:

1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No The proposed amendment modifies the TS to: (1) include Framatome-specific safety limits, (2) utilize Framatome methods for establishing core operating limits, and (3) allow the use of M5 fuel cladding material.

Proposed change (1) incorporates a new MPS3 TS safety limit for peak fuel centerline temperature for Framatome fuel based on the COPERNIC fuel rod performance code. This limit, which is based on NRC reviewed and approved correlations, does not require physical changes to plant systems, structures, or components (SSCs) for implementation. Plant operations and analysis will continue to be in accordance with the MPS3 licensing basis. This change does not impact any of the accident indicators. The peak fuel centerline temperature is a basis for protecting the fuel and is consistent with the safety analysis.

The proposed safety limit ensures fuel integrity will be maintained during normal operations and anticipated operational transients. The proposed safety limit value and supporting TS methodologies do not affect the performance of any equipment used to mitigate the consequences of an analyzed accident.

Proposed change (2) adds a new TS method for establishing core operating limits. The Framatome method governing GAIA fuel rod and assembly design criteria is incorporated into the TS Core Operating Limits Report (COLR) list.

This fuel methodology establishes the Specified Acceptable Fuel Design Limits (SAFDLs) to ensure fuel is not damaged or functional capabilities are not reduced below those assumed in the safety analysis. The proposed change does not impact the accident indicators and does not alter any assumptions regarding assumed release pathways to the environment.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 12 of 15 Proposed change (3) allows the use of M5 cladding material which has been previously evaluated and approved for use in pressurized water reactors.

Analysis demonstrates the suitability of the cladding material and its ability to satisfy regulatory performance criteria during normal operation, anticipated operational occurrences, and postulated accidents. The presence of this material has no direct cause and effect relationship with the initiation of any evaluated accident and does not alter or prevent the ability of SSCs from performing their intended functions to mitigate the consequences of an initiating event within the assumed acceptance limits.

Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The proposed amendment modifies the TS to: (1) include Framatome-specific safety limits, (2) utilize Framatome methods for establishing core operating limits, and (3) allow the use of M5 fuel cladding material.

Proposed changes (1) and (2) do not result in any new or different accidents.

These two proposed changes do not involve a physical alteration of the plant or plant systems (i.e., no new or different type of equipment will be installed which would create a new or different kind of accident). The parameters within which the plant is normally operated are not altered, and the proposed changes do not impose any new or different operating requirements.

Proposed change (3) does not introduce any new accident initiators and does not adversely affect the performance of any SSC previously credited for accident mitigation. Use of M5 material as cladding in the MPS3 core is compatible with the plant design and does not introduce any new safety functions for plant SSCs. Analysis demonstrates the suitability of the cladding material and its ability to satisfy regulatory performance criteria during normal operation, anticipated operational occurrences, and postulated accidents.

The presence of this material has no direct cause and effect relationship with the initiation of any evaluated accident. The parameters within which the plant is normally operated are not altered, and the proposed change does not impose any new or different operating requirements.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 13 of 15 Therefore, it is concluded that the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

The proposed amendment modifies the TS to: (1) include Framatome-specific safety limits, (2) utilize Framatome methods for establishing core operating limits, and (3) allow the use of M5 fuel cladding material. The margin of safety is established through equipment design, operating parameters, and the setpoints at which automatic actions are initiated.

For proposed change (1), the COPERNIC peak fuel centerline safety limit provides assurance that Framatome fuel fission product barriers will perform within applicable acceptance criteria for normal operation, anticipated operational occurrences, and postulated accidents. No reduction in the margin of safety occurs with this proposed change.

For proposed change (2), approved methodologies, including the additional Framatome methodology in the COLR, will be used to ensure the plant continues to meet applicable design criteria and safety analysis acceptance criteria. The reactor will continue operate within its analyzed operating and design envelope. Thus, no reduction in the margin of safety occurs with this proposed change.

For proposed change (3), there is not a significant reduction in the margin of safety because it has been demonstrated that the material properties of the M5 cladding are not significantly different from those of current MPS3 fuel cladding materials. M5 is expected to perform similarly to current fuel cladding materials for normal operation, anticipated operational occurrences, and postulated accidents. All required safety limits will continue to be analyzed using methodologies approved by the NRC.

Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 14 of 15 Based on the above information, DENC concludes that the proposed change does not involve a significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.

4.4. Conclusions Based on the considerations presented above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the requested license amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 Environmental Considerations The proposed license amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion from an environmental assessment as set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.

6.0 References

1. Framatome Topical Report, ANP-10342-P-A, Revision 0, GAIA Fuel Assembly Mechanical Design, September 2019.

2. Framatome Topical Report, BAW-10227-P-A, Revision 1, Evaluation of Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel, June 2003.

3. Framatome Topical Report, BAW-10240-P-A, Revision 0, "Incorporation of M5TM Properties in Framatome ANP Approved Methods, May 2004.

4. Framatome Topical Report, ANP-10311-P-A, Revision 1, COBRA-FLX: A Core Thermal-Hydraulic Analysis Code, October 2017.

5. Framatome Topical Report, BAW-10231-P-A, Revision 1, COPERNIC Fuel Rod Design Computer Code, January 2004.

Serial No.23-126 Docket No. 50-423 Attachment 1, Page 15 of 15

6. Letter to the NRC from Dominion Energy, Serial No.23-105, Dominion Energy Nuclear Connecticut, Inc., Millstone Power Station Unit 3, License Amendment Request to Use Framatome Small Break and Realistic Large Break Loss of Coolant Accident Evaluation Methodologies for Establishing Core Operating Limits and Exemption Request for Use of M5TM Cladding, May 2, 2023.

Serial No.23-126 Docket No. 50-423 Page 1 of 5 Attachment 2 MARKED-UP TECHNICAL SPECIFICATIONS PAGES Dominion Energy Nuclear Connecticut, Inc.

Millstone Power Station Unit 3

Serial No.23-126 Docket No. 50-423 Attachment 2, Page 2 of 5 November 9, 2021 2.0 SAFETY LIMITS AND LIMITING SAFETY SYSTEM SETTINGS 2.1 SAFETY LIMITS REACTOR CORE 2.1.1 The combination of THERMAL POWER, Reactor Coolant System highest loop average temperature, and pressurizer pressure shall not exceed the limits specified in the CORE OPERATING LIMITS REPORT; and the following Safety Limits shall not be exceeded:

2.1.1.1 The departure from nucleate boiling ratio (DNBR) shall be maintained greater than or equal to 1.14 for the WRB-2M DNB correlation.

2.1.1.2 The peak fuel centerline temperature shall be maintained less than 5080qF, For Westinghouse decreasing by 9qF per 10,000 MWD/MTU of burnup. For Framatome fuel, the fuel, the peak fuel centerline APPLICABILITY: MODES 1 and 2. temperature shall be maintained less than 4901° ACTION: F, decreasing linearly by 13.7°F per 10,000 MWD/

Whenever the Reactor Core Safety Limit is violated, restore compliance and beMTU in HOT of burnup.

STANDBY within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

REACTOR COOLANT SYSTEM PRESSURE 2.1.2 The Reactor Coolant System pressure shall not exceed 2750 psia.

APPLICABILITY: MODES 1, 2, 3, 4, and 5.

ACTION:

MODES 1 and 2:

Whenever the Reactor Coolant System pressure has exceeded 2750 psia be in HOT STANDBY with the Reactor Coolant System pressure within its limit within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months .

MODES 3, 4 and 5:

Whenever the Reactor Coolant System pressure has exceeded 2750 psia, reduce the Reactor Coolant System pressure to within its limit within 5 minutes.

MILLSTONE - UNIT 3 2-1 Amendment No. 173, 217, 236, 242, 281, 280

Serial No.23-126 Docket No. 50-423 Attachment 2, Page 3 of 5 September 24, 2012 DESIGN FEATURES 5.3 REACTOR CORE (with zircaloy-4, ZIRLO, Optimized ZIRLO' , or FUEL ASSEMBLIES M5TM cladding) 5.3.1 The core shall contain 193 fuel assemblies. Each fuel assembly shall consist of 264 zircaloy-4, ZIRLO, or Optimized ZIRLO' clad fuel rods with an initial composition of natural uranium dioxide or a maximum nominal enrichment of 5.0 weight percent U-235 as fuel material.

Limited substitutions of zircaloy-4, ZIRLO or stainless steel filler rods for fuel rods, in accordance with NRC-approved applications of fuel rod configurations, may be used. Fuel assembly configurations shall be limited to those fuel designs that have been analyzed with applicable NRC staff-approved codes and methods, and shown by test or cycle-specific reload analyses to comply with all fuel safety design bases. Each fuel rod shall have a nominal active fuel length of 144 inches. A limited number of lead test assemblies that have not completed representative testing may be placed in nonlimiting core regions.

, M5TM, CONTROL ROD ASSEMBLIES 5.3.2 The core shall contain 61 full-length control rod assemblies. The full-length control rod assemblies shall contain a nominal 142 inches of absorber material. The nominal values of absorber material shall be 95.3% hafnium and 4.5% natural zirconium or 80% silver, 15% indium, and 5% cadmium. All control rods shall be clad with stainless steel.

5.4 DELETED 5.5 DELETED MILLSTONE - UNIT 3 5-5 Amendment No. 12, 37, 81, 212, 253

Serial No.23-126 Docket No. 50-423 Attachment 2, Page 4 of 5 October 5, 2021 ADMINISTRATIVE CONTROLS CORE OPERATING LIMITS REPORT (Cont.)

23. DOM-NAF-2-P-A, Reactor Core Thermal-Hydraulics Using the VIPRE-D Computer Code, including Appendix C, Qualification of the Westinghouse WRB-2M CHF Correlation in the Dominion VIPRE-D Computer Code, and Appendix D, Qualification of the ABB-NV and WLOP CHF Correlations in the Dominion VIPRE-D Computer Code. Methodology for Specifications:

3.2.3.1 RCS Flow Rate, Nuclear Enthalpy Rise Hot Channel Factor

3.2.5 DNB Parameters INSERT A 6.9.1.6.c The core operating limits shall be determined so that all applicable limits (e.g. fuel thermal-mechanical limits, core thermal-hydraulic limits, ECCS limits, nuclear limits such as SHUTDOWN MARGIN, and transient and accident analysis limits) of the safety analysis are met.

6.9.1.6.d The CORE OPERATING LIMITS REPORT, including any mid-cycle revisions or supplements thereto, shall be provided upon issuance, for each reload cycle, to the NRC Document Control Desk with copies to the Regional Administrator and Resident Inspector.

STEAM GENERATOR TUBE INSPECTION REPORT 6.9.1.7 A report shall be submitted within 180 days after the initial entry into MODE 4 following completion of an inspection performed in accordance with TS 6.8.4.g, Steam Generator (SG)

Program. The report shall include:

a. The scope of inspections performed on each SG,

b. Degradation mechanisms found,

c. Nondestructive examination techniques utilized for each degradation mechanism,

d. Location, orientation (if linear), and measured sizes (if available) of service induced indications,

e. Number of tubes plugged during the inspection outage for each degradation mechanism,

f. The number and percentage of tubes plugged to date and the effective plugging percentage in each steam generator.

MILLSTONE - UNIT 3 6-21 Amendment No. 24, 40, 50, 69, 104, 173, 212, 215, 229, 238, 245, 249. 252, 255, 256, 279

Serial No.23-126 Docket No. 50-423 Attachment 2, Page 5 of 5 INSERT A

27. ANP-10342-P-A, GAIA Fuel Assembly Mechanical Design, (Framatome Proprietary). Methodology for Specification:

3.2.2.1 Heat Flux Hot Channel Factor Note: Dominion Energy letter (Serial No.23-105) dated May 2, 2023 has requested NRC approval of the addition of new TS 6.9.1.6.b COLR references 24, 25, and 26. Therefore, this LAR is requesting the addition of new COLR reference 27. The numbering sequencing will be confirmed based on the sequence of Amendment issuance.

Serial No.23-126 Docket No. 50-423 Attachment 4 ANP-4040NP, REVISION 0, MILLSTONE UNIT 3 MECHANICAL DESIGN REPORT FOR GAIA FUEL TRANSITION, LICENSING REPORT (NON-PROPRIETARY)

Dominion Energy Nuclear Connecticut, Inc.

Millstone Power Station Unit 3

0414-12-F04 (Rev. 004, 04/27/2020)

All Rights Reserved FRAMATOME INC. TRADEMARKS AFA 3G, AREA, COBRA-FLX, COPERNIC, GAIA, GRIP, HMP, HTP, M5, M5Framatome, Mark-BW, MONOBLOC, ORFEO, and Q12 are trademarks or registered trademarks of Framatome or its affiliates, in the USA or other countries.

0414-12-F04 (Rev. 004, 04/27/2020)

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page i Nature of Changes Section(s)

Item or Page(s) Description and Justification 1 All Initial Issue

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page ii Contents Page 1.0 PURPOSE ......................................................................................................... 1-1 2.0 GAIA DESIGN DESCRIPTION .......................................................................... 2-1 2.1 Fuel Assembly Description ..................................................................... 2-2 2.2 Fuel Rod Description .............................................................................. 2-2 2.3 GAIA Spacer Grids ................................................................................. 2-4 2.4 Intermediate GAIA Mixer Grids ............................................................. 2-10 2.5 HMP End Spacer Grids......................................................................... 2-13 2.6 Top Nozzle............................................................................................ 2-17 2.7 GRIP Bottom Nozzle ............................................................................. 2-20 2.8 MONOBLOC Guide Tube and Instrument Tube ................................... 2-24 2.9 Materials ............................................................................................... 2-26 3.0 GAIA OPERATIONAL EXPERIENCE ............................................................... 3-1 3.1 Lead Test Assembly Experience ............................................................ 3-1 3.2 Reload Experience ................................................................................. 3-2 4.0 LICENSING BASES .......................................................................................... 4-1 4.1 Topical Report Reviews .......................................................................... 4-5 4.2 ANP-10342 Topical Report ..................................................................... 4-7 4.2.1 ANP-10342 Justification for Use .................................................. 4-7 4.2.2 ANP-10342 SER Restrictions ...................................................... 4-7 4.3 BAW-10227 (Revision 1) Topical Report ................................................ 4-9 4.3.1 BAW-10227 (Revision 1) Justification for Use ............................. 4-9 4.3.2 BAW-10227 (Revision 1) SER Restrictions .................................. 4-9 4.4 BAW-10231 Topical Report .................................................................... 4-9 4.4.1 BAW-10231 Justification for Use.................................................. 4-9 4.4.2 BAW-10231 SER Restrictions .................................................... 4-10 4.5 XN-75-32 Topical Report ...................................................................... 4-10 4.5.1 XN-75-32 Justification for Use.................................................... 4-10 4.5.2 XN-75-32 SER Restrictions ........................................................ 4-10 4.6 BAW-10227 (Revision 2) Topical Report .............................................. 4-11 4.6.1 BAW-10227 (Revision 2) Justification for Use ........................... 4-11 4.6.2 BAW-10227 (Revision 2) SER Restrictions ................................ 4-12 4.7 ANP-10334 Topical Report ................................................................... 4-13

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page iii 4.7.1 ANP-10334 Justification for Use ................................................ 4-13 4.7.2 ANP-10334 SER Restrictions .................................................... 4-13 4.8 BAW-10240 Topical Report .................................................................. 4-15 4.8.1 BAW-10240 Justification for Use................................................ 4-15 4.8.2 BAW-10240 SER Restrictions .................................................... 4-15 4.9 BAW-10183 Topical Report .................................................................. 4-17 4.9.1 BAW-10183 Justification for Use................................................ 4-17 4.9.2 BAW-10183 SER Restrictions .................................................... 4-17 4.10 ANP-10311 Topical Report ................................................................... 4-18 4.10.1 ANP-10311 Justification for Use ................................................ 4-18 4.10.2 ANP-10311 SER Restrictions .................................................... 4-18 4.10.3 ANP-10311 Changes ................................................................. 4-20 4.11 BAW-10084 Topical Report .................................................................. 4-20 4.11.1 BAW-10084 Justification for Use................................................ 4-20 4.11.2 BAW-10084 SER Restrictions .................................................... 4-21 4.12 ANP-10337 Topical Report ................................................................... 4-21 4.12.1 ANP-10337 Justification for Use ................................................ 4-21 4.12.2 ANP-10337 SER Restrictions .................................................... 4-21 4.13 ANP-10337, Supplement 1 Topical Report ........................................... 4-25 4.13.1 ANP-10337, Supplement 1 Justification for Use ........................ 4-25 4.13.2 ANP-10337, Supplement 1 SER Restrictions ............................ 4-25 5.0 DESIGN EVALUATIONS ................................................................................... 5-1 5.1 Mechanical Evaluations .......................................................................... 5-1 5.1.1 General Component Stress .......................................................... 5-1 5.1.2 General Component Fatigue ........................................................ 5-5 5.1.3 Fretting Wear ............................................................................... 5-6 5.1.4 Fuel Rod/Fuel Assembly Bow and Growth ................................... 5-7 5.1.5 Fuel Assembly Lift-Off .................................................................. 5-9 5.1.6 General Component Structural Deformation .............................. 5-10 5.1.7 Fuel Assembly Drop Accident .................................................... 5-20 5.2 Thermal Mechanical Evaluations .......................................................... 5-22 5.2.1 Cladding Stress Normal Operation and AOO ............................. 5-22 5.2.2 Cladding Buckling [ ] ................................................. 5-24 5.2.3 Cladding Structural Deformation (Faulted Stress) ...................... 5-25 5.2.4 Transient Cladding Strain ........................................................... 5-26 5.2.5 Cladding Fatigue ........................................................................ 5-27 5.2.6 Cladding Oxidation ..................................................................... 5-28 5.2.7 Fuel Rod Internal Pressure ........................................................ 5-29

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page iv 5.2.8 Internal Hydriding ....................................................................... 5-30 5.2.9 Cladding Creep Collapse ........................................................... 5-31 5.2.10 Overheating of Fuel Pellets (Centerline Fuel Melt)..................... 5-32 5.3 Thermal Hydraulic Evaluations ............................................................. 5-33 5.3.1 Fuel Rod Bow............................................................................. 5-33

6.0 CONCLUSION

S ................................................................................................ 6-1

7.0 REFERENCES

.................................................................................................. 7-1

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page v List of Tables Table 2-1 Materials Utilized on the GAIA Design .................................................... 2-26 Table 3-1 GAIA Operating Experience Summary ..................................................... 3-2 Table 4-1 Summary of Applicable Criteria and Topical Reports ............................... 4-2 Table 4-2 Summary of Analyses Associated with Topical Reports ........................... 4-6 Table 4-3 ANP-10342 Limitations and Conditions .................................................... 4-8 Table 4-4 BAW-10227 (Revision 1) Limitations and Conditions ............................... 4-9 Table 4-5 BAW-10231 Limitations and Conditions ................................................. 4-10 Table 4-6 XN-75-32 Limitations and Conditions ..................................................... 4-11 Table 4-7 BAW-10227 (Revision 2) Applicability .................................................... 4-12 Table 4-8 BAW-10227 (Revision 2) Limitations and Conditions ............................. 4-12 Table 4-9 ANP-10334 Limitations and Conditions .................................................. 4-14 Table 4-10 BAW-10240 Limitations and Conditions ................................................. 4-16 Table 4-11 BAW-10183 Limitations and Conditions ................................................. 4-17 Table 4-12 ANP-10311 Limitations and Conditions ................................................. 4-19 Table 4-13 BAW-10084 Limitations and Conditions ................................................. 4-21 Table 4-14 ANP-10337 Limitations and Conditions .................................................. 4-22 Table 4-15 ANP-10337, Supplement 1 Limitations and Conditions .......................... 4-26 Table 5-1 Normal Operation and AOO Component Stress Limiting Margins ............ 5-4 Table 5-2 Shipping and Handling Component Stress Limiting Margins .................... 5-5 Table 5-3 Faulted Component Stress Limiting Margins .......................................... 5-15

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page vi List of Figures Figure 2-1 Summary - GAIA Fuel Assembly at Millstone Unit 3 ............................. 2-1 Figure 2-2 Fuel Rod Assembly ................................................................................ 2-3 Figure 2-3 GAIA Spacer Grid .................................................................................. 2-6 Figure 2-4 GAIA Spacer Grid - Inner/Outer Strip Features..................................... 2-7 Figure 2-5 GAIA Spacer Grid - Spring Hull Features.............................................. 2-8 Figure 2-6 GAIA Spacer Grid Connection ............................................................... 2-9 Figure 2-7 IGM Grid .............................................................................................. 2-11 Figure 2-8 IGM Grid Features ............................................................................... 2-12 Figure 2-9 HMP End Spacer Grid ......................................................................... 2-14 Figure 2-10 HMP End Spacer Grid Features .......................................................... 2-15 Figure 2-11 HMP End Spacer Grid Connection ...................................................... 2-16 Figure 2-12 Top Nozzle........................................................................................... 2-18 Figure 2-13 Top Nozzle 1/4 Turn QD ...................................................................... 2-19 Figure 2-14 GRIP Bottom Nozzle ............................................................................ 2-21 Figure 2-15 GRIP Bottom Nozzle Filter ................................................................... 2-22 Figure 2-16 GRIP Bottom Nozzle Connection ......................................................... 2-23 Figure 2-17 MONOBLOC Guide Tube .................................................................... 2-25 Figure 5-1 [ ] ................................................................. 5-17

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page vii Nomenclature Acronym Definition AOO Anticipated Operational Occurrence ASME American Society of Mechanical Engineers ASTM American Society for Testing and Materials BOL Beginning of Life CFM Centerline Fuel Melt CHF Critical Heat Flux CUF Cumulative Usage Factor DGE Deformable Grid Element DNB(R) Departure from Nucleate Boiling (Ratio)

EOL End of Life FRGPC Fuel Rod Gas Pressure Criterion GAD Gadolinia GT Guide Tube GTRF Grid to Rod Fretting ID Inner Diameter IGM Intermediate GAIA Mixer IT Instrument Tube LAR License Amendment Request L&Cs Limitations and Conditions LHGR Linear Heat Generating Rate LOCA Loss of Coolant Accident LTA Lead Test Assembly NRC Nuclear Regulatory Commission OBE Operating Basis Earthquake PIE Post-Irradiation Examination PWR Pressurized Water Reactor QD Quick Disconnect RCCA Rod Cluster Control Assembly SAFDL Specified Acceptable Fuel Design Limit SER/TER Safety Evaluation Report / Technical Evaluation Report SFP Spent Fuel Pool SRP Standard Review Plan SSE Safe Shutdown Earthquake TCS Transient Cladding Strain TD Theoretical Density

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 1-1 1.0 PURPOSE The purpose of this document is to provide design-related inputs to Dominion in support of their Millstone Unit 3 License Amendment Request (LAR) for transition to the GAIA fuel design planned for cycle 24 in 2025. The design-related inputs include Mechanical, Thermal-Mechanical, and Thermal-Hydraulic.

Along with this Mechanical Design Report, separate Safety Summary Reports and an AREA Summary Report will be provided to Dominion to encompass the full work scope of the Framatome analyses in support of the fuel transition. The Safety Summary Reports will cover the LOCA events. The AREA Summary Report will cover the Chapter 15 rod ejection event.

This document is delineated as follows. Section 2.0 provides the GAIA fuel assembly design description. Section 3.0 provides an overview of GAIA operating experience gained by Framatome in Westinghouse 17x17 3-loop and 4-loop plants. Section 4.0 provides a summary of the Mechanical, Thermal-Mechanical, and Thermal-Hydraulic licensing bases. Section 5.0 provides the Mechanical, Thermal-Mechanical, and Thermal-Hydraulic design evaluations performed to show compliance with the governing Nuclear Regulatory Commission (NRC)-approved design criteria.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-1 2.0 GAIA DESIGN DESCRIPTION The GAIA fuel assembly design is generically approved by the NRC in Reference 1.

Figure 2-1 provides a summary of the GAIA fuel assembly design to be inserted at Millstone Unit 3, with component details provided in the subsequent sections.

Figure 2-1 Summary - GAIA Fuel Assembly at Millstone Unit 3

Standard Reconstitutable Top Nozzle 3-leaf Alloy 718 holddown system with 1/4-turn Quick Disconnect

Welded Cage

[ ]

24 - Q12 MONOBLOC Guide Tubes Increased cross-sectional area Low creep properties

1 - Q12 Instrument Tube Low creep properties

6 - M5 GAIA Spacer Grids 8-line fuel rod contact Trailing edge mixing vanes

3 - M5 Intermediate GAIA Mixer Grids Additional mixing for thermal performance Trailing edge mixing vanes

2 - Alloy 718 HMP End Spacer Grids Low-Force upper grid to mitigate fuel rod bow Positive grip force through end of life

GRIP Bottom Nozzle High filtering efficiency Stabilized outlet flow

264 Fuel Rods Advanced M5 Cladding

[ ] UO2 pellets Gadolinia (GAD) burnable poison pellets

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-2 2.1 Fuel Assembly Description The GAIA fuel assembly design at Millstone Unit 3 is consistent with the dimensional attributes in Ref. 1. It incorporates eleven (11) spacer grids, twenty-four (24) guide tubes (GTs), one (1) instrument tube (IT), and top and bottom nozzles to provide the structural cage for 264 fuel rods. The eleven (11) spacer grids include six (6) GAIA structural grids axially distributed along the fuel assembly, three (3) Intermediate GAIA Mixer (IGM) grids placed between the GAIA structural grids in the top of the active fuel region, and two (2) HMP end spacer grids with one at the top and one at the bottom.

The fuel rods are slightly raised off the bottom nozzle and are laterally supported by the GAIA spacer grids and HMP end spacer grids.

Twenty-four (24) 1/4-turn Quick Disconnect (QD) mechanisms attach the top nozzle to the cage. The QD attachments welded to the top of each GT allow the top nozzle to be removed remotely under water without the generation of loose parts and without the need for replacement parts.

Twenty-four (24) cap screws attach the GRIP bottom nozzle to the cage. The self-capturing connections allow the bottom nozzle to be removed remotely under water without the generation of loose parts and without the need for replacement parts.

2.2 Fuel Rod Description The GAIA fuel rod design at Millstone Unit 3 includes M5 cladding, Zircaloy-4 end caps, UO2 and GAD pellets, blanket pellets, and a nickel alloy plenum spring. Rods are pressurized with helium to provide good heat transfer, reduce clad creep-down, and restrict pellet to cladding interaction. The design utilizes a 144 inch fuel stack length and a nominal 0.0065 inch diametric pellet to cladding clearance.

The cylindrically shaped pellets are sintered to a nominal theoretical density (TD) up to

[ ] and a diameter of 0.3225 inch. Dished ends and geometric edge features ease the pellet loading into the cladding to prevent chipping and reduce the tendency of the pellet to assume an hourglass shape during operation.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-3 The optimized chemical composition of the M5 alloy cladding and its refined microstructure provide enhanced resistance to corrosion and very low hydrogen uptake.

This translates to less embrittlement, greater reliability at higher burnups, and compliance with loss of coolant accident (LOCA) and reactivity initiated accident requirements.

The Zircaloy-4 upper and lower end caps have the same geometry. The bullet nose feature provides a smooth flow transition and facilitates rod insertion during fabrication.

End caps have a grippable top-hat shape that allows for removal from the fuel assembly in either direction. Upset-shape welds connect the end caps to the cladding.

The nickel alloy plenum spring is placed in the upper region, preventing the formation of fuel stack gaps during shipping and handling, and allowing fuel stack expansion during operation.

Figure 2-2 highlights the fuel rod design features.

Figure 2-2 Fuel Rod Assembly

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-4 2.3 GAIA Spacer Grids The GAIA fuel assembly design at Millstone Unit 3 incorporates six (6) GAIA structural grids, which are designed to combine Critical Heat Flux (CHF) performance, mechanical performance, and fretting resistance. Constructed from M5 strip material, the individual strips are slotted and assembled in an egg-crate configuration and welded at each grid strip intersection. The trailing edges of the inner strips are equipped with mixing vanes.

The outer strip precludes handling damage by incorporating a thicker strip, butt-welded corner joints inboard of the square envelope, and large lead-in tabs.

Spring hulls in spacer cells provide the interface with the fuel rods. They are inserted into the bottom of the grid and welded at the bottom strip intersections. [

] The spring hulls are oriented at 45 degrees to the strip, resulting in a spring in each cell corner that is vertically aligned with the fuel rod and emulates the 8-line contact area of Framatomes HTP design. It has been confirmed by comparative tests and post irradiation examination (PIE) that the fretting behavior of the GAIA spacer grid rod support is consistent with the HTP spacer grid. The magnitude of the grid restraining force on the fuel rod is set high enough to ensure sufficient fuel rod support without overstressing the cladding at the points of contact or inducing excessive axial load on the fuel rod.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-5 The GAIA spacer grid is connected to the twenty-four (24) GTs and one (1) IT by

[ ] on each tube. In addition to maintaining the spacer grid axial positions, the weld connections help increase the fuel assembly lateral stiffness [ ]

welds result in a high localized rotational stiffness and high overall cage lateral stiffness.

The high overall cage lateral stiffness allows the fuel assembly to resist twist and bow, particularly at high burnups when spacer grid relaxation significantly reduces the coupling between the fuel rod and structural cage.

The GAIA spacer grid geometry results in a favorable mechanical behavior during accident conditions by remaining stable after exceeding its elastic range. This is due to the spring hull, which provides localized reinforcement at each strip intersection. Under compressive dynamic loading, this stabilizing effect resists large plastic deformations and maintains load-carrying capability. Deformation of the spacer grid is uniformly distributed in each row as the [ ] With this compressive failure mode, geometric changes in the GT and fuel rod arrays remain relatively small.

Under severe external dynamic loads, the GAIA spacer grid supports safe shutdown by maintaining the coolable geometry limits and providing a path for control rod insertion.

The ability of the spacer grid to [ ] via uniformly distributed deformations, protects the core during severe postulated accident conditions.

Figure 2-3 through Figure 2-6 highlight the GAIA spacer grid design features.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-6 Figure 2-3 GAIA Spacer Grid

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-7 Figure 2-4 GAIA Spacer Grid - Inner/Outer Strip Features

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-8 Figure 2-5 GAIA Spacer Grid - Spring Hull Features

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-9 Figure 2-6 GAIA Spacer Grid Connection

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-10 2.4 Intermediate GAIA Mixer Grids The GAIA fuel assembly design at Millstone Unit 3 incorporates three (3) IGM grids, which are designed based on Framatomes Advanced Mark-BW Mid-Span Mixing Grid design. The IGM grids provide additional flow mixing in the high-heat flux region for improved Departure from Nucleate Boiling (DNB) margin. Constructed from M5 material, the individual strips are slotted and assembled in an egg-crate configuration and welded at each strip intersection. To minimize the effect on bundle pressure drop and to limit the additional material added within the active fuel region, the spacer grids are made from strips that are axially shorter than the GAIA spacer grids. The IGM has a smaller envelope than the adjacent GAIA spacer grids, which minimizes mechanical interaction with adjacent fuel assemblies.

Similar to the GAIA spacer grid, the trailing edges of the inner strips are equipped with mixing vanes to enhance mixing. The mixing vane pattern is consistent with the GAIA spacer grid.

Stops formed in each of the four (4) cell walls prevent the fuel rods from contacting the mixing vanes but impose no grip force (or slip load) onto the rods; thus, these are designated non-contacting spacer grids. The outer strip design precludes handling damage by incorporating a larger strip thickness (than the inner strips), wrap around corners which are inboard of the square envelope, and large leading and trailing edge lead-in tabs.

The IGM is connected to twenty-four (24) GTs and one (1) IT by resistance spot welding to four (4) weld tabs on the top side. In addition to maintaining the spacer grid axial positions, the welded connections increase the fuel assembly lateral stiffness.

Figure 2-7 and Figure 2-8 highlight the IGM grid design features.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-11 Figure 2-7 IGM Grid

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-12 Figure 2-8 IGM Grid Features

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-13 2.5 HMP End Spacer Grids The GAIA fuel assembly design at Millstone Unit 3 incorporates two (2) HMP end spacer grids. Constructed from precipitation-hardened nickel alloy 718, individual HMP doublet strips are slotted and assembled in an egg-crate configuration and welded at each strip intersection. Each doublet is made from two (2) individual singlet strips tack welded together, forming a straight flow channel through the center of two (2) opposing springs. The straight flow channel minimizes hydraulic resistance and is designed for locations outside the active fuel region where flow mixing is less important. The springs laterally preload and center the fuel rod within each cell and create the grid-to-rod fretting resistant 8-line interface. The outer strip design precludes handling damage by incorporating lap welded corners which are inboard of the square envelope, and large leading and trailing edge lead-in tabs.

The nickel alloy 718 material provides high strength and reduced cell irradiation relaxation. The reduced cell relaxation, in combination with the 8-line interface, ensures that the HMP end spacer grid provides fuel rod lateral support and significant resistance against fretting wear throughout the design life.

One (1) HMP end spacer grid is used at the bottom of the fuel assembly, a region of the core where cross flows can be higher. One (1) low-force HMP end spacer grid is used at the top of the fuel assembly. The low-force HMP end spacer grid has a reduced slip load compared to the bottom HMP end spacer grid, which is intended to reduce the fuel rod compressive forces due to axial fuel rod growth and mitigate fuel rod bow.

The HMP end spacer grids are axially restrained by spacer sleeves, which are resistance spot welded directly to the GTs and IT above and below the spacer grid.

Figure 2-9 through Figure 2-11 highlight the HMP end spacer grid design features.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-14 Figure 2-9 HMP End Spacer Grid

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-15 Figure 2-10 HMP End Spacer Grid Features

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-16 Figure 2-11 HMP End Spacer Grid Connection

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-17 2.6 Top Nozzle The GAIA fuel assembly design at Millstone Unit 3 incorporates Framatomes standard top nozzle design. The top nozzle consists of two (2) high strength stainless steel bi-block frames, welded together to form a box-like structure. The upper structure interfaces with the reactor internals and the core components. The lower structure and grillage flow-hole pattern is designed to balance low pressure drop and strength requirements.

Four (4) sets of leaf springs made of nickel alloy 718 are fastened to the nozzle with nickel alloy 718 clamp screws. During operation, the springs prevent fuel assembly lift from hydraulic forces which ensures positive interaction with the upper and lower core internals. The upper leaf has an extended tang that engages a cutout in the top plate of the nozzle. This arrangement ensures spring leaf retention in the unlikely event of a spring leaf or clamp screw failure.

The attachment of the top nozzle to the GT consists of a 1/4-turn QD assembly locking mechanism, which allows top nozzle removal and replacement. Removal and replacement requires only hand tools, generates no loose parts, and does not require any replacement hardware. This contributes to a significant reduction in the amount of time required to perform fuel repairs and inspections. The locking mechanism is designed to rotate 90° in either direction to lock or unlock, and provides a positive indication when rotation is complete.

Figure 2-12 and Figure 2-13 highlight the top nozzle design features.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-18 Figure 2-12 Top Nozzle

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-19 Figure 2-13 Top Nozzle 1/4 Turn QD

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-20 2.7 GRIP Bottom Nozzle The GAIA fuel assembly design at Millstone Unit 3 incorporates the GRIP bottom nozzle design, which combines high filter efficiency, high mechanical robustness, and low pressure drop characteristics, along with features for flow stabilization and protection against excessive rod vibration.

The GRIP bottom nozzle is made of three (3) basic components. A one-piece stainless steel machined frame with deep ribs provides the main structure. Four (4) stainless steel feet are welded to the frame and provide the interface features for the lower core internals. A high strength stainless steel filter plate is fastened on the bottom face of the frame to provide high filtering efficiency.

Counter-bores in the top surface of the frame, and a leading-edge transition feature in the middle of the frame, are designed to align with the fuel rod lower end caps. The fuel rod seats on the bottom of the counter-bore towards end of life, when the fuel assembly is most susceptible to grid-to-rod fretting (GTRF). The seated fuel rod in the counter-bore, in combination with the leading-edge transition feature, results in a streamlined flow through the nozzle, which minimizes the lower region turbulence. When the lower end cap is encapsulated within the counter-bore, it protects against excessive fuel rod vibration that could be caused by flow anomalies in the lower region.

The GRIP bottom nozzle lower connection incorporates a self-securing screw feature, allowing removal and replacement of the nozzle with no loose parts and no replacement hardware. The self-securing screws remain in the bottom nozzle during handling.

Figure 2-14 through Figure 2-16 highlight the GRIP bottom nozzle design features.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-21 Figure 2-14 GRIP Bottom Nozzle

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-22 Figure 2-15 GRIP Bottom Nozzle Filter

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-23 Figure 2-16 GRIP Bottom Nozzle Connection

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-24 2.8 MONOBLOC Guide Tube and Instrument Tube The GAIA fuel assembly design at Millstone Unit 3 incorporates twenty-four (24)

MONOBLOC GTs and an IT. The MONOBLOC GT outer diameter of [ ]

is constant over the entire length, which results in additional material thickness and structural reinforcement in the reduced inner diameter (ID) dashpot region. This provides additional resistance to twist and bow at high burnups when spacer grid relaxation significantly reduces the coupling between the fuel rod and structural cage.

Four (4) weep holes in the dashpot region allow coolant outflow during Rod Cluster Control Assembly (RCCA) insertion and coolant inflow to control components during normal operation.

The MONOBLOC GT is constructed of Framatomes Q12 quaternary alloy, which is approved for use as a structural material in Reference 2. Q12 is an evolutionary development based on Framatomes M5 metallurgy, with small amounts of tin and iron added. Tin improves resistance to creep, and its content is limited to prevent degradation of the corrosion kinetics. Iron, in combination with niobium, is a key element for ensuring good corrosion performance. For structural components, these modifications provide higher irradiation creep strength without compromising the corrosion resistance. Q12 is processed the same way as M5, resulting in a fully recrystallized microstructure with fine grains and uniformly distributed precipitates.

The Q12 IT has a uniform inner and outer diameter. It is centrally located within the 17x17 array, extends the length of the fuel, and is fixed to the cage by resistance welds.

Figure 2-17 highlights the MONOBLOC GT design features.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-25 Figure 2-17 MONOBLOC Guide Tube

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 2-26 2.9 Materials Table 2-1 summarizes the materials utilized on the GAIA design at Millstone Unit 3, identifying the alloys and corresponding components.

Table 2-1 Materials Utilized on the GAIA Design Material Component Fuel Rod Cladding M5 IGM Grids GAIA Structural Spacer Grids Quick Disconnect Sleeves Fuel Rod End Caps Zircaloy-4 Guide Tube End Fittings Spacer Capture Rings Guide Tubes Q12 Instrument Tube Top and Bottom Nozzle Structures Lower Connection Screws Stainless Steel Holddown Spring Lock Wire Bottom Nozzle Filter Plate, Fastening Pins, Washers HMP End Spacer Grids Lower Connection Locking Rings Nickel Alloy Holddown Leaf Springs, Spring Screws Quick Disconnect Locking Springs, Rings, Lugs Fuel Rod Plenum Springs UO2, and Gd2O3-UO2 Fuel pellets

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 3-1 3.0 GAIA OPERATIONAL EXPERIENCE GAIA lead test assembly (LTA) and reload operating experience is provided in this section. Table 3-1 provides a summary of the quantity of fuel assemblies in operation.

3.1 Lead Test Assembly Experience Four (4) GAIA LTAs were inserted in the core of a Westinghouse 3-loop international reactor in 2012. The LTAs successfully completed four (4) 12-month cycles of leaker-free performance, and two (2) assemblies successfully completed a fifth 12-month cycle with leaker-free performance.

Eight (8) GAIA LTAs were inserted in the core of a Westinghouse 3-loop domestic reactor in 2015. Four (4) of the LTAs successfully completed two (2) 18-month cycles, and the other four (4) completed a third 18-month cycle, with leaker-free performance.

Four (4) GAIA LTAs were inserted in the core of a Westinghouse 4-loop domestic reactor in 2019. The LTAs have completed two (2) 18-month cycles of leaker-free performance and are currently operating in their third cycle.

Four (4) GAIA LTAs were inserted in a Westinghouse 4-loop domestic reactor in 2021.

The LTAs completed one (1) short cycle (9 months) of leaker-free performance and will be re-inserted in a subsequent cycle.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 3-2 3.2 Reload Experience A total of three (3) reloads each have been delivered to two (2) Westinghouse 3-loop international reactors, starting in 2020. The initial reload has completed two (2) 12-month cycles of leaker-free operation.

A total of two (2) reloads have been delivered to a Westinghouse 3-loop domestic reactor, starting in 2021. The initial reload has completed one (1) 18-month cycle of leaker-free operation.

Table 3-1 GAIA Operating Experience Summary

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-1 4.0 LICENSING BASES The GAIA Mechanical Fuel Assembly Design topical report per Ref. 1 is the governing licensing document for the GAIA transition at Millstone Unit 3. The foundation of Ref. 1 is the establishment of NRC-approved Specified Acceptable Fuel Design Limits (SAFDLs) that address the Acceptance Criteria defined in the Standard Review Plan (SRP), Section 4.2, NUREG-0800 (Ref. 3) for each of the fuel damage mechanisms.

Only certain SAFDLs are established within Ref. 1, with others defined via reference to previously NRC-approved topical reports. In addition to Section 4.2, Acceptance Criteria from Sections 4.3 (Nuclear Design) and 4.4 (Thermal and Hydraulic Design) of NUREG-0800 were also considered. The guidance provided within the SRP ensures that the relevant NRC regulations (e.g. 10 CFR 50.46 and 10 CFR 50, Appendix A, General Design Criteria 10, 27 and 35) are met.

Table 4-1 provides a summary of the Acceptance Criteria sections from Ref. 1, and these are in general alignment with the analyses that are performed to justify acceptance to the SAFDLs. For each Acceptance Criteria and associated analysis, a list of applicable topical reports is provided which collectively are used to demonstrate compliance. The purpose of each topical report is included (e.g. criteria, method, material properties), and a cross reference to the Mechanical, Thermal-Mechanical, or Thermal-Hydraulic sections is provided where additional details associated with the criteria, method, and analyses are located. For those Acceptance Criteria sections that are not explicitly covered in this document (e.g. those associated with LOCA), a note is included indicating where that specific item will be addressed.

The licensing bases section is further delineated by assessing each of the topical reports listed in Table 4-1, including justification of applicability, changes from the content in Ref. 1 (e.g. an NRC-approved method replaced by another NRC-approved method), changes to any specific NRC-approved topical report content, and compliance with associated Safety Evaluation Report (SER) restrictions (i.e. Limitations and Conditions, (L&Cs)).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-2 Table 4-1 Summary of Applicable Criteria and Topical Reports Ref. 1 Applicable Topical Evaluation Criteria Description Topical Report Purpose Section Report Section 8.1 Fuel System Damage 8.1.1 Stress, Strain, Loading Limits ANP-10342 (Ref. 1) Criteria, Method 5.1.1 General Component Stress ANP-10334 (Ref. 2) Material Properties BAW-10227 (Ref. 4) Criteria, Material Properties 5.2.1 Cladding Stress ANP-10342 (Ref. 1) Method Cladding Buckling BAW-10227 (Ref. 4) Criteria, Method, Material Properties 5.2.2 ANP-10342 (Ref. 1) Criteria 5.2.4 Transient Cladding Strain BAW-10231 (Ref. 5) Method, Material Properties 8.1.2 Strain Fatigue General Component Criteria, Method 5.1.2 ANP-10342 (Ref. 1)

Fatigue ANP-10342 (Ref. 1) Criteria 5.2.5 BAW-10227 (Ref. 4) Method, Material Properties Cladding Fatigue Method, specifically to provide inputs to the BAW-10231 (Ref. 5) fatigue analysis.

8.1.3 Fretting Wear ANP-10342 (Ref. 1) Criteria, Method 5.1.3 Oxidation, Hydriding, and ANP-10342 (Ref. 1) Criteria 5.2.6 8.1.4 Crud BAW-10231 (Ref. 5) Method 8.1.5 Fuel Rod / Fuel Assembly Bow and Growth Method 5.3.1 Fuel Rod Bow XN-75-32 (Ref. 6)

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-3 Ref. 1 Applicable Topical Evaluation Criteria Description Topical Report Purpose Section Report Section Method, specifically the gap closure ratio BAW-10227 (Ref. 7) model ANP-10342 (Ref. 1) Criteria, Method 5.1.4.1 Method, specifically the fuel assembly Fuel Rod Growth ANP-10334 (Ref. 2) growth model Method, specifically the fuel rod growth BAW-10240 (Ref. 13) model ANP-10342 (Ref. 1) Criteria, Method 5.1.4.2 Fuel Assembly Growth Method, specifically the fuel assembly ANP-10334 (Ref. 2) growth model 8.1.6 Fuel Rod Internal Pressure ANP-10342 (Ref. 1) General Criteria 5.2.7 BAW-10183 (Ref. 8) Explicit Criteria Fuel Rod Internal Pressure BAW-10231 (Ref. 5) Method Extends the applicability of Ref. 8 to M5 BAW-10227 (Ref. 4) material.

DNB Propagation See Section 5.2.7.3 for further details.

ANP-10342 (Ref. 1) Criteria, Method 5.1.5 Method, specifically the fuel assembly 8.1.7 Fuel Assembly Lift-Off ANP-10334 (Ref. 2) growth model ANP-10311 (Ref. 9) Method, specifically to determine lift loads.

8.2 Fuel Rod Failure 8.2.1 Hydriding ANP-10342 (Ref. 1) Criteria, Method 5.2.8 ANP-10342 (Ref. 1) General Criteria 5.2.9 BAW-10084 (Ref 10) Explicit Criteria, Method 8.2.2 Cladding Collapse BAW-10231 (Ref. 5) Inputs for Ref. 10.

Extends the applicability of Ref. 10 to M5 BAW-10227 (Ref. 4) material

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-4 Ref. 1 Applicable Topical Evaluation Criteria Description Topical Report Purpose Section Report Section 8.2.3 Overheating of Fuel Pellets ANP-10342 (Ref. 1) Criteria 5.2.10 BAW-10231 (Ref. 5) Method 8.3 Fuel Coolability 8.3.1 General Component ANP-10337 (Ref. 11, 12) Criteria and Method 5.1.6 Structural Deformation Cladding Structural ANP-10337 (Ref. 11, 12) General Method, specific to generation of 5.2.3 Deformation loads BAW-10227 (Ref. 4) Explicit Criteria, Material Properties ANP-10342 (Ref. 1) Method 8.4 Additional Acceptance Criteria Overheating of cladding will be verified for relevant Chapter 15 events. This verification will be performed using an NRC-approved thermal-hydraulics code to evaluate the 8.4.1 Overheating of Cladding GAIA fuel design with the ORFEO-GAIA and ORFEO-NMGRID correlations against the approved acceptance criteria for departure from nucleate boiling.

8.4.2 Excessive Fuel Enthalpy Addressed in Framatomes AREA Summary Report (see Section 1.0).

8.4.3 Bursting Addressed in Framatomes Safety Summary Report (see Section 1.0).

8.4.4 Cladding Embrittlement Addressed in Framatomes Safety Summary Report (see Section 1.0).

8.4.5 Violent Expulsion of Fuel Addressed in Framatomes AREA Summary Report (see Section 1.0).

8.4.6 Fuel Rod Ballooning Addressed in Framatomes Safety Summary Report (see Section 1.0).

Section 8.4.7 of Ref. 1 lists explicit criteria that will be verified with an NRC-approved 8.4.7 Reactivity Coefficients method. Doppler coefficient shall be negative at all operating conditions, and power coefficient shall be negative at all operating power levels relative to hot zero power.

Supplemental Framatome Analyses N/A Fuel Assembly Drop N/A N/A 5.1.7 Accident

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-5 4.1 Topical Report Reviews Table 4-2 reconfigures the information from Table 4-1 to highlight the analyses that are associated with each topical report. Each topical report is then reviewed in detail in the subsequent sections, including justification of applicability and compliance with associated SER restrictions (i.e. L&Cs).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-6 Table 4-2 Summary of Analyses Associated with Topical Reports Topical Report Applicable Analyses General Component Stress General Component Fatigue Fretting Wear Fuel Rod Growth Fuel Assembly Growth Fuel Rod Internal Pressure Fuel Assembly Lift-Off Cladding Internal Hydriding ANP-10342 (Ref. 1)

Cladding Stress (Normal Operation, Faulted)

Cladding Fatigue Cladding Oxidation Transient Cladding Strain Overheating of Fuel Pellets Overheating of Cladding Reactivity Coefficients Cladding Stress Cladding Buckling Cladding Fatigue BAW-10227 (Ref. 4)

Fuel Rod Internal Pressure Cladding Collapse Cladding Structural Deformation Transient Cladding Strain Cladding Fatigue Oxidation, Hydriding, and Crud BAW-10231 (Ref. 5)

Fuel Rod Internal Pressure Cladding Collapse Overheating of Fuel Pellets XN-75-32 (Ref. 6) Fuel Rod Bow BAW-10227 (Ref. 7) Fuel Rod Bow General Component Stress ANP-10334 (Ref. 2) Fuel Rod and Assembly Growth Fuel Assembly Lift-Off BAW-10240 (Ref. 13) Fuel Rod and Assembly Growth BAW-10183 (Ref. 8) Fuel Rod Internal Pressure ANP-10311 (Ref. 9) Fuel Assembly Lift-Off BAW-10084 (Ref 10) Cladding Collapse ANP-10337 (Ref. 11, 12) General Component Structural Deformation Cladding Structural Deformation

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-7 4.2 ANP-10342 Topical Report 4.2.1 ANP-10342 Justification for Use The GAIA Mechanical Design topical report (ANP-10342, Ref. 1) defines the GAIA fuel design and addresses the Acceptance Criteria established in Section 4.2 of the Standard Review Plan (NUREG-0800, Ref. 3). ANP-10342 is explicitly NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

4.2.2 ANP-10342 SER Restrictions Per Section 4.0 of the SER for ANP-10342 (Ref. 1), there are a total of four (4) L&Cs.

Based on the following assessments in Table 4-3, all L&Cs are met for the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-8 Table 4-3 ANP-10342 Limitations and Conditions Limitation or Condition Method of Adherence

1. This GAIA fuel assembly design is approved The Millstone Unit 3 core designs will be for use with low enrichment uranium fuel, limited to low enrichment uranium fuel, which has been enriched to less than or equal which has been enriched to less than or to 5 percent. equal to 5 percent.

2. This GAIA fuel assembly design is licensed GAIA fuel assembly is designed to support for a maximum fuel rod burnup of 62,000 a peak UO2 rod burnup of 62 GWd/mtU.

Megawatt-days/metric ton of Uranium.

3. The final LTA program PIE report shall be GAIA LTA PIE report (Ref. 14) was submitted to NRC staff prior to any reload submitted to the NRC in July 2021.

batch GAIA assemblies reach the third cycle of operation.

4. As part of the plant-specific LAR The governing topical report for the implementing GAIA, the licensee must Millstone Unit 3 rod ejection accident is demonstrate acceptable performance of GAIA ANP-10338 (Ref. 15). Ref. 15 considers under RIA conditions, including fuel damage, the requirements of the most up-to-date coolable geometry, and radiological guidance and analytical limits per RG 1.236 consequences, using approved methods. (e.g., enthalpy rise within the fuel rod, Current guidance and analytical limits are centerline fuel temperature, rim fuel found in SRP 4.2 Appendix B. Newer guidance temperature, and departure from nucleate is expected soon (e.g., DG-1327). The boiling).

licensee should consider the most up-to-date guidance and analytical limits at the time of submittal. Alternative means to demonstrate compliance will be considered on a case-by-case basis.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-9 4.3 BAW-10227 (Revision 1) Topical Report 4.3.1 BAW-10227 (Revision 1) Justification for Use The M5 topical report (BAW-10227 Revision 1, Ref. 4) defines the M5 criteria, methods, and material properties, and is explicitly referenced in ANP-10342 (Ref. 1). By extension, the M5 topical report is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

4.3.2 BAW-10227 (Revision 1) SER Restrictions There is no explicit section for L&Cs within the SER for BAW-10227 Revision 1 (Ref. 4); however, per Section 4.0 of the SER there is one (1) L&C to consider. Based on the following assessment in Table 4-4, all L&Cs are met for the fuel transition at Millstone Unit 3.

Table 4-4 BAW-10227 (Revision 1) Limitations and Conditions Limitation or Condition Method of Adherence The GAIA fuel assembly is designed to The peak fuel rod burnup is limited to 62,000 support a peak UO2 rod burnup of 62 MWd/MTU.

GWd/mtU.

4.4 BAW-10231 Topical Report 4.4.1 BAW-10231 Justification for Use The COPERNIC topical report (BAW-10231, Ref. 5) defines the fuel rod computer code used to perform thermal-mechanical analyses and is explicitly referenced in ANP-10342 (Ref. 1). By extension, the COPERNIC topical report is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-10 4.4.2 BAW-10231 SER Restrictions There is no explicit section for L&Cs within the SER for BAW-10231 (Ref. 5); however, per Section 8.0 of the SER there is one (1) L&C to consider for the rod average burnup.

Based on the following assessment in Table 4-5, all L&Cs are met for the fuel transition at Millstone Unit 3.

Table 4-5 BAW-10231 Limitations and Conditions Limitation or Condition Method of Adherence Fuel licensing applications up to a rod average burnup GAIA fuel assembly is designed to of 62 Gwd/MTU. support a peak UO2 rod burnup of 62 GWd/mtU.

4.5 XN-75-32 Topical Report 4.5.1 XN-75-32 Justification for Use The Fuel Rod Bow topical report (XN-75-32, Ref. 6) defines the method for analyzing the effects of fuel rod bow, and is explicitly referenced in the GAIA Mechanical Design topical report ANP-10342 (Ref. 1). By extension, the Fuel Rod Bow topical report is NRC-approved for use with the GAIA fuel design in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

4.5.2 XN-75-32 SER Restrictions There is no explicit section for L&Cs within the NRC approval letter for XN-75-32 (Ref.

6). However, per the NRC approval letter, there is one (1) L&C to consider. Based on the following assessment in Table 4-6, all L&Cs are met for the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-11 Table 4-6 XN-75-32 Limitations and Conditions Limitation or Condition Method of Adherence The acceptance is not applicable to fuel Per Section 4.5.1, the Fuel Rod Bow designs which exhibit a greater propensity for topical report is NRC-approved for use with bowing than that given in data from which the the GAIA fuel design in all Westinghouse models reviewed were developed. 3-loop and 4-loop 17x17 reactors.

4.6 BAW-10227 (Revision 2) Topical Report 4.6.1 BAW-10227 (Revision 2) Justification for Use The latest version of the M5 topical report (BAW-10227 Revision 2, Ref. 7) provides updated information, data, and models relative to the original version (Ref. 4). Specific to the GAIA fuel transition at Millstone Unit 3, the gap closure model per Section 11.3 of BAW-10227 Revision 2 will replace that of Section 2.2.1 of the XN-75-32 (Ref. 6) TER for the fuel rod bow analysis.

Per Section 3.5.4 of the Ref. 7 SER, the new gap closure model is applicable to Westinghouse fuel designs that meet six (6) key characteristics. Based on the following assessments in Table 4-7, Ref. 7 is applicable to the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-12 Table 4-7 BAW-10227 (Revision 2) Applicability Key Characteristic Method of Adherence

1. [ The GAIA guide tube material is Q12, and the structural spacer grid material is

] M5Framatome.

2. [ ] The GAIA cladding material is M5Framatome.

3. [ ] The GAIA spacer grid spans are [ ]

inches.

4. [ The spacer grid to cladding contact design is GAIA.

]

5. [ ] The GAIA lower end spacer grid is alloy-718 material.

6. [ The GAIA upper end spacer grid is relaxed alloy-718 material.

]

4.6.2 BAW-10227 (Revision 2) SER Restrictions Per Section 4.0 of the SER for BAW-10227 Revision 2 (Ref. 7), there is a total of one (1) L&C. Based on the following assessment in Table 4-8, all L&Cs are met for the fuel transition at Millstone Unit 3.

Table 4-8 BAW-10227 (Revision 2) Limitations and Conditions Limitation or Condition Method of Adherence When applying the methodology described in GAIA fuel assembly is designed to BAW-10227P, Rev. 2, [ support a peak UO2 rod burnup of 62 GWd/mtU and peak GAD rod burnup of 55 GWd/mtU.

] licensees shall ensure that changes to expected fatigue cycles are appropriately captured in the fatigue evaluation.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-13 4.7 ANP-10334 Topical Report 4.7.1 ANP-10334 Justification for Use The Q12 topical report (ANP-10334, Ref. 2) defines the Q12 material properties, specifically the GT growth model, and is explicitly referenced in ANP-10342 (Ref. 1).

By extension, the Q12 topical report is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

4.7.2 ANP-10334 SER Restrictions Per Section 4.0 of the SER for ANP-10334 (Ref. 2), there are a total of four (4) L&Cs.

Based on the following assessments in Table 4-9, all L&Cs are met for the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-14 Table 4-9 ANP-10334 Limitations and Conditions Limitation or Condition Method of Adherence

1. AREVA must follow the model update This L&C is not applicable to the Millstone process as defined by the responses to RAIs 1 Unit 3 transition. The L&C is applicable to and 2, as described in Reference 4. design-specific Q12 growth models, and not the generic Q12 growth model. The generic Q12 GT growth model was used for the transition analyses.

2. AREVA must follow the surveillance program This L&C is not applicable to the Millstone as defined by the response to RAI3, as Unit 3 transition. Per the response to RAI3 described in Reference 5. The NRC further of ANP-10334 (Ref. 2), the surveillance imposes the condition that AREVA must program is specific to fuel designs that go complete the surveillance, and the associated to batch without an LTA program. Per comparison and validation of design limits, Section 3.0, the GAIA design has within one year of the discharge of these completed several LTA programs.

assemblies. This is to further ensure that data is collected prior to a large number of fuel assemblies reaching high exposure.

3. Burnup limits imposed on fuel and fuel GAIA fuel assembly is designed to support assembly designs will also apply to those a peak UO2 rod burnup of 62 GWd/mtU.

assemblies using Q12TM structural material.

4. Q12 is only approved for use in PWRs as a Q12 is used for the GAIA GT and IT.

structural material. This limits its use to guide tubes, spacer grids, and instrument tubes.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-15 4.8 BAW-10240 Topical Report 4.8.1 BAW-10240 Justification for Use The M5 Properties topical report (BAW-10240, Ref. 13) incorporates M5 material properties into several Framatome topical reports that were previously approved only for Zircaloy-4 material. Specific to the fuel transition at Millstone Unit 3, the M5 Properties topical report provides the fuel rod growth model and is explicitly referenced in ANP-10342 (Ref. 1). By extension, the M5 Properties topical report is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

4.8.2 BAW-10240 SER Restrictions Per Section 4.0 of the SER for BAW-10240 (Ref. 13), there are a total of four (4) L&Cs.

Based on the following assessments in Table 4-10, all L&Cs are met for the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-16 Table 4-10 BAW-10240 Limitations and Conditions Limitation or Condition Method of Adherence

1. The corrosion limit, as predicted by the best- This L&Cs is not applicable to the estimate model will remain below 100 microns Millstone Unit 3 transition. The L&Cs is for all locations of the fuel. specific to the Oxidation, Hydriding, and Crud SAFDL for which BAW-10240 is not the licensing basis. For the Millstone Unit 3 transition, BAW-10240 is only used to provide the M5 fuel rod growth model.

2. All of the conditions listed in the SEs for all This L&Cs is not applicable to the FANP methodologies used for M5 fuel analysis Millstone Unit 3 transition. For the will continue to be met, except that the use of Millstone Unit 3 transition, BAW-10240 is M5 cladding in addition to Zircaloy-4 cladding is only used to provide the M5 fuel rod growth now approved. model, and that growth model was explicitly established as part of BAW-10240. Therefore, the SEs associated with all the other methodologies that were incorporating M5 material properties are not relevant.

3. All FANP methodologies will be used only Per Section 6.1.7.1 of Ref. 13, a maximum within the range for which M5 data was fluence limit of 14x1021 n/cm2 is imposed.

acceptable and for which the verifications Per the governing fuel rod growth analysis discussed in BAW-10240(P) or Reference 2 for the fuel transition at Millstone Unit 3, was performed. the resulting fuel rod fluence value is bounded.

4. The burnup limit for this approval is 62 GAIA fuel assembly is designed to support GWd/MTU. a peak UO2 rod burnup of 62 GWd/mtU.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-17 4.9 BAW-10183 Topical Report 4.9.1 BAW-10183 Justification for Use The Fuel Rod Gas Pressure Criterion (FRGPC) topical report (BAW-10183, Ref. 8) defines the allowable steady-state fuel rod gas pressure criterion if it exceeds system pressure. BAW-10183 is referenced in Section 12.1.1 of the COPERNIC topical report (Ref. 5), which is explicitly referenced in ANP-10342. In addition, per Section 12.1.1 of the COPERNIC topical report, BAW-10183 is extended to M5 material via BAW-10227 Revision 1 (Ref. 4). Therefore, by extension, the FRGPC topical report is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors and is applicable to the fuel transition at Millstone Unit 3.

4.9.2 BAW-10183 SER Restrictions There is no explicit section for L&Cs within the SER for BAW-10183 (Ref. 8); however, per Section 3.0 of the SER there are two (2) L&Cs to consider. Based on the following assessments in Table 4-11, all L&Cs are met for the fuel transition at Millstone Unit 3.

Table 4-11 BAW-10183 Limitations and Conditions Limitation or Condition Method of Adherence

1. If LOCA LHGRs become limiting at Safety Summary Reports which cover the extended burnup levels for any BWFC design LOCA events are submitted to Dominion.

applications, the LOCA LHGR analyses should be submitted for NRC review.

2. If there are changes involving the power If DNB is predicted for any Chapter 15 peaking maps or other input parameters for the events, and Ref. 8 is used as the method response surface applications, the core for DNB propagation, the core protection protection analysis should be submitted for analysis will be submitted for review.

review.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-18 4.10 ANP-10311 Topical Report 4.10.1 ANP-10311 Justification for Use The COBRA-FLX topical report (ANP-10311, Ref. 9) defines a core thermal-hydraulic computer code. Specific to the GAIA fuel transition at Millstone Unit 3, COBRA-FLX is predominantly used to generate thermal-hydraulic lift loads in support of down-stream analysis, [

] Per Section 5.0 of the SER for ANP-10311, the code is suitable for stand-alone application to nuclear core thermal-hydraulic analyses for steady-state and transient conditions. Therefore, the COBRA-FLX topical report is applicable to the fuel transition at Millstone Unit 3.

4.10.2 ANP-10311 SER Restrictions Per Section 4.0 of the SER for ANP-10311 (Ref. 9), there are a total of two (2) L&Cs.

Based on the following assessments in Table 4-12, all L&Cs are met for the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-19 Table 4-12 ANP-10311 Limitations and Conditions Limitation or Condition Method of Adherence

1. The fuel rod model in COBRA-FLX and the The use of the COBRA-FLX internal rewetting model for post-CHF heat transfer will not fuel rod model is excluded. The use be used for safety-related analysis and are explicitly of the rewetting model is excluded.

excluded from this review. Additional limitations are The applicable limitations are specified for the empirical correlations that will be addressed. Note that per Ref. 9, in a used in licensing calculations. These empirical letter dated October 18, 2017, the correlations are listed in Table1-2 and Appendix A NRC approved the use of the standard of the TR (Reference 1) and are summarized as the friction factor correlation as part of following: their response to an Errata; therefore, a) water properties (IAPWS-IF97) the standard friction factor correlation b) friction factor correlation constants is also acceptable for use.

i. Lehman friction factor (with or without Szablewski correction) ii. wall viscosity correction option c) two-phase friction multiplier - homogeneous model only d) bulk void correlation - Chexal-Lellouche (using the full curve fit routine or tables with interpolation) e) subcooled void correlation - Saha-Zuber f) subcooled boiling profile fit correlation - Zuber-Staub g) nucleate boiling force convection heat transfer correlation - Chen h) post-DNB forced convection heat transfer correlation - Groeneveld 5.7 i) single-phase convection heat transfer correlations

i. Sieder-Tate for normal flow conditions ii. McAdams natural convection correlation for very low flow conditions

2. This review examined only the specific models This L&C is covered by L&C #1.

and correlations requested by the applicant, as summarized in Section 2.0 of this SE. These are the only models and correlations that may be used in licensing calculations with the COBRA-FLX subchannel code. The fuel rod model in COBRA-FLX and the rewetting model for post-CHF heat transfer shall not be used for safety related analysis, and are specifically excluded from this review.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-20 4.10.3 ANP-10311 Changes 4.11 BAW-10084 Topical Report 4.11.1 BAW-10084 Justification for Use The CROV topical report (BAW-10084, Ref. 10) defines the fuel rod creep criteria and methodology for thermal-mechanical analyses, and is explicitly referenced in ANP-10342 (Ref. 1). In addition, CROV is extended to M5 material via BAW-10227 Revision 1 (Ref. 4). By extension, CROV is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-21 4.11.2 BAW-10084 SER Restrictions There is no explicit section for L&Cs within the TER for BAW-10084, Ref 10; however, per Section 5.0 of the TER there is one (1) L&C to consider. Based on the following assessment in Table 4-13, all L&Cs are met for the fuel transition at Millstone Unit 3.

Table 4-13 BAW-10084 Limitations and Conditions Limitation or Condition Method of Adherence The cladding temperature limit shall be less The Millstone Unit 3 creep collapse than or equal to 7000F (for the strain rate analysis maintained cladding temperatures equation to be applicable). that were compliant with the licensing limit.

4.12 ANP-10337 Topical Report 4.12.1 ANP-10337 Justification for Use The Faulted topical report (ANP-10337, Ref. 11) defines the criteria and method for analyzing the fuel assembly structural response to externally applied dynamic excitations (i.e. seismic and LOCA), and is explicitly referenced in ANP-10342 (Ref. 1).

By extension, it is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors; therefore, it is applicable to the fuel transition at Millstone Unit 3.

4.12.2 ANP-10337 SER Restrictions Per Section 5.0 of the SER for ANP-10337 (Ref. 11), there are a total of nine (9) L&Cs.

Based on the following assessments in Table 4-14, all L&Cs are met for the fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-22 Table 4-14 ANP-10337 Limitations and Conditions Limitation or Condition Method of Adherence

1. Dynamic grid crush tests, must be conducted in accordance Item a is met for the IGM.

with Section 6.1.2.1 of ANP-10337P (as amended by RAI 16), The IGM impact load limit and spacer grid behavior must satisfy the requirements in the corresponds to an ultimate, TR, the key elements of which are: or buckling, limit therefore items b and c do not

[ apply.

Per Section 4.13.2, this L&C is not applicable for the GAIA grid.

]

2. For fuel assembly designs where spacer grid applied loads The IGM load limit is based are limited based on allowable grid permanent deformation (as on buckling and not an opposed to buckling), the following limits from Table 4-1 of the allowable grid permanent TR apply: deformation; therefore, this

a. For all OBE analyses, allowable spacer grid deformation is L&C is not applicable.

limited to design tolerances and [

The allowable GAIA grid

] deformation limits for an

b. For SSE, LOCA, and combined SSE+LOCA analyses, Operating Basis

[ Earthquake (OBE) have been defined in accordance with item a.

] Per Section 4.13.2, item b is not applicable for the GAIA grid.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-23 Limitation or Condition Method of Adherence

3. The modification or use of the codes CASAC and ANSYS The CASAC code version (or other similar industry standard codes) are subject to the used is fully consistent with following limitations: the requirements of a and

a. CASAC computer code revisions, necessitated by errors b.

discovered in the source code, needed to return the algorithms to those described in ANP-10337P (as updated by RAIs) are The ANSYS code version acceptable. conforms to Framatome

b. Changes to CASAC numerical methods to improve code quality assurance convergence or speed of convergence, transfer of the code to procedures.

a different computing platform to facilitate utilization, addition of features that support effective code input/output, and changes to details below the level described in ANP-10337P would not be considered to constitute a departure from a method of evaluation in the safety analysis. Such changes may be used in licensing calculations without NRC staff review and approval. However, all code changes must be documented in an auditable manner to meet the quality assurance requirements of 10 CFR Part 50, Appendix B.

c. ANSYS or other industry standard codes may be used if they are documented in an auditable manner to meet the quality assurance requirements of 10 CFR Part 50, Appendix B, including the appropriate verification and validation for the intended application of the code.

4. This methodology is limited to applications that are similar The Millstone Unit 3 reactor to the current operating fleet of PWR reactor and fuel designs. is part of the current fleet The core geometry should be comparable to the current fleet, of PWR reactors in place at in terms of dimensions, dimension tolerances, fuel assembly the time of approval of row lengths, and the gaps between fuel assemblies. Fuel ANP-10337. ANP-10337 is designs should be comparable to the current fleet, in terms of applicable to the GAIA fuel materials, geometry, and dynamic behavior. design per Section 4.12.1.

5. ANP-10337P established generic fixed damping values The damping values per intended to be used for all PWR designs. All applications of ANP-10337 are applicable this methodology to new fuel assembly designs must consider to the GAIA fuel design per the continued applicability of the fixed damping values of this Section 4.12.1.

methodology. If new materials, new geometry, or new design features of a new fuel assembly design may affect damping, additional testing and/or evaluation to determine appropriate damping values may be required.

6. The ANP-10337P methodology includes the generation of GAIA fuel rod performance fuel rod loads, but does not provide a means to demonstrate under faulted conditions compliance for fuel rod performance under externally applied was demonstrated per loads (to applicable acceptance criteria). Applications of this Section 5.2.3.

methodology must provide an acceptable demonstration of fuel rod performance.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-24 Limitation or Condition Method of Adherence

7. As indicated in ANP-10337P when orthogonal deflections The more limiting from separate core locations are artificially superimposed to component stress calculate component stresses, the component stresses must allowables associated with be compared against the design criteria associated with rodded locations were control rod positions. used.

8. In accordance with RG 1.92, the combination of loads for The analysis performed is non-grid component evaluation should ideally be based on in accordance with RG 1.92 three orthogonal components (two horizontal and one vertical). and combines loads based

[ on three-orthogonal components.

]

9. [ A linear viscoelastic grid impact model is used for the IGM grid. The model

] limits the impact force to the buckling strength, [

]

Per Section 4.13.2, this L&C is not applicable for the GAIA grid.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-25 4.13 ANP-10337, Supplement 1 Topical Report 4.13.1 ANP-10337, Supplement 1 Justification for Use The Deformable Grid Element (DGE) topical report (ANP-10337 Supplement, Ref. 12) defines the criteria and method for analyzing a spacer grid that deforms significantly before failing. Specific to the GAIA fuel transition at Millstone Unit 3, the DGE topical report is limited to the GAIA structural grids (i.e., not the IGM grids) since the IGM grids do not have this deformation characteristic. Per Section 1.0 of the SER for the DGE topical report, the methodology is intended for use with the base methodology (Ref. 11) which is explicitly referenced in ANP-10342. Therefore, by extension, the DGE topical report is NRC-approved for use in all Westinghouse 3-loop and 4-loop 17x17 reactors and is applicable to the fuel transition at Millstone Unit 3.

4.13.2 ANP-10337, Supplement 1 SER Restrictions Per Section 5.0 of the SER for ANP-10337 Supplement 1 (Ref. 12), there are a total of two (2) L&Cs. These L&Cs are used in conjunction with those of the base methodology per Table 4-14, with the exception of L&Cs #1, #2b, and #9 which are only applicable to the linear viscoelastic elements. Based on the following assessments of the two (2) additional L&Cs in Table 4-15, all L&Cs are met for fuel transition at Millstone Unit 3.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 4-26 Table 4-15 ANP-10337, Supplement 1 Limitations and Conditions Limitation or Condition Method of Adherence

1. The residual deformation limit must be equal to or less than The allowable GAIA grid the smaller of the following two values: (1) the maximum deformation limits have residual deformation observed during the tests to determine been defined in accordance the input parameters for the DGE model, or (2) the with requirements 1 and 2.

deformation limits defined in ANP-10337P-A, that is, [

]

2. The applicability of the DGE model is limited to grids M5 material is used for the comprised of M5© alloy, Q12TM alloy, or materials that maintain GAIA grids, which are the an irradiated ductility (measured as percent total elongation) only components to use the that equals or exceeds M5© alloy. DGE model.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-1 5.0 DESIGN EVALUATIONS This section summarizes the Mechanical, Thermal-Mechanical, and Thermal-Hydraulic evaluations performed for the GAIA fuel design intended for batch implementation at Millstone Unit 3, including the transition from mixed-core configurations to full-core GAIA.

Each of the Mechanical, Thermal-Mechanical, and Thermal-Hydraulic sections include a description of the criteria (SAFDLs), methods, and results associated with each of the analyses completed to prevent fuel system damage for all known damage mechanisms.

As summarized in Table 4-1, the analyses are required by the governing NRC-approved topical reports.

The results provided are intended to demonstrate that GAIAs application at Millstone Unit 3 is capable of satisfying the NRC-approved design limits. Using NRC-approved analytical methods, future reload demonstrations of compliance to these design limits may exhibit more or less margin; as such, the NRC staffs approval should not be predicated on the margins provided.

5.1 Mechanical Evaluations This section summarizes the Mechanical analyses associated with the GAIA fuel design intended for batch implementation at Millstone Unit 3. All the Mechanical design criteria are met up to the licensed peak UO2 fuel rod burnup of 62 GWd/MTU and peak GAD fuel rod burnup of 55 GWd/MTU.

5.1.1 General Component Stress These calculations evaluate the structural integrity of the fuel assembly components under normal operation, anticipated operational occurrences (AOO), shipping, and handling loading conditions.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-2 5.1.1.1 Normal Operation and AOO Component Stress 5.1.1.1.1 Normal Operation and AOO Component Stress Criteria Licensing criterion for the normal operation and AOO component stress fuel damage mechanism is per Section 8.1.1.1 of the GAIA Mechanical Design topical report (Ref. 1).

Stresses and/or loads associated with normal operation, AOO, shipping, and handling shall be less than limits based on Section III of the ASME Code (Ref. 16) for all components, unless otherwise specified.

For qualifications by stress analysis the maximum stresses and loads on the components and component structural connections must remain below the specified minimum strength, critical buckling stresses, and/or below the stress levels defined in ASME Code Subsection NG for Level A service conditions.

The stress analysis criterion for Level A service from ASME Section III, Division 1, NG-3220, Fig. NG-3221-1, are used as follows:

Primary membrane stress intensity, Pm < Sm

Primary membrane plus bending stress intensity, Pm + Pb < 1.5 Sm

Primary and secondary membrane plus bending stress range, Pm + Pb + Q < 3Sm For qualifications by prototype test loading to ultimate load limits, the normal operating limit is generally determined by factoring the lower bound of the ultimate load limit, LU, by 0.44 for Level A service limits in accordance with Subsection NG-3228.4.

For qualifications by prototype test loading that establish plastic collapse load limits, the normal operating limit is generally determined by factoring the lower bound of the collapse load limit, LC, by 2/3 for Level A service limits in accordance with Subsection NG-3228.2.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-3 5.1.1.1.2 Normal Operation and AOO Component Stress Method The licensed method associated with the normal operation and AOO component stress analysis is per Section 8.1.1.2 of the GAIA Mechanical Design topical report (Ref. 1).

Conventional open-literature equations are used, in addition to general purpose finite element stress analysis codes, to calculate component stresses and/or loads associated with normal operation and AOOs. Loads due to differential thermal expansion between fuel rods and GTs, fuel assembly weight, holddown spring force, and RCCA impacts are included.

GT normal operating loads and stresses are evaluated on an individual span basis. GT stresses evaluated include primary membrane, primary membrane + bending, primary +

secondary, and buckling.

The maximum applied loads due to normal operation on the grid-to-GT and QD Upper Sleeve-to-QD Lower Sleeve weld joints are evaluated against the minimum specified strength or ASME load limits based on prototypical component tests. Top and Bottom Nozzle strengths are evaluated considering the maximum operating load and the allowable ASME load limit based on prototypical component tests.

5.1.1.1.3 Normal Operation and AOO Component Stress Results The limiting margins for the normal operation and AOO component stresses are summarized in Table 5-1.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-4 Table 5-1 Normal Operation and AOO Component Stress Limiting Margins 5.1.1.2 Shipping and Handling Component Stress 5.1.1.2.1 Shipping and Handling Component Stress Criteria Licensing criterion for the shipping and handling component stress fuel damage mechanism is per Section 8.1.1.1 of the GAIA Mechanical Design topical report (Ref. 1).

Stresses and/or loads associated with normal operation, AOO, shipping, and handling shall be less than limits based on Section III of the ASME Code (Ref. 16) for all components, unless otherwise specified.

Detailed criteria are similar to those defined in Section 5.1.1.1.1.

5.1.1.2.2 Shipping and Handling Component Stress Method The licensed method associated with the shipping and handling component stress analysis is per Section 8.1.1.2 of the GAIA Mechanical Design topical report (Ref. 1).

All axial loads for shipping and handling are evaluated for beginning of life (BOL) conditions and consider tension and compression. Shipping conditions are evaluated based on the maximum MAP-12 shipping container temperatures for normal conditions of transport. Applicable shipping and handling load limits for GAIA fuel include:

6g Lateral Acceleration

4g Maximum Axial Acceleration

2.5g Axial Handling

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-5 5.1.1.2.3 Shipping and Handling Component Stress Results The limiting margins for the shipping and handling component stresses are summarized in Table 5-2.

Table 5-2 Shipping and Handling Component Stress Limiting Margins 5.1.2 General Component Fatigue 5.1.2.1 General Component Fatigue Criteria Licensing criterion for the general component fatigue fuel damage mechanism is per Section 8.1.2.1 of the GAIA Mechanical Design topical report (Ref. 1).

For all components other than fuel rod cladding, the cumulative usage factor (CUF) shall be less than 1.0.

5.1.2.2 General Component Fatigue Method The licensed method associated with the general component fatigue analysis is per Section 8.1.2.2 of the GAIA Mechanical Design topical report (Ref. 1).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-6 The general methods prescribed in the ASME Code (Ref. 16) are used to evaluate component fatigue stresses. Due to the significant load bearing function of the GTs, in conjunction with their relatively thin-walled construction, GT fatigue is considered the most limiting and bounds all other components of the fuel assembly with the exception of the holddown springs.

GT fatigue usage is determined from the sum of the individual fatigue usage factors for each of the applicable recurring cyclic stress events. The fatigue usage for each stress cycle category is determined as the ratio of the applied number of stress cycles over the allowed number of stress cycles. The ODonnell-Langer curve for Zirconium material is used to estimate the corresponding number of allowed cycles of stress for each cyclic stress category and the associated alternating stress.

Evaluation of holddown spring fatigue is performed by combining the usage factors based on normal operation and upset condition reactor coolant system design transients. The alternating stress is calculated by multiplying the strain range by [

] in the ASME Code,Section III, NG-3228.

5.1.2.3 General Component Fatigue Results The criterion of a CUF less than 1 has been met, with a GT CUF of [ ] and a holddown spring CUF of [ ]

5.1.3 Fretting Wear 5.1.3.1 Fretting Wear Criteria Licensing criterion for the GTRF fuel damage mechanism is per Section 8.1.3.1 of the GAIA Mechanical Design topical report (Ref. 1).

Fuel rod failures due to fretting shall not occur.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-7 5.1.3.2 Fretting Wear Method The licensed method associated with the GTRF analysis is per Section 8.1.3.2 of the GAIA Mechanical Design topical report (Ref. 1).

Validation of the GAIA fuel rod fretting wear performance was based on the 1000-hour endurance flow testing in Framatomes HERMES-P and PHTF loops. Due to the first of a kind nature of the GAIA fuel assembly design, two (2) additional tests were conducted to supplement the 1000-hour testing. The PETER loop tests were used to evaluate self-induced excitation and flow-induced vibration characteristics. AUTOCLAVE tests were used to validate grid fretting wear characteristics. Furthermore, the GAIA LFA operating experience, in addition to relevant HTP design platform operating experience, demonstrates the GTRF performance for the GAIA design.

5.1.3.3 Fretting Wear Results Based on the endurance and fretting test results and operating experience, the relevant bounding reactor conditions and design parameters for Millstone Unit 3 have been verified in order to preclude GAIA GTRF failures.

5.1.4 Fuel Rod/Fuel Assembly Bow and Growth 5.1.4.1 Fuel Rod Growth 5.1.4.1.1 Fuel Rod Growth Criteria Licensing criterion for the fuel rod growth fuel damage mechanism is per Section 8.1.5.1 of the GAIA Mechanical Design topical report (Ref. 1).

Fuel rod irradiation growth is addressed by requiring clearance between the fuel rod and nozzles at end of life (EOL).

5.1.4.1.2 Fuel Rod Growth Method The licensed method associated with the fuel rod growth analysis is per Section 8.1.5.2 of the GAIA Mechanical Design topical report (Ref. 1).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-8 To assess fuel rod growth, empirical models are used to compute the irradiation growth of the fuel rod and fuel assembly and the resulting changes are compared with the specified dimensions. The upper bound fuel rod growth and lower bound fuel assembly growth are used in conjunction with component manufacturing tolerances to determine the clearance between the fuel rods and nozzles, also referred to as the fuel rod shoulder gap margin. The NRC-approved M5 fuel rod growth model per Ref. 13 is used for the fuel rod growth bounds. The NRC-approved Q12 GT growth model per Ref. 2 is used for the fuel assembly growth bounds.

5.1.4.1.3 Fuel Rod Growth Results The criterion of maintaining a positive fuel rod shoulder gap throughout life has been met with a margin of [ ]

5.1.4.2 Fuel Assembly Growth 5.1.4.2.1 Fuel Assembly Growth Criteria Licensing criterion for the fuel assembly growth fuel damage mechanism is per Section 8.1.5.1 of the GAIA Mechanical Design topical report (Ref. 1).

Fuel assembly irradiation growth is addressed by requiring clearance between the fuel assembly and reactor core plates at EOL.

5.1.4.2.2 Fuel Assembly Growth Method The licensed method associated with the fuel assembly growth analysis is per Section 8.1.5.2 of the GAIA Mechanical Design topical report (Ref. 1).

To assess fuel assembly growth, an empirical model is used to compute the irradiation growth of the fuel assembly and the resulting changes are compared with the specified dimensions of the core plate. The upper bound fuel assembly growth is used in conjunction with component and core plate manufacturing tolerances to determine the margin to top nozzle solid contact with the upper core plate. The NRC-approved Q12 GT growth model per Ref. 2 is used for the fuel assembly growth design limits.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-9 5.1.4.2.3 Fuel Assembly Growth Results The criterion of maintaining clearance between the fuel assembly and reactor core plates throughout life has been met with a margin of [ ]

5.1.5 Fuel Assembly Lift-Off 5.1.5.1 Fuel Assembly Lift-Off Criteria Licensing criterion for the fuel assembly lift-off fuel damage mechanism is per Section 8.1.7.1 of the GAIA Mechanical Design topical report (Ref. 1).

During normal operation conditions and AOO (with the exception of a pump over-speed transient), the holddown springs shall maintain fuel assembly contact with the lower support plate. Assuming a pump over-speed transient, fuel assembly lift-off can occur but the fuel assembly top and bottom nozzles shall maintain engagement with reactor internal pins and the holddown springs shall maintain positive holddown margin after the event.

5.1.5.2 Fuel Assembly Lift-Off Method The licensed method associated with the fuel assembly lift-off analysis is per Section 8.1.7.2 of the GAIA Mechanical Design topical report (Ref. 1).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-10 The fuel assembly lift-off methodology makes use of conventional open-literature equations to obtain a balance of forces on the fuel assembly in the vertical direction.

The forces are due to fluid friction loss, buoyancy, momentum change, holddown spring force, and gravity. Forces due to friction losses are obtained through the use of loss coefficients derived from flow testing. Holddown forces are obtained from testing. Fuel assembly dry weight is calculated. Other forces due to momentum and buoyancy are calculated based on the applicable fluid conditions. The evaluation includes the assessment of bounding operating conditions (including coolant temperatures and flowrates, mixed and homogeneous cores, BOL and EOL conditions), component dimensional characteristics (including reactor core plate to core plate and fuel assembly lengths, holddown spring deflections and mechanical set), and material characteristics (including thermal expansion, irradiation growth and relaxation, spring rate). The Q12 GT growth model in Ref. 2 is used to determine the fuel assembly growth bounds.

Uncertainties are accounted for using a combination of deterministic and statistical methods.

5.1.5.3 Fuel Assembly Lift-Off Results The criteria for fuel assembly lift-off have been met. The holddown springs maintain fuel assembly contact with the lower support plate for normal operation conditions.

During the pump over-speed transient, the fuel assembly top and bottom nozzles maintain engagement with reactor internal pins and the holddown springs maintain positive holddown margin after the event.

5.1.6 General Component Structural Deformation 5.1.6.1 General Component Structural Deformation Criteria Licensing criteria for the general component structural deformation fuel damage mechanism are per Section 4 of the Faulted topical report (Ref. 11). Specific to the GAIA spacer grid, additional criteria per Section 3.2 of the DGE topical report (Ref. 12) are applicable.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-11 Per Section 4 of Ref. 11, OBE stress and load limits are set at the level A limits defined in the ASME Code, unless otherwise specified. Safe Shutdown Earthquake (SSE) and LOCA stress and load limits are set at the Level D limits defined in the ASME Code, unless otherwise specified.

Due to their special functions (i.e. forming a path for control rod insertion, ensuring coolable geometry is maintained), IGM grids and GTs are subject to more stringent service limits including:

OBE Spacer Grid Acceptance Criteria:

IGM grid deformation experienced during an OBE event should not exceed the magnitude of the tolerance band to which the grid was designed. This acceptance criterion is established in the form of a grid impact load limit, which corresponds to a small amount of plastic deformation in the spacer grid that is within the envelope tolerance and does not exceed the deformation at the buckling point of the grid.

SSE/LOCA Spacer Grid Acceptance Criteria:

IGM grid deformation experienced during an SSE/LOCA event [

]

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-12

SSE/LOCA Guide Tube Acceptance Criteria:

Sudden and severe changes in the geometry of the GT (e.g. local collapse or plastic hinge) shall not occur. This acceptance criterion is further delineated by requiring that (1) stresses do not exceed a limit prohibiting local collapse of the GT, and (2) the structural stability of the GT must be maintained. The first criterion is met by limiting GT stresses to the Level C criteria in accordance with the ASME Code. The second criterion is satisfied by evaluating the critical buckling load margin.

Specific to the GAIA structural grid, per Section 3.2 of Ref. 12 the acceptance criteria per Section 4 of Ref. 11 are applicable with the following exceptions:

The limiting impact load is replaced with the limiting residual deformation. [

]

[

]

5.1.6.2 General Component Structural Deformation Method The licensed method associated with the general component structural deformation analysis is per Sections 7 and 8 of the Faulted topical report (Ref. 11) and Sections 4 and 5 of the Deformable Grid Element topical report (Ref. 12).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-13 Per Ref. 11, the faulted analysis is performed independently in the horizontal and vertical directions using numerical models developed to simulate the mechanical behavior of the fuel assemblies. The structural models are benchmarked to tests performed on prototypical fuel assemblies and components. The tests performed on the full fuel assemblies provide the main dynamic characteristics of the GAIA fuel assembly. The tests on spacer grids and other components provide both dynamic and strength characteristics that are used in both model definition and margin calculation.

These models capture the motion of the fuel due to the event and the interaction between neighboring fuel assemblies and the baffle as applicable.

Results from the horizontal and vertical analyses are used to calculate the maximum design impact loads and stresses which are then compared against the allowable values for each structural component.

An important issue addressed in the Ref. 11 methodology and reflected in the Millstone Unit 3 GAIA fuel assessment is the treatment of the NRC Information Notice IN-2012-09 (Ref. 18). IN-2012-09 requires accounting of both the direct effects of irradiation on spacer grid dynamic characteristics and strength and the indirect effects of spacer grid relaxation on fuel assembly dynamic characteristics.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-14 5.1.6.2.1 Deformable Grid Element Ref. 12 defines the methodology for introducing a nonlinear, deformable, spacer grid impact element into the base methodology detailed in Ref. 11. The horizontal analysis is updated to include the nonlinear response of the spacer grid through a DGE rather than a linear visco-elastic spring. The procedure to define the numerical models which represent the dynamic response of the fuel assembly is altered only by the inclusion of the nonlinear grid element. The numerical models capture the motion of the fuel assembly and the interaction between neighboring fuel assemblies as well as between the fuel assembly and the core baffle. The primary outputs from the horizontal analysis are the spacer grid deformations due to spacer grid impacts, and the deflections experienced by the fuel assemblies. The vertical analysis is not affected by this methodology.

5.1.6.2.2 Seismic and LOCA Time History Generation The faulted analysis involves the solving of non-linear equations of motion of the core row models under imposed displacement, velocity, and acceleration boundary conditions at the interfaces between the fuel assemblies and the reactor internals (lower core plate, upper core plate, and baffle plate elevations corresponding to the fuel assembly grid elevations).

The Seismic, LOCA, and LOCA hydraulic force time histories are derived from the raw data provided by customer transmittals. The transmittals contained the following motions: Accumulator Line Break, Pressurizer Surge Line break, Residual Heat Removal Line Break, Operation Basis Earthquake, Safe Shutdown Earthquake.

Perturbations of the seismic time histories are created for vertical and lateral sensitivity analyses per Ref. 3. Three (3) sensitivity histories are prepared for each seismic (OBE and SSE) history by modifying the nominal acceleration data as follows:

Increasing the motion amplitude by 10% - multiply acceleration by 1.1

Decreasing the motion frequency by 10% - divide sample time by 0.9

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-15

Increasing the motion frequency 10% - divide sample time by 1.1 Correct application of the sensitivity modifications is verified by comparing the response spectra of the seismic nominal and sensitivity time histories. The spectra are shifted in frequency and amplitude, relative to the nominal spectrum, as specified in the above list.

5.1.6.3 General Component Structural Deformation Results 5.1.6.3.1 General Component Results The limiting margins for the faulted condition are summarized in Table 5-3, for all components with the exception of grids.

Table 5-3 Faulted Component Stress Limiting Margins 5.1.6.3.2 Spacer Grid Results

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-16

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-17 Figure 5-1

[ ]

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-18 5.1.6.3.2.1 [ ]

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-19

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-20 5.1.7 Fuel Assembly Drop Accident As defined in Table 4-1, the fuel assembly drop accident is a supplemental analysis completed to ensure the number of failed fuel rods assumed in the fuel handling accident analysis of record remains bounding. This analysis is not explicitly associated with a SAFDL included in Ref. 1.

5.1.7.1 Fuel Assembly Drop Accident Criteria The estimated number of failed GAIA fuel rods due to a fuel handling accident must be bounded by the number of failed fuel rods allowed in the FSAR basis.

There are three (3) fuel handling accident cases summarized in the Millstone Unit 3 FSAR: i) fuel handling accident in the fuel building spent fuel pool (SFP)- (§15.7.4.2.1);

ii) fuel handling accident in containment (§15.7.4.2.2); and iii) fuel handling accident involving the drop of an insert component in the SFP (drop of RCCA -

§15.7.4.2.3). Based on these fuel handling accident descriptions, the number of failed rods allowed for each scenario are as follows;

Scenario #1, the fuel handling accident in the SFP can have 283 total failed fuel rods.

Scenario #2, the fuel handling accident in containment can have 283 total failed fuel rods.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-21

Scenario #3, the fuel handling accident with an insert in the SFP can have 30 total failed fuel rods.

5.1.7.2 Fuel Assembly Drop Accident Method Three (3) fuel assembly handling accidents were analyzed:

Scenario #1: Based on the description of the accident scenario in Section 15.7.4.2.1 of the Millstone Unit 3 FSAR, a GAIA fuel assembly is dropped onto another GAIA fuel assembly that is seated (vertical) in the SFP racks or refueling cavity (containment), whichever is bounding. The weight of the RCCA is included in the analysis.

Scenario #2: A Westinghouse fuel assembly is dropped onto a GAIA fuel assembly that is seated (vertical) in the SFP racks or refueling cavity (containment), whichever is bounding. The weight of the RCCA is included in the analysis.

Scenario #3: The RCCA component (including the weight of the handling tool) is dropped onto a seated GAIA fuel assembly (vertical) from a 2.7 ft drop height.

5.1.7.3 Fuel Assembly Drop Accident Results In all handling accident scenarios, the estimated failed fuel rods are bounded by the number of failed rods defined in Section 5.1.7.1.

Scenario #1: For the case where a GAIA fuel assembly is dropped on another GAIA fuel assembly, a total of [ ] failed fuel rods are predicted in the SFP accident and [ ] failed fuel rods are predicted in the containment accident, both below the criterion of 283.

Scenario #2: For the case where a Westinghouse fuel assembly is dropped on a GAIA fuel assembly, a total of [ ] failed fuel rods are predicted in the SFP accident and [ ] failed fuel rods are predicted in the containment accident, both below the criterion of 283.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-22

Scenario #3: For the case where a RCCA is dropped on a GAIA fuel assembly, a total of [ ] failed fuel rods are predicted, below the criterion of 30.

5.2 Thermal Mechanical Evaluations This section summarizes the Thermal-Mechanical analyses associated with the GAIA fuel design intended for batch implementation at Millstone Unit 3. All the Thermal-Mechanical design criteria are met up to the licensed peak UO2 fuel rod burnup of 62 GWd/MTU and peak GAD fuel rod burnup of 55 GWd/MTU.

Fuel rod Thermal-Mechanical evaluations are dependent on the rod power and core operating parameters, and therefore require verification on a cycle-specific basis to ensure the actual cycle design will not result in SAFDL non-compliance. All fuel rod analyses are based on inputs which either represent or bound operation at Millstone Unit 3.

5.2.1 Cladding Stress Normal Operation and AOO 5.2.1.1 Cladding Stress Normal Operation and AOO Criteria Licensing criteria for the normal operation and AOO cladding stress fuel damage mechanism are per the M5 topical report (Ref. 4, Section 3.3).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-23 5.2.1.2 Cladding Stress Normal Operation and AOO Method The licensed method associated with the fuel rod cladding stress normal operation and AOO analysis is per Section 8.1.1.2 of the GAIA Mechanical Design topical report (Ref. 1), with material properties per the M5 topical report (Ref. 4) used as input.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-24 5.2.1.3 Cladding Stress Normal Operation and AOO Results The criteria for normal operation and AOO cladding stress have been met, with a limiting margin of [ ]

5.2.2 Cladding Buckling [ ]

5.2.2.1 Cladding Buckling Criteria [ ]

Licensing criterion for the cladding buckling [ ] fuel damage mechanism is per the M5 topical report (Ref. 4, Section 3.3).

[ ]

5.2.2.2 Cladding Buckling Method [ ]

The licensed method associated with the cladding buckling [ ] analysis is per the M5 topical report (Ref. 4, Section 3.3), including material properties used as input.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-25 5.2.2.3 Cladding Buckling Results [ ]

The criterion for cladding buckling [ ] has been met, with a limiting margin of [ ]

5.2.3 Cladding Structural Deformation (Faulted Stress) 5.2.3.1 Cladding Structural Deformation (Faulted Stress) Criteria The general licensing criterion for the faulted cladding stress fuel damage mechanism is per the Faulted topical report (Ref. 11).

Fuel rods must be protected against mechanical fracturing.

Explicit criteria for the faulted cladding stress fuel damage mechanism are per the M5 topical report (Ref. 4, Section 3.3), as directed by Section 8.3.1.1 of Ref. 1.

M5 fuel rod cladding stress criteria are in accordance with those defined in Section 5.2.1.1.

5.2.3.2 Cladding Structural Deformation (Faulted Stress) Method The licensed method associated with generating the loads from the faulted conditions (i.e. SSE, LOCA) is per Sections 7 and 8 of the Faulted topical report (Ref. 11) and Sections 4 and 5 of the DGE topical report (Ref. 12). The licensed method for calculating the overall faulted stresses and margins is consistent with Section 8.1.1.2 of the GAIA Mechanical Design topical report (Ref. 1), with material properties per the M5 topical report (Ref. 4) used as input.

The faulted stress analysis is an extension of the normal operation cladding stress analysis per Section 5.2.1.2. As such, the cladding dimensional characteristics, cladding material properties, and other input parameters remain applicable.

Additionally, the values for normal operation stress intensities are used in the combined fuel rod normal operation and faulted condition stress calculation.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-26 Fuel rod cladding stresses in the faulted condition are the result of steady-state stresses from normal operation and vertical excitation-induced loads, bundle deflection-induced loads, and lateral impact-induced loads resulting from SSE and LOCA events. The OBE event is not explicitly analyzed as this event is bounded by the SSE and LOCA events. The fuel rod faulted condition stresses are load dependent (based on external forces) and are not self-limiting; therefore, the faulted condition stresses introduced in this analysis are classified as primary stresses and are combined with the normal operation sources of stress.

5.2.3.3 Cladding Structural Deformation (Faulted Stress) Results The criteria for faulted cladding stress have been met, with a limiting margin of [

] respectively for BOL and EOL. Fuel rod mechanical fracturing does not occur and the strength of the M5 cladding is not exceeded under faulted condition loads.

5.2.4 Transient Cladding Strain 5.2.4.1 Transient Cladding Strain Criteria Licensing criterion for the transient cladding strain (TCS) fuel damage mechanism is per Section 8.1.1.1 of the GAIA Mechanical Design topical report (Ref. 1).

Maximum uniform hoop strain (elastic plus plastic) shall not exceed 1%.

5.2.4.2 Transient Cladding Strain Method The licensed method associated with the TCS analysis is per the COPERNIC topical report (Ref. 5, Section 12.4).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-27 COPERNIC predicts the linear heat rates at which the cladding uniform hoop strain equals 1%. Cases are run with [

]

5.2.4.3 Transient Cladding Strain Results For the TCS fuel damage mechanism, linear heat rate limits have been predicted at which the cladding uniform hoop strain equals 1%. The TCS limits were provided to Dominion and need to be verified by Dominion on a cycle-specific basis.

5.2.5 Cladding Fatigue 5.2.5.1 Cladding Fatigue Criteria Licensing criterion for the cladding fatigue fuel damage mechanism is per Section 8.1.2.1 of the GAIA Mechanical Design topical report (Ref. 1).

For M5 fuel rod cladding, the CUF shall be less than 0.9.

5.2.5.2 Cladding Fatigue Method The licensed method associated with the cladding fatigue analysis is per the M5 topical report (Ref. 4, Section 3.6), including material properties used as input.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-28 Procedures for the fatigue analysis follow those outlined in the ASME Code. To determine the total fatigue usage factor of the cladding, all possible Condition I and II events are considered along with one Condition III event. Conservatisms include cladding thickness, oxide layer formation, and cladding pressure differential.

The fuel rod life is conservatively set to be eight (8) years, which bounds five (5) eighteen-month cycles of operation. With this, the fuel rod will experience 8/60 of the number of transients the reactor pressure vessel experiences in its sixty-year life.

The calculation uses the ODonnell Langer fatigue curve. Depending on which is the most conservative, the ODonnell Langer fatigue curve employs either a conservative factor of two (2) on the alternating stress intensity or an addition of twenty (20) on the number of cycles.

5.2.5.3 Cladding Fatigue Results The criterion for cladding fatigue has been met, with maximum calculated CUFs of

[ ] for UO2 and GAD rods, respectively, versus the design limit of 0.9.

5.2.6 Cladding Oxidation 5.2.6.1 Cladding Oxidation Criteria Licensing criterion for the cladding oxidation fuel damage mechanism is per Section 8.1.4.1 of the GAIA Mechanical Design topical report (Ref. 1).

Cladding peak oxide thickness shall not exceed a best-estimate predicted value of 100 microns.

5.2.6.2 Cladding Oxidation Method The licensed method associated with the cladding oxidation analysis is per the COPERNIC topical report (Ref. 5, Section 12.6).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-29 COPERNIC is used to predict a best-estimate cladding peak oxide thickness that occurs over the approved burnup range. It is applicable to both UO2 and GAD fuel types; however, GAD rods are not explicitly analyzed since the UO2 fuel rod power histories are heavier duty (higher power, temperature, and burnup) and therefore yield bounding oxide predictions. The analysis is based on nominal fuel rod characteristics and thermal hydraulic conditions. [ ]

5.2.6.3 Cladding Oxidation Results The criterion for cladding oxidation has been met, with a peak oxide thickness less than

[ ] versus the design limit of 100 microns.

5.2.7 Fuel Rod Internal Pressure 5.2.7.1 Fuel Rod Internal Pressure Criteria The general licensing criteria for the fuel rod internal pressure fuel damage mechanism are per Section 8.1.6.1 of the GAIA Mechanical Design topical report (Ref. 1).

Internal gas pressure of the peak fuel rod in the reactor will be limited to a value below that which would cause (1) the fuel-cladding gap to increase due to outward cladding creep during steady-state operation or (2) reorientation of the hydrides in the radial direction in the cladding.

Explicit criteria for the fuel rod internal pressure fuel damage mechanism are per the FRGPC topical report (Ref. 8). The M5 topical report (Ref. 4) extends the applicability of the FRGPC topical report to M5 material.

Pin pressure remains less than the reactor coolant system pressure [ ]

and that the ratio of clad to fuel strain rates always be less than [ ] (for rods over system pressure).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-30 5.2.7.2 Fuel Rod Internal Pressure Method The licensed method associated with the fuel rod internal pressure analysis is per the COPERNIC topical report (Ref. 5, Section 12.1).

Bounding steady-state internal gas pressures are determined from COPERNIC internal gas pressure predictions. The bounding pressure is composed of a COPERNIC best-estimate predicted pressure plus a pressure uncertainty allowance. The pressure uncertainty allowance is composed of a COPERNIC code uncertainty allowance and allowances due to fuel rod manufacturing variations. Steady-state power history envelopes are used in the analysis. Transient power history effects are captured through the inclusion of Condition I and II events over the projected life of the fuel rod.

5.2.7.3 Fuel Rod Internal Pressure Results The criteria for fuel rod internal pressure have been met. The limiting pin pressure of

[ ] psia is less than the design limit of [ ] psia. The clad to fuel strain rate limiting ratio of [ ] is less than the design limit of [ ]

NOTE:

According to Section 4.0 of Ref. 8, DNB propagation is precluded when internal pin pressure is below system pressure; however, if the internal pin pressure is above system pressure and DNB is predicted then an explicit DNB propagation analysis is required. If DNB is predicted for any Chapter 15 events then the NRC-approved methods per Ref. 8 or Ref. 17 may be used for evaluating DNB propagation.

5.2.8 Internal Hydriding 5.2.8.1 Internal Hydriding Criteria Licensing criterion for the internal hydriding fuel rod failure mechanism is per Section 8.2.1.1 of the GAIA Mechanical Design topical report (Ref. 1).

Internal hydriding shall be precluded by appropriate manufacturing controls.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-31 5.2.8.2 Internal Hydriding Method The licensed method associated with fuel rod internal hydriding is per Section 8.2.1.2 of the GAIA Mechanical Design topical report (Ref. 1).

Fuel rod internal hydriding is precluded by imposing tight controls on hydrogen impurities during fuel rod fabrication and on the fuel rod components, including careful moisture control of the fuel pellets.

5.2.8.3 Internal Hydriding Results GAIA UO2 and GAD fuel pellets have a total hydrogen content [

]

5.2.9 Cladding Creep Collapse 5.2.9.1 Cladding Creep Collapse Criteria The general licensing criteria for the cladding creep collapse fuel rod failure mechanism is per Section 8.2.2.1 of the GAIA Mechanical Design topical report (Ref. 1).

Predicted creep collapse life of the fuel rod must exceed the maximum expected in-core life.

Explicit criteria for the cladding creep collapse fuel rod failure mechanism are per the CROV topical report (Ref. 10). The M5 topical report (Ref. 4) extends the applicability of CROV to M5 material.

When the ovality creep rate of the cladding exceeds [ ] the cladding pressure differential exceeds the bifurcation buckling limit, or the generalized stress exceeds the generalized yield strength, the cladding is deemed failed.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-32 5.2.9.2 Cladding Creep Collapse Method The licensed method associated with the cladding creep collapse analysis is per the CROV topical report (Ref. 10), with inputs provided per the COPERNIC topical report (Ref. 5, Section 12.5). It is applicable to both UO2 and GAD fuel types; however, GAD rods are not explicitly analyzed since the UO2 fuel rod power histories are heavier duty (higher power, temperature, and burnup) and therefore yield bounding results.

COPERNIC is used to simulate the performance of the fuel rod throughout the rods lifetime. Output from COPERNIC is then used as input to initialize the CROV code.

The output parameters which CROV takes from the COPERNIC simulation are [

] The COPERNIC outputs along with the fuel rod geometry are then used by the CROV code in a simulation of the cladding creep-down deformations versus time of exposure of the fuel rod. The code checks the three (3) criteria at each time step.

[ ]

5.2.9.3 Cladding Creep Collapse Results The criteria for cladding creep collapse have been met.

5.2.10 Overheating of Fuel Pellets (Centerline Fuel Melt) 5.2.10.1 Centerline Fuel Melt Criteria Licensing criterion for the centerline fuel melt (CFM) fuel rod failure mechanism is per Section 8.2.3.1 of the GAIA Mechanical Design topical report (Ref. 1).

Fuel melting during normal operation and AOO is precluded.

5.2.10.2 Centerline Fuel Melt Method The licensed method associated with the CFM analysis is per the COPERNIC topical report (Ref. 5, Section 12.3).

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-33 COPERNIC predicts the linear heat rates at which the onset of fuel centerline melting occurs. Cases are run with [

]

5.2.10.3 Centerline Fuel Melt Results For the CFM fuel damage mechanism, linear heat rate limits have been predicted at which fuel melting is precluded. The CFM limits were provided to Dominion and need to be verified by Dominion on a cycle-specific basis.

5.3 Thermal Hydraulic Evaluations This section summarizes the Thermal-Hydraulic analyses associated with the GAIA fuel design intended for batch implementation at Millstone Unit 3. All the Thermal-Hydraulic design criteria are met up to the licensed peak UO2 fuel rod burnup of 62 GWd/MTU and peak GAD fuel rod burnup of 55 GWd/MTU.

5.3.1 Fuel Rod Bow 5.3.1.1 Fuel Rod Bow Criteria As documented in the Section 8.1.5.1 of the GAIA Mechanical topical report (Ref. 1),

there is no explicit design criterion for fuel rod bow. However, departure from nucleate boiling ratio (DNBR) and linear heat generating rate (LHGR) burnup thresholds and penalties are calculated and considered on a cycle-by-cycle basis.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-34 5.3.1.2 Fuel Rod Bow Method The licensed method associated with the fuel rod bow analysis is per the Fuel Rod Bow topical report (Ref. 6), with the exception of the model used to calculate the gap closure ratio as a function of fuel assembly burnup which is updated according to Ref. 7.

During irradiation, fuel rods will experience circumferentially unequal axial growth.

When this occurs, the gaps between the fuel rods will decrease as burnup increases.

The results from the analysis are augmentation factors to be used for power peaking (FQ) calculations and adjustment factors for minimum DNBR calculations.

Some flow channels will be reduced and the resulting change in local conditions can cause a decrease in the DNBR margin. The DNBR penalties are calculated considering the fractional closure, the hot rod average heat flux and the system pressure for the limiting anticipated transients. When determining the reduction in DNBR for gap closures greater than 50%, a change is made from Ref. 6 to the upper design limit gap closure ratio per Ref. 7. A practical effect of using the new correlation defined is the elimination of the dependence on geometric properties (i.e., rod diameters, rod pitch, and spacer pitch). The hot rod linear heat rate is still calculated using the rod outer diameter; however, even this is eliminated by using an event-specific value instead of the calculated value. A limiting hot rod linear heat rate and pressure are used. A set of penalty curves are calculated for burnups between [ ] Since the rod bow penalty between the threshold [ ] and the licensing burnup [ ] the slope and Y-intercept of each line are used to calculate the rod bow penalty for the hot rod linear heat rate for a given burnup.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 5-35 Local areas with excess water-to-uranium ratios can develop and can increase the local power peaking. The uncertainty associated with this local peaking will increase the uncertainty in FQ. The impact of rod bow on power peaking is evaluated by comparing the calculated uncertainty in FQ using a deterministic treatment with no rod bow to the uncertainty calculated by taking a root sum-of-the-squares of these uncertainties and the peaking effects of rod bow. If the uncertainty based on the root sum-of-the-squares is less than the deterministic value, no peaking penalty need be considered. When the uncertainty factor for peaking exceeds the target LHGR penalty, a LHGR penalty is imposed. The penalty on the LHGR is also calculated using the new gap closure correlation per Ref. 7 and the target LHGR.

5.3.1.3 Fuel Rod Bow Results The criterion for fuel rod bow has been met by calculating DNBR and LHGR burnup thresholds and penalties. The thresholds and penalties were provided to Dominion and need to be verified by Dominion on a cycle-specific basis.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 6-1

6.0 CONCLUSION

S The Framatome GAIA fuel design has been analyzed in accordance with NRC-approved Mechanical, Thermal-Mechanical, and Thermal-Hydraulic design criteria and methods using mixed core and full core cycle design inputs. All design criteria are met,

[ ] up to the licensed peak UO2 fuel rod burnup of 62 GWd/MTU and peak GAD fuel rod burnup of 55 GWd/MTU under normal and faulted operating conditions.

Framatome Inc. ANP-4040NP Revision 0 Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition Licensing Report Page 7-1

7.0 REFERENCES

1. ANP-10342P-A, Revision 0, GAIA Fuel Assembly Mechanical Design, September 2019.

2. ANP-10334P-A, Revision 0, Q12' Structural Material, September 2017

3. Standard Review Plan, Section 4.2, NUREG-0800 Revision 3, U.S. Nuclear Regulatory Commission, March 2007.

4. BAW-10227P-A, Revision 1, Evaluation of Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel, June 2003.

5. BAW-10231P-A, Revision 1, COPERNIC Fuel Rod Design Computer Code, January 2004.

6. XN-75-32P-A, Supplements 1, 2, 3, & 4, Computational Procedure for Evaluating Fuel Rod Bowing, October 1983.

7. BAW-10227P-A, Revision 2, Evaluation of Advanced Cladding and Structural Material (M5) in PWR Reactor Fuel, January 2023.

8. BAW-10183P-A, Revision 0, Fuel Rod Gas Pressure Criterion (FRGPC), July 1995.

9. ANP-10311P-A, Revision 1, COBRA-FLX: A Core Thermal-Hydraulic Analysis Code, October 2017.

10. BAW-10084P-A, Revision 3, Program To Determine In-Reactor Performance of BWFC Fuel Cladding Creep Collapse, July 1995.

11. ANP-10337P-A, Revision 0, PWR Fuel Assembly Structural Response to Externally Applied Dynamic Excitations, April 2018.

12. ANP-10337P-A, Revision 0, Supplement 1P-A, Revision 0, Deformable Spacer Grid Element, September 2020.

13. BAW-10240P-A, Revision 0, Incorporation of M5' Properties in Framatome ANP Approved Methods, May 2004.

14. ANP-3941P, Revision 0, GAIA Lead Test Assembly PIE Report, Technical Report, July 2021 (NRC Submittal Number ML21218A137, dated 7/30/2021, and ML21218A136).

15. ANP-10338P-A, Revision 0, AREA' - ARCADIA Rod Ejection Accident, December 2017.

16. American Society of Mechanical Engineers, Boiler and Pressure Vessel Code,Section III, Division 1, 2010, 2011a Addenda, 2013.

17. XN-NF-82-06(P)(A), Revision 1, & Supplements 2, 4, and 5, Qualification of Exxon Nuclear Fuel for Extended Burnup, October 1986.

18. NRC Information Notice 2012-09, Irradiation Effects on Fuel Assembly Spacer Grid Crush Strength - Available in the NRC ADAMS - accession number ML113470490.

Serial No.23-126 Docket No. 50-423 Attachment 5 FRAMATOME APPLICATION FOR WITHHOLDING AND AFFIDAVIT Dominion Energy Nuclear Connecticut, Inc.

Millstone Power Station Unit 3

AFFI DAVIT COMMONWEALTH OF VIRGINIA )

) ss.

CITY OF LYNCHBURG )

1. My name is Gayle Elliott. I am Director, Licensing & Regulatory Affairs, for Framatome Inc. (Framatome) and as such I am authorized to execute this Affidavit.

2. I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.

3. I am familiar with the Framatome information contained in licensing report ANP-4040P, Millstone Unit 3 Mechanical Design Report for GAIA Fuel Transition, and referred to herein as Document. Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.

4. This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.

5. This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is

requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.

6. The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:

(a) The information reveals details of Framatomes research and development plans and programs or their results.

(b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.

(c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.

(d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.

(e) The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.

The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(c), 6(d) and 6(e) above.

7. In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.

8. Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.

9. The foregoing statements are true and correct to the best of my knowledge, information, and belief.

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

Executed on: 4/12/2023

v t e Letter Sequence Other
EPID:L-2023-LLA-0074, (Approved, Closed)
Initiation Acceptance Administration Withholding Request Acceptance Questions 14 November 2023 Answers 21 December 2023 Results Approval Other: ML23145A195
MONTHYEAR2023-05-23 [Table View]

ML23145A195

Text

SUMMARY

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

6.0 CONCLUSION

7.0 REFERENCES

6.0 CONCLUSION

7.0 REFERENCES

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