Text

LLC Submittal of the Technical Report, Containment Vessel Ultimate Pressure Integrity, TR-121516, Revision 0
	ML23001A011
Person / Time
Site:	99902078, 05200050
Issue date:	12/31/2022
From:	Fosaaen C; NuScale
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML23001A010	List: ML23001A011;
References
	LO-133412
	Download: ML23001A011 (1)
	v • d • e

LO-133412 December 31, 2022 Docket No.52-050 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

SUBJECT:

NuScale Power, LLC Submittal of the technical report, Containment Vessel Ultimate Pressure Integrity, TR-121516, Revision 0

REFERENCES:

1. NuScale letter to NRC, NuScale Power, LLC Submittal of Planned Standard Design Approval Application Content, dated February 24, 2020 (ML20055E565)

2. NuScale letter to NRC, NuScale Power, LLC Requests the NRC staff to conduct a pre-application readiness assessment of the draft, NuScale Standard Design Approval Application (SDAA), dated May 25, 2022 (ML22145A460)

3. NRC letter to NuScale, Preapplication Readiness Assessment Report of the NuScale Power, LLC Standard Design Approval Draft Application, Office of Nuclear Reactor Regulation dated November 15, 2022 (ML22305A518)

4. NuScale letter to NRC, NuScale Power, LLC Staged Submittal of Planned Standard Design Approval Application, dated November 21, 2022 (ML22325A349)

NuScale Power, LLC (NuScale) is pleased to submit the technical report, Containment Vessel Ultimate Pressure Integrity, TR-121516, Revision 0. This report supports Chapter 3 of the Standard Design Approval Application, Design of Structures, Systems, Components and Equipment, Revision 0. Chapter 3 supports Part 2, Final Safety Analysis Report, (FSAR) of the NuScale Standard Design Approval Application (SDAA), as described in Reference 1. NuScale submits the report in accordance with requirements of 10 CFR 52 Subpart E, Standard Design Approvals. As described in Reference 4, the enclosure is part of a staged SDAA submittal. NuScale requests NRC review, approval, and granting of standard design approval for the US460 standard plant design.

From July 25, 2022 to October 26, 2022, the NRC performed a pre-application readiness assessment of available portions of the draft NuScale FSAR to determine the FSARs readiness for submittal and for subsequent review by NRC staff (References 2 and 3). The Containment Vessel Ultimate Pressure Integrity technical report was not available for NRC readiness assessment review.

Enclosure 1 contains the technical report, Containment Vessel Ultimate Pressure Integrity, TR-121516-P, Revision 0, proprietary version. NuScale requests that the proprietary version (Enclosure 1) be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390. The enclosed affidavit (Enclosure 3) supports this request. Enclosure 1 has also been determined to contain Export Controlled Information. This information must be NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

LO-133412 Page 2 of 2 12/31/2022 protected from disclosure per the requirement of 10 CFR § 810. Enclosure 2 contains the nonproprietary version.

This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.

If you have any questions, please contact Mark Shaver at 541-360-0630 or at mshaver@nuscalepower.com.

I declare under penalty of perjury that the foregoing is true and correct. Executed on December 31, 2022.

Sincerely, Carrie Fosaaen Senior Director, Regulatory Affairs NuScale Power, LLC Distribution: Brian Smith, NRC Michael Dudek, NRC Getachew Tesfaye, NRC Bruce Bavol, NRC David Drucker, NRC Enclosure 1: Containment Vessel Ultimate Pressure Integrity, TR-121516-P, Revision 0 (proprietary)

Enclosure 2: Containment Vessel Ultimate Pressure Integrity, TR-121516-NP, Revision 0 (nonproprietary)

Enclosure 3: Affidavit of Carrie Fosaaen AF-133413 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

LO-133412 : Containment Vessel Ultimate Pressure Integrity, TR-121516-P, Revision 0 (proprietary)

NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

LO-133412 : Containment Vessel Ultimate Pressure Integrity, TR-121516-NP, Revision 0 (nonproprietary)

NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Licensing Technical Report Containment Vessel Ultimate Pressure Integrity December 2022 Revision 0 Docket: 52-050 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 www.nuscalepower.com

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Licensing Technical Report COPYRIGHT NOTICE This report has been prepared by NuScale Power, LLC and bears a NuScale Power, LLC, copyright notice. No right to disclose, use, or copy any of the information in this report, other than by the U.S. Nuclear Regulatory Commission (NRC), is authorized without the express, written permission of NuScale Power, LLC.

The NRC is permitted to make the number of copies of the information contained in this report that is necessary for its internal use in connection with generic and plant-specific reviews and approvals, as well as the issuance, denial, amendment, transfer, renewal, modification, suspension, revocation, or violation of a license, permit, order, or regulation subject to the requirements of 10 CFR 2.390 regarding restrictions on public disclosure to the extent such information has been identified as proprietary by NuScale Power, LLC, copyright protection notwithstanding. Regarding nonproprietary versions of these reports, the NRC is permitted to make the number of copies necessary for public viewing in appropriate docket files in public document rooms in Washington, DC, and elsewhere as may be required by NRC regulations.

Copies made by the NRC must include this copyright notice and contain the proprietary marking if the original was identified as proprietary.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Licensing Technical Report Department of Energy Acknowledgement and Disclaimer This material is based upon work supported by the Department of Energy under Award Number DE-NE0008928.

This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights.

Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table of Contents Abstract . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 Executive Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.0 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.1 Purpose . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.2 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 1.3 Abbreviations and Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.0 Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1 Regulatory Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.1 CFR 50 Appendix A General Design Criterion 50 and 10 CFR 50.44 . . . . . . . . . 6 2.1.2 CFR 52.137 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.1.3 Regulatory Guide 1.216 - Containment Structural Integrity Evaluation for Internal Pressure Loading above Design Basis Pressure . . . . . . . . . . . . . . . . . . 7 2.1.4 NUREG/CR-6906 - Containment Integrity Research at Sandia National Laboratories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 3.0 Analysis of Containment Vessel for Ultimate Pressure Integrity . . . . . . . . . . . . . . . 9 3.1 Failure Criteria for Containment Vessel Ultimate Pressure Capacity. . . . . . . . . . . . . . . . 9 3.2 Methodology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 3.2.1 Failure Criteria and Ultimate Pressure Capacity . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2.2 Finite Element Analysis Model Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.2.3 Buckling of Containment Vessel Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 3.2.4 Tight Joint Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.3 Geometry and Material Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.3.1 Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.3.2 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 3.3.3 Material Properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 3.4 Three-Dimension Model Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 3.4.1 Modeling Simplification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 3.5 Finite Element Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.5.1 Mesh. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.5.2 Contact . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.6 Loads and Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 3.6.1 Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table of Contents 3.6.2 Boundary Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82 4.0 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90 4.1 Containment Vessel Pressure Capacity Based on Flange Gaps. . . . . . . . . . . . . . . . . . 90 4.2 Tight Joint Evaluation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 4.3 Strain Evaluation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101 4.4 Buckling of Upper and Lower Heads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110 4.4.1 Buckling of Containment Vessel Upper Head . . . . . . . . . . . . . . . . . . . . . . . . . 110 4.4.2 Buckling of Containment Vessel Lower Head . . . . . . . . . . . . . . . . . . . . . . . . . 113 5.0 Summary and Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117 6.0 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118 Appendix A Allowable O-Ring Springback Calculation. . . . . . . . . . . . . . . . . . . . . . . . . . .A-1 A.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-1 A.2 Methodology. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-2 A.3 Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .A-3 Appendix B Nonlinear Stress-Strain Curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1 B.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B-1 B.2 Nonlinear Stress-Strain Curves for ANSYS Material Property Input . . . . . . . . . . . . . .B-1

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 List of Tables Table 1-1 Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Table 1-2 Definitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Table 3-1 Materials. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 3-2 Material Properties at Design Temperature (600 Degrees Fahrenheit) . . . . . . . 16 Table 3-3 Steady-State Thermal Parameters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Table 3-4 Stud Preloads Applied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 Table 3-5 Seal Seating Loads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70 Table 3-6 Internal Pressures Applied - Containment Vessel Closure Flange Model . . . . . 73 Table 3-7 Internal Pressures Applied - Pressurizer Access Port, Manway Port, Control Rod Drive Mechanism Access Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 Table 3-8 Nozzle Blowoff Loads Applied in Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 Table 4-1 Pressure Capacity of Bolted Opening due to O-Ring Sealability . . . . . . . . . . . . 90 Table 4-2 Internal Pressure Required to Overcome Preload . . . . . . . . . . . . . . . . . . . . . . 100 Table A-1 Parameters Used in Allowable Springback Calculations for Each Seal . . . . . . .A-3 Table A-2 Allowable Springback Values for Each Seal . . . . . . . . . . . . . . . . . . . . . . . . . . .A-4 Table B-1 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 70 Degrees F . . . . . . . .B-1 Table B-2 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 140 Degrees F . . . . . . .B-2 Table B-3 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 500 Degrees F . . . . . . .B-3 Table B-4 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 600 Degrees F . . . . . . .B-4 Table B-5 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 70 Degrees F . . . . . . . . . .B-5 Table B-6 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 140 Degrees F . . . . . . . . .B-7 Table B-7 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 500 Degrees F . . . . . . . . .B-9 Table B-8 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 600 Degrees F . . . . . . . .B-11 Table B-9 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 70 Degrees F . . . . .B-13 Table B-10 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 140 Degrees F . . . .B-14 Table B-11 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 500 Degrees F . . . .B-15 Table B-12 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 600 Degrees F . . . .B-16 Table B-13 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 70 Degrees F . . . . . . . .B-17 Table B-14 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 140 Degrees F . . . . . . .B-18 Table B-15 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 650 Degrees F . . . . . . .B-20

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 List of Figures Figure 3-1 Three Dimensional Model Geometry - Containment Vessel Closure Flange and Strain Evaluation - Full View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Figure 3-2 Three Dimensional Model Geometry - Containment Vessel Closure Flange and Strain Evaluation - Closure Flange Close-up . . . . . . . . . . . . . . . . . . . . . . . 19 Figure 3-3 Three Dimensional Model Geometry - Containment Vessel Closure Flange and Strain Evaluation - Top View . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 Figure 3-4 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Full View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Figure 3-5 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Pressurizer Access Port Region . . . . . . . . . . . . . . . . 22 Figure 3-6 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Pressurizer Access Port Region Section View. . . . . . 23 Figure 3-7 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Pressurizer Access Port Region Section View Close-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Figure 3-8 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Full View. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Figure 3-9 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Manway Port Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Figure 3-10 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Manway Port Region Section View . . . . . . . . . . . . . . . . . . . . . . . . 27 Figure 3-11 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Manway Port Region Section View Close-up. . . . . . . . . . . . . . . . . 28 Figure 3-12 Three Dimensional Model Geometry - Containment Vessel Control Rod Drive Mechanism Access Port Evaluation - Full View . . . . . . . . . . . . . . . . . . . . 29 Figure 3-13 Three Dimensional Model Geometry - Containment Vessel Control Rod Drive Mechanism Access Port Evaluation - Control Rod Drive Mechanism Access Port Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Figure 3-14 Three Dimensional Model Geometry - Containment Vessel Control Rod Drive Mechanism Access Port Evaluation - Control Rod Drive Mechanism Access Port Region Close-up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Figure 3-15 Containment Vessel Closure Flange Finite Element Model Mesh - Full Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Figure 3-16 Containment Vessel Closure Flange Finite Element Model Mesh - Closure Flange Region and Mating Surface Details . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Figure 3-17 Containment Vessel Pressurizer Access Port Finite Element Model Mesh -

Full Model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Figure 3-18 Containment Vessel Pressurizer Access Port Finite Element Model Mesh -

Pressurizer Access Port Region. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 List of Figures Figure 3-19 Containment Vessel Pressurizer Access Port Finite Element Model Mesh -

Cross-Section Close-up View of Mating Surfaces Region . . . . . . . . . . . . . . . . . 38 Figure 3-20 Containment Vessel Manway Port Finite Element Model Mesh - Full Model. . . 39 Figure 3-21 Containment Vessel Manway Port Finite Element Model Mesh - Manway Port Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Figure 3-22 Containment Vessel Manway Port Finite Element Model Mesh - Cross-Section Close-up View of Mating Surfaces Region . . . . . . . . . . . . . . . . . . . . . . 41 Figure 3-23 Containment Vessel Control Rod Drive Mechanism Access Port Finite Element Model Mesh - Full Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Figure 3-24 Containment Vessel Control Rod Drive Mechanism Access Port Finite Element Model Mesh - Control Rod Drive Mechanism Access Port Region . . . 43 Figure 3-25 Containment Vessel Control Rod Drive Mechanism Access Port Finite Element Model Mesh - Cross-Section Close-up View of Mating Surfaces Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Figure 3-26 Containment Vessel Closure Flange Finite Element Analysis Model Contact Definition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Figure 3-27 Typical Contact Definition for Pressurizer Access Port, Manway, and Control Rod Drive Mechanism Access Closures . . . . . . . . . . . . . . . . . . . . . . . . 46 Figure 3-28 Convection Application for Containment Vessel Inside Diameter -

Containment Vessel Closure Flange Finite Element Analysis Model. . . . . . . . . 49 Figure 3-29 Convection Application for Containment Vessel Outside Diameter above Pool Level - Containment Vessel Closure Flange Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Figure 3-30 Convection Application for Containment Vessel Outside Diameter below Pool Level - Containment Vessel Closure Flange Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Figure 3-31 Convection Application for Containment Vessel Inside Diameter -

Pressurizer Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . 52 Figure 3-32 Convection Application for Containment Vessel Outside Diameter above Pool Level - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . 53 Figure 3-33 Convection Application for Containment Vessel Outside Diameter below Pool Level - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . 54 Figure 3-34 Convection Application for Containment Vessel Inside Diameter - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Figure 3-35 Convection Application for Containment Vessel Outside Diameter above Pool Level - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . 56 Figure 3-36 Convection Application for Containment Vessel Outside Diameter below Pool Level - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . 57

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 List of Figures Figure 3-37 Convection Application for Containment Vessel Internal Surfaces - Control Rod Drive Mechanism Access Port Finite Element Analysis Model. . . . . . . . . . 58 Figure 3-38 Convection Application for Containment Vessel External Surfaces - Control Rod Drive Mechanism Access Port Finite Element Analysis Model. . . . . . . . . . 59 Figure 3-39 Typical Application of Stud/Cover Surface-to-Surface Radiation . . . . . . . . . . . . 60 Figure 3-40 Application of Stud/Flange Surface-to-Surface Radiation for Closure Flange . . 61 Figure 3-41 Stud Preload Application - Containment Vessel Closure Flange Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Figure 3-42 Stud Preload Application - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64 Figure 3-43 Stud Preload Application - Body Selection - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 Figure 3-44 Stud Preload Application - Manway Port Finite Element Analysis Model . . . . . 66 Figure 3-45 Stud Preload Application - Body Selection - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Figure 3-46 Stud Preload Application - Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68 Figure 3-47 Stud Preload Application - Body Selection - Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . 69 Figure 3-48 Seal Seating Pressure Application Area - Typical Application . . . . . . . . . . . . . . 71 Figure 3-49 Internal Pressure Application Area - Containment Vessel Closure Flange Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 Figure 3-50 Internal Pressure Application Area - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Figure 3-51 Internal Pressure Application Area - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 Figure 3-52 Internal Pressure Application Area - Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 Figure 3-53 Applied Nozzle Blowoff Loads - External - Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80 Figure 3-54 Applied Nozzle Blowoff Loads - Internal - Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Figure 3-55 Frictionless Constraints - Symmetry Surfaces - Containment Vessel Closure Flange Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83 Figure 3-56 Frictionless Constraints - Symmetry Surfaces - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 Figure 3-57 Frictionless Constraints - Symmetry Surfaces - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 List of Figures Figure 3-58 Fixed Support - Support Skirt Bottom Surface - Containment Vessel Closure Flange Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . 86 Figure 3-59 Displacement Constraint - Bottom Surface - Pressurizer Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87 Figure 3-60 Displacement Constraint - Bottom Surface - Manway Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 Figure 3-61 Displacement Constraint - Bottom Surface - Control Rod Drive Mechanism Access Port Finite Element Analysis Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89 Figure 4-1 Contact Gap Plot - Manway Port Inner Mating Surface -

((2(a),(c),ECI psi Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Figure 4-2 Contact Gap Plot - Manway Port Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92 Figure 4-3 Contact Gap Plot - Pressurizer Access Port Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93 Figure 4-4 Contact Gap Plot - Pressurizer Access Port Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 Figure 4-5 Contact Gap Plot - Control Rod Drive Mechanism Access Port Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure . . . . . . . . . . . . . . . . . . . . . . 95 Figure 4-6 Contact Gap Plot - Control Rod Drive Mechanism Access Port Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure . . . . . . . . . . . . . . . . . . . . . . 96 Figure 4-7 Contact Gap Plot - Containment Vessel Closure Flange Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97 Figure 4-8 Contact Gap Plot - Containment Vessel Closure Flange Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 Figure 4-9 Location of 1.5 Percent Strain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 Figure 4-10 Location of Initial Yielding in the Shell away from Discontinuities . . . . . . . . . . 103 Figure 4-11 Location of Initial Yielding in the Control Rod Drive Mechanism Access Port Cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104 Figure 4-12 Location of Initial Yielding in the Control Rod Drive Mechanism Access Port Cover away from Stud Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105 Figure 4-13 Location of Initial Yielding in the Pressurizer Access Port Cover. . . . . . . . . . . 106 Figure 4-14 Location of Initial Yielding in the Pressurizer Access Port Cover away from Stud Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107 Figure 4-15 Location of Initial Yielding in the Manway Port Cover . . . . . . . . . . . . . . . . . . . 108 Figure 4-16 Location of Initial Yielding in the Manway Port Cover away from Stud Holes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Figure 4-17 Torispherical Head Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111 Figure 4-18 Torispherical Head Geometry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114 © Copyright 2022 by NuScale Power, LLC x

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 List of Figures Figure A-1 O-Ring Seal Springback Characteristic Curve . . . . . . . . . . . . . . . . . . . . . . . . . .A-2 © Copyright 2022 by NuScale Power, LLC xi

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Abstract This report describes the methodology used to develop the containment vessel (CNV) ultimate pressure integrity for the NuScale Power, LLC (NuScale) standard plant. The pressure determined within this report is for a beyond design basis event. The limiting ultimate pressure in this report is the minimum pressure the CNV can withstand before exceeding the elastic springback criteria of seals (resulting in the potential for the onset of leakage), loosening of joints, exceeding a plastic strain criterion, or the buckling of upper or lower heads. The associated pressures for all of these conditions are reported in this document. The ultimate pressure calculation follows the guidelines in Regulatory Guide (RG) 1.216, Revision 0 (Reference 1) and NUREG/CR-6906 (Reference 2). Material properties are from the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC), Section II material properties at design temperature. Nonlinear material curves are in accordance with ASME BPVC Section VIII, Division 2, Alternate Rules (Reference 9). © Copyright 2022 by NuScale Power, LLC 1

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Executive Summary The NRC regulations and guidance related to containment vessel (CNV) ultimate pressure integrity include 10 CFR 50.47, 10 CFR 50 Appendix A General Design Criterion (GDC) 50, and RG 1.216. Collectively, these regulations and regulatory guidance require an applicant to:

1. provide a level of design information sufficient to enable the NRC to evaluate the applicant's proposed means of assuring that construction conforms to the design and to reach a final conclusion on safety questions associated with the design before granting the standard design approval.

2. design the reactor containment structure, including access openings, penetrations, and the containment heat removal system so that the containment structure can accommodate, without exceeding the design leakage rate with sufficient margin, the calculated pressure and temperature conditions resulting from a loss-of-coolant accident (LOCA).

This leakage rate margin shall reflect consideration of

a. the effects of potential energy sources that are not included in the determination of the peak conditions, such as energy in steam generators and energy from metal-water and other chemical reactions that may result from degradation but not total failure of emergency core cooling functioning.

b. the limited experience and experimental data available for defining accident phenomena and containment responses.

c. The conservatism of the calculational model and input parameters.

3. evaluate the pressure capacity at which the structural integrity is intact and a failure leading to a significant release of fission products does not occur.

This technical report provides details of the analysis in report form with the following information

a. calculated static pressure capacity.

b. dynamic pressure capacity, if applicable (static pressure capacity reduced to account for dynamic amplification effects).

c. associated failure modes.

d. criteria governing the original design and criteria used to establish failure.

e. analysis details and general results, which include:

i) modeling details. ii) description of computer code(s). iii) material properties and material modeling. iv) loading and loading sequences. v) failure modes. vi) interpretation of results, with assumptions made in the analysis and test data (if relied upon) clearly stated and technically justified. © Copyright 2022 by NuScale Power, LLC 2

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0

f. appropriate engineering drawings adequate to allow verification of modeling and evaluation of analyses employed for the containment structure.

The CNV ultimate pressure integrity calculation uses multiple, non-linear, finite-element analyses to evaluate failure criteria established for bolted connections, shell regions away from concentrations, and buckling in the top and bottom heads. This report presents the methodology used to determine the CNV ultimate pressure integrity and the value of the ultimate pressure for the CNV. The ultimate pressure calculation follows the methodology provided in RG 1.216. © Copyright 2022 by NuScale Power, LLC 3

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 1.0 Introduction 1.1 Purpose This report describes the methodology, ultimate pressure, and method of failure for the CNV internal pressure capacity for a beyond design basis LOCA. This report and methodology is in accordance with Standard Review Plan Section 3.8.2 (Reference 3) and Nuclear Regulatory Commission (NRC) Regulatory Guide (RG) 1.216 (Reference 1). 1.2 Scope This report provides the methodology for developing the CNV ultimate pressure integrity for the NuScale standard plant CNV. The 10 CFR 50, Appendix A, General Design Criterion (GDC) 50, Containment Design Basis, requires that, the reactor containment structure and its internal components can accommodate, without exceeding the design leakage rate and with sufficient margin, the calculated pressure and temperature conditions caused by a LOCA. This report discusses the non-linear (plastic), three-dimensional (3-D), finite element analyses that conform to the guidelines in NUREG/CR-6906 (Reference 2). This report addresses CNV penetrations and includes an evaluation of buckling of the CNV heads. This report addresses the following six aspects: design internal pressure. static pressure capacity. dynamic pressure capacity. failure modes. criteria used to establish failures for bolted connections shell regions away from concentrations buckling of the top and bottom heads analysis details, including: modeling details material properties loading and loading sequence computer codes used failure modes interpretation of results This report does not provide the ultimate pressure capacity for as-built plants. Creation of these limits is on a module-specific basis with consideration of as-built material properties and as-built CNV dimensions. The as-built evaluation may reference the methods in this © Copyright 2022 by NuScale Power, LLC 4

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 report to develop the module-specific ultimate pressure capacity. Standard Design Approval application Final Safety Analysis Report Section 6.2.5 addresses the combustible gas inside containment and is not within the scope of this report as a combustible gas event is not credible with the incorporation of passive autocatalytic recombiners that are sized to remove oxygen (<4 percent), ensuring that hydrogen combustion does not occur inside the CNV. 1.3 Abbreviations and Definitions The abbreviations used in this report are shown in Table 1-1. Definitions of common terms used in the report are shown in Table 1-2. Table 1-1 Abbreviations Term Definition ASME American Society of Mechanical Engineers BPVC Boiler and Pressure Vessel Code CNV containment vessel CRDM control rod drive mechanism FEA finite element analysis FEM finite element model GDC General Design Criterion HTC heat transfer coefficient ID inside diameter LOCA loss-of-coolant accident LWR light water reactor NRC Nuclear Regulatory Commission OD outside diameter PZR pressurizer RG Regulatory Guide RPV reactor pressure vessel SG steam generator Table 1-2 Definitions Term Definition Bolt Bolt and stud are used interchangeably for a headless, threaded rod fastener. CNV closure flanges Set of large-diameter flanges located on the CNV that are unbolted during a refueling outage to provide access to the reactor pressure vessel (RPV). Preload The tension created in a fastener when it is tightened. O-ring A seal in the form of a ring (typically with a circular cross section) used in bolted flange connections. © Copyright 2022 by NuScale Power, LLC 5

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 2.0 Background The NuScale Power Module (NPM) design differs from other light water reactor (LWR) designs currently in operation in that the CNV design, fabrication, inspection, testing, and stamping complies with the rules for an ASME BPVC Class 1 pressure vessel. The design pressure for the CNV is approximately a factor of 20 higher than other LWR designs currently in operation. The CNV is partially immersed in the reactor pool to facilitate heat removal. The CNV provides a barrier against the release of fission products while accommodating the calculated pressures and temperatures resulting from postulated mass and energy release inside containment. The CNV withstands the full spectrum of postulated mass and energy releases (i.e., LOCA and non-LOCA). This report discusses the methodology and modes of failure for a beyond design basis LOCA event that creates an increasing internal pressure. It determines the pressure at which containment integrity is lost. This report does not evaluate dynamic pressure as a result of hydrogen detonation. As discussed in Standard Design Approval application Final Safety Analysis Report Section 6.2.5, the NuScale Power Plant US460 standard design includes a passive autocatalytic recombiner sized to remove oxygen (<4 percent), ensuring that hydrogen combustion does not occur inside the CNV. 2.1 Regulatory Requirements 2.1.1 CFR 50 Appendix A General Design Criterion 50 and 10 CFR 50.44 In accordance with GDC 50 and 10 CFR 50.44, the reactor containment structure, including access openings, penetrations, and the containment heat removal system shall accommodate, without exceeding the design leakage rate and with sufficient margin, the calculated pressure and temperature conditions resulting from a LOCA. This margin shall reflect consideration of: the effects of potential energy sources excluded from the determination of the peak conditions, such as energy in steam generators (SGs) and, as required by 10 CFR 50.44, energy from metal-water and other chemical reactions that may result from degradation but not total failure of emergency core cooling functioning the limited experience and experimental data available for defining accident phenomena and containment responses the conservatism of the calculational model and input parameters 2.1.2 CFR 52.137 The application must contain a level of design information sufficient for the Commission to judge the applicant's proposed means of assuring that construction conforms to the design and to reach a final conclusion on safety questions associated with the design before granting the certification. The information submitted for a © Copyright 2022 by NuScale Power, LLC 6

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 design certification must include performance requirements and design information sufficiently detailed to permit the preparation of acceptance and inspection requirements by the NRC and procurement specifications and construction and installation specifications by an applicant. 2.1.3 Regulatory Guide 1.216 - Containment Structural Integrity Evaluation for Internal Pressure Loading above Design Basis Pressure Regulatory Guide 1.216 provides guidance for the methods to (1) predict the internal pressure capacity for containment above design basis accident pressure, (2) demonstrate containment structural integrity related to combustible gas control, and (3) demonstrate containment structural integrity for Class MC steel containment through an analysis to prevent and mitigate severe accidents. The basis of RG 1.216 does not include considerations for containments designed and fabricated in accordance with ASME BPVC Class 1 requirements. Specifically, this report addresses RG 1.216, Section C.1.k, which states that the report should submit details of the analysis and results with design internal pressure as defined in Subarticle NE-3100 "General Design" and in Subarticle CC "Load Criteria. calculated static pressure capacity. dynamic pressure capacity, if applicable (static pressure capacity reduced to account for dynamic amplification effects). associated failure modes. criteria governing the original design and criteria used to establish failure. analysis details and general results, which include

                  -    Modeling details
                  -    description of computer code
                  -    material properties and material modeling
                  -    loading and loading sequences
                  -    failure modes
                  -    interpretation of results, with all assumptions made in the analysis and test data (if relied upon) clearly stated and technically justified appropriate engineering drawings adequate to allow verification of modeling and evaluation of analyses employed for the containment structure.

2.1.4 NUREG/CR-6906 - Containment Integrity Research at Sandia National Laboratories NUREG/CR-6906 summarizes research performed at Sandia National Laboratories for nearly 30 years on nuclear power plant steel containment structures and their response to extreme loads beyond their design basis. Containments considered in © Copyright 2022 by NuScale Power, LLC 7

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 this report include large pressurized water reactor and boiling water reactor steel, as well as, concrete-reinforced containment designs. NUREC/CR 6906 does not consider containments designed and fabricated to ASME BPVC, Section III Class 1 requirements.The report summarizes the results of the efforts, and identifies common themes. Appendix A provides guidelines for containment capacity analysis to evaluate containment structures subject to beyond design basis accident loads. © Copyright 2022 by NuScale Power, LLC 8

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.0 Analysis of Containment Vessel for Ultimate Pressure Integrity 3.1 Failure Criteria for Containment Vessel Ultimate Pressure Capacity The failure criteria guidelines that determine the ultimate pressure capacity of the CNV are in Reference 1, Section C.1. The CNV is assumed to fail when one of the following criteria is met.

1. The CNV reaches a maximum membrane strain away from discontinuities of 1.5 percent.

2. Loss of bolt preload occurs at any bolted opening.

3. A flange gap exceeds the calculated allowable values determined in Appendix A at the inner O-ring of any bolted opening at any point around the circumference of the opening.

4. Solution divergence occurs.

5. Buckling occurs at the knuckle of the upper or lower CNV head.

For failure criterion 1, the maximum membrane strain (hoop membrane strain) away from discontinuities (e.g., openings, changes in diameter) is the maximum hoop strain calculated through the CNV wall at a distance of 2.5 Rt , where R is the inside radius of the CNV and t is the wall thickness at the location of the discontinuity. Comparison of the total calculated leakage against a defined total leakage limit determines the potential for leakage at pressures below the determined pressure capacity (Reference 1). Because there is no leakage limit (or leakage acceptance criterion), the third bulleted failure criterion above conservatively assumes that unacceptable leakage occurs when allowable gap sizes determined in Appendix A are exceeded. Gaps at the inner O-ring seal are the average of the outside edge of the inner mating surface and the inside edge of the middle mating surface (i.e., the edges of the inner seal groove). Violation of the gap criterion at any point around the circumference of the opening is conservatively interpreted as a failure to this criterion. Flange leakage is negligible at or below the small flange gaps associated with the third bulleted criterion above per Appendix A. 3.2 Methodology A combination of finite element analysis (FEA) and classical hand calculations is used to determine the ultimate pressure capacity of the CNV. Non-linear static structural 3-D FEA uses multilinear kinematic hardening material properties to determine the internal pressures at which the strain exceeds 1.5 percent total membrane hoop strain, as well as the internal pressures at which the flange gaps at the bolted openings (CNV closure flange, pressurizer [PZR] access port, manway, or the control rod drive mechanism [CRDM] access port) exceed the O-ring seal allowable springback values in Appendix A. Small strain is assumed for all FEA models (i.e., the large deflection option is turned off). © Copyright 2022 by NuScale Power, LLC 9

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Hand calculations are used to determine the internal pressures at which buckling occurs in the torispherical upper and lower heads in accordance with Section 4.3.6 of Reference 9. Hand calculations are also used to determine the pressure at which the stud preload is exceeded in accordance with Appendix E of Reference 8. 3.2.1 Failure Criteria and Ultimate Pressure Capacity The failure criteria that determine the ultimate pressure capacity of the CNV are in RGg1.216 (Reference 1) and are in Section 3.1. 3.2.2 Finite Element Analysis Model Summary Because of the complexity and computational cost of creating a single global FEA model (FEM) of the CNV, four models are used to evaluate the CNV closure flange (Figure 3-1 through Figure 3-3), the PZR access port (Figure 3-4 through Figure 3-7), the manway port (Figure 3-8 through Figure 3-11), and the CRDM access port (Figure 3-12 through Figure 3-14). The CNV closure flange FEM is also used to evaluate strain away from discontinuities in the CNV. Various elements of the model are de-featured for simplicity and to reduce computational time as discussed by Section 3.4.1. All studs are modeled using the equivalent tensile area diameter of the thread form. Tensile area is calculated using Equation 1 and Equation 2 below from Reference 11. Tensile area for steels over 100,000 psi ultimate tensile strength is calculated in Equation 3-1. d 2min 0.16238 2 A t = ------------- - ------------------- Equation 3-1 2 n Where: d 2min = the minimum pitch diameter of external thread per Reference 10. n = the number of threads per inch. Then, the equivalent diameter is: 4A D eq = --------t Equation 3-2 The four models are briefly summarized below. © Copyright 2022 by NuScale Power, LLC 10

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 CNV Pressure Capacity Models CNV closure flange model A 3-D model that utilizes 1/128th symmetry (because there are 64 studs) of the entire height of the CNV is used to determine the ultimate pressure sealing capability of the CNV closure flange, as well as the ultimate pressure associated with the 1.5 percent strain criterion for the shell. PZR access port model A 3-D model that utilizes half-symmetry of the upper CNV (upper flange and above) is used to determine the ultimate pressure sealing capability of the PZR access port. Manway port model A 3-D model that utilizes half-symmetry of the upper CNV (upper flange and above) is used to determine the ultimate pressure sealing capability of the manway port. The model is used to evaluate the manway port rather than the SG access port. While the SG access port and the manway port are identical in size and geometry, the external temperature of the manway port is higher than that of the SG access port and is therefore conservative for this analysis. CRDM access port model A 3-D model of the full circumference of the CNV upper head region and upper portion of the CNV shell is utilized to determine the ultimate pressure sealing capability of the CRDM access port. 3.2.3 Buckling of Containment Vessel Heads Under internal pressure, a potential failure mode of ellipsoidal and torispherical heads is buckling resulting from a hoop compression zone in the knuckle region according to Reference 1. An evaluation of buckling of the CNV upper and lower heads is performed using torispherical head buckling equations from Section 4.3.6 of Reference 9. These equations provide a conservative value of the internal pressure required to produce knuckle buckling. The following is from Section 4.3.6 of Reference 9. Step 1. Determine the inside diameter, D, and assume values for the crown radius, L, the knuckle radius, r, and the wall thickness, t. Step 2. Compute the head L/D, r/D, and L/t ratios and determine if the following equations are satisfied. If the equations are satisfied, then proceed to Step 3; otherwise, the head shall be designed in accordance with Part 5. L 0.7 ---- 1.0 D r

                  ----  0.06 D

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 L 20 --- 2000 t Step 3. Calculate the following geometric constants. 0.5D - r th = arccos -------------------- , radians Equation 3-3 L-r Lt th = --------- , radians Equation 3-4 r 0.5D - r R th = ---------------------------------- + r for th < th Equation 3-5 cos ( th - th ) R th = 0.5D for th th Equation 3-6 Step 4. Compute the coefficients C1 and C2 using the following equations. r r C 1 = 9.31 ---- - 0.086 for ---- 0.08 Equation 3-7 D D r r C 1 = 0.692 ---- + 0.605 for ---- 0.08 Equation 3-8 D D r C 2 = 1.25 for ---- 0.08 Equation 3-9 D r r C 2 = 1.46 - 2.6 ---- for ---- > 0.08 Equation 3-10 D D Step 5. Calculate the value of internal pressure expected to produce elastic buckling of the knuckle. 2 C1 ET t P eth = ------------------------------------

                                                                                        -                              Equation 3-11 R

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Step 6. Calculate the value of internal pressure that results in a maximum stress in the knuckle equal to the material yield strength. C3 t P y = ------------------------------------- - Equation 3-12 R C 2 R th -------- - 1 th 2r Because the allowable stress at the design temperature of 600 degrees F is governed by time-independent properties, then C 3 is the material yield strength at design temperature. C3 = Sy Equation 3-13 Step 7. Calculate the value of internal pressure expected to result in a buckling failure of the knuckle. P ck = 0.6P eth for G 1.0 Equation 3-14 0.77508G - 0.20354G 2 + 0.019274G 3 P ck = ------------------------------------------------------------------------------------------------------------ P y for G > 1.0 Equation 3-15 1 + 0.19014G - 0.089534G 2 + 0.0093965G 3 where: P eth G = --------- - Equation 3-16 Py Step 8. Calculate the allowable pressure based on a buckling failure of the knuckle. P ck P ak = ------- - Equation 3-17 1.5 3.2.4 Tight Joint Evaluation The equations to calculate the stud load needed to maintain a tight joint are in Appendix E of Reference 8. These equations are utilized to determine an internal pressure needed to overcome the stud preload applied in the analysis. Table 4-2 shows the calculations for the loads to maintain tight joints with the applicable preloads. As noted in the general note to Table XI-3221.1-1 of Reference 8, the table gives m and y values for many commonly used gasket types, materials, and contact facings, but these values are not mandatory. For the metal O-rings used for the CNV bolted closures, there is no corresponding applicable gasket type listed in Table XI-3221.1-1 of Reference 8. Therefore, as an alternative calculation, determination of the seal contact compression load (Hi and Ho) using vendor supplied seal seating © Copyright 2022 by NuScale Power, LLC 13

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 loads given in pounds per linear inch in conjunction with the seal circumferential lengths is made. The equations used to determine the pressure required to overcome the stud preload are shown below. H i = the total seating load to compress inside seal, lb H i = Y 2 ( L i ) = Y 2 ( G i ) Equation 3-18 H o = the total seating load to compress outside seal, lb H o = Y 2 ( L o ) = Y 2 ( G o ) Equation 3-19 where: L i = the circumferential length of the inside seal, in. G i = the circumferential centerline diameter of the inside seal, in. L o = the circumferential length of the outside seal, in. G o = the circumferential centerline diameter of the outside seal, in. Y 2 = the seating load of the seal per circumferential inch, lb/in H = the total hydrostatic end force based on the outer seal diameter H = 0.785 G ( P ) 2 Equation 3-20 o where: P = the internal pressure The minimum required total stud load, W m1 , is then calculated. W m1 = H + H i + H o Equation 3-21 © Copyright 2022 by NuScale Power, LLC 14

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 The required individual stud load is then determined by dividing by the number of studs, n. W m1 F m1 = ----------

                                                            -                             Equation 3-22 n

The internal pressure that produces an individual stud load equal to the applied stud preload is considered to be the failure pressure. 3.3 Geometry and Material Inputs This report uses the following geometry and material inputs. 3.3.1 Geometry The geometry used in this evaluation are defeatured 3-D solid models of the following sub-assemblies: CNV upper head sub-assembly (location of the CRDM access port) CNV upper shell sub-assembly (location of the CNV manway) CNV lower assembly (location of the lower portion of the CNV closure flange) CNV upper SG access sub-assembly (location of the PZR access port) and SG access port CNV upper flange sub-assembly (location of the upper portion of the CNV closure flange) CNV closure bolt assembly 3.3.2 Materials Table 3-1 shows the materials for the components in this report. Table 3-1 Materials Component(1) Material Lower Support Skirt SA-182, Type F304 Lower Head SA-965, Grade FXM-19 Lower Core Region Shell SA-965, Grade FXM-19 Lower Transition Shell SA-965, Grade FXM-19 Lower Shell SA-336, Grade F6NM Lower Flange SA-336, Grade F6NM Upper Flange SA-336, Grade F6NM Upper Support Ledge Shell SA-336, Grade F6NM Upper SG Access Shell SA-336, Grade F6NM Upper Intermediate Shell SA-336, Grade F6NM © Copyright 2022 by NuScale Power, LLC 15

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table 3-1 Materials (Continued) Component(1) Material Upper Manway Access Shell SA-336, Grade F6NM Upper Seismic Support Shell SA-336, Grade F6NM Upper Head SA-336, Grade F6NM CRDM Top Head Cover SA-182, Grade F6NM(1) Manway/SG Access Cover SA-182, Grade F6NM(1) PZR Heater Access Cover SA-182, Grade F6NM(1) Studs/Nuts Washers SB-637, Alloy N07718 Notes: 1.SA-336, Grade F6NM material properties are utilized to represent the containment vessel control rod drive mechanism top head cover. This material has identical physical properties as SA-182, Grade F6NM; therefore, this has no impact on the results. 3.3.3 Material Properties The material properties used in this report, for the components identified in Section 3.3.2, are obtained from Reference 6. Material properties correspond to the CNV design temperature. The FEA models use multilinear kinematic hardening material properties. Material properties considered in this evaluation are obtained at CNV design temperature. The nonlinear portion of the stress-strain material curves are derived in accordance with ASME BPVC Section VIII Division II, Annnex 3-D (Reference 9), with the first point (zero strain point) being at the minimum material yield strength listed in Section II, Part D of the ASME BPVC (Reference 6). The guidance of Reference 1, Section C.1.d specifies that the non-linear stress-strain curve be based on the ASME BPVC minimum yield strength and the stress-strain beyond yield representative of the specific grade. Appendix B shows the stress versus strain data used to generate the non-linear portion of the material curves. Table 3-2 Material Properties at Design Temperature (600 Degrees Fahrenheit) Modulus of Ultimate Poissons Ratio Elasticity Yield Strength Tensile Material (unitless) (psi) Strength (x106 psi) (psi) SA-182, Grade F304 0.31 25.3 18,400 63,400 SA-336, Grade F6NM 0.31 26.2 78,500 105,100 SA-965, FXM-19 0.31 25.3 37,400 87,700 SB-637 Alloy N07718 0.31 26.8 135,300(1) 166,870(1) Notes: 1.SB-637 Alloy N07718 yield strength is calculated as 3Sm and ultimate tensile strength is extrapolated based on the ratio of yield strength to ultimate strength at room temperature. © Copyright 2022 by NuScale Power, LLC 16

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.4 Three-Dimension Model Geometry A 3-D representation of the CNV is used to compute the vessel strain and the bolted opening integrity due to internal pressure. A 2.8125 degree sector (1/128) of the full height of the CNV is used to evaluate vessel strain away from discontinuities as well as to evaluate the leakage integrity of the CNV closure flange. For the PZR access opening and manway evaluations, the 3-D representation models half-symmetry representations of the CNV from the upper flange and above. For the CRDM access port evaluation, the 3-D representation models the full circumference of the CNV, including the upper head assembly and the upper CNV shell. ANSYS SpaceClaim is used to import the generic computer-aided design files for the CNV and combine them to form the CNV geometry. Various elements of the geometry are de-featured. Simplifications to the geometry for the purpose of this analysis are in Section 3.4.1. Figure 3-1, Figure 3-2, and Figure 3-3 display the model geometry used to compute the vessel strain as well as to evaluate the CNV closure flange because of internal pressure. Figure 3-4, Figure 3-5, Figure 3-6, and Figure 3-7 display the model geometry used to evaluate the PZR access port opening in the CNV shell. Figure 3-8, Figure 3-9, Figure 3-10, and Figure 3-11 display the model geometry used to evaluate the manway opening in the CNV shell. Figure 3-12, Figure 3-13, and Figure 3-14 display the model geometry used to evaluate the CRDM access port opening in the CNV upper head. © Copyright 2022 by NuScale Power, LLC 17

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-1 Three Dimensional Model Geometry - Containment Vessel Closure Flange and Strain Evaluation - Full View ((

                                                                                                }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-2 Three Dimensional Model Geometry - Containment Vessel Closure Flange and Strain Evaluation - Closure Flange Close-up ((

                                                                                              }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-3 Three Dimensional Model Geometry - Containment Vessel Closure Flange and Strain Evaluation - Top View ((

                                                                                               }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-4 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Full View ((

                                                                                               }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-5 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Pressurizer Access Port Region ((

                                                                                             }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-6 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Pressurizer Access Port Region Section View ((

                                                                                          }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-7 Three Dimensional Model Geometry - Containment Vessel Pressurizer Access Port Evaluation - Pressurizer Access Port Region Section View Close-up ((

                                                                                         }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-8 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Full View ((

                                                                                           }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-9 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Manway Port Region ((

                                                                                              }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-10 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Manway Port Region Section View ((

                                                                                            }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-11 Three Dimensional Model Geometry - Containment Vessel Manway Port Evaluation - Manway Port Region Section View Close-up ((

                                                                                          }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-12 Three Dimensional Model Geometry - Containment Vessel Control Rod Drive Mechanism Access Port Evaluation - Full View ((

                                                                                           }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-13 Three Dimensional Model Geometry - Containment Vessel Control Rod Drive Mechanism Access Port Evaluation - Control Rod Drive Mechanism Access Port Region ((

                                                                                   }}2(a),(c).ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-14 Three Dimensional Model Geometry - Containment Vessel Control Rod Drive Mechanism Access Port Evaluation - Control Rod Drive Mechanism Access Port Region Close-up ((

                                                                                   }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.4.1 Modeling Simplification The FEA utilizes modeling simplifications, allowing for simplified meshing, reduced number of elements, and reduced run times. These modeling simplifications do not affect the overall structural behavior of the models. This is standard industry practice for performing FEA. Per the guidance in Appendix A of Reference 2, the effect of small CNV penetrations on the overall containment response can be ignored. The proximity of these penetrations to CNV bolted openings does not negatively impact the ultimate pressure capacity of the CNV. The electrical penetrations, top support structure support with frame, and piping penetrations (i.e., feedwater lines, steam lines, containment isolation valves) do not impact the ultimate pressure capacity of the CNV, and some FEMs exclude them. In addition, the bolted openings with an inner nozzle diameter smaller than nominal pipe size 18 do not limit the ultimate pressure capacity of the CNV, and the FEA does not evaluate them. Because the force on a bolted flange cover is proportional to the square of the diameter on which the pressure acts, the larger-diameter bolted openings fail before smaller-diameter bolted openings. Previous studies show that these smaller openings are not limiting. Section 3.5 identifies the following modeling simplifications made to the 3-D solid models for use in the ANSYS FEAs. Chamfers, small radius fillets, alignment features are removed. O-ring grooves in bolted covers not being evaluated in each FEM are removed. CNV nozzle penetrations (except for the CRDM access port FEM) are removed. Simplified bolted openings smaller than nominal pipe size 18. Simplified bolted openings are not being evaluated in each FEM. Top support structure frame and supports are removed. Vent holes from support skirt are removed. Components external to the CNV shell (e.g., support lugs, lifting trunnions) are removed. The welds are full-penetration welds and modeled as part of the base metal and are not modeled as a separate, integral parts. CNV Class 1 welds are full-penetration, shop-fabricated welds whose mechanical properties are at least equal to the properties of the parent material. Failure of the CNV does not occur at the welds or in the heat-affected zone of the parent material as a result of reduced material properties. The CNV Class 1 welds are post-weld heat treated, and fully inspected before going into service to minimize residual stresses at the welds. © Copyright 2022 by NuScale Power, LLC 32

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.5 Finite Element Models Thermal and structural analyses are performed using 3-D FEMs. The FEMs for these evaluations are constructed in ANSYS 19R2. 3.5.1 Mesh The 3-D steady-state thermal models are constructed using higher-order elements, a combination of Solid87 and Solid90 elements. The 3-D static structural models are also constructed of higher-order elements, a combination of Solid186 and Solid187 elements. There are a sufficient number of elements through the thickness in regions of interest. The average element quality for the CNV closure flange/strain evaluation 3-D FEM is 0.78. The average element quality for the containment vessel pressurizer access port evaluation 3-D FEM is 0.61. The average element quality for the CNV manway port evaluation 3-D FEM is 0.57. The average element quality for the containment vessel control rod drive mechanism access port evaluation 3-D FEM is 0.61. These are large models used for determining contact gaps at the access port covers for sealability evaluation and the majority of lower quality elements are far from the area of interest. The regions of the mating surfaces on the covers and the vessels are high quality swept quad elements to ensure accuracy of results. An element quality of 1.0 is a perfect mesh. The 3-D FEMs capture strains, and the applicable bolted opening contact gap data evaluates sealability. Figure 3-15 and Figure 3-16 show the mesh for the CNV closure flange model. Figure 3-17, Figure 3-18, and Figure 3-19 show the mesh for the PZR access port model. Figure 3-20, Figure 3-21, and Figure 3-22 show the mesh for the manway model. Figure 3-23, Figure 3-24, and Figure 3-25 show the mesh for the CRDM access port model. 3.5.2 Contact Figure 3-26 displays the contact regions and contact definition types for the CNV closure flange FEM. Figure 3-27 displays the typical contact regions and contact definition types for the PZR access port, manway, and CRDM access port FEMs. Frictional contact is defined between the cover mating surfaces and the vessel mating surfaces, with a friction coefficient of 0.2 defined. The coefficient of 0.2 for wet steel applies to CNV bolted openings. The coefficient of friction of wet steel is conservatively assumed to be equal to that of greased steel based on the value in Reference 11. The manway port and CRDM access port locations that are not submerged in the pool water conservatively use the value for wet steel. Frictional contact is typically defined between the cover and the washer and between the washer and the nut. Bonded contact is defined between the studs and nuts and between the studs and vessel holes. Frictionless contact is defined between the stud and the washer as well as the stud and the cover holes. © Copyright 2022 by NuScale Power, LLC 33

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-15 Containment Vessel Closure Flange Finite Element Model Mesh - Full Model ((

                                                                                     }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-16 Containment Vessel Closure Flange Finite Element Model Mesh - Closure Flange Region and Mating Surface Details ((

                                                                                               }}2(a),(c),ECI Note, this image is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-17 Containment Vessel Pressurizer Access Port Finite Element Model Mesh - Full Model ((

                                                                                    }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-18 Containment Vessel Pressurizer Access Port Finite Element Model Mesh - Pressurizer Access Port Region ((

                                                                                               }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-19 Containment Vessel Pressurizer Access Port Finite Element Model Mesh - Cross-Section Close-up View of Mating Surfaces Region ((

                                                                                          }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-20 Containment Vessel Manway Port Finite Element Model Mesh - Full Model ((

                                                                                     }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-21 Containment Vessel Manway Port Finite Element Model Mesh - Manway Port Region ((

                                                                                    }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-22 Containment Vessel Manway Port Finite Element Model Mesh - Cross-Section Close-up View of Mating Surfaces Region ((

                                                                                             }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-23 Containment Vessel Control Rod Drive Mechanism Access Port Finite Element Model Mesh - Full Model ((

                                                                                              }}2(a),(c).ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-24 Containment Vessel Control Rod Drive Mechanism Access Port Finite Element Model Mesh - Control Rod Drive Mechanism Access Port Region ((

                                                                                     }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-25 Containment Vessel Control Rod Drive Mechanism Access Port Finite Element Model Mesh - Cross-Section Close-up View of Mating Surfaces Region ((

                                                                                     }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-26 Containment Vessel Closure Flange Finite Element Analysis Model Contact Definition ((

                                                                                            }}2(a),(c),ECI Note, this figure is meant to be viewed in color. For the CNV closure flange, the washer is bonded to the nut as these are one integral component.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-27 Typical Contact Definition for Pressurizer Access Port, Manway, and Control Rod Drive Mechanism Access Closures ((

                                                                                           }}2(a),(c),ECI Note, this image is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.6 Loads and Boundary Conditions 3.6.1 Loads 3.6.1.1 Steady-State Thermal Steady-state thermal loads are first evaluated in the four FEMs to determine temperature distribution to be imported into the subsequent static structural evaluations. The FEAs apply a uniform temperature of 70 degrees F, which is utilized in the subsequent static structural run during the stud preload steps. Then a design temperature of 600°F is applied to the CNV ID with a heat transfer coefficient (HTC) of (( }}2(a),(c),ECI. For regions of the CNV submerged in the pool water (below (( }}2(a),(c),ECI), the nominal pool temperature of 100°F is applied to the CNV OD with an HTC of (( }}2(a),(c). For regions of the CNV above the pool water level, the CNV OD with a film coefficient of (( }}2(a),(c) uses the maximum allowed temperature under the bioshield of 140 degrees F. Applying the conservative design temperature of 600 degrees F isothermally to the entirety of the CNV is an unrealistic and overly conservative condition for this evaluation. A small area on the CNV head surrounding the main steam nozzles is responsible for generating the design condition temperature of 600 degrees F, whereas the remainder of the CNV does not reach these temperatures; however, the entire inside of the CNV is 600 degrees F for this evaluation. Furthermore, a large portion of the CNV is submerged in a pool of 100°F water that significantly cools the containment vessel OD and closure studs; the ambient air temperature above the pool in containment is limited to 140 degrees F; therefore, the outer CNV below and above the pool level are 100 degrees F and 140 degrees F, respectively, for this evaluation. In order to perform a more realistic temperature profile and a more accurate evaluation of ultimate pressure capacity, the assumed HTCs are applied accordingly in a steady-state thermal FEA. The conservatively low OD HTC maximize the temperature of the closure flanges and studs, and subsequently maximize the thermal expansion of the studs for the realistic pool and ambient air temperatures applied. A high HTC applied to the ID produces an ID metal temperature equivalent to the 600 degrees F design temperature for the steady-state thermal FEA. A test run with an HTC of (( }}2(a),(c) on the containment vessel ID that showed negligible difference in the temperature profile or flange gap results proves the adequacy of the applied (( }}2(a),(c) on the ID. Figure 3-28, Figure 3-29, Figure 3-30, Figure 3-31, Figure 3-32, Figure 3-33, Figure 3-34, Figure 3-35, Figure 3-36, Figure 3-37, and Figure 3-38 display the locations of convection loads on FEMs. Surface-to-surface radiation is applied between the studs and the cover stud holes; in the CNV closure flange case, surface-to-surface radiation applies between the stud and the flange stud holes. The surface-to-surface radiation has an emissivity value of 0.4 as shown in Figure 3-39 and Figure 3-40. An emissivity © Copyright 2022 by NuScale Power, LLC 47

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 of 0.4 is an upper bound for polished stainless steel (Figure 12.18 of Reference 12) and is applied between the studs and the stud holes in the bolted opening covers. Table 3-3 Steady-State Thermal Parameters HTC Location Temp (degrees F) (BTU/hr-ft2-°F) CNV ID 600 (( CNV OD (Submerged) 100 CNV OD (Above Pool Level) 140 }}2(a),(c),ECI

    © Copyright 2022 by NuScale Power, LLC 48

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-28 Convection Application for Containment Vessel Inside Diameter - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                        }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-29 Convection Application for Containment Vessel Outside Diameter above Pool Level - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                        }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-30 Convection Application for Containment Vessel Outside Diameter below Pool Level - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                        }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-31 Convection Application for Containment Vessel Inside Diameter - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                             }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-32 Convection Application for Containment Vessel Outside Diameter above Pool Level - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                           }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-33 Convection Application for Containment Vessel Outside Diameter below Pool Level - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                           }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-34 Convection Application for Containment Vessel Inside Diameter - Manway Port Finite Element Analysis Model ((

                                                                                                }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-35 Convection Application for Containment Vessel Outside Diameter above Pool Level - Manway Port Finite Element Analysis Model ((

                                                                                            }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-36 Convection Application for Containment Vessel Outside Diameter below Pool Level - Manway Port Finite Element Analysis Model ((

                                                                                            }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-37 Convection Application for Containment Vessel Internal Surfaces - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                       }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-38 Convection Application for Containment Vessel External Surfaces - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                       }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-39 Typical Application of Stud/Cover Surface-to-Surface Radiation ((

                                                                                         }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-40 Application of Stud/Flange Surface-to-Surface Radiation for Closure Flange ((

                                                                                      }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.6.1.2 Static Structural 3.6.1.2.1 Temperatures The static structural evaluation imports the temperature profiles from the steady-state thermal runs. Load steps 1 and 2 are the application of stud preload with no internal pressures applied. These steps apply a temperature of 70 degrees F. For subsequent load steps with applied internal pressures, Section 3.6.1.1 discusses the applied temperature profile. 3.6.1.2.2 Stud Preload Table 3-4 shows the applied nominal stud preload for each stud in load step 1. The values lock for load step 2 and subsequent load steps where internal pressure is applied. Because the CNV closure flange FEM models half a stud, a load of (( }}2(a),(c),ECI is applied as the preload force. Figure 3-41, Figure 3-42, Figure 3-43, Figure 3-44, Figure 3-45, Figure 3-46, and Figure 3-47 show stud preload application for FEMs. Table 3-4 Stud Preloads Applied ((

                                                                                                      }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-41 Stud Preload Application - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                           }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-42 Stud Preload Application - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                     }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-43 Stud Preload Application - Body Selection - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                           }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-44 Stud Preload Application - Manway Port Finite Element Analysis Model ((

                                                                                     }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-45 Stud Preload Application - Body Selection - Manway Port Finite Element Analysis Model ((

                                                                                      }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-46 Stud Preload Application - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                           }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-47 Stud Preload Application - Body Selection - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                             }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.6.1.2.3 Seal Seating Load The FEAs simulate seal seating loads via an equivalent pressure load based on the size of the seal grooves and the vendor-specified seating loads given in pounds per linear inch. The equivalent pressure loads are applied to the seating surfaces in the modeled seal grooves as well as on the opposing surfaces (either on the vessel mating surfaces or the upper flange). Seating loads are applied for load steps as shown in Table 3-5. The FEM conservatively applies the full seating load for load steps where there are gaps between mating surfaces, which would relieve the seating load. Figure 3-48 shows the typical application regions for the seal seating pressure. Table 3-5 Seal Seating Loads ((

                                                                                                   }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-48 Seal Seating Pressure Application Area - Typical Application ((

                                                                                         }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.6.1.2.4 Reactor Pressure Vessel Weight and Gravity Loads The RPV weight is applied to the RPV support ledge locations in the CNV closure flange model, the PZR access port model, and the manway port model. Because the CNV closure flange model is a 1/128 sector of the CNV, the summation of the force loads from each of the four containment vessel-reactor pressure vessel ledges ((

                                            }}2(a),(c),ECI is divided by 128 and applied via remote force scoped to a nodal edge at the height location of the containment vessel-reactor pressure vessel ledges since there are no explicitly modeled containment vessel-reactor pressure vessel ledges. For the PZR access port model and manway model, there are two explicitly modeled containment vessel-reactor pressure vessel ledges, and the RPV weight is applied as a force load on the ledge of ((                     }}2(a),(c),ECI lbs. Gravity acceleration loading is applied to all bodies in all models. Both the RPV weight and gravity are applied in all load steps.

3.6.1.2.5 Internal Pressure For the CNV closure flange model, the design internal pressure of 1200 psi is applied in load step 5. The internal pressure is then increased in (( }}2(a),(c),ECI increments in the subsequent load steps up to (( }}2(a),(c),ECI psi. Table 3-6 contains applied internal pressures by load step for the CNV closure flange model. For other models (PZR access port, manway port, and CRDM access port) the design internal pressure of 1200 psi is applied in load step 3 as the initial pressure condition. The internal pressure is then increased in (( }}2(a),(c),ECI psi increments in the subsequent load steps up to (( }}2(a),(c),ECI psi. Table 3-7 contains the applied internal pressure by load step. Multiple substeps are performed for each load step to achieve more resolution of results data. Internal pressures are applied to all internal surfaces up to the centerline of the inner O-ring seal groove of the evaluated opening. Figure 3-49, Figure 3-50, Figure 3-51, and Figure 3-52 display the internal pressure application of all FEMs. © Copyright 2022 by NuScale Power, LLC 72

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table 3-6 Internal Pressures Applied - Containment Vessel Closure Flange Model ((

                                                                                       }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table 3-7 Internal Pressures Applied - Pressurizer Access Port, Manway Port, Control Rod Drive Mechanism Access Port ((

                                                                                              }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-49 Internal Pressure Application Area - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                              }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-50 Internal Pressure Application Area - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                       }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-51 Internal Pressure Application Area - Manway Port Finite Element Analysis Model ((

                                                                                      }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-52 Internal Pressure Application Area - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                                }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.6.1.2.6 Blowoff Loads Applicable blowoff loads are applied as equivalent pressure loads on the CNV head nozzles that are modeled as open nozzles on the CRDM access port FEM. Blowoff loads are applied to the main steam nozzles, feedwater nozzles, containment evacuation nozzles, and various small nozzles. Blowoff loads are based on internal pressure, nozzle inner bore diameter, and nozzle OD. Table 3-8 lists blowoff loads for each nozzle with the corresponding internal pressure. Figure 3-53 and Figure 3-54 display the application of external and internal blowoff loads, respectively. Table 3-8 Nozzle Blowoff Loads Applied in Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                                  }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-53 Applied Nozzle Blowoff Loads - External - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                             }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-54 Applied Nozzle Blowoff Loads - Internal - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                             }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 3.6.2 Boundary Conditions 3.6.2.1 Thermal Boundary Conditions Section 3.6.1.1 documents the thermal loadings for all FEMs. There are no explicit additional thermal boundary conditions applied to the FEMs. 3.6.2.2 Structural Boundary Conditions The CNV closure flange FEM, the PZR access port FEM, and the manway port FEM utilize symmetry. Figure 3-55, Figure 3-56, and Figure 3-57 display the frictionless supports that are defined on symmetry planes. The CNV closure flange FEM models the full height of the CNV; a fixed support at the bottom plane of the CNV support skirt vertically constrains the CNV as shown in Figure 3-58. The PZR access port FEM, manway port FEM, and CRDM access port FEM do not model the full height of the CNV and are constrained at the bottom modeled surfaces. Cylindrical coordinate systems are defined at the center axis at the bottom surface of each of these FEMs, and displacement constraints are defined that allow for radial expansion but constrain the models in the vertical and circumferential directions. Figure 3-59, Figure 3-60, and Figure 3-61 display the displacement constraints that are applied to the PZR access port FEM, the manway port FEM, and the CRDM access port FEM, respectively. © Copyright 2022 by NuScale Power, LLC 82

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-55 Frictionless Constraints - Symmetry Surfaces - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color. Figures are shown zoomed-in for improved visibility. The displayed constraints span the entire height of the CNV.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-56 Frictionless Constraints - Symmetry Surfaces - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                              }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-57 Frictionless Constraints - Symmetry Surfaces - Manway Port Finite Element Analysis Model ((

                                                                                     }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-58 Fixed Support - Support Skirt Bottom Surface - Containment Vessel Closure Flange Finite Element Analysis Model ((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-59 Displacement Constraint - Bottom Surface - Pressurizer Access Port Finite Element Analysis Model ((

                                                                                           }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-60 Displacement Constraint - Bottom Surface - Manway Port Finite Element Analysis Model ((

                                                                                     }}2(a),(c),ECI Note: This figure is intended to be viewed in color

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 3-61 Displacement Constraint - Bottom Surface - Control Rod Drive Mechanism Access Port Finite Element Analysis Model ((

                                                                                             }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 4.0 Results Section 3.2 provides the basis for the methodology and calculations that support the results in this section. 4.1 Containment Vessel Pressure Capacity Based on Flange Gaps The pressure capacity of the CNV is greater than (( }}2(a),(c),ECI because this is the last successful internal pressure evaluated at the limiting location of the manway port. At (( }}2(a),(c),ECI, the flange gap at the manway location is 0.00181 inch, which is less than the calculated allowable seal springback of (( }}2(a),(c),ECI as determined in Appendix A. At the next higher evaluated pressure of (( }}2(a),(c),ECI, the flange gap at the manway location exceeds the (( }}2(a),(c),ECI allowable seal springback of (( }}2(a),(c),ECI and is assumed to exceed allowable leakage rates. It is therefore conservatively assumed that the last successful internal pressure of (( }}2(a),(c),ECI is the ultimate pressure capacity for the manway location, and is the limiting location for the CNV. Table 4-1 displays the pressure capacity of each of the evaluated bolted openings. The manway port and the PZR access port buildups in the CNV shell experience saddle-shaped deformation sometimes referred to as potato chipping due to CNV shell pressure dilation that promotes gaps at the 12 oclock and 6 oclock locations of the openings, which is the cause of the lower pressure capability in these locations. Figure 4-1 and Figure 4-2 show contact gap contour plots for the limiting manway port location at the inner and middle mating surfaces surrounding the inner O-ring seal. Figure 4-3 and Figure 4-4 show similar plots for the PZR access port location as do Figure 4-5 and Figure 4-6 for the CRDM access port location and Figure 4-7 and Figure 4-8 for the CNV closure flange location. Only plots of the inner mating surfaces and middle mating surfaces are shown since these are the locations that ensure the sealing adequacy of the inner O-ring seal. Table 4-1 Pressure Capacity of Bolted Opening due to O-Ring Sealability Access Opening Preload Internal Pressure(1) (lbs) (psi) Manway/SG (( }}2(a),(c),ECI PZR Access (( }}2(a),(c),ECI CRDM Access (( }}2(a),(c),ECI Closure Flange (( }}2(a),(c),ECI Notes: 1)The internal pressure of the last successfully sealed time step is listed for each opening. Failure of the openings occur at pressures above those listed. © Copyright 2022 by NuScale Power, LLC 90

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-1 Contact Gap Plot - Manway Port Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                     }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-2 Contact Gap Plot - Manway Port Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-3 Contact Gap Plot - Pressurizer Access Port Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-4 Contact Gap Plot - Pressurizer Access Port Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-5 Contact Gap Plot - Control Rod Drive Mechanism Access Port Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                                }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-6 Contact Gap Plot - Control Rod Drive Mechanism Access Port Middle Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                                }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-7 Contact Gap Plot - Containment Vessel Closure Flange Inner Mating Surface - (( }}2(a),(c),ECI psi Pressure ((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-8 Contact Gap Plot - Containment Vessel Closure Flange Middle Mating Surface

                                     - (( }}2(a),(c),ECI psi Pressure

((

                                                                                               }}2(a),(c),ECI Note: This figure is intended to be viewed in color.

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 4.2 Tight Joint Evaluation The tight joint evaluation is performed in accordance with Appendix E of Reference 8 with methodology outlined in Section 3.2.4. The equations are solved to determine the internal pressure that overcomes the stud preload for each opening. Table 4-2 shows the results, with the limiting pressure of (( }}2(a),(c),ECI psi occurring on the CRDM access port. The limiting pressure of (( }} 2(a),(c),ECI psi is greater than the limiting pressure capacity of the joint sealability evaluations of (( }}2(a),(c),ECI and is not a limiting condition. © Copyright 2022 by NuScale Power, LLC 99

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0

                                                               }}2(a),(c),ECI Table 4-2 Internal Pressure Required to Overcome Preload

((

 © Copyright 2022 by NuScale Power, LLC 100

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 4.3 Strain Evaluation The methodology described in Section 3.2, as prescribed by Reference 1, evaluates the 1.5 percent strain criterion. Reference 1 suggests evaluating the hoop membrane strain away from discontinuities. This evaluation conservatively evaluates the maximum equivalent total strain against the 1.5 percent strain criterion. ANSYS Workbench does not natively support total global membrane total strain results, and because the failure pressure achieved when using the 1.5 percent criterion is higher than the overall CNV pressure capacity limited by the CNV manway leakage, the strain evaluation utilizes the conservative strain results rather than pursuing methods for reporting hoop membrane strain. With the conservative strain values, a maximum equivalent total strain remains below the 1.5 percent criterion through (( }}2(a),(c),ECI psi. The maximum strain of (( }}2(a),(c) occurs at (( }}2(a),(c),ECI psi in the lower shell at a region near a discontinuity as shown in Figure 4-9. At a pressure between ((

                }}2(a),(c),ECI psi, the evaluation reaches a strain of 1.5 percent.

This evaluation also tracks initial yielding of the vessel shell and bolted opening covers. Initial yielding of the steel vessel shell away from discontinuities occurs in the lower shell core region and begins at approximately (( }}2(a),(c),ECI psi (Figure 4-10); however, the strain at (( }}2(a),(c),ECI psi is very small at 0.0015 percent. For context, the strain in these regions does not reach 0.5 percent strain until (( }}2(a),(c),ECI psi. Similar to the 1.5 percent strain evaluation, the reported strain here is equivalent plastic strain rather than hoop membrane strain for ease of evaluation and conservatism. Initial yielding in the CRDM access port cover occurs at (( }}2(a),(c),ECI psi as shown in Figure 4-11. This yielding is small and occurs at the corner of the stud holes in the cover, which can be attributed to a singularity due to contact. Upon removing the area surrounding the stud holes, the initial yielding in the cover occurs at (( }}2(a),(c),ECI psi as shown in Figure 4-12. Furthermore, the CRDM access port cover does not reach 0.5 percent strain in the evaluation through (( }}2(a),(c),ECI psi internal pressure (including the stud hole region). Initial yielding in the PZR access port cover occurs at (( }}2(a),(c),ECI psi as shown in Figure 4-13. This yielding is small and occurs at the corner of the stud holes in the cover, which can be attributed to a singularity due to contact. Upon removal of the area surrounding the stud holes, the initial yielding in the cover occurs at (( }}2(a),(c),ECI psi as shown in Figure 4-14. Furthermore, the PZR access port cover does not reach 0.5 percent strain in the evaluation through (( }}2(a),(c),ECI psi internal pressure (including the stud hole region). Initial yielding in the manway port cover occurs at (( }}2(a),(c),ECI psi as shown in Figure 4-15. This yielding is small and occurs at the corner of the stud holes in the cover, which can be attributed to a singularity due to contact. Upon removal of the area © Copyright 2022 by NuScale Power, LLC 101

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 surrounding the stud holes, the initial yielding in the cover occurs at (( }}2(a),(c),ECI psi as shown in Figure 4-16. Furthermore, the PZR access port cover does not reach 0.5 percent strain until (( }}2(a),(c),ECI psi internal pressure (including the stud hole region). Figure 4-9 Location of 1.5 Percent Strain ((

                                                                                                    }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-10 Location of Initial Yielding in the Shell away from Discontinuities ((

                                                                                            }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-11 Location of Initial Yielding in the Control Rod Drive Mechanism Access Port Cover ((

                                                                                         }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-12 Location of Initial Yielding in the Control Rod Drive Mechanism Access Port Cover away from Stud Holes ((

                                                                                             }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-13 Location of Initial Yielding in the Pressurizer Access Port Cover ((

                                                                                           }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-14 Location of Initial Yielding in the Pressurizer Access Port Cover away from Stud Holes ((

                                                                                          }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-15 Location of Initial Yielding in the Manway Port Cover ((

                                                                                              }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-16 Location of Initial Yielding in the Manway Port Cover away from Stud Holes ((

                                                                                        }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 4.4 Buckling of Upper and Lower Heads The methodology outlined in Section 3.2.3 is used to evaluate buckling of upper and lower heads. As mentioned in Section 3.2.3, these calculations provide a conservative internal pressure that causes knuckle buckling. 4.4.1 Buckling of Containment Vessel Upper Head The internal pressure that results in buckling in the CNV lower head buckling is (( }}2(a),(c),ECI psi. Equation numbers shown are references to the equation numbers in Section 4.3.6.1 of Section VIII, Division 2 (Reference 9). Containment Vessel Top Head - Knuckle Buckling under Internal Pressure Section 4.3.6.1 of Section VIII, Division 2, Torispherical Heads with the Same Crown and Knuckle Thicknesses. Material properties of SA-336 F6NM at design temperature: 6 Modulus of Elasticity at 600 degrees F (Section II, Part D, Table E T = 26.2 10 psi TM-1) S y = 78500 psi Yield strength at 600 degrees F. (Code Case N-774) ((

                                                                                                      }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-17 Torispherical Head Geometry Calculate geometry ratios: L- = ((

              ---                            }}

2(a),(c),ECI

                                                                       ---r- = ((           5 }}

2(a),(c),ECI L

                                                                                                                 --- = ((             }}

2(a),(c),ECI D D t where the following conditions are satisfied L 2(a),(c),ECI r 2(a),(c),ECI L 2(a),(c),ECI Eq. 4.3.5 0.7 ---- (( }} ---- (( }} 20 --- (( }} Eq. 4.3.6 D D t Eq. 4.3.7 Calculate geometry constants: 0.5D - r th := acos -------------------- = (( 2(a),(c),ECI L-r

                                                                                            }}                                            Eq. 4.3.8 Lt                                                      2(a),(c),ECI Eq. 4.3.9 th := -------------- = ((                                       }}

r 0.5D - r

                         ---------------------------------- + r if  th <  th                                                           Eq. 4.3.10 R th :=    cos      (  th -  th )

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Calculate coefficients: r r 9.31 ---- - 0.086 if ---- 0.08 Eq. 4.3.12 D D C 1 := r 0.692 ---- + 0.605 otherwise Eq. 4.3.13 D (( Eq. 4.3.14 Eq. 4.3.15 2(a),(c),ECI

}}

Calculate internal pressure expected to produce elastic buckling of the knuckle: 2 C1 ET t 2(a),(c),ECI P eth := ---------------------------------------------- = (( }} Eq. 4.3.16 R th C 2 R th ------- --r 2 Because the allowable stress at 600°F temperature is governed by time-independent properties, then 2(a),(c),ECI C 3 := S y = (( }} Calculate internal pressure that results in a maximum stress in the knuckle equal to the material yield strength: C3 t 2(a),(c),ECI P y := ------------------------------------------------ = (( }} R th Eq. 4.3.17 C 2 R th -------- - - 1 2 r Calculate internal pressure expected to result in a buckling failure of the knuckle: P eth 2(a),(c),ECI G := ---------- = (( }} Eq. 4.3.20 Py © Copyright 2022 by NuScale Power, LLC 112

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 0.6P eth if G 1 Eq. 4.3.18 P ck := 0.77508G - 0.20354G - 0.019274G - 2 3

                       -----------------------------------------------------------------------------------------------------------  P y otherwise                   Eq. 4.3.19 2                                      3 1 + 0.19014G - 0.089534G + 0.0093965G 2(a),(c),ECI P ck = ((                                   }}

((

                                                                                                                                                                   }}2(a),(c),ECI 4.4.2         Buckling of Containment Vessel Lower Head The internal pressure that results in buckling in the CNV lower head buckling is

(( }}2(a),(c),ECI psi. Equation numbers shown are references to the equation numbers in Section 4.3.6.1 of Section VIII, Division 2 (Reference 9). Containment Vessel Bottom Head - Knuckle Buckling under Internal Pressure Section 4.3.6.1 of Section VIII, Division 2, Torispherical Heads with the Same Crown and Knuckle Thicknesses. Material properties of SA-965 FXM19 at design temperature: 6 Modulus of Elasticity at 600 degrees F (Section II, Part D, Table E T := 25.3 x 10 psi TM-1) S y := 37400 psi Yield strength at 600 degrees F (Section II, Part D, Table Y-1, Page 628, Line 10) ((

                                                                                                                                                                   }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure 4-18 Torispherical Head Geometry Calculate geometry ratios: L- = ((

              ---                            }}

2(a),(c),ECI

                                                                       ---r- = ((            }}

2(a),(c),ECI L

                                                                                                               --- = ((             }}

2(a),(c),ECI D D t where the following conditions are satisfied: L r L Eq. 4.3.5 0.7 ---- 1.0 ---- 0.06 20 --- 2000 Eq. 4.3.6 D D t Eq. 4.3.7 Calculate geometry constants: 0.5D - r th := acos -------------------- = (( 2(a),(c),ECI

                                                                                         }}                                            Eq. 4.3.8 L-r Lt                                                   2(a),(c),ECI Eq. 4.3.9 th := -------------- = ((                                    }}

r 0.5D - r

                         ---------------------------------- + r if  th <  th                                                        Eq. 4.3.10 R th := cos (  th -  th )

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Calculate coefficients: r r 9.31 ---- - 0.086 if ---- 0.08 Eq. 4.3.12 D D C 1 := r 0.692 ---- + 0.605 otherwise Eq. 4.3.13 D 2(a),(c),ECI C 1 = (( }} r 1.25 if ---- 0.08 Eq. 4.3.14 D C 2 := r 1.46 - 2.6 ---- otherwise Eq. 4.3.15 D 2(a),(c),ECI C 2 = (( }} Calculate internal pressure expected to produce elastic buckling of the knuckle: 2 C1 ET t 2(a),(c),ECI P eth := ---------------------------------------------- = (( }} Eq. 4.3.16 R th C 2 R th ------- --r 2 Because the allowable stress at 600°F temperature is governed by time-independent properties, then: 2(a),(c),ECI C 3 := S y = (( }} Calculate internal pressure that results in a maximum stress in the knuckle equal to the material yield strength: C3 t 2(a),(c),ECI P y := ------------------------------------------------ = (( }} R th Eq. 4.3.17 C 2 R th -------- - - 1 2 r Calculate internal pressure expected to result in a buckling failure of the knuckle: P eth 2(a),(c),ECI G := ---------- = (( }} Eq. 4.3.20 Py © Copyright 2022 by NuScale Power, LLC 115

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 0.6P eth if G 1 Eq. 4.3.18 P ck := 0.77508G - 0.20354G - 0.019274G - 2 3

                      -----------------------------------------------------------------------------------------------------------  P y otherwise                   Eq. 4.3.19 2                                      3 1 + 0.19014G - 0.089534G + 0.0093965G 2(a),(c),ECI P ck = ((                               }}

((

                                                                                                                                                                  }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 5.0 Summary and Conclusions This report evaluates the CNV to determine an ultimate pressure capacity for a beyond design basis LOCA event. Multiple finite element models and analyses evaluate the bolted connections, shell regions away from concentrations, and buckling of the knuckle regions in the heads. The CNV ultimate pressure capacity is greater than (( }}2(a),(c),ECI. Failure is a result of a saddle-shaped deformation at the CNV manway port due to CNV shell pressure dilation that promotes gaps at the 12 oclock and 6 oclock locations of the manway port opening, which is the cause of the lower pressure capability in these locations. © Copyright 2022 by NuScale Power, LLC 117

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 6.0 References 1 U.S. Nuclear Regulatory Commission, Containment Structural Evaluation for Internal Pressure Loadings above Design-Basis Pressure, Regulatory Guide 1.216, Revision 0, August 2010. 2 U.S. Nuclear Regulatory Commission, Containment Integrity Research at Sandia National Laboratories - An Overview, NUREG/CR-6906, July 2006. 3 U.S. Nuclear Regulatory Commission, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition - Design of Structures, Components, Equipment, and Systems, NUREG-0800, Chapter 3, Section 3.8.2, Revision 3, May 2010. 4 U.S. Code of Federal Regulations, Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Facilities, Appendix B, Part 50, Chapter 1, Title 10, Energy, (10 CFR 50, Appendix B). 5 American Society of Mechanical Engineers, Quality Assurance Program Requirements for Nuclear Facility Applications, NQA-1-2008, NQA-1a-2009 Addenda. 6 American Society of Mechanical Engineers, Boiler and Pressure Vessel Code, 2017 Edition, no addenda, Section II, Materials, Part D, Properties (Customary), 2017. 7 American Society of Mechanical Engineers, Boiler and Pressure Vessel Code, 2017 Edition, no addenda, Section III, Rules for Construction of Nuclear Facility Components, Division 1 - Subsection NB, Class 1 Components, 2017. 8 American Society of Mechanical Engineers, Boiler and Pressure Vessel Code, 2017 Edition, no addenda, Section III, Rules for Construction of Nuclear Facility Components, 2017. 9 American Society of Mechanical Engineers, Boiler and Pressure Vessel Code, 2017 Edition, no addenda, Section VIII, Rules for Construction of Pressure Vessels, Division 2, Alternative Rules, 2017. 10 American Society of Mechanical Engineers, Unified Inch Screw Threads (UN and UNR Thread Form), ASME B1.1-2003, September 30, 2004. 11 Jones, F.D., et. al., Machinerys Handbook, 26th Edition, Industrial Press Inc., New York, New York, 2000. 12 Fundamentals of Heat and Mass Transfer, Incropera et al., Sixth Edition, John Wiley and Sons Inc., 2007. © Copyright 2022 by NuScale Power, LLC 118

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Appendix A Allowable O-Ring Springback Calculation This appendix provides the basis for the calculation of allowable O-ring springback values associated with useful elastic recovery of the seals using a conservative approach. After the O-rings seat and compress to the point where there is metal-to-metal contact between the flange and vessel mating surfaces (or flange-to-flange surfaces in the CNV closure flange), increasing the internal pressure beyond a certain point induces gaps between the mating surfaces, which relieves the seating forces on the O-rings. As they become unloaded, O-rings partially expand back toward their initial unloaded shape, though not fully, which is referred to as springback. Total springback is the total amount the O-rings spring back when fully unloaded. Useful elastic recovery is a portion of the total springback that maintains adequate sealing capability. The values in this appendix conservatively estimate the useful elastic recovery and are the allowable gap sizes between mating surfaces in the sealability evaluations. A.1 Inputs Seal vendors provide values for expected total springback of individual O-ring seals; however, maintaining a leak-tight seal at the closures depends on the useful elastic recovery of the O-ring seals. Figure A-1 displays the useful elastic recovery of the O-ring accounts for a partial percentage of the total springback. Data from seal vendors is used to calculate the allowable springback values for each seal. © Copyright 2022 by NuScale Power, LLC A-1

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Figure A-1 O-Ring Seal Springback Characteristic Curve A.2 Methodology The compressed width of the O-ring seals is based on the compression ratio, c, for each cover design,where c is the amount of compression of the seal in the fully seated configuration divided by the uncompressed height of the O-ring. w c = d + cd Equation A-1 where, wc = compressed width of the O-ring. d = the uncompressed diameter of the O-ring. c = compression ratio of the seal in the seated configuration. © Copyright 2022 by NuScale Power, LLC A-2

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 The linear compression force per linear inch of seal due to internal pressure is calculated. A conservative calculation assumes that the force distributes uniformly over the full width of the compressed seal (beyond seal contact at the apex point) and normal to the seal seating contact surfaces. Fl = Pi wc Equation A-2 where, P i = the internal pressure in psi. Using the vendor designated seating load (in pounds per circumferential inch) and the minimum total springback () from vendor catalogs, the useful elastic recovery value (e2) is based on the linear compression force applied, F l . F l --- 2 e 2 = --- - -------------- Equation A-3 2 Y2 where,

         = minimum total springback in inches.

Y 2 = seating load in pounds per circumferential inch. A.3 Results Table A-1 and Table A-2 show the input parameters and calculated allowable springback values for each seal, respectively. Table A-1 Parameters Used in Allowable Springback Calculations for Each Seal ((

                                                                                                   }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table A-2 Allowable Springback Values for Each Seal ((

                                                                                            }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table A-2 Allowable Springback Values for Each Seal (Continued) ((

                                                                                          }}2(a),(c),ECI

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Appendix B Nonlinear Stress-Strain Curves B.1 Inputs The input data used to generate the multilinear kinematic hardening nonlinear stress-strain curves are derived in accordance with ASME BPVC Section VIII Division II, Annex 3-D (Reference 9) with the first point (zero strain point) being at the minimum material yield strength listed in Section II, Part D of the ASME BPVC (Reference 6). The guidance of Reference 1, Section C.1.d specifies that the non-linear stress-strain curve be based on the ASME BPVC minimum yield strength, and the stress-strain beyond yield is representative of the specific grade. B.2 Nonlinear Stress-Strain Curves for ANSYS Material Property Input Table B-1 through Table B-15 contain the raw stress and strain data input into ANSYS for each material in this evaluation. The curves contain the plastic portion of the curve with the first point being 0 in/in strain at the ASME BPVC designated yield strength, Sy, at temperature. Table B-1 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 70 Degrees F Strain (in/in) Stress (psi) 0.000000 90000 0.003155 92000 0.004950 94000 0.007701 96000 0.011424 98000 0.015504 100000 0.019247 102000 0.022666 104000 0.026148 106000 0.029991 108000 0.034356 110000 0.039325 112000 0.044962 114000 0.051328 116000 0.058486 118000 0.066513 120000 0.075490 122000 0.085507 124000 0.096665 126000 0.109069 128000 0.122834 130000 0.130266 131000 0.300000 131000 © Copyright 2022 by NuScale Power, LLC B-1

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-2 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 140 Degrees F Strain (in/in) Stress (psi) 0.000000 88160 0.002990 90000 0.004561 92000 0.006936 94000 0.010277 96000 0.014320 98000 0.018402 100000 0.022129 102000 0.025653 104000 0.029296 106000 0.033295 108000 0.037784 110000 0.042840 112000 0.048521 114000 0.054875 116000 0.061963 118000 0.069839 120000 0.078575 122000 0.088241 124000 0.098917 126000 0.110689 128000 0.123646 130000 0.140141 132300 0.300000 132300 © Copyright 2022 by NuScale Power, LLC B-2

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-3 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 500 Degrees F Strain (in/in) Stress (psi) 0.000000 80800 0.002610 82000 0.003893 84000 0.005811 86000 0.008591 88000 0.012310 90000 0.016666 92000 0.021077 94000 0.025197 96000 0.029113 98000 0.033094 100000 0.037371 102000 0.042094 104000 0.047349 106000 0.053198 108000 0.059690 110000 0.066873 112000 0.074797 114000 0.083515 116000 0.093088 118000 0.103576 120000 0.115048 122000 0.127576 124000 0.141238 126000 0.156889 128100 0.300000 128100 © Copyright 2022 by NuScale Power, LLC B-3

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-4 Nonlinear Stress-Strain Curve - SA-336/182 F6NM at 600 Degrees F Strain (in/in) Stress (psi) 0.000000 78500 0.002823 80000 0.004339 82000 0.006661 84000 0.010024 86000 0.014320 88000 0.018925 90000 0.023255 92000 0.027295 94000 0.031359 96000 0.035744 98000 0.040631 100000 0.046125 102000 0.052294 104000 0.059200 106000 0.066900 108000 0.075457 110000 0.084941 112000 0.095429 114000 0.107000 116000 0.119744 118000 0.133755 120000 0.151567 122300 0.300000 122300 © Copyright 2022 by NuScale Power, LLC B-4

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-5 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 70 Degrees F Strain (in/in) Stress (psi) 0.000000 55000 0.002713 56000 0.003739 58000 0.005160 60000 0.007135 62000 0.009863 64000 0.013561 66000 0.018401 68000 0.024405 70000 0.031356 72000 0.038828 74000 0.046341 76000 0.053550 78000 0.060319 80000 0.066692 82000 0.072794 84000 0.078768 86000 0.084739 88000 0.090802 90000 0.097025 92000 0.103454 94000 0.110121 96000 0.117048 98000 0.124251 100000 0.131739 102000 0.139522 104000 0.147607 106000 0.155999 108000 0.164703 110000 0.173727 112000 0.183074 114000 0.192750 116000 0.202760 118000 0.213110 120000 0.223805 122000 0.234851 124000 0.246251 126000 0.258013 128000 0.270142 130000 0.282642 132000 0.295520 134000 0.308782 136000 0.322430 138000 © Copyright 2022 by NuScale Power, LLC B-5

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-5 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 70 Degrees F (Continued) Strain (in/in) Stress (psi) 0.336474 140000 0.337186 140100 0.600000 140100 © Copyright 2022 by NuScale Power, LLC B-6

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-6 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 140 Degrees F Strain (in/in) Stress (psi) 0.000000 50840 0.002781 52000 0.003789 54000 0.005173 56000 0.007074 58000 0.009682 60000 0.013199 62000 0.017803 64000 0.023546 66000 0.030281 68000 0.037647 70000 0.045190 72000 0.052532 74000 0.059474 76000 0.065998 78000 0.072192 80000 0.078184 82000 0.084094 84000 0.090025 86000 0.096049 88000 0.102221 90000 0.108576 92000 0.115141 94000 0.121930 96000 0.128957 98000 0.136232 100000 0.143759 102000 0.151543 104000 0.159591 106000 0.167906 108000 0.176490 110000 0.185346 112000 0.194482 114000 0.203896 116000 0.213595 118000 0.223581 120000 0.233858 122000 0.244428 124000 0.255296 126000 0.266464 128000 0.277937 130000 0.289718 132000 0.301809 134000 0.314214 136000 0.326938 138000 © Copyright 2022 by NuScale Power, LLC B-7

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-6 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 140 Degrees F (Continued) Strain (in/in) Stress (psi) 0.339982 140000 0.353351 142000 0.367740 144100 0.600000 144100 © Copyright 2022 by NuScale Power, LLC B-8

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-7 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 500 Degrees F Strain (in/in) Stress (psi) 0.000000 38800 0.002851 40000 0.003984 42000 0.005589 44000 0.007876 46000 0.011114 48000 0.015587 50000 0.021470 52000 0.028672 54000 0.036770 56000 0.045144 58000 0.053260 60000 0.060856 62000 0.067922 64000 0.074590 66000 0.081026 68000 0.087376 70000 0.093754 72000 0.100237 74000 0.106875 76000 0.113705 78000 0.120748 80000 0.128016 82000 0.135521 84000 0.143269 86000 0.151264 88000 0.159508 90000 0.168006 92000 0.176758 94000 0.185768 96000 0.195039 98000 0.204570 100000 0.214365 102000 0.224424 104000 0.234750 106000 0.245346 108000 0.256213 110000 0.267351 112000 0.278764 114000 0.290453 116000 0.302420 118000 0.314666 120000 0.327193 122000 0.340004 124000 0.353098 126000 © Copyright 2022 by NuScale Power, LLC B-9

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-7 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 500 Degrees F (Continued) Strain (in/in) Stress (psi) 0.366479 128000 0.380147 130000 0.394105 132000 0.408354 134000 0.423631 136100 0.600000 136100 © Copyright 2022 by NuScale Power, LLC B-10

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-8 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 600 Degrees F Strain (in/in) Stress (psi) 0.000000 37400 0.002583 38000 0.003624 40000 0.005105 42000 0.007227 44000 0.010265 46000 0.014519 48000 0.020216 50000 0.027322 52000 0.035445 54000 0.043939 56000 0.052220 58000 0.059970 60000 0.067162 62000 0.073926 64000 0.080435 66000 0.086846 68000 0.093278 70000 0.099811 72000 0.106502 74000 0.113383 76000 0.120477 78000 0.127799 80000 0.135359 82000 0.143162 84000 0.151212 86000 0.159513 88000 0.168066 90000 0.176876 92000 0.185943 94000 0.195270 96000 0.204857 98000 0.214707 100000 0.224822 102000 0.235204 104000 0.245853 106000 0.256771 108000 0.267961 110000 0.279424 112000 0.291161 114000 0.303174 116000 0.315464 118000 0.328034 120000 0.340885 122000 0.354017 124000 © Copyright 2022 by NuScale Power, LLC B-11

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-8 Nonlinear Stress-Strain Curve - SA-965 FXM-19 at 600 Degrees F (Continued) Strain (in/in) Stress (psi) 0.367433 126000 0.381134 128000 0.395122 130000 0.409398 132000 0.429870 134800 0.600000 134800 © Copyright 2022 by NuScale Power, LLC B-12

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-9 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 70 Degrees F Strain (in/in) Stress (psi) 0.000000 150000 0.005790 154000 0.009204 156000 0.014575 158000 0.022103 160000 0.030940 162000 0.039447 164000 0.046458 166000 0.051881 168000 0.056202 170000 0.059926 172000 0.063399 174000 0.066818 176000 0.070284 178000 0.073848 180000 0.077537 182000 0.081363 184000 0.085333 186000 0.089454 188000 0.093729 190000 0.098162 192000 0.102756 194000 0.107515 196000 0.112445 198000 0.117547 200000 0.122827 202000 0.128287 204000 0.133935 206000 0.139773 208000 0.145806 210000 0.152038 212000 0.158475 214000 0.165120 216000 0.171979 218000 0.179056 220000 0.186357 222000 0.193885 224000 0.201647 226000 0.209647 228000 0.217890 230000 0.226382 232000 0.300000 232000 © Copyright 2022 by NuScale Power, LLC B-13

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-10 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 140 Degrees F Strain (in/in) Stress (psi) 0.000000 147600 0.002680 148000 0.004092 150000 0.006450 152000 0.010352 154000 0.016396 156000 0.024550 158000 0.033607 160000 0.041856 162000 0.048423 164000 0.053488 166000 0.057611 168000 0.061270 170000 0.064761 172000 0.068246 174000 0.071806 176000 0.075481 178000 0.079292 180000 0.083248 182000 0.087358 184000 0.091625 186000 0.096051 188000 0.100644 190000 0.105405 192000 0.110340 194000 0.115451 196000 0.120745 198000 0.126223 200000 0.131893 202000 0.137758 204000 0.143822 206000 0.150091 208000 0.156570 210000 0.163262 212000 0.170174 214000 0.177310 216000 0.184675 218000 0.192274 220000 0.200114 222000 0.208198 224000 0.216533 226000 0.226434 228300 0.300000 228300 © Copyright 2022 by NuScale Power, LLC B-14

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-11 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 500 Degrees F Strain (in/in) Stress (psi) 0.000000 136800 0.003225 138000 0.005181 140000 0.008585 142000 0.014237 144000 0.022474 146000 0.032192 148000 0.041262 150000 0.048423 152000 0.053842 154000 0.058210 156000 0.062104 158000 0.065857 160000 0.069639 162000 0.073531 164000 0.077570 166000 0.081774 168000 0.086153 170000 0.090713 172000 0.095460 174000 0.100398 176000 0.105533 178000 0.110870 180000 0.116413 182000 0.122169 184000 0.128141 186000 0.134338 188000 0.140765 190000 0.147426 192000 0.154329 194000 0.161480 196000 0.168884 198000 0.176548 200000 0.184478 202000 0.192681 204000 0.201163 206000 0.209932 208000 0.218993 210000 0.226457 211600 0.300000 211600 © Copyright 2022 by NuScale Power, LLC B-15

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-12 Nonlinear Stress-Strain Curve - SB-637 UNS N07718 at 600 Degrees F Strain (in/in) Stress (psi) 0.000000 135300 0.002887 136000 0.004619 138000 0.007655 140000 0.012812 142000 0.020632 144000 0.030324 146000 0.039759 148000 0.047356 150000 0.053076 152000 0.057611 154000 0.061591 156000 0.065391 158000 0.069207 160000 0.073128 162000 0.077195 164000 0.081431 166000 0.085846 168000 0.090445 170000 0.095235 172000 0.100219 174000 0.105405 176000 0.110797 178000 0.116400 180000 0.122221 182000 0.128263 184000 0.134534 186000 0.141041 188000 0.147788 190000 0.154782 192000 0.162029 194000 0.169536 196000 0.177310 198000 0.185356 200000 0.193682 202000 0.202294 204000 0.211200 206000 0.220405 208000 0.226554 209300 0.300000 209300 © Copyright 2022 by NuScale Power, LLC B-16

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-13 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 70 Degrees F Strain (in/in) Stress (psi) 0.000000 30000 0.005173 34000 0.007798 36000 0.011804 38000 0.017668 40000 0.025550 42000 0.034952 44000 0.044842 46000 0.054297 48000 0.062950 50000 0.070898 52000 0.078414 54000 0.085760 56000 0.093125 58000 0.100630 60000 0.108351 62000 0.116329 64000 0.124590 66000 0.133149 68000 0.142013 70000 0.151190 72000 0.160682 74000 0.170492 76000 0.180623 78000 0.191076 80000 0.201854 82000 0.212957 84000 0.224389 86000 0.236150 88000 0.248242 90000 0.260668 92000 0.273428 94000 0.286525 96000 0.299959 98000 0.313733 100000 0.327847 102000 0.342304 104000 0.357104 106000 0.372250 108000 0.387743 110000 0.403583 112000 0.419773 114000 0.436314 116000 0.449801 117600 0.600000 117600 © Copyright 2022 by NuScale Power, LLC B-17

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-14 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 140 Degrees F Strain (in/in) Stress (psi) 0.000000 27360 0.002648 28000 0.003984 30000 0.006057 32000 0.009311 34000 0.014315 36000 0.021480 38000 0.030583 40000 0.040616 42000 0.050408 44000 0.059355 46000 0.067473 48000 0.075053 50000 0.082396 52000 0.089719 54000 0.097163 56000 0.104808 58000 0.112700 60000 0.120866 62000 0.129319 64000 0.138067 66000 0.147115 68000 0.156466 70000 0.166123 72000 0.176085 74000 0.186356 76000 0.196934 78000 0.207824 80000 0.219023 82000 0.230534 84000 0.242359 86000 0.254496 88000 0.266949 90000 0.279717 92000 0.292801 94000 0.306202 96000 0.319922 98000 0.333960 100000 0.348318 102000 0.362996 104000 0.377996 106000 0.393317 108000 0.408961 110000 0.424929 112000 © Copyright 2022 by NuScale Power, LLC B-18

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-14 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 140 Degrees F (Continued) Strain (in/in) Stress (psi) 0.441221 114000 0.457838 116000 0.470514 117500 0.600000 117500 © Copyright 2022 by NuScale Power, LLC B-19

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-15 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 650 Degrees F Strain (in/in) Stress (psi) 0.000000 18000 0.003792 20000 0.006512 22000 0.011550 24000 0.019970 26000 0.031069 28000 0.042282 30000 0.052011 32000 0.060434 34000 0.068234 36000 0.075902 38000 0.083695 40000 0.091732 42000 0.100063 44000 0.108711 46000 0.117681 48000 0.126977 50000 0.136598 52000 0.146542 54000 0.156809 56000 0.167397 58000 0.178304 60000 0.189529 62000 0.201071 64000 0.212928 66000 0.225099 68000 0.237582 70000 0.250377 72000 0.263482 74000 0.276895 76000 0.290617 78000 0.304645 80000 0.318978 82000 0.333616 84000 0.348558 86000 0.363802 88000 0.379348 90000 0.395194 92000 0.411341 94000 0.427786 96000 0.444529 98000 0.461569 100000 0.478906 102000 0.496538 104000 © Copyright 2022 by NuScale Power, LLC B-20

Containment Vessel Ultimate Pressure Integrity TR-121516-NP Revision 0 Table B-15 Nonlinear Stress-Strain Curve - SA-479 Type 304 at 650 Degrees F (Continued) (Continued) Strain (in/in) Stress (psi) 0.514465 106000 0.537286 108500 0.600000 108500 © Copyright 2022 by NuScale Power, LLC B-21

LO-133412 : Affidavit of Carrie Fosaaen, AF-133413 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

NuScale Power, LLC AFFIDAVIT of Carrie Fosaaen I, Carrie Fosaaen, state as follows: (1) I am the Senior Director of Regulatory Affairs of NuScale Power, LLC (NuScale), and as such, I have been specifically delegated the function of reviewing the information described in this Affidavit that NuScale seeks to have withheld from public disclosure, and am authorized to apply for its withholding on behalf of NuScale (2) I am knowledgeable of the criteria and procedures used by NuScale in designating information as a trade secret, privileged, or as confidential commercial or financial information. This request to withhold information from public disclosure is driven by one or more of the following: (a) The information requested to be withheld reveals distinguishing aspects of a process (or component, structure, tool, method, etc.) whose use by NuScale competitors, without a license from NuScale, would constitute a competitive economic disadvantage to NuScale. (b) The information requested to be withheld consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), and the application of the data secures a competitive economic advantage, as described more fully in paragraph 3 of this Affidavit. (c) Use by a competitor of the information requested to be withheld would reduce the competitors expenditure of resources, or improve its competitive position, in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product. (d) The information requested to be withheld reveals cost or price information, production capabilities, budget levels, or commercial strategies of NuScale. (e) The information requested to be withheld consists of patentable ideas. (3) Public disclosure of the information sought to be withheld is likely to cause substantial harm to NuScales competitive position and foreclose or reduce the availability of profit-making opportunities. The accompanying report reveals distinguishing aspects about the process by which NuScale develops its CNV Ultimate Pressure Integrity. NuScale has performed significant research and evaluation to develop a basis for this process and has invested significant resources, including the expenditure of a considerable sum of money. The precise financial value of the information is difficult to quantify, but it is a key element of the design basis for a NuScale plant and, therefore, has substantial value to NuScale. If the information were disclosed to the public, NuScale's competitors would have access to the information without purchasing the right to use it or having been required to undertake a similar expenditure of resources. Such disclosure would constitute a misappropriation of NuScale's intellectual property, and would deprive NuScale of the opportunity to exercise its competitive advantage to seek an adequate return on its investment. (4) The information sought to be withheld is in the enclosed report entitled CNV Ultimate Pressure Integrity.The enclosure contains the designation Proprietary" at the top of each page containing proprietary information. The information considered by NuScale to be proprietary is identified within double braces, "(( }}" in the document. (5) The basis for proposing that the information be withheld is that NuScale treats the information as a trade secret, privileged, or as confidential commercial or financial information. NuScale relies upon the exemption from disclosure set forth in the Freedom of Information Act ("FOIA"), 5 USC § AF-133413 Page 1 of 2

552(b)(4), as well as exemptions applicable to the NRC under 10 CFR §§ 2.390(a)(4) and 9.17(a)(4). (6) Pursuant to the provisions set forth in 10 CFR § 2.390(b)(4), the following is provided for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld: (a) The information sought to be withheld is owned and has been held in confidence by NuScale. (b) The information is of a sort customarily held in confidence by NuScale and, to the best of my knowledge and belief, consistently has been held in confidence by NuScale. The procedure for approval of external release of such information typically requires review by the staff manager, project manager, chief technology officer or other equivalent authority, or the manager of the cognizant marketing function (or his delegate), for technical content, competitive effect, and determination of the accuracy of the proprietary designation. Disclosures outside NuScale are limited to regulatory bodies, customers and potential customers and their agents, suppliers, licensees, and others with a legitimate need for the information, and then only in accordance with appropriate regulatory provisions or contractual agreements to maintain confidentiality. (c) The information is being transmitted to and received by the NRC in confidence. (d) No public disclosure of the information has been made, and it is not available in public sources. All disclosures to third parties, including any required transmittals to NRC, have been made, or must be made, pursuant to regulatory provisions or contractual agreements that provide for maintenance of the information in confidence. (e) Public disclosure of the information is likely to cause substantial harm to the competitive position of NuScale, taking into account the value of the information to NuScale, the amount of effort and money expended by NuScale in developing the information, and the difficulty others would have in acquiring or duplicating the information. The information sought to be withheld is part of NuScale's technology that provides NuScale with a competitive advantage over other firms in the industry. NuScale has invested significant human and financial capital in developing this technology and NuScale believes it would be difficult for others to duplicate the technology without access to the information sought to be withheld. I declare under penalty of perjury that the foregoing is true and correct. Executed on 12/31/2022. Carrie Fosaaen AF-133413 Page 2 of 2}}

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