ML24213A316

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LLC, Submittal of NuScale Technical Report, NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856, Revision 0
ML24213A316
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Site: 05200050
Issue date: 07/31/2024
From: Fosaaen C
NuScale
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Office of Nuclear Reactor Regulation, Document Control Desk
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LO-172648 TR-169856, Rev 0
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LO-172648 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com July 31, 2024 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 NuScale Technical Report, NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856, Revision 0 NuScale Power, LLC (NuScale) hereby submits Revision 0 of the technical report NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, (TR-169856). The purpose of this submittal is to request that the NRC review and approve the uncertainties utilized in the NuScale US460 statistical subchannel critical heat flux analysis that supports NRC review of FSAR Chapter 4. contains the proprietary version of the report entitled NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856, Revision 0.

NuScale requests that the proprietary version be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390. The enclosed affidavits (Enclosure 3 and Enclosure 4) support this request. Enclosure 3 pertains to the NuScale proprietary information, denoted by double braces (i.e., ((). Enclosure 4 pertains to the Framatome Inc. (formerly AREVA Inc.) proprietary information, denoted by bold brackets (i.e., [ ]). contains the nonproprietary version of the report. This letter makes no regulatory commitments and no revisions to any existing regulatory commitments. If you have any questions, please contact Amanda Bode at 541-452-7971 or at abode@nuscalepower.com. I declare under penalty of perjury that the foregoing is true and correct. Executed on July 31, 2024. Sincerely, Carrie Fosaaen Vice President, Regulatory Affairs NuScale Power, LLC

LO-172648 Page 2 of 2 07/31/2024 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Distribution: Mahmoud Jardaneh, Chief New Reactor Licensing Branch, NRC Getachew Tesfaye, Senior Project Manager, NRC Stacy Joseph, Senior Project Manager, NRC Ricky Vivanco, Project Manager, NRC : NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856-P, Revision 0, proprietary version : NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856-NP, Revision 0, nonproprietary version : Affidavit of Carrie Fosaaen, AF-172649 : Affidavit of Morris Byram, Framatome

LO-172648 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com : NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856-P, Revision 0, proprietary version

LO-172648 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, TR-169856-NP, Revision 0, nonproprietary version

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 Licensing Technical Report © Copyright 2024 by NuScale Power, LLC i NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties July 2024 Revision 0 Docket: 52-050 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 www.nuscalepower.com © Copyright 2024 by NuScale Power, LLC

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 Licensing Technical Report © Copyright 2024 by NuScale Power, LLC ii REVISION HISTORY Revision Date Notes 0 July 2024 Initial Issuance

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 Licensing Technical Report © Copyright 2024 by NuScale Power, LLC iii 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.

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 Licensing Technical Report © Copyright 2024 by NuScale Power, LLC iv Department of Energy Acknowledgment 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.

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 Table of Contents © Copyright 2024 by NuScale Power, LLC v Abstract................................................................... 1 Executive Summary.......................................................... 2 1.0 Introduction.......................................................... 3 1.1 Purpose.............................................................. 3 1.2 Scope................................................................ 3 1.3 Abbreviations and Definitions.............................................. 4 2.0 Background.......................................................... 5 2.1 Regulatory Requirements................................................ 5 3.0 Submodel Parameter Uncertainty and Distribution.......................... 6 3.1 Core Bypass Flow Fraction............................................... 7 3.2 Enthalpy Rise Engineering Uncertainty...................................... 8 3.3 Heat Flux Engineering Uncertainty........................................ 10 3.4 Fuel Rod Bow Uncertainty............................................... 11 3.5 NSP4 Correlation Uncertainty............................................ 12 3.6 Statistical Distributions.................................................. 13 4.0 Conclusion.......................................................... 14 5.0 References.......................................................... 14

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 List of Tables © Copyright 2024 by NuScale Power, LLC vi Table 1-1 Abbreviations.................................................... 4 Table 1-2 Definitions....................................................... 4 Table 2-1 Guidance on Fulfilling Condition and Limitation #2 of Reference 5.1.......... 5 Table 3-1 Sample Distributions............................................. 13

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 List of Figures © Copyright 2024 by NuScale Power, LLC vii Figure 3-1 Sampled Core Bypass Flow Probability Density Function (left) and Cumulative Distribution Function (right)................................ 7 Figure 3-2 Sampled Flow Area Reduction Hot Channel Factor Probability Density Function (left) and Cumulative Distribution Function (right).......... 8 Figure 3-3 Sampled Flow Area Reduction Hot Channel Factor Probability Density Function (left) and Cumulative Distribution Function (right).......... 9 Figure 3-4 Sampled Heat Flux Engineering Uncertainty Probability Density Function (left) and Cumulative Distribution Function (right)......... 10 Figure 3-5 Sampled Fuel Rod Bow Uncertainty Probability Density Function (left) and Cumulative Distribution Function (right)................ 11 Figure 3-6 Sample Critical Heat Flux Ratio Predicted-to-Measured Ratio Probability Density Function (left) and Cumulative Distribution Function (right)......... 12

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 1 Abstract TR-169856-P, NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties provides the statistical uncertainties and penalties used to calculate the statistical critical heat flux analysis limit using the methodology approved in TR-108601-P-A, Revision 4, Statistical Subchannel Analysis Methodology (Reference 5.1). The statistical critical heat flux analysis limit supports critical heat flux margin calculations for use in safety analysis applications in Final Safety Analysis Report Chapter 4 and Chapter 15. A single critical heat flux analysis limit, appropriate for a wide range of conditions, is determined using the probabilistic uncertainties noted in the report and protects against critical heat flux violations with a 95 percent probability at a 95 percent confidence level with the use of the approved NuScale NSP4 critical heat flux correlation. Section 3.0 of this report provides the information required to satisfy the condition and limitation #2 defined in the Final Safety Evaluation Report for TR-108601-P-A (Reference 5.1).

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 2 Executive Summary TR-169856-P, NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties provides the probabilistic uncertainties used to calculate the statistical critical heat flux analysis limit for safety analysis applications of the NuScale Power Plant US460 standard design. The statistical critical heat flux analysis is performed using the approved methodology in TR-108601-P-A (Reference 5.1.) Provisions of condition and limitation #2 of TR-108601-P-A Final Safety Evaluation Report (Reference 5.1) are met using the probabilistic uncertainties and values presented in this report.

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 3 1.0 Introduction 1.1 Purpose Technical report TR-169856-P, "NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties" provides the NuScale Power Plant US460 standard design calculation probabilistic uncertainties for use in the statistical critical heat flux analysis limit (SCHFAL) for safety analysis applications using the methodology in Statistical Subchannel Analysis Methodology, TR-108601-P-A, Revision 4, (Reference 5.1). The probabilistic uncertainties described in Section 3.0 are incorporated into the SCHFAL probabilistically to ensure protection of the nuclear fuel from failure due to critical heat flux (CHF) limit violations. A single SCHFAL value is determined that is applicable for a wide range of thermal-hydraulic conditions (i.e., pressure or temperature) and precludes CHF violations with a 95 percent probability at a 95 percent confidence level (95/95) with the approved NSP4 critical heat flux correlation and design limit (Reference 5.2). This report fulfills the requirements set forth in condition and limitation #2 of Reference 5.1. 1.2 Scope TR-169856-P provides a description of the uncertainties treated probabilistically in the methodology described in Reference 5.1 to calculate a statistical critical heat flux analysis limit. Parameters treated deterministically are not within the scope of this report. The approved NSP4 critical heat flux correlation as discussed in Reference 5.2 design limit is statistically combined with parameter uncertainties to determine the critical heat flux analysis limit that is used in safety analysis margin calculations reported in Final Safety Analysis Report (FSAR) Chapter 4 and Chapter 15 for the NuScale Power Plant US460 standard design. The statistical subchannel analysis methodology discussed in Reference 5.1 utilized to perform steady-state and transient subchannel analysis for design basis accidents is outside the scope of this report. Additionally, the NSP4 critical heat flux correlation discussed in Reference 5.2 is outside the scope of this report. The applicability domain for the US460 SCHFAL is defined in FSAR Table 4.4-8, Statistical Subchannel Analysis Limit Range of Applicability.

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 4 1.3 Abbreviations and Definitions Table 1-1 Abbreviations Term Definition CDF cumulative distribution function CHF critical heat flux FSAR Final Safety Evaluation Report Enthalpy rise engineering factor Average pin power hot channel factor Flow area hot channel factor Local heat flux hot channel factor Fuel rod bow uncertainty Core inlet flow HCF hot channel factor Owen Factor PDF probability density function P/M predicted-to-measured ratio SCHFAL statistical critical heat flux analysis limit 95/95 95 percent probability at a 95 percent confidence level Table 1-2 Definitions Term Definition Deterministic model Applies uncertainties for each parameter in a manner that is conservative without regard for the nature of the uncertainties Penalty An uncertainty value that is always more conservative than the nominal value Probabilistic model Applies uncertainties for each parameter in a random fashion within a chosen distribution. Several iterations of the model are used to obtain data for statistical assessment Uncertainty A value that can be either more or less conservative than the nominal value F E H F E H1 F E H2 FE Q F RB H Gin k

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 5 2.0

Background

TR-169856-P supports NuScale Power Plant US460 standard design FSAR Section 4.4, Thermal and Hydraulic Design and provides the information to satisfy the condition and limitation #2 of Reference 5.1. 2.1 Regulatory Requirements The regulatory requirement pertaining to the SCHFAL is General Design Criterion 10 of 10 CFR Part 50, Appendix A (Reference 5.4), as it relates to the margin required to ensure that fuel design limits specified in FSAR Chapter 4 are not exceeded. TR-169856-P fulfills the requirements of condition and limitation #2 of Reference 5.1. The condition and limitation requires the review and approval of the probabilistic uncertainties used to calculate the SCHFAL. A summary of the condition and limitation requirements and where each item is addressed is in Table 2-1, Guidance on Fulfilling Condition and Limitation #2 of Reference 5.1. Table 2-1 Guidance on Fulfilling Condition and Limitation #2 of Reference 5.1 Condition and Limitation Subpart (Reference 5.1) Summarized Condition and Limitation Treatments of Uncertainties in the US460 Design TR-169856-P Section 2a The maximum hot rod radial peaking analysis limit, including measurement uncertainties. Deterministic N/A1 2b The models and values used to determine the core thermal power. Deterministic N/A1 2c The models and values used to determine the core inlet flow. Deterministic2 N/A1 2d The models and values used to determine the core inlet temperature. Deterministic N/A1 2e The models and values used to determine the core exit pressure. Deterministic N/A1 2f The models and values used to determine the enthalpy rise measurement uncertainty. Deterministic N/A3 2g The models and values used to determine the enthalpy rise engineering uncertainties. Probabilistic Section 3.2 2h The models and values used to determine the heat flux engineering uncertainty. Probabilistic Section 3.3 2i The models and values used to determine the fuel rod bow uncertainty. Probabilistic Section 3.4 1 Deterministic parameters are built into the VIPRE-01 model (Reference 5.1, Section 3.13.2) 2 Core bypass flow fraction is treated statistically in Section 3.1. 3 The enthalpy rise measurement uncertainty is included in the maximum hot rod radial peaking analysis limit (Reference 5.1, Section 3.10.3)

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 6 3.0 Submodel Parameter Uncertainty and Distribution The methodology described in Reference 5.1 provides the framework for creating a SCHFAL that incorporates uncertainties related to core protection probabilistically. However, not all uncertainties for the US460 SCHFAL are treated probabilistically and these are accounted for elsewhere, either in boundary conditions to the VIPRE-01 evaluation model or deterministically in the VIPRE-01 evaluation model. The parameters and uncertainties that are deterministically accounted for or are in bounding modeling methods include:

NRELAP5 boundary conditions pressure dead band and uncertainty temperature dead band and uncertainty power measurement uncertainty bounding flow condition

VIPRE-01 evaluation methodology bounding radial peaking distribution bounding axial power distribution bounding inlet flow distribution The following uncertainties and penalties are treated statistically:

core flow bypass fraction

enthalpy rise engineering uncertainty

heat flux engineering uncertainty

fuel rod bow uncertainty

CHF correlation uncertainty

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 7 3.1 Core Bypass Flow Fraction The core bypass flow fraction decreases the amount of flow available to cool the core. The core inlet flow ( ) is defined in Section 3.12.2.2 of Reference 5.1. Flow conditions supplied as boundary conditions cover the system flow and flow measurement uncertainty, but the core bypass is covered probabilistically. ((

}}2(a),(c). ((
}}2(a),(c). Because this is range is deterministically bounding for the applicability domain (FSAR Table 4.4-8) and there is not an indication that a particular value is more probable than another value, a uniform distribution is used for the core bypass fraction.

(( }}2(a),(c). The resulting sampled probability density function (PDF) and cumulative distribution function (CDF) are provided in Figure 3-1, Sampled Core Bypass Flow Probability Function (left) and Cumulative Distribution Function (right). Figure 3-1 Sampled Core Bypass Flow Probability Density Function (left) and Cumulative Distribution Function (right) (( }}2(a),(c) Gin

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 8 3.2 Enthalpy Rise Engineering Uncertainty The enthalpy rise engineering factor ( ) is applied to the hot channel accounts for uncertainties related to manufacturing tolerances described in Reference 5.1, Section 3.12.4. The enthalpy rise engineering factor consists of the average pin power hot channel factor (HCF) ( ) that captures rod power effects, and the flow area reduction HCF ( ) that captures flow area effects on enthalpy rise. [ ]. An Owen factor (k) of 1.645 for a 95/95 one-sided tolerance limit is utilized (Table T-11b of Reference 5.3). ((

}}2(a),(c). ((
}}2(a),(c). The resulting sampled PDF and CDF are provided in Figure 3-2, Sampled Flow Reduction Hot Channel Factor Probability Density Function (left) and Cumulative Distribution Function (right).

For the flow area reduction HCF, the geometry uncertainties (e.g., rod pitch, rod outer diameter) have propagated impacts on the local enthalpy and lateral crossflow characteristics. The Figure 3-2 Sampled Flow Area Reduction Hot Channel Factor Probability Density Function (left) and Cumulative Distribution Function (right) [ ] F E H F E H1 F E H2

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 9 resulting distribution is not numerically normal but is more peaked than a standard normal distribution; thus, treating the distribution as normal is conservative due to the application of high penalty factors. (( }}2(a),(c) A k of 1.645 for a 95/95 one-sided tolerance limit is utilized as discussed in Table T-11b NUREG-1475, "Applying Statistics" (of Reference 5.3). (( }}2(a),(c). ((

}}2(a),(c). The resulting sampled PDF and CDF are provided in Figure 3-3, Sampled Flow Area Reduction Hot Channel Probability Density Function (left) and Cumulative Distribution Function (right).

Figure 3-3 Sampled Flow Area Reduction Hot Channel Factor Probability Density Function (left) and Cumulative Distribution Function (right) (( }}2(a),(c)

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 10 3.3 Heat Flux Engineering Uncertainty The local heat flux engineering uncertainty ( ) penalizes the local heat flux on the hot rod but does not affect the enthalpy rise along a channel. Input of into the SCHFAL is described in Reference 5.1, Section 3.12.5. [ ]. The local heat flux engineering uncertainty is provided by the fuel vendor. The local heat flux engineering uncertainty is treated as a one-sided normal (half-normal) distribution for conservatism (i.e., it only provides a penalty). ((

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

((

}}2(a),(c). The resulting sampled PDF and CDF are provided in Figure 3-4, Sampled Heat Flux Engineering Uncertainty Probability Density Function (left) and Cumulative Distribution Function (right).

Figure 3-4 Sampled Heat Flux Engineering Uncertainty Probability Density Function (left) and Cumulative Distribution Function (right) [ ] FE Q FE Q

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 11 3.4 Fuel Rod Bow Uncertainty The fuel rod bow uncertainty is a penalty that affects CHF because of flow area reduction in the hot channel due to closure. The fuel rod bow uncertainty is incorporated into the SCHFAL as discussed in Reference 5.1 Section 3.12.8.1. The fuel rod bow uncertainty ( ) is a conservative value utilizing the maximum allowed assembly exposure. ((

}}2(a),(c). Rods with high burnup do not experience high heat fluxes, so the CHF is less limiting. ((

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

}}2(a),(c). The resulting sampled PDF and CDF are provided in Figure 3-5, Sampled Fuel Rod Bow Uncertainty Probability Density Function (left) and Cumulative Distribution Function (right).

Figure 3-5 Sampled Fuel Rod Bow Uncertainty Probability Density Function (left) and Cumulative Distribution Function (right) (( }}2(a),(c) F RB H

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 12 3.5 NSP4 Correlation Uncertainty (( }}2(a),(c) A k of 1.645 for a one-sided tolerance limit is utilized (Table T-11a of Reference 5.3). The resulting sample standard deviation for the NSP4 CHF correlation is 0.127. (( }}2(a),(c) The resulting sampled PDF and CDF are provided in Figure 3-6, Sample Critical Heat Flux Ration Predicted-to-Measured Ratio Probability Density Function (left) and Cumulative Distribution Function (right). The sampled CDF, as designed, is skewed higher and provides a higher 95/95 value relative to the underlying data. Note 1: The blue line is the original data and the black line is the biased distribution. Figure 3-6 Sample Critical Heat Flux Ratio Predicted-to-Measured Ratio Probability Density Function (left) and Cumulative Distribution Function (right1) (( }}2(a),(c)

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 13 3.6 Statistical Distributions Sample distributions for the parameters considered in the US460 SCHFAL are summarized in Table 3-1, Sample Distributions. Table 3-1 Sample Distributions Parameter Distribution Power level Deterministic Core exit pressure Deterministic Core inlet mass flow rate Deterministic Core inlet temperature Deterministic Core bypass fraction (( }}2(a),(c) Pin power enthalpy rise HCF ( ) (( }}2(a),(c) Flow area reduction HCF ( ) (( }}2(a),(c) Local heat flux engineering factor ( ) (( }}2(a),(c) Fuel rod bow uncertainty ( ) (( }}2(a),(c) CHF correlation P/M (( }}2(a),(c) F E H1 F E H2 FE Q F RB H

NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties TR-169856-NP Revision 0 © Copyright 2024 by NuScale Power, LLC 14 4.0 Conclusion Section 3.0 of this report provides the information necessary to satisfy condition and limitation #2 of Reference 5.1 by defining the probabilistic uncertainties used in determining the SCHFAL for the NuScale US460 design. 5.0 References 5.1 NuScale Power, LLC, Statistical Subchannel Analysis Methodology: Supplement 1 to TR-0915-17564-P-A, Revision 2, Subchannel Analysis Methodology, TR-108601-P-A, Revision 4. 5.2 NuScale Power, LLC, NuScale Power Critical Heat Flux Correlations, TR-0116-21012-P-A, Revision 1. 5.3 U.S. Nuclear Regulatory Commission, Applying Statistics, NUREG-1475, Revision 1, March 2011. 5.4 U.S. Code of Federal Regulations, General Design Criteria for Nuclear Power Plants, Appendix A, Part 50, Chapter 1, Title 10, Energy, (10 CFR 50, Appendix A).

LO-172648 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Affidavit of Carrie Fosaaen, AF-172649

AF-172649 Page 1 of 2 NuScale Power, LLC AFFIDAVIT of Carrie Fosaaen I, Carrie Fosaaen, state as follows: (1) I am the Vice President 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 other trade secret by which NuScale develops its US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties. NuScale has performed significant research and evaluation to develop a basis for this other trade secret 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, NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties. 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.

AF-172649 Page 2 of 2 (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 § 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 July 31, 2024. Carrie Fosaaen

LO-172648 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Affidavit of Morris Byram, Framatome

A F F I D A V I T

1.

My name is Morris Byram. I am Product Manager, Licensing & Regulatory Affairs for Framatome Inc. (Framatome) and as such I am authorized to execute this Affidavit.

2.

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

3.

I am familiar with the Framatome information contained in Enclosure 1 entitled NuScale US460 Statistical Subchannel Critical Heat Flux Analysis Probabilistic Uncertainties, (TR-169856, Revision 0) to the NuScale Power, LLC letter Number LO-172648, and referred to herein as Document. Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.

4.

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

5.

This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.

6.

The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary: (a) The information reveals details of Framatomes research and development plans and programs or their results. (b) Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service. (c) The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome. (d) The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability. (e) The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome. The information in this Document is considered proprietary for the reasons set forth in paragraph 6(d) and 6(e) above.

7.

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

8.

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

9.

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

I declare under penalty of perjury that the foregoing is true and correct. Executed on: (7/16/2024) (NAME) Email: morris.byram@framatome.com Phone: 434-221-1082 BYRAM Morris Digitally signed by BYRAM Morris Date: 2024.07.16 15:35:18 -07'00'}}