ML25021A153

LLC, Response to NRC Request for Additional Information No. 031 (RAI-10296 R1) on the NuScale Standard Design Approval Application

ML25021A153
Person / Time
Site:	05200050
Issue date:	01/21/2025
From:	Shaver M NuScale
To:	Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML25021A152	List: ML25021A153
References
RAIO-178265
Download: ML25021A153 (1)

Text

RAIO-178265 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com January 21, 2025 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 Response to NRC Request for Additional Information No. 031 (RAI-10296 R1) on the NuScale Standard Design Approval Application

REFERENCE:

NRC Letter to NuScale, Request for Additional Information No. 031 (RAI-10296 R1), dated October 30, 2024 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).

The enclosure to this letter contains the NuScale response to the following RAI question from NRC RAI-10296 R1:

LOCA.LTR-51, 52, 54 is the proprietary version of the NuScale Response to NRC RAI No. 031 (RAI-10296 R1, Question LOCA.LTR-51, 52, 54). NuScale requests that the proprietary version be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390. The enclosed affidavit (Enclosure 3) supports this request. The enclosed affidavit (Enclosure 3) supports this request. Enclosure 1 has also been determined to contain Export Controlled Information. This information must be protected from disclosure per the requirement of 10 CFR § 810. Enclosure 2 is the nonproprietary version of the NuScale response.

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 January 21, 2025.

Sincerely, Mark W. Shaver Director, Regulatory Affairs NuScale Power, LLC

RAIO-178265 Page 2 of 2 01/21/2025 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 Ricky Vivanco, Project Manager, NRC

NuScale Response to NRC Request for Additional Information RAI-10296 R1, Question LOCA.LTR-51, 52, 54, Proprietary Version : NuScale Response to NRC Request for Additional Information RAI-10296 R1, Question LOCA.LTR-51, 52, 54, Nonproprietary Version : Affidavit of Mark W. Shaver, AF-178266

RAIO-178265 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com NuScale Response to NRC Request for Additional Information RAI-10296 R1, Question LOCA.LTR-51, 52, 54, Proprietary Version

RAIO-178265 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com NuScale Response to NRC Request for Additional Information RAI-10296 R1, Question LOCA.LTR-51, 52, 54, Nonproprietary Version

Response to Request for Additional Information Docket: 052000050 RAI No.: 10296 Date of RAI Issue: 10/30/2024 NRC Question No.: LOCA.LTR-51, 52, 54 Issue By letter dated January 6, 2023 (ML23011A012), NuScale submitted NRELAP5 files via DVD to support review of the loss-of-coolant accident (LOCA) licensing topical report (LTR), and other LTRs that support the SDAA. NuScale informed NRC in February 2024, that a code error was found. Subsequently, NuScale informed NRC that a new code version, NRELAP5 v1.7, was being released and would be used for the SDAA and supporting topical reports. (( 2(a),(c) Further, staff understands some design changes may have also impacted the base model. In addition, the staff notes that part of the code upgrade altered the critical flow model. Information Requested In order for the staff to complete its technical review of the analytical approach and base its findings on submitted information relevant to the version of the code utilized in developing the EM, NuScale is requested to: NuScale Nonproprietary NuScale Nonproprietary

a) Re-submit any of the remaining files impacted by this code version change. (( }} 2(a),(c) b) Provide a compiled listing of all changes to the base model, as well as a listing of, and a disposition for, changes to the design that may impact the base model but were determined to be insignificant and therefore did not require a change to the base model. c) Provide justification that the introduced code changes are either in conformance with the 10 CFR Part 50 Appendix K critical flow model requirement or that the changes to the critical flow modeling are more conservative. (( }} 2(a),(c) NuScale Response: Part a NuScale previously submitted (( }}2(a),(c) NRELAP5 version 1.7 (v1.7) in the following letter: NuScale letter to NRC, LO-172700, NuScale Power, LLC Submittal of Supplemental Information in Support of Review of TR-131981-P, Methodology for the Determination of the Onset of Density Wave Oscillations (DWO), Revision 1 Audit Question A-DWO.LTR-127, dated August 6, 2024. NuScale Nonproprietary NuScale Nonproprietary

In addition, NuScale previously submitted supporting information for NRELAP5 version 1.7 (v1.7) (( }}2(a),(c) in the following letter: NuScale letter to NRC, LO-175108, NuScale Power, LLC Submittal of Supplemental Information in Support of NRC Review of NuScale Topical Reports Associated with the Standard Design Approval Application, dated October 17, 2024. The October 17, 2024 letter contained the files shown in Table 1 below. NuScale is transmitting with this response LO-176112 to provide the files listed in Table 2. Together, the three submittals provide the information requested. NuScale Nonproprietary NuScale Nonproprietary

Table 1: Files Contained in LO-175108 NuScale Letter to the Nuclear Regulatory Commission (( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

Table 2: Files Contained in LO-176112 NuScale Letter to the Nuclear Regulatory Commission (( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

Part b As described in previous audit responses to A-LOCA.LTR-52, ((

}}2(a),(c) Table 3 below reorganizes the information presented in (( 
}}2(a),(c)

NuScale Nonproprietary NuScale Nonproprietary

(( }}2(a),(c) In this RAI, the NRC staff requests a list of design changes that may impact the NRELAP5 basemodel, but were not incorporated into the basemodel. (( }}2(a),(c) If the basemodel deviates from its design input documentation, justification is provided as part of the assumptions section of the basemodel document EC-0000-7782. NuScale Nonproprietary NuScale Nonproprietary

(( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

(( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

(( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

(( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

Part c (( }}2(a),(c) Results show that there are no significant changes between NRELAP5 v1.6 and v1.7. The results for the comparison between v1.6 and v1.7 are included in the LOCA LTR markup attached. NuScale performed comparisons of NRELAP5 v1.6 to v1.7 in EE-175345, Revision 0, Comparison Study of NRELAP5 version 1.6 and 1.7. The document EE-175345 is provided for NRC audit with this response. The relevant sections of EE-175345 for the LOCA topical report are indicated in the list below. (( }}2(a),(c) NuScale Nonproprietary NuScale Nonproprietary

(( }}2(a),(c) Impact on Topical Report: Topical Report TR-0516-49422, Loss-of-Coolant Accident Evaluation Model, has been revised as described in the response above and as shown in the markup provided in this response. NuScale Nonproprietary NuScale Nonproprietary

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 241 RAI LOCA.LTR-51, 52, 54 Figure 7-52a Measured Versus Calculated Mass Flow Rate for Marviken Critical Flow Test 22 - NRELAP5 Version 1.6 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 242 RAI LOCA.LTR-51, 52, 54 Figure 7-52b Measured Versus Calculated Mass Flow Rate for Marviken Critical Flow Test 22 - NRELAP5 Version 1.7 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 243 RAI LOCA.LTR-51, 52, 54 Figure 7-53a Marviken Critical Flow Test 22 Comparison to Calculated Mixture Density - NRELAP5 Version 1.6 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 244 RAI LOCA.LTR-51, 52, 54 7.2.11.5.2 Comparison to Marviken Critical Flow Test-24 (( }}2(a),(b),(c) Figure 7-53b Marviken Critical Flow Test 22 Comparison to Calculated Mixture Density - NRELAP5 Version 1.7 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 245

3. ((

}}2(a),(b),(c) RAI LOCA.LTR-51, 52, 54 Figure 7-54a Measured Versus Calculated Mass Flow Rate for Marviken Critical Flow Test 24 - NRELAP5 Version 1.6 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 246 RAI LOCA.LTR-51, 52, 54 Figure 7-54b Measured Versus Calculated Mass Flow Rate for Marviken Critical Flow Test 24 - NRELAP5 Version 1.7 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 247 RAI LOCA.LTR-51, 52, 54 Figure 7-55a Marviken Critical Flow Test 24 Mixture Density and Calculated Mixture Density - NRELAP5 Version 1.6 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 248 RAI LOCA.LTR-51, 52, 54 Analysis shows that NRELAP5 has the capability to perform critical flow calculations with reasonable-to-excellent agreement to test data. 7.3 NuScale Stern Critical Heat Flux Tests The CHF correlations described in Section 6.11 are assessed against steady state CHF experiments performed by NuScale in the Stern facility. This assessment is presented here. The Stern tests were performed on a preliminary prototypical bundle geometrically comparable to the NuFuel HTP2' design, but with ((

}}2(a),(b),(c),ECI The Stern preliminary prototypical bundle tests provide data over wide parameter ranges, which encompass the NPM operating parameter values and can be used to assess the capability of NRELAP5 to predict the onset of the CHF. Key FOMs to assess agreement include the critical power and the critical power ratio as a function of mass flux, pressure, and inlet sub-cooling.

Figure 7-55b Marviken Critical Flow Test 24 Mixture Density and Calculated Mixture Density - NRELAP5 Version 1.7 (( }}2(a),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 350 RAI LOCA.LTR-51, 52, 54 Figure 7-131a NIST-1 HP-49 Spurious Orifice Differential Pressure - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 351 RAI LOCA.LTR-51, 52, 54 Figure 7-131b NIST-1 HP-49 Spurious Orifice Differential Pressure - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 352 RAI LOCA.LTR-51, 52, 54 Figure 7-132a NIST-1 HP-49 Primary Mass Flow Rate - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 353 RAI LOCA.LTR-51, 52, 54 Figure 7-132b NIST-1 HP-49 Primary Mass Flow Rate - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 354 RAI LOCA.LTR-51, 52, 54 Figure 7-133a NIST-1 HP-49 Pressurizer Level Comparison - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 355 RAI LOCA.LTR-51, 52, 54 Figure 7-133b NIST-1 HP-49 Pressurizer Level Comparison - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 356 RAI LOCA.LTR-51, 52, 54 Figure 7-134a NIST-1 HP-49 Reactor Pressure Vessel Level Comparison - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 357 RAI LOCA.LTR-51, 52, 54 Figure 7-134b NIST-1 HP-49 Reactor Pressure Vessel Level Comparison - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 358 RAI LOCA.LTR-51, 52, 54 Figure 7-135a NIST-1 HP-49 Containment Vessel Level Comparison - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 359 RAI LOCA.LTR-51, 52, 54 Figure 7-135b NIST-1 HP-49 Containment Vessel Level Comparison - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 360 RAI LOCA.LTR-51, 52, 54 Figure 7-136a NIST-1 HP-49 Containment Vessel Peak Pressure Comparison - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 361 RAI LOCA.LTR-51, 52, 54 Figure 7-136b NIST-1 HP-49 Containment Vessel Peak Pressure Comparison - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 362 RAI LOCA.LTR-51, 52, 54 Figure 7-137a NIST-1 HP-49 Containment Vessel Pressure Comparison - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 363 RAI LOCA.LTR-51, 52, 54 Figure 7-137b NIST-1 HP-49 Containment Vessel Pressure Comparison - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 364 RAI LOCA.LTR-51, 52, 54 Figure 7-138a NIST-1 HP-49 Primary Pressure Comparison - NRELAP5 Version 1.6 (( }}2(a),(b),(c),ECI

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Revision 4 © Copyright 2024 by NuScale Power, LLC 365 RAI LOCA.LTR-51, 52, 54 7.5.10 NIST-2 LOCA Integral Effects Test Series This section documents the evaluation of the NIST-2 LOCA test data and the simulated NRELAP5 LOCA transient results. The LOCA test data are intended to provide a better understanding of phenomena related to Phase 1a and 1b for cases of CVCS, RVV, RRV, and high point vent line breaks scenarios. The NIST-2 LOCA test suite consists of the following characteristics:

The following transient scenarios (referred to herein as runs): Run 1 - 100% CVCS discharge line break (similar to NIST-1 HP-06). Run 2 - 100% high point vent line break (similar to NIST-1 HP-07). Run 3 - Inadvertent opening of a single RVV (similar to NIST-1 HP-09). Run 4 - Inadvertent opening of a single RRV (similar to NIST-1 HP-49). Figure 7-138b NIST-1 HP-49 Primary Pressure Comparison - NRELAP5 Version 1.7 (( }}2(a),(b),(c)

RAIO-178265 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 Mark W. Shaver, AF-178266

AF-178266 Page 1 of 2

NuScale Power, LLC AFFIDAVIT of Mark W. Shaver I, Mark W. Shaver, state as follows: (1) I am the 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 Request for Additional Information response reveals distinguishing aspects about the response by which NuScale develops its NuScale Power, LLC Response to NRC Request for Additional Information (RAI No. 10296 R1, Question LOCA.LTR-51, 52, 54) on the NuScale Standard Design Approval Application. NuScale has performed significant research and evaluation to develop a basis for this response 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, NuScales 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 NuScales 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 response to NRC Request for Additional Information RAI 10296 R1, Question LOCA.LTR-51, 52, 54. 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-178266 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 NuScales 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 January 21, 2025. Mark W. Shaver}}