ML24047A252

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LLC, Response to NRC Request for Additional Information No. 10115 (RAI No. 10115) on the NuScale Standard Design Approval Application
ML24047A252
Person / Time
Site: 05200050, 99902078
Issue date: 02/16/2024
From: Griffith T
NuScale
To:
Office of Nuclear Reactor Regulation, Document Control Desk
Shared Package
ML24047A251 List:
References
RAIO-157114
Download: ML24047A252 (1)


Text

RAIO-157114 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Docket No. 052-050 February 16, 2024 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. 10115 (RAI No. 10115) on the NuScale Standard Design Approval Application

REFERENCES:

1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 10115 (RAI No. 10115)," dated December 6, 2023 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).

The Enclosures to this letter contain NuScale's response to the following RAI Question from NRC RAI No. 10115:

19.1.5-1 is the proprietary version of the NuScale Response to NRC RAI No. 10115 (RAI No. 10115). 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. 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 Wren Fowler at 541-452-7183 or at sfowler@nuscalepower.com.

Sincerely, Thomas Griffith Manager, Licensing NuScale Power, LLC Distribution:

Mahmoud Jardaneh, NRC Getachew Tesfaye, NRC Alina Schiller, NRC

RAIO-157114 Page 2 of 2 02/16/2024 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 No. 10115, proprietary : NuScale Response to NRC Request for Additional Information RAI No. 10115, nonproprietary : Affidavit of Carrie Fosaaen, AF-157115

RAIO-157114 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 No. 10115, proprietary

RAIO-157114 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 No. 10115, nonproprietary

Response to Request for Additional Information Docket: 052000050 RAI No.: 10115 Date of RAI Issue:12/06/2023 NRC Question No.: 19.1.5-1 Regulatory Basis 10 CFR 52.137(a)(25) states that an SDAA must contain an FSAR that includes a description of the design-specific probabilistic risk assessment (PRA) and its results. The Statement of Considerations (SOC) for Part 52 (72FR49352) states, [t]he Commission has decided that the contents of applications for design approvals should contain essentially the same technical information that is required of design certification applications (e.g., demonstration of compliance with technically relevant Three Mile Island requirements, proposed technical resolutions of unresolved safety issues and medium and high-priority generic safety issues, and design-specific probabilistic risk assessment information) and many of the public comments on contents of applications for design certification apply to the requirements for design approvals.

Issue In SECY-93-087, the Commission approved the use of a PRA-based seismic margins analysis (SMA) for a design certification application (DCA) in lieu of a seismic PRA.

NUREG-0800, Standard Review Plan (SRP), Chapter 19.0, Revision 3, provides guidance on the methods acceptable to the staff to demonstrate low seismic risk, including the acceptance criteria for PRA-based SMA. The guidance includes the seismic fragility calculations based on design-specific information and the consideration of the accident sequences that require seismic fragility evaluation for determining sequence-level high confidence of low probability of failure (HCLPF) capacities.

Evaluating the seismic fragility is a key element of a PRA-based SMA and provides key insights to understand plant risk. A PRA-based SMA considers all sequences leading to core damage or containment failure. The results of the PRA-based SMA include characterization of the HCLPF capacities for select structures, systems, and components (SSCs) and sequence-level and NuScale Nonproprietary NuScale Nonproprietary

plant-level HCLPF capacities. Focusing on only those SSCs that contribute to the plant-level HCLPF capacity does not provide adequate information to support the staffs review of the development of and risk insights from the PRA-based SMA. Further, only providing HCLPF capacities does not provide adequate information for the staffs review of the fragility evaluation performed for the PRA-based SMA and the resulting uncertainties. Section 5.4, Position on Documentation of DC/COL-ISG-020 (ML100491233) specifies that fragilities for the SSCs in the seismic equipment list (SEL) as well as the sequence-level and plant-level HCLPF capacities, among others, be provided in Chapter 19 of the FSAR.

Due to the above reasons, NuScale SDAA FSAR Section 19.1.5.1, Seismic Risk Evaluation, does not provide sufficient information in Table 19.1-32 for the staff to effectively review the description and results of the PRA-based SMA, including the SSC fragility parameters and the corresponding uncertainty. The level of information necessary for the staff to make it finding on PRA-based SMA is consistent with that provided in the NuScale DCA FSAR Table 19.1-38.

Consequently, there is insufficient information in the SDAA FSAR to support the staffs finding on the PRA-based SMA per the regulatory basis identified above and the guidance in SRP Section 19.0, specifically under Design-Specific PRA (PRA-Based SMA) and the acceptance criteria in Section II of that guidance. The information requested hereunder is necessary for the staff to evaluate the PRA-based SMA, including its results, and make corresponding safety findings.

Information Requested To support the staffs finding on the PRA-based SMA against 10 CFR 52.137(a)(25), NuScale is requested to update the FSAR to include the following information in either an expanded Table 19.1-32 or in separate tables:

1. Key SSCs on the SEL that are considered important to understanding seismic risk insights, with their respective failure modes, fragility parameters (HCLPF, median capacity (Am)),

logarithmic standard deviation for randomness (beta_r), logarithmic standard deviation for uncertainty (beta_u), fragility evaluation method, and seismic correlation information.

2. Sequence-level HCLPF capacities for each seismically initiated accident sequence.

NuScale Nonproprietary NuScale Nonproprietary

NuScale Response:

1. NuScale proposes the following additional columns in FSAR Table 19.1-32, Seismic Margin Assessment Fragility: seismic correlation class, median seismic capacity (Am), randomness of the fragility evaluation (r), and uncertainty in the median seismic capacity (u). As described in FSAR Section 19.1.5.1.1.1, all structures, systems, and components (SSC) reported in Table 19.1-32 are design-specific and evaluated with the separation of variables fragility method. In addition to adding columns, NuScale has reorganized the controlling failure mode and assumed consequence information for valve fragilities included in the table and corrected errors in the HCLPF capacity values for the two bioshield entries and the controlling mode failure for the containment isolation valves. Lastly, NuScale has made several style and formatting improvements.
2. NuScale uses the MIN-MAX method to determine the plant-level HCLPF capacity for the US460 design. Per the MIN-MAX method, the plant-level HCLPF capacity is the minimum sequence-level HCLPF capacity. Each sequence-level HCLPF capacity is the minimum cutset HCLPF capacity. Each cutset HCLPF capacity is the maximum HCLPF capacity of the collection of SSC within the cutset (i.e., the controlling SSC). Table 1 below identifies the sequence-level HCLPF capacity for each seismically-induced sequence and the controlling SSC. Table 19.1-32 includes more information on the fragility analysis of these SSC. As described above, the plant-level HCLPF capacity is equal to the SSC associated with the minimum sequence-level HCLPF capacity. For the US460 design, the plant-level HCLPF capacity is 0.92g peak ground acceleration, which is associated with failure of the Reactor Building crane support.

Table 1: Sequence-Level High Confidence of Low Probability of Failure Capacities

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

Impact on US460 SDA: FSAR Section 19.1 FSAR Table 19.1-32 has been revised as described in the response above and as shown in the markup provided in this response. NuScale Nonproprietary NuScale Nonproprietary

NuScale Final Safety Analysis Report Probabilistic Risk Assessment NuScale US460 SDAA 19.1-147 Draft Revision 2 Audit Issue A-19.1-41 RAI 19.1.5-1 Table 19.1-32: Seismic Margin Assessment Fragility SSC HCLPF (g) Controlling Failure Mode Assumed Consequence Reactor Building Crane Supports 0.92g Weld failure Core damage/Large Release Bioshield - normal operation (single stack) 0.93g Bolt shear failure Core damage/Large Release Bioshield - refueling of adjacent NPM (double stack) 0.93g Bolt shear failure Core damage/Large Release when configuration present Reactor Building 0.97g Roof in-plane shear failure Core damage/Large Release Reactor Building Crane 1.11g Plate bending failure Core damage/Large Release NPM Supports 1.14g Weld failure Core damage/Large Release Reactor Recirculation Valves 1.38g Valve body deformation Valve failure to open Reactor Vent Valves 2.69g Valve body deformation Valve failure to open Containment Isolation Valves 3.92g Valve body deformation Valve failure to open Reactor Safety Valves 6.00g Valve body deformation Valve failure to open Trip Valves for Reactor Recirculation Valves 7.14g Valve body deformation Valve failure to open Trip Valves for Reactor Vent Valve 8.44g Valve body deformation Valve failure to open Note: - HCLPF = High-Confidence (95%) of a Low Probability (5%) of Failure (EPRI 103959)

NuScale Final Safety Analysis Report Probabilistic Risk Assessment NuScale US460 SDAA 19.1-148 Draft Revision 2 RAI 19.1.5-1 Table 19.1-33: Seismic Margin Assessment Fragility Seismic Correlation Class SSC Am (g) r u HCLPF (g) Controlling Failure Mode Assumed Consequence RBCS-145-RXB--WCL-SEIS Reactor Building Crane Supports 2.67 0.26 0.39 0.92 Weld failure Core damage/Large release BION-125-RXB--BSF-SEIS Bioshield - normal operation (single stack) 1.99 0.10 0.35 0.95 Bolt shear failure Core damage/Large release BIOR-125-RXB--BSF-SEIS Bioshield - refueling of adjacent NPM (double stack) 1.99 0.10 0.35 0.95 Bolt shear failure Core damage/Large release when configuration present RXB-----------IPS-SEIS Reactor Building 2.91 0.19 0.48 0.97 Roof in-plane shear failure Core damage/Large release RBC--145-RXB--PBL-SEIS Reactor Building Crane 3.45 0.24 0.45 1.11 Plate bending failure Core damage/Large release NPMS-80--RXB--WCF-SEIS NPM Supports 3.12 0.23 0.38 1.14 Weld failure Core damage/Large release POV--40--NPM--FTO-SEIS Reactor Recirculation Valves 3.83 0.26 0.36 1.38 Valve failure to open Note 1 POV--80--NPM--FTO-SEIS Reactor Vent Valves 7.09 0.25 0.34 2.69 Valve failure to open Note 1 HOV--100-NPM--FTC-SEIS Containment Isolation Valves 10.53 0.24 0.36 3.92 Valve failure to close Note 1 RSV--80--NPM--FTO-SEIS Reactor Safety Valves 15.58 0.26 0.32 6.00 Valve failure to open Note 1 SOV--60--NPM--FTO-SEIS Trip Valves for Reactor Recirculation Valves 20.85 0.24 0.31 8.44 Valve failure to open Note 1 SOV--70--NPM--FTO-SEIS Trip Valves for Reactor Vent Valves 18.84 0.25 0.34 7.14 Valve failure to open Note 1 Notes: - Am = median seismic capacity - r = randomness of the fragility evaluation - u = uncertainty in the median seismic capacity - HCLPF = high confidence (95%) of low probability (5%) of failure (EPRI 103959)

1. Component failures are contributors to plant response (e.g., failure of the RRVs to open results in ECCS failure)

RAIO-157114 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-157115

AF-157115 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 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. 10115) 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 10115 Chapter 19.1.5-1. 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-157115 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 February 16, 2024. Carrie Fosaaen}}