ML18298A360

LLC - Response to NRC Request for Additional Information No. 377 (Erai No. 9380) on the NuScale Design Certification Application

ML18298A360
Person / Time
Site:	NuScale
Issue date:	10/25/2018
From:	Wike J NuScale
To:	Document Control Desk, Office of New Reactors
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ML18298A359	List: ML18298A360
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RAIO-1018-62295
Download: ML18298A360 (17)

Text

RAIO-1018-62295 October 25, 2018 Docket No.52-048 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.

377 (eRAI No. 9380) on the NuScale Design Certification Application

REFERENCES:

1. U.S. Nuclear Regulatory Commission, "Request for Additional Information No. 377 (eRAI No. 9380)," dated March 02, 2018

2. NuScale Power, LLC Response to NRC "Request for Additional Information No. 377 (eRAI No.9380)," dated September 13, 2018

3. NuScale Power, LLC Response to NRC "Request for Additional Information No. 377 (eRAI No.9380)," dated October 1, 2018" 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 eRAI No. 9380:

06.02.01.01.A-5 The responses to RAI Questions 06.02.01.01.A-6 and 06.02.01.01.A-7 were previously provided in Reference 2 and Reference 3. This completes all responses to eRAI 9380. is the proprietary version of the NuScale Response to NRC RAI No. 377 (eRAI No.

9380). NuScale requests that the proprietary version be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390. The proprietary enclosures have been deemed to contain Export Controlled Information. This information must be protected from disclosure per the requirements of 10 CFR § 810. The enclosed affidavit (Enclosure 3) supports this request. Enclosure 2 is the nonproprietary version of the NuScale response.

This letter and the enclosed responses make no new regulatory commitments and no revisions to any existing regulatory commitments.

NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-1018-62295 If you have any questions on this response, please contact Paul lnfanger at 541-452-7351 or at pinfanger@nuscalepower.com.

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Sincerely, Manager, Licensing NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A : NuScale Response to NRC Request for Additional Information eRAI No. 9380, proprietary : NuScale Response to NRC Request for Additional Information eRAI No. 9380, nonproprietary : Affidavit of Thomas A. Bergman, AF-1018-62296 NuScale Power, LLC 1100 NE Circle Blvd. , Suite 200 Corvalis, Oregon 97330 , Office: 541.360.0500 , Fax: 541.207.3928 www.nuscalepower.com

RAIO-1018-62295 :

NuScale Response to NRC Request for Additional Information eRAI No. 9380, proprietary NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-1018-62295 :

NuScale Response to NRC Request for Additional Information eRAI No. 9380, nonproprietary NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

Response to Request for Additional Information Docket No.52-048 eRAI No.: 9380 Date of RAI Issue: 03/02/2018 NRC Question No.: 06.02.01.01.A-5 Liquid Water Temperature Stratification inside the Containment To meet the General Design Criteria (GDCs) 16, 38, and 50 relevant to the containment design basis and guided by the Standard Review Plan (SRP), the staff is reviewing the applicants analytical models and analysis results that are used for the licensing-basis safety analyses. Specifically, the staff needs to assess the licensing-basis models, constitutive/closure relations, and model input parameters used for the applicants NPM design basis event (DBE) containment response analyses, in order to conclude that the results are valid over the applicable range of DBE conditions. The regulatory bases identified above are applicable to all questions in this RAI.

As shown in the NuScale Final Safety Analysis Report Table 6.2-2, Containment Analysis Response Results, the limiting transient for containment peak pressure is an inadvertent opening of a reactor recirculation valve (RRV). The NRELAP5 analysis of this transient shows that the pressurized RCS liquid flowing into the CNV will start flashing into steam. As the CNV pressure increases from approximately 2 psia at the start of the transient up to the peak containment pressure, a smaller fraction of the liquid would flash to steam since the degree of superheat is reduced as the containment pressure increases. The liquid falls to the lower bottom of the containment where the condensate from the flashed steam condensing on the cold containment wall also gets accumulated. The condensate eventually becomes subcooled due to CNV pressurization and the heat transfer from the liquid to reactor pool through the CNV wall.

NRELAP5 is expected to calculate the flashing/separation of the steam and liquid entering the CNV and liquid water falling to the bottom of the CNV. As the liquid temperature of water entering the CNV increases with time, thermal stratification of this water accumulating in the CNV is expected.

NuScale Nonproprietary

NRELAP5 should be able to accurately calculate this potentially safety-significant, non-equilibrium thermodynamic process. This is important because overestimating the temperatures of the stratified subcooled water inventory in the lower CNV could lead to a lower calculated containment pressure - a non-conservative result. However, the NRELAP5 model of the NPM uses only a few large volume nodes to represent the portion of the CNV volume below the liquid steam interface, and it is not clear whether NRELAP5 accurately simulates the temperature stratification phenomenon in the liquid water accumulated in the CNV. The NRELAP5 peak CNV pressure will be under predicted if the NuScale NRELAP5 model overestimates the mixing and cooling of CNV steam by this relatively cool water in the lower CNV. Thus, a conservative NRELAP5 model for temperature stratification that minimizes the steam cooling by the water accumulating in the CNV, and thus leads to a conservative distribution of energy in the CNV liquid and vapor phases, would be required in a conservative CNV peak pressure analysis.

The staff needs a greater understanding to assess the safety significance of the thermally stratified water in the CNV of the NPM during blowdown out to the time of peak containment pressure. NuScale is requested to provide additional information to enable the staff to assess the impact of liquid thermal stratification and nodalization in the CNV liquid region. For example, NuScale could provide (or make available) a revised nuclear power module (NPM) analysis for the limiting peak CNV pressure design basis event of inadvertent opening of an RRV with sufficiently fine hydrodynamic noding in the CNV liquid region. If additional analysis is performed, please provide (or make available) overlay plots that compare the impact of the revised nodalization on the computed liquid temperature and enthalpy versus time for the nodes up to the node where the liquid/steam interface occurs at the time of peak pressure. This will allow the staff to assess how NRELAP5 evaluates/treats the impact of subcooled water temperature stratification on the calculated CNV peak pressure.

NuScale Response:

The updated containment vessel (CNV) response analysis evaluated effects of using a set of coarser and finer axial nodalizations for the CNV volume, a finer reactor pool nodalization, and a finer CNV heat structure radial nodalization to determine the most limiting nodal representation with respect to CNV peak pressure and temperature. The CNV pressure and temperature response results for primary and secondary side events were compared to determine the limiting nodal representations of the axial CNV volume, radial CNV heat structure and axial reactor pool volume. ((2(a),(c) NuScale Nonproprietary

((

                                                           }}2(a),(c)

The following figures depict the base model nodalization, the coarser and finer CNV volume nodalization, the finer reactor pool volume nodalization, and the finer CNV heat structure radial nodalization schemes evaluated by this analysis. NuScale Nonproprietary

((

                                                }}2(a),(c),ECI Figure 1 - Base CNV/Reactor Pool Nodalization NuScale Nonproprietary

((

                                             }}2(a),(c),ECI Figure 2 - Coarser CNV Volume Nodalization NuScale Nonproprietary

((

                                           }}2(a),(c),ECI Figure 3 - Finer CNV Volume Nodalization NuScale Nonproprietary

((

                                                    }}2(a),(c),ECI Figure 4 - Finer Reactor Pool Volume Nodalization NuScale Nonproprietary

((

                                                                                              }}2(a),(c)

((

                                                                                              }}2(a),(c)

The nodalization sensitivity study determined the following for primary side release events: CNV Axial Nodalization ((

                                                                                      }}2(a),(c)

NuScale Nonproprietary

((

                           }}2(a),(c)

CNV Heat Structure Radial Nodalization There is no consistent trend indicating which CNV heat structure radial nodalization (coarse or fine) is limiting with respect to peak CNV pressure and wall temperature for primary side events. For most events, the effect of a finer CNV heat structure radial nodalization on peak CNV pressure and temperature is not significant (i.e. <1 psi and <0.5 °F difference from the base cases). Therefore, the most limiting CNV heat structure radial nodalization specific to each event based on these sensitivity results were included in the response analysis for each event. Specifically, the fine heat structure nodalization model resulted in a slight increase in peak pressure and peak temperature, in comparison to the base axial model, and was included in the model for the limiting peak pressure inadvertent RRV opening event and peak wall temperature for the limiting CVCS injection line break event. Reactor Pool Volume Axial Nodalization There is no consistent trend indicating which reactor pool nodalization (coarse or fine) is limiting with respect to peak CNV pressure and wall temperature for primary side events. In general, the effect of a finer reactor pool nodalization on peak CNV pressure and temperature is not significant (i.e. ~0.5 psi and ~0.5°F difference from the base cases). Therefore, the most limiting pool nodalization specific to each event based on these sensitivity results were included in the response analysis for each event. The fine reactor pool nodalization was used for the limiting CNV peak pressure inadvertent RRV opening event analysis, since it resulted in a slight increase in peak pressure. The base reactor pool nodalization resulted in slightly more conservative peak CNV wall temperature results and was used in the limiting CVCS injection line break event analysis. The nodalization sensitivity study determined the following for secondary side events: CNV Axial Nodalization For the feedwater line break, the fine CNV axial nodalization is more limiting with respect to peak CNV pressure and temperature, for the reasons discussed above for the primary system event analyses. Because the steam line break does not result in a significant accumulation of NuScale Nonproprietary

liquid inventory in the CNV prior to break isolation, the CNV axial nodalization is not as significant to the peak CNV conditions for this event. CNV Heat Structure Radial Nodalization For both the feedwater and steamline break events, the fine CNV heat structure radial nodalization is limiting with respect to peak CNV pressure and wall temperature, although the effect is not significant (i.e. ~2 psi and ~3 °F difference or less from the base cases). Therefore, the most limiting CNV heat structure radial nodalization based on these sensitivity results was included in the combination cases for each event. Reactor Pool Volume Axial Nodalization For both the feedwater and steamline break events, variation of reactor pool axial nodalization does not significantly impact the base case peak CNV pressure or temperature, especially since the peak CNV conditions are reached so quickly after isolation of the secondary side break. ((

                                                                           }}2(a),(c)

Impact on DCA: There are no impacts to the DCA as a result of this response. NuScale Nonproprietary

RAIO-1018-62295 : Affidavit of Thomas A. Bergman, AF-1018-62296 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

NuScale Power, LLC AFFIDAVIT of Thomas A. Bergman I, Thomas A. Bergman, state as follows:

1. I am the Vice President, 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 competitor's 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 NuScale's competitive position and foreclose or reduce the availability of profit-making opportunities. The accompanying Request for Additional Information response reveals distinguishing aspects about the analyses by which NuScale develops its NIST-1 HP-02 testing.

NuScale has performed significant research and evaluation to develop a basis for this analyses 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. AF-1018-62296

4. The information sought to be withheld is in the enclosed response to NRC Request for Additional Information No. 377, eRAI 9380. 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§ 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 October 25, 2018. AF-1018-62296}}