ML18268A365

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LLC Response to NRC Request for Additional Information No. 487 (Erai No. 9549) on the NuScale Design Certification Application
ML18268A365
Person / Time
Site: NuScale
Issue date: 09/25/2018
From: Rad Z
NuScale
To:
Document Control Desk, Office of New Reactors
Shared Package
ML18268A364 List:
References
AF-0918-61935, RAIO-0918-61934
Download: ML18268A365 (18)
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Text

RAIO-0918-61934 September 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.

487 (eRAI No. 9549) on the NuScale Design Certification Application

REFERENCE:

U.S. Nuclear Regulatory Commission, "Request for Additional Information No.

487 (eRAI No. 9549)," dated June 11, 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. 9549:

  • 06.02.01 .01 .A-21 Enclosure 1 is the proprietary version of the NuScale Response to NRC RAI No. 487 (eRAI No.

9549). 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 non proprietary version of the NuScale response.

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

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

Sincerely,

~~

..,-/Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A NuScale Power, LLC 1100 NE Circle Blvd. , Suite 200 Corvalis, Oregon 97330 , Office: 541.360.0500 , Fax: 541.207.3928 www.nuscalepower.com

RAIO-0918-61934 : NuScale Response to NRC Request for Additional Information eRAI No. 9549, proprietary : NuScale Response to NRC Request for Additional Information eRAI No. 9549, nonproprietary : Affidavit of Zackary W. Rad, AF-0918-61935 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-0918-61934 :

NuScale Response to NRC Request for Additional Information eRAI No. 9549, 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-0918-61934 :

NuScale Response to NRC Request for Additional Information eRAI No. 9549, 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: PROJ0769 eRAI No.: 9549 Date of RAI Issue: 06/11/2018 NRC Question No.: 06.02.01.01.A-21 NIST-1 RRV Opening Test and Validation for the Containment Response Analysis Methodology 10 CFR 50, Appendix A, Criterion 16, Containment design, states, "Reactor containment and associated systems shall be provided to establish an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment and to assure that the containment design conditions important to safety are not exceeded for as long as postulated accident conditions require."

10 CFR 50, Appendix A, Criterion 50, Containment design basis, states, "The reactor containment structure, including access openings, penetrations, and the containment heat removal system shall be designed so that the containment structure and its internal compartments can accommodate, without exceeding the design leakage rate and with sufficient margin, the calculated pressure and temperature conditions resulting from any loss-of-coolant accident. This margin shall reflect consideration of (1) the effects of potential energy sources which have not been included in the determination of the peak conditions, such as energy in steam generators and as required by § 50.44 energy from metal-water and other chemical reactions that may result from degradation but not total failure of emergency core cooling functioning, (2) the limited experience and experimental data available for defining accident phenomena and containment responses, and (3) the conservatism of the calculational model and input parameters."

10 CFR 50.43(e) states, in part, the use of simplified, inherent, passive, other innovative means to accomplish their safety functions will be approved only if:

NuScale Nonproprietary

(1)(i) The performance of each safety feature of the design has been demonstrated through either analysis, appropriate test programs, experience, or a combination thereof; and (1)(iii) Sufficient data exist on the safety features of the design to assess the analytical tools used for safety analyses over a sufficient range of normal operating conditions, transient conditions, and specified accident sequences, including equilibrium core conditions.

The design evaluation for the containment system provided in FSAR, Tier 2, Section 6.2.1.1.3 references the Containment Response Analysis Methodology (CRAM) technical report, TR-0516-49084. NuScale used the CRAM to determine the peak containment pressure as the key figure of merit for containment integrity, for all design basis events (DBEs) analyzed for the NuScale power module (NPM). The NPM containment response analysis results presented in FSAR, Tier 2, Table 6.2-2 show that (1) the limiting peak containment pressure DBE is an inadvertent opening of a reactor recirculation valve (RRV), which is the largest liquid space discharge, and (2) this event results in a peak calculated containment pressure within 5 percent of the containment design pressure. The CRAM technical report also references the NRELAP5 code assessment described in the Loss-of-Coolant Accident (LOCA) evaluation model (EM) topical report, TR-0516-49422. The NRELAP5 code assessment includes a single NIST-1 test to characterize the liquid-space discharge from a smaller chemical and volume control system (CVCS) line than the RRV opening. The assessment results for this event, presented in Sections 7.5.6.5 and 7.5.6.6 of TR-0516-49422, show that NRELAP5 ((2(a),(b),(c). Even though an inadvertent RRV actuation as the initiating event could lead to the most severe containment pressurization, no integral test was conducted to demonstrate that the NRELAP5 code can conservatively model the largest liquid space discharge from the RRV at the lowest discharge point in the NIST-1 containment, with bounding uncertainties. As the NRELAP5 code assessment does not include the limiting peak containment pressure event, and the non- limiting liquid space discharge included in the NRELAP5 code assessment appears to show that NRELAP5 (( }}2(a),(b),(c), the NRC staff is unable to reach a reasonable assurance finding that sufficient test data exist to assess NREALP5 over a sufficient range of transient and accident conditions. Therefore, the NRC staff requests that NuScale perform an assessment of the NRELAP5 code using an integral effects test where the initiating event is a discharge from an RRV at a representative altitude. The applicant is also requested to provide or make available for audit the additional test data and code assessment results for the limiting peak containment pressure event, and update the licensing documentation (e.g., CRAM technical report, LOCA EM topical report), accordingly. NuScale Nonproprietary

NuScale Response: The HP-49 test was performed at the NIST-1 facility and the test data was used to assess the capability of the NRELAP5 code to predict the integral response of the NIST-1 facility for a inadvertent reactor recirculation valve (RRV) opening event, inside containment. The HP-49 test data was made available for audit in the NuScale Rockville offices and NRC staff audited the test data on August 7-8, 2018. The NRELAP5 assessment calculation results for the HP-49 test were made available for audit in the electronic reading room on September 6, 2018. A summary of the HP-49 test and NRELAP5 assessment calculation results was added to the LOCA EM topical report TR-0516-49422, with results of assessments of key figures of merit, as shown in the attached change package. The HP-49 test is an integral effects test modeling a spurious RRV opening into containment. The test consists of: 

    *  ((
                                                              }}2(a),(b),(c)

During the test, recirculation through the RRVs is established and the long term cooling flow path through the ECCS valves is established. NuScale Nonproprietary

For the HP-49 test, (( 

                         }}2(a),(b),(c),ECI NRELAP5 v1.4 was used to simulate the NIST-1 HP-49 test. For the key figures of merit, RPV pressure, RPV level, CNV pressure, and CNV level, NRELAP5 predicted the data with overall reasonable to excellent agreement. NRELAP5 predicted the peak CNV pressure and the timing of ECCS actuation with reasonable agreement ((                                 }}2(a),(b),(c).

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

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 Appendix C. Spurious Reactor Recirculation Valve Opening Integral Effects Test C.1 Purpose The HP-49 test was performed at the NIST-1 facility and was used to assess the capability of NRELAP5 to predict the integral response of the NIST-1 facility for a spurious reactor recirculation valve (RRV) opening inside containment. The reactor recirculation line (RRL) and RRV connect the downcomer side of the RPV to the CNV. C.2 Facility Description The NIST-1 facility is described in Section 7.5.1. The entire NIST-1 facility except for the CVCS, PZR Spray, and DHRS was used for this IET, including:

  • the SG was active to remove heat from the primary side and drive natural circulation in conjunction with the electrically heated core during the steady state period
             *    ((
                                         }}2(a),(b),(c)
             *    ((
                                                        }}2(a),(b),(c)
  • the CPV was filled to accept rejected heat from the HTP C.3 Phenomenon Addressed The HP-49 test is an IET modeling a spurious RRV opening into containment. The pertinent phenomena addressed by this test are:
             *    ((
                          }}2(a),(b),(c),ECI

© Copyright 2016 2018 by NuScale Power, LLC 502

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 C.4 Experimental Procedure The experiment test procedure is consistent with the LOCA test procedure described in Section 7.5.1.6. When the CNV pressure reached the specified CNV transient initiation pressure, the spurious RRV was opened, initiating the transient. Within the NIST-1 facility, the ECCS actuation occurs when the compensated level in the RPV downcomer reads lower than a specified value. Once this occurs, open signals are sent to the remaining RRV and the RVVs. The opening of the ECCS valves causes a large amount of mass and energy transfer to occur between the RPV and the CNV over a short period of time. The CNV pressurization and heat-up occurs rapidly, followed by a long depressurization and cooldown profile. Test data was recorded for an extended period of time, into the long-term cooling phase. C.5 Special Analysis Techniques The RRV discharge line orifice has a length of approximately (( 

                        }}2(a),(b),(c),ECI and an ID of approximately ((                                           }}2(a),(b),(c),ECI Thus, the orifice has an L/D ratio roughly equal to ((                      }}2(a),(b),(c),ECI Analysis indicates that an NRELAP5 discharge coefficient near ((                                             }}2(a),(b),(c),ECI produces reasonable agreement with the spurious RRV flow rate inferred from test data, however, the literature determined value of ((                      }}2(a),(b),(c),ECI is used for the base case assessment.

The (( 

                                                                                                                          }}2(a),(c)

C.6 Assessment Results (HP-49) The NRELAP5 transient model is designed to simulate initial test conditions and includes logic that follows facility controls and test procedures. For this experiment, the spurious mass flow rate was not measured. The calculated spurious flow rate is reasonable because the differential pressure across the spurious RRV line orifice (Figure C-1), the RPV level response (Figure C-4), the CNV level response (Figure C-5), the RPV pressure response (Figure C-8), and the CNV pressure response (Figure C-6) are all in reasonable agreement for the pre-ECCS opening period of the transient. The NIST-1 v-cone flowmeter (measuring primary loop flowrate) is designed for positive single-phase liquid conditions. During the HP-49 test, two-phase conditions occur at the location of the v-cone meter. As shown in Figure C-2 NRLEAP5 captures the RPV primary-flow coast-down period after transient initiation with reasonable accuracy. Note that after (( 

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

© Copyright 2016 2018 by NuScale Power, LLC 503

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 The pressurizer level is compared in Figure C-3. The comparisons show reasonable agreement. NRELAP5 predicts complete draining of the pressurizer at about (( 

                        }}2(a),(b),(c),ECI NRELAP5 provides reasonable agreement for level response in the RPV and CNV as shown in Figure C-4 and Figure C-5. The CNV peak pressure and pressure response are also predicted with reasonable agreement to data as shown in Figure C-6 and Figure C-7. The timing of ECCS actuation is predicted with reasonable agreement to the test data. Primary pressure response is predicted with reasonable agreement (Figure C-8).

(( 

                                                                                                       }}2(a),(b),(c),ECI Figure C-1.        NIST-1 HP-49 spurious orifice differential pressure
  © Copyright 2016 2018 by NuScale Power, LLC 504

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 (( 

                                                                                                    }}2(a),(b),(c),ECI Figure C-2.        NIST-1 HP-49 primary mass flow rate

(( 

                                                                                                }}2(a),(b),(c),ECI Figure C-3.        NIST-1 HP-49 pressurizer level comparison
     © Copyright 2016 2018 by NuScale Power, LLC 505

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 (( 

                                                                                                 }}2(a),(b),(c),ECI Figure C-4.        NIST-1 HP-49 reactor pressure vessel level comparison

(( 

                                                                                                 }}2(a),(b),(c),ECI Figure C-5.        NIST-1 HP-49 containment vessel level comparison
  © Copyright 2016 2018 by NuScale Power, LLC 506

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 (( 

                                                                                               }}2(a),(b),(c),ECI Figure C-6.        NIST-1 HP-49 containment vessel peak pressure comparison

(( 

                                                                                               }}2(a),(b),(c),ECI Figure C-7.        NIST-1 HP-49 containment vessel pressure comparison
  © Copyright 2016 2018 by NuScale Power, LLC 507

Loss-of-Coolant Accident Evaluation Model TR-0516-49422-NP Draft Rev. 01 (( 

                                                                                                 }}2(a),(b),(c),ECI Figure C-8.        NIST-1 HP-49 primary pressure comparison
© Copyright 2016 2018 by NuScale Power, LLC 508

RAIO-0918-61934 : Affidavit of Zackary W. Rad, AF-0918-61935 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 Zackary W. Rad I, Zackary W. Rad, state as follows:

1. I am the Director, 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 process by which NuScale performs its integrated effects testing.

NuScale has performed significant research and evaluation to develop a basis for this process and has invested significant resources, including the expenditure of a considerable sum of money. The precise financial value of the information is difficult to quantify, but it is a key element of the design basis for a NuScale plant and, therefore, has substantial value to NuScale. If the information were disclosed to the public, NuScale's competitors would have access to the information without purchasing the right to use it or having been required to undertake a similar expenditure of resources. Such disclosure would constitute a misappropriation of NuScale's intellectual property, and would deprive NuScale of the opportunity to exercise its competitive advantage to seek an adequate return on its investment. AF-0918-61935

4. The information sought to be withheld is in the enclosed response to NRC Request for Additional Information No. 487, eRAI No. 9549. 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 September 25, 2018. 7 Zackary W. Rad AF-0918-61935}}

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