ML18302A409

LLC - Submittal of Response to Request for Additional Information (Rals) on NuScale Closure Plan for Final Safety Analysis Report, Tier 2, Sections 3.7 and 3.8

ML18302A409
Person / Time
Site:	NuScale
Issue date:	10/29/2018
From:	Rad Z NuScale
To:	Document Control Desk, Office of New Reactors
Shared Package
ML18302A408	List: ML18302A409
References
LO-1018-62277
Download: ML18302A409 (17)

Text

LO-1018-62277 October 29, 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 Submittal of NuScale Closure Plan for Final Safety Analysis Report, Tier 2, Sections 3.7 and 3.8 Request for Additional Information (RAls)

REFERENCE:

Request for Seismic Design Issues Closure Plan for the Nu Scale Power, LLC, January 22, 2018, Gregory Cranston to Thomas Bergman (ML17348A916)

The purpose of this letter is to transmit the closure plan requested in Reference 1 for the Chapter 3 (Structural) RAI Responses. This closure plan includes the approach NuScale will take to respond to the RAI questions, the actions to be performed for closing and completing each response, and a schedule for submitting the final responses. This closure plan also includes updates from discussions held at the ongoing bi-weekly meetings between NRC and NuScale on this subject. is the proprietary version of the NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAls. 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 1) supports this request. is the nonproprietary version of the document entitled NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAls.

This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.

If you have any questions, please contact Marty Bryan at 541-452-7172 or at mbryan@nuscalepower.com.

Sin~ff~

Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A Mariela Vera, NRC, OWFN-8G9A : NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAls, proprietary version : NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAls, nonproprietary version : Affidavit of Zackary W. Rad, AF-1018-62347 NuScale Power, LLC 1100 NE Circle Blvd, Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 1

8971 03.08.04-13 10 CFR 50, Appendix A, GDC 1, 2, and 4, provide requirements to be met by SSC important to safety. In accordance with these requirements, DSRS Section 3.8.4 provides review guidance pertaining to the design of seismic Category I structures, other than the containment. Consistent with DSRS Section 3.8.4, the staff reviews loads and loading combinations.

FSAR Section 3.8.4.4.1 indicates that an ANSYS model was created to evaluate the effects of thermal loads on the structure. Further, FSAR Section 3.8.4.5 indicates that load combination 10 from Table 3.8.4-1 has been determined to be the controlling load combination. The staff request the applicant to provide the following information.

a) Magnitude of the bounding forces and moments profiles for walls and basemat resulting from thermal loads, To and Ta. Clarify whether such values were used in the load combinations 10 and 13 in Tables 3.8.4-1.

b) Describe how load combination 10 was determined to be the controlling load combination instead of load combination 13, and provide an example of how the loads were combined.

1) Provide the magnitude rebar strains for pilasters, walls and basemat resulting from thermal loads To, Ta and Pa.

2) Describe how load combination 10 was determined to be the controlling load comination instead of load combination 13 The following approach will be taken to address the above information:

- The rebar strains will be extracted from the finite element models for To, Ta and Pa.

- Clarify whether these extracted forces and moments are used in load combinations 10 and 13, if so how.

- The treatment of To and Ta induced rebar strains is to be substantiated with quantitative information justifying the treatment of such effects in the RXB design. (This comment is applicable to the entire RXB, including pilasters, walls, basemat, etc...)

- Review the determination of the controlling load combination, including an example of how the loads were combined in load combinations 10 and 13 including To and Ta and other non thermal loads.

- Revise FSAR Section 3.8.4 text and tables 3.8.4-1.

To clarify RAI 8967, Question 3.8.4-6, we will provide a description of how temperature induced loads were addressed in the design of the pilasters and provide a basis for the treatment of temperature induced loads. And the basis for the treatment of piping and equipment reactions (Ro).

12/11/2018 The design check for the reactor building (RXB) in FSAR was performed for the load combinations involving static loads, dynamic loads (Ess) and equivalent static loads from hydrodynamic pressure inside the pool (Referred to as SDH in the following load combinations).

These loads are parts of Load Combinations 9-6 and 9-9 as defined in Section 9.2.1 of ACI 349-

06. However, the design criteria for the RXB include load combinations that contain operating temperature (T0), accident temperature (Ta), and accidental pressure (Pa) effects. The third bullet in Section 1.3 of ACI 349.1R-07 (Reference 6) states the following:

"In nuclear power structures, the controlling load combinations are generally those that include Eo and Ess. These load cases provide sufficient reinforcement to control cracking. It would be counterproductive to add reinforcement to mitigate thermal effects because the additional reinforcement would stiffen the structure, thus increasing the stresses due to thermal effects.

This is unnecessary because thermal effects typically self-relieve without the need for additional reinforcement."

In order to provide response to to the RAI, the thermal loads T0 and Ta, and the pressure load Pa are now defined and hence the design check evaluation is enhanced for the load combinations of equations 9-6 and 9-9 of the ACI 349-06 code. The two load combinations that involve T0, Ta, and Pa are shown below:

• LC 9-6: COMB-Static (1GZ+H+F+0.8L) + Ess + 0.28GZ + T0 = SDH + T0

• LC 9-9: COMB-Static (1GZ+H+F+0.8L) + Ess + 0.28GZ + Ta + Pa = SDH + Ta + Pa For the design check with thermal and accidental pressure load, the total strain in the reinforcing steel calculated and determined to be less than 1.2y, the section is considered acceptable based on the 4th bullet in Section 1.3 of ACI 349.1R-07, which states the following about the reinforcing steel strain with thermal gradient, 1.2y: "Such an exceedance is inconsequential, and will not reduce the capacity of the concrete section for mechanical loads." Therefore, our effort has focused on using a detailed ANSYS 3D FEA model that explicitly include the section rebars (roof, walls, slabs, pilasters, buttresses, and foundation) to determine the new design demands that are additive the SDH loads.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 2

8911 03.09.02-18 10 CFR 52.47 requires the design certification applicant to include a description and analysis of the structures, systems, and components (SSCs) sufficient to permit understanding of the system designs. TR-0916-51502-P, Rev. 0, NuScale Power Module Seismic Analysis describes the methodologies and structural models that are used to analyze the dynamic structural response due to seismic loads acting on the NuScale Power Module (NPM). The description is insufficient for staff to reach a safety finding. Specifically, the report does not provide the seismic and LOCA stress results. Please provide the seismic analysis details and stress results under Service Level D condition for the following reactor internals components.

Include the requested information in the NPM Seismic Report or in separate reports.

- core support assembly (core barrel, lower core plate, reflector, upper core plate, - upper core support)

- lower riser assembly

- upper riser assembly (upper riser, upper riser hanger support)

- control rod assembly guide tube, control rod assembly guide tube support, control rod assembly card, control rod drive shaft, and control rod drive shaft support - steam generator tubes and tube supports

- control rod assembly guide tubes Service Level D Evaluation of Internals NuScale is currently working on the RVI and SG Level D stress analysis and expects to provide the RAI responses by the specified due date.

The responses will be based on two stress analysis documents:

(1) The SG stress analysis uses the latest SSE ISRS and all other applicable loadings for Level D, to qualify steam generator tubes and tube supports; (2) The RVI stress analysis uses the latest SSE ISRS and all other applicable loadings for Level D, to qualify all the internal components except for SG tubes and tube supports; The stress analysis results are not intended to be included as part of the seismic technical report.

10/25/2018 11/21/2018 The component analysis should include a brief description of the component structure modelling, input motion (time history or in-structure response spectrum), major assumptions, acceptance criteria under Service Level D condition including stress and deflection limits, fluid modelling, mass distribution, damping values, gap considerations, dominant modes and frequencies, and seismic and LOCA stress results and ASME B&PV Code Section III stress evaluation under Service Level D condition.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 3

8933 03.07.02-16 In FSAR Section 3.7.2.1.2.1, the staff noted that the dry dock is assumed to be full of water and part of the UHS in the seismic analysis. The nominal water level is at EL. 94 ft. In FSAR Section 9.1.3, the staff also noted that the dry dock can be drained partially or completely to support plant operations. In FSAR Section 9.1.3.3.5, the staff further noted that a failure of the dry dock gate while the dry dock is empty could result in a decrease in water level at the UHS pool by about 12 ft. Since the dry dock contains a large body of water, draining of a large mass of water could affect the dynamic characteristics of the SASSI and ANSYS models thereby potentially affecting the seismic demand based on full dry dock assumption. Provide a technical basis for not considering different water level conditions for the dry dock in the seismic analysis. In addition, the applicant should address the effect of potential variation in water level of the UHS on the seismic analysis of the RXB and NPM including the analyses conducted in FSAR 3.7.2.9.1 to address the effect of operation with less than the full complements of NPMs.

NuScale will provide, in a RAI response, further clarification of the operating band level for the RXB pool water. In addition, a description of the dry dock gate analysis and design criteria to ensure that no adverse seismic interaction occurs between the dry dock gate and adjacent SSCs. The maximum design loads for the dry dock gate occur when the pool is full. Technical justification will be provided through a parametric study comparing design forces with an empty dry dock for confirmation to show that the dry dock gate has been designed to the bounding load case and will not fail under a safe shutdown earthquake (SSE). With this, NuScale does not believe it is necessary to account for a 12 foot drop in the UHS pool water level in the dynamic analyses. To support the response:

1. A sensitivity study will be performed which assesses the global response of the structure when the dry dock is empty. The study will look at the empty dry dock effects within the structure at key locations to ensure that adequate margin is maintained in this scenario. This will be done by comparing ISRS and transfer functions at locations in the structure such as the module support, pool floor, and roof.

• Description of the SSI analysis with the empty dry dock including the parameters; e.g., cracked and/or uncracked model, structural damping values, and the soil properties, as well as the input spectra (CSDRS, CSDRS-HF) selected for the study and their basis.

• Markup of appropriate FSAR Sections (e.g., 3.7, 3.8, 9.1.3, etc.)

2. Clarify that we only have a 1 foot operating band of water level, and make revisions to FSAR Sections in chapter 9 as necessary, and thus there really is no effect of the variation of water level 10/31/2018 4

9309 03.08.04-37 In its response to RAI 8971, Question 03.08.04-12, the applicant indicated that the jet impingement, pipe break reaction, and missile impact loads are to be addressed by the COL applicant as per COL items 3.6-2 and COL item 3.6-3. Based on the applicants response, it is not clear to the staff what provisions have been incorporated in the current design to accommodate the aforementioned loads that will be established by the COL applicant and are to be combined with other loads as per Load Combinations 13 and 17 in FSAR Tables 3.8.4-1 and 3.8.4-2, respectively. Therefore, the staff request the applicant to provide the technical basis that demonstrate the adequacy of the RXB to withstand the demands from Load Combinations 13 and 17.

Additionally, the staff requests the applicant to clarify the locations in the RXB where these loads are expected to occur and address the comparison of the site-specific loadings (as per load combinations 13 and 17) with the standard design loadings in the existing COL item 3.8-2 or a new COL item.

Further, the staff request the applicant to update the FSAR markups proposed in its response to RAI 8971, Question 03.08.04-12, as applicable.

1) Provide the technical basis that demonstrates the adequacy of the RXB to withstand the demands from Load Combinations 13 and 17

2) Provide clarification regarding the locations in the RXB where respective loads are expected to occur and address the comparison of the site-specific loadings with the standard design loadings as in the existing COL item 3.8-2.

The following approach will be taken to address the above information:

- Describe preliminary locations of high energy pipe locations in the RXB.

- Provide the magnitude of the resulting or assumed loads for jet impingement, pipe break and missile impact with description of technical basis or assumption

- Evaluate pipe break and describe mass and energy ventilation strategy

- Show that for representative areas that the structural elements are adequate. If these locations are not previously addressed in FSAR, add new design details.

• D/C ratios for areas subject to jet impingement, pipe break reaction, and missile impact loads.

• Additional FSAR Sections to be updated including Section 3.6, 3.8.4.8 (and other 3.8.4 subsections as applicable), Appendix 3B, and other chapter 3 section as applicable.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 5

9447 03.11-19 This is a follow-up RAI to eRAI 9160.

NuScale's FSAR Chapter 3 describes that the environmental conditions of design basis accidents under the bioshield are established assuming a vented bioshield (Appendix 3C and Figure 3C-3). In a response to RAI 9160, the applicant describes that the bioshield relieves (i.e., vents) the high pressure and temperature environment under the bioshield by opening relief panels. The panels are required to change position from normally closed to open in order to vent the atmosphere under the bioshield into the reactor building. The panels are hinged and provide one-way relief (venting) in response to a HELB under the bioshield.

NuScale's response to RAI 9160 describes in part that all the bioshield functions, including the venting function, are nonsafety-related. If the function of a component or part is nonsafety-related, the staff expects that its failure to function could not prevent the satisfactory performance of a safety-related function. As discussed above, NuScale's FSAR Chapter 3 safety analysis, which establishes the environmental conditions under the bioshield for items related to safety, currently assumes a vented bioshield (e.g., opening nonsafety-related relief panels discussed in response to RAI 9160).

Therefore, the staff requests NuScale to assess the failure of the venting function (i.e., nonsafety-related bioshield relief panels do not open) and its impact on the performance of equipment important to safety (e.g., safety-related).

NRC concern: FSAR Chapter 3 safety analysis currently assumes a vented bioshield and the bioshield vents (relief panels) are nonsafety-related, FSAR Chapter 3 safety analysis (e.g., under the bioshield HELB environmental conditions for pressure and temperature) should be revised assuming bioshield venting is not achieved by the relief panels. Otherwise, NuScale will need to provide additional information to justify reliance on the bioshield relief panels (vents) in its safety analysis.

NuScale position:

NuScale is working to redesign the bioshield with the goal of eliminating the blow-out panels. This work is related to the HELB work and there are monthly meetings between NRC and NuScale to update the status of development. A meeting was held 8/16/2018.

11/20/2018 As part of the response, because the FSAR Chapter 3 safety analysis currently assumes a vented bioshield and the bioshield vents (relief panels) are nonsafety-related, FSAR Chapter 3 safety analysis (e.g., under the bioshield HELB environmental conditions for pressure and temperature) should be revised assuming bioshield venting is not achieved by the relief panels. Otherwise, NuScale will need to provide additional information to justify reliance on the bioshield relief panels (vents) in its safety analysis.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 6

8932 03.07.02-5 10 CFR 50 Appendix S requires that the safety functions of structures, systems, and components (SSCs) must be assured during and after the vibratory ground motion associated with the Safe Shutdown Earthquake (SSE) through design, testing, or qualification methods. On Page 3.7-22 of the FSAR, in the fourth paragraph, the applicant states, However due to the size and complexity of these models it is not practical to review transfer functions at all the nodes in the models. The staff views that the applicant may not need to review transfer functions (TFs) at all nodes; however, the staff views that TFs at key locations should be reviewed to ensure the adequacy of the SSI models and methodologies implemented in the seismic analyses. Therefore, the applicant is requested to provide information on TFs (in plots) at selected nodes of the critical sections and other important locations in the RXB and CRB. The plots should be inspected whether spurious spikes in the TFs are present within the frequency range of interest to the SSI analysis; and, if spikes are present, the applicant should discuss their potential effects on computed seismic demands.

NuScale will provide, through the RAI response, additional transfer function plots at key nodes in critical sections within the RXB and CRB. The plots will be supplemented with a discussion of potential effects of spurious spikes where applicable. The transfer functions will be extracted from a sampling of the SSI analyses that have been used for design of the plant:

1. Revise CRB and RXB SSI ISRS calculations to include additional transfer function data at critical node locations.

2. TFs at those key locations will be reviewed to ensure the adequacy of the SSI models and methodologies implemented in the seismic analyses.

3. The new plots will be inspected whether spurious spikes in the TFs are present within the frequency range of interest to the SSI analysis; and, if spikes are present, their potential effects on computed seismic demands will be investigated to assess whether further refinement or interpolation steps are necessary.

Tier 2 Section 3.7.2.1.1.3 of the FSAR will be updated to include additional descriptions of the transfer functions at critical locations and provide TF plots are critical locations. Any spikes observed in the frequency range of interest will be further explained.

11/29/2018 7

8935 03.07.02-26

a. In FSAR Subsection 3.7.2.5.2, the applicant indicates that the ISRS from the triple building model were considered for the design of SSCs in the RXB but not for the CRB. It is expected that the structure-soil-structure interaction (SSSI) effect would be more pronounced on a lighter building (CRB) than a neighboring heavier building (RXB). The applicant is requested to provide justification for not considering the ISRS from the triple building model for the design of SSCs in the CRB.

b. Figures 3.7.2-106 and 107 in the FSAR present the Reactor Building ISRS for floor at EL 24 and EL 25, respectively, which indicates noticeable difference in ISRS (both in shape and amplitude) for an elevation difference of only 1 foot. The applicant is requested to discuss the factors contributing to this observed difference.

1) The ISRS from the triple building model for the design of SSCs in the CRB will be provided.

ISRS will be developed in accordance with RG. 1.122 "Development of Floor Design Response Spectra for Seismic Design of Floor-Supported Equipment or Components" and the NuScale Seismic Design Criteria. FSAR Section 3.7.2 will be updated to include details on the ISRS.

2) The approach to be used is the same process used for the RXB.

3) A discussion of the factors contributing to the difference in the RXB ISRS will be provided.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 8

8933 03.07-02-17 10 CFR 50 Appendix S requires that the safety functions of structures, systems, and components (SSCs) must be assured during and after the vibratory ground motion associated with the Safe Shutdown Earthquake (SSE) through design, testing, or qualification methods.

a. Figure 3.7.2-13 in the FSAR indicates that the refueling area foundation is lower than the neighboring reactor pool and spent fuel pool area (which is also mentioned in the bottom paragraph on Page 3.7-24, indicating a six feet elevation difference). However, Figure 3.7.2-20 does not indicate these differences in foundation elevation. The applicant is requested to clarify whether these foundation elevation differences are taken into account in the RXB model; and, if not, please provide justification for not doing so.

b. On Page 3.7-25 of the FSAR, in the sixth paragraph, the applicant states, The rigid springs have a zero length and have a stiffness value large enough to simulate rigid connection. The large stiffness used is arbitrarily chosen to be ten billion lbs per inch, or 1010 lbs/inch, in the three global directions.

For the spring to be modeled as a rigid spring, the value of its spring constant should be sufficiently larger than the stiffness of the structural element (basemat) to which it is attached. The applicant is requested to confirm the adequacy of the number (1010 lbs/inch) chosen for the spring constant by comparing it to the stiffness of the adjacent basemat element or through an appropriate sensitivity run using a number at least an order of magnitude different.

a) Clarification will be provided regarding the foundation differences, and the implication of such on the analytical modeling. FSAR Section 3.7.2 will be updated to state the justification for the basemat modeling.

'b) NuScale will provide, through the RAI response, a sensitivity study with summarized results to support the selection of the large 10e10 lbs/inch stiffness value used for the rigid springs. An alternate sensitivity study will be presented to justify the use of the rigid springs in the analyses.

The goal of these rigid springs is to connect the soil nodes to the structural element nodes without compromising the soil-structure interaction and building response. Therefore, to demonstrate the validity of the element stiffness, a comparison of relative displacements will be provided between the two nodes of the spring element (I and J) to demonstrate the rigid behavior using the 10e10 lbs/inch stiffness:

1. Using a sampling of SSI analysis cases, extract the relative displacements between the I and J nodes of the rigid spring elements.

2. Clarify that the differential displacement at I and J nodes of rigid link is very small (10-5 in),

demonstrating rigid behavior.

3. Include results of relative displacements and justification of stiffness in the seismic SSI calculations.

Section 3.7.2.1.2.1 will be supplemented to summarize the conclusions of the study and provide technical justification confirming the 10e10 lbs/inch stiffness property simulates a rigid connection.

12/20/2018

c. In Table 3.7.2-1 in the FSAR, the maximum aspect ratio for RXB finite elements is indicated as 11.9. The applicant is requested to ensure that this value of aspect ratio is within the range of the parameters covered in the SASSI V&V; if not, provide justification for the adequacy of using the maximum aspect ratio of 11.9 for RXB finite elements.

c) All finite elements used were within the bounds of the V&V of the software. Some larger elements were used as a way to apply surface loads to the structure, and these elements tend to have larger aspect ratios. However, much smaller elements were used for the dynamic characteristics of the structure.

9 8935 03.07.02-25 10 CFR 50 Appendix S requires that the safety functions of structures, systems, and components (SSCs) must be assured during and after the vibratory ground motion associated with the Safe Shutdown Earthquake (SSE) through design, testing, or qualification methods.

Tables 3.7.2-23, 24 and 25 in the FSAR respectively provide SSI analysis results for one particular example shell, beam, and solid element, respectively. However, analysis results at other key locations are not provided. The applicant is requested to provide the design-basis seismic demands (e.g., forces, moments, soil pressures, accelerations, displacements, ISRS), at all applicable critical section locations of the RXB and CRB, that are used in structural design evaluations in FSAR Sections 3.8.4 and 3.8.5.

1) Provide the design-basis seismic demands, at all applicable critical section locations of the RXB and CRB. The forces, displacements, soil pressures, and ISRS will be computed according to NRC RG's, SRP's and DSRS (using the approaches outlined in FSAR Section 3.8.4 and 3.8.5). ACI 349-06 provides acceptance criteria for displacements in concrete structures.

2) Tables 3.7.2-23, 24 and 25 will be revised or a new table will be provided.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 10 8963 03.08.05-6 Section 3.8.4.1, the basemat reinforcement pattern of the foundation of RXB. However, the applicant did not provide sufficient information for the design assessments, boundary conditions for each foundation model, settlement evaluation and associated figures. Provide for the RXB basemat:

- design assessments-should include: the capacity of sections, design checks, etc.

- boundary conditions for each foundation model -should include: stiffness types and parameter throughout the embedded portion of the RXB for each type of model (standalone and combined) - SASSI2010, SAP2000, and ANSYS --

- settlement evaluations and figures showing reinforcement patters for (a) the entire RXB basemat, (b) intersections between walls & the RXB basemat, and (c) intersections between pilasters & the RXB basemat. Settlement evaluation should include following types of settlements: (1) Maximum vertical settlements, (2) tilt settlement, (3) differential settlement between structures and (4) angular distortion.

NuScale will provide, through the RAI response, additional information to supplement the design of the RXB and CRB basemat. The information will be tabulated to support design assessments, and will include design capacity, forces and moments at critical sections. In addition, a full description of analysis and boundary conditions will be provided for each model to demonstrate compliance with DSRS Section 3.8.5.II.4.N. To support the response:

1. Triple Building Differential Settlement calculation will be revised to include the capacity of sections, forces & moments at critical locations, settlement evaluation, and additional boundary conditions.

2. The additional informaiton will be reviewed, organized and tabulated to support design assessments.

Tier 2 Section 3.8.5.4.1 of the FSAR will be supplemented with additional descriptions of the basemat foundation analyses including boundary conditions and settlement evaluations. The additional information provided in tabular format for the design assessments of the foundations will be added to Appendix 3B of the FSAR.

12/20/2018 11 8971 03.08.04-11 While the magnitude of bounding demand forces and moments were provided for some critical sections (e.g. FSAR Tables 3B-36 to 3B-38), the FSAR did not provide the magnitudes of bounding demand forces and moments for all critical sections identified for the RXB and CRB. Provide in the FSAR the magnitude of bounding demand forces and moments for all critical sections, with a breakdown of seismic and static forces and moments.

Additionally, provide a numerical example that demonstrates how the direction of dynamic forces and moments is addressed in the load combinations as to ensure that the direction that is most adverse in a load combination has been considered as indicated in FSAR Section 3B.1.1.2.

Critical sections are defined as parts of the structure that: (1) perform a safety-critical function, (2) are subjected to large stress demands, (3) are considered difficult to design or construct, or (4) are considered to be representative of the structural design. These critical sections are listed in Appendix 3B of the FSAR. Static and dynamic structural responses obtained from SAP2000 and SASSI2010 analyses will be have been utilized to develop demand forces and moments such as static compression (negative) or tension (positive) membrane forces for walls and slabs.

Results of the SASSI2010 soil-structure interaction analysis which is used to analyze seismic loads will contain dynamic force and moments which are dependent of the direction of the seismic load applied to the structure. The direction resulting in most adverse load combination is considered for structural design. The presentation in the already completed calculations will be revised to more clearly show the magnitudes of bounding demand forces and moments for all critical sections.

To show how the effect of the direction of the seismic loads is considered in the design, an example will be provided that demonstrates that the most adverse direction in a load combination has been considered. In addition, a breakdown of static and seismic forces will be prepared and presented. Finally, FSAR Section 3.8.4 and Appendix 3B will be revised to include the details of the above research.

In summary,

1) Revise the calculations to include the magnitudes of bounding demand forces and moments for all critical sections;

2) Include a breakdown of seismic and static forces and moments;

3) Develop an example to demonstrate that the most adverse direction in a load combination has been considered; and

4) Update the FSAR Section 3.8.4 and Appendix 3B and include the results of the above research.

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NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 12 8974 03.08.04-20 10 CFR 50, Appendix A, GDC 1, 2, and 4 provides requirements to be met by SSC important to safety. In accordance with these requirements, DSRS Section 3.8.4 provides review guidance pertaining to the design of important to safety seismic Category I structures, other than the containment.

Consistent with DSRS Section 3.8.4, the staff reviews, in part, loads and loading combinations.

Provide the magnitude of bounding seismic design forces of the roof in the three orthogonal directions (North-South, East-West, and Vertical).

1) The magnitude of bounding seismic design forces of the roof in the three orthogonal directions will be provided, consistent with DSRS Section 3.8.4.

The following approach will be taken to address the response:

- Revise the already completed calculations for RXB SSI and CRB SSI to more clearly present the magnitude of bounding seismic design forces of the roof in the three orthogonal directions.

- A table, showing the bounding forces, will be added to FSAR Section 3.8.4 12/20/2018 LO-1018-62277 Page 8 of 13 NuScale Nonproprietary Page 8 of 13

NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 13 8911 03.09.02-43 TR-0916-51502-P, Rev. 0, Section 8.4.3 states that maximum uplift displacements of the NPM were calculated for each of the six analysis runs.

The maximum uplift occurred in the run representing the Capitola time history, soil type 7, with cracked RXB concrete, on the NPM in operating bay 6 with a nominal stiffness. As stated in Section 8.0, for the cracked RXB concrete case, two NPM stiffness were considered. Section 7.4 of the report states that uncertainty in the input and assumptions used in the finite element models of the NPM is accounted for by considering multiple analyses using +/-30 percent variations of the stiffness properties of the model. Therefore, in calculation of the maximum NPM uplift, the NRC staff considers that the case of 130% of the NPM stiffness for the cracked RXB concrete case should be considered. Increasing the NPM stiffness may bring the NPM dominant frequency closer to the cracked RXB frequency. The results of 77% NPM stiffness could be non-conservative. The applicant is requested to provide the maximum NPM uplift in the cracked RXB concrete case with an adjustment of +30 percent variation of the NPM stiffness (i.e.,

130% NPM stiffness). Alternatively, provide justification for not performing a cracked RXB concrete case with 130% of the NPM stiffness. Include the requested information in the NPM Seismic Report or in separate reports.

NuScale will perform new seismic runs including the cases requested in this RAI. In addition, NuScale will rerun the cases already provided. All new runs incorporate an enhanced methodology for modeling hydrodynamic mass in the pool area; this modeling uses harmonic analysis, modal analysis, and hand calculations to determine the hydrodynamic loading for the bay walls, walls in the refueling area, and the pool walls and floor, respectively. The new hydrodynamic mass along with the 12 detailed NPM beam models have been incorporated into the RXB SAP2000 model, and subsequently the cracked and uncraked RXB SASSI models. The updated SASSI models have been run with Soil Type 7, at 4% structural damping using the CSDRS compatible-Capitola time history to generate in-structure time histories in the pool area and RXB ISRS. Those time histories are used for NPM anlaysis. The complete set analysis results will be used to revise the seismic technical report.

In addition, ISRS for select locations in the RXB will be developed and checked against previously developed RXB ISRS in the FSAR. Any ISRS exceedances will be incorporated and will be revised in the FSAR. SASSI runs will also be made with Soil Type 7, at 7% concrete damping using the CSDRS compatible-Capitola time history to develop forces and moments, and those too will be checked against previously calculated demand.

The response will be provided by the specified due date.

NRC feedback, received 10/23, will be addressed in the RAI response, except for the comparison of the RFT support loads. The following items will be addressed:

1. Listing the six SASSI analysis cases that are used in the NPM seismic analysis.

2. Description of the enhanced method of modeling the hydrodynamic mass and determining the hydrodynamic load for bay walls, walls in the refueling area, pool walls and floor.

12/21/2018

3. Comparison of the NPM support loads obtained from the new analyses (SASSI and ANSYS 3D NPM) with the corresponding support loads used for the design of the NPM supports.

4. Comparison of the hydrodynamic pressures obtained from the new analyses (SASSI and ANSYS 3D NPM) with the corresponding pressure loads used for the design of the pool walls and floor.

5. The final response spectra corresponding to the seismic input for the NPM seismic analysis (including the case when the lower RPV is in the RFT)

6. Updating FSAR markups pertaining to Sections 3.7 and 3.8 that are impacted by new or re-analyses performed under this Closure Plan.

LO-1018-62277 Page 9 of 13 NuScale Nonproprietary Page 9 of 13

NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question#

RAI Question Plan Schedule 14 8911 03.09.02-45 TR-0916-51502-P, Rev. 0, Appendix C, Table C-1 (Summary of NuScale Power Module Component Interfaces) states that the reflector blocks and lower core plate are stacked and restrained in the horizontal direction with alignment pins. The reflector blocks and lower core plate are not restrained in the vertical direction other than by gravity. Tolerances and deformation between the mating parts allow some sliding to take place between parts. On the interface between the upper riser and lower riser, Table C-1 states that the lower riser conical section seats within the upper riser conical section.

There are tolerances between the two interfacing components allowing them to pitch slightly. The upper riser is not restrained in the vertical direction other than by gravity and compression of the bellows which keeps the interface closed. The description is insufficient for staff to reach a safety finding. The applicant is requested to provide the following information:

1. Figure B-18 (vertical ISRS at top of the lower core plate) indicates that the maximum vertical acceleration at top of the lower core plate is about 1.6 g (i.e., spectral acceleration at the high frequency end of the ISRS) that exceeds gravity acceleration. Provide a discussion on the possibility of uplift between the reflector blocks as well as between the reflector blocks and the lower core plate under the maximum vertical acceleration and their consequence.

2. Provide the vertical ISRS and the maximum vertical acceleration at the interface between the upper riser and the lower riser. Provide a discussion on the possibility of uplift of the upper riser from the lower riser under the maximum vertical acceleration and their consequence.

Include the requested information in the NPM Seismic Report.

Reflector Blocks/Lower Core Plate design Appendix C has been removed in TR-0916-51502-P, Rev. 1

1. In the NPM detailed 3D ANSYS model used for time history analysis, the reflector blocks have been modeled separate from the rest of the lower RVI. This model accounts for potential uplift, and will be was documented in the upcoming release with the recent submittal of TR-0916-51502 Revision 1 (NuScale letter LO-0918-61887, September 28, 2018). The maximum uplift between the 1st block and the lower core plate was determined to be ((2(a),(c) (TR Table 8-9). This amount of uplift (and associated calculated impact force of (( }}2(a),(c) (TR Table 8-8) produces an increased vertical response spectrum for the lower core plate in the range from (( }}2(a),(c)

(TR Figure B-21). Following the upcoming revision to the seismic input motions (which account for changes to the hydrodynamic mass applied to the pool walls, and are planned to be documented in TR-0916-51502 Revision 2) the impact of the change on the fuel will be evaluated to determine if the fuel is still bounded by existing margins or the scope of work required to establish new margins.

2. In the NPM detailed 3D ANSYS model, the upper and lower risers are not coupled in the vertical direction. The maximum relative displacement between the upper and lower risers is captured by the outputs of the NPM detailed 3D ANSYS transient analysis, and is are currently taken as (( }}2(a),(c). After the analysis is redone with the new seismic input motions that account for changes to the hydrodynamic mass applied to the pool walls, uplift of the upper riser from the lower riser will be shown to be negligible using a hand calculation for the impact force of the upper riser on the lower riser given the maximum relative displacement between the two.

12/21/2018 Alternatively, provide testing data to justify the use of 7% damping for RVI, RPV, containment, and NPM system damping or add an ITAAC to measure the as-built RVI components, RPV, containment, and NuScale power module system damping. Include the requested information in the NPM Seismic Report. LO-1018-62277 Page 10 of 13 NuScale Nonproprietary Page 10 of 13

NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question# RAI Question Plan Schedule 15 9225 04.02-8 In RAI 8769 Question 1, the staff requested information regarding fuel assembly structural response when in approved locations outside of an operating bay. As part of its response to this question, NuScale provided a Table which compared upper core plate motions when the fuel is located in the RFT as compared with the motions when the fuel was located in an operating bay. While the results indicate that the upper core plate motions in an operating bay bound those found when the fuel is located in the RFT, the staff notes that the RFT design is not currently finalized, as indicated by staff RAI 8838. Therefore, the staff does not consider Table 1 of the response to RAI 8769 Question 1 to be final. Update the core plate motions provided in the response to RAI 8769 Question 1 Table 1 with values derived from a final RFT design, or provide justification to explain how the values presented are bounding for all potential RFT designs. eRAI 9225 will provide core plate accelerations in the RFT after completion of new analysis. RAI 9225 requires analysis of the fuel in the RFT. The seismic analysis of the NuScale Power Module (NPM) is being re-performed this fall and is expected to complete by December 14th, 2018 October 26, 2018. The analysis will define core plate motions that will be ready for Framatome to evaluate for impact on the fuel by November 28th. If the core plate motion results are bounded by the current fuel seismic analysis of record, FRAMATOME will not need to perform a re-analysis of the fuel. In this scenario, the response to RAI 9225 could be submitted in early January of 2019. The schedule for 9225 has been developed assuming the seismic results are not bounded, would result in Framatome performing a fuel analysis that would take about 4 months to complete. 4/26/2019 LO-1018-62277 Page 11 of 13 NuScale Nonproprietary Page 11 of 13

NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question# RAI Question Plan Schedule 16 8838 03.08.04-1 Title 10 of the Code of Federal Regulations, Part 50, Appendix A, Criterion requires, in part, that SSCs important to safety are designed to withstand the effects of earthquakes without the loss of capability to perform their safety functions. The design bases for these SSCs shall reflect: (1) the severity of the historical reports, with sufficient margin to cover the limited accuracy, quantity, and time period for the accumulated data, (2) appropriate combinations of the effects of normal and accident conditions with the effects of the natural phenomena, and (3) the importance of the safety functions to be performed. DSRS Sections 3.7.2 and 3.8.4 provide review guidance pertaining to the seismic analysis, including interaction of the nonseismic Category I structures with seismic Category I SSCs, and structural design, including consideration of seismic loads, respectively. FSAR Section 9.1.5.2.3 describes refueling operations including, in part: (1) the placement and restraining of a bioshield on an adjacent bioshield; (2) the use of a containment vessel (CNV) flange tool (CFT) and reactor vessel (RPV) flange tool (RFT) for de-tensioning flange closure bolts and as structural supports during refueling operations; and (3) the placement of the upper CNV with the upper RPV still attached on the module inspection rack in the flooded dry dock. To assist the staff in evaluating the compliance of the aforementioned components with the above regulatory requirements the staff request the applicant to provide the following information and include these information in the FSAR (Sections 3.7 and 3.8, as applicable). Initial response submitted 7/5/2018 Errors have been identified, by NuScale, in both the seismic analysis and stress analysis of the RFT. The errors relate to boundary conditions used in both of the analyses, and the magnitude of the applied seismic load in the stress analysis. NuScale has started to evaulate alternate designs required to resolve the RFT design issues. The supplemental RAI response that discusses the RFT analysis will be delayed until the issues are resolved. NuScale will provide NRC a closure plan for this issue in November 2018. November 2018 Describe the method/mechanism for restraining a bioshield mounted on an adjacent bioshield and restraining the upper CNV on the module inspection rack during the refueling operations. Further, provide analysis and design criteria (consistent with DSRS Section 3.7.2.II.8) to ensure no adverse interactions occur between the seismic Category II bioshields and inspection racks with adjacent seismic Category I SSCs, during refueling operations (and during the transport of new modules, as applicable). For the seismic Category II CFT, a description of the CFT geometry, weight (with and without the lower CNV), structural materials, separation distance between the CFT and the RFT and surrounding walls, connection to the basemat, and analysis and design criteria (consistent with DSRS Section 3.7.2.II.8) to ensure no adverse interactions occur between the CFT and adjacent seismic Category I SSCs during refueling operations. For the seismic Category I RFT, design information including geometry, weight (with and without the RPV lower head), separation distance between RFT and surrounding walls, connection to the basemat, applicable design codes, standards, and specifications, design and analysis procedures, structural acceptance criteria, materials, quality control, special construction techniques (as applicable) and quality assurance requirements, testing and inservice surveillance programs, and ITAAC (as applicable). LO-1018-62277 Page 12 of 13 NuScale Nonproprietary Page 12 of 13

NuScale Closure Plan for FSAR Sections 3.7 and 3.8 RAIs - 10/30/2018 With Interfacing RAI Status eRAI Question# RAI Question Plan Schedule 8838 cont. Further, provide the seismic input (ISRS and acceleration time histories) at the base of the RFT, and at lower and upper core plate (if any) elevations while mounted on the RFT. Additionally, provide a description of how the seismic input motion is transferred from the RFT base elevation to the lower and upper core plate (if any) elevations. NRC Feedback: With respect to the CFT, the response indicates that design specifications have been prepared that establish the design criteria for the SC II CFT that address II/I design requirements. The staff request the applicant to provide a summary in the FSAR addressing the design criteria and II/I requirements for the CFT. With respect to the RFT, clarify whether the structural acceptance criteria for the RFT stand is also applicable to the embedded plate or if different, provide the structural acceptance criteria for the embedded plate. Further, clarify whether the embedded plate is made of 304L stainless steel or if different, indicate the embedded plate material. Describe how the embedded plate is anchored to the pool basemat. Describe the specific loads and load combinations used in the analysis and design of the RFT tool. Describe the seismic analysis case (s) considered in the analysis and design of the RFT. Describe the type of analysis performed (e.g. static, dynamic - response spectrum or time history analysis), analysis software used, and input properties such as damping, cracked/uncrack concrete properties (if any), as applicable. Update FSAR markups, as necessary to address the above information. Provide a summary of results for the RFT stand and embedded plate in the FSAR such as demand, capacity/allowable limits, and associated demand over capacity ratios. Provide FSAR figures addressing the RFT stand and embedded plate analysis model and RFT stand and embedded plate design including dimensions (e.g. plates, bolts, welds, concrete anchors, etc) and materials. Also, address the RFT analysis case (s) in FSAR Tables 3.7.2-34 and 3.7.2-35. Further, clarify whether the RFT is covered in the RXB ITAAC or other ITAAC, as applicable. Additionally, clarify how the weights associated with both the RFT and CFT have been considered in the analysis/design of the RXB basemat. LO-1018-62277 Page 13 of 13 NuScale Nonproprietary Page 13 of 13

LO-1018-62277 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 Zackary W. Rad, AF-1018-62347

AF-1018-62347 Page 1 of 2

NuScale Power, LLC AFFIDAVIT of Zackary W. Rad I, Zackary W. Rad, 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 report reveals distinguishing aspects about the NuScale Power Module seismic analysis. NuScale has performed significant research and evaluation to develop this analysis 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 Closure Plan for FSAR Sections 3.7 and 3.8 RAIs. 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 Nu Scale, 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 Nu Scale'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 Nu Scale 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 29, 2018. AF-1018-62347 Page 2 of 2}}