ML19207A274

LLC Response to NRC Request for Additional Information No. 386 (Erai No. 9316) on the NuScale Design Certification Application

ML19207A274
Person / Time
Site:	05200046
Issue date:	07/26/2019
From:	Rad Z NuScale
To:	Document Control Desk, Office of New Reactors
References
RAIO-0719-66443
Download: ML19207A274 (4)

Text

RAIO-0719-66443 July 26, 2019 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.

386 (eRAI No. 9316) on the NuScale Design Certification Application

REFERENCE:

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

386 (eRAI No. 9316)," dated March 13, 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 Enclosure to this letter contains NuScale's response to the following RAI Question from NRC eRAI No. 9316:

03.09.02-52 This letter and the enclosed response make no new regulatory commitments and no revisions to any existing regulatory commitments.

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

Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8H12 Samuel Lee, NRC, OWFN-8H12 Marieliz Vera, NRC, OWFN-8H12 : NuScale Response to NRC Request for Additional Information eRAI No. 9316 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-0719-66443 :

NuScale Response to NRC Request for Additional Information eRAI No. 9316 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.: 9316 Date of RAI Issue: 03/13/2018 NRC Question No.: 03.09.02-52 In the response to RAI 8884, Question 03.09.02-4, the staff finds that using pre-verified software like ANSYS does not ensure valid structural models have been developed. Meshing procedures and densities, boundary condition assumptions, and fluid loading effects all should be appropriate and conservative for a given model to be reasonable and bounding. Provide a summary of the SIET TF1 and TF2 testing results for staff review and address any impacts of the results on SG FIV evaluations, wear, and fatigue life. Alternatively, NuScale may propose other options to resolve the staffs concerns. Without the validation of finite element modelling procedures and assessment of the overall modelling approach, the staff cannot reach a reasonable assurance finding on the structural integrity of the reactor internals components to withstand the adverse effects of vibration because finite element modelling procedures and the overall FIV modelling approach have not been demonstrated to be conservative, and as such could lead to failure of the reactor vessel internals. Add a summary of the information and any key conclusions regarding SG FIV to the comprehensive vibration assessment (CVAP) report TR-0716-50439.

NuScale Response:

The TF-1 and TF-2 test results were provided for review during NRC audits and are summarized in Section 3.0 of the NuScale Comprehensive Vibration Assessment Program (CVAP) Measurement and Inspection Plan technical report, TR-0918-60894. The selection of mesh size for the Steam Generator (SG) structural model is justified through mesh sensitivity studies that indicate that the selected mesh size is appropriate for the frequency range of interest. See Section 3.2.1.10 of TR-0918-60894 for the details of the mesh refinement study for the TF-2 structural model, and Section 5.1.2.6 of TR-0918-60894 for the TF-3 structural model NuScale Nonproprietary

mesh sensitivity analysis. As part of the pre-verified status of the ANSYS software, software test cases for modal analysis were validated against known solutions for common geometries, using a variety of element types and boundary conditions.

The performance of mesh sensitivity studies and test cases ensure that ANSYS is providing reasonable outputs for the given inputs. The methodology for selecting the mesh densities, boundary conditions, and fluid loading is to be validated against the TF-3 test results. The boundary conditions used in the current design analysis have been informed by preliminary testing at the TF-3 facility to provide the most prototypic results possible at this time. The mesh sensitivity performed for the design analysis SG structural model is discussed in Section 3.1.1 of the NuScale CVAP Analysis Technical Report, TR-0716-50439. Discussion of the TF-3 test plan and how the results are to be used to validate the design analysis are described in Section 5.1 of TR-0918-60894.

Impact on DCA:

The CVAP Measurement and Inspection Plan Technical Report TR-0918-60894 and the CVAP Analysis Technical Report TR-0716-50439 will be revised as described in the response above.

The technical reports are being submitted separately.

NuScale Nonproprietary