ML23325A262
| ML23325A262 | |
| Person / Time | |
|---|---|
| Site: | 99902078 |
| Issue date: | 11/21/2023 |
| From: | Office of Nuclear Reactor Regulation |
| To: | NRC/NRR/DNRL/NRLB |
| References | |
| Download: ML23325A262 (5) | |
Text
From:
Getachew Tesfaye Sent:
Tuesday, November 21, 2023 5:53 PM To:
Request for Additional Information Cc:
Dennis Galvin; Mahmoud Jardaneh; Griffith, Thomas; Fairbanks, Elisa; NuScale-SDA-720RAIsPEm Resource
Subject:
Nonproprietary - NuScale SDAA Section 3.9.2 - Request for Additional Information No. 011 (RAI-10111-R1)
Attachments:
SECTION 3.9.2 - RAI-10111-R1-FINAL Non-Prop.pdf Attached please find NRC staffs nonproprietary request for additional information (RAI) concerning the review of NuScale Standard Design Approval Application for its US460 standard plant design (Agencywide Documents Access and Management System (ADAMS) Accession No. ML222339A066). The encrypted proprietary version will be submitted in a separate email.
Please submit your technically correct and complete response by the agreed upon date to the NRC Document Control Desk.
If you have any questions, please do not hesitate to contact me.
Thank you, Getachew Tesfaye (He/Him)
Senior Project Manager NRC/NRR/DNRL/NRLB 301-415-8013
Hearing Identifier:
NuScale_SDA720_RAI_Public Email Number:
19 Mail Envelope Properties (BY5PR09MB56822C1893F20E699AADB40F8CBBA)
Subject:
Nonproprietary - NuScale SDAA Section 3.9.2 - Request for Additional Information No. 011 (RAI-10111-R1)
Sent Date:
11/21/2023 5:53:19 PM Received Date:
11/21/2023 5:53:22 PM From:
Getachew Tesfaye Created By:
Getachew.Tesfaye@nrc.gov Recipients:
"Dennis Galvin" <Dennis.Galvin@nrc.gov>
Tracking Status: None "Mahmoud Jardaneh" <Mahmoud.Jardaneh@nrc.gov>
Tracking Status: None "Griffith, Thomas" <tgriffith@nuscalepower.com>
Tracking Status: None "Fairbanks, Elisa" <EFairbanks@nuscalepower.com>
Tracking Status: None "NuScale-SDA-720RAIsPEm Resource"
<NuScale-SDA-720RAIsPEm.Resource@usnrc.onmicrosoft.com>
Tracking Status: None "Request for Additional Information" <RAI@nuscalepower.com>
Tracking Status: None Post Office:
BY5PR09MB5682.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 674 11/21/2023 5:53:22 PM SECTION 3.9.2 - RAI-10111-R1-FINAL Non-Prop.pdf 154345 Options Priority:
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1 NONPROPRIETARY REQUEST FOR ADDITIONAL INFORMATION No. 011 (RAI-10111-R1)
BY THE OFFICE OF NUCLEAR REACTOR REGULATION NUSCALE STANDARD DESIGN APPROVAL APPLICATION DOCKET NO.
05200050 CHAPTER 3, DESIGN OF STRUCTURES, SYSTEMS, COMPONENTS AND EQUIPMENT SECTION 3.9.2, DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, COMPONENTS, AND EQUIPMENT ISSUE DATE: 11/21/2023
Background
By letter dated December 31, 2022, NuScale Power, LLC (NuScale or the applicant) submitted Part 2, Final Safety Analysis Report (FSAR), Chapter 3, Design of Structures, Systems, Components, and Equipment, Revision 0 (Agencywide Documents Access and Management System Accession No. ML23001A016) of the NuScale Standard Design Approval Application (SDAA) for its US460 standard plant design. The applicant submitted the US460 plant SDAA in accordance with the requirements of Title 10 of the Code of Federal Regulations (10 CFR) Part 52, Licenses, Certifications, and Approvals for Nuclear Power Plants, Subpart E, Standard Design Approvals. The NRC staff has reviewed the information on the dynamic analysis and testing provided in Chapter 3 of the SDAA and determined that additional information is required to complete its review.
Question 3.9.2-1 Regulatory Basis The NRC regulations in 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion 4, Environmental and Dynamic Effects Design Bases, require structures, systems, and components important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents.
Issue FSAR Appendix 3A.1, Seismic Analysis, references TR-121515, US460 NuScale Power Module Seismic Analysis, Revision 0, and Appendix 3A.2, Blowdown Simulation, references TR-121517, NuScale Power Module Short-Term Transient Analysis, Revision 0. TR-121515 describes the methodologies and structural models that are used to analyze the dynamic structural loading of reactor vessel internals (RVI) due to seismic loads acting on the NuScale power module-20 (NPM-20). TR-121517 describes methodologies and models that are used to analyze the transient loads within NPM-20 caused by failure or actuation of piping and valves. NPM-20 might be subjected to transient dynamic loads from various phenomena, including seismic events and transient events such as inadvertent valve openings.
2 FSAR Section 3.9.1, Special Topics for Mechanical Components states that core support structures will meet ASME Boiler and Pressure Vessel Code (BPV Code),Section III service level requirements, and in particular the Service Level C (transient events) and Service Level D (seismic events). These requirements include maximum allowable stresses. NuScale has not provided the ASME BPV Code,Section III, Service Level C or D assessments for RVI and SG tubes and supports for NPM-20. NuScale plans to complete final stress reports during inspection, test, analysis, and acceptance criteria (ITAAC) activities for NPM-20. The NRC staff needs to review the preliminary stress analyses to make a safety finding in the SDAA safety evaluation for NPM-20.
In NuScales supplemental information submitted to address Audit Question A-3.9.2-8 item 4 (ML23304A410), NuScale explained the discrepancy between the upper reactor vessel internal (URVI) and lower reactor vessel internal (LRVI) interface modeling and resulting differences between the low-order modes of the double building (DB) structural model and the detailed NPM-st 20 ructural model. (( The staff cannot agree with this conclusion without additional information, (( }} shown in the report and is concerned the modeling assumption may have led to non-conservative seismic loads in that frequency range. Requested Information 1. During the design certification application (DCA) review for NPM-160, NuScale submitted a detailed response to staff request for additional information (eRAI 8911, Question 09.02-18 in NuScale transmittal RAIO-0819-66530), which included ASME Service Level D stress assessments. NuScale is requested to provide information at a similar level of detail for seismic and transient loading of NPM-20, including the structural integrity of the control rod assembly guide tubes (CRAGT), in-core instrument guide tubes (ICIGT), and SG tubes and supports. The information should include the following: a brief description of the component modelling, applied input motion (time history or in-structure response spectrum, coherent incoherent loading at different mounting locations), major assumptions, acceptance criteria under Service Level C or D condition including deflection
- limits, fluid modelling, mass distribution, damping value(s),
gap considerations and potential contact with adjacent components and/or
- walls,
3 dominant modes of vibration and frequencies (show images of the mode shapes), stress convergence studies, stress concentration factors, and weld factors (if welds are at or near a limiting location) 2. To support the review of the seismic and transient loading for the SDAA safety evaluation for NPM-20, NuScale is also requested to provide the following information: Calculation results for radial deflections of the CRAGTs and ICIGT and assessments of the effects of impacts (if any) between the CRAGTs and ICIGT and the adjacent holes within the various support plates along the height of the riser. Quantitatively substantiate the statement that the DB modeling assumption at the URVI/LRVI interface does not lead to non-conservative bias results in the final seismic loading and dynamic response calculations. A comparison between loading calculations performed with and without the assumption corrected for a limiting condition is one option to substantiate NuScales conclusion.}}