ML18121A460

SMR DC RAI - Request for Additional Information No. 455 Erai No. 9473 (15.02.06)

ML18121A460
Person / Time
Site:	NuScale
Issue date:	05/01/2018
From:	NRC
To:	NRC/NRO/DNRL/LB1
References
Download: ML18121A460 (3)

Text

NuScaleDCRaisPEm Resource From: Chowdhury, Prosanta Sent: Tuesday, May 1, 2018 4:37 PM To: Request for Additional Information Cc: Lee, Samuel; Cranston, Gregory; Franovich, Rani; Karas, Rebecca; Burja, Alexandra; NuScaleDCRaisPEm Resource

Subject:

Request for Additional Information No. 455 eRAI No. 9473 (15.02.06)

Attachments: Request for Additional Information No. 455 (eRAI No. 9473).pdf Attached please find NRC staffs request for additional information (RAI) concerning review of the NuScale Design Certification Application.

Please submit your technically correct and complete response within 60 days of the date of this RAI to the NRC Document Control Desk.

If you have any questions, please contact me.

Thank you.

Prosanta Chowdhury, Project Manager Licensing Branch 1 (NuScale)

Division of New Reactor Licensing Office of New Reactors U.S. Nuclear Regulatory Commission 301-415-1647 1

Hearing Identifier: NuScale_SMR_DC_RAI_Public Email Number: 486 Mail Envelope Properties (BN7PR09MB260990B484D37064E35B04679E810)

Subject:

Request for Additional Information No. 455 eRAI No. 9473 (15.02.06)

Sent Date: 5/1/2018 4:37:07 PM Received Date: 5/1/2018 4:37:15 PM From: Chowdhury, Prosanta Created By: Prosanta.Chowdhury@nrc.gov Recipients:

"Lee, Samuel" <Samuel.Lee@nrc.gov>

Tracking Status: None "Cranston, Gregory" <Gregory.Cranston@nrc.gov>

Tracking Status: None "Franovich, Rani" <Rani.Franovich@nrc.gov>

Tracking Status: None "Karas, Rebecca" <Rebecca.Karas@nrc.gov>

Tracking Status: None "Burja, Alexandra" <Alexandra.Burja@nrc.gov>

Tracking Status: None "NuScaleDCRaisPEm Resource" <NuScaleDCRaisPEm.Resource@nrc.gov>

Tracking Status: None "Request for Additional Information" <RAI@nuscalepower.com>

Tracking Status: None Post Office: BN7PR09MB2609.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 556 5/1/2018 4:37:15 PM Request for Additional Information No. 455 (eRAI No. 9473).pdf 72021 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Request for Additional Information No. 455 (eRAI No. 9473)

Issue Date: 05/01/2018 Application

Title:

NuScale Standard Design Certification 048 Operating Company: NuScale Power, LLC Docket No.52-048 Review Section: 15.02.06 - Loss of Non-Emergency AC Power to the Station Auxiliaries Application Section:

QUESTIONS 15.02.06-4 The transient and accident analyses in Final Safety Analysis Report (FSAR) Tier 2, Chapter 15 serve, in part, to demonstrate compliance with the general design criteria (GDC) in Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix A. GDC 15 requires that the reactor coolant system (RCS) and associated auxiliary, control, and protection systems shall be designed with sufficient margin to assure that the design conditions of the reactor coolant pressure boundary (RCPB) are not exceeded during any condition of normal operation, including anticipated operational occurrences (AOOs).

Design-Specific Review Standard (DSRS) for NuScale Small Modular Reactor Section 15.0, "IntroductionTransient and Accident Analyses," provides guidance for meeting the requirements of several NRC regulations, including GDC 15. DSRS Section 15.0 specifies that pressure in the reactor coolant and main steam systems should be maintained below 110 percent of the design values in accordance with the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code. Furthermore, DSRS Section 15.0 guides the reviewer to evaluate key plant parameters (e.g., core flow) considered in the safety evaluation.

The FSAR Section 15.2.6 analyses, and most FSAR Chapter 15 analyses, assume a biased-low initial RCS flow rate. This assumption appears conservative for the calculation of minimum critical heat flux ration (MCHFR), as reduced RCS flow would reduce heat transfer. However, the staff notes that a biased-low initial RCS flow rate may not lead to limiting pressure responses because of reduced heat transfer capability. For the FSAR Section 15.2.6 analyses and all other Chapter 15 analyses that challenge RCS and/or steam generator (SG) pressure, justify the use of a biased-low initial RCS flow rate for the limiting RCS and SG pressure cases, or alternatively, update the limiting pressure cases to use the most limiting RCS flow rate. Update any affected sections in FSAR Chapter 15 as appropriate based on the response to this request.