ML18101B418

SMR DC RAI - Request for Additional Information No. 419 Erai No. 9502 (15)

ML18101B418
Person / Time
Site:	NuScale
Issue date:	04/11/2018
From:	NRC
To:	NRC/NRO/DNRL/LB1
References
Download: ML18101B418 (3)

Text

NuScaleDCRaisPEm Resource From: Chowdhury, Prosanta Sent: Wednesday, April 11, 2018 5:10 PM To: Request for Additional Information Cc: Lee, Samuel; Cranston, Gregory; Franovich, Rani; Karas, Rebecca; Schmidt, Jeffrey; NuScaleDCRaisPEm Resource

Subject:

Request for Additional Information No. 419 eRAI No. 9502 (15)

Attachments: Request for Additional Information No. 419 (eRAI No. 9502).pdf Attached please find NRC staffs request for additional information (RAI) concerning review of the NuScale Design Certification Application.

The NRC Staff recognizes that NuScale has preliminarily identified that the response to one or more questions in this RAI is likely to require greater than 60 days. NuScale is expected to provide a schedule for the RAI response by email within 14 days.

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: 450 Mail Envelope Properties (BN7PR09MB26099A53DD9BA1C23866FAEB9EBD0)

Subject:

Request for Additional Information No. 419 eRAI No. 9502 (15)

Sent Date: 4/11/2018 5:09:46 PM Received Date: 4/11/2018 5:09:51 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 "Schmidt, Jeffrey" <Jeffrey.Schmidt2@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 675 4/11/2018 5:09:51 PM Request for Additional Information No. 419 (eRAI No. 9502).pdf 26571 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Request for Additional Information No. 419 (eRAI No. 9502)

Issue Date: 04/11/2018 Application

Title:

NuScale Standard Design Certification 048 Operating Company: NuScale Power, LLC Docket No.52-048 Review Section: 15 - Introduction - Transient and Accident Analyses Application Section:

QUESTIONS 15-4 General Design Criterion (GDC) 10, "Reactor design," in Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Appendix A, requires that the reactor core and associated coolant, control, and protection systems shall be designed with appropriate margin to assure that specified acceptable fuel design limits (SAFDLs) are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences (AOOs).

To confirm whether margin to the SAFDLS is met for the Chapter 15 events, the staff needs to understand whether appropriate initiating events and single failures have been considered in the analyses.

Final Safety Analysis Report (FSAR) Section 15.0.0.6.6, Treatment of Non-safety-related systems, states that the application assumes the worst single failure of a control system unless the following conditions are met:

x a single failure in the nonsafety-related system does not impact DBEs.

x a detectable, non-coincident, random independent failure does not disable the system.

x the system is capable of functioning under the licensing assumptions for the event being analyzed.

The staff notes the non-loss of coolant accident (LOCA) topical report, TR-0516-49416, which is incorporated by reference into the FSAR, states, "...if operation of the control system leads to a less severe plant response, then the actions of the control system are not simulated for the transient of interest. Conversely, if operation of the control system causes the event consequences to be more severe, the [plant control system (PCS)] is assumed to operate as designed. Under no circumstances is the control system assumed to malfunction, since such an occurrence would be considered an initiating event."

The staff requests the applicant reconcile the apparent difference between FSAR Section 15.0.0.6.6 and the non-LOCA topical report and identify if any FSAR Section 15 events assume the worst possible failure of a control system. If FSAR Section 15.0.0.6.6 contains the appropriate language, the staff further requests how bullets two and three above are evaluated.