ML18101B395

SMR DC RAI - Request for Additional Information No. 417 Erai No. 9442 (05.04.07)

ML18101B395
Person / Time
Site:	NuScale
Issue date:	04/11/2018
From:	NRC
To:	NRC/NRO/DNRL/LB1
References
Download: ML18101B395 (3)

Text

NuScaleDCRaisPEm Resource From: Chowdhury, Prosanta Sent: Wednesday, April 11, 2018 4:31 PM To: Request for Additional Information Cc: Lee, Samuel; Cranston, Gregory; Bavol, Bruce; Karas, Rebecca; Travis, Boyce; NuScaleDCRaisPEm Resource

Subject:

Request for Additional Information No. 417 eRAI No. 9442 (05.04.07)

Attachments: Request for Additional Information No. 417 (eRAI No. 9442).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: 448 Mail Envelope Properties (BN7PR09MB26097894A1B5075CE29F725E9EBD0)

Subject:

Request for Additional Information No. 417 eRAI No. 9442 (05.04.07)

Sent Date: 4/11/2018 4:30:43 PM Received Date: 4/11/2018 4:30:48 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 "Bavol, Bruce" <Bruce.Bavol@nrc.gov>

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

Tracking Status: None "Travis, Boyce" <Boyce.Travis@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 4/11/2018 4:30:48 PM Request for Additional Information No. 417 (eRAI No. 9442).pdf 11846 Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

Recipients Received:

Request for Additional Information No. 417 (eRAI No. 9442)

Issue Date: 04/11/2018 Application

Title:

NuScale Standard Design Certification 048 Operating Company: NuScale Power, LLC Docket No.52-048 Review Section: 05.04.07 - Residual Heat Removal (RHR) System Application Section: 5.4.3 QUESTIONS 05.04.07-6 10 CFR Part 50, Appendix A, GDC 34 requires in part that a system have the capability to transfer heat from the reactor such that fuel and pressure boundary design limits are not exceeded; this requirement is reflected in NuScale's PDC 34. For the NuScale design, the decay heat removal system (DHRS) serves this function.

FSAR Tier 2, Section 5.4.3.1 states that the design basis for the DHRS is to "remove post-reactor trip residual and core decay heat from operating conditions". During the course of interactions with NuScale regarding the return to power scenario as part of FSAR Section 15.0.6, NuScale has stated that the DHRS would be relied on for core cooling in the event of a select set of transient conditions involving a stuck rod. Such a scenario involves the DHRS removing core fission power, which is outside the design basis described in FSAR Section 5.4.3. Therefore, staff requests the applicant update the design basis description in Section 5.4.3.1 for the DHRS to include all scenarios for which DHRS is relied on to remove heat and/or core power. Additionally staff requests that the applicant provide a discussion somewhere in Section 5.4.3 describing the DHRS function during a return to power scenario, and either provide an appropriate system performance curve for the event (e.g. FSAR Figures 5.4.-13/14 and -15/16) or justify why the event is bounded by other design basis events. Further, staff requests that NuScale update PDC 34 to address fission power, or justify why PDC 34 adequately covers the existing design basis event spectrum.