ML17252A688

2017/09/09 Nuscale SMR TR RAIs - Request for Additional Information Letter No. 9086 (Erai No. 9086) Topical Report Thermal Hydraulic Design

ML17252A688
Person / Time
Site:	PROJ0769
Issue date:	09/09/2017
From:	NRC
To:	NRC/NRO/DNRL/LB1
References
Download: ML17252A688 (3)

Text

1 NuScaleTRRaisPEm Resource From: Cranston, Gregory Sent: Saturday, September 09, 2017 12:40 PM To: RAI@nuscalepower.com Cc: NuScaleTRRaisPEm Resource; Lee, Samuel; Haider, Syed; Karas, Rebecca; Schmidt, Jeffrey; Chowdhury, Prosanta; Bavol, Bruce

Subject:

Request for Additional Information Lett er No. 9086 (eRAI No. 9086) Topical Report Thermal Hydraulic Design Attachments:

Request for Additional Inform ation No. 9086 (eRAI No. 9086).pdf Attached please find NRC staff's request for additional information concerning review of the NuScale Topical Report.

Please submit your 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.

Hearing Identifier: NuScale_SMR_DC_TR_Public Email Number: 52 Mail Envelope Properties (e6322d02ff224cf182e62809e6914116)

Subject:

Request for Additional Information Letter No. 9086 (eRAI No. 9086) Topical Report Thermal Hydraulic Design Sent Date: 9/9/2017 12:40:06 PM Received Date: 9/9/2017 12:40:09 PM From: Cranston, Gregory Created By: Gregory.Cranston@nrc.gov Recipients: "NuScaleTRRaisPEm Resource" <NuScaleTRRaisPEm.Resource@nrc.gov> Tracking Status: None "Lee, Samuel" <Samuel.Lee@nrc.gov> Tracking Status: None "Haider, Syed" <Syed.Haider@nrc.gov>

Tracking Status: None "Karas, Rebecca" <Rebecca.Karas@nrc.gov> Tracking Status: None "Schmidt, Jeffrey" <Jeffrey.Schmidt2@nrc.gov> Tracking Status: None "Chowdhury, Prosanta" <Prosanta.Chowdhury@nrc.gov> Tracking Status: None "Bavol, Bruce" <Bruce.Bavol@nrc.gov> Tracking Status: None "RAI@nuscalepower.com" <RAI@nuscalepower.com> Tracking Status: None Post Office: HQPWMSMRS07.nrc.gov Files Size Date & Time MESSAGE 305 9/9/2017 12:40:09 PM Request for Additional Information No. 9086 (eRAI No. 9086).pdf 90497

Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date: Recipients Received:

Request for Additional Information No. 9086 (eRAI No. 9086)

Issue Date: 09/09/2017 Application Title: NuScale Topical Report Operating Company: NuScale Docket No. PROJ0769 Review Section: 04.04 - Thermal and Hydraulic Design Application Section: 4.4 QUESTIONS 04.04-11 General Design Criterion (GDC) 10, "Reactor design" of Appendix A, "General Design Criteria for Nuclear Power Plants," to 10 CFR Part 50 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 operatio n, including the effects of anticipated operational occurrences (AOOs). NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition", Section 4.4, "Thermal and Hydraulic Design," stipulates the staff's review process for thermal and hydraulic design applications. One of the acceptance criteria specified in SRP Section 4.4 for the evaluation of fuel design limits is to ensure that the hot fuel rod in the core does not experience departure from nucleate boiling (DNB) during normal operation or AOOs. GDC 10 is relevant to the DNB as it is used to establish safety-related margins for the fuel and cladding integrity. To meet the requirements of GDC 10, as they relate to using a subchannel analysis methodology for determining the thermal margin available for the fuel design in steady-state and transient events, the applicant's met hodology should clearly justify the modeling assumptions.

In the NuScale subchannel analysis methodology topical report, Section 3.6, "Fuel Design

-Specific Inputs," the applicant states that the justification for using the grid loss coefficient smearing approach is provided by a parametric sensitivity analysis in Section 6.3, which demonstrates that the impact of the grid loss coefficients applied globally is negligible. Upon further review, the staff cannot locate this justification in Section 6.3 of the topical report. Based on the docketed information, the staff is unable to conclude whether the applicant's modeling methodology for the subchannel grid loss coefficient is adequate for determining thermal mar gin and thus meeting GDC 10. The staff requests the applicant to provide additional information in the topical report justifying th e approach used for the subchannel grid loss coefficient as described in Section 3.6 of the topical report.