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LLC, Submittal of Presentation Materials Entitled SDAA Review Presentation on RPV Connections, PM-174304, Revision 0
	ML24269A024
Person / Time
Site:	05200050, 99902078
Issue date:	09/25/2024
From:	Shaver M; NuScale
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	LO-174305 PM-174304, Rev 0
	Download: ML24269A024 (1)
	v • d • e

LO-174305 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com September 25, 2024 Docket No. 052-050 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

SUBJECT:

NuScale Power, LLC Submittal of Presentation Materials Entitled SDAA Review Presentation on RPV Connections, PM-174304, Revision 0 The purpose of this submittal is to provide requested presentation material to the NRC presented during a Standard Design Approval Application audit meeting held May 7 & 8, 2024 related to Chapter 3 on the topic of bolted reactor pressure vessel (RPV) connections and regulatory acceptance criteria. Enclosure 1 to this letter provides the nonproprietary presentation materials PM-174304 entitled SDAA Review Presentation on RPV Connections.

This letter makes no regulatory commitments and no revisions to any existing regulatory commitments.

If you have any questions, please contact Elisa Fairbanks at 541-452-7872 or EFairbanks@nuscalepower.com.

I declare under penalty of perjury that the foregoing is true and correct. Executed on September 25, 2024.

Sincerely, Mark W. Shaver Director, Regulatory Affairs NuScale Power, LLC Distribution:

Mahmoud Jardaneh, Chief, New Reactor Licensing Branch, NRC Getachew Tesfaye, Senior Project Manager, NRC Prosanta Chowdhury, Senior Project Manager, NRC : SDAA Review Presentation on RPV Connections, PM-174304, Revision 0

LO-174305 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com SDAA Review Presentation on RPV Connections, PM-174304, Revision 0

NuScale Nonproprietary Template #: 0000-21727-F01 R10 SDAA Review Presentation on RPV Connections May 7, 2024 Daniel Lassiter, Daniel Diefendorf RCS Leakage Monitoring and Break Exclusion

NuScale Nonproprietary Template #: 0000-21727-F01 R10 Acknowledgement and Disclaimer This material is based upon work supported by the Department of Energy under Award Number DE-NE0008928.

This presentation was prepared as an account of work sponsored by an agency of the United States (U.S.)

Government. Neither the U.S. Government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the U.S. Government or any agency thereof.

NuScale Nonproprietary Template #: 0000-21727-F01 R10 RCS Leakage Detection and Monitoring Technical Specifications:

o RCS Leakage Detection Instrumentation o LCO 3.4.7

Two of the following RCS Leakage detection instrumentation methods shall be OPERABLE A) Two Containment Evacuation System (CES) condensate channels, B) Two CES inlet pressure channels, and C) One CES gaseous radioactivity monitor channel condensate NC gas

NuScale Nonproprietary Template #: 0000-21727-F01 R10 RCS Leakage Detection and Monitoring In accordance with RG 1.45 guidance (C.2.3), NuScale Technical Specifications identify at least two independent and diverse instruments and/or methods that have the detection and monitoring capabilities detailed in RG 1.45 positions C.2.1 and C.2.2:

o CES Condensate (sample vessel level) o CES Inlet Pressure CES radiation monitoring is a tertiary means of identifying RCS leakage but is not credited to meet the performance criteria detailed in RG 1.45 positions C.2.1 and C.2.2.

o Note - CVCS makeup history may provide additional information to operators about the source of observed leakage.

RG 1.45 (R1) content for reference:

o Position C.2.1

Plant procedures should include the collection of leakage to the primary reactor containment from unidentified sources so that the total flow rate can be detected, monitored, and quantified for flow rates greater than or equal to 0.05 gal/min.

o Position C.2.2

The plant should use leakage detection systems with a response time (not including the transport delay time) of no greater than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> for a leakage rate of 1 gal/min.

These instruments (CES Condensate, CES Inlet Pressure) are designed with accuracies necessary to achieve the RG 1.45 performance criteria.

NuScale Nonproprietary Template #: 0000-21727-F01 R10 RCS Leakage Detection and Monitoring Technical Specification leakage limits:

o RCS Operational LEAKAGE o LCO 3.4.5

RCS operational LEAKAGE shall be limited to:

A) No pressure boundary LEAKAGE B) 0.5 gpm unidentified LEAKAGE C) 2 gpm identified LEAKAGE from the RCS, and D) 150 gallons per day primary to secondary LEAKAGE As described in SDAA Section 5.2.5.1, it is expected that the plant will treat all leakage detected and monitored by CES to be unidentified because local means of leakage detection for individual pathways (e.g.

flanges, valves) are not provided.

Corrective actions for observed leakage exceeding these limits are required per Technical Specifications (up to and including shutting down the reactor)

NuScale Nonproprietary Template #: 0000-21727-F01 R10 RCS Leakage Detection and Monitoring For the US600 design, containment leakage monitoring systems were calculated to be sensitive to leak rates as low as 0.001 gpm in order to support leak-before-break (LBB) evaluations of the main steam and feedwater lines inside containment.

During the US600 DCA review, the NRC requested in DCA RAI 9358, Question 03.06.02-17, that NuScale describe Local leakage detection (potentially similar in concept to leakage detection from reactor vessel heads) that will provide indication of leakage before gross bolt failure, such that the plant can shut down.

NuScale responded by describing the extremely sensitive leakage detection capabilities and indicated that leakage from the flange would be expected to be larger than that from an LBB crack in a main steam or feedwater pipe. This provided justification that additional local leakage detection was not required for this connection.

LBB methodologies were not employed for the ECCS valve bolted connections in the US600 design.

The US460 design does not utilize LBB methodologies for the main steam and feedwater lines, and therefore the sensitivity requirements relaxed from 0.001 gallons per minute (gpm) in the DCA to 0.05 gpm in the SDAA.

This change is described in NuScales response to SDAA RAI 10135, Question 3.6.2.7-2.

NuScales position is that the capabilities of the leakage detection system described in the US460 SDAA meet the limits specified in RG 1.45 for the purpose of detecting degradation to the RCPB, including the ECCS flanged connections.

NuScale Nonproprietary Template #: 0000-21727-F01 R10 CES Containment Evacuation System DCA Design Certification Application LBB Leak-before-break LCO Limiting Condition of Operation LIT Level Indicating Transmitter PIT Pressure Indicating Transmitter RCS Reactor Coolant System RE Radiation Instrument SDAA Standard Design Approval Application SDA Standard Design Approval Acronyms

ML24269A024

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