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Enclosunuscale CIRLT-RAI 9474
	ML18220A874
Person / Time
Site:	NuScale
Issue date:	07/25/2018
From:	Harris S; NuScale
To:	; Office of New Reactors
Shared Package
ML18220A872	List: ML18220A873; ML18220A874;
References
	LO-0718-61173 PM-0718-61172, Rev. 0
	Download: ML18220A874 (10)
	v • d • e

L0-0718-61173

Enclosure:

"NuScale CIRLT-RAI 9474," PM-0718-61172 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360-0500 Fax 541.207.3928 www.nuscalepower.com

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Agenda

Recap of proposed RAI response

- Preservice Design Pressure Leakage Test

- CNV flange analysis

- ITAAC

- Response summary

Refueling Overview (video)

Closed Session (proprietary)

- Screenshots of flange analysis model

- Additional slides for refueling discussion if needed 2

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CILRT

10 CFR Part 50, Appendix J Testing

- Type A (vessel test at accident pressure - NuScale seeks exemption)

- Type B (containment penetrations)

- Type C (containment isolation valves)

In lieu of a Type A test, NuScale is proposing a preservice design pressure leakage test

Purpose:

Verify design of flange seals through leak test at design pressure 3

Preservice Design Pressure Leakage Test

Test Characteristics

- CNV assembled with all flanges in place

- Take place in factory or onsite (must be out of RXB pool)

- Test will use final design flanges, bolting material (with design preload), and design seals

- Test will be performed with water as the pressure medium (similar to hydrotest)

- Test occurs at containment design pressure 4

Preservice Design Pressure Leakage Test

Acceptance Criteria

- Design pressure must be held for a minimum of 10 minutes prior to start of inspection

- Pressure will be maintained at or above design pressure for the time needed to visually inspect each vessel flange for leakage past outer flange seal

- Successful test is no visible leakage at bolted connections

- Similar to code requirements for a hydrotest

Subsequent Modules

- Test may be modified so that upper and lower can be tested separately 5

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CNV Bolting Analysis

Updating the Containment Vessel Flange Bolting Calculation for new scope:

Add analysis to demonstrate that inner a-ring seal contact is maintained for all CNV bolted flanges when internal containment is at design pressure when considering accident thermal transient conditions

Add analysis to demonstrate that lifting and moving the module does not stress CNV bolted flanges in a manner that contributes to flange distortion or seal positioning that would create leakage

Add assessment to show results of testing under ambient temperature conditions 6

CNV Bolting Analysis

Models of the bottom, middle, and top of the CNV, similar to the CNV ultimate pressure integrity calc, are used. Each type of bolted flange connection is modeled

Stud, nuts, washers and threaded inserts are included in the mode with contact defined between the nuts-washers, washers-flange, and cover-flange

All bolted connection preloads are calculated with margin over minimum preload need to maintain a tight joint

Thermal transient analyzed to obtain temperature distribution through CNV for inadvertent RRV opening and eves injection line break transients

The design pressure will be applied with temperature occurring at the time of peak accident pressure.

I~ -

ITAAC 02.01.07

Design Commitment

- The CNV serves as an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment.

Inspections, Tests, Analyses

- A leakage test will be performed of the pressure containing or leakage-limiting boundaries, and CIVs.

Acceptance Criteria

- The leakage rate for local leak rate tests (Type B and Type C) for pressure containing or leakage-limiting boundaries and CIVs meets the requirements of 10 CFR Part 50, Appendix J.

This ITAAC will be modified to include Acceptance Criteria for the preservice leak test at design pressure, with clarifying details added to Tier 2, Section 14.3.

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Summary of RAI 9474 Response

Update to Technical Report to update leakage assessment program (TR-1116-51962)

Update FSAR 3.8.2.7

Update FSAR 6.2

Update Type A Test Exemption

Update ITAAC Table 2.1-4

Update Table 14.3-1 to match ITAAC

Submit responses to RAI 9474, Questions 06.02.06-22 through 06.02.06-26 9

ML18220A874

Text

Enclosure:

Purpose:

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