Text

LLC Response to NRC Request for Additional Information No. 433 (Erai No. 9474) on the NuScale Design Certification Application
	ML18267A403
Person / Time
Site:	NuScale
Issue date:	09/24/2018
From:	Rad Z; NuScale
To:	; Document Control Desk, Office of New Reactors
References
	RAIO-0918-61923
	Download: ML18267A403 (143)
	v • d • e

September 24, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 RAIO-0918-61923 Docket No.52-048

SUBJECT:

NuScale Power, LLC Response to NRC Request for Additional Information No.

433 (eRAI No. 9474) on the NuScale Design Certification Application

REFERENCE:

U.S. Nuclear Regulatory Commission, "Request for Additional Information No.

433 (eRAI No. 9474)," dated April 23, 2018 The purpose of this letter is to provide the NuScale Power, LLC (NuScale) response to the referenced NRC Request for Additional Information (RAI).

The Enclosure to this letter contains NuScale's response to the following RAI Questions from NRC eRAI No. 9474:

06.02.06-22

06.02.06-23

06.02.06-24

06.02.06-25

06.02.06-26 This letter and the enclosed response make no new regulatory commitments and no revisions to any existing regulatory commitments.

If you have any questions on this response, please contact Marty Bryan at 541-452-7172 or at mbryan@nuscalepower.com.

Sincerely, Zackary W. Rad Director, Regulatory Affairs NuScale Power, LLC Distribution: Gregory Cranston, NRC, OWFN-8G9A Omid Tabatabai, NRC, OWFN-8G9A Samuel Lee, NRC, OWFN-8G9A : NuScale Response to NRC Request for Additional Information eRAI No. 9474 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com

RAIO-0918-61923 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvalis, Oregon 97330, Office: 541.360.0500, Fax: 541.207.3928 www.nuscalepower.com :

NuScale Response to NRC Request for Additional Information eRAI No. 9474

Response to Request for Additional Information Docket No.52-048 eRAI No.: 9474 Date of RAI Issue: 04/23/2018 NRC Question No.: 06.02.06-22 The regulatory bases for the question below are:

10 CFR 50.12 Specific Exemptions, (a)(1) The Commission maygrant exemptions from the requirements of the regulations which will not present an undue risk to the public health and safety.

10 CFR 52.47, Contents of Applications; technical information, (a) The application must contain a final safety analysis report (FSAR) that describes the facility, presents the design bases and the limits on its operation, and presents a safety analysis of the structures, systems, and components and of the facility as a whole, and must include the following information: (2) A description and analysis of the structures, systems, and components (SSCs) of the facility, with emphasis upon performance requirements, the bases, with technical justification therefor, upon which these requirements have been established, and the evaluations required to show that safety functions will be accomplished. The description shall be sufficient to permit understanding of the system designs and their relationship to the safety evaluations.

10 CFR 52.47 Contents of Applications; technical information, (a)(2)(iv) which states, in part "The applicant shall perform an evaluation and analysis of the postulated fission product release, using the expected demonstrable containment leak rate to evaluate the offsite radiological consequences."

10 CFR 50, GDC 16Containment design. Reactor containment and associated systems shall be provided to establish an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment and to assure that the containment design conditions important to safety are not exceeded for as long as postulated accident conditions require.

NuScale Nonproprietary

10 CFR 50, Appendix J, defines La as the maximum allowable containment leakage rate in weight percent per day at peak containment accident pressure, Pa. The combined leakage rate of all penetrations and valves subject to Type B and C tests shall be less than 0.60 La.

This is a followup to RAI 271-9147, question 6.2.6-4.

10 CFR 50, Appendix J, requires that primary reactor containments meet the containment leakage test requirements to provide for preoperational and periodic verification by tests of the leak-tight integrity of the primary reactor containment, and systems and components which penetrate containment.

NuScale, has selected La to be 0.20 weight percent of the containment air mass per day at the peak containment accident pressure, Pa. La is established as a safety analysis operational limit and the containment Technical Specification limit for operability for the NuScale design. This maximum allowed leakage rate is the basis for the accident radiological leakage to the environment.

NuScale is requested to describe how the maximum allowable leak rate, La, will be demonstrated. Typically this would be shown through a combination of preoperational and periodic Types A, B and C testing. Since NuScale has requested an exemption from Appendix J Type A test requirements, this demonstration should include the technical basis for concluding that Types B and C testing are sufficiently representative of accident conditions to provide confidence that the test results from Types B and C assure that the assumed leak rate, La, would not be exceeded. Additionally, as required by 10 CFR 50, Appendix J, the acceptance criteria for Types B and C tests is to show that the expected leakage from all local penetrations, Types B and C, is less than 0.60 La. This demonstration should consider the differences in test volume pressurization during Type A and Types B and C testing and their potential impact on the test results. For example, the stresses on a bolted connection would be significantly different during Type A testing, where the containment volume is held at accident pressure, than a Type B test, where only the volume between a double o-ring seal is pressurized.

NuScale Response:

Maximum allowable leak rate (La) demonstration:

The maximum allowable leak rate, La, will be demonstrated by Type B and Type C local leak rate testing (LLRT) as prescribed in 10 CFR 50 Appendix J with preoperation and inservice testing. LLRT acceptance criteria shall be maintained at 0.60La as required by Appendix J.

NuScale Nonproprietary

In lieu of a Type A integrated leak rate test NuScale produces the following stages of confirmation demonstrating containment flange leakage integrity: (1) NuScale has performed a containment flange bolting calculation that provides assurance that all containment flanges maintain contact pressure between the flanges from the inside seal to the vessel opening under peak accident conditions; (2) Each containment vessel (CNV) undergoes a preservice design pressure leakage test which tests CNV bolted flange connections with design bolt preload and at design pressure, prior to initial operation of the containment vessel. The test acceptance criteria is no observed leakage from any CNV bolted flange connection; (3) procedures are established to verify bolt preload and Type B testing is performed prior to the CNV going into operation to verify seal integrity. The containment flange bolting calculation, preservice design pressure leakage test, and flange preload verifications with Type B testing provide a basis for utilizing LLRT to demonstrate acceptable CNV leakage.

The CNV is an ASME Code Class 1 pressure vessel. The NuScale containment flange bolting calculation assumes that an internal pressure equal to or greater than the design pressure is applied to the inside of the containment vessel. The internal pressure is applied to two different accident conditions 1) CNV metal temperature associated with the inadvertent reactor recirculation valve (RRV) opening event at the time peak pressure occurs, which is the limiting containment peak pressure accident case; and, 2) CNV metal temperature associated with the CVCS injection line break event at the time peak pressure occurs, which results in a slightly lower containment pressure, but higher containment temperature. The bolted flange connections are evaluated for the contact pressure across the flange seal face.

The preliminary results of the containment flange bolting calculation determined that a small flange gap (< 0.010 inch) may have developed. Although the small gap would not have been expected to permit any leakage at accident pressure and temperature conditions, due to the expected spring back of the seal, NuScale has modified the flange design by adjusting the flange geometry to ensure better sealing and application of preload to the sealing face. With those modifications, the final containment flange bolting calculation demonstrates that each containment flange design and associated design bolting preload maintains flange contact pressure, and prevents flange leakage at accident temperature concurrent with peak accident pressure. The calculation also reveals that the preservice design pressure leakage test, at the uniform preservice design pressure leakage test temperature, is the bounding case for thermal and pressure effects on flange preload. The containment flange bolting calculation also evaluated the impact of lifting the CNV for repositioning back to the operating bay and the impact on the bolted joint. The calculation shows there is no significant change to joint load and that the joint will not open or loosen to create a change to the sealing of the flanged connection.

NuScale Nonproprietary

The flange modifications made to support this analysis improve the sealing capability of the flanges and therefore do not alter the conclusions of TR-0917-56119, CNV Ultimate Pressure Integrity, which serves to determine a lowest possible ultimate pressure using conservative assumptions.

Additionally, an ITAAC has been created for a preservice design pressure leakage test which verifies no observed water leakage from CNV bolted flange connections at CNV design pressure (refer to the response to eRAI 9474, Question 06.02.06-23). The test of the initial as-built containment vessel will be performed on an assembled containment vessel, using the as-designed flange covers installed with the design bolting materials, design bolting assembly preloads, and design seals installed. The upper and lower halves of subsequent containment vessels may be tested separately. Covers with electrical and instrumentation penetrations may be substituted with blank covers having the same bolting and sealing design as the inservice covers. The test configuration may utilize blanked off pipe ends in place of the containment isolation valves. This is acceptable because the Type C test for containment isolation valves pressurizes those components similarly to peak accident pressure conditions. The preservice design pressure leakage test will be performed with the containment vessel filled with water similar to a hydrostatic test. At design pressure, and a test temperature of a minimum of 70 degrees F and a maximum of 140 degrees F, a leakage check of CNV bolted flange connections is performed. The acceptance criterion is no observed leakage at examination pressure. A satisfactory leakage test confirms that the as-built containment vessel flanges do not develop any leakage paths under conditions which bound peak containment pressure accident conditions.

Each ECCS trip valve and reset valve contains a body-to-bonnet joint that is also subject to Type B test requirements. The body-to-bonnet seal is designed for RCS design pressure. This seal is tested to meet both Type B and RCPB criteria every refueling outage. These body-to-bonnet seals are not considered to be a flanged connection and are not included in the containment flange bolting calculation or preservice design pressure leakage test.

Impact of not performing a Type A test:

LLRT is relied on to determine the combined leakage from the containment system. The flange bolting calculation demonstrates that each containment flange design and associated design bolting preload maintains flange contact pressure and prevents flange leakage at accident temperature concurrent with peak pressure conditions. The preservice design pressure leakage test loads each of the CNV bolted flange connections at design pressure. Demonstrating no observed leakage during this test with the flanges stressed to above the peak accident pressure provides the basis for relying upon the Type B test to demonstrate flange leakage under NuScale Nonproprietary

accident conditions. Finally, containment flange bolting preload verification performed in the as-left condition confirms the flanges are assembled per design and the Type B testing quantifies any leakage which may occur past the flange seals. The combination of the containment flange bolting calculation, preservice design pressure leakage test, and flange preload verifications provide reasonable assurance that LLRT performed pursuant to Appendix J demonstrates that the containment system will perform its intended safety function under accident conditions.

New COL Item 6.2-2 requires a COL applicant that references the NuScale Power Plant design certification to verify the final design for their plant shall meet this requirement. (refer to the response to RAI 9474, Question 06.02.06-23).

Impact on DCA:

TIer 1 Section 2.6 and Tier 2 FSAR Sections 1.9, 3.8.2, 6.2.6, 14.3 and Part 7 and related technical report TR-1116-51692 have been revised as described in the response above and as shown in the markup provided with this response.

NuScale Nonproprietary

NuScale Tier 1 NuScale Power Module Tier 1 2.1-13 Draft Revision 2 RAI 06.02.06-22, RAI 06.02.06-23, RAI 08.01-1, RAI 08.01-1S1, RAI 08.01-2, RAI 14.03.03-3S1, RAI 14.03.03-4S1, RAI 14.03.03-6S1, RAI 14.03.03-7S1, RAI 14.03.03-8, RAI 14.03.03-11S1 Table 2.1-4: NuScale Power Module Inspections, Tests, Analyses, and Acceptance Criteria No.

Design Commitment Inspections, Tests, Analyses Acceptance Criteria 1.

The NuScale Power Module ASME Code Class 1, 2 and 3 piping systems listed in Table 2.1-1 comply with ASME Code Section III requirements.

An inspection will be performed of the NuScale Power Module ASME Code Class 1, 2 and 3 as-built piping system Design Reports required by ASME Code Section III.

The ASME Code Section III Design Reports (NCA-3550) exist and conclude that the for the NuScale Power Module ASME Code Class 1, 2 and 3 as-built piping systems listed in Table 2.1-1 meet the requirements of ASME Code Section III, NCA-3550.

2.

The NuScale Power Module ASME Code Class 1 and 2 components conform to the rules of construction of ASME Code Section III.

An inspection will be performed of the NuScale Power Module ASME Code Class 1 and 2 as-built component Data Reports required by ASME Code Section III.

ASME Code Section III Data Reports for the NuScale Power Module ASME Code Class 1 and 2 components listed in Table 2.1-2 and interconnecting piping exist and conclude that the requirements of ASME Code Section III are met.

3.

The NuScale Power Module ASME Code Class CS components conform to the rules of construction of ASME Code Section III.

An inspection will be performed of the NuScale Power Module ASME Code Class CS as-built component Data Reports required by ASME Code Section III.

ASME Code Section III Data Reports for the NuScale Power Module ASME Code Class CS components listed in Table 2.1-2 exist and conclude that the requirements of ASME Code Section III are met.

4.

Safety-related SSC are protected against the dynamic and environmental effects associated with postulated failures in high-and moderate-energy piping systems.

An inspection and analysis will be performed of the as-built high-and moderate-energy piping systems and protective features for the safety-related SSC.

Protective features are installed in accordance with the as-built Pipe Break Hazard Analysis Report and safety-related SSC are protected against or qualified to withstand the dynamic and environmental effects associated with postulated failures in high-and moderate-energy piping systems.

5.

The NuScale Power Module ASME Code Class 2 piping systems and interconnected equipment nozzles are evaluated for LBB.

An analysis will be performed of the ASME Code Class 2 as-built piping systems and interconnected equipment nozzles.

The as-built LBB analysis for the ASME Code Class 2 piping systems listed in Table 2.1-1 and interconnected equipment nozzles is bounded by the as-designed LBB analysis.

6.

The RPV beltline material has a Charpy upper-shelf energy of greater than 75 ft-lb minimum.

A vendor test will be performed of the Charpy V-Notch specimen of the RPV beltline material.

An ASME Code Certified Material Test Report exists and concludes that the initial RPV beltline material Charpy upper-shelf energy is greater than 75 ft-lb minimum.

7.

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

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

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.

8.

Containment isolation valve closure times limit potential releases of radioactivity.

A test will be performed of the automatic CIVs.

Each CIV listed in Table 2.1-3 travels from the full open to full closed position in less than or equal to the time listed in Table 2.1-3 after receipt of a containment isolation signal.

NuScale Tier 1 NuScale Power Module Tier 1 2.1-16 Draft Revision 2 22.

i. TheA CNTS containment electrical penetration assemblyies isare rated to withstand fault currents for the time required to clear the fault from its power source.

OR ii. A CNTS containment electrical penetration assembly is rated to withstand the maximum fault current for its circuits without a circuit interrupting device.

i. An analysis will be performed of the CNTS as-built containment electrical penetration assemblyies.

i. A circuit interrupting device coordination analysis exists and concludes that the current carrying capability for eachthe CNTS containment electrical penetration assemblyies listed in Table 2.1-3 is greater than the analyzed fault currents for the time required to clear the fault from its power source.

OR ii. An analysis of the CNTS containment penetration maximum fault current exists and concludes the fault current is less than the current carrying capability of the CNTS containment electrical penetration 23.

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

A preservice design pressure leakage test of the CNV will be performed.

No water leakage is observed at CNV bolted flange connections.

Table 2.1-4: NuScale Power Module Inspections, Tests, Analyses, and Acceptance Criteria (Continued)

No.

Design Commitment Inspections, Tests, Analyses Acceptance Criteria

NuScale Final Safety Analysis Report Interfaces with Certified Design Tier 2 1.8-3 Draft Revision 2 RAI 01-61, RAI 02.04.13-1, RAI 03.04.01-4, RAI 03.04.02-1, RAI 03.04.02-2, RAI 03.04.02-3, RAI 03.05.01.04-1, RAI 03.05.02-2, RAI 03.06.02-6, RAI 03.06.02-15, RAI 03.06.03-11, RAI 03.07.01-2, RAI 03.07.01-3, RAI 03.07.02-6S1, RAI 03.07.02-8, RAI 03.07.02-12, RAI 03.08.04-3S2, RAI 03.08.04-23S1, RAI 03.08.04-23S2, RAI 03.08.05-14S1, RAI 03.09.02-15, RAI 03.09.02-48, RAI 03.09.02-67, RAI 03.09.02-69, RAI 03.09.03-12, RAI 03.09.06-5, RAI 03.09.06-6, RAI 03.09.06-16, RAI 03.09.06-16S1, RAI 03.09.06-27, RAI 03.11-8, RAI 03.11-14, RAI 03.11-14S1, RAI 03.11-18, RAI 03.13-3, RAI 04.02-1S2, RAI 05.02.03-19, RAI 05.02.05-8, RAI 05.04.02.01-13, RAI 05.04.02.01-14, RAI 05.04.02.01-19, RAI 06.02.06-22, RAI 06.02.06-23, RAI 06.04-1, RAI 09.01.01-20, RAI 09.01.02-4, RAI 09.01.05-3, RAI 09.01.05-6, RAI 09.03.02-3, RAI 09.03.02-4, RAI 09.03.02-5, RAI 09.03.02-6, RAI 09.03.02-8, RAI 10.02-1, RAI 10.02-2, RAI 10.02-3, RAI 10.02.03-1, RAI 10.02.03-2, RAI 10.03.06-1, RAI 10.03.06-5, RAI 10.04.06-1, RAI 10.04.06-2, RAI 10.04.06-3, RAI 10.04.10-2, RAI 11.01-2, RAI 12.03-55S1, RAI 13.01.01-1, RAI 13.01.01-1S1, RAI 13.02.02-1, RAI 13.03-4, RAI 13.05.02.01-2, RAI 13.05.02.01-2S1, RAI 13.05.02.01-3, RAI 13.05.02.01-3S1, RAI 13.05.02.01-4, RAI 13.05.02.01-4S1, RAI 14.02-7, RAI 18-46S1, RAI 19-31, RAI 19-31S1, RAI 19-38, RAI 20.01-13 Table 1.8-2: Combined License Information Items Item No.

Description of COL Information Item Section COL Item 1.1-1:

A COL applicant that references the NuScale Power Plant design certification will identify the site-specific plant location.

1.1 COL Item 1.1-2:

A COL applicant that references the NuScale Power Plant design certification will provide the schedules for completion of construction and commercial operation of each power module.

1.1 COL Item 1.4-1:

A COL applicant that references the NuScale Power Plant design certification will identify the prime agents or contractors for the construction and operation of the nuclear power plant.

1.4 COL Item 1.7-1:

A COL applicant that references the NuScale Power Plant design certification will provide site-specific diagrams and legends, as applicable.

1.7 COL Item 1.7-2:

A COL applicant that references the NuScale Power Plant design certification will list additional site-specific piping and instrumentation diagrams and legends as applicable.

1.7 COL Item 1.8-1:

A COL applicant that references the NuScale Power Plant design certification will provide a list of departures from the certified design.

1.8 COL Item 1.9-1:

A COL applicant that references the NuScale Power Plant design certification will review and address the conformance with regulatory criteria in effect six months before the docket date of the COL application for the site-specific portions and operational aspects of the facility design.

1.9 COL Item 1.10-1:

A COL applicant that references the NuScale Power Plant design certification will evaluate the potential hazards resulting from construction activities of the new NuScale facility to the safety-related and risk significant structures, systems, and components of existing operating unit(s) and newly constructed operating unit(s) at the co-located site per 10 CFR 52.79(a)(31).

The evaluation will include identification of management and administrative controls necessary to eliminate or mitigate the consequences of potential hazards and demonstration that the limiting conditions for operation of an operating unit would not be exceeded. This COL item is not applicable for construction activities (build-out of the facility) at an individual NuScale Power Plant with operating NuScale Power Modules.

1.10 COL Item 2.0-1:

A COL applicant that references the NuScale Power Plant design certification will demonstrate that site-specific characteristics are bounded by the design parameters specified in Table 2.0-1.

If site-specific values are not bounded by the values in Table 2.0-1, the COL applicant will demonstrate the acceptability of the site-specific values in the appropriate sections of its combined license application.

2.0 COL Item 2.1-1:

A COL applicant that references the NuScale Power Plant design certification will describe the site geographic and demographic characteristics.

2.1 COL Item 2.2-1:

A COL applicant that references the NuScale Power Plant design certification will describe nearby industrial, transportation, and military facilities. The COL applicant will demonstrate that the design is acceptable for each potential accident, or provide site-specific design alternatives.

2.2 COL Item 2.3-1:

A COL applicant that references the NuScale Power Plant design certification will describe the site-specific meteorological characteristics for Section 2.3.1 through Section 2.3.5, as applicable.

2.3 COL Item 2.4-1:

A COL applicant that references the NuScale Power Plant design certification will investigate and describe the site-specific hydrologic characteristics for Section 2.4.1 through Section 2.4.14, as applicableexcept Section 2.4.8 and Section 2.4.10.

2.4 COL Item 2.5-1:

A COL applicant that references the NuScale Power Plant design certification will describe the site-specific geology, seismology, and geotechnical characteristics for Section 2.5.1 through Section 2.5.5, below.

2.5

NuScale Final Safety Analysis Report Interfaces with Certified Design Tier 2 1.8-10 Draft Revision 2 COL Item 5.3-2:

A COL applicant that references the NuScale Power Plant design certification will develop operating procedures to ensure that transients will not be more severe than those for which the reactor design adequacy had been demonstrated.

5.3 COL Item 5.3-3 A COL applicant that references the NuScale Power Plant design certification will describe their reactor vessel material surveillance program consistent with NUREG 0800, Section 5.3.1.

5.3 COL Item 5.4-1:

A COL applicant that references the NuScale Power Plant design certification will develop and implement a Steam Generator Program for periodic monitoring of the degradation of steam generator components to ensure that steam generator tube integrity is maintained. The Steam Generator Program will be based on the latest revision of Nuclear Energy Institute (NEI) 97-06, Steam Generator Program Guidelines, and applicable Electric Power Research Institute steam generator guidelines at the time of the COL application. The elements of the program will include: assessment of degradation, tube inspection requirements, tube integrity assessment, tube plugging, primary-to-secondary leakage monitoring, shell side integrity and accessibility assessment, steam plant corrosion product deposition assessment, primary and secondary side water chemistry control, foreign material exclusion, loose parts management, contractor oversight, self-assessment, and reporting.

5.4 COL Item 6.2-1:

A COL applicant that references the NuScale Power Plant design certification will develop a containment leakage rate testing program that will identify which option is to be implemented under 10 CFR 50, Appendix J. Option A defines a prescriptive-based testing approach whereas Option B defines a performance-based testing program.

6.2 COL Item 6.2-2:

A COL applicant that references the NuScale Power Plant design certification will verify that the final design of the containment vessel meets the design basis requirement to maintain flange contact pressure at accident temperature, concurrent with peak accident pressure.

6.2 COL Item 6.3-1:

A COL applicant that references the NuScale Power Plant design certification will describe a containment cleanliness program that limits debris within containment. The program should contain the following elements:

Foreign material exclusion controls to limit the introduction of foreign material and debris sources into containment.

Maintenance activity controls, including temporary changes, that confirm the emergency core cooling system function is not reduced by changes to analytical inputs or assumptions or other activities that could introduce debris or potential debris sources into containment.

Controls that limit the introduction of coating materials into containment.

An inspection program to confirm containment vessel cleanliness prior to closing for normal power operation.

6.3 COL Item 6.4-1:

A COL applicant that references the NuScale Power Plant design certification will comply with Regulatory Guide 1.78 Revision 1, Evaluating the Habitability of a Nuclear Power Plant Control Room During a Postulated Hazardous Chemical Release.

6.4 COL Item 6.4-2:

Not used.

6.4 COL Item 6.4-3:

Not used.

6.4 COL Item 6.4-4:

Not used.

6.4 COL Item 6.4-5:

A COL applicant that references the NuScale Power Plant design certification will specify testing and inspection requirements for the control room habitability system, including control room envelope integrity testing. and control room envelope integrity testing as specified in Table 6.4-4.

6.4 COL Item 6.6-1:

A COL applicant that references the NuScale Power Plant design certification will implement an inservice testing program in accordance with 10 CFR 50.55a(f).

6.6 Table 1.8-2: Combined License Information Items (Continued)

Item No.

Description of COL Information Item Section

NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-18 Draft Revision 2 The containment system meets the underlying intent of 10 CFR 50, Appendix J to ensure leak tightness of the CNV and ensure new leak paths do not develop. This is achieved by the local leak rate testing and ISI performed on the CNV, and is facilitated by the CNV design incorporating the following aspects.

The CNV is an ASME Code Class 1 pressure vessel with a relatively low volume and no internal subcompartments.

Preservice test and inspections are similar to RPV requirements, including hydrostatic pressure tests.

RAI 06.02.06-22, RAI 06.02.06-23 There are no penetrations in the CNV design that would only be tested in a 10 CFR 50, Appendix J, Type A integrated leak rate testing.A preservice design pressure leakage test is performed prior to the NPM being placed into service, as described in Section 6.2.6.5.

There are a limited number of known leakage pathways, each with similar seal designs, that are tested in accordance with Type B or Type C requirements of 10 CFR 50, Appendix J.

The ISI Program and planned CNV examinations meet ASME Code NB Class 1 criteria to ensure no new leakage pathways develop.

Disassembly and reassembly procedures and controls for the CNV are similar to the RPV.

Containment vacuum pressure and leak rate into the CNV are constantly monitored during normal operation. The small containment volume and evacuated operating conditions allow for wide-ranging detection capabilities for liquid or vapor leakage.

Automatic engineered safety feature actuation systems initiate on high containment pressure; therefore, containment pressure is maintained below 9.5 psia during operations.

In summary, the CNV is made of corrosion-resistant materials, has a low number of penetrations (26 Type B, 8 Type C), and no penetrations have resilient seals. All penetrations are either ASME Code,Section III NB Class 1 flanged joints capable of 10 CFR 50, Appendix J, Type B testing or NB Class 1 welded nozzles with isolation valves capable of 10 CFR 50, Appendix J, Type C testing. The use of welded nozzles and testable flange seals at the containment penetrations ensure that 10 CFR 50 Appendix J Type B and Type C testing provides an adequate assessment of overall containment leak rate.

Use of typical RPV load combinations for Class 1 vessels is more applicable to the CNV than using the load combinations specified in RG 1.57 because of the increased quality of the fabrication, inspection, and testing required by ASME Code,Section III, Subsection NB for a Class 1 vessel. The intent of RG 1.57 is satisfied by evaluating LOCAs, hydrogen burn, and seismic loads. Evaluations of these loads are to allowable limits, which provide a design that performs its intended function during design basis events.

NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-24 Draft Revision 2 3.8.2.6 Materials, Quality Control, and Special Construction Techniques RAI 03.08.02-1, RAI 03.08.02-2, RAI 03.08.02-7, RAI 03.08.02-9, RAI 03.08.02-10, RAI 03.08.02-11, RAI 03.08.02-12 The CNV materials conform to the requirements of Article NB-2000. The CNV fabrication conforms to the requirements of Article NB-4000 and Article NF-4000. The quality control program involving materials, welding procedures, and nondestructive examination of welds conforms with Subsection NB-2000, NB-4000 and NB-5000 of the ASME Code. The CNV uses no special construction techniques. The materials of construction are shown in Table 6.1-1 and Table 6.1-2.

3.8.2.7 Testing and Inservice Inspection Requirements Nondestructive examination of the CNV pressure-retaining and integrally attached materials meet the requirements of ASME Code,Section III, Article NB-5000 and NF-5000 using examination methods of ASME Code Section V except as modified by NB and NF.

A non-destructive examination plan will be prepared and implemented for the examinations to be performed to satisfy the fabrication and preservice examination requirements of ASME Code,Section III, Article NB-5000 and Article NF-5000, as applicable, and Section XI.

All surfaces to be clad are magnetic particle or liquid penetrant examined in accordance with ASME Code,Section III, Paragraph NB-2545 or NB-2546 prior to cladding.

RAI 03.08.02-1, RAI 03.08.02-2, RAI 03.08.02-7, RAI 03.08.02-9, RAI 03.08.02-10, RAI 03.08.02-11, RAI 03.08.02-12 For those CNV pressure boundary items defined as ASME Code,Section III, Class 1, preservice examinations are in accordance with ASME Code,Section III, Subsubarticle NB-5280 and ASME Section XI, Subarticle IWB-2200 using examination methods of ASME Code,Section V except as modified by NB-5111. These preservice examinations include 100 percent of the pressure boundary welds. Final preservice examinations are performed after hydrostatic testing but prior to code stamping.

In-service inspection of the CNV is performed as described in Section 6.2.1.6.

RAI 06.02.06-22, RAI 06.02.06-23 The design requirement to perform a CNV preservice design pressure leakage test is performed as specified in Section 6.2.6.5. The requirement of this test is to examine for visible leakage from CNV bolted flanged connections prior the NPM being placed into service. Stress conditions as a result of this test are bounded by the hydrostatic conditions and no additional stress check or load combination is required to address this test. Fatigue cycles created by this test are included in the cycles alloted for the hydrostatic test.

NuScale Final Safety Analysis Report Design of Category I Structures Tier 2 3.8-25 Draft Revision 2 RAI 06.02.06-22, RAI 06.02.06-23 Each Type B penetration is local leak-rate tested in accordance with 10 CFR 50, Appendix J prior to performance of the hydrostatic test. For electrical penetration assemblies, this only includes the flange seals. The sheath modules are tested as part of another specification.CNV flanges are tested in accordance with 10 CFR 50, Appendix J, Type B criteria. Each electrical penetration assembly (EPA) is pressure tested periodically in accordance with 10 CFR 50, Appendix J, Type B criteria.

RAI 06.02.06-22, RAI 06.02.06-23 The Type B test pressure is the containment peak accident pressure. The leak rate is established by containment leakage rate program.

Pneumatic testing at a pressure not to exceed 25 percent of design pressure may be applied prior to a hydrostatic test, as a means of locating leaks, in accordance with ASME Code,Section III, Paragraph NB-6112.1(b).

Hydrostatic testing of the CNV is done in accordance with the requirements of NB-6000. The CNV is pressurized using water to a minimum pressure of 1,250 psig and a maximum pressure of 1,325 psig, the pressure being measured at the bottom of the CNV. The test is performed with the CNV at a minimum temperature of 70 degrees F and a maximum temperature of 140 degrees F. Following a minimum time of 10 minutes at the hydrostatic test pressure, pressure is reduced to design pressure and held for at least four hours before examining for leaks.

If the CNV is hydrostatically tested with the RPV installed, both primary and secondary sides of the RPV are vented to the CNV to preclude a differential pressure external to the RPV greater than considered for design of the RPV.

The hydrostatic test procedure includes measures for sampling the test fluid (water) which contacts the CNV during hydrostatic testing.

Drain water is tested following hydrostatic testing for compliance with the purity requirements. The hydrostatic test procedure includes corrective actions to be taken (e.g. circulating flushes or fill and drains) in the event the exit fluid exceeds purity requirements.

Immediately following hydrostatic testing, the CNV is drained and dried by circulating air until the exit air dew-point temperature is less than 50 degrees F. The circulating air is oil free and does not to contain combustion products from the heating source. The temperature of the dry heated air is controlled to preclude damage to the SGs due to excessive differential temperature.

The shop hydrostatic tests of the CNV are witnessed by an authorized nuclear inspector and a NuScale inspector.

No leakage indications at the examination pressure are acceptable.

NuScale Final Safety Analysis Report Containment Systems Tier 2 6.2-52 Draft Revision 2 including emergency planning. This is described in more detail by Reference 6.2-3, Section 2.7.

6.2.6 Containment Leakage Testing Containment leakage rate testing is designed to verify the leak tight integrity of the reactor containment. The CIVs on CNV piping penetrations, and the passive containment isolation barriers are designed to permit the periodic leakage testing described in GDCs 53 and 54 to ensure leakage through the CNTS and components does not exceed the allowable leakage rate specified in Technical Specifications. Compliance with GDCs 52, 53 and 54 is further described in Section 3.1. The NuScale design supports an exemption from the integrated leak rate testing specified in the GDC 52 criterion. Further details are provided by Reference 6.2-6.

The preoperational and periodic containment leakage testing requirements and acceptance criteria that demonstrate leak-tight integrity of the CNTS and associated components are prescribed in 10 CFR 50, Appendix J and implemented through the reactor containment leakage rate testing program described in Section 5 of the Technical Specifications.

The design of containment penetrations support performance of local leak rate tests (Type B and Type C tests) in accordance with the guidance provided in ANSI/ANS 56.8, Regulatory Guide 1.163, and NEI 94-01. The NuScale system design, in conformance with 10 CFR 50.54(o), accommodates the 10 CFR 50, Appendix J, test method frequencies of Option A or Option B.

COL Item 6.2-1:

A COL applicant that references the NuScale Power Plant design certification will develop a containment leakage rate testing program that will identify which option is to be implemented under 10 CFR 50, Appendix J. Option A defines a prescriptive-based testing approach whereas Option B defines a performance-based testing program.

RAI 06.02.06-22, RAI 06.02.06-23 COL Item 6.2-2:

A COL applicant that references the NuScale Power Plant design certification will verify that the final design of the containment vessel meets the design basis requirement to maintain flange contact pressure at accident temperature, concurrent with peak accident pressure.

RAI 06.02.06-22, RAI 06.02.06-23 A containment flange bolting calculation demonstrates each containment flange design at design bolting preload, maintains flange contact pressure at accident temperature, concurrent with peak accident pressure. To verify the leak tightness of the reactor containment, a preservice design pressure leakage test and Type B, and Type C tests are performed prior to initial operations and Type B and Type C tests are periodically performed thereafter to assure that leakage rates through the containment and the systems or components that penetrate containment do not exceed the maximum allowable leak rate. The CNV preservice design pressure leakage test is performed as

NuScale Final Safety Analysis Report Containment Systems Tier 2 6.2-53 Draft Revision 2 specified in Section 6.2.6.5. Flange preload verifications are performed to ensure that flange bolting is preloaded to design requirements.

The specified maximum allowable containment leak rate, La, is 0.20 weight percent of the containment air mass per day at the calculated peak accident pressure, Pa, identified in Section 6.2.1. Containment leak rate testing is designed to verify that leakage from containment remains within the prescribed Technical Specification limits.

The reactor containment, containment penetrations, and isolation barriers are designed to permit periodic leakage rate testing in accordance with GDC 53 and GDC 54 independent of other NuScale Power Modules.

6.2.6.1 Containment Integrated Leakage Rate Test The NuScale CNV design is different from traditional containments and exempt from GDC 52 criterion because integrated leakage rate testing as described of 10 CFR 50 Appendix J, Type A tests, are not required to meet the purpose of the rule. Specifically, the CNV is a high pressure vessel.

an ASME Class MC component constructed to ASME Class 1 vessel rules.

constructed of all stainless steel clad or stainless materials.

designed with penetrations that are either ASME Class 1 flanged joints capable of Type B testing or ASME Class 1 welded nozzles with isolation valves capable of Type C testing.

inaccessible (interior) to personnel during startup, shutdown and normal operation.

under a vacuum and partially immersed in borated water during normal operation.

constantly monitored during normal operation for containment vacuum and leakage into containment.

disassembled by separating the upper and lower CNV shells during outages for refueling, maintenance and inspection.

GDC 52 requires that containments are designed so that periodic integrated leakage rate testing can be conducted at containment design pressure. The purpose of GDC 52 is to provide design capability for testing to verify leakage tightness to ensure continued leakage integrity of the CNTS. The CNTS meets the purpose of the rule due to the unique features of the NuScale Power containment design.

Manufacturing and preservice test and inspections are similar to RPV requirements.

All known leakage pathways will be Type B or Type C tested.

Comprehensive ISI will meet ASME Class 1 criteria to ensure no new leakage pathways develop.

RAI 06.02.06-22, RAI 06.02.06-23

NuScale Final Safety Analysis Report Containment Systems Tier 2 6.2-54 Draft Revision 2 The CNV is an ASME Subsection NE, Class MC containment, and is designed, fabricated, and stamped as an ASME Subsection NB, Class 1 pressure vessel, except that overpressure protection is in accordance with NE 7000, see Subsection 3.8.2. The CNV is made of corrosion resistant materials, has a low number of penetrations, and no penetrations have resilient seals. The use of all welded nozzles and testable flange seals at every containment penetration ensure that Type B and C testing provides an adequate assessment of containment leak rate. A containment flange bolting calculation provides assurance that containment flanges maintain contact pressure at accident temperature concurrent with peak accident pressure.

The NuScale design has fewer and smaller potential leak pathways than traditional, large pressurized water reactors, which provides a meaningful safety advantage. The small size of the containment allows for factory fabrication, which facilitates increased quality and testing control than field construction.

Pressure retaining and integrally attached materials meet the requirements of ASME Subsections NB-5000 and NF-5000 using the examination methods of ASME Section V.

All surfaces to be clad will be magnetic particle or liquid penetrant examined in accordance with ASME Subsections NB-2545 or NB-2546, respectively.

Preservice examinations for ASME Class 1 pressure boundary items will be performed in accordance with ASME Subsection NB-5280 and ASME Section XI, Subsection IWB-2200 using the examination methods of ASME Section V, except as modified by ASME Subsection NB-5111. These preservice examinations include 100 percent of the pressure boundary welds.

Final preservice examinations will be performed after hydrostatic testing but prior to code stamping.

RAI 06.02.06-22, RAI 06.02.06-23 The CNV is hydrostatically tested in accordance with ASME Subsection NB-6000. The test is conducted with the RPV installed and vented. The water-filled CNV is pressurized to a minimum of 25 percent over design pressure for at least ten minutes. Pressure is then reduced to design pressure and held for at least four hours prior to examining for leaks. The acceptance criterion is no leakage indications at the examination pressure (design pressure). Each CNV undergoes a preservice design pressure leakage test which tests all CNV bolted flange connections under design preload at design pressure, as described in Section 6.2.6.5. The acceptance criterion is no observed leakage from CNV bolted flange connections at examination pressure.

ASME Class MC, Section IWE, only requires visual examination for SSC subject to normal degradation and aging. Surface areas that are subject to accelerated degradation and aging require an ultrasonic thickness exam. However, based on the high pressure and safety functions of the CNV, the Inservice Inspection Program requires the CNV to meet ASME Class 1 requirements, similar to the RPV. The CNV design allows for visual inspection of the entire inner and outer surfaces; therefore, developing a leak through the metal pressure boundary is implausible.

NuScale Final Safety Analysis Report Containment Systems Tier 2 6.2-59 Draft Revision 2 6.2.6.5 Special Testing Requirements RAI 06.02.06-22, RAI 06.02.06-23 6.2.6.5.1 Testing Following Major Component Modification or Replacement Major modifications or replacement of components that are part of the containment boundary performed after preoperational leakage rate testing is followed by a Type B or Type C test as applicable for the area affected by the modification. The measured leakage from the test is included in the summary report.

RAI 06.02.06-22, RAI 06.02.06-23 6.2.6.5.2 Preservice Design Pressure Leakage Test RAI 06.02.06-22, RAI 06.02.06-23 Each CNV undergoes a preservice design pressure leakage test which tests CNV bolted flange connections under design preload at CNV design pressure. The preservice design pressure leakage test is performed with the containment vessel filled with water similar to a hydrostatic test. The preservice design pressure leakage test of the initial as-built containment vessel is performed on an assembled containment vessel using the as-designed flange covers, installed with the design bolting materials, design bolting preloads and design seals installed. Covers with electrical and instrumentation penetrations may be substituted with blank covers having the same bolting and sealing design as the inservice covers. The test configuration may utilize blanked off pipe ends in place of the containment isolation valves. The upper and lower halves of subsequent containment vessels may be tested separately. At design pressure, and a test temperature of a minimum of 70 degrees F and a maximum of 140 degrees F, a leakage check of the CNV bolted flange connections is performed. The acceptance criterion is no observed leakage from seals at examination pressure.

RAI 06.02.06-22, RAI 06.02.06-23 Each ECCS trip valve and reset valve contains a body-to-bonnet joint that is also subject to Type B test requirements. The body-to-bonnet seal is designed for RCS design pressure. This seal is tested to meet both Type B and RCPB criteria every refueling outage. These body-to-bonnet seals are not considered to be a flanged connection and are not included in the containment flange bolting calculation or preservice design pressure leakage test.

6.2.7 Fracture Prevention of Containment Vessel The NuScale CNTS encloses the RPV providing a CNV pressure boundary and provides an essentially leak-tight final barrier against the release of radioactive fission products resulting from postulated accidents. Design of the steel containment is addressed in Section 3.8.2.

NuScale Final Safety Analysis Report Certified Design Material and Inspections, Tests, Analyses, and Acceptance Criteria Tier 2 14.3-14 Draft Revision 2 RAI 06.02.06-22, RAI 06.02.06-23, RAI 08.01-1S1, RAI 08.01-2, RAI 10.02-3, RAI 10.02.03-1, RAI 10.02.03-2, RAI 14.03.03-3S1, RAI 14.03.03-4S1, RAI 14.03.03-6, RAI 14.03.03-6S1, RAI 14.03.03-7, RAI 14.03.03-7S1, RAI 14.03.03-8, RAI 14.03.03-9, RAI 14.03.03-9S1 Table 14.3-1: Module-Specific Structures, Systems, and Components Based Design Features and Inspections, Tests, Analyses, and Acceptance Criteria Cross Reference(1)

ITAAC No.

System Discussion DBA Internal/External Hazard Radiological PRA & Severe Accident FP 02.01.01 NPM As required by ASME Code Section III NCA-1210, each ASME Code Class 1, 2 and 3 component (including piping systems) of a nuclear power plant requires a Design Report in accordance with NCA-3550. NCA-3551.1 requires that the drawings used for construction be in agreement with the Design Report before it is certified and be identified and described in the Design Report. It is the responsibility of the N Certificate Holder to furnish a Design Report for each component and support, except as provided in NCA-3551.2 and NCA-3551.3. NCA-3551.1 also requires that the Design Report be certified by a registered professional engineer when it is for Class 1 components and supports, Class CS core support structures, Class MC vessels and supports, Class 2 vessels designed to NC-3200 (NC-3131.1), or Class 2 or Class 3 components designed to Service Loadings greater than Design Loadings. A Class 2 Design Report shall be prepared for Class 1 piping NPS 1 or smaller that is designed in accordance with the rules of Subsection NC. NCA-3554 requires that any modification of any document used for construction, from the corresponding document used for design analysis, shall be reconciled with the Design Report.

An ITAAC inspection is performed of the NuScale Power Module ASME Code Class 1, 2 and 3 as-built piping system Design Report to verify that the requirements of ASME Code Section III are met.

X

NuScale Final Safety Analysis Report Certified Design Material and Inspections, Tests, Analyses, and Acceptance Criteria Tier 2 14.3-17 Draft Revision 2 02.01.05 NPM Section 3.6.3, Leak-Before-Break Evaluation Procedures, describes the application of the mechanistic pipe break criteria, commonly referred to as leak-before-break (LBB), to the evaluation of pipe ruptures. The LBB analysis eliminates the need to consider the dynamic effects of postulated pipe breaks for high-energy piping that qualify for LBB.

An analysis, which includes material properties of piping and welds, stress analyses, leakage detection capability, and degradation mechanisms, confirms that the as-designed LBB analysis is bounding for the ASME Code Class 2 as-built piping listed in Tier 1 Table 2.1-1 and interconnected equipment nozzles.

A summary of the results of the plant specific LBB analysis, including material properties of piping and welds, stress analyses, leakage detection capability, and degradation mechanisms is provided in the as-built LBB analysis report.

X 02.01.06 NPM Section 5.3.1.5, Fracture Toughness, discusses the fracture toughness properties of the reactor pressure vessel (RPV) beltline material and the Material Surveillance Program. A Charpy V-Notch test of the RPV beltline material specimen is performed by the vendor to ensure that the initial RPV beltline Charpy upper-shelf energy is no less than 75 ft-lb minimum.

X 02.01.07 NPM Section 6.2.6, Containment Leakage Testing, provides a discussion of the leakage testing requirements of the containment vessel (CNV), which serves as an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment. As discussed in Section 6.2.6, the NuScale CNV is exempted from the integrated leak rate testing specified in the General Design Criterion (GDC) 52.

In accordance with Table 14.2-43, a preoperational test demonstrates that the leakage rate for local leak rate tests (Type B and Type C) for pressure containing or leakage-limiting boundaries and containment isolation valves (CIVs) meet the leakage acceptance criterion of 10 CFR Part 50, Appendix J.

X Table 14.3-1: Module-Specific Structures, Systems, and Components Based Design Features and Inspections, Tests, Analyses, and Acceptance Criteria Cross Reference(1) (Continued)

ITAAC No.

System Discussion DBA Internal/External Hazard Radiological PRA & Severe Accident FP

NuScale Final Safety Analysis Report Certified Design Material and Inspections, Tests, Analyses, and Acceptance Criteria Tier 2 14.3-25 Draft Revision 2 02.01.22 NPM Section 8.3.1.2.2, Circuit Protection and Coordination, discusses instantaneous and thermal overload fault protection to limit the loss of equipment due to postulated fault conditions.

A circuit interrupting device coordination analysis confirms that the as-built containment electrical penetration assemblies listed in Tier 1 Table 2.1-3 can withstand fault currents for the time required to clear the fault from its power source.

The CNTS electrical penetrations listed in Tier 2 Table 2.1-3 may be one of two types, one with or without a circuit interrupting device.

An ITAAC confirms that each type of penetration is evaluated to confirm it can withstand its maximum fault current.

A circuit interrupting device coordination analysis confirms and concludes in a report that the as-built containment electrical penetration assembly listed in Tier 1 Table 2.1-3 that has a circuit interrupting device can withstand fault currents for the time required to clear the fault from its power source.

8.3.1.2.5 Containment Electrical Penetration Assemblies discusses electrical penetration assemblies that are not equipped with protection devices whose maximum fault current in these circuits would not damage the electrical penetration assembly if that fault current was available indefinitely. An analysis of a CNTS as-built containment penetration without a circuit interrupting device confirms and concludes in a report that the maximum fault current is less than the current carrying capability of the CNTS containment electrical penetration.

X 02.01.23 NPM Section 6.2.6.5.2 Preservice Design Pressure Leakage Test provides the test requirements for a preservice design pressure leakage test of the CNV. The test verifies no observed leakage at the CNV bolted flange connections under design pressure.

The test may be performed any time after manufacture of the containment vessel, prior to the NPM being placed into service.

Table 14.3-1: Module-Specific Structures, Systems, and Components Based Design Features and Inspections, Tests, Analyses, and Acceptance Criteria Cross Reference(1) (Continued)

ITAAC No.

System Discussion DBA Internal/External Hazard Radiological PRA & Severe Accident FP

Exemptions 10 CFR 52, App. A, GDC 52 Containment Leakage Rate Testing Part 7 7-3 Draft Revision 2 As a result of the approval and adoption of the proposed Appendix J exemption in the NuScale design certification rule, plants referencing the NuScale design shall be exempt from the requirements of 10 CFR 50 Appendix J Type A tests.

7.2 Justification for Exemption The underlying purpose of GDC 52 is to ensure that the containment is designed to enable testing to provide assurance that the leakage integrity of containment is maintained during its service life and to provide assurance of the performance of the overall containment system as a barrier to fission product releases. 10 CFR 50, Appendix J identifies containment leakage rate inspection and testing requirements for licensees, including periodic ILRT (Type A tests) as described in GDC 52, as well as local leak rate tests (LLRTs) for equipment penetrations and valves that represent potential containment leakage pathways (Type B and C tests). Appendix J identifies the purpose of containment ILRT as:

to assure that leakage through the primary reactor containment and systems and components penetrating primary containment shall not exceed allowable leakage rate values as specified in the technical specifications or associated bases The NuScale Power Plant CNV design allows testing and inspection, other than as anticipated by GDC 52, which meets the underlying purpose of the rule to assure CNV leakage integrity.

The alternate NuScale CNV design, testing, and inspection requirements provide equivalent CNV leakage integrity assurance, and thus meets the underlying purpose of the rule.

7.2.1 Technical Basis RAI 06.02.06-22, RAI 06.02.06-23 Underlying purpose of the rule. The NuScale containment provides design capability for testing and inspection which assures that the leakage integrity of containment is maintained and that CNV leakage does not exceed allowable leakage rate values, thereby meeting the underlying purpose of the rule. NuScale's containment design allows for comprehensive inspection and examination to provide assurance that no unknown leakage pathways exist. NuScale's containment design ensures that containment flanges maintain contact pressure at accident temperature conditions, concurrent with peak accident pressure. Because no unknown leakage pathways exist, and because all penetration and CIV designs support accurate LLRT results, and because containment flange bolting preload verifications ensure the containment flanges are installed per design, quantification of overall containment leakage can be accomplished using Type B and C tests.

As described in FSAR Section 6.2, the NuScale Power Plant CNV is an American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code Class MC component (inclusive of all access and inspection openings, penetrations for emergency core cooling system trip/reset valves, and openings for electrical penetration assemblies). As permitted by ASME NCA-2134(c), the complete CNV is constructed and stamped as an ASME Class 1 vessel in accordance with ASME Boiler and Pressure Vessel Code,Section III, Subsection NB.

All penetrations that are potential leakage pathways are either ASME Class 1 flanged joints capable of Type B testing or ASME Class 1 welded nozzles with isolation valves capable of Type C testing. Because the potential vessel leakage pathways are testable containment

Exemptions 10 CFR 52, App. A, GDC 52 Containment Leakage Rate Testing Part 7 7-4 Draft Revision 2 penetrations, total CNV leakage can be quantified via 10 CFR 50, Appendix J, Type B and C tests, thus assuring that CNV leakage does not exceed allowable leakage rate values.

Comprehensive inservice inspection ensures that no new leakage pathways develop over the life of the containment system.

NuScale containment leakage integrity assurance is described in NuScale's Technical Report TR-1116-51962. The primary elements discussed in TR-1116-51962 include:

factory inspection and testing, including hydrostatic testing with zero leakage, to assure initial containment leakage integrity per ASME Section III, Class 1 pressure vessel requirements (i.e., assures that no unknown leakage pathways exist)

RAI 06.02.06-22, RAI 06.02.06-23 Preservice design pressure leakage testing that loads CNV bolted flange connections to containment design pressure and confirms no visible leakage under these conditions.

preservice and periodic Type B and C testing of penetrations to assure that overall containment leakage does not exceed allowable leakage rate values (i.e., quantifies overall containment leak rates)

RAI 06.02.06-22, RAI 06.02.06-23 Containment flange bolting preloading verifications that confirm the flange bolting is preloaded to the design value that maintains flange contact pressure at accident temperature conditions, concurrent with peak accident pressure.

ASME Section III, Class 1, design, construction, inspection, examination, and testing, and ASME Section XI (inservice testing and inspection, repair and replacement, scheduled examinations, non-destructive examination (NDE) methods, and flaw size characterization, including post-maintenance inspection, examination, and testing for CNV repairs or modifications) to assure continued leakage integrity (i.e., assures that no unknown leak pathways develop over time)

Type B and C testing, inspections, and administrative controls (e.g., configuration management and procedural requirements for system restoration) to assure leakage integrity associated with activity-based failure mechanisms (i.e., assures that CNV penetrations and CIVs remain within allowable leakage rate values after system and component modifications or maintenance)

The alternate NuScale CNV design, testing, examination, and inspection requirements provide assurance that the leakage integrity of containment is maintained during its service life to support performance of the overall containment system as a barrier to fission product releases, and thereby meet the underlying purpose of the rule.

Circumstances not considered when the regulation was adopted. Other material circumstances are present which were not considered when the regulation was adopted.

The requirements of GDC 52 and the test criteria described in Appendix J were established for containment designs different from the NuScale CNV design. A typical containment (i.e.,

typical of the current operating fleet of nuclear power plants) is a large, permanent, welded steel plate structure, with multiple levels, sub-compartments, and internal structures. The steel containment structures create potential leak pathways, and CNV inspections are not able to access all relevant portions of the typical containment. Unknown leakage pathways may develop over time via degradation or damage of the steel liner and could go undetected due to limited inspection access availability. For this type of containment

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

Abstract This technical report describes the NuScale Power, LLC (NuScale) Containment Leakage Integrity Program (CLIP). This program provides assurance that leakage integrity of containment is maintained and that containment leakage does not exceed allowable leakage rate values. The CLIP is a consolidation of programs described in the NuScale Design Certification Application (DCA). All CLIP elements are implemented under other programs as described in this report and the NuScale DCA. The requirements of 10 CFR 50, Appendix A, General Design Criterion 52 (GDC 52) state that containments shall be designed so that periodic integrated leakage rate testing can be conducted at containment design pressure. The requirements of 10 CFR 50, Appendix J, Type A tests, include test specifications directly related to GDC 52 design requirements. The CLIP integrates:

containment vessel flange design that remains sealed at design pressurepreservice inspection at the manufacturing facility preservice leak test at design pressure performed for all containment vesselsstructural integrity testing at the manufacturing facility initial (first-of-a-kind) containment vessel preservice leak test at design pressure performed with the vessel fully assembled with all flanges in placeleakage testing at the manufacturing facility preservice 10 CFR 50, Appendix J, Type B testing preservice 10 CFR 50, Appendix J, Type C testing post-installation and repair inspection and testing inservice inspection and examination periodic 10 CFR 50, Appendix J, Type B testing periodic 10 CFR 50, Appendix J, Type C testing This report provides relevant details of the NuScale containment vessel and containment systems designs, which support the CLIP in assuring containment leakage integrity. The NuScale CLIP provides leakage integrity assurance equivalent to the containment leakage testing requirements of 10 CFR 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors. This report provides supplemental information designed to inform the NRCs evaluation of NuScale Final Safety Analysis Report Section 6.2.6 and DCA Part 7, Section 7, GDC 52 exemption request.

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

Executive Summary This technical report (TR) describes NuScales Containment Leakage Integrity Program (CLIP).

The CLIP, supported by the NuScale containment vessel (CNV) and containment system (CNTS) design, provides leakage integrity assurance for the NuScale containment. As discussed in the NuScale Design Certification Application (DCA), Part 7, Exemption Requests, NuScale is requesting an exemption from the requirements of 10 CFR 50, Appendix A, General Design Criterion (GDC) 52 and 10 CFR 50, Appendix J, which specify the design for and performance of preoperational and periodic integrated leak rate testing at containment design pressure.

The CLIP, supported by the design and analysis of the NuScale CNV and CNTS, provides leakage integrity assurance for the NuScale containment. The CLIP is a consolidation of programs described in the NuScale DCA. All CLIP elements are implemented under other programs as described in this report and the NuScale DCA. Each element of NuScales CLIP is consistent with a corresponding element of an approved program for reactor pressure vessels (RPVs) or large light water reactor (LLWR) containments. The primary CLIP elements that provide leakage integrity assurance include:

CNV flanges are designed to remain sealed at design pressure factory inspection and testing, including preservice leakhydrostatic testing with at design pressure zero visible leakage, to ensure initial containment leakage integrity in accordance with an ITAACper ASME Section III, Class 1 pressure vessel requirements (i.e., ensures that no unknown leakage pathways exist) preservice and periodic Type B and C testing to ensure that overall containment leakage does not exceed allowable leakage rate values (i.e., quantifies overall containment leak rates)

ASME Section III, Class 1, design, construction, inspection, examination, and testing, and ASME Section OM and XI [(inservice testing (IST) and inservice inspection (ISI), repair and replacement, scheduled examinations, non-destructive examination methods, and flaw size characterization, including post-maintenance inspection, examination, and testing for CNV repairs or modifications)] to ensure continued leakage integrity (i.e., ensures that no unknown leak pathways develop over time)

Type B and C testing, inspections, and administrative controls (e.g., configuration management and procedural requirements for system restoration) to ensure leakage integrity associated with activity-based failure mechanisms [i.e., ensures that CNV flanges and containment isolation valves (CIVs) remain within allowable leakage rate values after system and component modifications or maintenance]

While the CLIP described in this report does not conform to GDC 52 and Type A testing requirements, the advanced NuScale design and CLIP provide more complete leakage integrity assurance than was considered when the subject regulations were adopted. This report provides a detailed overview of the key aspects of the testing, inspection, and design that ensures NuScales containment leakage integrity is maintained, including:

the overall containment leakage rate testing program, including the scope of the Type B and C testing to ensure adequate margin against design-basis leak rates Type B testing adequacy is assured by:

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

CNV flanges are designed to remain sealed at design pressure preservice design pressure leakage test of the CNV with CNV bolted flanges in place utilizing as-designed flange covers installed with the design bolting materials, design bolting assembly preloads, and design seals installed to demonstrate no leakage at design pressure. The test is performed at design pressure and a minimum temperature of 70 degrees F and a maximum temperature of 140 degrees F the upper and lower halves of the CNV are assembled for the first module of the initial NuScale plant after successful testing, the upper and lower halves of all other CNVs may be tested separately covers with electrical and instrumentation penetrations may be substituted with blank covers having the same sealing design flange assembly utilizes positive verification to ensure proper flange loading from each stud The test configuration may utilize blanked off pipe ends in place of the containment isolation valves The acceptance criterion is no observed leakage from seals at examination pressure The ECCS trip valve and reset valve body-to-bonnet joint seals are not considered to be a flanged connection and are not included in the containment flange bolting calculation or preservice design pressure leakage test the CNTS design as it applies to the containment function the ISI program as it applies to the CNV the IST program as it applies to CIVs materials selection and aging degradation assessment As described in this report, the NuScale containment design and CLIP ensure that leakage integrity of containment is maintained and that containment leakage does not exceed allowable leakage rate values. This report provides supplemental information designed to inform the NRCs evaluation of NuScale Final Safety Analysis Report (FSAR) Section 6.2.6 and DCA Part 7, Section 7, GDC 52 exemption request.

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

1.0 Introduction 1.1 Purpose The purpose of this technical report is to describe NuScales CLIP as well as the CNV and CNTS design elements that ensure leakage integrity. This report evaluates the NuScale plant design and CLIP against the requirements in 10 CFR 50, Appendix J (Reference 7.1.3) as incorporated in Design-Specific Review Standard (DSRS), Section 6.2.6 (Reference 7.1.6). This evaluation includes an assessment of the capability of the NuScale containment design to meet specific testing requirements in 10 CFR 50, Appendix J. This report identifies Type A requirements that will not be applied because the fundamental functionality is achieved differently. This report describes NuScales approach to Type B and Type C testing through an evaluation of the containment design.

This report provides supplemental information designed to inform the NRCs evaluation of NuScale FSAR Section 6.2.6 and DCA Part 7, Section 7, GDC 52 exemption request.

As shown in the table below, each element of NuScales CLIP is consistent with a corresponding element of an approved program for reactor pressure vessels (RPVs) or LLWR containments, which have been incorporated within the NuScale DCA. This report provides a consolidated description of inspection, testing, and examination elements from several programs described in the NuScale DCA related to containment leakage integrity. This report does not describe any elements that are not described in the NuScale DCA.

Table 1-1 Containment leakage integrity program elements CLIP Element NuScale DCA Requirement CNV flange design FSAR COL Item 6.2-2 Preservice inspection (TR Section 4)

ASME III (FSAR 6.2)

Fabrication structural integrity testing (TR Section 4)

ASME III (FSAR 6.2)

Preservice leakage testing (TR Section 4)

FSAR 6.2.6, DCA Tier 1, (ITAAC)ASME III (FSAR 6.2)

Preservice Type B and C local leakage rate test (LLRT)

(TR Section 4)

Technical Specifications (TS) (DCA Part 4, Section 5.5.9)

Preservice Type B and C LLRT (TR Section 4)

Initial Test Program (FSAR Table 14.2-43)

Post-installation/repair inspection & testing (TR Section 5)

ASME III / XI (FSAR 6.2)

Post-installation/repair inspection & testing (TR Section 5)

TS (DCA Part 4, Section 5.5.9)

Inservice inspection and examination (TR Section 5)

ASME XI (FSAR 6.2)

Periodic Type B and C LLRT (TR Section 5)

TS (DCA Part 4, Section 5.5.9) 1.2 Scope This report describes the CLIP for the NuScale design and evaluates the NuScale CLIP against 10 CFR 50, Appendix J. This report describes the overall containment leakage rate testing (CLRT) program, including the scope and frequency of Type B and C testing of CNV penetrations.

the CNTS design as it applies to CNV design and the containment function.

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materials selection and aging degradation as it applies to the containment pressure boundary the ISI program as it applies to the CNV the IST program as it applies to containment isolation valves (CIVs)

Type A integrated leak rate testing impediments

1.3 Background

Pursuant to 10 CFR 52.7, NuScale is requesting an exemption from GDC 52. 10 CFR 50, Appendix J specifies Type A testing directly related to GDC 52. While Appendix J is not applicable to a design certification applicant, NuScale is also planning to request that the approval of the GDC 52 exemption within the NuScale Power Plant design certification include exemption from the requirements of 10 CFR 50, Appendix J Type A testing for plants referencing the NuScale design certification.

This technical report describes the NuScale containment testing, inspection, and design criteria that ensure leakage integrity of containment is maintained and that containment leakage does not exceed allowable leakage rate values.

1.4 Containment Leakage Integrity Assurance The NuScale CLIP provides containment leakage integrity by demonstrating that the NuScale containment design can use LLRT to adequately ensure containment leakage integrity CNV flanges are design to remain sealed at design pressure preservice design pressure leakage test of the CNV with CNV bolted flanges in place utilizing as-designed flange covers installed with the design bolting materials, design bolting assembly preloads, and design seals installed to demonstrate no leakage at design pressure the upper and lower halves of the CNV are assembled for the first module of the initial NuScale plant after successful testing, the upper and lower halves of all other CNVs may be tested separately covers with electrical and instrumentation penetrations may be substituted with blank covers having the same sealing design flange assembly utilizes positive verification to ensure proper flange loading from each stud.

ensuring no unknown leakage pathways exist.

quantifying overall containment leak rates by LLRTs that provide accurate results for every potential leak path.

ensuring no unknown leak paths develop over time due to degradation.

ensuring no unknown leak paths develop due to activity-based failure mechanisms.

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© Copyright 2016 2018 by NuScale Power, LLC 10 2.0 Containment Leakage Integrity Assurance Overview NuScale CLIP testing, inspection, and examination, supported by the design and analysis of the NuScale CNV and CNTS, ensure leakage integrity is maintained for the NuScale containment. The CLRT, in combination with other CLIP elements, verifies the leakage integrity of the reactor containment by testing that the actual containment leakage rates do not exceed the values assumed in the applicable safety analysis calculations for design basis events. The preoperational and periodic CLRT requirements and acceptance criteria that demonstrate leakage integrity of the CNTS and associated components are performedprescribed in accordance with 10 CFR 50, Appendix J) and implemented through the licensees CLRT program described in Section 5.5.9 of the technical specifications, Part 4 of the NuScale DCA. The maximum allowable containment leakage rate is referred to as La, and this leakage rate is measured at peak containment accident pressure (Pa) (these terms are defined in 10 CFR 50, Appendix J). The containment penetrations and containment isolation barriers are designed to permit the periodic leakage testing described in GDC 53 and 54 to verify leakage through the containment penetrations does not exceed the allowable leakage rate.

The design of the containment penetrations support performance of Type B and Type C testing in accordance with the guidance provided in Regulatory Guide 1.163 (Reference 7.1.4), ANSI/ANS 56.8 (Reference 7.1.10) and NEI 94-01 (Reference 7.1.12). The NuScale CNTS design accommodates both test method frequencies permitted by 10 CFR 50, Appendix J; Option A, Prescriptive Requirements and Option B, Performance-Based Requirements. Only Option A will be available to initial NuScale licensed plants, as there will not be sufficient performance history to use Option B. Initial COL applicants that reference the NuScale Power Plant design certification will develop a CLRT program which will identify Option A to be implemented under 10 CFR 50, Appendix J.

The NuScale containment is designed for all flanged joints to remain sealed at design pressure. The NuScale containment is initially inspected and tested at the factory, including ASME hydrostatic testing with an acceptance criterion of zero leakage, to verify that no unknown leak pathways exist. Additionally, a CNV preservice design pressure leakage test is performed that loads CNV bolted flange connections to containment design pressure and confirms no observed leakage under these conditions.Preservice inspection and testing at the plant site verifies factory test results (i.e., any potential shipping or assembly degradation mechanisms that could impact containment leakage are verifiable by preservice inspection and testing which include Type B and C testing for penetrations and CIVs). Because all potential leakage pathways are known and testable, preservice and periodic Type B and C testing quantify the overall containment leakage rate to verify that maximum allowable leakage is not exceeded (i.e., the design and configuration of all potential leak pathways, including CNV flanges and CIVs, provide for LLRT results to meet containment integrated leakage rate acceptance criteria). Periodic inspection and testing verifies that no unknown leakage pathways develop over time (i.e., any potential through-wall degradation will be precluded as a credible mechanism for containment leakage). Post-maintenance inspection and testing, including Type B and C testing and administrative controls, verify that no unknown leakage pathways develop due to activity-based failure mechanisms during maintenance or modifications.

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© Copyright 2016 2018 by NuScale Power, LLC 11 2.1 NuScale Containment Vessel Structure The NuScale CNV design ensures leakage integrity through design, inspection and testing other than as required by GDC 52 and Appendix J. NEI 94-01 (Reference 7.1.12) describes the purpose of 10 CFR 50, Appendix J for traditional large containment structures:

The purpose of Type A testing is to verify the leakage integrity of the containment structure. The primary performance objective of the Type A test is not to quantify an overall containment system leakage rate. The Type A testing methodology as described in ANSI/ANS-56.8-2002 serves to ensure continued leakage integrity of the containment structure. Type B and Type C testing ensures that individual leakage rates support the leakage tightness of primary containment by minimizing potential leakage paths.

Continued leakage integrity of the NuScale CNV structure is ensured by precluding through-wall degradation as a credible leakage mechanism. The NuScale CNV is a welded metal vessel design, in contrast to existing pressurized water reactors (PWRs) that incorporate large containment building structures. The containment is designed for all flanged joints to remain sealed at design pressure. Manufacturing acceptance tests and inspections are similar to RPV tests and inspections, and are performed in a factory environment. Comprehensive ISI applying ASME Code Class 1 criteria also ensures no new leakage paths develop over the life of the plant due to degradation. All surface areas and welds are accessible for inspection. Additionally, a separate preservice design pressure leakage test is required for all containment vessels with CNV bolted flange connections in place to demonstrate no observed leakage utilizing as-designed flange covers installed with the design bolting materials, design bolting assembly preloads, and design seals installed. This leakage test is required by an ITAAC. The first CNV of the initial plant shall be tested with the upper and lower halves of the containment vessel assembled. Penetration pathways are tested to Type B or C criteria at peak containment accident pressure. These features ensure that continued leakage integrity of the CNTS is maintained without the need for Type A testing.

The NuScale CNV design is different from traditional containments in several fundamental aspects. These design differences impact conformance with GDC 52 and Appendix J, and provide alternative means of assuring the leakage integrity of the NuScale containment. The major containment functional differences are:

The CNV is a high-pressure vessel with no internal subcompartments, an ASME Code Class MC component, constructed to ASME Code Class 1 vessel rules, constructed of all stainless steel clad or stainless materials.

All penetrations are either ASME Code Class 1 flanged joints capable of Type B testing or ASME Code Class 1 welded nozzles with isolation valves capable of Type C testing, or form part of a closed system inside containment.

All flanged joints are designed to remain in contact at accident temperature, concurrent with peak accident pressure.

During refueling, the reactor module, including the CNTS is physically moved by a crane to the refueling area. The upper and lower CNV shells are separated during outages for refueling, maintenance, and inspection. The CNV is designed to

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© Copyright 2016 2018 by NuScale Power, LLC 12 accommodate comprehensive inspections of welds, including volumetric and surface inspections. All welds are accessible, and there are no areas that cannot be inspected. The CNV design allows for visual inspection of the entire inner and outer surfaces. Through-wall degradation can be identified prior to development of potential leak paths precluding this as a credible leakage mechanism.

During reassembly, positive verification is utilized to verify proper stud elongation to ensure proper loading on each flange seal.

During normal operation, the CNV is under a vacuum and is partially submerged in borated water. Automatic engineered safety feature actuation systems initiate on high containment pressure with the CNV still at partial vacuum conditions.

Containment vacuum pressure and leak rate into the CNV is constantly monitored during normal operation. The small containment volume and evacuated operating conditions allows wide-ranging detection capabilities for liquid or vapor in-leakage, providing an additional layer of leakage integrity assurance.

The NuScale CNV design is described in detail in Section 3.0.

2.2 NuScale Containment Vessel Penetrations The NuScale CNTS design supports leakage integrity assurance through inspection and testing other than as required by GDC 52 and Appendix J. When compared to traditional LLWR containments, the NuScale CNTS design is simple. The CNV has a low number of penetrations (40), all of which are either ASME Class 1 flanged joints capable of Type B testing, ASME Class 1 welded nozzles with isolation valves capable of Type C testing, or form part of a closed system inside containment [i.e. steam generator system (SGS) piping]. The CNV has no penetrations equipped with resilient seals. No instrument lines penetrate containment; therefore, there are no small diameter fluid lines without isolation capability that are not subject to Type B or C LLRT. There are no air locks, flexible sleeves, or nonmetallic boundaries. This simplicity of design provides for alternate means of assuring containment leakage integrity. This is primarily achieved by ensuring no unknown leak paths by ISI and accurate leakage rate measurements of all potential leak pathways by LLRT. Key features which ensure NuScale CNTS leakage integrity is maintained include:

CNV flanges are design to remain in contact at accident temperature, concurrent with peak accident pressure.

As described in Section 2.1, the CNV is an ASME Code Class 1 pressure vessel with a relatively low volume and no internal subcompartments. This comparatively simple design (compared to existing LLWR designs) allows for identification of all potential leakage pathways.

The CNV pressure vessel preservice test and inspections are equivalent to RPV requirements, including hydrostatic testing requirements. This verifies that no unknown leakage pathways exist.

preservice design pressure leakage test of the CNV with CNV bolted flanges in place utilizing as-designed flange covers installed with the design bolting materials, design bolting assembly preloads, and design seals installed to demonstrate no observed leakage at design pressureThere are no penetrations in the NuScale CNTS design that would only be tested in a Type A integrated leak rate test (ILRT). This, and other

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the upper and lower halves of the CNV are assembled for the first module of the initial NuScale plant after successful testing, the upper and lower halves of all other CNVs may be tested separately covers with electrical and instrumentation penetrations may be substituted with blank covers having the same sealing design The limited number of CNV penetrations have similar seal designs that are tested by Type B or Type C LLRT. This, and other aspects of the penetration design, allows accurate quantification of the overall leakage rate by LLRT.

The NuScale ISI program and planned CNV examinations will meet ASME Code Class 1 criteria. This ensures that no new unidentified leakage pathways develop over time.

Disassembly and reassembly procedures and controls of the CNV will be similar to the RPV. Positive verification is utilized to verify proper loading on each flange seal.

This ensures that these potential activity-based failure mechanisms do not degrade CNTS leakage integrity.

The CNV is an ASME Subsection NE, Class MC containment designed, fabricated, and stamped as an ASME Subsection NB, Class 1 pressure vessel, with overpressure protection provided in accordance with NE-7000. The CNV is made of corrosion-resistant materials, has a low number of penetrations, and no penetrations have resilient seals. The use of welded nozzles and testable flange seals at the containment penetrations ensure that Type B and C testing provide an accurate assessment of overall containment leakage rate.

The unique CNV and CNTS design allows testing and inspection options not suitable to current LLWR containment designs. Based on the containment vessel ASME pressure vessel design and its function, preferable methods of testing and inspection are available. Each element of NuScales CLIP is consistent with a corresponding element of an approved program for RPVs or LLWR containments.

The NuScale CNTS design is described in detail in Section 3.0. Table 2-1 compares elements of the NuScale CLIP with testing performed on the NuScale containment, RCPB, and traditional containments. The purpose of the table is to demonstrate that the testing is commensurate with the design and safety function of the NuScale containment.

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© Copyright 2016 2018 by NuScale Power, LLC 14 Table 2-1 NuScale containment leak rate test comparison CLIP Program Element to Ensure Essentially Leak-Tight Barrier NuScale Containment Reactor Coolant Pressure Boundary Testing for NuScale and Other Licensed Facilities Traditional Containment Initial verification of structural integrity Hydrostatic testing per ASME Section III Hydrostatic testing per ASME Section III Preservice ILRT Initial verification of leakage integrity Factory - hydrostatic testing per ASME Section III Containment preservice leakage test (ITAAC)

(no measurable visible leakage allowed)

Hydrostatic testing per ASME Section III Preservice ILRT (leakage allowed below prescribed limit)

On-site - preservice LLRT Prevention of leakage from activity-based failure mechanisms (degradation due to system and/or component modifications or maintenance)

Administrative controls such as configuration management and procedural requirements for system restoration that ensure that integrity is not degraded by plant modifications or maintenance activities Administrative controls such as configuration management and procedural requirements for system restoration that ensure that integrity is not degraded by plant modifications or maintenance activities Administrative controls such as configuration management and procedural requirements for system restoration that ensure that integrity is not degraded by plant modifications or maintenance activities Detection of leakage from activity-based failure mechanisms LLRT RCS leak test -

operational pressure LLRT Prevention of leakage from age-based failure mechanisms (age-related degradation)

Design and construction requirements for CNV, inspections/

examinations performed in accordance with ASME, section XI, the maintenance rule and regulatory commitments NuScale CNV design allows for comprehensive ISI surface and weld examination Design and construction requirements for RCS, inspections/

examinations performed in accordance with ASME, section XI, the maintenance rule and regulatory commitments RCS leakage detection Design and construction requirements, inspections/

examinations performed in accordance with ASME, section XI, the maintenance rule and regulatory commitments Detection of leakage from age-based failure mechanisms (age-related degradation)

ILRT Post-repair/

modification verification of leakage integrity Hydrostatic testing per ASME Section XI LLRT Hydrostatic testing per ASME Section XI ILRT/LLRT

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© Copyright 2016 2018 by NuScale Power, LLC 17 3.0 NuScale Containment System Design The NuScale CNTS is designed as an ASME Code Class 1 CNV pressure vessel. The simplicity of the NuScale Power Module (NPM) design minimizes the number of containment penetrations required. There are a limited number of ports (7), manways (2), emergency core cooling system (ECCS) pilot valve penetrations (6), and electrical penetration assemblies (EPAs) (11) that all use similar bolted closure double O-ring seal designs. The CNV closure flange separating the upper and lower CNV assemblies uses the same seal design as the RPV and is similar to the port and manway seal design.

There are a limited number of fluid lines penetrating containment (14 total) (see Figure 3-1 and Figure 3-2). Eight fluid line penetrations are protected by dual CIVs, four are protected by a closed-loop SGS and a single secondary system containment isolation valve (SSCIV), and two are protected by a closed-loop inside and outside containment

[SGS and decay heat removal system (DHRS)].

Figure 3-1 Containment vessel head

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© Copyright 2016 2018 by NuScale Power, LLC 18 3.1 Containment Vessel Design Approximately 94 90 percent of the CNV is submerged in the ultimate heat sink (UHS) that removes residual core heat during normal and accident conditions. The CNV has a design pressure and temperature of 1,000 psia and 550 degrees F. The CNV is a steel vessel with relatively low volume (6,144 ft3) compared to other PWR containments and has no internal subcompartments. The design prevents isolated pockets of concentrated gases. The upper portion of the CNV is constructed of low alloy carbon steel with stainless steel cladding on the inside and outside surfaces. The bottom portion of the CNV is constructed of stainless steel. The CNV will be factory fabricated, which facilitates enhanced fabrication quality and testing control.

Figure 3-2 Containment vessel

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© Copyright 2016 2018 by NuScale Power, LLC 19 All CNV nozzles and penetrations are required to be either forged or welded connections; bellows sealed connections (which are common for LLWR containment penetrations) are not used. There are 14 CNV piping penetrations, eight of which are two-inch nominal pipe size (NPS 2) pipe penetrations that require Type C testing. All are isolated with CIVs of identical design and construction. The other six penetrations are main steam, feedwater and DHRS condensate penetrations that are connected to the steam generator (SG), which are not required to be Type C tested in accordance with 10 CFR 50, Appendix J, II.H. There are 11 EPAs on the CNV (Appendix A.1). There are nine ports and manways on the CNV, and there are six ECCS pilot valve penetrations (Appendix A.1). All Type B penetrations, including the CNV closure flange, have a similar seal design; the only difference is the size and model of the O-rings. These penetrations will undergo periodic LLRTs. All penetrations are either ASME Code Class 1 flanged joints capable of Type B testing, ASME Code Class 1 welded nozzles with isolation valves capable of Type C testing, or form part of a closed system inside containment.

There are 40 total CNV penetrations. The CNV closure flange also requires Type B testing. These penetrations are described in Appendix A.

No instrument lines penetrate containment; therefore, there are no small diameter fluid lines without isolation capability that are not subject to Type B or C LLRT. There are no air locks, flexible sleeves, or nonmetallic boundaries. There are no penetrations in the NPM design that would only be tested in an ILRT. Entry into the CNV is precluded during normal operation by personnel safety constraints and most openings will be submerged in the reactor pool. The integrity of the Type B pathways is not expected to be disturbed except when the NPM is in a refueling outage or disassembled for emergent maintenance activities. All Type B and Type C pathways will be tested to CNTS accident peak pressure (Pa). All Type C pathways are designed such that an individual valve can be tested in the same direction in which the valve would perform its safety function.

3.2 Containment Penetrations The CNV is designed to support Type B local penetration pneumatic leak tests to detect and measure leakage across the pressure-retaining, leakage-limiting boundaries that include flange openings (bolted connections) and EPAs. The CNTS penetration designs allow accurate LLRT results used to quantify the overall containment penetration leak rate. The following containment penetrations are subject to preoperational and periodic Type B leakage rate testing:

flanged access openings with bolted connections EPAs ECCS trip and reset valve body-to-bonnet seals CNV closure flange All Type B penetrations are bolted closures that have dual metal O-ring seals with leak detection and testing ports between the seals. All Type B penetration assemblies are designed and constructed to ASME Code Class 1. The CNV closure flange has a similar double O-ring and test port arrangement. All CNV flanges are designed to remain in contact at accident temperature, concurrent with peak accident pressure. Figure 3-3 shows the location of the Type B bolted penetrations (CNV closure flange and ECCS pilot valves not shown).

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© Copyright 2016 2018 by NuScale Power, LLC 23 Figure 3-6 Emergency core cooling system trip and reset valve assembly 3.2.3 Containment Vessel Closure Flange The CNV closure flange allows disassembly of the CNV for refueling, maintenance, testing, and inspection of the NPM. It has a double metal O-ring seal with test port design similar to the RPV flange.

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© Copyright 2016 2018 by NuScale Power, LLC 28 4.0 Preservice Inspection and Testing 4.1 Manufacturing Facility Testing and Inspection The CNV is hydrostatically tested in the factory in accordance with ASME Subsection NB-6000. The water-filled CNV is pressurized to a minimum of 25 percent over design pressure (1,250 psia) for at least 10 minutes. Pressure is then reduced to design pressure (1,000 psia) and held for at least four hours prior to examining for leaks. The acceptance criterion is no leakage indications at the examination pressure (design pressure). Nondestructive examination of the CNV in the factory includes:

All pressure-retaining and integrally-attached materials examination meets the requirements of NB-5000 and NF-5000 using examination methods of ASME Boiler and Pressure Vessel Code Section V.

All clad surfaces are magnetic particle or liquid penetrant examined in accordance with NB-2545 or NB-2546, respectively, of Reference 7.1.7 prior to cladding.

ASME Code Class 1 pressure boundary examinations are in accordance with NB-5280 and IWB-2200 using examination methods of ASME Boiler and Pressure Vessel Code Section V as modified by NB-5111. Preservice examinations shall include 100 percent of the pressure boundary welds.

ASME Code Class MC examinations are subsumed by NB exam requirements. The Class MC examination is in accordance with IWE-2200. In addition, due to the high pressure design of the CNV, the preservice examination requirements of IWB-2200 are applied (Reference 7.1.7).

Final preservice examinations are performed after hydrostatic testing, but prior to code stamping.

4.2 Preservice Design Pressure Leakage Testing A separate preservice design pressure leakage test is performed on the CNV. This test is performed to ensure that the integrated leakage of the CNV meets design criteria. This test is performed on every NuScale CNV and shall contain the following elements:

This test is required under a separate ITAAC.

As-designed flange covers shall be installed with the design bolting materials, design bolting assembly preloads, and design seals installed.

CNV bolted flanges shall be in place. Covers with electrical and instrumentation penetrations may be substituted with blank covers having the same sealing design.

The upper and lower halves of the CNV are assembled for the first module of the initial NuScale plant. After the first CNV for the initial plant is tested successfully, the upper and lower halves of all other containment vessels may be tested separately.

The CNV is pressurized with water to design pressure and no observed leakage shall be visible from any joint.

A COL Item requires the applicant to verify that the CNV design meets the design basis requirement to maintain flange contact pressure at accident temperature.

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© Copyright 2016 2018 by NuScale Power, LLC 29 The test configuration may utilize blanked off pipe ends in place of the containment isolation valves The acceptance criterion is no observed leakage from seals at examination pressure The ECCS trip valve and reset valve body-to-bonnet joint seals are not considered to be a flanged connection and are not included in the preservice design pressure leakage test or containment flange bolting calculation.

4.24.3 Post-installation Testing and Inspection Preservice inspections and local leak rate testing after installation at the plant site verify the leakage integrity of containment, including verification that no degradation of containment leakage integrity occurred during shipping and installation.

4.34.4 Shipping and Receiving Controls In addition to the post-installation testing, 10 CFR 50, Appendix B controls ensure that the leakage integrity assurance, provided by preservice tests and inspections performed in a factory environment, is maintained throughout shipping and receiving processes.

Quality assurance controls in accordance with 10 CFR 50, Appendix B, Section VII, and Section XIII ensure the quality of the CNV and CNV components throughout shipping and receiving operations. Shipping and handling requirements ensure that these activities do not result in damage or deterioration of CNV components. Procurement controls ensure that material and equipment conform to the procurement requirements and design specifications, including verification upon receipt. These quality assurance processes have not yet been established; however, as required by Appendix B, the controls will be included in the quality assurance programs of the manufacturing facility and COL holder with NRC oversight. Typical controls, as described in NQA-1, include:

measures for packaging, shipping, receiving, storage, and handling of items, and for the inspection, testing, and documentation to verify conformance to specified requirements purchased items shall be inspected to verify conformance to specified procurement and design requirements handling, storage, and shipping, of items shall be controlled to prevent damage, in accordance with established procedures for critical, sensitive, or high-value items, specific procedures for handling, storage, packaging, shipping, and preservation for critical, sensitive, or high-value items, specific procedures of special receiving inspection instructions receiving inspection shall verify by objective evidence such features as:

configuration, identification, dimensional and physical characteristics, and freedom from shipping damage

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(Reference 7.1.1), respectively, and ensure that periodic requisite inspection and testing is performed on the CNTS to ensure leakage integrity is maintained. Type B testing is specified in the COL holders ISI plan and Type C testing specified in the COL holders IST plan. Both the ISI and IST programs are an integral part of the CLIP.

5.1 Inservice Inspection of the Containment System The ISI provides an essential function for the CLIP by confirming CNTS integrity and ensuring no new leakage paths are present. Age-based failure mechanisms are prevented and detected through the compact and accessible design of the CNV, along with inspections and examinations performed in accordance with the ASME Code Section XI Division 1 (Reference 7.1.8, hereafter referred to asSection XI). The NuScale CNV is an ASME Code Class 1 vessel. The CNV components are constructed of stainless steel or are clad on interior and exterior surfaces with stainless steel and are fully inspectable. Periodic, comprehensive ISI ensures that a degradation mechanism is detected and addressed before CNV integrity is threatened.

The requirements for inspection of passive components (structures, welds, supports, etc.) are provided in ASME Section XI. The ASME Code defines ISI requirements for ASME Class 1, Class 2, Class 3, and Class MC components. The CNV is classified as a Class MC containment. The CNV is designed, constructed, and inspected to ASME Code Class 1. The ISI program specifies Type B local penetration leak tests, which are pneumatic pressure leak rate tests of the containment penetrations, such as openings, flanges, and EPAs.

5.1.1 Inspection Elements The NuScale primary CNV design is different from traditional containments. The major differences are summarized as:

The CNV is a high-pressure vessel.

The CNV provides the containment heat removal function to transfer decay heat from the fuel to the UHS.

During normal operation, the CNV is under a vacuum and is mostly submerged in borated water.

During refueling, the CNV is physically moved by a crane to the refueling area while loaded with fuel.

The lower CNV is exposed to a higher neutron flux than typical containments.

Although the CNV is a Class MC component, it is being constructed to ASME Class 1 vessel rules.

The inside of the CNV is inaccessible by personnel during startup and normal operation.

The low-alloy portion of the CNV is clad on its inside and outside surfaces.

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© Copyright 2016 2018 by NuScale Power, LLC 32 Based on the high pressure and the safety function of the CNV, NuScale determined that enhanced inspection requirements are needed for the CNV. Therefore, NuScale will inspect the CNV to ASME Class 1 requirements.

The CNV inspection elements are listed in Table 5-2. Several of the CNV inspection elements are similar to those required for the RPV.

5.1.2 Weld Inspection All CIVs are located outside the CNV. The ASME Section XI reduced-ISI requirements for small primary system pipe welds between the CNV and the CIVs are not applied to these welds. Welds between the CNV and the CIVs are ASME Code Class 1 and are inspected with a volumetric and surface exam at each test interval. The CNV design allows comprehensive inspections of welds, including volumetric and surface inspections. All pressure boundary welds are accessible and there are no areas that cannot be inspected.

The basis for a NuScale ISI program for the CNV is shown in Table 5-2, which describes weld inspection locations and requirements. The specified surface, volumetric (ultrasonic), and visual examinations ensure that no new leakage paths are created over the service life of the CNV.

5.1.3 Bolted Flange Pressure Testing All flanges on the CNV and RPV have dual O-rings with a test port between the O-rings to allow for leak testing. Nozzles with flanges are listed in Appendix A.1. All CNV flanges are tested in accordance with 10 CFR 50, Appendix J, Type B criteria.Leak testing the flanges in the CNV meets Type B criteria. The seal design of the RPV flanges is identical to the CNV. Leak testing of the RPV flanges is performed each time they are removed to ensure proper sealing.

With the exception of the main CNV and RPV flange bolting, all bolts are connected to threaded inserts. There are no inspection requirements for the attachment welds for the threaded inserts.

The EPAs are bolted-flange arrangements. The flange seal is leak tested as described in Sections 5.3.1 and 5.3.2. The EPA sheath modules are design and tested to have a negligible leak rate and only require an LLRT for post-maintenance activities. The All EPAs are pressure tested periodically in accordance with 10 CFR 50, Appendix J, Type B criteria. If necessary, an EPA can be removed and to pressure test a glass moduletested. Section 5.3.2 provides additional discussion on EPA design and leakage integrity.

The only pressure-retaining bolting greater than two-inches is in the RPV and CNV main flanges. The RPV and CNV use the same stud and bolt design. The RPV and CNV use the same tools and controls to disassemble and reassemble each vessel. These bolts are inspected per Section XI (Reference 7.1.8) Category B-G-1. Surface examination is performed when bolting is removed. The CNV and RPV main flange bolting is required to be removed and inspected once each interval.

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© Copyright 2016 2018 by NuScale Power, LLC 33 All pressure-retaining bolting in the CNV and RPV two-inches or less in diameter are Section XI Category B-G-2. These bolting assemblies require a VT-1 each interval if removed. This includes all flange bolting in the CNV and RPV.

The RPV and CNV require a leakage test (VT-2),Section XI Category B-P, at normal operating pressure after each refueling outage. In the NuScale design, leakage is continuously monitored in the CNV. This leakage monitoring is used to meet VT-2 exam requirements according to Section XI IWA-5241(c). During normal operation, the CNV is in a vacuum, so leakage would be from the pool to the inside of the CNV. The CNV leak detection system is able to detect leakage from both the RPV and CNV during normal operation.

5.1.4 Visual Inspections The ASME Code Class MC, Section IWE, requires only visual examination for structures, systems, and components subject to normal degradation and aging.

However, based on the high pressure and safety functions of the CNV, the NuScale ISI program requires the CNV to meet ASME Code Class 1 requirements similar to the RPV.

The CNV design allows visual inspection of the entire inner and outer surfaces; therefore, developing an undetected leak through the metal pressure boundary is unlikely.

5.1.5 Steam Generator Inspections and Controls The SG forms part of a GDC 57 closed-loop containment barrier for PWRs; therefore, its integrity and its failure mechanisms contribute to the integrity of the containment boundary. The NuScale SG design is different from traditional SGs. Major differences include:

The SG is located inside the RPV; it is not a separate component attached by RCS piping.

The tubes are helically coiled in the annular space around an upper riser.

Steam is generated on the inside of the tubes; lower pressure is on the tube interior.

The SG is a GDC 57 closed-loop system isolated by single SSCIVs (MSIV and bypass valve, FWIV). The SG is an ASME Code Class 1 RCPB. Detailed inspection requirements for the SG tubing and tube-to-tube sheet welds are part of the ISI program.

An SG program is established in NuScale DCA Part 4, Technical Specification 5.5.4 to ensure that SG tube integrity is maintained.

5.1.6 Type B Testing Type B testing is local pneumatic pressure leak rate testing of containment penetrations in accordance with 10 CFR 50 Appendix J, such as EPAs, ports, manways, ECCS pilot valve bodies, and the CNV closure flange. It is an ISI test that is specified in the COL holders ISI plan. The NuScale ISI program specifies Type B LLRTs (Table 5-2).

Table 5-2 is a summary of test and inspection elements in the NuScale ISI program for the CNV.

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

© Copyright 2016 2018 by NuScale Power, LLC 34 Table 5-2 Summary of test and inspection elements Description Exam Category Examination Method CNV shell and head welds B-A Volumetric CNV support welds B-A, B-K, F-A Surface, volumetric CNV nozzle-to-shell welds B-D Volumetric or not required per B-D, Note 1 Nozzle-to-safe end dissimilar metal welds Note: Safe end is a short length of Class 1 pipe that is welded between the forged CNV pipe penetration and the CIV body.

B-F Surface and volumetric, surface ECCS pilot valve body to safe end welds B-J Exempted by IWB-1220 due to small size PSCIV (GDC 55) body to safe end welds B-J Surface and volumetric Exemption per IWB-1220 due to small size not applied PSCIV (GDC 56) body to safe end welds C-F-1 Surface Exemption per IWB-1220 due to small size not applied SSCIV body to safe end welds C-F-1 Surface and volumetric Decay heat removal inner and outer safe end-to-piping welds C-F-1 Surface and volumetric CNV ports, manways, EPAs and ECCS pilot valve body-to-bonnet seals Appendix J Type B

Pneumatic leakage CNTS leakage test B-P VT-2 Required for all pressure retaining components CNV exterior surface N/A VT-3 for wetted surfaces General visual for surfaces that are normally dry. Based on the requirements from IWE-2500-1 (E-A).

CNV interior surfaces B-N-1 VT-3 Pressure retaining bolting material, greater than two inches B-G-1 Volumetric Pressure retaining bolting, two inches or less B-G-2 VT-1

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

© Copyright 2016 2018 by NuScale Power, LLC 36 not opened and no bolts were manipulated, and if the as-found test was within CLIP acceptance criteria, then no further tests on that penetration are necessary.

The CNV flange is tested twice after it is reassembled. The first time will be in the refueling area to ensure the new CNV flange O-rings are installed properly and are sealed. The as-left test occurs after the NPM is moved to the operating bay. The as-left test ensures that CNV movement had no adverse effect on the CNV flange seal. After the CNV closure flange seal is tested, then the CNV head manway cover can be reinstalled and tested.

5.3.2 Electrical Penetration Assemblies The EPA sheath modules are installed and tested at the factory. Glass-to-metal seals (penetrations), exclusive of the flange-to-nozzle seals, are designed for leakage rates not to exceed 1.0 x 10-3 standard cm3/s (1.27 x 10-4 SCFH) of dry nitrogen at design pressure and at ambient temperature, including after any design basis event (Reference 7.1.11). Glass-to-metal seals typically achieve leak rates in the undetectable range, 1.0 x 10-7 standard cm3/s of dry nitrogen at design pressure and at ambient temperature. The glass-to-metal module seal is an established sealing technology that is not vulnerable to thermal or radiation aging and does not require periodic maintenance or testing. The module-to-EPA seal does not require periodic testing. It would only be tested after completing maintenance activities that affect the seal. The EPA flange seal is the same double O-ring seal design of all Type B penetration seals. The required installation acceptance criterion for leakage rate of each EPA is 1.0 x 10-2 standard cm3/s (1.27 x 10-3 SCFH) per Reference 7.1.11. The leakage margin allotment for Type B testing is preliminarily selected to be 50 times the installation acceptance criterion. This leakage margin for EPA contribution to overall containment leakage supports maintaining overall containment leakage to less than (0.60) La.

5.3.3 Ports and Manways All CNV access port seals and manway seals are the identical double O-ring design. The leakage performance of these seals is expected to be similar to the EPAs based on an evaluation of leakage performance for off-the-shelf metal seals.

5.3.4 Emergency Core Cooling System Pilot Valve Bodies There are six NPS 3 containment penetrations for the ECCS trip and reset valve assemblies. The valve bodies normally form part of the RCPB and aA Type B test is required at the double O-ring seal between the valve bonnet and body (see Figure 3-6).

The rest of these valve bodies are self-contained metal barriers that form part of the containment pressure boundary. Leakage criteria for these seals is small compared to the other Type B boundaries due to the smaller size of the seals.

5.3.5 Containment Vessel Flange The CNV closure flange is a large double O-ring design (~45-foot circumference). This seal maintains the containment boundary between upper and lower CNV assemblies (see Figure 3-2). The CNV closure flange leakage limit for the CLIP is estimated to be 0.4-0.5 SCFH based on the linear seal length and performance of off-the-shelf metal seals.

NuScale Containment Leakage Integrity Assurance Technical Report TR-1116-51962-NP Draft Rev. 01

© Copyright 2016 2018 by NuScale Power, LLC 39 Figure 5-1 Primary system containment isolation valves Type C testing 5.4.4 Secondary System Containment Isolation Valves There are no Type C leak test requirements for the feedwater isolation valves, MSIVs, and main steam isolation bypass valves. These valves do have specific leakage criteria for DHRS operability. Leak testing of these valves is in accordance with the technical specifications and the IST Program to maintain DHRS operability.

There are two thermal relief valves on the steam generator lines inside containment.

These valves provide thermal overpressure protection during potential solid water conditions during module startup and shutdown. These valves are GDC 56 boundaries and do require a Type C test in the reverse direction (through the valve outlet on top of the valve seat).

5.5 Containment Leakage Rate Test Program The COL holders CLIP contains the following attributes:

Apply limits established in the plant design basis and the technical specifications to establish LLRT criteria to ensure all penetrations meet the preservice and periodic limit of (0.60) La at Pa for the combined leakage rate of all penetrations and valves subject to Type B and C testing.

Perform Type B LLRT testing in accordance with the ISI Program frequency.

Perform Type C LLRT testing in accordance with the IST Program frequency.

Document results of applicable ISI on the CNTS.

Document results of as-found and as-left Type B and C LLRTs.

Document post-work testing results on Type B and C pressure boundaries.

Analyze adverse conditions for generic considerations. All Type B seals are the same double O-ring design, and all Type C valves are the identical, two-inch,

Response to Request for Additional Information Docket No.52-048 eRAI No.: 9474 Date of RAI Issue: 04/23/2018 NRC Question No.: 06.02.06-23 The regulatory bases for the question below are:

10 CFR 52.47, Contents of Applications; technical information, (a) The application must contain a final safety analysis report (FSAR) that describes the facility, presents the design bases and the limits on its operation, and presents a safety analysis of the structures, systems, and components and of the facility as a whole, and must include the following information: (2) A description and analysis of the structures, systems, and components (SSCs) of the facility, with emphasis upon performance requirements, the bases, with technical justification therefor, upon which these requirements have been established, and the evaluations required to show that safety functions will be accomplished. The description shall be sufficient to permit understanding of the system designs and their relationship to the safety evaluations.

This is a followup to RAI 271-9147, question 6.2.6-12.

This is a followup question to the NuScale response to the 12 Feb 2018 clarification call on question 6.2.6-12, in which staff asked where in the FSAR it was stated that the factory CNV hydrotest would be performed on an assembled containment vessel. NuScale responded that FSAR Section 6.2.1.6 states: "The CNV is hydrostatically tested in accordance with ASME BPVC Section III, Subsection NB-6000". This is an accurate quote from the FSAR. However, the ASME Code Section III, Subsection NB-6000 does not require hydrostatic testing of an assembled vessel.

NuScale is requested to confirm that the factory hydrotest of the CNV will be performed on an assembled containment vessel with the same bolting materials, same bolt preload tensioning and same double O-rings seals specified in the design. NuScale is requested to provide a description of the assembled CNV, and to state in FSAR section 3.8.2, FSAR section 6.2.6, NuScale Containment Leakage Integrity Assurance Technical Report, TR-1116-51962, Rev. 0, NuScale Nonproprietary

and NuScale ASME Design Specification for Containment Vessel, EQ-A013-1826, rev 1, that the factory hydrostatic test for the CNV will be performed on an assembled containment vessel.

NuScale is requested to add to FSAR Tier 1, section 2.1 Nuclear Power Module, an ITAAC for the ASME Code requirement for the factory hydrostatic test to be performed successfully, i. e.

showing zero leakage, on an assembled CNV as described in the above documents.

NuScale Response:

Confirmation of the preservice design pressure leakage test:

The preservice design pressure leakage test is similar to the ASME BPVC Section III, Subsection NB-6000 hydrostatic test; however, it is a separate test, specifically designed for verifying containment flange leakage integrity identified by a seperate, design-specific ITAAC requirement that has been added. The preservice design pressure leakage test is described below.

Description of assembled CNV test and documentation:

Each CNV undergoes a preservice design pressure leakage test which tests Type B seals under design preload at CNV design pressure. The preservice design pressure leakage test is performed with the containment vessel filled with water, similar to a hydrostatic test. The preservice design pressure leakage test of the initial as-built containment vessel is performed on an assembled containment vessel using the as-designed flange covers, installed with the design bolting materials, design bolting preloads and design flange covers installed. Covers with electrical and instrumentation penetrations may be substituted with blank covers having the same bolting and sealing design as the inservice covers. The test configuration may utilize blanked off pipe ends in place of the containment isolation valves. The upper and lower halves of subsequent containment vessels may be tested separately. The acceptance criterion is no observed leakage from seals at examination pressure.

Each ECCS trip valve and reset valve contains a body-to-bonnet joint that is also subject to Type B test requirements. The body-to-bonnet seal is designed for RCS design pressure. This seal is tested to meet both Type B and RCPB criteria every refueling outage. These body-to-bonnet seals are not included in the preservice design pressure leakage test.

A general description of the preservice design pressure leakage test, including the above assembled vessel description is provided in FSAR Section 3.8.2, FSAR section 6.2.6, and TR-1116-51962.

NuScale Nonproprietary

Proposed ITAAC requirements:

The following new ITAAC # 23 is proposed:

Design Criteria The CNV serves as an essentially leaktight barrier against the uncontrolled release of radioactivity to the environment.

Inspections. Tests, Analyses A preservice design pressure leakage test of the CNV will be performed.

Acceptance Criteria No water leakage is observed at CNV bolted flange connections.

Additionally, conforming changes are also made to FSAR Tier 2, Section 6.2.6 and Table 14.3-1.

Impact on DCA:

FSAR Tier 1 Section 2.8 and Tier 2 Sections 6.2.6 and 14.3 have been revised as described in the response above and as shown in the markup provided in this response.