ML25051A313

LLC Submittal of FSAR Changes Supporting Aircraft Impact Assessment Updates

ML25051A313
Person / Time
Site:	05200050, 99902078
Issue date:	02/20/2025
From:	Shaver M NuScale
To:	Office of Nuclear Reactor Regulation, Document Control Desk
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ML25051A312	List: ML25051A313
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LO-179665
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LO-179665 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com February 20, 2025 Docket No. 052-050 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738

SUBJECT:

NuScale Power, LLC Submittal of FSAR Changes Supporting Aircraft Impact Assessment Updates The purpose of this letter is to provide the NuScale Power, LLC (NuScale) FSAR changes supporting Aircraft Impact Assessment (AIA). The attachments to this letter contain NuScales FSAR changes in Section 1.2 and Section 19.5 that will be incorporated into the next revision of the Standard Design Approval Application (Revision 2). There is a nonpublic and public version of the attachment that contains the following change packages:

CP-4107 for Chapter 19.5 CP-4108 for Chapter 19.5 CP-4125 for Chapter 1.2 The nonpublic version of the NuScale changes contain Security Related Information (SRI).

NuScale requests the nonpublic version be withheld from public disclosure in accordance with the requirements of 10 CFR § 2.390.

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

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

I declare under penalty of perjury that the foregoing is true and correct. Executed on February 20, 2025.

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

Mahmoud Jardaneh, Chief, New Reactor Licensing Branch, NRC LO-179665 Page 2 of 2 02/20/2025 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com Getachew Tesfaye, Senior Project Manager, NRC Alina Schiller, Project Manager, NRC Stacy Joseph, Senior Project Manager, NRC

LO-179665 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com

FSAR Changes Supporting Aircraft Impact Assessment Updates CP-4107 for Chapter 19.5, Nonpublic Version CP-4108 for Chapter 19.5, Nonpublic Version CP-4125 for Chapter 1.2, Nonpublic Version

LO-179665 NuScale Power, LLC 1100 NE Circle Blvd., Suite 200 Corvallis, Oregon 97330 Office 541.360.0500 Fax 541.207.3928 www.nuscalepower.com

FSAR Changes Supporting Aircraft Impact Assessment Updates CP-4107 for Chapter 19.5, Public Version CP-4108 for Chapter 19.5, Public Version CP-4125 for Chapter 1.2, Public Version

LO-179665 CP-4107 for Chapter 19.5, Public Version

NuScale Final Safety Analysis Report Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts NuScale US460 SDAA 19.5-9 Draft Revision 2 RAI 10107-R1 19.5-2 Figure 19.5-1: General Arrangement Reactor Building Equipment Door

(( Withheld - See Part 9

LO-179665 CP-4108 for Chapter 19.5, Public Version

NuScale Final Safety Analysis Report Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts NuScale US460 SDAA 19.5-2 Draft Revision 2 19.5.3 Assessment Methodology The methodology in NEI 07-13 is used to assess effects of aircraft impact on the structural integrity of the RXB and to evaluate the physical, vibration, and fire effects on SSC in the RXB to ensure continued core cooling and spent fuel cooling capability or integrity. 19.5.3.1 Structures of Concern Structures of concern are those structures that contain SSC necessary to ensure adequate cooling of the fuel in the reactor cores and spent fuel pool (SFP). All six NuScale Power Modules (NPMs), the ultimate heat sink (UHS), and the SFP are located inside the RXB. Containment is integral to each NPM. The 10 CFR 50.150(a) functions are accomplished if the RXB resists the impact loading, prevents wreckage from perforating exterior steel composite walls of the RXB, and prevents pressurized or propagated fire from entering SC I areas of the RXB. The assessment credits the design and location of fire barriers, as depicted in Figure 1.2-8 through Figure 1.2-15, to limit effects of internal fire in the RXB and preserves functions required by 10 CFR 50.150(a)(1)(i) and 10 CFR 50.150(a)(1)(ii). Therefore, the RXB is a building of concern. The Control Building (CRB) is a building of concern prior to an imminent aircraft impact because core cooling is accomplished by operator control actions upon notification of a threat. Section 1.2 addresses key design features of the RXB. 19.5.3.2 Impact Locations Below-grade portions of the RXB are not susceptible to a direct impact by an aircraft. Based on NEI 07-13 (Reference 19.5-1) screening criteria, there are no adjacent structures or buildings credited as intervening structures for the AIA. No credit is taken for the Radioactive Waste Building (RWB), CRB or the Turbine Generator Building (TGB) as intervening structures. All RXB elevations and faces above grade are vulnerable. 19.5.3.3 Assessment of Effects on Fuel Cooling Equipment To assess the effects on fuel cooling equipment, physical damage, shock damage, and fire damage footprints are overlaid on the RXB general arrangement drawings. Fuel cooling equipment that is within these damage footprints is assumed to lose the ability to perform its function due to the associated physical, shock, or fire effects. The remaining fuel cooling equipment is evaluated to determine if adequate cooling of fuel is maintained in the reactors and SFP.

NuScale Final Safety Analysis Report Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts NuScale US460 SDAA 19.5-3 Draft Revision 2 19.5.4 Assessment Results 19.5.4.1 Physical Damage Audit Question A-19.5-4S RAI 10107-R1 19.5-2, 19.5-3, 19.5-4, 19.5-5 The RXB external walls resist physical damage from postulated aircraft strikes. The design of the RXB as described in Section 3B.2 is a key design feature. The design of the RXB equipment door as described in this section is a key design feature for protecting core cooling equipment from impacts through the RWB trolley bay. The RXB equipment door consists of two doors (Figure 19.5-1). The outer door (impact door) serves as a barrier for aircraft impact and other design basis conditions. (( }} An inner door (blast door) serves primarily for security, airtightness, blast, fire, flood, and other design-basis conditions. The impact door is designed to be wider on each side of the blast door framing to support bearing on the SC walls. Procedural controls minimize the amount of time the RBED is open to ensure a low likelihood of exposure to an aircraft impact. Local reinforcement is provided as required at the wall to slab connection at the 146 ft 6 in. elevation. Additional concrete slab reinforcement is provided as required to strengthen the wall to slab connection at the (( }}. The slab reinforcing dowels into the SC walls on column lines RX-B and RX-D to fully develop the reinforcing strength at the RC slab to SC wall connection during an aircraft impact strike. This is a key design featureThe reinforcing of the SC wall to reinforced concrete (RC) slab connections are a key design feature at RXB (( }}. Local detailing in the wall to wall connection region as required using ties is a key design feature. (( }}. Local detailing with tie rods spaced horizontally and vertically in SC wall to SC wall connection region as required at postulated aircraft strike locations is a key design feature. The connection of the (( }} SC walls using shear tie plates, the reinforced knuckle, and the continuation of internal face plate along with studs are key design features. The ties are required above the (( }} of the RXB. The structural beam seat connections of roof beams on 187 ft elevation are key design features.The structural steel beam seat connections that connect the roof beams to the SC walls (( }} are key design features. The beam seats support the steel beams from the bottom of the beams.

NuScale Final Safety Analysis Report Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts NuScale US460 SDAA 19.5-4 Draft Revision 2 RAI 10107-R1 19.5-6 The design of the Reactor Building penetration and piping protections are key design features for preventing physical damage and fire from damaging equipment necessary to fulfill requirements of 10 CFR 50.150(a)(1)(i) and 10 CFR 50.150(a)(1)(ii)entering the RXB. The exterior wall penetration protection (awning) is designed and constructed to provide strength to prevent perforation due to a direct aircraft strike. The exterior wall penetration protections are constructed of 7000 psi concrete with two #11 bars at 12 inches on each face of the awning and each way (horizontal and vertical directions). In addition, the awning protection has #5 shear ties at 12 inches on center. The pipe penetration protections are located at exterior wall penetrations above grade, primarily where main steam and feedwater pipes exit the RXB. Figure 1.2-17 shows the RXB north and south section view. The NEI 07-13 criteria (Reference 19.5-1) are used to minimize physical damage from strikes to external openings in the RXB external walls. Doors and penetrations leading into SC I portions of the RXB are protected to prevent physical damage and fire from an aircraft impact from entering SC I portions of the RXBdamaging equipment necessary to fulfill requirements of 10 CFR 50.150(a)(1)(i) and 10 CFR 50.150(a)(1)(ii). RAI 19.5-7 The trolley on the Reactor Building crane (RBC) cannot be struck and dislodged, because there is no perforation of the RXB outer wall. The design of the RBC, as described in Section 9.1.5, is a key design feature for ensuring that impact loads from an aircraft impact on the exterior wall of the RXB do not result in the crane falling into the reactor pool area and damaging the NPMs or damaging the RXB structure containing the UHS. The size of the crane rail support corbels is a key design feature that provides secondary protection for supporting crane girder dislodgement. The design and location of the RBC as described in Section 9.1.5 is a key design feature for protecting the NPMs. 19.5.4.2 Shock Damage The impact of a commercial aircraft on the RXB structure causes a short duration, high acceleration, high frequency vibration. Shock damage distances are measured from the center of the initial impact along a structural pathway to affected equipment. Shock effects do not affect the spent fuel pool structure nor the ability to retain the pool water inventory. The NPMs are shut down by operator action before impact, and core cooling is provided by passive systems (e.g., the decay heat removal system (DHRS)). There are no SSC susceptible to shock (sensitive electronics or active components) on the NPMs that interrupt or prevent successful core cooling once the reactor is tripped, the DHRS is actuated, and containment is isolated. There is no impact of concern below the 55 ft elevation. The SFP cooling equipment is located on elevation 55 ft and 70 ft of the RXB. Other aAffected

NuScale Final Safety Analysis Report Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts NuScale US460 SDAA 19.5-5 Draft Revision 2 equipment at the 55 ft, 70 ft, 85 ft, 100 ft, 126 ft, and 146 ft 6 in. elevations is not required to maintain core cooling or spent fuel pool integritycooling. 19.5.4.3 Fire Damage The design and location of three-hour fire barriers and three-hour, 5-psid fire barriers, including walls, floors, fire dampers, doors, equipment access door, and penetration seals in the RXB are key design features for the protection of core cooling equipment from the impact of a large commercial aircraft. The assessment credits the design and location of fire barriers, as depicted in Figure 1.2-8 through Figure 1.2-15, to limit effects of internal fire in the RXB to non SC I areas, where there is no equipment required to maintain core cooling. In addition, the design and location of 5-psid blast dampers in the Reactor Building HVAC system air intakes and exhaust lines (described in Section 9.4.2) are key design features. These key design features ensure that necessary core cooling equipment is protected from fire damage for postulated strikes. 19.5.5 Assessment of Acceptance Criteria 19.5.5.1 Containment Intact The containment system (CNTS) is an integral part of the NPM and provides primary containment for the reactor coolant system (RCS). The CNTS includes the containment vessel (CNV), CNV supports, containment isolation valves, passive containment isolation barriers, and containment instruments. The CNV is an evacuated pressure vessel described in Section 3.1.5, Section 3.8.2, and Section 6.2.1. The CNV is maintained partially immersed in a below-grade, borated-water-filled, stainless-steel lined floor, reinforced concrete (RC) basemat and slabs and steel-plate composite (SC) pool walls to facilitate heat removal. The containment remains intact if the ultimate pressure capability of the CNV, as described in Section 3.8.2, is not reduced as a result of the aircraft impact. As stated in Section 19.5.4, there is no physical damage or fire damage to equipment required for fuel cooling in the NPM, including the CNTS. Far shock reaches the CNTS, but there are no components necessary for maintaining the containment intact that would be affected. Therefore, the containment remains fully intact. The design of the CNTS, as described in Section 6.2.1 through Section 6.2.4, shown on Figure 1.2-3, are key design features for maintaining an intact containment. 19.5.5.2 Core Cooling The NPM, described in Section 4.1 is a self-contained nuclear steam supply system comprised of a reactor core, a pressurizer, and two steam generators integrated within the reactor pressure vessel and housed in a compact steel containment vessel. The RCS, as described in Section 5.1 is a subsystem of the

NuScale Final Safety Analysis Report Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts NuScale US460 SDAA 19.5-7 Draft Revision 2 system, as described in Section 4.6 is a key design feature for ensuring a scram can be initiated after impact if the reactor is not scrammed before impact. 19.5.5.3 Spent Fuel Pool Integrity RAI 10107-R1 19.5-7 The east, west, and south SFP walls are constructed as described in Section 3B.2. The design uses SC interior and exterior walls and RC basemat and slabs. The foundation of the SFP is constructed as described in Section 3.8.5. The reinforced concrete floor has a stainless steel liner as described in Section 3.8.4. The SFP is integrated into the RXB structure and is located below grade. Because the SFP is completely below grade, an aircraft impact cannot strike the pool or the pool liner. Thus, the pool liner is not a key design feature. Because there is no damage to the pool structure, there is no loss of water level and SFP integrity is maintained. The location of the SFP, as described in Section 9.1.2 and shown on Figure 1.2-8 through Figure 1.2-15, is a key design feature for maintaining SFP integrity from a direct aircraft impact. There are multiple hoist systems inside the RXB that can be operated over the SFP area: the fuel handling machine, the new fuel jib crane, and the new fuel elevator. The reactor building crane is designed to the ASME standards specified in Table 9.1.5-1. There are seismic restraints on the RBC, as shown on Figure 9.1.5-1. Because the exterior wall of the RXB is not perforated, the trolleys cannot be dislodged to fall into the reactor pool. Additionally, there are seismic restraints on the fuel handling machine, as described in Section 9.1.4. The design and location of the fuel handing equipment and reactor building crane, are key design features for ensuring the hoists remain intact and cannot fall into the SFP. 19.5.5.4 Spent Fuel Pool Cooling Spent fuel pool cooling is not maintained for the postulated strike locations due to shock or to loss of power. However, as described in Section 19.5.5.3, SFP integrity is maintained, and SFP cooling is not required for beyond the mission time, even with the loss of forced SFP cooling. The SFP is part of the ultimate heat sink, which provides water inventory and ensures an adequate water level is maintained above the spent fuel assemblies. 19.5.5.5 Plant Monitoring and Control For the postulated aircraft impact event, required operator actions occur before the aircraft impact, upon notification of the threat. Operators trip the individual NPMs and initiate containment isolation and decay heat removal systems. Following the aircraft impact event, monitoring functions are expected to remain available. However, in the event that post-aircraft impact monitoring is determined to be unavailable, mitigating strategies for the loss of large area (LOLA) beyond-design-basis event are invoked. The actions taken by the operators before the aircraft impact ensure that the reactor core and spent fuel remains cooled, containment remains intact, and spent fuel pool integrity is maintained.

LO-179665 CP-4125 for Chapter 1.2, Public Version

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-23 Draft Revision 2 Figure 1.2-8: Reactor Building 25'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-24 Draft Revision 2 Figure 1.2-9: Reactor Building 40'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-25 Draft Revision 2 Figure 1.2-10: Reactor Building 55'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-26 Draft Revision 2 Figure 1.2-11: Reactor Building 70'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-27 Draft Revision 2 Figure 1.2-12: Reactor Building 85'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-28 Draft Revision 2 Figure 1.2-13: Reactor Building 100'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-29 Draft Revision 2 Figure 1.2-14: Reactor Building 126'-0" Elevation (( Withheld - See Part 9 }}

NuScale Final Safety Analysis Report General Plant Description NuScale US460 SDAA 1.2-30 Draft Revision 2 Figure 1.2-15: Reactor Building 146'-0" Elevation (( Withheld - See Part 9 }}}}