ML18275A351

ABWR DC Renewal SER Sect 19G-5 Aia Evaluation

ML18275A351
Person / Time
Site:	05200045
Issue date:	11/15/2018
From:	James Shea NRC/NRO/DLSE
To:
Shea, James
Shared Package
ML18275A167	List: ML18275A177 ML18275A351
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Download: ML18275A351 (19)

Text

19.0 SEVERE ACCIDENTS 19.4 Not Used 19.5 Aircraft Impact Assessment 19.5(A) Introduction Title 10 of the Code of Federal Regulations (10 CFR) 52.59(a), Criteria for renewal, states, in part, that the first time the Commission issues a rule granting the renewal for a standard design certification in effect on July 13, 2009, the Commission shall find that the renewed design complies with the applicable requirements of 10 CFR 50.150. The ABWR DC for which GEH is requesting renewal was in effect prior to July 13, 2009. Therefore, the applicant proposed design changes to address these requirements.

The impact of a large, commercial aircraft is a beyond-design-basis event (BDBE). Under 10 CFR 50.150, Aircraft impact assessment, renewal applicants for new nuclear power reactors are required to perform a design-specific assessment of the effects on the facility of the impact of a large, commercial aircraft. Applicants are required by 10 CFR 50.150(b) to submit a description of the design features and functional capabilities identified as a result of the assessment in its design control document (DCD), along with a description of how the identified design features and functional capabilities show that the acceptance criteria in 10 CFR 50.150(a)(1) are met.

The Statement of Considerations for the aircraft impact assessment (AIA) rule regarding new nuclear power reactors states that: The NRCs decision on an application subject to 10 CFR 50.150 will be separate from any NRC determination that may be made with respect to the adequacy of the impact assessment which the rule does not require be submitted to the NRC. Since the AIA is not submitted to the NRC for its review, the staff conducts its DC review to determine whether or not descriptions of the design features and functional capabilities are complete enough such that, assuming the design features and functional capabilities perform their intended functions, there is reasonable assurance that the acceptance criteria in 10 CFR 50.150(a)(1) can be met.

This ABWR DC renewal safety evaluation report (SER) section supplement describes the staffs evaluation of the applicants ABWR DCD Tier 2, Section 19G, Revision 6, Aircraft Impact Assessment, and proposed changes to Revision 6 of the ABWR DCD, referred to hereinafter as ABWR DCD Revision 6 Markups (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17059C522).

19.5(B) Regulatory Criteria As described in Section 19.5(A) of this SER, 10 CFR 52.59(a) and 10 CFR 50.150 require renewal applicants to perform a design-specific assessment of the effects on the facility resulting from the impact of a large, commercial aircraft for new nuclear power reactors. The applicant has proposed changes in Revision 6 of the ABWR DCD submitted in 2016, and in ABWR DCD Revision 6 Markups with a description of the design features and functional capabilities identified as a result of the assessment in its DCD, along with a description of how the identified design features and functional capabilities show that the acceptance criteria in 10 CFR 50.150(a)(1) are met. Therefore, in accordance with 10 CFR 52.59(c), this design 19.5-1

change is an amendment, as this term is defined in Chapter 1 of this supplement, and will correspondingly be evaluated using the regulations in effect at renewal.

The staff used the following relevant regulations and guidance to perform this review as described below.

19.5(B).1 Applicable Regulations

• 10 CFR 50.150(a)(1) requires that applicants perform a design-specific assessment of the effects on the facility of the impact of a large, commercial aircraft. Using realistic analyses, the applicant shall identify and incorporate into the design those design features and functional capabilities to show that, with reduced use of operator actions:

(i) the reactor core remains cooled, or the containment remains intact; and (ii) spent fuel cooling or spent fuel pool (SFP) integrity is maintained.

• 10 CFR 50.150(a)(3)(iii)(B) states the requirements of paragraphs (a)(1) and (a)(2) of 10 CFR 50.150 shall apply to applicants for renewal of standard design certifications in effect on July 13, 2009, which have not been amended to comply with the requirements of 10 CFR 50.150 by the time of application for renewal.

• 10 CFR 50.150(b) requires that the final safety analysis report include a description of:

(1) the design features and functional capabilities which the applicant has identified for inclusion in the design to show that the facility can withstand the effects of a large, commercial aircraft impact in accordance with 10 CFR 50.150(a)(1); and (2) how those design features and functional capabilities meet the assessment requirements of 10 CFR 50.150(a)(1).

19.5(B).2 Review Guidance

• Regulatory Guide (RG) 1.217, Guidance for the Assessment of Beyond-Design-Basis Aircraft Impacts, issued August 2011, provides guidance for applicants to demonstrate compliance with NRC regulations with regard to aircraft impact assessment (AIA). In particular, this RG endorses the methodologies described in the industry guidance document, Nuclear Energy Institute (NEI) 07-13, Methodology for Performing Aircraft Impact Assessments for New Plant Designs, Revision 8, dated April 2011.

• NUREG-0800, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants (LWR Edition), Chapter 19.5, Adequacy of Design Features and Functional Capabilities Identified and Described for Withstanding Aircraft Impacts, issued April 2013, provides guidance for meeting the requirements in 10 CFR 50.150(a).

19.5(C) Summary of Technical Information In DCD Tier 2, Section 19G, Revision 6, the applicant states that an AIA was performed in accordance with the requirements in 10 CFR 50.150(a)(1) using the methodology described in NEI 07-13, as endorsed by the NRC in RG 1.217, and SRP Section 19.5. Based on the results of its assessment and staff feedback concerning AIA security-related and proprietary information during a non-public teleconference held January 19, 2017 (ADAMS Accession No. ML17013A018), the applicant identified a set of key design features to show that the 19.5-2

acceptance criteria in 10 CFR 50.150(a)(1) are satisfied. These key design features are reported in DCD Tier 2, Section 19G, Revision 6 and the ABWR DCD Revision 6 Markups, which are based on information submitted in the applicants letter dated February 28, 2017 (ADAMS Accession No. ML17059C517). The February letter contains Technical Report NEDE-33875, Revision 3 (ADAMS Accession No. ML17059C523 public version and ML17059C525 non-public proprietary version), which is incorporated by reference into the application and will be part of the renewed ABWR DC, if approved. In addition, the technical report references other sections of the DCD that provide additional details in support of the ABWR AIA. DCD Tier 2, Section 19G, Revision 6 and ABWR DCD Revision 6 Markups, also contain descriptions of how the key design features show that the acceptance criteria in 10 CFR 50.150(a)(1) are met.

19.5(C).1 Description of Key Design Features As described in the GEH ABWR DCD Tier 2, Section 19G, Revision 6, and ABWR DCD Revision 6 Markups, the credited design features, functions, and references to sections containing the detailed descriptions are summarized below:

DCD Tier 2, Section 19G.4.1, Primary Containment (1) The Reinforced Concrete Containment Vessel (RCCV) as described in DCD Tier 2, Sections 3.8,Seismic Category I Structures, and 3H.1 Reactor Building, protects the safety systems located inside primary containment from the impact of a large commercial aircraft.

DCD Tier 2, Section 19G.4.2, Site Arrangement and Plant Structural design (1) The location and design of the Control Building (C/B) structure as described in DCD Tier 2, Sections 3.8.4, Other Seismic Category I Structures, and 3H.2 Control Building, protect portions of the Reactor Building (R/B) from the impact of a large commercial aircraft. The C/B location, fixed with respect to other major structures, is defined in GEH technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525) to ensure that credit of the C/B as an intervening structure is maintained.

(2) The location and design of the Turbine Building structure and layout as described in DCD Tier 1, Section 2.15.11, Turbine Building, and Tier 2, Figures 1.2-24 through 1.2-31 protect the entire north wall of the C/B and portions of the north wall of the R/B from the impact of a large commercial aircraft. The Turbine Building location, fixed with respect to other major structures, is defined in GEH technical report NEDE-33875P, Revision 3 to ensure that credit of the Turbine Building as an intervening structure is maintained.

(3) The location and design of the R/B structure as described in DCD Tier 2, Sections 3.8.4 and 3H.1, Reactor Building, protect portions of the primary containment and the entire south wall of the C/B from the impact of a large commercial aircraft. This includes the protection provided by exterior walls, interior walls, intervening structures and barriers on the large openings in the reactor building exterior walls. The reactor well shield plugs protect the drywell head from secondary impacts as identified in DCD Tier 2, Section 3H.1.3, Structural 19.5-3

Description. The R/B location, fixed with respect to other major structures, is defined in GEH technical report NEDE-33875P, Revision 3 to ensure that credit of the R/B as an intervening structure is maintained.

(4) The location and design of the SFP and its supporting structure as described in DCD Tier 2, Section 9.1, Fuel Storage and Handling, and Figure 1.2-12, Reactor Building, Arrangement Plan at Elevation 31700/38200 mm, protect the SFP from the impact of a large commercial aircraft.

(5) The physical separation of the Class 1E emergency diesel generators prevents the loss of all electrical power to core cooling systems by protecting them from physical damage, fire damage and smoke effects.

(6) The location and design of the Service Building structure as described in DCD Tier 2, Section 3H.6, Summary of Key Structural Design Features, and Figures 1.2-20 through 1.2-22 protect the east wall of the C/B from the impact of a large commercial aircraft. The Service Building location, fixed with respect to other major structures, is defined in GEH technical report NEDE-33875P, Revision 3 to ensure that credit of the Service Building as an intervening structure is maintained.

(7) The location and design of the Control Building Annex structure as described in DCD Tier 2, Section 3H.6 and Figures 1.2-20 through 1.2-22 protect the west wall of the C/B from the impact of a large commercial aircraft. The Control Building Annex location, fixed with respect to other major structures, is defined in GEH technical report NEDE-33875P, Revision 3 to ensure that credit of the Control Building Annex as an intervening structure is maintained.

(8) The seismic gap between the R/B and C/B described in DCD Tier 2, Section 3.8.5.1, Description of the Foundations, protects the C/B from shock effects from strikes on the R/B.

(9) The R/B Heating Ventilation and Cooling System (HVAC) ducting locations ensure routing maintains separation divisionally through protection or physical separation so that AIA strikes do not result in a loss of all divisions of core cooling.

(10) During normal operating conditions, the R/B crane will be parked at the R/B north wall when not in use.

(11) Any permanent structure that penetrates the C/B roof is sized to preclude a strike from the east and west directions.

19.5-4

DCD Tier 2, Section 3H.6, Summary of Key Design Features (1) Structural configuration of the SFP within the R/B precludes a direct strike on the SFP. The SFP is a reinforced concrete structure with an ASTM A-240 Type 304L stainless steel liner. The SFP walls are strengthened as described in GEH technical report NEDE-33875P, Revision 3 to ensure that the structural integrity of the SFP is maintained.

(2) Structural configuration of the RCCV within the R/B precludes a direct strike on containment, and structural design of RCCV ensures that RCCV is not perforated.

(3) Shield blocks over the drywell head are to be configured to fully resist secondary impact from concrete debris, aircraft wreckage, and falling crane components to protect the integrity of drywell head. The reactor cavity shield blocks are shown in DCD Figure 3H.1-23, Reactor Building Reactor Cavity Shield Blocks.

(4) Interior partition walls are to be thickened and strengthened as shown in GEH technical report NEDE-33875P, Revision 3 to limit physical damage to interior partition walls.

(5) Reinforced Concrete Sliding Barriers with structural capacity equivalent to the surrounding wall are to be provided for the 6 large openings on 1F (DCD Tier 2, Figure 1.2-8, Reactor Building, Arrangement Plan.)

(6) Protective awnings for the HVAC exhaust openings on 2F (DCD Tier 2, Figure 1.2-9, Reactor Building, Arrangement Plan,) sized to provide structural capacity equivalent to the corresponding exterior wall to prevent unabated wreckage through these openings.

(7) Protective awnings for the HVAC intake openings on 3F (DCD Tier 2, Figure 1.2-10, Reactor Building, Arrangement Plan, sized to provide structural capacity equivalent to that provided in Table 3-2 of NEI 07-13, Revision 8 for exterior walls.

(8) Deleted.

(9) Control Building Annex exterior walls to be reinforced concrete.

(10) Service Building exterior wall to be a reinforced concrete.

(11) Turbine Building exterior wall to be reinforced concrete.

(12) R/B exterior walls on the East, West, and South sides to be strengthened with enhanced reinforcement as described in GEH technical report NEDE-33875P, Revision 3.

19.5-5

19.5(C).2 Description of How Regulatory Acceptance Criteria are Met The acceptance criteria in 10 CFR 50.150(a)(1) require the applicant to perform a design-specific assessment of the impact of a large, commercial aircraft on the facility. Using realistic analyses, the applicant shall identify and incorporate into the design those design features and functional capabilities to show that, with reduced use of operator actions: (i) the reactor core remains cooled, or the containment remains intact; and (ii) spent fuel cooling or SFP integrity is maintained.

In DCD Tier 2, Section 19G, Revision 6, and the ABWR DCD Revision 6 Markups, GEH indicates that it meets the 10 CFR 50.150(a)(1) acceptance criteria by including features in the ABWR design that, following the impact of a large commercial aircraft, show that the design can:

• maintain core cooling and

• maintain SFP integrity GEH proposes to maintain core cooling using the safety-related systems described in DCD Tier 2, Revision 6, Section 19G, and the ABWR DCD Revision 6 Markups, which have been designed specifically to ensure that the reactor can be shut down and decay heat adequately removed from the reactor core following the impact of a large commercial aircraft. The key design features and physical separation for assuring core cooling are described in in DCD Tier 2, Section 6.3, Emergency Core Cooling. Some of this equipment is located inside the RCCV and some is located inside the R/B. Locations inside the RCCV are protected from structural, shock, and fire damage by the design of the RCCV structure as well as the R/B structure, which limits the penetration of a large, commercial aircraft such that the RCCV is not perforated. Equipment inside the R/B is protected by structural design features of the R/B itself and by structures adjacent to the R/B, including the T/B, the C/B annex, and the service building. In addition, fire barriers have been designed and located in the R/B to contain the spread of fire inside the building such that at least one train of safety-related equipment for core cooling is protected for each R/B impact scenario.

As for maintaining spent fuel integrity, Section 19G.5 of DCD Tier 2, Revision 6, and the ABWR DCD Revision 6 Markups, indicate that there are no AIA scenarios that would result in perforation of the SFP liner, and that no SFP liner leakage or SFP drain down from piping attachments will result below the required minimum water level.

19.5(D) Technical Evaluation The staff reviewed the AIA information in DCD Tier 2, Revision 6, and the ABWR DCD Revision 6 Markups, Section 19G, Aircraft Impact Assessment, and the referenced DCD sections and evaluated the following:

19.5(D).1 Reasonably Formulated Assessment The applicant states in DCD Tier 2, Section 19G, Revision 6, and the ABWR DCD Revision 6 Markups, that its AIA is based on the guidance provided by RG 1.217 and NRC endorsed NEI 07-13, Revision 8, with no exceptions. The staff also finds that the applicants hired contractors used to perform the AIA were well-experienced and have performed the AIA previously for other design centers.

19.5-6

Together, the staff finds that the applicant adequately meets the guidance in SRP Section 19.5, Items III.1 and 2, because the applicant used an assessment methodology that conforms to the NRC endorsed guidance in NEI 07-13, Revision 8, and the assessment was performed by qualified personnel consistent with the guidance in SRP Section 19.5, Item III.2.

19.5(D).2 Key Design Features for Core Cooling As indicated in DCD Tier 2, Revision 6, Section 19G.4.4, Core Cooling Features, the applicant described the key design features for assuring core cooling. The staffs evaluation of these key design features is documented in other sections of this SER. For example, the Reactor Service Water System is evaluated in SER Section 9.2.15 and the Reactor Building Cooling Water System is described in SER Section 9.2.11. Both of these systems are key design features for providing the necessary cooling water for ABWR Emergency Core Cooling System (ECCS) system operation. The information provided by the applicant was used by staff to confirm that these features are also suitable for maintaining core cooling following the impact of a large commercial aircraft. During the review, the staff also confirmed that all of these design features can be initiated and operated from the control room or an alternate location, and require little, if any, further operator intervention to maintain the core cooling function.

The applicant stated that, following normal power operation, an undamaged ECCS has the capability of maintaining core cooling. In addition to the ECCS, the applicant identified support systems necessary to maintain core cooling. The staff compiled a list of the credited key design features identified in DCD Tier 2, Section 19G in SER Table 19.5, below.

The applicants assessment determined that at least one division of ECCS would be available following the impact of a large commercial aircraft on the R/B. The applicant credited advance warning, consistent with NRC endorsed NEI 07-13, Revision 8, for the operators to take manual action to shutdown the reactor prior to impact. The applicant further described that the hydraulic control units are located below grade, outside of the assessed AIA damage footprint of the ABWR design. The applicant further described that during shutdown conditions (reactor shutdown with the reactor head removed and reactor water level at the level of the vessel flange or higher) administrative controls will be established by the COL applicant to ensure residual heat removal (RHR) Train A and either RHR or high pressure core flooder for Train B and C are not out of service for maintenance until the cavity is flooded. This will ensure an adequate water reservoir to provide cooling of the fuel in the vessel for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

The staff reviewed changes to DCD Tier 2, Revision 6 in a GEH Letter (ADAMS Accession Nos. ML16258A347) dated September 2, 2016, and its supplement (ADAMS Accession No. ML16334A291) dated November 23, 2016. The applicant provided ABWR DCD Revision 6 Markups, drawings, and a technical report necessary to update the ABWR design certification information to the latest AIA. These letters identify additional key design support features for core cooling. For example, the letters state that cabling and ventilation is routed divisionally, and the main control room HVAC mechanical and electrical cross connects are identified as key design features for core cooling. The staff finds the applicants addition of key design features acceptable because it modifies the DCD to contain a description of the design features and functional capabilities as required by 10 CFR 50.150(b). The incorporation of all DCD markups, the Revision 3 GEH letter, and its supplement into the DCD, is being tracked as a Confirmatory Item 19.5-1.

19.5-7

Based on the staffs review of DCD Tier 2, Section 19G, and the applicants use of the NRC endorsed guidance document NEI 07-13, Revision 8, the staff finds that the applicant performed a reasonably formulated analysis in the aircraft impact assessment that identifies key design features necessary for core cooling. Also, based on the above, the staff finds the applicants description of the key design features for maintaining core cooling to be adequate and acceptable, and therefore meets the requirements of 10 CFR 50.150(b).

The staff compiled a complete list of the ABWR key design features in the table below.

SER Table 19.5 - Key Design Features Design Feature DCD Reference Function Sections Fire Barriers: 3-hour fire-rated 9.5.1 Protect core cooling equipment 9A from fire damage Fire Barriers: 3-hour fire-rated, 5-psid 9.5.1 Protect core cooling equipment rated 9A from fire damage Emergency Core Cooling Systems 6.3 Core cooling Reactor Service Water System 9.2.15 Core cooling Reactor Building Cooling Water 9.2.11 Core cooling System Class 1E ac and dc Power Systems 8.3.1; 8.3.2 Core cooling Instrumentation System 7.2; 7.3.2.1; Core cooling 7.3.2.4; 7.3.2.6; 7.3.2.7; 7.3.2.8 AC Independent Water Addition 5.4.7 Core cooling System Control Rod Drive Hydraulic Control 4.6.1 Core cooling Units Ultimate Heat Sink 9.2.5 Core cooling Containment Overpressure Protection 6.2.5 Core cooling System Reactor Safety Relief Valves 6.2 Core cooling Main Control Room HVAC 9.4.1.1.4 Core cooling Reactor Building HVAC 9.4; Core cooling Appendix 9A Makeup Water Condensate System 9.2.9 Core cooling Fire Water Storage System 9.5.1 Core cooling Suppression Pool 6.2.1 Core cooling SFP and Support Structures 9.1 and Figure 1.2-12 SFP Integrity Primary Containment 3.8; 3H.1 Protect core cooling equipment Control Building 3.8.4; 3H.2 Protect core cooling equipment and provide screening for reactor building Design Feature DCD Reference Function Sections 19.5-8

Turbine Building Tier 1 2.15.11; Provide screening for control Figure 1.2-24 building and reactor building through 1.2-31 Control Building Annex 3H.6; Figures Provide screening for control 1.2-20 through building 1.2-22 Service Building 3H.6; Figures Provide screening for control 1..2-20 through building 1.2-22 Reactor Building 3.8.4; 3H.1 Protect core cooling equipment and SFP integrity, and provide screening for the control building 19.5(D).3 Key Design Features that Protect Core Cooling Design Features The key design features and functional capabilities that protect the core cooling design features are described below. These include: fire barriers and fire protection features, plant arrangement and plant structural design features, ability to survive shock-induced vibrations, and ability to trip the reactor.

19.5(D).3.1 Fire Barriers and Fire Protection Features As indicated in DCD Tier 2, Revision 6, Section 19G.4.3, Fire Barrier and Fire Protection Features, the applicant identified and described the fire protection key design features that protect core cooling equipment. These included the design and location of the three-hour fire rated fire barriers and the five psid (34.5 kPa), three-hour fire rated barriers within the R/B. The applicant indicated that the assessment credited the design and location of the R/B fire barriers (including floor assemblies, doors, penetration seals, and dampers) as described in DCD Tier 2, Revision 6, Sections 9.5.1 and 9A.4 (which includes Figures 9A.4-1 through 9A.4-10). These fire barriers limit the effects of internal fires created by the impact of a large commercial aircraft.

The applicant clarified that all credited watertight doors will have a five psid (34.5 kPa), three-hour fire rating. Additionally, all credited penetration seals in 3-hour fire barriers will also be rated for 3-hour, 5-psid. Fire dampers with a 3-hour 5-psid rating will be quick actuating (Blast) type.

In addition, the staff reviewed the fire protection related changes to DCD Tier 2, Revision 6. As a result of preparing for the AIA Inspection, GEH determined that the DCD required additional updating to be consistent with its latest AIA. Therefore, in Revision 0, dated September 2, 2016 (ADAMS Accession No. ML16258A347) and (ADAMS Accession No. ML16334A291),

Revision 2, dated November 23, 2016, the applicant provided DCD Revision 6 markups based on information from technical report NEDE-33875P, Revision 2 (ADAMS Accession No. ML16334A295) that were necessary to update the ABWR DCD with information included in the latest AIA. The Revision 6 DCD Markups based on the update to the AIA technical report, NEDE-33875P, Revision 3, also identified additional editorial changes and additional fire protection key design features that protect the core cooling features. For example, the fire protection related changes include:

• Corrections to room and fire area numbers as well as adjusting rating locations of floor assemblies within DCD Tier 2, Revision 6, Figures 9A.4-3 through 9A.4-8.

19.5-9

• Addition of a new ITAAC in DCD Tier 1, Table 2.15.10, to ensure the R/B steel trusses supporting the roof are encased with five psid (34.5 kPa), three-hour fire rated material.

• Addition of new language under DCD Tier 2, Section 9A.2, to ensure the R/B steel trusses supporting the roof are encased with five psid (34.5 kPa), three-hour fire rated material.

• Addition of new key design feature stating cabling and ventilation routing is designed divisionally.

• Addition of new constraint under DCD Tier 2, Section 19G.4.3-1, stating divisional power, instrumentation or control cabling routed through another space must be assessed under 10 CFR 50.150.

These key design features, as described by GEH, ensure at least one complete train of heat removal equipment and necessary support systems (including cooling water, electrical power supply and distribution, and instrument and control) within the R/B are available to provide core cooling following the impact of a large commercial aircraft.

Based on the addition of the fire protection key design features listed above and the staff review of those additional design features, including those identified in the DCD Revision 6 markups, the staff finds the applicants description of the fire protection key design features for protecting core cooling equipment to be adequate and acceptable in accordance with 10 CFR 50.150(b).

The incorporation of all DCD markups provided in the February 28, 2017, letter and NEDE-33875P, Revision 3 is being tracked as Confirmatory Item 19.5-1.

19.5(D).3.2 Plant Arrangement and Plant Structural Design Features In the DCD Tier 2, Section 19G.4.2, Site Arrangement and Plant Structural Design, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the ABWR plant design and arrangement of major structures as described in DCD Tier 2, Section 1.2, General Plant Description, and Figure 1.2-1, Site Plan, are key design features. The applicant also described key structural design features for aircraft impact in DCD Tier 2, Section 3H.6, Summary of Key Structural Design Features, of the revised ABWR DCD Revision 6 Markups.

Specially, the applicant stated that the AIA credited the arrangement and design of the building features to limit the location and effects of potential aircraft strikes on the R/B, RCCV and C/B.

The staffs review of the design features and functional capabilities of those individual buildings to demonstrate that the acceptance criteria of 10 CFR 50.150(a)(1) can be met are detailed in Sections 19.5(D).3.2.1 through 19.5(D).3.2.7 below.

19.5(D).3.2.1 Location and Design of the Control Building The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the capability of the C/B to protect portions of the north wall of the R/B, and core cooling equipment.

19.5-10

Item (1) in DCD Tier 2, Section 19G.4.2, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the location and design of the C/B structure as described in DCD Tier 2, Sections 3.8.4 and 3H.2 are design features that protect portions of the R/B from the impact of a large commercial aircraft. The staff reviewed general arrangement drawings in DCD Revision 6, Tier 2, Figures 1.2-1, Site Plan, 1.2-14 Control and Service Building, Arrangement, 1.2-15 Control and Service Building, Arrangement, and 1.2-22 Control and Service Building, Arrangement Plan. The staff also reviewed DCD Revision 6, Tier 2, Sections 3.8.4.1.2, Control Building, and 3H.2 Control Building, and confirmed that the north wall of the R/B is protected by the shear walls of the C/B.

The applicant made additional changes in Item (1) to the DCD Tier 2, Section 19G.4.2 to clarify that the C/B location, fixed with respect to other major structures, is defined in the technical report NEDE-33875P, Revision 3, to ensure that credit of the C/B as an intervening structure is maintained. The staff reviewed the relevant drawings (DCD Revision 6, Tier 2, Figures 1.2-1, 1.2-20, Control and Service Building, Arrangement Plan, 1.2-21 Control and Service Building, Arrangement Plan, and 1.2-22 Control and Service Building, Arrangement Plan,) which show the relative relationship of the building locations among the C/B annex, C/B, and R/B structures.

The staff further reviewed DCD Revision 6, Tier 2, Table 3-2, Intervening Structures Credited in ABWR Aircraft Impact Assessment, and Figure 3-1, ABWR Site Plan - Location of Structures, in the GEH technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525),

which show the distance from the intervening structures to the shielded structure. The applicant screened the C/B as an intervening structure based on the criteria set in Section 3.2.2, Screening Based on Intervening Structures, of NEI 07-13, Revision 8. The staff confirmed that the location of the relevant structures is fixed at the design certification stage. On this basis, the staff finds credit of the C/B as an intervening structure acceptable.

The applicant further added new Item (11) to the DCD Tier 2, Section 19G.4.2 clarifying that any permanent structure that penetrates the C/B roof will be sized to preclude a strike from the east and west direction. The applicant described in the technical report NEDE-33875P, Revision 3, that penetrations are not installed on the C/B roof without an AIA cognizant engineer review.

The staff reviewed the DCD Revision 6, Tier 2, Figure 1.2-22, Control and Service Building, Arrangement Plan, and Section 3.5, Functional Success Criteria, in the technical report NEDE-33875P, Revision 3, and found that permanent structure penetrations on the C/B roof in certain areas depend on AIA strike angles and roof penetration sizes. Therefore, the staff finds the design features and the controls established regarding permanent structure penetrations on the C/B roof acceptable.

Based on the above review, the staff finds that the applicants description of the C/B location, design, and its AIA analysis, as described in technical report NEDE- 33875P, Revision 3, protects portions of the R/B from the impact of a large commercial aircraft in accordance with the requirements of 10 CFR 50.150(b). The staff also finds the applicants description of the design features and controls for permanent structure penetrations of the C/B roof to be acceptable and in accordance with the requirements of 10 CFR 50.150(b).

The incorporation of all ABWR DCD Revision 6 Markups of Tier 2, Sections 19G.4.2 and 3H.6, is being tracked as a Confirmatory Item 19.5-1.

19.5(D).3.2.2 Location and Design of Turbine Building 19.5-11

The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the capability of the Turbine Building to protect the entire north wall of the C/B, portions of the north wall of the R/B, and core cooling equipment from the impact of a large commercial aircraft.

In Item (2) of DCD Tier 2, Section 19G.4.2, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the location and design of the Turbine Building structure and layout as described in DCD Tier 1, Section 2.15.11 and Tier 2, Figure 1.2-24 through 1.2-31 are key design features that protect the entire north wall of the C/B and portions of the north wall of the R/B from the impact of a large commercial aircraft. The staff reviewed general arrangement drawings in DCD Revision 6, Tier 2, Figure 1.2-1, and Figures 1.2-24 through 1.2-31. The staff also reviewed DCD Revision 6, Tier 1, Section 2.15.11, Turbine Building, and finds that the Turbine Building is designed such that damage to safety-related functions does not occur under seismic loads corresponding to the safe shutdown ground acceleration. Review of these general arrangement drawings shows that entire north wall of the C/B and portions of the north wall of the R/B are protected by the Turbine Building structure.

The applicant made additional changes in Item (2) to the DCD Tier 2, Section 19G.4.2, to clarify that the Turbine Building location, fixed with respect to other major structures, is defined in the technical report NEDE-33875P, Revision 3 to ensure that credit of the Turbine Building as an intervening structure is maintained. The staff reviewed the relevant drawings (DCD Tier 2, Revision 6, Figure 1.2-1, and Figures 1.2-24 through 1.2-31), which show the relative relationship of the building locations among the Turbine Building, C/B, and R/B structures. The staff further reviewed Table 3-2, Intervening Structures Credited in ABWR Aircraft Impact Assessment, and Figure 3-1, ABWR Site Plan - Location of Structures, in the GEH technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525), which show the distance from the intervening structures to shielded structure. The applicant screened the Turbine Building as an intervening structure based on the criteria set in Section 3.2.2 of NEI 07-13, Revision 8, as endorsed by RG 1.217. The staff confirmed that the location of the relevant structures is fixed at the design certification stage. On this basis, the staff finds the credit of the Turbine Building as an intervening structure acceptable.

The applicant further added new Item (11) to the DCD Tier 2, Section 3H.6 that included details of the Turbine Building reinforced concrete exterior wall adjacent to the Control Building. The applicant described in Table 5-1, Key Structural Design Features in DCD Appendix 3H.6, of the technical report NEDE-33875P, Revision 3 that this is an input to allow credit of the Service Building wall as an intervening structure. The staff reviewed Figures 1.2-1, 1.2-25, Turbine Building General Arrangement, in DCD Tier 2, Revision 6, and Table 5-1 in the technical report NEDE-33875P, Revision 3, and finds it acceptable, because the applicant screened the Turbine Building as an intervening structure based on the criteria set in Section 3.2.2, Screening Based on Intervening Structures, of NEI 07-13, Revision 8, as endorsed by RG 1.217.

Based on the above review, the staff finds the applicants description, including location and design of the Turbine Building structure and layout, as a key design feature for protecting the entire north wall of the C/B and portions of the north wall of the R/B from the impact of a large, commercial aircraft to be acceptable, because the applicant adequately described the above design features and functional capabilities in accordance with 10 CFR 50.150(b).

The incorporation of all ABWR DCD Revision 6 Markups of Tier 2, Sections 19G.4.2 and 3H.6, is being tracked as a Confirmatory Item 19.5.1.

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19.5(D).3.2.3 Location and Design of Reinforced Concrete Containment Vessel and Reactor Building Structure The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the capability of the RCCV and R/B structures to protect the safety systems located inside primary containment and the entire south wall of the C/B from the impact of a large commercial aircraft. The applicant used the guidance provided in NEI 07-13, Revision 8, as endorsed by RG 1.217, to perform detail structural analyses to determine the design of selected structures providing protections from the impact of a large commercial aircraft.

In Item (3) in DCD Tier 2, Section 19G.4.2, as revised in ABWR DCD Revision 6 Markups, the applicant stated that the location and design of the R/B structure as described in Sections 3.8.4, Other Seismic Category I Structures, and 3.H1 Reactor Building, are the key design features protecting portions of the primary containment and the entire south wall of the C/B from the impact of a large commercial aircraft. The applicant further described the protection provided from exterior walls, interior walls, intervening structures, and barriers on the large openings in the R/B exterior walls.

The staff reviewed Sections 3.8.4 and 3.H1 in DCD Revision 6, Tier 2 and finds that the R/B and RCCV are reinforced concrete structures, below grade. Review of these general arrangement drawings (DCD Revision 6, Tier 2, Figure 1.2-1, and Figures 1.2-4 through 1.2-12) shows that the entire south wall of the C/B is protected by the concrete shear walls of the R/B. Further, in DCD Tier 2, Section 19G.2, Scope of Assessment, of the revised ABWR DCD Revision 6 Markups, the applicant states that the SFP and RCCV are not perforated in the event of an aircraft impact based on the assessment results; therefore, assessment of the damage to RCCV internal systems, structures, and components (SSCs) and secondary impact is not required. In addition, the staff reviewed Section 2.0, Analysis Inputs, Section 4.3, Structural Assessment, Table 4-2, Summary of Material Specifications, and Table 4-4, Summary of Strengthening Measures, in the technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525). The staff finds that the applicant performed the assessment for the AIA using the NEI 07-13, Revision 8 methodology, as endorsed by RG 1.217, strengthened measures for the interior and exterior walls based on results of the assessment, and designed external barriers as shown in Figure 1.2-8, Reactor Building, Arrangement Plan, and Figure 1.2-9, Reactor Building, Arrangement Plan, in combination with the external wall protect the critical penetrations. The technical evaluation of the adequacy of the reactor cavity shield blocks for protecting the drywell head from secondary impacts is located in the Section 19.5(D).3.2.7 of this SER.

The applicant made additional changes in Item (3) to the DCD Tier 2, Section 19G.4.2 clarifying that the R/B location, fixed with respect to other major structures, is defined in the technical report NEDE-33875P, Revision 3, to ensure that credit of the R/B as an intervening structure is maintained. The staff reviewed the relevant drawings (DCD Tier 2, Revision 6, Figures 1.2-1, and 1.2-4 through 1.2-12) which show the relative relationship of the building locations among the T/B, C/B, and R/B structures. The staff further reviewed Table 3-2 and Figure 3-1 in the GEH technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525), which show the distance from the intervening structures to shielded structure. The applicant screened the R/B as an intervening structure based on the criteria set in Section 3.2.2 of NEI 07-13, Revision 8, as endorsed by RG 1.217. The staff confirmed that the location of the relevant 19.5-13

structures is fixed at the design certification stage. On these bases, the staff finds credit of the R/B as an intervening structure acceptable.

The applicant added new Item (10) to the DCD Tier 2, Section 19G.4.2 clarifying that the R/B crane will be parked at the North wall of the R/B when it is not used because parking the R/B crane at the North wall of R/B would significantly reduce the probability of the effect of secondary impact from falling crane components on the shield blocks that protects the drywell head from the impact of a large commercial aircraft.

In Item (2) in DCD Tier 2, Sections 3H.6, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the structural configuration of RCCV within R/B precludes direct strike on containment, and structural design of RCCV ensures that RCCV is not perforated. In addition, the applicant described in DCD Tier 2, Section 19G.4.1, of the revised ABWR DCD Revision 6 Markups, that RCCV is a key design feature that would protect the safety systems located inside primary containment from the impact of a large commercial aircraft. The staff reviewed the description of key design features of RCCV in Sections 3.8 and 3.H1 in DCD Revision 6, Tier 2. The staff also reviewed the description of RCCV material specifications in Table 4-2, Summary of Material Specifications, and Section 4.3, Structural Assessment, in the GEH technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525). The staff finds that the RCCV is not perforated in the event of an aircraft impact based on the assessment results; therefore, assessment of the damage to RCCV internal SSCs and secondary impact is not required. In Section 19.5(D).3.2.7 of this SER, the staff independently reviews and assesses the shield blocks protecting integrity of the drywall head from the secondary impacts.

The applicant made additional changes in Item (4) to the DCD Tier 2, Section 3H.6, of the revised ABWR DCD Revision 6 Markups clarifying that the interior partition walls are thickened and strengthened as shown in the technical report NEDE-33875P, Revision 3 to limit physical damage to interior partition walls from the impact of a large commercial aircraft. The staff reviewed general arrangement drawings for the interior partition walls in Figures 1.2-8 and 1.2-9 in DCD Revision 6, Tier 2. The staff also reviewed the description of thickened and strengthened internal partition walls in Table 4-4 in GEH technical report NEDE-33875P, Revision 3. The staff finds that the interior partition walls are appropriately thickened and strengthened based on the results of the assessment in the technical report NEDE-33875P, Revision 3, and are therefore acceptable.

In Item (5) in DCD Tier 2, Sections 3H.6, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the reinforced concrete sliding barriers with structural capacity equivalent to the surrounding wall are provided for the 6 large openings on 1F, as shown in DCD Revision 6, Tier 2, Figure 1.2-8, to limit physical damage to exterior walls. The staff reviewed Figure 1.2-8 in DCD Revision 6, Tier 2 and technical report NEDE-33875P, Revision 3, and finds that reinforced concrete sliding barriers in combination with the external wall are provided to protect the critical penetrations from the impact of a large commercial aircraft, and are therefore acceptable.

The applicant added new Item (12) to the DCD Tier 2, Section 3H.6 which clarifies that the R/B exterior walls on the East, West, and South sides are strengthened with enhanced reinforcement as described in the technical report NEDE-33875P, Revision 3. The staff reviewed the description of the enhanced reinforcement of the exterior wall on the East, West and South of the R/B in Table 4-4 of the technical report NEDE-33875P, Revision 3. The staff finds that the East, West, and South sides are adequately strengthened with enhanced 19.5-14

reinforcement based on the results of the assessment in the technical report NEDE-33875P, Revision 3, and are therefore acceptable.

Based on the above review, the staff finds the applicants description of the location and design of the R/B and RCCV as the key structural design feature for providing protection for maintaining core cooling to be adequate and acceptable, because the applicant described the physical protections and intervening structures to protect the primary containment (RCCV and drywell head) and the entire South wall of the C/B using the guidance of NEI 07-13, Revision 8, as endorsed by RG 1.217, to perform detail structural analyses, and to determine the design of selected structures providing protections in accordance with 10 CFR 50.150(b).

The incorporation of all ABWR DCD Revision 6 Markups provided in Tier 2, Sections 19G.4.2 and 3H.6 is being tracked as a Confirmatory Item 19.5-1.

19.5(D).3.2.4 Location and Design of Service Building Structure The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the capability of the Service Building to protect the east wall of the C/B, and core cooling equipment.

In Item (6) of the DCD Tier 2, Section 19G.4.2, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the location and design of the Service Building structure as described in DCD Tier 2, Section 3H.6 and Figures 1.2-20 through 1.2-22 are key design features that protect the east wall of the C/B from the impact of a large commercial aircraft. The staff reviewed general arrangement drawings in DCD Revision 6, Tier 2, Figure 1.2-1, and Figures 1.2-14 through 1.2-22. The staff also reviewed DCD Revision 6, Tier 1, Section 2.15.14, Service Building, and finds that the Service Building is located adjacent to the C/B. Review of these general arrangement drawings show that the east wall of the C/B is protected by concrete shear wall of Service Building.

The applicant made additional changes in Item (6) to the DCD Tier 2, Section 19G.4.2 that clarify that the Service Building location, fixed with respect to other major structures, is defined in the technical report NEDE-33875P, Revision 3 to ensure that credit of the Service Building as an intervening structure is maintained. The staff reviewed the relevant drawings (DCD Revision 6, Figure 1.2-1 and Figures 1.2-24 through 1.2-22), which show relative relationship of the building locations among the Service Building, C/B, and R/B structures. The staff further reviewed Table 3-2, Intervening Structures Credited in ABWR Aircraft Impact Assessment, and Figure 3-1, ABWR Site Plan - Location of Structures, in the GEH technical report NEDE-33875P, Revision 3, which show the distance from the intervening structures to shielded structure. The applicant screened the Service Building as an intervening structure based on the criteria set in Section 3.2.2 of NEI 07-13, Revision 8, as endorsed by RG 1.217. The staff confirmed that the location of the relevant structures is fixed at the design certification stage.

On these bases, the staff finds credit of the Service Building as an intervening structure acceptable.

The applicant further added new Item (10) to the DCD Tier 2, Section 3H.6 stating that the Service Building exterior wall adjacent to the C/B is a reinforced concrete wall. The applicant described in Table 5-1 of the technical report NEDE-33875P, Revision 3 that this is an input assumption to allow credit of the Service Building wall as an intervening structure. The staff reviewed Figures 1.2-1and 1.2-15 in DCD Tier 2, Revision 6, and Table 5-1 in the technical 19.5-15

report NEDE-33875P, Revision 3, and finds it acceptable, because the applicant screened the Service Building as intervening structure based on the criteria set in Section 3.2.2 of NEI 07-13, Revision 8, as endorsed by RG 1.217.

Based on the above review, the staff finds the applicants description, including location and design, of the Service Building structure as key design features for protecting the east wall of the C/B from the impact of a large, commercial aircraft to be adequate and acceptable, because the applicant adequately described the above design features and functional capabilities in accordance with 10 CFR 50.150(b).

The incorporation of all DCD markups provided in Tier 2, Sections 19G.4.2 and 3H.6 of the revised ABWR DCD Revision 6 Markups, is being tracked as a Confirmatory Item 19.5-1.

19.5(D).3.2.5 Location and Design of Control Building Annex Structure The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the capability of the C/B Annex Building to protect the west wall of the C/B, and core cooling equipment.

In Item (7) of the DCD Tier 2, Section 19G.4.2, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the location and design of the C/B Annex Building structure as described in DCD Tier 2, Section 3H.6 and Figures 1.2-20 through 1.2-22 are key design features that protect the west wall of the C/B from the impact of a large commercial aircraft. The staff reviewed general arrangement drawings in DCD Revision 6, Tier 2, Section 3H.6, Figure 1.2-1, and Figures 1.2-20 through 1.2-22. The staff also reviewed DCD Revision 6, Tier 1, Section 2.15.15, Control Building Annex, and finds that the C/B Annex is located adjacent to the C/B. Review of these general arrangement drawings show that west wall of the C/B is protected by the concrete shear walls of the C/B Annex.

The applicant made additional changes in Item (7) to the DCD Tier 2, Section 19G.4.2 that clarify that the C/B Annex location, fixed with respect to other major structures, is defined in the technical report NEDE-33875P, Revision 3 to ensure that credit of the C/B Annex as an intervening structure is maintained. The staff reviewed the relevant drawings (DCD Revision 6, Figure 1.2-1, and Figures 1.2-24 through 1.2-31), which show the relative relationship of the building locations among the C/B Annex, C/B, and R/B structures. The staff further reviewed Table 3-2 and Figure 3-1 in the GEH technical report NEDE-33875P, Revision 3, which show the distance from the intervening structures to shielded structure. The applicant screened the C/B Annex as an intervening structure based on the criteria set in Section 3.2.2 of NEI 07-13, Revision 8, as endorsed by RG 1.217. The staff confirmed that the location of the relevant structures is fixed at the design certification stage. On these bases, the staff finds credit of the C/B Annex as an intervening structure acceptable.

The applicant made additional changes in item (9) to the DCD Tier 2, Section 3H.6 that state that the C/B Annex Building exterior walls are made of reinforced concrete. The staff reviewed Figures 1.2-1 and 1.2-15 in DCD Tier 2, Revision 6, and Table 5-1 in the technical report NEDE-33875P, Revision 3, and finds it acceptable, because the applicant screened the Service Building as an intervening structure based on the criteria set in Section 3.2.2 of NEI 07-13, Revision 8, as endorsed by RG 1.217.

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Based on the above review, the staff finds the applicants description, including location and design, of the C/B Annex structure as key design features for protecting the west wall of the C/B from the impact of a large, commercial aircraft to be acceptable, because the applicant adequately described the above design features and functional capabilities in accordance with 10 CFR 50.150(b).

The incorporation of all DCD markups provided in Tier 2, Sections 19G.4.2 and 3H.6 of the revised ABWR DCD Revision 6 Markups, is being tracked as a Confirmatory Item 19.5-1.

19.5(D).3.2.6 The Seismic Gap between Reactor Building and Control Building The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the seismic gap between R/B and C/B in protecting the C/B from shock effects from strikes on the R/B.

In Item (8) in DCD Tier 2, Section 19G.4.2 of the revised ABWR DCD Revision 6 Markups, the applicant stated that the seismic gap between the R/B and C/B described in DCD Section 3.8.5 is a key design feature in protecting the C/B from shock effects from strikes on the R/B. The staff reviewed DCD Revision 6, Tier 2, Section 3.8.5.1, and found that both R/B and C/B are supported by the reinforced concrete mat foundations, which are separated from each other by a gap of 2 meters (6 feet - 63/4 inches) to minimize the structural interaction between the buildings. The staff also reviewed Table 3-2 and Figure 3-1 in the GEH technical report NEDE-33875P, Revision 3 (ADAMS Accession No. ML17059C525), which show the distance from the intervening structures to shielded structure. The staff confirmed that the seismic gap between R/B and C/B provided in the report is greater than 2 meters (6 feet - 63/4 inches).

Based on the above review, the staff finds the applicants description, including the seismic gap between the R/B and C/B as a key design features for protecting the C/B from shock effects from strikes on the R/B to be acceptable, because the applicant adequately described the above design features and functional capabilities in accordance with 10 CFR 50.150(b).

19.5(D).3.2.7 Shield Blocks Over Drywell Head The staff reviewed the DCD to ensure that the applicant performed a reasonably formulated assessment of the capability of the shield blocks to protect the integrity of the drywell head from the secondary impact of concrete debris, aircraft wreckage, and falling crane components resulting from the impact of a large commercial aircraft on to the R/B.

In Item (3) in DCD Tier 2, Section 3H.6, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the shield blocks are configured to fully resist secondary impacts from concrete debris, aircraft wreckage and falling crane components to protect the integrity of drywell head. The applicant further stated that the shield blocks are placed over the drywell head in the reactor cavity between the pool girders as shown in DCD Revision 6, Tier 2, Figure 3H.1-23. The staff reviewed DCD Revision 6, Tier 2, Sections 3H.1.3, Description of the Containment and the Reactor Building, Figure 3H.1-23, Section 3H.6, and GEH technical report NEDE-33875P, Revision 3. As described in the DCD sections and in the technical report, the shield blocks are configured to fully resist secondary impacts from concrete debris, aircraft wreckage and falling crane components to protect the integrity of drywell head.

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Based on the above review, the staff finds the applicants description of the shield blocks as the key structural design feature for providing physical protection of the integrity of the drywell head to be acceptable, because the applicant adequately described the above design features and functional capabilities in accordance with 10 CFR 50.150(b).

19.5(D).4 Shock Damage DCD Tier 2, Section 19G.2 states that the analysis of aircraft impacts considers the effects of shock-induced vibrations on SSCs. In DCD Tier 2, Section 19G.4.1, Revision 6, Primary Containment, the applicant stated that safety-related components inside primary containment, including the reactor pressure vessel and associated ECCS piping are not adversely affected by shock-induced vibrations resulting from the impact of a large commercial aircraft. In addition, DCD Tier 2, Section 19G.4.4 states that all support systems were assessed for shock damage.

Based on the applicants use of the NRC RG 1.217, NRC endorsed guidance from NEI 07-13, Revision 8, and an assessment scope that includes shock-induced vibration, the staff finds that the applicant has performed a reasonably formulated shock analysis within the aircraft impact assessment.

19.5(D).5 Spent Fuel Pool Integrity In DCD Tier 2, Section 19G.2, Scope of Assessment, of the revised ABWR DCD Revision 6 Markups, the applicant stated that the SFP and RCCV are not perforated, based on the assessment results, in the case of an aircraft impact; therefore, assessment of the damage to RCCV internal SSCs and secondary impact is not required. In Item (4), in Section 19G.4.2 in DCD Tier 2, of the revised ABWR DCD Revision 6 Markups, the applicant stated the location and design, and its supporting structures as described in DCD Tier 2, Section 9.1 and Figure 1.2-12 are the key design features in protecting the SFP from the impact of a large commercial aircraft. However, the applicant did not describe whether an assessment was performed to ensure that required minimum water level in the SFP is maintained in the case of an aircraft impact. Therefore, on April 20, 2015, the staff issued RAI 19-6 (ADAMS Accession No. ML15110A122), requesting the applicant confirm if an assessment was performed to ensure there is no leakage through the SFP liner below the required minimum water level of the pool.

The applicant responded in a letter dated September 17, 2015 (ADAMS Accession No. ML15264A003), and submitted clarification in the DCD Tier 2, Section 19G.5, Conclusions of Assessment, that the aircraft impact would not inhibit the ABWRs core cooling capacity and SFP integrity based on the best estimate calculations. Previously, as part of the DCD Revision 6, the applicant stated that [t]here are no AIA scenarios that would result in leakage from the SFP below the required minimum water level. The location and design of the SFP and its supporting structure preclude a direct hit from aircraft impact, therefore the pool liner is not perforated and all piping attachments are configured such that they would not allow drain down below the minimum water level described in DCD Section 9.1.3.3. The staff assessed the response and finds that the applicant adequately addressed this question since the aircraft impact would not inhibit the ABWRs core cooling capability and spent SFP pool integrity based on best estimate calculations performed in accordance with NEI 07-13, Revision 8, as endorsed by RG 1.217. Therefore, the staff considers RAI 19-6 to be resolved and closed.

The applicant made additional changes in Item (1) to the DCD Tier 2, Section 3H.6, of the revised ABWR DCD Revision 6 Markups. The applicant stated that (1) the structural configuration of SFP within the R/B precludes a direct strike on the SFP; (2) the spent-fuel pool 19.5-18

is a reinforced concrete structure with a specified minimum thick ASTM A-240 Type 304L stainless steel liner; (3) the SFP walls are strengthened as described in the technical report NEDE-33875P, Revision 3, to ensure the integrity of the SFP is maintained. The staff reviewed DCD Revision 6, Tier 2, Sections 9.1.2, Spent-Fuel Storage, and the technical report, and the staff confirmed that the SFP is a reinforced structure with a specified minimum thick stainless steel liner and the SFP walls are strengthened.

Based on the above review, the staff finds that the description of the key design features for ensuring SFP integrity to be acceptable, because the applicant adequately described the above design features and functional capabilities in accordance with 10 CFR 50.150(b).

19.5(E) Conclusion The staff finds that the applicant has performed an AIA that is reasonably formulated to identify design features and functional capabilities that show, with reduced use of operator action, that the acceptance criteria in 10 CFR 52.59(a) and the acceptance criteria in 10 CFR 50.150(a)(1) are met.

The staff also finds that the applicant adequately described the key design features and functional capabilities identified and credited to meet 10 CFR 50.150(b), including descriptions of how the key design features meet the acceptance criteria in 10 CFR 50.150(a)(1), namely that the facility can withstand the effects of a large commercial aircraft impact such that the reactor core remains cooled and SFP integrity is maintained. Therefore, the staff finds that the applicant meets the applicable requirements of 10 CFR 50.150(b). Inclusion of the proposed changes in Revision 6 Markups of the DCD are being tracked by the Confirmatory Item 19.5-1 as discussed above.

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