ML18120A345

Safety Evaluation - Vogtle Electric Generating Plant Units 3 and 4 LAR 18-002

ML18120A345
Person / Time
Site:	Vogtle
Issue date:	06/15/2018
From:	Jordan Hoellman NRC/NRO/DNRL/LB4
To:	Southern Nuclear Operating Co
hoellman j/415-5481
References
EPID L-2018-LLA-0025, LAR 18-002
Download: ML18120A345 (10)

Text

SAFETY EVALUATION BY THE OFFICE OF NEW REACTORS RELATED TO AMENDMENT NOS. 127 AND 126 TO THE COMBINED LICENSE NOS. NPF-91 AND NPF-92, RESPECTIVELY SOUTHERN NUCLEAR OPERATING COMPANY, INC.

GEORGIA POWER COMPANY OGLETHORPE POWER CORPORATION MEAG POWER SPVM, LLC MEAG POWER SPVJ, LLC MEAG POWER SPVP, LLC CITY OF DALTON, GEORGIA VOGTLE ELECTRIC GENERATING PLANT UNITS 3 AND 4 DOCKET NOS.52-025 AND 52-026

1.0 INTRODUCTION

By letter dated February 1, 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18032A359), Southern Nuclear Operating Company (SNC) submitted license amendment request (LAR)18-002 requesting U.S. Nuclear Regulatory Commission (NRC or the Commission) approval for amendments to Combined License (COL)

Nos. NPF-91 and NPF-92 for the Vogtle Electric Generating Plant (VEGP), Units 3 and 4, respectively, regarding changes to the building gap between the Nuclear Island (NI) and adjacent buildings.

The requested amendment (LAR 18-002) would revise the Updated Final Safety Analysis Report (UFSAR) in the form of departures from the incorporated plant-specific Design Control Document (DCD) Tier 2* and Tier 2 information and involves related changes to plant-specific Tier 1 information, with corresponding changes to the associated COL Appendix C information.

Specifically, the requested amendment proposes changes to relax the minimum gap requirement above grade between the NI and the annex building/turbine building and to remove the minimum gap requirement between the NI and the radwaste building from the Inspections, Tests, Analyses and Acceptance Criteria (ITAAC) and corresponding Tier 1 information.

Pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 52.63(b)(1), SNC also requested an exemption from the provisions of 10 CFR Part 52, Appendix D, Design

Certification Rule for the AP1000 Design,Section III.B, Scope and Contents. This exemption request will allow a departure from the corresponding portions of the certified information in Tier 1 of the generic DCD.1 In order to grant SNCs request to modify the UFSAR (the plant-specific DCD) Tier 1 information, the NRC must be able to determine that the exemption will comply with the requirements of 10 CFR 52.7 and 50.12. In addition to the factors listed in 10 CFR 50.12, the Commission shall consider whether the special circumstances that Section 50.12 requires to be present outweigh any decrease in safety that may result from the reduction in standardization caused by the exemption. The Commission shall also consider whether the design change will result in a significant decrease in the level of safety otherwise provided by the design. The staffs review of the exemption request, as well as the LAR, is included in this safety evaluation.

On February 27, 2018, the NRC staff published a proposed no significant hazards consideration determination in the Federal Register (83 FR 8519) for the proposed amendment.

2.0 REGULATORY EVALUATION

LAR 18-002 proposes to change the minimum gap requirement above grade (grade is defined in licensing bases as EL 100) between the NI and the annex building/turbine building from 4 gap to 3 gap and to delete the gap requirement between the NI and the radwaste building from COL Appendix C Subsection 3.3 and ITAAC No. 3.3.00.13. Also, the proposed changes delete minimum from the gap requirement for the radwaste building in UFSAR Subsection 3.7.2.8.2 to allow SNC to account[] for the construction tolerances defined in American Concrete Institute (ACI) 117 and American Institute of Steel Construction (AISC) 303. Tier 1 Information is defined in 10 CFR Part 52, Appendix D Section II.D.

The NRC staff considered the following regulatory requirements in reviewing the LAR that included the proposed UFSAR changes.

10 CFR Part 52, Appendix D, Section VIII.A.4, states that exemptions from Tier 1 information are governed by 10 CFR 52.63(b)(1) and 52.98(f). It also states that the Commission will deny a request for an exemption from Tier 1, if it finds that the design change will result in a significant decrease in the level of safety otherwise provided by the design.

10 CFR Part 52, Appendix D, Section VIII.B.5.a allows an applicant or licensee who references this appendix to depart from Tier 2 information, without prior NRC approval, unless the proposed departure involves a change to or departure from Tier 1 information, Tier 2*

information, or the Technical Specifications, or requires a license amendment under paragraphs B.5.b or B.5.c of the section.

10 CFR 52.63(b)(1) allows the licensee who references a design certification rule to request NRC approval for an exemption from one or more elements of the certification information. The Commission may only grant such a request if it determines that the exemption will comply with 1

While SNC describes the requested exemption as being from Section III.B of 10 CFR Part 52, Appendix D, the entirety of the exemption pertains to proposed departures from Tier 1 information in the generic DCD. In the remainder of this evaluation, the NRC will refer to the exemption as an exemption from Tier 1 information to match the language of Section VIII.A.4 of 10 CFR Part 52, Appendix D, which specifically governs the granting of exemptions from Tier 1 information.

the requirements of 10 CFR 52.7, which, in turn, points to the requirements listed in 10 CFR 50.12 for specific exemptions. In addition to the factors listed in 10 CFR 52.7, the Commission shall consider whether the special circumstances present outweigh any decrease in safety that may result from the reduction in standardization caused by the exemption.

Therefore, any exemption from the Tier 1 information certified by Appendix D to 10 CFR Part 52 must meet the requirements of 10 CFR 50.12, 52.7, and 52.63(b)(1).

10 CFR 52.97(b) requires the ITAAC in a COL to be necessary and sufficient to provide reasonable assurance that, if the ITAAC are satisfied, the facility has been constructed and will be operated in conformity with the license, the provisions of the Atomic Energy Act of 1954, as amended, and the Commission's rules and regulations.

10 CFR 52.98(f) requires NRC approval for any modification to, addition to, or deletion from the terms and conditions of a COL. These activities involve a change to COL Appendix C ITAAC information with corresponding changes to the associated plant-specific DCD Tier 1 information.

Therefore, NRC approval is required prior to making the plant-specific proposed changes in this LAR.

10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, Appendix A, General Design Criteria for Nuclear Power Plants, General Design Criterion (GDC) 1, Quality standards and records, provides, in part, that structures, systems, and components (SSCs) important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of safety functions to be performed.

GDC 2, Design bases for protection against natural phenomena, provides, in part, that SSCs important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions.

GDC 4, Environmental and dynamic effects design bases, provides, in part, that SSCs important to safety shall be designed to accommodate the effects of and to be compatible with the environmental conditions associated with normal operation, maintenance, testing, and postulated accidents, including loss-of-cooling accidents.

3.1 TECHNICAL EVALUATION

OF PROPOSED CHANGES The staff evaluated the impact of changing the minimum gap requirement above grade between the NI and the annex building/turbine building from 4 gap to 3 gap and deleting the gap requirement between the NI and the radwaste building from COL Appendix C, Subsection 3.3 and ITAAC No. 3.3.00.13. The proposed changes delete minimum from the gap requirement for the radwaste building in UFSAR Subsection 3.7.2.8.2 to allow SNC to accounting for the construction tolerances defined in American Concrete Institute (ACI) 117 and American Institute of Steel Construction (AISC) 303. In performing their evaluation, the staff considered SNCs design criteria described in UFSAR Subsection 3.7.2, Seismic Analysis, for the annex building where the portion of the annex building adjacent to the NI is classified as a seismic Category II building. The seismic Category II building structures are designed for the safe shutdown earthquake (SSE) using the same methodology and design criteria as are used for seismic Category I structures. The radwaste building is classified as non-seismic and is designed to the seismic requirements of the Uniform Building Code, Zone 2A with an importance Factor of 1.25.

Also, for the LAR review, the staff considered Standard Review Plan (SRP) Section 3.8.5, Foundation, and SRP Section 3.7.2, Seismic System Analysis, which provide an acceptable method for meeting the requirements of GDC 1, 2, and 4, for guidance on the acceptance of the structure design. SNC categorized two changes:

1) Gap between the NI and annex building/turbine building

2) Gap between the NI and the radwaste building.

In change number 1, SNC proposed to change the minimum gap requirement above grade between the NI and annex building/turbine building from 4 to 3. Currently, the requirement in the licensing bases for the minimum seismic gap between the NI and annex/turbine buildings is 4 inches above grade, as specified in COL Appendix C, ITAAC No. 3.3.00.13, UFSAR Appendix 2.5E Section 5.2, and UFSAR Subsections 3.7.2.8.1 and 3.8.5.1. The purpose of the gap is to avoid contact between the NI and seismic Category II structures (annex building/turbine building) during a seismic event. In the current licensing bases, the seismic response analyses, including soil-structure interaction between NI and the adjacent buildings, are performed using the System for Analysis of Soil-Structure Interaction (SASSI) program. As specified in UFSAR Subsection 3.7.2.8.4, the relative displacement between the NI and adjacent buildings is established from the SASSI 2D analysis. SNC stated that previous design changes are incorporated into the latest AP1000 generic 2D SASSI analysis, including changes to the NI (e.g., polar crane mass change) and adjacent buildings (e.g., change of structures of turbine building first bay). The latest AP1000 generic 2D SASSI analysis shows that the maximum relative seismic displacement between the annex building and the NI is 0.95 inches, and between the turbine building and the NI is 1.04 inches. Both relative displacements are less than the proposed 2 inch maximum seismic relative displacement. A site specific 2D SASSI analysis was performed for VEGP Units 3 and 4 to show the acceptability of the AP1000 plant at the VEGP site. Also, SNC stated that a study has been performed to compare the deflection at the perimeter walls from the generic SASSI analysis using models including the significant building changes to those that do not include the changes. The staff accepts SNCs study because it was based on the approved design bases methodology and the study confirmed that the recent changes do not have significant impact on the result of the relative displacement between buildings.

The staff reviewed SNCs settlement evaluation in LAR 18-002. The staff also considered SNCs information described in UFSAR Subsection 2.5.4.10.2, Settlement Analysis, for acceptable settlement and differential settlement limits and settlement monitoring plan throughout the entire construction sequence. The purpose of the staffs review is to determine if the differential settlement between the NI foundation and the foundations of the annex/turbine buildings will impose any adverse effect on the gaps between the NI and the annex/turbine buildings.

In its LAR, SNC stated that differential settlement of foundations may impact the gaps between the NI and adjacent buildings. Based on the evaluation of the VEGP Units 3 and 4 settlement survey data, collected from the settlement monitoring program for the past few years during all construction stages, SNC indicated that the walls of the NI and adjacent buildings will not tend to lean towards the gap. Therefore, SNC predicted that differential settlement does not have an adverse impact on the gaps between the NI and adjacent buildings.

The staff agrees that the required gap between the NI and the annex/turbine buildings can be maintained if the differential settlement of foundations will not cause the walls to tilt towards the gap. In order to verify the basis for SNCs conclusion, the staff conducted an audit on April 5, 2018 (ADAMS Accession No. ML18113A105), to review VEGP Unit 3 and 4 settlement survey data and related documentation.

During the audit, the staff reviewed the VEGP Unit 3 and 4 settlement survey data and related documentation. The staff noted that the reviewed documents contain the settlement survey data and plots of VEGP Unit 3 and 4 for the past few years through different construction stages. The plots, based on the survey data, present the settlement profile in the east-west direction and north-south direction for the foundations of the NI and the turbine building and the annex building. As mentioned previously, the survey data represents the beginning of the construction stage to the current stage. The staff further noted that measured actual settlements are at least 40 percent less than the calculated settlements using the analytical model. This indicates that the subsurface material properties under the foundations were conservatively assumed in analytical analysis. Based on this observation, the staff reasonably expects that settlement will be well controlled within the settlement limits throughout the entire construction sequence and through the long-term (plant operation).

The staff confirmed through its examination of the settlement survey data and plots that 1) the NI basemat has deflected more in the center and less at the perimeter, which would tend to cause the perimeter walls to lean towards the center of the nuclear building; 2) the foundation deflection contour of the turbine building is similar to that of the NI, which would tend to cause the turbine building first bay structures to lean away from the NI; and 3) the foundation deflection of the annex building is very uniform along the east-west direction and has a center-dipped trend along the north-south direction, which does not result in tilt of the perimeter structures to the west (NI direction). Based on above, the staff finds that the differential settlement of foundations will not impose any adverse effect on the gaps between the NI and the annex/turbine buildings.

In change number 2, SNC proposed deleting the gap requirement between the NI and radwaste building, in Tier 1, Subsection 3.3 and Table 3.3-6, Inspections, Test and Analyses, and revising UFSAR Subsection 3.7.2.8.2, Radwaste Building, by deleting minimum and changing clearance to gap in the last sentence of the first paragraph. In addition to the changes, SNC proposed changes to UFSAR Subsection 3.8.5.1, Description of Foundation, by adding the sentence, The radwaste building is separated from the nuclear island by a 2-inch gap at and below grade and a 4-inch gap above grade. before the last sentence of the paragraph. In UFSAR Subsection 3.7.2.8, non-seismic structures are evaluated to demonstrate that their seismic response does not impair the safety function of seismic Category I SSCs by satisfying one of the following requirements:

• The collapse of the non-seismic structure will not cause the non-seismic structure to strike a seismic Category I SSC.

• The collapse of the non-seismic structure will not impair the integrity of seismic Category I SSC.

• The structure is classified as seismic Category II and is analyzed and designed to prevent its collapse under the SSE.

SNC stated that the radwaste building is evaluated based on the assumption that it collapses and strikes the auxiliary building during an SSE event by using three methods in UFSAR Subsection 3.7.2.8.2. The auxiliary building is part of the NI. The impact evaluation performed by SNC demonstrated that the radwaste building impact on the NI during an SSE event will not impair its structural integrity, and meets the second bullet requirement as stated above. Further, SNC stated that the kinetic energy for the impact evaluation is calculated based on the velocity and mass of the radwaste building and the auxiliary building. The evaluation demonstrates that when the radwaste building strikes the auxiliary building during SSE event, the kinetic energy generated by the radwaste building strike is less than the kinetic energy generated by the automobile tornado missile. The gap between the radwaste building and NI is not an input to the impact evaluation, and therefore does not affect the ability to meet the licensing basis requirement for the NI to remain integral under the radwaste building impact during SSE event.

Also, SNC clarified and revised UFSAR Subsection 3.8.5.1 to specify the requirements for seismic Category II structures and non-seismic structures separately. This proposed change is consistent with the licensing bases requirements and is consistent with the proposed changes in COL Appendix C Subsection 3.3 and ITAAC No. 3.3.00.13, and UFSAR Subsections 3.7.2.8.1 and 3.7.2.8.2.

With respect to the change to COL Appendix C ITAAC No. 3.3.00.13 to remove the requirement to verify separation between the radwaste building and the NI, the staff finds, for the reasons given above, that this verification is unnecessary. The other changes to the ITAAC align with the changes to the design, so that the ITAAC verifies construction in accordance with the design. Therefore, the proposed changes to the ITAAC comply with 10 CFR 52.97(b).

Based on the above, the staff finds that the proposed changes to the gap requirements between the structures do not affect the structural integrity requirements on seismic Category I structures. The performance of the seismic Category II structures are not impacted. The design of the structures is consistent with the acceptance criteria specified in the SRP Subsections 3.7.2.8 and 3.8.5, and the UFSAR. Therefore, based on the reasons specified above, the staff finds that the proposed amendment meets relevant design provisions. Based on these findings and because the LAR meets the guidance in SRP Sections 3.7.2 and 3.8.5, the staff concludes that there is reasonable assurance that the requirements of GDC 1, 2, and 4 of Appendix A to 10 CFR Part 50 will continue to be met. Therefore, the staff finds the proposed changes to be acceptable.

3.2 EVALUATION OF EXEMPTION The regulations in Section III.B of Appendix D to 10 CFR Part 52 require a holder of a COL referencing Appendix D to 10 CFR Part 52 to incorporate by reference and comply with the requirements of Appendix D, including certified information in Tier 1 of the generic AP1000 DCD. Exemptions from Tier 1 information are governed by the change process in Section VIII.A.4 of Appendix D of 10 CFR Part 52. Because SNC has identified changes to plant-specific Tier 1 information, with corresponding changes to the associated COL Appendix C information resulting in the need for a departure, an exemption from the certified design information within plant-specific Tier 1 material is required to implement the LAR.

The Tier 1 information for which a plant-specific departure and exemption was requested relates to changing the gap requirements between the NI and the annex building/turbine building and removing the minimum gap requirement between the NI and the radwaste building from the ITAAC. The result of this exemption would be that SNC could implement the requested modifications to Tier 1 information, with corresponding changes to COL Appendix C. Pursuant to the provisions of 10 CFR 52.63(b)(1), an exemption from elements of the design as certified in the 10 CFR Part 52, Appendix D, design certification rule is requested for the involved Tier 1 information described and justified in LAR 18-002. This exemption is a permanent exemption limited in scope to the particular Tier 1 information specified.

As stated in Section VIII.A.4 of Appendix D to 10 CFR Part 52, an exemption from Tier 1 information is governed by the requirements of 10 CFR 52.63(b)(1) and 52.98(f). Additionally,Section VIII.A.4 of Appendix D to 10 CFR Part 52 provides that the Commission will deny a request for an exemption from Tier 1 if it finds that the requested change will result in a significant decrease in the level of safety otherwise provided by the design. Pursuant to 10 CFR 52.63(b)(1), the Commission may grant exemptions from one or more elements of the certification information, so long as the criteria given in 10 CFR 52.7, which, in turn, references 10 CFR 50.12, are met and that the special circumstances, which are defined by 10 CFR 50.12(a)(2), outweigh any potential decrease in safety due to reduced standardization.

Pursuant to 10 CFR 52.7, the Commission may, upon application by any interested person or upon its own initiative, grant exemptions from the requirements of 10 CFR Part 52. As 10 CFR 52.7 further states, the Commissions consideration will be governed by 10 CFR 50.12, Specific exemptions, which states that an exemption may be granted when: (1) the exemptions are authorized by law, will not present an undue risk to the public health and safety, and are consistent with the common defense and security; and (2) special circumstances are present. Specifically, 10 CFR 50.12(a)(2) lists six circumstances for which an exemption may be granted. It is necessary for one of these bases to be present in order for the NRC to consider granting an exemption request. SNC stated that the requested exemption meets the special circumstances of 10 CFR 50.12(a)(2)(ii). That subparagraph defines special circumstances as when [a]pplication of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule. The staffs analysis of these findings is presented below.

3.2.1 AUTHORIZED BY LAW The requested exemption would allow SNC to implement a revision to Tier 1, Subsection 3.3 and Table 3.3-6 in the plant-specific DCD. This exemption is a permanent exemption limited in scope to particular Tier 1 information. Subsequent changes to Tier 1, Subsection 3.3 and Table 3.3-6 or any other Tier 1 information would be subject to the exemption process specified in Section VIII.A.4 of Appendix D to 10 CFR Part 52 and the requirements of 10 CFR 52.63(b)(1).

As stated above, 10 CFR Part 52, Appendix D, Section VIII.A.4 allows the NRC to grant exemptions from one or more elements of the Tier 1 information. The NRC staff has determined that granting of SNCs proposed exemption will not result in a violation of the Atomic Energy Act of 1954, as amended, or the Commissions regulations. Therefore, as required by 10 CFR 52.7 and 10 CFR 50.12(a)(1), the exemption is authorized by law.

3.2.2 NO UNDUE RISK TO PUBLIC HEALTH AND SAFETY As discussed above in the technical evaluation, the proposed changes comply with the NRCs substantive safety regulations. Therefore, there is no undue risk to the public health and safety.

3.2.3 CONSISTENT WITH COMMON DEFENSE AND SECURITY The proposed exemption would allow a change in the gap requirements between the NI and the annex building/turbine building and remove the minimum gap requirement between the NI and radwaste building from the ITAAC, as presented in plant-specific Tier 1 information, thereby departing from the AP1000 certified (Tier 1) design information. The change does not alter or impede the design, function, or operation of any plant structures, systems, or components associated with the facilitys physical or cyber security and, therefore, does not affect any plant equipment that is necessary to maintain a safe and secure plant status. In addition, the changes have no impact on plant security or safeguards. Therefore, as required by 10 CFR 52.7 and 10 CFR 50.12(a)(1), the staff finds that the common defense and security is not impacted by this exemption.

3.2.4 SPECIAL CIRCUMSTANCES Special circumstances, in accordance with 10 CFR 50.12(a)(2), are present, in part, whenever application of the regulation in the particular circumstances would not serve the underlying purpose of the rule or is not necessary to achieve the underlying purpose of the rule. The underlying purpose of the Tier 1 information is to ensure that a licensee will safely construct and operate the plant based on the certified information found in the AP1000 DCD, which was incorporated by reference into the VEGP Units 3 and 4 licensing basis. The proposed changes described in the above technical evaluation do not impact the ability of any SSCs to perform their functions or negatively impact safety.

Special circumstances are present in the particular circumstances discussed in LAR 18-002 because the application of the specified Tier 1 information is not necessary to achieve the underlying purpose of the rule. The proposed exemption implements changes to the gap requirements between the NI and adjacent buildings. This exemption requests revisions to Tier 1, Subsection 3.3 and Table 3.3-6 that continue to demonstrate that the applicable regulatory requirements will be met. Therefore, for the above reasons, the staff finds that the special circumstances required by 10 CFR 52.7 and 10 CFR 50.12(a)(2)(ii) for the granting of an exemption from the Tier 1 information exist.

3.2.5 SPECIAL CIRCUMSTANCES OUTWEIGH REDUCED STANDARDIZATION This exemption would allow the implementation of changes to Tier 1, Subsection 3.3 and Table 3.3-6 in the plant-specific DCD. The justification provided in LAR 18-002, the exemption request, and the associated licensing basis mark-ups demonstrate that there is a limited change from the standard information provided in the generic AP1000 DCD. The design functions of the system associated with this request will continue to be maintained because the associated revisions to Subsection 3.3 and Table 3.3-6 demonstrate that the applicable regulatory requirements will continue to be met. The proposed exemption would allow changes in the gap requirements between the NI and the annex building/turbine building and remove the minimum gap requirement between the NI and radwaste building from the ITAAC, as presented in plant-specific Tier 1 information. The staff has determined that there is no decrease in safety resulting from a reduction in standardization because: (1) with respect to the radwaste building, maintaining a minimum clearance is not necessary for safety, (2) with respect to the turbine and annex buildings, the existing requirement is not precise, in that it requires only a minimum clearance and doesnt specify a maximum, and the changes proposed for the minimum clearance is minor, and (3) the changes pertain to one-time construction of specific buildings at a particular site. Therefore, a reduction in standardization is not expected to have any safety impact. Based on the foregoing reasons, as required by 10 CFR Part 52.63(b)(1), the staff finds that the special circumstances outweigh any decrease in safety that may result from the reduction of standardization of the AP1000 design.

3.2.6 NO SIGNIFICANT REDUCTION IN SAFETY This exemption would allow the implementation of changes discussed above. The exemption request proposes to depart from the certified design by allowing changes discussed above in the technical evaluation. The proposed changes will not adversely affect the ability of any systems or equipment from performing their design function, and no new failure modes are introduced. Therefore, based on the foregoing reasons and as required by 10 CFR 52.7, 10 CFR 52.98(f), and 10 CFR Part 52, Appendix D, Section VIII.A.4, the staff finds that granting the exemption would not result in a significant decrease in the level of safety otherwise provided by the design.

3.3

SUMMARY

Based on the technical evaluations above, the staff finds that the proposed changes to building gaps are acceptable.

4.0 STATE CONSULTATION

In accordance with the Commission's regulations in 10 CFR 50.91(b)(2), on April 27, 2018, the Georgia State official was consulted regarding the amendment. The State official had no comments.

5.0 ENVIRONMENTAL CONSIDERATION

The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20, Standards for Protection Against Radiation. The staff has determined that the amendment involves no significant increase in the amounts, and no significant change in the types, of any effluents that may be released offsite. Also, there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a proposed finding that the amendment involves no significant hazards consideration, and there has been no public comment on such finding (Federal Register, 83 FR 8519, dated February 27, 2018).

Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Under 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.

Because the exemption is necessary to allow the changes proposed in this LAR, and because the exemption does not authorize any activities other than those proposed in this LAR, the environmental consideration for the exemption is identical to that of the license amendment.

Accordingly, the exemption meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), the staff finds that no environmental impact statement or environmental assessment needs to be prepared in connection with the issuance of the exemption.

6.0 CONCLUSION

The staff has determined that pursuant to Section VIII.A.4 of Appendix D to 10 CFR Part 52, the exemption proposed in this LAR (1) is authorized by law; (2) presents no undue risk to the public health and safety; (3) is consistent with the common defense and security; (4) presents special circumstances; (5) justifies that the special circumstances outweigh the potential decrease in safety due to reduced standardization; and (6) does not result in a significant decrease in the level of safety otherwise provided by the design. Therefore, the NRC staff grants the exemption from the Tier 1 information requested by SNC.

The staff has also concluded, based on the technical evaluation presented in Section 3.2 above regarding the changes to the building gap requirements between the NI and adjacent buildings that there is reasonable assurance that: (1) the health and safety of the public will not be endangered by construction and operation in the proposed manner; (2) there is reasonable assurance that such activities will be conducted in compliance with the Commissions regulations; and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public. Therefore, the NRC staff finds the changes proposed in this LAR acceptable.

7.0 REFERENCES

1. Request for License Amendment and Exemption RE: Changes to the Gap between the Nuclear Island and Adjacent Building (LAR 18-002) letter from Southern Nuclear Operating Company, dated February 1, 2018 (ADAMS Accession No. ML18032A359).

2. Vogtle Electric Generating Plant, Units 3 and 4 Updated Final Safety Analysis Report, Revision 6 and Tier 1, Revision 5, dated June 15, 2017 (ADAMS Accession No. ML17172A218).

3. Audit Plan for Vogtle Electric Generating Plant (LAR 18-002) RE: Changes to the Building Gap between the Nuclear Island and Adjacent Buildings, dated April 3, 2018 (ADAMS Accession No. ML18089A282).

4. Audit Summary for Vogtle Electric Generating Plant (LAR 18-002) RE: Changes to the Building Gap between the Nuclear Island and Adjacent Buildings, dated April 24, 2018 (ADAMS Accession No. ML18113A105).

5. AP1000 Design Control Document, Revision 19, dated June 13, 2011 (ADAMS Accession No. ML11171A500).

6. SRP Section 3.7.2, Seismic System Analysis (ADAMS Accession No. ML100630323).

7. SRP Section 3.8.5, Foundations (ADAMS Accession No. ML100630323).