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| issue date = 07/25/2018
| issue date = 07/25/2018
| title = Staff Review of Spent Fuel Pool Evaluation Associated with Reevaluated Seismic Hazard Implementation Near- Task Force Recommendation 2.1: Seismic
| title = Staff Review of Spent Fuel Pool Evaluation Associated with Reevaluated Seismic Hazard Implementation Near- Task Force Recommendation 2.1: Seismic
| author name = Vega F G
| author name = Vega F
| author affiliation = NRC/NRR/DLP/PBMB
| author affiliation = NRC/NRR/DLP/PBMB
| addressee name = Burchfield E
| addressee name = Burchfield E
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=Text=
=Text=
{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 Mr. Ed Burchfield, Jr. Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752 July 25, 2018
{{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 25, 2018 Mr. Ed Burchfield, Jr.
Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752


==SUBJECT:==
==SUBJECT:==
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3-STAFF REVIEW OF SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID L-2017-JLD-0056)  
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3- STAFF REVIEW OF SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID L-2017-JLD-0056)


==Dear Mr. Burchfield:==
==Dear Mr. Burchfield:==


The purpose of this letter is to inform Duke Energy Carolinas, LLC (Duke, the licensee), of the results of the U.S. Nuclear Regulatory Commission (NRC) staff's review of the spent fuel pool (SFP) evaluation for Oconee Nuclear Station, Units 1, 2, and 3 (Oconee), which was submitted in response to Item (9) of Enclosure 1 of the NRC's March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12053A340), request for information issued under Title 10 of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The NRC staff concludes that the licensee's assessment was performed consistent with the NRG-endorsed SFP Evaluation Guidance Report and that the licensee has provided sufficient information to complete the response to Item (9) of the 50.54(f) letter. BACKGROUND On March 12, 2012, the NRC issued the 50.54(f) letter as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate seismic hazards at their sites using present-day methodologies and guidance.
The purpose of this letter is to inform Duke Energy Carolinas, LLC (Duke, the licensee), of the results of the U.S. Nuclear Regulatory Commission (NRC) staff's review of the spent fuel pool (SFP) evaluation for Oconee Nuclear Station, Units 1, 2, and 3 (Oconee), which was submitted in response to Item (9) of Enclosure 1 of the NRC's March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), request for information issued under Title 10 of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The NRC staff concludes that the licensee's assessment was performed consistent with the NRG-endorsed SFP Evaluation Guidance Report and that the licensee has provided sufficient information to complete the response to Item (9) of the 50.54(f) letter.
Enclosure 1, Item (4), of the 50.54(f) letter requested that licensees perform a comparison of the ground motion response spectrum (GMRS) and the safe shutdown earthquake (SSE). The staff's assessment of the information provided in response to Items (1 )-(3) and (5)-(7) and the comparison portion of Item (4) of the 50.54(f) letter was provided by letter dated July 22, 2015 (ADAMS Accession No. ML 15201A008).
BACKGROUND On March 12, 2012, the NRC issued the 50.54(f) letter as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate seismic hazards at their sites using present-day methodologies and guidance. Enclosure 1, Item (4), of the 50.54(f) letter requested that licensees perform a comparison of the ground motion response spectrum (GMRS) and the safe shutdown earthquake (SSE). The staff's assessment of the information provided in response to Items (1 )-(3) and (5)-(7) and the comparison portion of Item (4) of the 50.54(f) letter was provided by letter dated July 22, 2015 (ADAMS Accession No. ML15201A008). Enclosure 1, Item (9), of the 50.54(f) letter requested that, when the GMRS exceeds the SSE in the 1 to 10 Hertz frequency range, the licensee provide a seismic evaluation of the SFP. More specifically, licensees were asked to consider " ... all seismically induced failures that can lead to draining of the SFP."
Enclosure 1, Item (9), of the 50.54(f) letter requested that, when the GMRS exceeds the SSE in the 1 to 10 Hertz frequency range, the licensee provide a seismic evaluation of the SFP. More specifically, licensees were asked to consider " ... all seismically induced failures that can lead to draining of the SFP."
 
E. Burchfield By letter dated January 31, 2017 (ADAMS Accession No. ML 17031A171), the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) Report No. 3002009564 entitled, "Seismic Evaluation Guidance:
E. Burchfield                                     By letter dated January 31, 2017 (ADAMS Accession No. ML17031A171), the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) Report No. 3002009564 entitled, "Seismic Evaluation Guidance: Spent Fuel Pool Integrity Evaluation" (SFP Evaluation Guidance Report). The SFP Evaluation Guidance Report provides criteria for evaluating the seismic adequacy of an SFP to the reevaluated GMRS hazard levels. This report supplements the guidance in EPRI Report 1025287, "Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID)" (ADAMS Accession No. ML12333A170). The NRC endorsed the SFP Evaluation Guidance Report by letter dated February 28, 2017 (ADAMS Accession No. ML17034A408), as an acceptable method for licensees to use when responding to Item (9) in Enclosure 1 of the 50.54(f) letter.
Spent Fuel Pool Integrity Evaluation" (SFP Evaluation Guidance Report). The SFP Evaluation Guidance Report provides criteria for evaluating the seismic adequacy of an SFP to the reevaluated GMRS hazard levels. This report supplements the guidance in EPRI Report 1025287, "Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID)" (ADAMS Accession No. ML 12333A 170). The NRC endorsed the SFP Evaluation Guidance Report by letter dated February 28, 2017 (ADAMS Accession No. ML 17034A408), as an acceptable method for licensees to use when responding to Item (9) in Enclosure 1 of the 50.54(f) letter. By letter dated October 27, 2015 (ADAMS Accession No. ML 15194A015), the NRC staff stated that SFP evaluation submittals for sites with GMRS peak spectral accelerations above 0.8g were expected by December 31, 2017. By letter dated July 11, 2017 (ADAMS Accession No. ML 17192A 168), the NRC issued a generic audit plan and entered into the audit process described in Office Instruction LIC-111, "Regulatory Audits," dated December 29, 2008 (ADAMS Accession No. ML082900195), to assist in the timely and efficient closure of activities associated with the 50.54(f) letter at Oconee. The staff used the audit process as described below during the SFP evaluation review. REVIEW OF LICENSEE SPENT FUEL POOL EVALUATION By letter dated December 4, 2017 (ADAMS Accession No. ML 17348A075), the licensee submitted its SFP evaluation for Oconee. The NRC staff assessed the licensee's implementation of the SFP Evaluation Guidance Report through the completion of a reviewer checklist, which is included as an enclosure to this letter. TECHNICAL EVALUATION Section 4.0 of the SFP Evaluation Guidance Report provides SFP evaluation criteria for plants with GMRS peak spectral accelerations greater than 0.8g. These criteria address SFP structural elements (e.g., floors, walls, and supports);
By letter dated October 27, 2015 (ADAMS Accession No. ML15194A015), the NRC staff stated that SFP evaluation submittals for sites with GMRS peak spectral accelerations above 0.8g were expected by December 31, 2017.
non-structural elements (e.g., penetrations);
By letter dated July 11, 2017 (ADAMS Accession No. ML17192A168), the NRC issued a generic audit plan and entered into the audit process described in Office Instruction LIC-111, "Regulatory Audits," dated December 29, 2008 (ADAMS Accession No. ML082900195), to assist in the timely and efficient closure of activities associated with the 50.54(f) letter at Oconee. The staff used the audit process as described below during the SFP evaluation review.
seismically-induced SFP sloshing; and water losses due to heat-up and boil-off.
REVIEW OF LICENSEE SPENT FUEL POOL EVALUATION By letter dated December 4, 2017 (ADAMS Accession No. ML17348A075), the licensee submitted its SFP evaluation for Oconee. The NRC staff assessed the licensee's implementation of the SFP Evaluation Guidance Report through the completion of a reviewer checklist, which is included as an enclosure to this letter.
Section 4.0 also provides applicability criteria that enable licensees to determine if their specific conditions are within the bounds considered in developing some of the evaluation criteria in the guidance report. In its review, the staff confirmed that the SFP Evaluation Guidance Report methodology has been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. SPENT FUEL POOL STRUCTURAL EVALUATION Section 4.1 of the SFP Evaluation Guidance Report provides an SFP structural evaluation approach used to demonstrate that the SFP structure is sufficiently robust for the reevaluated seismic hazard. This approach supplements the guidance in Section 7 of the SPID and follows acceptable methods used to assess the seismic capacity of structures, systems, and components (SSCs) for nuclear power plants. In short, Sections 4.1.1 and 4.1.2 describe an acceptable method for licensees to use to calculate a site-specific seismic high confidence of E. Burchfield low probability of failure (HCLPF) value for the SFP that is then compared to the site-specific GMRS. The licensee stated that the SFP structural evaluation approach presented in the SFP Evaluation Guidance Report is applicable and, as a part of the audit process, provided site-specific data to the NRC staff to confirm the stated results for Oconee. As a part of the audit process, the NRC staff reviewed the information provided in Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, and confirmed that the site-specific HCLPF value calculated for Oconee's SFP followed the methodology of the SFP Evaluation Guidance Report and that the HCLPF value is greater than the GMRS. The staff concludes that SFP SSCs were appropriately evaluated and that the licensee has demonstrated that there is high confidence that the SFP structure is sufficiently robust to withstand ground motions with peak spectral accelerations up to and including the peak spectral acceleration of Oconee's GMRS. SPENT FUEL POOL NON-STRUCTURAL EVALUATION Section 4.2 of the SFP Evaluation Guidance Report provides criteria for evaluating the structural aspects of the SFP, such as piping connections, fuel gates, and anti-siphoning devices, as well as SFP sloshing and heat-up and boil-off of SFP water inventory.
TECHNICAL EVALUATION Section 4.0 of the SFP Evaluation Guidance Report provides SFP evaluation criteria for plants with GMRS peak spectral accelerations greater than 0.8g. These criteria address SFP structural elements (e.g., floors, walls, and supports); non-structural elements (e.g.,
Additionally, page 4-11 of the SFP Evaluation Guidance Report provides a summary of the pertinent SFP non-structural parameters important to the methodology described in Section 4.2. The licensee provided a table in its letter dated December 4, 2017, demonstrating that it followed the SFP non-structural evaluation approach presented in the SFP Evaluation Guidance Report and provided site-specific data to confirm its applicability.
penetrations); seismically-induced SFP sloshing; and water losses due to heat-up and boil-off.
The staff reviewed the structural information provided, which included Oconee's site-specific attributes, against the criteria described in the SFP Evaluation Guidance Report, and confirmed that the methods and conclusions are applicable to the Oconee site. Therefore, the staff concludes that the licensee adequately evaluated the non-structural considerations for SSCs whose failure could lead to potential drain-down of the SFP due to a seismic event. Further, the staff concludes that the licensee demonstrated that a potential drain-down of the SFP as a result of the reevaluated seismic hazard is unlikely.
Section 4.0 also provides applicability criteria that enable licensees to determine if their site-specific conditions are within the bounds considered in developing some of the evaluation criteria in the guidance report. In its review, the staff confirmed that the SFP Evaluation Guidance Report methodology has been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report.
AUDIT REPORT The July 11, 2017, generic audit plan describes the NRC staffs intention to issue an audit report that summarizes and documents the NRC's regulatory audit of licensee's submittals associated with reevaluated seismic hazard analyses.
SPENT FUEL POOL STRUCTURAL EVALUATION Section 4.1 of the SFP Evaluation Guidance Report provides an SFP structural evaluation approach used to demonstrate that the SFP structure is sufficiently robust for the reevaluated seismic hazard. This approach supplements the guidance in Section 7 of the SPID and follows acceptable methods used to assess the seismic capacity of structures, systems, and components (SSCs) for nuclear power plants. In short, Sections 4.1.1 and 4.1.2 describe an acceptable method for licensees to use to calculate a site-specific seismic high confidence of
The NRC staffs Oconee audit was limited to the review of the calculation discussed above. An audit summary document is included as Enclosure 2 to this letter. CONCLUSION The NRC staff reviewed the licensee's SFP evaluation report. Based on its review, the NRC staff concludes that the licensee's implementation of the SFP integrity evaluation met the criteria of the SFP Evaluation Guidance Report for Oconee and therefore, the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff further concludes that the licensee has demonstrated an adequate margin to preclude a potential drain-down of the SFP as a result of the reevaluated seismic hazard at Oconee.
 
E. Burchfield If you have any questions, please contact me at (301) 415-1617 or via e-mail at Frankie.Vega@nrc.gov.
E. Burchfield                                   low probability of failure (HCLPF) value for the SFP that is then compared to the site-specific GMRS.
Docket Nos. 50-269, 50-270, and 50-287  
The licensee stated that the SFP structural evaluation approach presented in the SFP Evaluation Guidance Report is applicable and, as a part of the audit process, provided site-specific data to the NRC staff to confirm the stated results for Oconee.
As a part of the audit process, the NRC staff reviewed the information provided in Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation,"
Revision 0, dated October 27, 2017, and confirmed that the site-specific HCLPF value calculated for Oconee's SFP followed the methodology of the SFP Evaluation Guidance Report and that the HCLPF value is greater than the GMRS. The staff concludes that SFP SSCs were appropriately evaluated and that the licensee has demonstrated that there is high confidence that the SFP structure is sufficiently robust to withstand ground motions with peak spectral accelerations up to and including the peak spectral acceleration of Oconee's GMRS.
SPENT FUEL POOL NON-STRUCTURAL EVALUATION Section 4.2 of the SFP Evaluation Guidance Report provides criteria for evaluating the non-structural aspects of the SFP, such as piping connections, fuel gates, and anti-siphoning devices, as well as SFP sloshing and heat-up and boil-off of SFP water inventory. Additionally, page 4-11 of the SFP Evaluation Guidance Report provides a summary of the pertinent SFP non-structural parameters important to the methodology described in Section 4.2.
The licensee provided a table in its letter dated December 4, 2017, demonstrating that it followed the SFP non-structural evaluation approach presented in the SFP Evaluation Guidance Report and provided site-specific data to confirm its applicability. The staff reviewed the non-structural information provided, which included Oconee's site-specific attributes, against the criteria described in the SFP Evaluation Guidance Report, and confirmed that the methods and conclusions are applicable to the Oconee site. Therefore, the staff concludes that the licensee adequately evaluated the non-structural considerations for SSCs whose failure could lead to potential drain-down of the SFP due to a seismic event. Further, the staff concludes that the licensee demonstrated that a potential drain-down of the SFP as a result of the reevaluated seismic hazard is unlikely.
AUDIT REPORT The July 11, 2017, generic audit plan describes the NRC staffs intention to issue an audit report that summarizes and documents the NRC's regulatory audit of licensee's submittals associated with reevaluated seismic hazard analyses. The NRC staffs Oconee audit was limited to the review of the calculation discussed above. An audit summary document is included as to this letter.
CONCLUSION The NRC staff reviewed the licensee's SFP evaluation report. Based on its review, the NRC staff concludes that the licensee's implementation of the SFP integrity evaluation met the criteria of the SFP Evaluation Guidance Report for Oconee and therefore, the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff further concludes that the licensee has demonstrated an adequate margin to preclude a potential drain-down of the SFP as a result of the reevaluated seismic hazard at Oconee.
 
E. Burchfield                               If you have any questions, please contact me at (301) 415-1617 or via e-mail at Frankie.Vega@nrc.gov.
Si:i~v Fran:ie Veg~ct Manager Beyond-Design-Basis Management Branch Division of Licensing Projects Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287


==Enclosures:==
==Enclosures:==
: 1. Technical Review Checklist  
: 1. Technical Review Checklist
: 2. NRC Staff Audit Summary cc w/encls: Distribution via Listserv Si:i~v Fran:ie Veg~ct Manager Beyond-Design-Basis Management Branch Division of Licensing Projects Office of Nuclear Reactor Regulation TECHNICAL REVIEW CHECKLIST BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO SPENT FUEL POOL EVALUATIONS FOR HIGH GROUND MOTION RESPONSE SPECTRUM SITES IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287 BACKGROUND By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, under Title 10 of the Code of Federal Regulations ( 10 CFR), Section 50.54(f) (hereafter referred to as the "50.54(f) letter").
: 2. NRC Staff Audit Summary cc w/encls: Distribution via Listserv
Enclosure 1 of the 50.54(f) letter requests addressees to reevaluate the seismic hazard at their site using present-day methods and guidance for licensing new nuclear power plants, and identify actions to address or modify, as necessary, plant components affected by the reevaluated seismic hazards. Enclosure 1, Item (4), of the 50.54(f) letter requested that licensees perform a comparison of the ground motion response spectrum (GMRS) with the safe shutdown earthquake (SSE). Enclosure 1, Item (9), requests that, when the GMRS exceeds the SSE in the 1 to 10 Hertz (Hz) frequency range, a seismic evaluation be made of the spent fuel pool (SFP). More specifically, plants were asked to consider all seismically induced failures that can lead to draining of the SFP. Additionally, by letter dated January 31, 2017 (ADAMS Accession No. ML 17031A171), the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) Report No. 3002009564 entitled, "Seismic Evaluation Guidance:
Spent Fuel Pool Integrity Evaluation" (SFP Evaluation Guidance Report). The SFP Evaluation Guidance Report supports the completion of SFP evaluations for sites with reevaluated seismic hazard exceedance in the 1 to 10 Hz frequency range. The NRC endorsed the SFP Evaluation Guidance Report by letter dated February 28, 2017 (ADAMS Accession No. ML 17034A408), as an acceptable method for licensees to use when responding to Item (9) in Enclosure 1 of the 50.54(f) letter. Licensee deviations from the SFP Evaluation Guidance should be discussed in their SFP evaluation submittal.
By letter dated December 4, 2017 (ADAMS Accession No. ML 17348A075), Duke Energy Carolinas, LLC (Duke, the licensee), provided an SFP report in response to Enclosure 1, Item (9), of the 50.54(f) letter for Oconee Nuclear Station, Units 1, 2, and 3 (Oconee).
The NRC staff performed its review of the licensee's submittal to assess whether the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff evaluated whether the SFP Evaluation Guidance Report methodology had been followed when calculating the specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. The NRC staff also confirmed that the requested information in response to Item (9) of the 50.54(f) letter was provided.
A review checklist was used for consistency and efficiency.
The application of this staff review is limited to the SFP evaluation as part of the seismic review as part of the Near-Term Task Force (NTTF} Recommendation


===2.1. Enclosure===
TECHNICAL REVIEW CHECKLIST BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO SPENT FUEL POOL EVALUATIONS FOR HIGH GROUND MOTION RESPONSE SPECTRUM SITES IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287 BACKGROUND By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, under Title 10 of the Code of Federal Regulations ( 10 CFR),
Section 50.54(f) (hereafter referred to as the "50.54(f) letter"). Enclosure 1 of the 50.54(f) letter requests addressees to reevaluate the seismic hazard at their site using present-day methods and guidance for licensing new nuclear power plants, and identify actions to address or modify, as necessary, plant components affected by the reevaluated seismic hazards. Enclosure 1, Item (4), of the 50.54(f) letter requested that licensees perform a comparison of the ground motion response spectrum (GMRS) with the safe shutdown earthquake (SSE). Enclosure 1, Item (9), requests that, when the GMRS exceeds the SSE in the 1 to 10 Hertz (Hz) frequency range, a seismic evaluation be made of the spent fuel pool (SFP). More specifically, plants were asked to consider all seismically induced failures that can lead to draining of the SFP.
Additionally, by letter dated January 31, 2017 (ADAMS Accession No. ML17031A171), the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) Report No. 3002009564 entitled, "Seismic Evaluation Guidance: Spent Fuel Pool Integrity Evaluation" (SFP Evaluation Guidance Report). The SFP Evaluation Guidance Report supports the completion of SFP evaluations for sites with reevaluated seismic hazard exceedance in the 1 to 10 Hz frequency range. The NRC endorsed the SFP Evaluation Guidance Report by letter dated February 28, 2017 (ADAMS Accession No. ML17034A408), as an acceptable method for licensees to use when responding to Item (9) in Enclosure 1 of the 50.54(f) letter. Licensee deviations from the SFP Evaluation Guidance should be discussed in their SFP evaluation submittal.
By letter dated December 4, 2017 (ADAMS Accession No. ML17348A075), Duke Energy Carolinas, LLC (Duke, the licensee), provided an SFP report in response to Enclosure 1, Item (9), of the 50.54(f) letter for Oconee Nuclear Station, Units 1, 2, and 3 (Oconee). The NRC staff performed its review of the licensee's submittal to assess whether the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff evaluated whether the SFP Evaluation Guidance Report methodology had been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. The NRC staff also confirmed that the requested information in response to Item (9) of the 50.54(f) letter was provided.
A review checklist was used for consistency and efficiency. The application of this staff review is limited to the SFP evaluation as part of the seismic review as part of the Near-Term Task Force (NTTF} Recommendation 2.1.
Enclosure 1


1 NTTF Recommendation  
NTTF Recommendation 2.1 Spent Fuel Pool Evaluations Technical Review Checklist for Oconee Nuclear Station, Units 1, 2, and 3 Site Parameters:
 
I.       Site-Specific GMRS The licensee:
===2.1 Spent===
* Used the site-specific GMRS hazard, consistent with the                       Yes information in the Seismic Hazard and Screening Report (SHSR) or its update, that was evaluated and accepted in the NRC staff assessment when calculating the SFP high confidence of low probability of failure (HCLPF) value.
Fuel Pool Evaluations Technical Review Checklist for Oconee Nuclear Station, Units 1, 2, and 3 Site Parameters:
Notes from the reviewer:
I. Site-Specific GMRS The licensee:
: 1. The NRC staff reviewed the licensee's Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, and Simpson Gumpertz & Heger (SGH) calculation 148216-CA-021, "Seismic Response of the ONS Auxiliary Building Including SSI Effects," Revision 0, dated September 20, 2016, as a part of the audit process for Oconee. The staff notes that the calculations derive seismic input values for the Auxiliary building that were ultimately generated by the NRC-accepted GMRS. See conclusion below for details.
* Used the site-specific GMRS hazard, consistent with the information in the Seismic Hazard and Screening Report (SHSR) or its update, that was evaluated and accepted in the NRC staff assessment when calculating the SFP high confidence of low probability of failure (HCLPF) value. Notes from the reviewer:
Deviation(s) or Deficiency(ies), and Resolution:
Yes 1. The NRC staff reviewed the licensee's Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, and Simpson Gumpertz & Heger (SGH) calculation 148216-CA-021, "Seismic Response of the ONS Auxiliary Building Including SSI Effects," Revision 0, dated September 20, 2016, as a part of the audit process for Oconee. The staff notes that the calculations derive seismic input values for the Auxiliary building that were ultimately generated by the NRC-accepted GMRS. See conclusion below for details. Deviation(s) or Deficiency(ies), and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes that:
The NRC staff concludes that:
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Structural Parameters:
Structural Parameters:
II. Seismic Design of the SFP Structure The licensee:
II. Seismic Design of the SFP Structure The licensee:
* Performed site-specific calculations to demonstrate that the limiting SFP HCLPF capacity value is greater than the peak spectral acceleration of the site-specific GMRS. Notes from the reviewer:
* Performed site-specific calculations to demonstrate that the limiting         Yes SFP HCLPF capacity value is greater than the peak spectral acceleration of the site-specific GMRS.
Yes 1. The NRC staff confirmed that the licensee followed the methodology described in the SFP Evaluation Guidance Report in Jensen Hughes calculation No. 1 CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, to calculate an SFP HCLPF capacity.
Notes from the reviewer:
The resulting HCLPF value of 1.39g is greater than the site-specific GMRS peak spectral acceleration of .869; therefore, it is reasonable to conclude that the SFP has sufficient capacity to withstand a seismic event at least up to the GMRS without failure that would lead to a rapid draindown.
: 1. The NRC staff confirmed that the licensee followed the methodology described in the SFP Evaluation Guidance Report in Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, to calculate an SFP HCLPF capacity. The resulting HCLPF value of 1.39g is greater than the site-specific GMRS peak spectral acceleration of .869; therefore, it is reasonable to conclude that the SFP has sufficient capacity to withstand a seismic event at least up to the GMRS without failure that would lead to a rapid draindown.
Deviation(s) or Deficiency(ies), and Resolution:
Deviation(s) or Deficiency(ies), and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
Line 72: Line 80:
* The SFP has sufficient capacity to withstand a seismic event at least up to the GMRS without failure that would lead to a rapid draindown.
* The SFP has sufficient capacity to withstand a seismic event at least up to the GMRS without failure that would lead to a rapid draindown.
Ill. SFP Structure Included in the Civil Inspection Program Performed in Accordance with Maintenance Rule The licensee:
Ill. SFP Structure Included in the Civil Inspection Program Performed in Accordance with Maintenance Rule The licensee:
* Stated that the SFP structure is included in the Civil Inspection Program performed in accordance with Maintenance Rule ( 10 CFR 50.65). Notes from the reviewer:
* Stated that the SFP structure is included in the Civil Inspection             Yes Program performed in accordance with Maintenance Rule ( 10 CFR 50.65).
Yes 1. The licensee stated that the SFP structure is included in the Oconee Civil Inspection Program, Procedure AD-EG-ONS-1214, "Condition Monitoring of Structures," Revision 1 ". Updated Final Safety Analysis Report (UFSAR) Section 18.3.13, "Inspection Program for Civil Engineering Structures and Components," describes this program.
Notes from the reviewer:
: 1. The licensee stated that the SFP structure is included in the Oconee Civil Inspection Program, Procedure AD-EG-ONS-1214, "Condition Monitoring of Structures,"
Revision 1". Updated Final Safety Analysis Report (UFSAR) Section 18.3.13, "Inspection Program for Civil Engineering Structures and Components," describes this program.
Deviation(s) or Deficiency(ies}, and Resolution:
Deviation(s) or Deficiency(ies}, and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes that:
The NRC staff concludes that:
* The SFP structure is included in the Civil Inspection Program performed in accordance with Maintenance Rule (10 CFR 50.65). Non-Structural Parameters:
* The SFP structure is included in the Civil Inspection Program performed in accordance with Maintenance Rule (10 CFR 50.65).
Non-Structural Parameters:
IV. Applicability of Piping Evaluation The licensee:
IV. Applicability of Piping Evaluation The licensee:
* Stated that there are no piping penetrations attached to the SFP more than 6 feet (ft.) below the surface of the water and cited plant drawings (0-443 & 0-2443). Notes from the reviewer:
* Stated that there are no piping penetrations attached to the SFP             Yes more than 6 feet (ft.) below the surface of the water and cited plant drawings (0-443 & 0-2443).
Yes 1. The licensee stated that all SFP penetrations are located above the SFP normal water level. Deviation{s) or Deficiency{ies}, and Resolution:
Notes from the reviewer:
: 1. The licensee stated that all SFP penetrations are located above the SFP normal water level.
Deviation{s) or Deficiency{ies}, and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes that:
The NRC staff concludes that:
* There are no piping penetrations attached to the SFP more than 6 ft. below the surface of the water. V. Ductile Behavior of SFP Gates The licensee:
* There are no piping penetrations attached to the SFP more than 6 ft. below the surface of the water.
* Stated that the SFP gate is constructed from a ductile material (e.g . aluminum or stainless steel alloys). Notes from the reviewer:
V.     Ductile Behavior of SFP Gates The licensee:
No 1. The Licensee stated that Oconee SFPs have fuel transfer tubes and not SFP gates. The licensee also stated that the transfer tubes are sealed closed with a bolted steel flanged cover and are constructed from a stainless steel alloy. UFSAR Section 9.1.4.2 also states that during reactor operations, bolted and gasketed closure plates, located on the reactor building flanges of the fuel transfer tubes, isolate the fuel transfer canal from the spent fuel pool. Therefore, according to the SFP guidance, the fuel transfer tubes would not be a potential drain down path following an earthquake.
* Stated that the SFP gate is constructed from a ductile material (e.g .       No aluminum or stainless steel alloys).
Notes from the reviewer:
: 1. The Licensee stated that Oconee SFPs have fuel transfer tubes and not SFP gates.
The licensee also stated that the transfer tubes are sealed closed with a bolted steel flanged cover and are constructed from a stainless steel alloy. UFSAR Section 9.1.4.2 also states that during reactor operations, bolted and gasketed closure plates, located on the reactor building flanges of the fuel transfer tubes, isolate the fuel transfer canal from the spent fuel pool. Therefore, according to the SFP guidance, the fuel transfer tubes would not be a potential drain down path following an earthquake.
Deviation(s) or Deficiency(ies), and Resolution:
Deviation(s) or Deficiency(ies), and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes that:
The NRC staff concludes that:
* The SFP transfer tubes are constructed from a material expected to exhibit ductile behavior under higher seismic demands. VI. Siphoning Evaluation The licensee:
* The SFP transfer tubes are constructed from a material expected to exhibit ductile behavior under higher seismic demands.
* Stated that anti-siphoning devices are installed on piping systems Yes that could lead to siphoning inventory from the SFP.
VI. Siphoning Evaluation The licensee:
* In cases where anti-siphoning devices were not included on the N/A applicable piping, a description documenting the evaluation performed to determine the seismic adequacy of the piping is provided.
* Stated that anti-siphoning devices are installed on piping systems               Yes that could lead to siphoning inventory from the SFP.
* Stated that the piping of the SFP cooling system cannot lead to rapid Yes drain down due to siphoning.
* In cases where anti-siphoning devices were not included on the                   N/A applicable piping, a description documenting the evaluation performed to determine the seismic adequacy of the piping is provided.
* Stated that no anti-siphoning devices are attached to 2" or smaller piping with extremely large extended operators.
* Stated that the piping of the SFP cooling system cannot lead to rapid             Yes drain down due to siphoning.
Yes
* Stated that no anti-siphoning devices are attached to 2" or smaller Yes piping with extremely large extended operators.
* Provided a seismic adequacy evaluation, in accordance with NP-6041, for cases where active siphoning devices are attached to N/A 2" or smaller piping with extremely large extended operators.
* Provided a seismic adequacy evaluation, in accordance with N/A NP-6041, for cases where active siphoning devices are attached to 2" or smaller piping with extremely large extended operators.
Notes from the reviewer:  
Notes from the reviewer:
: 1. The licensee stated that the fuel pool piping is arranged so that the pool cannot be inadvertently drained to uncover the fuel. The licensee referenced plant design document, "BDB [beyond-design basis] OSS-0254.00-00-1006," and described that either pipes do not extent more than four feet below the normal pool water level or siphon breakers are present in SFP-attached piping that could lead to siphoning of water. Deviation(s) or Deficiency(ies), and Resolution:
: 1. The licensee stated that the fuel pool piping is arranged so that the pool cannot be inadvertently drained to uncover the fuel. The licensee referenced plant design document, "BDB [beyond-design basis] OSS-0254.00-00-1006," and described that either pipes do not extent more than four feet below the normal pool water level or siphon breakers are present in SFP-attached piping that could lead to siphoning of water.
Deviation(s) or Deficiency(ies), and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes that:
The NRC staff concludes that:
* Anti-siphoning devices exist in applicable piping systems that could Yes lead to siphoning water from the SFP.
* Anti-siphoning devices exist in applicable piping systems that could             Yes lead to siphoning water from the SFP.
* Piping of the SFP cooling system is not likely to lead to rapid draindown due to siphoning.
* Piping of the SFP cooling system is not likely to lead to rapid         Yes draindown due to siphoning.
* No active anti-siphoning devices are attached to 2" or smaller piping with extremely large extended operators.
* No active anti-siphoning devices are attached to 2" or smaller piping   Yes with extremely large extended operators.
VII. Sloshing Evaluation The licensee:
VII. Sloshing Evaluation The licensee:
* Specified the SFP dimensions  
* Specified the SFP dimensions {length, width, and depth} .             Yes
{length, width, and depth} .
* Specified that the SFP dimensions are bounded by the dimensions       Yes specified in the report (i.e., SFP length and width <125 ft.; SFP depth >36 ft.).
* Specified that the SFP dimensions are bounded by the dimensions specified in the report (i.e., SFP length and width <125 ft.; SFP depth >36 ft.). Notes from the reviewer:  
Notes from the reviewer:
: 1. SFP dimensions (Units 1 & 2) (Oconee Site drawings 0-18C) -SFP Length -84 ft. 3 in. -SFP Width -24 ft. -SFP Depth -38 ft. 2. SFP dimensions (Unit 3) (Oconee Site drawings 0-2154-S).  
: 1. SFP dimensions (Units 1 & 2) (Oconee Site drawings 0-18C)
-SFP Length -58 ft. -SFP Width -24 ft. -SFP Depth -38 ft. Deviation(s) or Deficiency(ies}, and Resolution:
        - SFP Length - 84 ft. 3 in.
        - SFP Width - 24 ft.
        - SFP Depth - 38 ft.
: 2. SFP dimensions (Unit 3) (Oconee Site drawings 0-2154-S).
        - SFP Length - 58 ft.
        - SFP Width - 24 ft.
        - SFP Depth - 38 ft.
Deviation(s) or Deficiency(ies}, and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes that:
The NRC staff concludes that:
* SFP dimensions are bounded by the dimensions specified in the report (i.e., SFP length and width <125 ft.; SFP depth >36 ft.). VIII. Evaporation Evaluation The licensee:
* SFP dimensions are bounded by the dimensions specified in the         Yes report (i.e., SFP length and width <125 ft.; SFP depth >36 ft.).
* Provided the surface area of the plant's SFP .
VIII. Evaporation Evaluation The licensee:
* Stated that the surface area of the plant's SFP is greater than 500 ft 2
* Provided the surface area of the plant's SFP .                       Yes
* Provided the licensed reactor core thermal power .
* Stated that the surface area of the plant's SFP is greater than       Yes 500 ft2
* Stated that the reactor core thermal power is less than 4,000 megawatt thermal (MW1) per unit. Yes Yes Yes Yes Yes Yes Yes Yes Yes Notes from the reviewer:  
* Provided the licensed reactor core thermal power.                     Yes Yes
: 1. Surface area of pool (Unit 1 & 2) = 2022 ft2 (Oconee Site drawing 0-18C) 2. Surface area of pool (Unit 3) = 1392 ft 2 (Oconee Site Drawing 0-2154-S)  
* Stated that the reactor core thermal power is less than 4,000 megawatt thermal (MW1) per unit.
: 3. Reactor thermal power= 2568 MW1 (each Unit) (UFSAR Section 1.1) Deviation(s) or Deficiency(ies), and Resolution:
Notes from the reviewer:
: 1. Surface area of pool (Unit 1 & 2) = 2022 ft2 (Oconee Site drawing 0-18C)
: 2. Surface area of pool (Unit 3) = 1392 ft 2 (Oconee Site Drawing 0-2154-S)
: 3. Reactor thermal power= 2568 MW1 (each Unit) (UFSAR Section 1.1)
Deviation(s) or Deficiency(ies), and Resolution:
No deviations or deficiencies were identified.
No deviations or deficiencies were identified.
The NRC staff concludes:
The NRC staff concludes:
* The surface area of the plant's SFP is greater than 500 ft 2.
* The surface area of the plant's SFP is greater than 500 ft 2.               Yes
* The reactor core thermal power is less than 4,000 MW1 per unit.
* The reactor core thermal power is less than 4,000 MW1 per unit.             Yes


== Conclusions:==
==
Conclusions:==


Yes Yes The NRC staff reviewed the licensee's SFP evaluation report. Based on its review, the NRC staff concludes that the SFP Evaluation Guidance Report methodology has been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. Therefore, the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff further concludes that the licensee has demonstrated an adequate margin to preclude a potential drain-down of the SFP as a result of the reevalutaed seismic hazard at Oconee.
The NRC staff reviewed the licensee's SFP evaluation report. Based on its review, the NRC staff concludes that the SFP Evaluation Guidance Report methodology has been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. Therefore, the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff further concludes that the licensee has demonstrated an adequate margin to preclude a potential drain-down of the SFP as a result of the reevalutaed seismic hazard at Oconee.
AUDIT  
AUDIT  


==SUMMARY==
==SUMMARY==
BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID L-2017-JLD-0056)
BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID L-2017-JLD-0056)
BACKGROUND AND AUDIT BASIS By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML 12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information under Title 10 of the Code of Federal Regulations ( 10 CFR), Section 50.54(f) (hereafter referred to as the 50.54(f) letter). Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate the seismic hazards for their sites using present-day methods and regulatory guidance used by the NRC staff when reviewing applications for early site permits and combined licenses.
BACKGROUND AND AUDIT BASIS By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information under Title 10 of the Code of Federal Regulations ( 10 CFR),
By letter dated October 27, 2015 {ADAMS Accession No. ML 15194A015), the NRC made a determination of which licensees were to perform: (1) a seismic probabilistic risk assessment (SPRA), (2) limited scope evaluations, or (3) no further actions based on a comparison of the reevaluated seismic hazard and the site's design-basis earthquake. (Note: Some plant-specific changes regarding whether an SPRA was needed or limited scope evaluations were needed at certain sites have occurred since the issuance of the October 27, 2015, letter.) By letter dated July 11, 2017 (ADAMS Accession No. ML 17192A 168), the NRC issued a generic audit plan to Oconee Nuclear Station, Units 1, 2, and 3 (Oconee) and entered into the audit process described in Office Instruction LIC-111, "Regulatory Audits," dated December 29, 2008 (ADAMS Accession No. ML082900195), to assist in the timely and efficient closure of activities associated with the 50.54(f) letter. REGULATORY AUDIT SCOPE AND METHODOLOGY The areas of focus for the regulatory audit are the information contained in the spent fuel pool (SFP) evaluation submittal and all associated and relevant supporting documentation used in the development of the SFP evaluation including, but not limited to, methodology, process information, calculations, computer models, etc. AUDIT ACTIVITIES The Oconee audit took place at the NRC Headquarters in Rockville, MD, beginning on July 14, 2018. Licensee personnel participated remotely, via email, from their respective offices. A list of the licensee staff and NRC staff that participated in the audit is contained in Table 1. Enclosure 2
Section 50.54(f) (hereafter referred to as the 50.54(f) letter). Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate the seismic hazards for their sites using present-day methods and regulatory guidance used by the NRC staff when reviewing applications for early site permits and combined licenses.
Table 1 NRC Staff Licensee Staff Name I Title Name I Title Frankie Vega I Project ManaQer Paul Guill I Sr. LicensinQ Engineer On June 14, 2018, the NRC staff requested, via email, that the licensee upload Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, which was the calculation that was performed to determine the high confidence low probability of failure (HCLPF) value for the SFP onto the licensee's ePortal (electronic reading room). In addition, the staff requested a series of plant drawings and procedures (detailed below) that were refereced as part of the SFP submmital.
By letter dated October 27, 2015 {ADAMS Accession No. ML15194A015), the NRC made a determination of which licensees were to perform: (1) a seismic probabilistic risk assessment (SPRA), (2) limited scope evaluations, or (3) no further actions based on a comparison of the reevaluated seismic hazard and the site's design-basis earthquake. (Note: Some plant-specific changes regarding whether an SPRA was needed or limited scope evaluations were needed at certain sites have occurred since the issuance of the October 27, 2015, letter.)
The licensee uploaded the requested documents onto the ePortal on June 25, 2018, as requested by the NRC staff. DOCUMENTS AUDITED
By letter dated July 11, 2017 (ADAMS Accession No. ML17192A168), the NRC issued a generic audit plan to Oconee Nuclear Station, Units 1, 2, and 3 (Oconee) and entered into the audit process described in Office Instruction LIC-111, "Regulatory Audits," dated December 29, 2008 (ADAMS Accession No. ML082900195), to assist in the timely and efficient closure of activities associated with the 50.54(f) letter.
REGULATORY AUDIT SCOPE AND METHODOLOGY The areas of focus for the regulatory audit are the information contained in the spent fuel pool (SFP) evaluation submittal and all associated and relevant supporting documentation used in the development of the SFP evaluation including, but not limited to, methodology, process information, calculations, computer models, etc.
AUDIT ACTIVITIES The Oconee audit took place at the NRC Headquarters in Rockville, MD, beginning on July 14, 2018. Licensee personnel participated remotely, via email, from their respective offices. A list of the licensee staff and NRC staff that participated in the audit is contained in Table 1.
Enclosure 2
 
Table 1 NRC Staff                                       Licensee Staff Name                   I Title                       Name                 I Title Frankie Vega           I Project ManaQer             Paul Guill           I Sr. LicensinQ Engineer On June 14, 2018, the NRC staff requested, via email, that the licensee upload Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, which was the calculation that was performed to determine the high confidence low probability of failure (HCLPF) value for the SFP onto the licensee's ePortal (electronic reading room). In addition, the staff requested a series of plant drawings and procedures (detailed below) that were refereced as part of the SFP submmital. The licensee uploaded the requested documents onto the ePortal on June 25, 2018, as requested by the NRC staff.
DOCUMENTS AUDITED
* AD-EG-ONS-1214, "Condition Monitoring of Structures," Revision O;
* AD-EG-ONS-1214, "Condition Monitoring of Structures," Revision O;
* 0-443, "Piping Layout Plan and Sections -SF Pool -El. 844-0"-Auxiliary Building, Units 1 & 2";
* 0-443, "Piping Layout Plan and Sections - SF Pool - El. 844-0"-Auxiliary Building, Units 1 & 2";
* 0-2443, "Piping Layout Plan and Sections -SF Pool -El. 844F-O"-Auxiliary Building, Unit 3;
* 0-2443, "Piping Layout Plan and Sections - SF Pool - El. 844F-O"-Auxiliary Building, Unit 3;
* OFD-104A-1.1, "Flow Diagram of Spent Fuel Cooling System, Units 1 & 2";
* OFD-104A-1.1, "Flow Diagram of Spent Fuel Cooling System, Units 1 & 2";
* OFD-104A-3.11, "Flow Diagram of Spent Fuel Cooling System, Unit 3";
* OFD-104A-3.11, "Flow Diagram of Spent Fuel Cooling System, Unit 3";
Line 143: Line 178:
* OM-271-0235-001, "Transfer Tube Assy";
* OM-271-0235-001, "Transfer Tube Assy";
* DBD OSS-0254.00-00-1006, "Desing Basis Specification for the Spent Fuel Pool Cooling System," Revision 23;
* DBD OSS-0254.00-00-1006, "Desing Basis Specification for the Spent Fuel Pool Cooling System," Revision 23;
* SGH Calculation 148216-CA-021, "Seismic Response of the ONS Auxiliary Building Including SSI Effects," Revision 0. OPEN ITEMS AND REQUEST FOR INFORMATION Following the review of the SFP HCLPF calculation, there were no open items identified by the NRC staff that required proposed closure paths, and there were no requests for information discussed or planned to be issued. DEVIATIONS FROM AUDIT PLAN There were no deviations from the July 11, 2017, generic audit plan. AUDIT CONCLUSION The issuance of this document, containing the staff's review of the SFP evaluation submittal, concludes the SFP audit process for Oconee.
* SGH Calculation 148216-CA-021, "Seismic Response of the ONS Auxiliary Building Including SSI Effects," Revision 0.
E. Burchfield
OPEN ITEMS AND REQUEST FOR INFORMATION Following the review of the SFP HCLPF calculation, there were no open items identified by the NRC staff that required proposed closure paths, and there were no requests for information discussed or planned to be issued.
DEVIATIONS FROM AUDIT PLAN There were no deviations from the July 11, 2017, generic audit plan.
AUDIT CONCLUSION The issuance of this document, containing the staff's review of the SFP evaluation submittal, concludes the SFP audit process for Oconee.


==SUBJECT:==
ML18197A201                             *via e-mail OFFICE NRR/DLP/PBMB/PM NRR/DLP/PBMB/LA           NRR/DLP/PBMB/BC (A)
OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 -STAFF REVIEW OF SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC DATED July 25, 2018 DISTRIBUTION:
NAME       FVega             SLent               BTitus DATE       07/18/2018         07/16/2018         07/25/2018 OFFICE NRR/DLP/PBMB/PM NAME       FVega DATE       07/25/2018}}
PUBLIC RidsNrrDlpPbmbResource RidsNrrDorlLpl2-1 Resource FVega, NRR RidsACRS_MailCTR Resource PBMB R/F BTitus, NRR RidsNrrPMOconeeResource RidsNrrLASLent Resource RidsRgn2MailCenter Resource ADAMS Accession No.: ML18197A201  
*via e-mail OFFICE NRR/DLP/PBMB/PM NRR/DLP/PBMB/LA NRR/DLP/PBMB/BC (A) NAME FVega SLent BTitus DATE 07/18/2018 07/16/2018 07/25/2018 OFFICE NRR/DLP/PBMB/PM NAME FVega DATE 07/25/2018 OFFICIAL RECORD COPY}}

Latest revision as of 20:06, 2 February 2020

Staff Review of Spent Fuel Pool Evaluation Associated with Reevaluated Seismic Hazard Implementation Near- Task Force Recommendation 2.1: Seismic
ML18197A201
Person / Time
Site: Oconee  Duke Energy icon.png
Issue date: 07/25/2018
From: Frankie Vega
Beyond-Design-Basis Management Branch
To: Burchfield E
Duke Energy Carolinas
Vega F
References
EPID L-2017-JLD-0056
Download: ML18197A201 (15)
v • d • e


Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 July 25, 2018 Mr. Ed Burchfield, Jr.

Site Vice President Oconee Nuclear Station Duke Energy Carolinas, LLC 7800 Rochester Highway Seneca, SC 29672-0752

SUBJECT:

OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3- STAFF REVIEW OF SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID L-2017-JLD-0056)

Dear Mr. Burchfield:

The purpose of this letter is to inform Duke Energy Carolinas, LLC (Duke, the licensee), of the results of the U.S. Nuclear Regulatory Commission (NRC) staff's review of the spent fuel pool (SFP) evaluation for Oconee Nuclear Station, Units 1, 2, and 3 (Oconee), which was submitted in response to Item (9) of Enclosure 1 of the NRC's March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), request for information issued under Title 10 of the Code of Federal Regulations, Section 50.54(f) (hereafter referred to as the 50.54(f) letter). The NRC staff concludes that the licensee's assessment was performed consistent with the NRG-endorsed SFP Evaluation Guidance Report and that the licensee has provided sufficient information to complete the response to Item (9) of the 50.54(f) letter.

BACKGROUND On March 12, 2012, the NRC issued the 50.54(f) letter as part of implementing lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate seismic hazards at their sites using present-day methodologies and guidance. Enclosure 1, Item (4), of the 50.54(f) letter requested that licensees perform a comparison of the ground motion response spectrum (GMRS) and the safe shutdown earthquake (SSE). The staff's assessment of the information provided in response to Items (1 )-(3) and (5)-(7) and the comparison portion of Item (4) of the 50.54(f) letter was provided by letter dated July 22, 2015 (ADAMS Accession No. ML15201A008). Enclosure 1, Item (9), of the 50.54(f) letter requested that, when the GMRS exceeds the SSE in the 1 to 10 Hertz frequency range, the licensee provide a seismic evaluation of the SFP. More specifically, licensees were asked to consider " ... all seismically induced failures that can lead to draining of the SFP."

E. Burchfield By letter dated January 31, 2017 (ADAMS Accession No. ML17031A171), the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) Report No. 3002009564 entitled, "Seismic Evaluation Guidance: Spent Fuel Pool Integrity Evaluation" (SFP Evaluation Guidance Report). The SFP Evaluation Guidance Report provides criteria for evaluating the seismic adequacy of an SFP to the reevaluated GMRS hazard levels. This report supplements the guidance in EPRI Report 1025287, "Seismic Evaluation Guidance: Screening, Prioritization and Implementation Details (SPID)" (ADAMS Accession No. ML12333A170). The NRC endorsed the SFP Evaluation Guidance Report by letter dated February 28, 2017 (ADAMS Accession No. ML17034A408), as an acceptable method for licensees to use when responding to Item (9) in Enclosure 1 of the 50.54(f) letter.

By letter dated October 27, 2015 (ADAMS Accession No. ML15194A015), the NRC staff stated that SFP evaluation submittals for sites with GMRS peak spectral accelerations above 0.8g were expected by December 31, 2017.

By letter dated July 11, 2017 (ADAMS Accession No. ML17192A168), the NRC issued a generic audit plan and entered into the audit process described in Office Instruction LIC-111, "Regulatory Audits," dated December 29, 2008 (ADAMS Accession No. ML082900195), to assist in the timely and efficient closure of activities associated with the 50.54(f) letter at Oconee. The staff used the audit process as described below during the SFP evaluation review.

REVIEW OF LICENSEE SPENT FUEL POOL EVALUATION By letter dated December 4, 2017 (ADAMS Accession No. ML17348A075), the licensee submitted its SFP evaluation for Oconee. The NRC staff assessed the licensee's implementation of the SFP Evaluation Guidance Report through the completion of a reviewer checklist, which is included as an enclosure to this letter.

TECHNICAL EVALUATION Section 4.0 of the SFP Evaluation Guidance Report provides SFP evaluation criteria for plants with GMRS peak spectral accelerations greater than 0.8g. These criteria address SFP structural elements (e.g., floors, walls, and supports); non-structural elements (e.g.,

penetrations); seismically-induced SFP sloshing; and water losses due to heat-up and boil-off.

Section 4.0 also provides applicability criteria that enable licensees to determine if their site-specific conditions are within the bounds considered in developing some of the evaluation criteria in the guidance report. In its review, the staff confirmed that the SFP Evaluation Guidance Report methodology has been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report.

SPENT FUEL POOL STRUCTURAL EVALUATION Section 4.1 of the SFP Evaluation Guidance Report provides an SFP structural evaluation approach used to demonstrate that the SFP structure is sufficiently robust for the reevaluated seismic hazard. This approach supplements the guidance in Section 7 of the SPID and follows acceptable methods used to assess the seismic capacity of structures, systems, and components (SSCs) for nuclear power plants. In short, Sections 4.1.1 and 4.1.2 describe an acceptable method for licensees to use to calculate a site-specific seismic high confidence of

E. Burchfield low probability of failure (HCLPF) value for the SFP that is then compared to the site-specific GMRS.

The licensee stated that the SFP structural evaluation approach presented in the SFP Evaluation Guidance Report is applicable and, as a part of the audit process, provided site-specific data to the NRC staff to confirm the stated results for Oconee.

As a part of the audit process, the NRC staff reviewed the information provided in Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation,"

Revision 0, dated October 27, 2017, and confirmed that the site-specific HCLPF value calculated for Oconee's SFP followed the methodology of the SFP Evaluation Guidance Report and that the HCLPF value is greater than the GMRS. The staff concludes that SFP SSCs were appropriately evaluated and that the licensee has demonstrated that there is high confidence that the SFP structure is sufficiently robust to withstand ground motions with peak spectral accelerations up to and including the peak spectral acceleration of Oconee's GMRS.

SPENT FUEL POOL NON-STRUCTURAL EVALUATION Section 4.2 of the SFP Evaluation Guidance Report provides criteria for evaluating the non-structural aspects of the SFP, such as piping connections, fuel gates, and anti-siphoning devices, as well as SFP sloshing and heat-up and boil-off of SFP water inventory. Additionally, page 4-11 of the SFP Evaluation Guidance Report provides a summary of the pertinent SFP non-structural parameters important to the methodology described in Section 4.2.

The licensee provided a table in its letter dated December 4, 2017, demonstrating that it followed the SFP non-structural evaluation approach presented in the SFP Evaluation Guidance Report and provided site-specific data to confirm its applicability. The staff reviewed the non-structural information provided, which included Oconee's site-specific attributes, against the criteria described in the SFP Evaluation Guidance Report, and confirmed that the methods and conclusions are applicable to the Oconee site. Therefore, the staff concludes that the licensee adequately evaluated the non-structural considerations for SSCs whose failure could lead to potential drain-down of the SFP due to a seismic event. Further, the staff concludes that the licensee demonstrated that a potential drain-down of the SFP as a result of the reevaluated seismic hazard is unlikely.

AUDIT REPORT The July 11, 2017, generic audit plan describes the NRC staffs intention to issue an audit report that summarizes and documents the NRC's regulatory audit of licensee's submittals associated with reevaluated seismic hazard analyses. The NRC staffs Oconee audit was limited to the review of the calculation discussed above. An audit summary document is included as to this letter.

CONCLUSION The NRC staff reviewed the licensee's SFP evaluation report. Based on its review, the NRC staff concludes that the licensee's implementation of the SFP integrity evaluation met the criteria of the SFP Evaluation Guidance Report for Oconee and therefore, the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff further concludes that the licensee has demonstrated an adequate margin to preclude a potential drain-down of the SFP as a result of the reevaluated seismic hazard at Oconee.

E. Burchfield If you have any questions, please contact me at (301) 415-1617 or via e-mail at Frankie.Vega@nrc.gov.

Si:i~v Fran:ie Veg~ct Manager Beyond-Design-Basis Management Branch Division of Licensing Projects Office of Nuclear Reactor Regulation Docket Nos. 50-269, 50-270, and 50-287

Enclosures:

1. Technical Review Checklist
2. NRC Staff Audit Summary cc w/encls: Distribution via Listserv

TECHNICAL REVIEW CHECKLIST BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO SPENT FUEL POOL EVALUATIONS FOR HIGH GROUND MOTION RESPONSE SPECTRUM SITES IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 DOCKET NOS. 50-269, 50-270, AND 50-287 BACKGROUND By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information to all power reactor licensees and holders of construction permits in active or deferred status, under Title 10 of the Code of Federal Regulations ( 10 CFR),

Section 50.54(f) (hereafter referred to as the "50.54(f) letter"). Enclosure 1 of the 50.54(f) letter requests addressees to reevaluate the seismic hazard at their site using present-day methods and guidance for licensing new nuclear power plants, and identify actions to address or modify, as necessary, plant components affected by the reevaluated seismic hazards. Enclosure 1, Item (4), of the 50.54(f) letter requested that licensees perform a comparison of the ground motion response spectrum (GMRS) with the safe shutdown earthquake (SSE). Enclosure 1, Item (9), requests that, when the GMRS exceeds the SSE in the 1 to 10 Hertz (Hz) frequency range, a seismic evaluation be made of the spent fuel pool (SFP). More specifically, plants were asked to consider all seismically induced failures that can lead to draining of the SFP.

Additionally, by letter dated January 31, 2017 (ADAMS Accession No. ML17031A171), the Nuclear Energy Institute (NEI) submitted the Electric Power Research Institute (EPRI) Report No. 3002009564 entitled, "Seismic Evaluation Guidance: Spent Fuel Pool Integrity Evaluation" (SFP Evaluation Guidance Report). The SFP Evaluation Guidance Report supports the completion of SFP evaluations for sites with reevaluated seismic hazard exceedance in the 1 to 10 Hz frequency range. The NRC endorsed the SFP Evaluation Guidance Report by letter dated February 28, 2017 (ADAMS Accession No. ML17034A408), as an acceptable method for licensees to use when responding to Item (9) in Enclosure 1 of the 50.54(f) letter. Licensee deviations from the SFP Evaluation Guidance should be discussed in their SFP evaluation submittal.

By letter dated December 4, 2017 (ADAMS Accession No. ML17348A075), Duke Energy Carolinas, LLC (Duke, the licensee), provided an SFP report in response to Enclosure 1, Item (9), of the 50.54(f) letter for Oconee Nuclear Station, Units 1, 2, and 3 (Oconee). The NRC staff performed its review of the licensee's submittal to assess whether the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff evaluated whether the SFP Evaluation Guidance Report methodology had been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. The NRC staff also confirmed that the requested information in response to Item (9) of the 50.54(f) letter was provided.

A review checklist was used for consistency and efficiency. The application of this staff review is limited to the SFP evaluation as part of the seismic review as part of the Near-Term Task Force (NTTF} Recommendation 2.1.

Enclosure 1

NTTF Recommendation 2.1 Spent Fuel Pool Evaluations Technical Review Checklist for Oconee Nuclear Station, Units 1, 2, and 3 Site Parameters:

I. Site-Specific GMRS The licensee:

  • Used the site-specific GMRS hazard, consistent with the Yes information in the Seismic Hazard and Screening Report (SHSR) or its update, that was evaluated and accepted in the NRC staff assessment when calculating the SFP high confidence of low probability of failure (HCLPF) value.

Notes from the reviewer:

1. The NRC staff reviewed the licensee's Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, and Simpson Gumpertz & Heger (SGH) calculation 148216-CA-021, "Seismic Response of the ONS Auxiliary Building Including SSI Effects," Revision 0, dated September 20, 2016, as a part of the audit process for Oconee. The staff notes that the calculations derive seismic input values for the Auxiliary building that were ultimately generated by the NRC-accepted GMRS. See conclusion below for details.

Deviation(s) or Deficiency(ies), and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • The licensee's derivation of the Auxiliary Building In-Structure Response Spectra (ISRS) was generated using input motions based on GMRS demands. The staff considers this as reasonable for the purposes of this calculation.

Structural Parameters:

II. Seismic Design of the SFP Structure The licensee:

  • Performed site-specific calculations to demonstrate that the limiting Yes SFP HCLPF capacity value is greater than the peak spectral acceleration of the site-specific GMRS.

Notes from the reviewer:

1. The NRC staff confirmed that the licensee followed the methodology described in the SFP Evaluation Guidance Report in Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, to calculate an SFP HCLPF capacity. The resulting HCLPF value of 1.39g is greater than the site-specific GMRS peak spectral acceleration of .869; therefore, it is reasonable to conclude that the SFP has sufficient capacity to withstand a seismic event at least up to the GMRS without failure that would lead to a rapid draindown.

Deviation(s) or Deficiency(ies), and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • The SFP has sufficient capacity to withstand a seismic event at least up to the GMRS without failure that would lead to a rapid draindown.

Ill. SFP Structure Included in the Civil Inspection Program Performed in Accordance with Maintenance Rule The licensee:

  • Stated that the SFP structure is included in the Civil Inspection Yes Program performed in accordance with Maintenance Rule ( 10 CFR 50.65).

Notes from the reviewer:

1. The licensee stated that the SFP structure is included in the Oconee Civil Inspection Program, Procedure AD-EG-ONS-1214, "Condition Monitoring of Structures,"

Revision 1". Updated Final Safety Analysis Report (UFSAR) Section 18.3.13, "Inspection Program for Civil Engineering Structures and Components," describes this program.

Deviation(s) or Deficiency(ies}, and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • The SFP structure is included in the Civil Inspection Program performed in accordance with Maintenance Rule (10 CFR 50.65).

Non-Structural Parameters:

IV. Applicability of Piping Evaluation The licensee:

  • Stated that there are no piping penetrations attached to the SFP Yes more than 6 feet (ft.) below the surface of the water and cited plant drawings (0-443 & 0-2443).

Notes from the reviewer:

1. The licensee stated that all SFP penetrations are located above the SFP normal water level.

Deviation{s) or Deficiency{ies}, and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • There are no piping penetrations attached to the SFP more than 6 ft. below the surface of the water.

V. Ductile Behavior of SFP Gates The licensee:

  • Stated that the SFP gate is constructed from a ductile material (e.g . No aluminum or stainless steel alloys).

Notes from the reviewer:

1. The Licensee stated that Oconee SFPs have fuel transfer tubes and not SFP gates.

The licensee also stated that the transfer tubes are sealed closed with a bolted steel flanged cover and are constructed from a stainless steel alloy. UFSAR Section 9.1.4.2 also states that during reactor operations, bolted and gasketed closure plates, located on the reactor building flanges of the fuel transfer tubes, isolate the fuel transfer canal from the spent fuel pool. Therefore, according to the SFP guidance, the fuel transfer tubes would not be a potential drain down path following an earthquake.

Deviation(s) or Deficiency(ies), and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • The SFP transfer tubes are constructed from a material expected to exhibit ductile behavior under higher seismic demands.

VI. Siphoning Evaluation The licensee:

  • Stated that anti-siphoning devices are installed on piping systems Yes that could lead to siphoning inventory from the SFP.
  • In cases where anti-siphoning devices were not included on the N/A applicable piping, a description documenting the evaluation performed to determine the seismic adequacy of the piping is provided.
  • Stated that the piping of the SFP cooling system cannot lead to rapid Yes drain down due to siphoning.
  • Stated that no anti-siphoning devices are attached to 2" or smaller Yes piping with extremely large extended operators.
  • Provided a seismic adequacy evaluation, in accordance with N/A NP-6041, for cases where active siphoning devices are attached to 2" or smaller piping with extremely large extended operators.

Notes from the reviewer:

1. The licensee stated that the fuel pool piping is arranged so that the pool cannot be inadvertently drained to uncover the fuel. The licensee referenced plant design document, "BDB [beyond-design basis] OSS-0254.00-00-1006," and described that either pipes do not extent more than four feet below the normal pool water level or siphon breakers are present in SFP-attached piping that could lead to siphoning of water.

Deviation(s) or Deficiency(ies), and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • Anti-siphoning devices exist in applicable piping systems that could Yes lead to siphoning water from the SFP.
  • Piping of the SFP cooling system is not likely to lead to rapid Yes draindown due to siphoning.
  • No active anti-siphoning devices are attached to 2" or smaller piping Yes with extremely large extended operators.

VII. Sloshing Evaluation The licensee:

  • Specified the SFP dimensions {length, width, and depth} . Yes
  • Specified that the SFP dimensions are bounded by the dimensions Yes specified in the report (i.e., SFP length and width <125 ft.; SFP depth >36 ft.).

Notes from the reviewer:

1. SFP dimensions (Units 1 & 2) (Oconee Site drawings 0-18C)

- SFP Length - 84 ft. 3 in.

- SFP Width - 24 ft.

- SFP Depth - 38 ft.

2. SFP dimensions (Unit 3) (Oconee Site drawings 0-2154-S).

- SFP Length - 58 ft.

- SFP Width - 24 ft.

- SFP Depth - 38 ft.

Deviation(s) or Deficiency(ies}, and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes that:

  • SFP dimensions are bounded by the dimensions specified in the Yes report (i.e., SFP length and width <125 ft.; SFP depth >36 ft.).

VIII. Evaporation Evaluation The licensee:

  • Provided the surface area of the plant's SFP . Yes
  • Stated that the surface area of the plant's SFP is greater than Yes 500 ft2
  • Provided the licensed reactor core thermal power. Yes Yes
  • Stated that the reactor core thermal power is less than 4,000 megawatt thermal (MW1) per unit.

Notes from the reviewer:

1. Surface area of pool (Unit 1 & 2) = 2022 ft2 (Oconee Site drawing 0-18C)
2. Surface area of pool (Unit 3) = 1392 ft 2 (Oconee Site Drawing 0-2154-S)
3. Reactor thermal power= 2568 MW1 (each Unit) (UFSAR Section 1.1)

Deviation(s) or Deficiency(ies), and Resolution:

No deviations or deficiencies were identified.

The NRC staff concludes:

  • The surface area of the plant's SFP is greater than 500 ft 2. Yes
  • The reactor core thermal power is less than 4,000 MW1 per unit. Yes

==

Conclusions:==

The NRC staff reviewed the licensee's SFP evaluation report. Based on its review, the NRC staff concludes that the SFP Evaluation Guidance Report methodology has been followed when calculating the site-specific seismic capacity of the SFP, and that Oconee's site-specific values and conditions are within the acceptable limits and bounds considered for the non-structural evaluation criteria specified in the SFP Evaluation Guidance Report. Therefore, the licensee responded appropriately to Item (9) in Enclosure 1 of the 50.54(f) letter. The NRC staff further concludes that the licensee has demonstrated an adequate margin to preclude a potential drain-down of the SFP as a result of the reevalutaed seismic hazard at Oconee.

AUDIT

SUMMARY

BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO OCONEE NUCLEAR STATION, UNITS 1, 2, AND 3 SPENT FUEL POOL EVALUATION ASSOCIATED WITH REEVALUATED SEISMIC HAZARD IMPLEMENTING NEAR-TERM TASK FORCE RECOMMENDATION 2.1: SEISMIC (EPID L-2017-JLD-0056)

BACKGROUND AND AUDIT BASIS By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340), the U.S. Nuclear Regulatory Commission (NRC) issued a request for information under Title 10 of the Code of Federal Regulations ( 10 CFR),

Section 50.54(f) (hereafter referred to as the 50.54(f) letter). Enclosure 1 to the 50.54(f) letter requested that licensees reevaluate the seismic hazards for their sites using present-day methods and regulatory guidance used by the NRC staff when reviewing applications for early site permits and combined licenses.

By letter dated October 27, 2015 {ADAMS Accession No. ML15194A015), the NRC made a determination of which licensees were to perform: (1) a seismic probabilistic risk assessment (SPRA), (2) limited scope evaluations, or (3) no further actions based on a comparison of the reevaluated seismic hazard and the site's design-basis earthquake. (Note: Some plant-specific changes regarding whether an SPRA was needed or limited scope evaluations were needed at certain sites have occurred since the issuance of the October 27, 2015, letter.)

By letter dated July 11, 2017 (ADAMS Accession No. ML17192A168), the NRC issued a generic audit plan to Oconee Nuclear Station, Units 1, 2, and 3 (Oconee) and entered into the audit process described in Office Instruction LIC-111, "Regulatory Audits," dated December 29, 2008 (ADAMS Accession No. ML082900195), to assist in the timely and efficient closure of activities associated with the 50.54(f) letter.

REGULATORY AUDIT SCOPE AND METHODOLOGY The areas of focus for the regulatory audit are the information contained in the spent fuel pool (SFP) evaluation submittal and all associated and relevant supporting documentation used in the development of the SFP evaluation including, but not limited to, methodology, process information, calculations, computer models, etc.

AUDIT ACTIVITIES The Oconee audit took place at the NRC Headquarters in Rockville, MD, beginning on July 14, 2018. Licensee personnel participated remotely, via email, from their respective offices. A list of the licensee staff and NRC staff that participated in the audit is contained in Table 1.

Enclosure 2

Table 1 NRC Staff Licensee Staff Name I Title Name I Title Frankie Vega I Project ManaQer Paul Guill I Sr. LicensinQ Engineer On June 14, 2018, the NRC staff requested, via email, that the licensee upload Jensen Hughes calculation No. 1 PJA25021-AQ-CAL-001, "ONS SFP Structural Calculation," Revision 0, dated October 27, 2017, which was the calculation that was performed to determine the high confidence low probability of failure (HCLPF) value for the SFP onto the licensee's ePortal (electronic reading room). In addition, the staff requested a series of plant drawings and procedures (detailed below) that were refereced as part of the SFP submmital. The licensee uploaded the requested documents onto the ePortal on June 25, 2018, as requested by the NRC staff.

DOCUMENTS AUDITED

  • AD-EG-ONS-1214, "Condition Monitoring of Structures," Revision O;
  • 0-443, "Piping Layout Plan and Sections - SF Pool - El. 844-0"-Auxiliary Building, Units 1 & 2";
  • 0-2443, "Piping Layout Plan and Sections - SF Pool - El. 844F-O"-Auxiliary Building, Unit 3;
  • OFD-104A-1.1, "Flow Diagram of Spent Fuel Cooling System, Units 1 & 2";
  • OFD-104A-3.11, "Flow Diagram of Spent Fuel Cooling System, Unit 3";
  • 0-18C, "General Arrangement Spent Fuel Pool Units 1 & 2 Plan and Sections";
  • 0-2154-S, "Spent Fuel Pool Plan and Sections, Unit 3;
  • OM-271-0235-001, "Transfer Tube Assy";
  • DBD OSS-0254.00-00-1006, "Desing Basis Specification for the Spent Fuel Pool Cooling System," Revision 23;
  • SGH Calculation 148216-CA-021, "Seismic Response of the ONS Auxiliary Building Including SSI Effects," Revision 0.

OPEN ITEMS AND REQUEST FOR INFORMATION Following the review of the SFP HCLPF calculation, there were no open items identified by the NRC staff that required proposed closure paths, and there were no requests for information discussed or planned to be issued.

DEVIATIONS FROM AUDIT PLAN There were no deviations from the July 11, 2017, generic audit plan.

AUDIT CONCLUSION The issuance of this document, containing the staff's review of the SFP evaluation submittal, concludes the SFP audit process for Oconee.

ML18197A201 *via e-mail OFFICE NRR/DLP/PBMB/PM NRR/DLP/PBMB/LA NRR/DLP/PBMB/BC (A)

NAME FVega SLent BTitus DATE 07/18/2018 07/16/2018 07/25/2018 OFFICE NRR/DLP/PBMB/PM NAME FVega DATE 07/25/2018

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