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| number = ML14101A445 | | number = ML14101A445 | ||
| issue date = 06/04/2014 | | issue date = 06/04/2014 | ||
| title = | | title = Staff Assessment of the Seismic Walkdown Report Supporting Implementation of Near-Term Task Force Recommendation 2.3 Related to the Fukushima Dai-Ichi Nuclear Power Plant Accident (Tac No. MF0095) | ||
| author name = Weibe J | | author name = Weibe J | ||
| author affiliation = NRC/NRR/DORL/LPLIII-2 | | author affiliation = NRC/NRR/DORL/LPLIII-2 | ||
| addressee name = Pacilio M | | addressee name = Pacilio M | ||
| addressee affiliation = Exelon Generation Co, LLC | | addressee affiliation = Exelon Generation Co, LLC | ||
| docket = 05000457 | | docket = 05000457 | ||
| license number = | | license number = | ||
| contact person = Weibe J | | contact person = Weibe J | ||
| case reference number = TAC MF0095 | | case reference number = TAC MF0095 | ||
| document type = Letter, Report, Miscellaneous | | document type = Letter, Report, Miscellaneous | ||
| page count = 12 | | page count = 12 | ||
| project = TAC:MF0095 | | project = TAC:MF0095 | ||
| stage = | | stage = Other | ||
}} | }} | ||
=Text= | =Text= | ||
{{#Wiki_filter: | {{#Wiki_filter:UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 4 , 2014 Mr. Michael J. Pacilio Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO) | ||
Exelon Nuclear 4300 Winfield Road Warrenville , IL 60555 | |||
==SUBJECT:== | ==SUBJECT:== | ||
BRAIDWOOD STATION , UNIT 2-STAFF ASSESSMENT OF THE SEISMIC WALKDOWN REPORT SUPPORTING IMPLEMENTATION OF NEAR-TERM TASK FORCE RECOMMENDATION | BRAIDWOOD STATION , UNIT 2 - STAFF ASSESSMENT OF THE SEISMIC WALKDOWN REPORT SUPPORTING IMPLEMENTATION OF NEAR-TERM TASK FORCE RECOMMENDATION 2.3 RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT (TAC NO. MF0095) | ||
== | ==Dear Mr. Pacilio:== | ||
On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request for information letter per Title 10 of the Code of Federal Regulations, Paragraph 50.54(f) (50.54(f) letter) . The 50.54(f) letter was issued to power reactor licensees and holders of construction permits requesting addressees to provide further information to support the NRC staff's evaluation of regulatory actions to be taken in response to lessons learned from Japan's March 11, 2011 , Great T6hoku Earthquake and subsequent tsunami. The request addressed the methods and procedures for nuclear power plant licensees to conduct seismic and flooding hazard walkdowns to identify and address degraded , nonconforming , or unanalyzed conditions through the corrective action program , and to verify the adequacy of the monitoring and maintenance procedures. | |||
On March 12 , 2012 , the U.S. Nuclear Regulatory Commission (NRC) issued a request for information letter per Title 10 of the Code of Federal Regulations, Paragraph 50.54(f) (50.54(f) letter). The 50.54(f) letter was issued to power reactor licensees and holders of construction permits requesting addressees to provide further information to support the NRC staff's evaluation of regulatory actions to be taken in response to lessons learned from Japan's March 11, 2011 , Great T6hoku Earthquake and subsequent tsunami. The request addressed the methods and procedures for nuclear power plant licensees to conduct seismic and flooding hazard walkdowns to identify and address degraded , nonconforming , or unanalyzed conditions through the corrective action program , and to verify the adequacy of the monitoring and maintenance procedures. By letter dated November 27 , 2012 , as supplemented by letters dated January 6, 2014, and March 31 , 2014 , Exelon Generation Company (Exelon) submitted its Seismic Walkdown Report as requested in Enclosure 3 of the 50.54(f) letter for the Braidwood Station, Unit 2. By letter dated November 27 , 2013 , Exelon provided a response to the NRC request for additional information for the staff to complete its assessments. The NRC staff reviewed the information provided and , as documented in the enclosed staff assessment , determined that sufficient information was provided to be responsive to Enclosure 3 of the 50.54(f) letter. | By letter dated November 27, 2012, as supplemented by letters dated January 6, 2014, and March 31 , 2014, Exelon Generation Company (Exelon) submitted its Seismic Walkdown Report as requested in Enclosure 3 of the 50.54(f) letter for the Braidwood Station, Unit 2. By letter dated November 27, 2013, Exelon provided a response to the NRC request for additional information for the staff to complete its assessments. | ||
M. Pacilio If you have any questions , please contact me at 301-415-6606 or by e-mail at Joei.Wiebe@nrc.gov. Docket No. 50-456 | The NRC staff reviewed the information provided and, as documented in the enclosed staff assessment, determined that sufficient information was provided to be responsive to Enclosure 3 of the 50.54(f) letter. | ||
M. Pacilio If you have any questions, please contact me at 301-415-6606 or by e-mail at Joei .Wiebe@nrc.gov. | |||
Sincerely, oel S. Wiebe, Senior Project Manager Plant Licensing 111-2 and Planning and Analysis Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-456 | |||
==Enclosure:== | ==Enclosure:== | ||
Staff Assessment of Seismic Walkdown Report cc w/encl : Distribution via Listserv | |||
TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT | |||
STAFF ASSESSMENT OF SEISMIC WALKDOWN REPORT NEAR-TERM TASK FORCE RECOMMENDATION 2.3 RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT EXELON GENERATION COMPANY, LLC BRAIDWOOD STATION, UNIT 2 DOCKET NO. 050-457 | |||
==1.0 INTRODUCTION== | |||
On March 12, 2012,1 the U.S. Nuclear Regulatory Commission (NRC) issued a request for information per Title 10 of the Code of Federal Regulations (1 0 CFR) , Paragraph 50.54(f) | |||
(50.54(f) letter) , to all power reactor licensees and holders of construction permits in active or deferred status. The request was part of the implementation of lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 3, "Recommendation 2.3: | |||
Seismic," 2 to the 50.54(f) letter requested licensees to conduct seismic walkdowns to identify and address degraded , nonconforming, or unanalyzed conditions using the corrective action program (CAP) , verify the adequacy of monitoring and maintenance procedures, and report the results to the NRC. | |||
The 50.54(f) letter requested licensees to provide the following : | |||
: a. Information concerning the plant-specific hazard licensing bases and a description of the protection and mitigation features considered in the licensing basis evaluation . | |||
: b. Information related to the implementation of the walkdown process. | |||
: c. A list of plant-specific vulnerabilities identified by the Individual Plant Examination of External Events (IPEEE) program and a description of the actions taken to eliminate or reduce them . | |||
: d. Results of the walkdown including key find ings and identified degraded , | |||
nonconforming , or unanalyzed conditions. | |||
: e. Any planned or newly installed protectiQn and mitigation features . | |||
: f. Results and any subsequent actions taken in response to the peer review. | |||
In accordance with the 50.54(f) letter, Enclosure 3, Required Response Item 2, licensees were required to submit a response within 180 days of the NRC's endorsement of the seismic 1 | |||
Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340 2 | |||
ADAMS Accession No. ML12056A049 Enclosure | |||
walkdown process. By letter dated May 29, 2012, 3 the Nuclear Energy Institute submitted Electric Power Research Institute document 1025286, "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, " (walkdown guidance) to the NRC staff to consider for endorsement. By letter dated May 31 , 2012 ,4 the NRC staff endorsed the walkdown guidance. | |||
By letter dated November 27, 2012, 5 Exelon Generation Company, LLC (the licensee) provided a response to Enclosure 3 of the 50.54(f) letter Required Response Item 2, for Braidwood Station (Braidwood) , Unit 2. In addition to the aforementioned letter, the licensee by letter dated January 6, 20146 , provided an update to the initial seismic walkdown report. The purpose of the latter submittal was to update and provide information on inaccessible components and supplemtal cabinet inspections not completed in the first submittal. The licensee, by letter dated March 31 , 20147 , updated the seismic walkdown report to include several walkdown results not provided as part of the January 6, 2014 update. | |||
The NRC staff reviewed the walkdown report and determined that additional supplemental information would assist the staff in completing its review. In a letter dated November 1, 20138 , | |||
the NRC staff requested additional information to gain a better understanding of the processes and procedures used by the licensee in conducting the walkdowns and walk-bys . The licensee responded to the NRC staff request by letter dated November 27, 2013.9 The NRC staff evaluated the licensee's submittals to determine if the information provided in the walkdown report met the intent of the walkdown guidance, and if the licensee responded appropriately to Enclosure 3 of the 50.54(f) letter. | |||
==2.0 REGULATORY EVALUATION== | |||
The structures, systems, and components (SSCs) important to safety in operating nuclear power plants are designed either in accordance with , or meet the intent of, Appendix A to 10 CFR Part 50, General Design Criteria (GDC) 2: "Design Bases for Protection Against Natural Phenomena; " and Appendix A to 10 CFR Part 100, "Reactor Site Criteria. " GDC 2 states that SSCs important to safety at nuclear power plants 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 . | |||
For initial licensing, each licensee was required to develop and maintain design bases that, as defined by 10 CFR 50.2, identify the specific functions that an SSC of a facility must perform, and the specific values or ranges of values chosen for controlling parameters as reference bounds for the design . | |||
3 ADAMS Package Accession No. ML121640872 4 | |||
ADAMS Accession No. ML12145A529 5 | |||
ADAMS Package Accession No. ML123390284 6 | |||
ADAMS Package Accession No. ML14016A021 7 | |||
ADAMS Package Accession No. ML14119A375 8 | |||
ADAMS Package Accession No. ML14119A375 9 | |||
ADAMS Accession No. ML133318501 | |||
The design bases for the SSCs reflect appropriate consideration of the most severe natural phenomena that have been historically reported for the site and surrounding area. The design bases also reflect sufficient margin to account for the limited accuracy, quantity, and period of time in which the historical data have been accumulated. | |||
The current licensing basis is the set of NRC requirements applicable to a specific plant, including the licensee's docketed commitments for ensuring compliance with , and operation within , | |||
applicable NRC requirements and the plant-specific design basis, including all modifications and additions to such commitments over the life of the facility operating license. | |||
===3.1 Seismic | ==3.0 TECHNICAL EVALUATION== | ||
Licensing Basis Information The licensee | |||
The staff reviewed Section 2 of the walkdown report , focusing on the summary of the SSE and the design codes used in the design. Based on the NRC staff's review , the staff concludes that the licensee has provided information on the plant-specific seismic licensing basis and a description of the protection and mitigation features considered in the licensing bases evaluation consistent with Section 8 , Submittal Report , of the walkdown guidance. 3.2 Seismic Walkdown Methodology Implementation Section 2 , Personnel Qualifications | 3.1 Seismic Licensing Basis Information The licensee provided information on the plant-specific licensing basis for the Seismic Category I SSCs for Braidwood , Unit 2, in Section 2 of the walkdown report. Consistent with the walkdown guidance, the NRC staff noted that the report includes a summary of the safe-shutdown earthquake (SSE) and a description of the codes , standards, and methods that were used in the design of the Seismic Category I SSCs for meeting the plant-specific seismic licensing basis requirements. The staff reviewed Section 2 of the walkdown report, focusing on the summary of the SSE and the design codes used in the design. | ||
; Section 3 , Selection of SSCs; Section 4 , Seismic Walkdowns and Area Walk-Bys; and Section 5, Seismic Licensing Basis Evaluations , of the walkdown guidance provide information to licensees regarding the implementation of an appropriate seismic walkdown methodology. By letter dated July 10 , 2012, | Based on the NRC staff's review, the staff concludes that the licensee has provided information on the plant-specific seismic licensing basis and a description of the protection and mitigation features considered in the licensing bases evaluation consistent with Section 8, Submittal Report, of the walkdown guidance. | ||
The NRC staff reviewed the | 3.2 Seismic Walkdown Methodology Implementation Section 2, Personnel Qualifications; Section 3, Selection of SSCs; Section 4, Seismic Walkdowns and Area Walk-Bys ; and Section 5, Seismic Licensing Basis Evaluations, of the walkdown guidance provide information to licensees regarding the implementation of an appropriate seismic walkdown methodology. By letter dated July 10, 2012, 10 the licensee confirmed that it would use the walkdown guidance in the performance of the seismic walkdowns at Braidwood, Unit 2. | ||
The walkdown report dated November 27, 2012, and updated on January 6, 2014, and March 31, 2014, did not identify deviations from the walkdown guidance. | |||
The NRC staff reviewed the following sections of the walkdown methodology implementation provided in the walkdown report: | |||
* Personnel Qualifications | * Personnel Qualifications | ||
* Development of the | * Development of the Seismic Walkdown Equipment Lists (SWELs) | ||
* Implementation of the Walkdown Process | * Implementation of the Walkdown Process | ||
* Licensing Basis Evaluations and Results 10 ADAMS Accession No. | * Licensing Basis Evaluations and Results 10 ADAMS Accession No. ML12193A081 | ||
3.2.1 Personnel Qualifications Section 2, Personnel Qualifications, of the walkdown guidance provides licensees with qualification information for personnel involved in the conduct of the seismic walkdowns and area walk-bys. | |||
The NRC staff reviewed the information provided in Section 3 and Appendix A of the walkdown report, which includes information on the walkdown personnel and their qualifications. | |||
Specifically, the staff reviewed the summary of the background, experience, and level of involvement for the following personnel involved in the seismic walkdown activities: equipment selection personnel, seismic walkdown engineers (SWEs), licensing basis reviewers, IPEEE reviewers, peer review team , and operations staff. | |||
Based on the review of the licensee's submittals, the NRC staff concludes that those involved in the seismic walkdown activities have the appropriate seismic background, knowledge and experience, as specified in Section 2 of the walkdown guidance. | |||
3.2.2 Development of the SWELs Section 3, Selection of SSCs, of the walkdown guidance provides information to licensees for selecting the SSCs that should be placed on the SWELs, so that they can be walked down by qualified personnel. | |||
The NRC staff reviewed the overall process used by the licensee to develop the Braidwood, Unit 2, base list, SWEL 1 (sample list of designated safety functions equipment), and SWEL 2 (sample list of spent fuel pool (SFP)-related equipment). The licensee stated that the process for selecting a sample of SSCs for safe shutting down the reactor and maintaining containment integrity began with IPEEE Success Path Equipment List (SPEL) . The IPEEE SPEL was then subjected to the screening process provided by the walkdown guidance to identify items to be included in SWEL 1. | |||
The licensee provided the SWEL 1 for Braidwood, Unit 2, in Appendix B, Table B-3, of the walkdown report and discussed this list in Section 4.2 of the walkdown report. The SWEL 2 items are listed in Table B-4. | |||
The overall equipment selection process followed the screening process shown in Figures 1-1 and 1-2 of the walkdown guidance as discussed above. Based on Appendix B of the walkdown report, Braidwood, Unit 2, SWELs 1 and 2, meets the inclusion requirements of the walkdown guidance. Specifically, the following attributes were considered in the sample selection: | |||
* A variety of systems, equipment and environments, | |||
* IPEEE equipment, | |||
* Major new or replacement equipment, and | |||
* Risk considerations. | |||
It is possible that some classes of equipment will not be represented on the SWEL due to individual plant configurations , and the walkdown guidance screening process followed to select the final SWEL equipment. The walkdown guidance recognizes this is due to the equipment not | |||
being present in the plant (e.g ., some plants generate direct current power using inverters and, therefore , do not have motor generators) or the equipment being screened out during the screening process (the screening process is described in Section 3 of the walkdown guidance). | |||
Based on the information provided , the NRC staff noted that a detailed explanation was provided justifying cases where specific classes of equipment were not included as part of the SWEL and concludes that these exclusions are acceptable. | |||
The NRC staff noted that a rapid drain-down list was not included as part of the SWEL 2, as described in Section 3 of the guidance. In Section 4.2.2.4 of the walkdown report, the licensee stated there are no components that could, upon failure , result in rapid drain-down of the SFP water level to below 3 meters (1 0 feet) above the top of the fuel. After reviewing the information provided in this section, the staff concludes that the licensee provided adequate justification for not including rapid drain-down items as part of the SWEL 2. | |||
After reviewing the SWEL, the NRC staff concludes that the sample of SSCs represents a diversity of component types and assures inclusion of components from critical systems and functions, thereby, meeting the intent of the walkdown guidance. In addition, the NRC staff notes that the equipment selection personnel were appropriately supported by plant operations staff as described in the walkdown guidance. | |||
3.2.3 Implementation of the Walkdown Process Section 4, Seismic Walkdowns and Area Walk-Bys, of the walkdown guidance provides information to licensees regarding the conduct of the seismic walkdowns and area walk-bys for each site. | |||
The NRC staff reviewed Section 5 of the walkdown report, which summarizes the results of the seismic walkdowns and area walk-bys, including an overview of the number of items walked down and the number of areas walked-by. The walkdown report states that teams, which consisted of two trained SWEs, conducted the seismic walkdowns and area walk-bys. According to the signed seismic walkdown checklists (SWCs) and area walk-by checklists (AWCs), these activities were conducted during the week of July 30, 2012. In addition , a subsequent set of walkdowns were performed by the end of 2012, and throughout 2013, as referred to in the January 6, 2014, letter, from the licensee. The purpose of the last activity was to complete a number of items that were inaccessible during the initial walkdowns and to complete internal inspections on electrical cabinets. Several of the walkdown results were provided as part of this update. The complete set of walkdown results were provided as part of the second update submitted to the NRC on March 31 , 2014. | |||
The walkdown report also states that the SWEs discussed their observations and judgments with each other during the walkdowns . Additionally, the SWEs agreed on the results of their seismic walkdowns and area walk-bys before reporting the results of their review. Appendices C and 0 of the initial walkdown report, Appendices AC and AD of Annex A, and Appendices BC and BD of Annex B of the updated report, provide the completed SWCs and AWCs, documenting the results for each item of equipment on the SWELs and each area containing SWEL equipment. The licensee used the checklists provided in Appendix C of the walkdown guidance report without modification. | |||
The NRC staff noted that a rapid drain-down list was not | |||
In addition, the NRC staff notes that the equipment selection personnel were appropriately supported by plant operations staff as described in the walkdown guidance. | |||
The licensee documented cases of potentially adverse seismic conditions (PASCs) in the checklists for further evaluation . The licensee stated that none of the issues identified during the walkdowns were ultimately judged to be PASCs. Tables 5-2 and 5-3 of the walkdown report list the conditions identified during the initial seismic walkdowns and the area walk-bys. Tables A5-2 , A5-3 , B5-2 and B5-3 of the updated report list the PASCs identified during the subsequent walkdowns . The tables describe how each condition was addressed (e.g., placement in the CAP) , its resolution and current status. | |||
Based on the initial review of the checklists, the NRC staff was unable to confirm that all the PASCs identified during the walkdowns were included in this table. By letter dated November 1, 2013, the staff issued two questions in a request for additional information (RAI) in order to obtain additional clarification regarding the process followed by the licensee when evaluating conditions identified in the field during the walkdowns and walk-bys. Specifically, in RAI 1, the staff requested the licensee to provide further explanation regarding how a field observation was determined to be PASC, and to ensure that the basis for determination was addressed using normal plant processes and documented in the walkdown report. In response to RAI 1, the licensee confirmed that all conditions identified during the walkdowns and walk-bys were documented as issue reports (IRs) in the Braidwood, Unit 2, CAP. The licensee referred to Tables 5-2 and 5-3 of the initial walkdown report and Tables A5-2, A5-3, B5-2 and B5-3 of the updated walkdown reports , which include the IRs identified during the walkdowns and area walk-bys for Braidwood , Unit 2. In addition, the licensee stated that all identified nonseismic potentially adverse conditions , such as housekeeping and material conditions items, were identified by SWEs and addressed through the CAP. Furthermore, the licensee confirmed that, based on its review of Braidwood, Unit 2, walkdown process and the information submitted in the walkdown report, that no new conditions were identified that would require an additional supplement or additional CAP entries. | |||
After evaluating the licensee's response and reviewing summary Tables 5-2, 5-3, A5-2 , A5-3, B5-2 and B5-3 of the walkdown reports, the NRC staff concludes that the licensee responded appropriately to RAI 1. In addition, the staff concludes that conditions, including any PASCs, were properly identified and documented, and the summary tables provided are considered complete. | |||
In addition to the information provided above, the NRC staff notes that anchorage configurations were verified to be consistent with existing plant documentation for at least 50 percent of the SWEL items, in accordance with Section 4 of the walkdown guidance. | |||
Tables E-1 and E-2 of the initial walkdown report, list equipment and areas that were inaccessible during the 180-day period. Table E-1 lists 18 SWEL components that were inaccessible at the time of the walkdowns due to a required outage, its respective completion date, and status. | |||
Table E-2 lists those cabinets that were not internally inspected during the initial walkdowns. | |||
Items identified in Tables E-1 and E-2 were walked down by the end of 2012, and during 2013, before the Spring 2014, comm itment. As confirmed by the January 6, 2014, letter, from the licensee, walkdown results were provided for most of these items. The walkdown results for several internal cabinet inspections were submitted to the NRC. As part of the March 31 , 2014, submittal. | |||
Based on the information provided in the licensee's submittals, the NRC staff concludes that the licensee's implementation of the walkdown process meets the intent of the walkdown guidance. | |||
3.2.4 Licensing Basis Evaluations and Results Section 5, Seismic Licensing Basis Evaluations, of the walkdown guidance provides information to licensees regarding the conduct of licensing basis evaluations for items identified during the seismic walkdowns as degraded , nonconforming, or unanalyzed that might have potential seismic significance. | |||
The NRC staff reviewed Section 6 of the Braidwood , Unit 2, walkdown report which discusses the process for conducting the seismic licensing basis evaluations of the PASCs identified during the seismic walkdowns and area walk-bys. The licensee stated that it performed licensing basis evaluations and resolved PASCs using the plant's CAP. Tables 5-2 and 5-3 of the intial walkdown report, and Tables A5-2, A5-3, B5-2 and B5-3 of the updated walkdown report, list the key licensee findings, and provide a complete list of the potentially degraded , nonconforming , or unanalyzed conditions . These tables also describe the actions taken or planned to address these conditions, including the current status of each of the items the licensee entered into the CAP. | |||
The NRC staff reviewed the CAP entries and the description of the actions taken or planned to address potential deficiencies. The staff concludes that the licensee appropriately identified degraded , nonconforming, or unanalyzed conditions and entered them into the CAP, which meets the intent of the walkdown guidance. | |||
3.2.5 Conclusion Based on the discussion above, the NRC staff concludes that the licensee's implementation of seismic walkdown methodology meets the intent of the walkdown guidance for personnel qualifications, development of SWELs, implementation of the walkdown process, and seismic licensing basis evaluations. | |||
The licensee stated that it performed licensing basis evaluations and resolved PASCs using the plant's CAP. Tables 5-2 and 5-3 of the intial walkdown report, and Tables A5-2, A5-3 , B5-2 and B5-3 of the updated walkdown report , list the key licensee findings , and provide a complete list of the potentially degraded , nonconforming , or unanalyzed conditions. These tables also describe the actions taken or planned to address these conditions, including the current status of each of the items the licensee entered into the CAP. The NRC staff reviewed the CAP | 3.3 Peer Review Section 6, Peer Review, of the walkdown guidance provides licensees with information regarding the conduct of peer reviews for the activities performed during the seismic walkdowns . Page 6-1 of the walkdown guidance identifies the following activities to be conducted during the peer review process: | ||
* Review the selection of the SSCs included on the SWELs. | |||
Based on the discussion above , the NRC staff concludes that the | |||
* Review the | |||
* Review a sample of the checklists prepared for the seismic walkdowns and area walk-bys. | * Review a sample of the checklists prepared for the seismic walkdowns and area walk-bys. | ||
* Review the licensing basis | * Review the licensing basis evaluations. | ||
* Review the decisions fo r entering the potentially adverse conditions into the CAP. | * Review the decisions fo r entering the potentially adverse conditions into the CAP. | ||
* | * Review the walkdown report. | ||
* Summarize the | * Summarize the results of the peer review process in the walkdown report. | ||
The NRC staff reviewed the information provided in Section 8 of the Braidwood , Unit 2, walkdown report which describes the conduct of the peer review. In addition, the staff reviewed the response to RAI 2. In RAI 2, the staff requested the licensee to provide additional information on the overall peer review process that was followed as part of the walkdown activities. Specifically, the staff requested the licensee to confirm that the activities identified on page 6-1 of the walkdown guidance were assessed and documented in the report. The licensee was also requested to confirm that any individual involved in performing any given walkdown activity was not a peer reviewer for that same activity. In response to RAI 2, the licensee confirmed that all the activities identified on page 6-1 of the walkdown guidance were included as part of the peer-review process, and referred to the summary of the peer review activities provided in Section 8, and the full-peer review report in Appendix F of the walkdown report. In addition, the licensee stated that there were no cases where any peer reviewer reviewed their own work. | |||
The NRC staff reviewed the licensee's summary of each of these activities, which included a discussion of the peer review team members' qualifications and level of involvement, the peer review findings, and resolution of peer review comments. After reviewing the licensee's submittals, the NRC staff concludes that the licensee sufficiently documented the results of the peer review activities and how these reviews affected the work described in the walkdown report. | |||
Based on the discussion above, the NRC staff concludes that the licensee's results of the peer review and subsequent actions taken in response to the peer review meets the intent of Section 6 of the walkdown guidance. | |||
3.4 IPEEE Information Section 7, IPEEE Vulnerabilities , of the walkdown guidance provides information to licensees regarding the reporting of the evaluations conducted and actions taken in response to seismic vulnerabilities identified during the IPEEE program . Through the IPEEE program and Generic Letter 88-20, "Individual Plant Examination of External Events for Severe Accident Vulnerabilities ," licensees previously had performed a systematic examination to identify any plant-specific vulnerabilities to severe accidents. | |||
The licensee provided background information regarding their IPEEE program and referenced several submittals to the NRC . The licensee stated that no vulnerabilities were reported in the previous IPEEE reports. However, a few plant improvements were identified in Appendix G. | |||
Table G-1 lists the improvements, the IPEEE-proposed resolution, the actual resolution and the resolution date. All IPEEE plant improvements and associated actions are complete. | |||
Based on the NRC staff's review of Section 7 of the walkdown report, the staff concludes that the licensee's summary of the IPEEE is consistent with and meets the intent of Section 7 of the walkdown guidance. | |||
3.5 Planned Upgrades The licensee did not identify any planned or newly installed protection and mitigation features in the walkdown report. | |||
Verification by Resident Inspectors On July 6 , 2012 , 10 the NRC issued Temporary Instruction (TI) 2515/188 "Inspection of Near-Term Task Force Recommendation | 3.6 NRC Oversight 3.6.1 Independent Verification by Resident Inspectors On July 6, 2012,10 the NRC issued Temporary Instruction (TI) 2515/188 "Inspection of Near-Term Task Force Recommendation 2.3 Seismic Walkdowns. " In accordance with the Tl, NRC inspectors independently verified that Braidwood, Unit 2, licensee implemented the seism ic walkdowns in accordance with the walkdown guidance. Additionally, the inspectors independently performed walkdowns of a sample of seismic protection features. The inspection report dated February 7, 2013,11 documents the results of this inspection and stated that no findings were identified. | ||
== | ==4.0 CONCLUSION== | ||
The NRC staff concludes that the licensee's implementation of seismic walkdown methodology meets the intent of the walkdown guidance. The staff concludes that the licensee, through the implementation of the walkdown guidance activities, and in accordance with plant processes and procedures, verified the plant configuration with the current seismic licensing basis; addressed degraded , nonconforming , or unanalyzed seism ic conditions ; and verified the adequacy of monitoring and maintenance programs for protective features . Furthermore, the staff notes that no immediate safety concerns were identified. The NRC staff reviewed the information provided and determined that sufficient information was provided to be responsive to Enclosure 3 of the 50.54(f) letter. | |||
10 ADAMS Accession No. ML 121.56A052 11 ADAMS Accession No. ML13038A635 | |||
If you have any questions, please contact me at 301-415-6606 or by e-mail at Joei .Wiebe@nrc.gov. | |||
Sincerely, IRA! | |||
Joel S. Wiebe, Senior Project Manager Plant Licensing 111-2 and Planning and Analysis Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-457 | |||
==Enclosure:== | ==Enclosure:== | ||
Staff Assessment of Seismic Walkdown Report cc w/encl : Distribution via Listserv DISTRIBUTION : | |||
* b | PUBLIC RidsOgcMaiiCenter Resource RidsRgn3MaiiCenter Resource LPL3-2 R/F RidsOpaMail Resource BRini , EDO Rl, Rll , Rill, RIV RidsNroDsea RidsNrrLASRohrer Resource RidsAcrsAcnw MaiiCTR Resource RidsNrrDorl Resource RidsNrrPMBraidwood Resource RidsNrrDorllpl3-2 Resource LRegner, NRR NChokshi, NRO SFianders, NRO DJackson, NRO RKaras , NRO FVega , NRO MJardaneh, NRO NDiFrancesco, NRR ADAMS A ccess1on N um ber: ML14101A445 | ||
*DATE 6/2/14 6/4/14 6/3/14 4/ 3 /2014 OFFICE DORLILPL3-2/BC DORLILPL3-2/PM NAME TTate JWiebe DATE 6/4/14 6/4/14 OFFICIAL RECORD COPY}} | * concurrence b)y e-ma1 OFFICE DORL/LP3-2/PM JLD/PMB/PM DORLILPL3-2/LA DSEA/RGS2 NAME JWiebe NDifrancesco SRohrer DJackson* | ||
*DATE 6/2/14 6/4/14 6/3/14 4/ 3 /2014 OFFICE DORLILPL3-2/BC DORLILPL3-2/PM NAME TTate JWiebe DATE 6/4/14 6/4/14 OFFICIAL RECORD COPY}} |
Latest revision as of 05:49, 4 November 2019
ML14101A445 | |
Person / Time | |
---|---|
Site: | Braidwood |
Issue date: | 06/04/2014 |
From: | Weibe J Plant Licensing Branch III |
To: | Pacilio M Exelon Generation Co |
Weibe J | |
References | |
TAC MF0095 | |
Download: ML14101A445 (12) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 June 4 , 2014 Mr. Michael J. Pacilio Senior Vice President Exelon Generation Company, LLC President and Chief Nuclear Officer (CNO)
Exelon Nuclear 4300 Winfield Road Warrenville , IL 60555
SUBJECT:
BRAIDWOOD STATION , UNIT 2 - STAFF ASSESSMENT OF THE SEISMIC WALKDOWN REPORT SUPPORTING IMPLEMENTATION OF NEAR-TERM TASK FORCE RECOMMENDATION 2.3 RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT (TAC NO. MF0095)
Dear Mr. Pacilio:
On March 12, 2012, the U.S. Nuclear Regulatory Commission (NRC) issued a request for information letter per Title 10 of the Code of Federal Regulations, Paragraph 50.54(f) (50.54(f) letter) . The 50.54(f) letter was issued to power reactor licensees and holders of construction permits requesting addressees to provide further information to support the NRC staff's evaluation of regulatory actions to be taken in response to lessons learned from Japan's March 11, 2011 , Great T6hoku Earthquake and subsequent tsunami. The request addressed the methods and procedures for nuclear power plant licensees to conduct seismic and flooding hazard walkdowns to identify and address degraded , nonconforming , or unanalyzed conditions through the corrective action program , and to verify the adequacy of the monitoring and maintenance procedures.
By letter dated November 27, 2012, as supplemented by letters dated January 6, 2014, and March 31 , 2014, Exelon Generation Company (Exelon) submitted its Seismic Walkdown Report as requested in Enclosure 3 of the 50.54(f) letter for the Braidwood Station, Unit 2. By letter dated November 27, 2013, Exelon provided a response to the NRC request for additional information for the staff to complete its assessments.
The NRC staff reviewed the information provided and, as documented in the enclosed staff assessment, determined that sufficient information was provided to be responsive to Enclosure 3 of the 50.54(f) letter.
M. Pacilio If you have any questions, please contact me at 301-415-6606 or by e-mail at Joei .Wiebe@nrc.gov.
Sincerely, oel S. Wiebe, Senior Project Manager Plant Licensing 111-2 and Planning and Analysis Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-456
Enclosure:
Staff Assessment of Seismic Walkdown Report cc w/encl : Distribution via Listserv
STAFF ASSESSMENT OF SEISMIC WALKDOWN REPORT NEAR-TERM TASK FORCE RECOMMENDATION 2.3 RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT EXELON GENERATION COMPANY, LLC BRAIDWOOD STATION, UNIT 2 DOCKET NO. 050-457
1.0 INTRODUCTION
On March 12, 2012,1 the U.S. Nuclear Regulatory Commission (NRC) issued a request for information per Title 10 of the Code of Federal Regulations (1 0 CFR) , Paragraph 50.54(f)
(50.54(f) letter) , to all power reactor licensees and holders of construction permits in active or deferred status. The request was part of the implementation of lessons learned from the accident at the Fukushima Dai-ichi nuclear power plant. Enclosure 3, "Recommendation 2.3:
Seismic," 2 to the 50.54(f) letter requested licensees to conduct seismic walkdowns to identify and address degraded , nonconforming, or unanalyzed conditions using the corrective action program (CAP) , verify the adequacy of monitoring and maintenance procedures, and report the results to the NRC.
The 50.54(f) letter requested licensees to provide the following :
- a. Information concerning the plant-specific hazard licensing bases and a description of the protection and mitigation features considered in the licensing basis evaluation .
- b. Information related to the implementation of the walkdown process.
- c. A list of plant-specific vulnerabilities identified by the Individual Plant Examination of External Events (IPEEE) program and a description of the actions taken to eliminate or reduce them .
- d. Results of the walkdown including key find ings and identified degraded ,
nonconforming , or unanalyzed conditions.
- e. Any planned or newly installed protectiQn and mitigation features .
- f. Results and any subsequent actions taken in response to the peer review.
In accordance with the 50.54(f) letter, Enclosure 3, Required Response Item 2, licensees were required to submit a response within 180 days of the NRC's endorsement of the seismic 1
Agencywide Documents Access and Management System (ADAMS) Accession No. ML12053A340 2
ADAMS Accession No. ML12056A049 Enclosure
walkdown process. By letter dated May 29, 2012, 3 the Nuclear Energy Institute submitted Electric Power Research Institute document 1025286, "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, " (walkdown guidance) to the NRC staff to consider for endorsement. By letter dated May 31 , 2012 ,4 the NRC staff endorsed the walkdown guidance.
By letter dated November 27, 2012, 5 Exelon Generation Company, LLC (the licensee) provided a response to Enclosure 3 of the 50.54(f) letter Required Response Item 2, for Braidwood Station (Braidwood) , Unit 2. In addition to the aforementioned letter, the licensee by letter dated January 6, 20146 , provided an update to the initial seismic walkdown report. The purpose of the latter submittal was to update and provide information on inaccessible components and supplemtal cabinet inspections not completed in the first submittal. The licensee, by letter dated March 31 , 20147 , updated the seismic walkdown report to include several walkdown results not provided as part of the January 6, 2014 update.
The NRC staff reviewed the walkdown report and determined that additional supplemental information would assist the staff in completing its review. In a letter dated November 1, 20138 ,
the NRC staff requested additional information to gain a better understanding of the processes and procedures used by the licensee in conducting the walkdowns and walk-bys . The licensee responded to the NRC staff request by letter dated November 27, 2013.9 The NRC staff evaluated the licensee's submittals to determine if the information provided in the walkdown report met the intent of the walkdown guidance, and if the licensee responded appropriately to Enclosure 3 of the 50.54(f) letter.
2.0 REGULATORY EVALUATION
The structures, systems, and components (SSCs) important to safety in operating nuclear power plants are designed either in accordance with , or meet the intent of, Appendix A to 10 CFR Part 50, General Design Criteria (GDC) 2: "Design Bases for Protection Against Natural Phenomena; " and Appendix A to 10 CFR Part 100, "Reactor Site Criteria. " GDC 2 states that SSCs important to safety at nuclear power plants 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 .
For initial licensing, each licensee was required to develop and maintain design bases that, as defined by 10 CFR 50.2, identify the specific functions that an SSC of a facility must perform, and the specific values or ranges of values chosen for controlling parameters as reference bounds for the design .
3 ADAMS Package Accession No. ML121640872 4
ADAMS Accession No. ML12145A529 5
ADAMS Package Accession No. ML123390284 6
ADAMS Package Accession No. ML14016A021 7
ADAMS Package Accession No. ML14119A375 8
ADAMS Package Accession No. ML14119A375 9
ADAMS Accession No. ML133318501
The design bases for the SSCs reflect appropriate consideration of the most severe natural phenomena that have been historically reported for the site and surrounding area. The design bases also reflect sufficient margin to account for the limited accuracy, quantity, and period of time in which the historical data have been accumulated.
The current licensing basis is the set of NRC requirements applicable to a specific plant, including the licensee's docketed commitments for ensuring compliance with , and operation within ,
applicable NRC requirements and the plant-specific design basis, including all modifications and additions to such commitments over the life of the facility operating license.
3.0 TECHNICAL EVALUATION
3.1 Seismic Licensing Basis Information The licensee provided information on the plant-specific licensing basis for the Seismic Category I SSCs for Braidwood , Unit 2, in Section 2 of the walkdown report. Consistent with the walkdown guidance, the NRC staff noted that the report includes a summary of the safe-shutdown earthquake (SSE) and a description of the codes , standards, and methods that were used in the design of the Seismic Category I SSCs for meeting the plant-specific seismic licensing basis requirements. The staff reviewed Section 2 of the walkdown report, focusing on the summary of the SSE and the design codes used in the design.
Based on the NRC staff's review, the staff concludes that the licensee has provided information on the plant-specific seismic licensing basis and a description of the protection and mitigation features considered in the licensing bases evaluation consistent with Section 8, Submittal Report, of the walkdown guidance.
3.2 Seismic Walkdown Methodology Implementation Section 2, Personnel Qualifications; Section 3, Selection of SSCs; Section 4, Seismic Walkdowns and Area Walk-Bys ; and Section 5, Seismic Licensing Basis Evaluations, of the walkdown guidance provide information to licensees regarding the implementation of an appropriate seismic walkdown methodology. By letter dated July 10, 2012, 10 the licensee confirmed that it would use the walkdown guidance in the performance of the seismic walkdowns at Braidwood, Unit 2.
The walkdown report dated November 27, 2012, and updated on January 6, 2014, and March 31, 2014, did not identify deviations from the walkdown guidance.
The NRC staff reviewed the following sections of the walkdown methodology implementation provided in the walkdown report:
- Personnel Qualifications
- Development of the Seismic Walkdown Equipment Lists (SWELs)
- Implementation of the Walkdown Process
- Licensing Basis Evaluations and Results 10 ADAMS Accession No. ML12193A081
3.2.1 Personnel Qualifications Section 2, Personnel Qualifications, of the walkdown guidance provides licensees with qualification information for personnel involved in the conduct of the seismic walkdowns and area walk-bys.
The NRC staff reviewed the information provided in Section 3 and Appendix A of the walkdown report, which includes information on the walkdown personnel and their qualifications.
Specifically, the staff reviewed the summary of the background, experience, and level of involvement for the following personnel involved in the seismic walkdown activities: equipment selection personnel, seismic walkdown engineers (SWEs), licensing basis reviewers, IPEEE reviewers, peer review team , and operations staff.
Based on the review of the licensee's submittals, the NRC staff concludes that those involved in the seismic walkdown activities have the appropriate seismic background, knowledge and experience, as specified in Section 2 of the walkdown guidance.
3.2.2 Development of the SWELs Section 3, Selection of SSCs, of the walkdown guidance provides information to licensees for selecting the SSCs that should be placed on the SWELs, so that they can be walked down by qualified personnel.
The NRC staff reviewed the overall process used by the licensee to develop the Braidwood, Unit 2, base list, SWEL 1 (sample list of designated safety functions equipment), and SWEL 2 (sample list of spent fuel pool (SFP)-related equipment). The licensee stated that the process for selecting a sample of SSCs for safe shutting down the reactor and maintaining containment integrity began with IPEEE Success Path Equipment List (SPEL) . The IPEEE SPEL was then subjected to the screening process provided by the walkdown guidance to identify items to be included in SWEL 1.
The licensee provided the SWEL 1 for Braidwood, Unit 2, in Appendix B, Table B-3, of the walkdown report and discussed this list in Section 4.2 of the walkdown report. The SWEL 2 items are listed in Table B-4.
The overall equipment selection process followed the screening process shown in Figures 1-1 and 1-2 of the walkdown guidance as discussed above. Based on Appendix B of the walkdown report, Braidwood, Unit 2, SWELs 1 and 2, meets the inclusion requirements of the walkdown guidance. Specifically, the following attributes were considered in the sample selection:
- A variety of systems, equipment and environments,
- IPEEE equipment,
- Major new or replacement equipment, and
- Risk considerations.
It is possible that some classes of equipment will not be represented on the SWEL due to individual plant configurations , and the walkdown guidance screening process followed to select the final SWEL equipment. The walkdown guidance recognizes this is due to the equipment not
being present in the plant (e.g ., some plants generate direct current power using inverters and, therefore , do not have motor generators) or the equipment being screened out during the screening process (the screening process is described in Section 3 of the walkdown guidance).
Based on the information provided , the NRC staff noted that a detailed explanation was provided justifying cases where specific classes of equipment were not included as part of the SWEL and concludes that these exclusions are acceptable.
The NRC staff noted that a rapid drain-down list was not included as part of the SWEL 2, as described in Section 3 of the guidance. In Section 4.2.2.4 of the walkdown report, the licensee stated there are no components that could, upon failure , result in rapid drain-down of the SFP water level to below 3 meters (1 0 feet) above the top of the fuel. After reviewing the information provided in this section, the staff concludes that the licensee provided adequate justification for not including rapid drain-down items as part of the SWEL 2.
After reviewing the SWEL, the NRC staff concludes that the sample of SSCs represents a diversity of component types and assures inclusion of components from critical systems and functions, thereby, meeting the intent of the walkdown guidance. In addition, the NRC staff notes that the equipment selection personnel were appropriately supported by plant operations staff as described in the walkdown guidance.
3.2.3 Implementation of the Walkdown Process Section 4, Seismic Walkdowns and Area Walk-Bys, of the walkdown guidance provides information to licensees regarding the conduct of the seismic walkdowns and area walk-bys for each site.
The NRC staff reviewed Section 5 of the walkdown report, which summarizes the results of the seismic walkdowns and area walk-bys, including an overview of the number of items walked down and the number of areas walked-by. The walkdown report states that teams, which consisted of two trained SWEs, conducted the seismic walkdowns and area walk-bys. According to the signed seismic walkdown checklists (SWCs) and area walk-by checklists (AWCs), these activities were conducted during the week of July 30, 2012. In addition , a subsequent set of walkdowns were performed by the end of 2012, and throughout 2013, as referred to in the January 6, 2014, letter, from the licensee. The purpose of the last activity was to complete a number of items that were inaccessible during the initial walkdowns and to complete internal inspections on electrical cabinets. Several of the walkdown results were provided as part of this update. The complete set of walkdown results were provided as part of the second update submitted to the NRC on March 31 , 2014.
The walkdown report also states that the SWEs discussed their observations and judgments with each other during the walkdowns . Additionally, the SWEs agreed on the results of their seismic walkdowns and area walk-bys before reporting the results of their review. Appendices C and 0 of the initial walkdown report, Appendices AC and AD of Annex A, and Appendices BC and BD of Annex B of the updated report, provide the completed SWCs and AWCs, documenting the results for each item of equipment on the SWELs and each area containing SWEL equipment. The licensee used the checklists provided in Appendix C of the walkdown guidance report without modification.
The licensee documented cases of potentially adverse seismic conditions (PASCs) in the checklists for further evaluation . The licensee stated that none of the issues identified during the walkdowns were ultimately judged to be PASCs. Tables 5-2 and 5-3 of the walkdown report list the conditions identified during the initial seismic walkdowns and the area walk-bys. Tables A5-2 , A5-3 , B5-2 and B5-3 of the updated report list the PASCs identified during the subsequent walkdowns . The tables describe how each condition was addressed (e.g., placement in the CAP) , its resolution and current status.
Based on the initial review of the checklists, the NRC staff was unable to confirm that all the PASCs identified during the walkdowns were included in this table. By letter dated November 1, 2013, the staff issued two questions in a request for additional information (RAI) in order to obtain additional clarification regarding the process followed by the licensee when evaluating conditions identified in the field during the walkdowns and walk-bys. Specifically, in RAI 1, the staff requested the licensee to provide further explanation regarding how a field observation was determined to be PASC, and to ensure that the basis for determination was addressed using normal plant processes and documented in the walkdown report. In response to RAI 1, the licensee confirmed that all conditions identified during the walkdowns and walk-bys were documented as issue reports (IRs) in the Braidwood, Unit 2, CAP. The licensee referred to Tables 5-2 and 5-3 of the initial walkdown report and Tables A5-2, A5-3, B5-2 and B5-3 of the updated walkdown reports , which include the IRs identified during the walkdowns and area walk-bys for Braidwood , Unit 2. In addition, the licensee stated that all identified nonseismic potentially adverse conditions , such as housekeeping and material conditions items, were identified by SWEs and addressed through the CAP. Furthermore, the licensee confirmed that, based on its review of Braidwood, Unit 2, walkdown process and the information submitted in the walkdown report, that no new conditions were identified that would require an additional supplement or additional CAP entries.
After evaluating the licensee's response and reviewing summary Tables 5-2, 5-3, A5-2 , A5-3, B5-2 and B5-3 of the walkdown reports, the NRC staff concludes that the licensee responded appropriately to RAI 1. In addition, the staff concludes that conditions, including any PASCs, were properly identified and documented, and the summary tables provided are considered complete.
In addition to the information provided above, the NRC staff notes that anchorage configurations were verified to be consistent with existing plant documentation for at least 50 percent of the SWEL items, in accordance with Section 4 of the walkdown guidance.
Tables E-1 and E-2 of the initial walkdown report, list equipment and areas that were inaccessible during the 180-day period. Table E-1 lists 18 SWEL components that were inaccessible at the time of the walkdowns due to a required outage, its respective completion date, and status.
Table E-2 lists those cabinets that were not internally inspected during the initial walkdowns.
Items identified in Tables E-1 and E-2 were walked down by the end of 2012, and during 2013, before the Spring 2014, comm itment. As confirmed by the January 6, 2014, letter, from the licensee, walkdown results were provided for most of these items. The walkdown results for several internal cabinet inspections were submitted to the NRC. As part of the March 31 , 2014, submittal.
Based on the information provided in the licensee's submittals, the NRC staff concludes that the licensee's implementation of the walkdown process meets the intent of the walkdown guidance.
3.2.4 Licensing Basis Evaluations and Results Section 5, Seismic Licensing Basis Evaluations, of the walkdown guidance provides information to licensees regarding the conduct of licensing basis evaluations for items identified during the seismic walkdowns as degraded , nonconforming, or unanalyzed that might have potential seismic significance.
The NRC staff reviewed Section 6 of the Braidwood , Unit 2, walkdown report which discusses the process for conducting the seismic licensing basis evaluations of the PASCs identified during the seismic walkdowns and area walk-bys. The licensee stated that it performed licensing basis evaluations and resolved PASCs using the plant's CAP. Tables 5-2 and 5-3 of the intial walkdown report, and Tables A5-2, A5-3, B5-2 and B5-3 of the updated walkdown report, list the key licensee findings, and provide a complete list of the potentially degraded , nonconforming , or unanalyzed conditions . These tables also describe the actions taken or planned to address these conditions, including the current status of each of the items the licensee entered into the CAP.
The NRC staff reviewed the CAP entries and the description of the actions taken or planned to address potential deficiencies. The staff concludes that the licensee appropriately identified degraded , nonconforming, or unanalyzed conditions and entered them into the CAP, which meets the intent of the walkdown guidance.
3.2.5 Conclusion Based on the discussion above, the NRC staff concludes that the licensee's implementation of seismic walkdown methodology meets the intent of the walkdown guidance for personnel qualifications, development of SWELs, implementation of the walkdown process, and seismic licensing basis evaluations.
3.3 Peer Review Section 6, Peer Review, of the walkdown guidance provides licensees with information regarding the conduct of peer reviews for the activities performed during the seismic walkdowns . Page 6-1 of the walkdown guidance identifies the following activities to be conducted during the peer review process:
- Review a sample of the checklists prepared for the seismic walkdowns and area walk-bys.
- Review the licensing basis evaluations.
- Review the decisions fo r entering the potentially adverse conditions into the CAP.
- Review the walkdown report.
- Summarize the results of the peer review process in the walkdown report.
The NRC staff reviewed the information provided in Section 8 of the Braidwood , Unit 2, walkdown report which describes the conduct of the peer review. In addition, the staff reviewed the response to RAI 2. In RAI 2, the staff requested the licensee to provide additional information on the overall peer review process that was followed as part of the walkdown activities. Specifically, the staff requested the licensee to confirm that the activities identified on page 6-1 of the walkdown guidance were assessed and documented in the report. The licensee was also requested to confirm that any individual involved in performing any given walkdown activity was not a peer reviewer for that same activity. In response to RAI 2, the licensee confirmed that all the activities identified on page 6-1 of the walkdown guidance were included as part of the peer-review process, and referred to the summary of the peer review activities provided in Section 8, and the full-peer review report in Appendix F of the walkdown report. In addition, the licensee stated that there were no cases where any peer reviewer reviewed their own work.
The NRC staff reviewed the licensee's summary of each of these activities, which included a discussion of the peer review team members' qualifications and level of involvement, the peer review findings, and resolution of peer review comments. After reviewing the licensee's submittals, the NRC staff concludes that the licensee sufficiently documented the results of the peer review activities and how these reviews affected the work described in the walkdown report.
Based on the discussion above, the NRC staff concludes that the licensee's results of the peer review and subsequent actions taken in response to the peer review meets the intent of Section 6 of the walkdown guidance.
3.4 IPEEE Information Section 7, IPEEE Vulnerabilities , of the walkdown guidance provides information to licensees regarding the reporting of the evaluations conducted and actions taken in response to seismic vulnerabilities identified during the IPEEE program . Through the IPEEE program and Generic Letter 88-20, "Individual Plant Examination of External Events for Severe Accident Vulnerabilities ," licensees previously had performed a systematic examination to identify any plant-specific vulnerabilities to severe accidents.
The licensee provided background information regarding their IPEEE program and referenced several submittals to the NRC . The licensee stated that no vulnerabilities were reported in the previous IPEEE reports. However, a few plant improvements were identified in Appendix G.
Table G-1 lists the improvements, the IPEEE-proposed resolution, the actual resolution and the resolution date. All IPEEE plant improvements and associated actions are complete.
Based on the NRC staff's review of Section 7 of the walkdown report, the staff concludes that the licensee's summary of the IPEEE is consistent with and meets the intent of Section 7 of the walkdown guidance.
3.5 Planned Upgrades The licensee did not identify any planned or newly installed protection and mitigation features in the walkdown report.
3.6 NRC Oversight 3.6.1 Independent Verification by Resident Inspectors On July 6, 2012,10 the NRC issued Temporary Instruction (TI) 2515/188 "Inspection of Near-Term Task Force Recommendation 2.3 Seismic Walkdowns. " In accordance with the Tl, NRC inspectors independently verified that Braidwood, Unit 2, licensee implemented the seism ic walkdowns in accordance with the walkdown guidance. Additionally, the inspectors independently performed walkdowns of a sample of seismic protection features. The inspection report dated February 7, 2013,11 documents the results of this inspection and stated that no findings were identified.
4.0 CONCLUSION
The NRC staff concludes that the licensee's implementation of seismic walkdown methodology meets the intent of the walkdown guidance. The staff concludes that the licensee, through the implementation of the walkdown guidance activities, and in accordance with plant processes and procedures, verified the plant configuration with the current seismic licensing basis; addressed degraded , nonconforming , or unanalyzed seism ic conditions ; and verified the adequacy of monitoring and maintenance programs for protective features . Furthermore, the staff notes that no immediate safety concerns were identified. The NRC staff reviewed the information provided and determined that sufficient information was provided to be responsive to Enclosure 3 of the 50.54(f) letter.
10 ADAMS Accession No. ML 121.56A052 11 ADAMS Accession No. ML13038A635
If you have any questions, please contact me at 301-415-6606 or by e-mail at Joei .Wiebe@nrc.gov.
Sincerely, IRA!
Joel S. Wiebe, Senior Project Manager Plant Licensing 111-2 and Planning and Analysis Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-457
Enclosure:
Staff Assessment of Seismic Walkdown Report cc w/encl : Distribution via Listserv DISTRIBUTION :
PUBLIC RidsOgcMaiiCenter Resource RidsRgn3MaiiCenter Resource LPL3-2 R/F RidsOpaMail Resource BRini , EDO Rl, Rll , Rill, RIV RidsNroDsea RidsNrrLASRohrer Resource RidsAcrsAcnw MaiiCTR Resource RidsNrrDorl Resource RidsNrrPMBraidwood Resource RidsNrrDorllpl3-2 Resource LRegner, NRR NChokshi, NRO SFianders, NRO DJackson, NRO RKaras , NRO FVega , NRO MJardaneh, NRO NDiFrancesco, NRR ADAMS A ccess1on N um ber: ML14101A445
- concurrence b)y e-ma1 OFFICE DORL/LP3-2/PM JLD/PMB/PM DORLILPL3-2/LA DSEA/RGS2 NAME JWiebe NDifrancesco SRohrer DJackson*
- DATE 6/2/14 6/4/14 6/3/14 4/ 3 /2014 OFFICE DORLILPL3-2/BC DORLILPL3-2/PM NAME TTate JWiebe DATE 6/4/14 6/4/14 OFFICIAL RECORD COPY