ML14073A548
| ML14073A548 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 05/01/2014 |
| From: | Wang A Plant Licensing Branch IV |
| To: | Entergy Operations |
| Wang A | |
| References | |
| TAC MF0167 | |
| Download: ML14073A548 (12) | |
Text
Vice President, Operations Entergy Operations, Inc.
River Bend Station 5485 U.S. Highway 61 N St. Francisville, LA 70775 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 May 1, 2014
SUBJECT:
RIVER BEND STATION, UNIT 1 -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. MF0167)
Dear Sir or Madam:
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, Subpart 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 Tohoku Earthquake and subsequentJsunami. 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 letter dated June 18, 2013, Entergy Operations, Inc. (Entergy), submitted its Seismic Walkdown Report as requested in Enclosure 3 of the 50.54(f) letter for River Bend Station, Unit 1.
By letter dated November 21, 2013, Entergy 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.
If you have any questions, please contact me at 301-415-1445 or by e-mail at Alan.Wang@nrc.gov.
Docket No. 50-458
Enclosure:
Staff Assessment of Seismic Walkdown Report cc w/encl:
Distribution via Listserv Sincerely, Alan B. Wang, Project Manager Plant Licensing IV-2 and Decommissioning Transition Branch Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
STAFF ASSESSMENT OF SEISMIC WALKDOWN REPORT NEAR-TERM TASK FORCE RECOMMENDATION 2.3 RELATED TO THE FUKUSHIMA DAI-ICHI NUCLEAR POWER PLANT ACCIDENT
1.0 INTRODUCTION
ENTERGY OPERATIONS. INC.
RIVER BEND STATION. UNIT 1 DOCKET NO. 050-458 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, Subpart 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. of 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 IPEEE [Individual Plant Examination of External Events] program and a description of the actions taken to eliminate or reduce them...
- d.
Results of the walkdown including key findings and identified degraded, nonconforming, or unanalyzed conditions...
. e.
Any planned or newly installed protection 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 (NEI) staff submitted Electric Power Research Institute (EPRI) 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 Entergy Operations, Inc. (the licensee) provided a response to Enclosure 3 of the 50.54(f) letter Required Response Item 2, for River Bend Station, Unit 1 (RBS).
In addition to the aforementioned letter, the licensee, by letter dated June 18, 2013, 6 provided an updated submittal to the initial seismic walkdown report for RBS.
For the RBS review, the purpose of the latter submittal was to update and provide information on inaccessible SSCs, which were not completed in the first submittal.
The NRC staff reviewed the walkdown reports and determined that additional information would assist the staff in completing its review.
By letter dated November 1, 2013,7 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's request for additional information (RAI) by letter dated November 21, 2013.8 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 initiallicensing, 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 mu.st perform, and the specific values or ranges of values chosen for controlling parameters as reference bounds for the design.
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 3 ADAMS Package Accession No. ML121640872.
4 ADAMS Accession No. ML12145A529.
5 ADAMS Package Accession.No. ML123420135.
6 ADAMS No. ML13198A075.
7 ADAMS No. ML133048418.
8 ADAMS Accession No. ML13330A999.
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 (CLB) 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 RBS 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 NRC staff reviewed Section 2 of the walkdown report, focusing on the summary of the SSE, methodology and the design codes used in the design of RBS.
Based on its review, the NRC 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, 20129, the licensee confirmed that it would utilize the walkdown guidance in the performance of the seismic walkdowns at RBS.
The walkdown report dated November 27, 2012, and supplemented on June 18, 2013, 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 S_eismic Walkdown Equipment Lists (SWELs)
Implementation of the Walkdown Process Licensing Basis Evaluations and Results 9 ADAMS Accession No. ML12198A001.
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 4 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 RBS Base lists, and the 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 safe shutdown equipment list (SSEL, also known as the RBS IPEEE equipment list), developed to address the success path capable of achieving and maintaining a safe shutdown condition for at least 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following a SSE event, was the starting point for the Base List 1. The SSEL list, which addresses SSCs associated with the reactor safe shutdown functions and previously reviewed by the NRC as part of the IPEEE issue, is a valid starting point to develop the plant's base list.
The licensee provided Base List 1 and SWEL 1 for RBS in Tables B.1 and B.2, respectively, in Attachment B of the walkdown report.
.This equipment selection process followed the screening process shown in Figures 1-1 and 1-2 of the walkdown guidance. Based on the walkdown report, RBS SWELs 1 and 2 meet 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 Risk considerations Due to individual plant configurations and the walkdown guidance screening process followed to select the final SWEL equipment, it is possible that some classes of equipment will not be represented on the SWELs. 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 (e.g., Class 11 or 13) as part of the SWEL, and concludes that these exclusions are acceptable.
The licensee provided Base List 2 in Table B.3 in Attachment B of the walkdown report. The NRC staff also noted that items that could cause rapid drain-down to a level below 10 feet above the top of the fuel were not included as part of the SWEL 2, as described in Section 3 of the guidance. In Section 3.2 of the walkdown report, the licensee stated that there are no components that could, upon failure, result in rapid drain-down of the SFP water level to below 10 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 SWELs 1 and 2, 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 7,0 of the updated 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 at least two-person teams of trained Seismic Walkdown Engineers (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 first conducted during the 2 weeks during October 2012 and subsequent walkdowns were.conducted during the February to March 2013 time period (prior to and during RF0-17) for the 11 items that were inaccessible during the*
initial inspection. The walkdown report also states that the SWEs discussed their obser-Vations 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.
- Attachments C and J of the walkdown reports provide the completed SWCs and AWCs, documenting the results for each item of equipment on the SWELs 1 and 2 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. Attachment E of the walkdown report shows that 20 PASCs were identified during the seismic walkdowns and the area walk-bys. The licensee stated that each PASC was entered into the plant's CAP for resolution. Based on the initial review of the checklists, the staff was unable to confirm that all the PASCs identified during the walkdowns were included in this table. As such, by letter dated November 1, 2013, the NRC staff issued two questions in an 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 a 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 there are no new PASCs to report because all PASC items were addressed and included in previous submittals. The licensee referenced the description of the walkdown process as described in Attachment E of the RBS walkdown report, and stated that all PASCs were entered into the plant's CAP.
After evaluating the licensee's response and reviewing the updated Attachment E of the submittal, the NRC staff concludes that the licensee responded appropriately to RAI 1 and PASCs were properly identified and documented and the summary table included in Attachment E is considered complete.
In addition to the information provided above, the NRC staff noted that the method for verifying anchorage configurations was summarized in Section 7.1 of the walkdown report and 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..
The NRC staff notes that the walkdown report does not explicitly specify that cabinets were opened to ensure that visibly accessible internal component mountings are adequate. Based on a review of the licensee's general walkdown methodology as described in Section 7.1 of the walkdown report and the SWCs and AWCs in Attachments C and D of the walk down report, the staff confirmed that cabinets were opened, where applicable, by the seismic walkdown team.
The equipment that was inaccessible during the 180-day period is listed in Attachments J and K of the RBS walkdown report. There were 11 RBS SSCs in SWCs and seven AWCs that could only be accessed during a plant outage. The licensee stated that these items were walked down at RF0-17 and the updated report, submitted on June 18, 2013, confirms that additional walkdowns were conducted February 4-24, 2013, to perform internal inspections of selected electrical equipment cabinets that were not completely inspected or were not opened during the initial walkdowns. No PASCs were identified that would require additional CAP entries. The NRC staff reviewed the seismic walkdown checklists,provided in Attachme~ts J and K of the updated RBS walkdown report and confirmed that cabinets were opened to determine if any adverse conditions existed of internal equipment.
Based on the information provided in the licensee's submittals, the NRC staff concludes that the licensee's implementation of the walkdown proc~ss meets the intent of the walkdown guidance.
. 3.2.4 Licensing Basis Evaluati'ons 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 8.0 of the RBS 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 its licensing basis evaluations for all the identified PASCs.
For those licensing basis evaluation items not readily concluded through the process to meet their CLB were entered into the CAP. Attachment E of the walkdown report lists the key licensee findings, and provides a complete list of the potentially degraded, nonconforming, or unanalyzed conditions. Attachment E of the walkdown report also describes 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 licensing basis evaluations and 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 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 the selection of the SSCs included on the SWELs Review a sample of the checklists prepared for the seismic walkdowns and area walk-bys Review the licensing basis evaluations Review the decisions for 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 9 and Attachment G of the RBS 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 Section 9.0 and Attachment G of the RBS walkdown report.
In addition, the licensee stated that none of the peer review engineers were involved in the seismic walkdown inspection process in order to further demonstrate.the independence of the peer review process.
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 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 Gel')eric Letter 88-20, "Individual Plant Examination of External Events for Severe Accident Vulnerabilities," dated November 23, 1988,10 licensees previously had performed a systematic examination to identify any plant-specific vulnerabilities to severe accidents.
The licensee reviewed the 1993 I PEEE final report and supporting documentation to identify items of seismic vulnerabilities by the IPEEE program. Also additional plant documentation was reviewed to identify the eventual resolutions.
No seismic vulnerabilities were identified by the RBS IPEEE program as documented in Attachment A.
Based on the NRC staff's review of Section 5.0 of the walkdown report, the NRC staff concludes that the licensee's identification of plant-specific vulnerabilities (including anomalies, outliers and other findings) identified by the IPEEE program, as well as actions taken to eliminate or reduce them, meets the intent of Section 7 of the walkdown guidance.
10 ADAMS Accession No. ML031150465.
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, 11 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 the RBS licensee implemented the seismic walkdowns in accordance with the walkdown guidance. Additionally, the inspectors independently performed walkdowns of a sample of seismic protection features. The inspection report dated May 8, 2013, 12 documents the results of this inspection and states 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, through the implementation of the walkdown guidance activities and, in accordance with plant processes and procedures, the licensee verified the plant configuration with the current seismic licensing basis; addressed degraded, nonconforming, or unanalyzed seismic 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 concludes that the licensee responded appropriately to Enclosure 3 of the 50.54(f) letter.
11 ADAMS Accession No. ML12156A052.
12 ADAMS Accession No. ML13128A427.
ML14073A548 OFFICE NRR/DORLILPL4-2/PM NAME A Wang DATE 04/14/14 OFFICE NRO/DSEA/RGS2(BC NAME DJackson*
DATE 03/12/14 Sincerely,
/RA/
Alan B. Wang, Project Manager Plant Licensing IV-2 and Decommissioning Transition Branch
- Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation RidsRgn4MaiiCenter Resource JNick, EDO RIV LRegner, NRR NChokshi, NRO SFianders, NRO DJackson, NRO RKaras, NRO FVega, NRO MJardaneh, NRO NDiFrancesco, NRR
- concurrence by e-mail NRR/DORLILPL4-2/LA JLD/PMB/PM JBurkhardt NDiFrancesco 04/10/14 04/15/14 NRR/DORLILPL4-2/BC NRR/DORLILPL4-2/PM DBroaddus A Wang 05/01/14 05/01/14