ML13337A395
| ML13337A395 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 12/02/2013 |
| From: | Mulligan K J Entergy Operations |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| GNRO-2013/00087 | |
| Download: ML13337A395 (9) | |
Text
Entergy GNRO-2013/00087 December 2, 2013 u.s. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Entergy Operations, Inc. P. o. Box 756 Port Gibson, MS 39150 Kevin J. Mulligan Site Vice President Grand Gulf Nuclear Station Tel. (601) 437-7500
SUBJECT:
Supplemental Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Hazard Walkdowns Conducted to Verify Current Plant Compliance with the Current Licensing Basis (CLB) for Seismic Requirements Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29
REFERENCES:
- 1. NRC Letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1,2.3, and 9.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12,2012 (ML12053A340, GNRI-2012100059)
- 2. Electrical Power Research Institute (EPRI), EPRI Seismic Walkdown Guidance, For Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, EPRI Report 1025286, dated 2012 (ML 12188A031)
- 3. Entergy Letter to NRC, Seismic Walkdown Report -Entergy's Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated November 26, 2012 (ML 12352A070, GNRO-2012/00141)
- 4. Internal NRC memorandum from Lisa M. Regner to Matthew A. Mitchell,
Subject:
Summary of the September 12,2013, Public Meeting to Discuss Implementation of Japan Lessons-Learned Near-Term Task Force Recommendation 2.3, Seismic Walkdowns, dated October 4,2013 (ML 13266A424)
- 5. NRC Letter, Request for Additional Information Associated with Near-Term Task Force Recommendation 2.3, Seismic Walkdowns, dated November 1, 2013 (ML 133048418, GNRI-2013/00169)
GNRO-2013/00087 Page 2 of 3
Dear Sir or Madam:
On March 12,2012, the U.S. Nuclear Regulatory Commission (NRC) staff issued a letter requesting additional information per Title 10 Code of Federal Regulations 50.54(f) (Reference 1). The letter requested licensees to conduct seismic hazard walkdowns to verify current plant configuration with the Current Licensing Basis (CLB). The NRC endorsed an Electric Power Research Institute (EPRI) guidance document that resulted from this effort (Reference
- 2) because the NRC staff determined that the use of the guidance, coupled with appropriate training, would meet the objectives and requests for information requested in the 50.54(f) letter. Entergy Operations, Inc.'s (Entergy's)
Grand Gulf Nuclear Station (GGNS) submitted the walkdown report on November 26,2012 (Reference 3). Following the staff's initial review of the walkdown reports, regulatory site audits were conducted at a sampling of plants. By internal NRC correspondence (Reference
- 4) the NRC summarized a public Webinar conducted on September 12, 2013, and provided written questions identifying the areas where additional information could assist the NRC staff in completing their reviews of the walkdown reports. These questions were consolidated and on November 1, 2013, Reference 5 was issued by the NRC as a request for additional Information (RAI). Entergy is replying to the RAI in Reference 5 for GGNS. The enclosed attachment provides additional information not required by the original request for information (Reference
- 1) to assist the NRC staff in completing their review of the Seismic Hazard Walkdowns conducted at GGNS. This letter contains no new regulatory commitments.
If you have any questions regarding this submittal, please contact Mr. Jeff Seiter at (601) 437-2344.
I declare under penalty of perjury that the foregoing is true and correct. Executed on December 2, 2013. Sincerely, KJM/slw
Attachment:
Grand Gulf Nuclear Station's Attachment to Support the NRC Review of Seismic Walkdown Inspections Cc: (See next page)
GNRO-2013/00087 Page 3 of 3 cc: U. S. Nuclear Regulatory Commission ATTN: Mr.. Marc Oapas Regional Administrator, Region IV 1600 East Lamar Boulevard Arlington, TX 76011-4511 U. S. Nuclear Regulatory Commission Attn: Director, Office of Nuclear Reactor Regulation Washington, DC 20555-0001 U. S. Nuclear Regulatory Commission A TIN: Mr. Alan Wang, NRR/DORL Mail Stop OWFN/8 81 Washington, DC 20555-0001 NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150 Attachment to GNRO-2013/00087 Grand Gulf Nuclear Station's Attachment to Support the NRC Review of Seismic Walkdown Inspections Attachment to GNRO-2013/00087 Page 1 of 5 Grand Gulf Nuclear Station's Attachment to Support the NRC Review of Seismic Walkdown Inspections The format for the Request for Additional Information (RAI) responses below is as follows. The RAI is listed in its entirety as received from the U.S. Nuclear Regulatory Commission (NRC). This is followed by Entergy Operations, Inc.'s (Entergy's)
Grand Gulf Nuclear Station (GGNS) RAI response to the individual question.
NRC Question 1: Conduct of the walkdowns, determination of potentially adverse seismic conditions (PASCs), dispositioning of issues, and reporting As a result of the audits and walkdown report reviews, the NRC staff noted that licensees' interpretations of the seismic walkdown guidance varied, which resulted in meaningful differences in the process used to disposition identified issues and in the documentation that was provided to the NRC staff. In particular, the application of engineering judgment in determining what constituted a potentially adverse seismic condition (PASC), the threshold for conducting licensing basis evaluations (LBEs), and determining what information was to be reported to the NRC staff varied. The NRC staff intended that conditions initially marked No (N) or Unknown (U) in the field by the seismic walkdown engineers (SWEs) for which an analysis or calculation was performed would be considered as PASCs and that an analysis or calculation constituted an LBE. The walkdown guidance allows for analysis as part of engineering judgment; however, the intent was to allow for only simple analyses that could be readily performed in support of engineering judgment.
Further, the walkdown activities were intended to allow for transparency in the licensee's process to demonstrate that PASCs were appropriately identified, that they were addressed in an appropriate manner, and the basis documented such that the current condition of the plant was clearly consistent with the CLB with regard to seismic capability.
During the audits, the NRC staff identified examples of field observations that were deemed not to be PASCs. However, the basis for the determination was not clearly recorded.
In some cases, the field checklists were amplified by noting that the basis was engineering judgment.
During site audit discussions, the staff was able to trace the basis for the engineering judgments and found that in many cases they were appropriate.
It is expected that these situations would not be included in the walkdown report. There were other situations that a PASC and LBE were not reported; however, the NRC staff found during the audit that a calculation, analysis (more than just simple), or evaluation was conducted but informally.
An example is a confirmatory calculation performed to demonstrate that six anchor bolts out of eight was not a seismically adverse condition.
Another example would be an analysis to demonstrate that an existing, slightly short weld was as seismically sound as the prescribed weld length in the plant design documentation.
The staff expected these types of conditions and evaluations to be captured in the licensee's normal plant processes (e.g., condition report or corrective action program (CAP)), and also reported in the walkdown report, since they were potentially adverse seismic conditions that required more than applying judgment or simple analysis to address. The NRC staff also found that the process that was used to deal with a field observation that was deemed to be a PASC was also not completely described or captured in the report. In many cases, the licensee reported that an LBE was not performed.
Attachment to GNRO-2013/00087 Page 2 of 5 However, during the audits, it was clear that an LBE (or an equivalent determination method) was performed and used in determining whether a PASC should be entered into the CAP. The staff expects that these conditions would be reported in the walkdown report. On the whole, through the audits, the NRC staff found that it was able to conclude that the intent of the guidance was met when the licensee's overall process was completely explained, the information was updated to reflect the actual process, and results were updated. The assessments conducted by the licensees of the audited plants also identified the lapse in the description of the process used by the licensee to identify a PASC and disposition it. Therefore, in order to clarify the process that was followed, please provide a description of the overall process used by the licensee (and its contractors) to evaluate observations identified in the field by the SWEs. The process should include how a field observation was determined to be a PASC or not and how the bases for determinations were recorded.
Once a determination was made that an observation was a PASC, describe the process for creating a condition report (or other tracking mechanism), performing the LBE (or other determination method), and the resultant action, such as entering it into the CAP, or documenting the result and basis. Also, in order to confirm that the reported information supports concluding that the plant meets the CLB, please follow one of the following three acceptable alternatives: (a) Provide a supplement to the table or text from the original walkdown report, if needed, to include similar conditions as the above examples and situations and for conditions for which a calculation, analysis (if more than a simple analysis), or evaluation was used for a determination.
The supplement should include a short description of each condition, how it was dispositioned and the basis for the disposition, as follows: 1) for each condition that was entered into the CAP, provide the CAP reference number, initiation date, and (if known) the planned completion date, or 2) for all other conditions, provide the result of the LBE (or other determination method), the basis for the result, and how (or where) the result was captured in the plant's documentation or existing plant process. (b) Following the plant's standard procedures, confirm that a new CAP entry has been made to verify if appropriate actions were taken when reporting and dispositioning identified PASCs (including conditions for which a calculation, analysis (if more than a simple analysis), or evaluation was used for a determination).
The eventual CAP closeout, including the process followed and actions taken, should be in sufficient detail to enable NRC resident inspectors to follow up. (c) If no new conditions are identified for addition to the supplement or the CAP entry mentioned above is deemed not necessary, provide a statement of confirmation that all potentially seismic adverse conditions (including conditions for which a calculation, analysis (if more than a simple analysis), or evaluation was used for a determination) identified during the walkdowns and walk-bys were addressed and included in the report to the NRC. Response to Question 1: In November of 2012, GGNS documented in Reference 1 the results of the seismic walkdown effort undertaken for resolution of Near Term Task Force (NTTF) Recommendation 2.3: Seismic, in accordance with the Electric Power Research Institute (EPRI) Guidance (Reference 2), and provided the information necessary for responding to Enclosure 3 to the 50.54(f) Letter (Reference 3).
Attachment to GNRO-2013/00087 Page 3 of 5 This industry guidance document, EPRI Report 1025286 was formally endorsed by the NRC on May 31,2012. GGNS has committed to using this NRC-endorsed guidance as the basis for conducting and documenting seismic walkdowns for resolution of NTTF. Recommendation 2.3: Seismic. As a result of that commitment Entergy prepared a Fleet procedure, EN-DC-i68, in strict accordance with the EPRI guidance for completing the walkdowns with uniform fleet results. To supplement the site workforce in order to complete the walkdowns, Entergy Corporation hired ENERCON Services to perform the walkdowns with site assistance and assisted in the peer review process. Seismic walkdowns were performed in accordance with Section 4 of the EPRI Guidance for all items on the Seismic Walkdown Equipment List (SWEL) (SWEL 1 plus SWEL 2), except for those determined to be inaccessible and deferred (see Section 6.3 of the Site Report). To document the results of the walkdown, Seismic Walkdown Checklist (SWC) with the same content as that included in Appendix C of the EPRI Guidance was created for each item. Additionally, where permitted by Plant Operations, photographs were taken of each item and included on the corresponding final revision of the SWC. During the course of the seismic walkdowns and area walk-bys, the objective of the SWE teams was to identify existing degraded, non-conforming, or unanalyzed plant conditions with respect to its current seismic licensing basis. When an unusual condition was observed by a SWE team in the field, the condition was noted on the SWC or Area Walk-by Checklist (AWC) form and briefly discussed between the two SWEs to agree upon whether it was a potentially adverse seismic condition.
These initial conclusions were based on conservative engineering judgment utilizing the training required for SWE qualification.
The walkdown sheets were annotated where appropriate with supporting reference or justification for the basis of its acceptance.
The walkdown sheets included explanation on why som;;) field conditions were not identified as PASC if they were previously addressed or documented by another process, Le., Seismic Qualification Utilities Group (SQUG), Modification, or previous coodmon report (CR). For conditions that were reasonably judged as insignificant to seismic response, the disposition was included on the SWC or AWe checklist and the appropriate question was marked "Y", indicating that no associated potentially adverse seismic condition was observed.
Unusual or uncertain conditions were reported to site personnel for further resolution through the CAP (see Section 8.2 of Reference 1). These conditions were generally related to housekeeping.
For conditions that were judged as potentially significant to seismic response, the condition was photographed, and the appropriate question on the SWC or AWe was marked "N" indicating that a potentially adverse seismic condition was observed.
The condition was then immediately reported to site personnel for further resolution and was documented for reporting in Attachment E of Reference
- 1. These conditions were generally related to housekeeping, non-conforming anchorage, or spatial interaction.
Conditions observed during the seismic walkdowns and area walk-bys that were determined to be potentially adverse seismic conditions are summarized in Attachment E of Reference 1, including how each condition has been addressed and its current status. Each potentially adverse seismic condition at GGNS was addressed by entry into the CAP.
Attachment to GNRO-2013/00087 Page 4 of 5 Unusual conditions that were not seismically significant were also entered into the CAP directly.
Further resolution of these conditions is not tracked or reported as part of the NTTF 2.3 Seismic Walkdown program, except by noting the CR numbers generated on the applicable SWCs and AWCs. After review of the Entergy report (Reference
- 1) we confirm that the reported information supports the conclusion that the plant meets its CLB in accordance with alternative (c) listed in the RAI question 1. No new conditions are identified for all of the potentially seismic adverse conditions identified during the walkdowns and walk-bys.
All items were addressed and included in the report to the NRC. NRC Question 2: Conduct of the Peer Review Process As a result of the walkdown report reviews, the NRC staff noted that some descriptions of the peer reviewers and the peer review process that was followed were varied and, in some cases, unclear. In some cases, the staff could not confirm details of the process, such as if the entire process was reviewed by the peer review team, who were the peer reviewers, what was the role of each peer reviewer, and how the reviews affected the work, if at all, described in the walkdown guidance.
Therefore, in order to clarify the peer review process that was actually used, please confirm whether the following information on the peer review process was provided in the original submittal, and if not, provide the following. (a) Confirmation that the activities described in the walkdown guidance on page 6-1 were assessed as part of the peer review process. (b) A complete summary of the peer review process and activities.
Details should include confirmation that any individual involved in performing any given walkdown activity was not a peer reviewer for that same activity.
If there were cases in which peer reviewers reviewed their own work, please justify how this is in accordance with the objectives of the peer review efforts. Also, if there are differences from the original submittal, please provide a description of the above information.
If there are differences in the review areas or the manner in which the peer reviews were conducted, describe the actual process that was used. Response to Question 2: The peer review for the NTTF Recommendation
2.3 Seismic
Walkdowns was performed in accordance with Section 6 of the EPRI Guidance (Reference 2). The peer review team was led by site personnel and supported by ENERCON Services personnel and was not part of the walkdown teams. The peer review included an evaluation of the following activities:
- review of the selection of the structures, systems, and components (SSCs) that are included in the SWEL;
- review of a sample of the checklists prepared for the Seismic Walkdowns and area walk-bys;
- sample in-field observations
- review of licensing basis evaluations and decisions for entering the potentially adverse conditions into the plant's CAP; and
- review of the final submittal report.
Attachment to GNRO*2013/00087 Page 5 of 5 At ieast two members ofthe peer review team (see Table 4.2 of Reference
- 1) were involved in the peer review of each activity.
the team member with the most relevant knowledge and experience taking the lead for that particular activity_
A designated overall Peer Review Team Leader provided oversight related to the process and technical aspects of the peer review, paying special attention to the interface between peer review activities involving different members of the peer review team. A more detailed description of the peer review is described in section 9.0 and attachment G of the submitted report reference
- 1. References
- 1. Entergy Letter to NRC, Seismic Walkdown Report -Entergy's Response to NRC Request for Information Pursuant to 10 CFR 50.54(f) Regarding the Seismic Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated November 26,2012 (ML 12352A070, GNRO-2012/00141)
- 2. Electrical Power Research Institute (EPRI), EPRI Seismic Walkdown Guidance, For Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, EPRI Report 1025286, dated 2012 (ML 12188A031)
- 3. NRC Letter, Request for Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Recommendations 2.1,2.3, and 9.3 ofthe Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident, dated March 12,2012 (ML 12053A340, GNRI-2012/00059)