L-PI-13-104, Response to Requests for Additional Information Associated with Near-Term Task Force Recommendation 2.3. Seismic Walkdowns
| ML13333B457 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 11/27/2013 |
| From: | Davison K Northern States Power Co, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-PI-13-104 | |
| Download: ML13333B457 (9) | |
Text
(l Xcel Energy Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch, MN 55089 L.:PI-13-104 November 27, 2013 10 CFR 50.54(f)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant Units 1 and 2 Docket Nos. 50-282 and 50-306 Renewed Facility Operating License Nos. DPR-42 and DPR-60 Prairie Island Nuclear Generating Plant. Units 1 and 2. Response to Requests for Additional Information Associated with Near-Term Task Force Recommendation 2.3.
Seismic Walkdowns
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, ADAMS Accession No. ML12056A046.
- 2. NSPM Letter to NRC, "PINGP Unit 1 - Final 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, ADAMS Accession No. ML12334A495.
- 3. NSPM Letter to NRC, "PINGP Unit 2 - Final 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, ADAMS Accession No. ML12334A470.
- 4. NRC Letter, "Request for Additional Information Associated with Near-Term Task Force Recommendation 2.3, Seismic Walkdowns,"
dated November 1, 2013, ADAMS Accession No. ML133048418.
On March 12, 2012, the Nuclear Regulatory Commission (NRC) Staff issued a request for information regarding Near-Term Task Force {NTTF) insights from the Fukushima Dai-ichi accident, to all NRC power reactor licensees and holders of construction permits in active or deferred status (Reference 1). Enclosure 3 of the March 12, 2012 letter contains specific Requested Actions, Requested Information, and Required
Document Control Desk Page 2 Responses associated with Near-Term Task Force (NTTF) Recommendation 2.3, Seismic.
Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, on behalf of the Prairie Island Nuclear Generating Plant (PINGP), submitted the required responses to the Requested Information for NTTF Recommendation 2.3, Seismic, for Units 1 and 2 in two letters dated November 26, 2012 (References 2 and 3).
On November 1, 2013, the NRC Staff provided Requests for Additional Information (RAis) in Reference 4, regarding the Recommendation 2.3, Seismic Walkdowns. The enclosure to this letter provides NSPM's responses to these NRC RAis.
If there are any questions, or if additional information is needed, please contact Ms. Jennie Wike, Licensing Engineer, at 612-330-5788.
Summary of Commitments:
This letter makes no new commitments and no revisions to existing commitments.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on November 27, 2013.
Kevin Davison Site Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure cc: Administrator, Region Ill, USNRC Director, Office of Nuclear Reactor Regulation (NRR)
NRR Project Manager, Prairie Island Nuclear Generating Plant, US NRC Senior Resident Inspector, Prairie Island Nuclear Generating Plant, USNRC
Enclosure Prairie Island Nuclear Generating Plant, Units 1 and 2, Response to Requests for Additional Information Associated with NTTF Recommendation 2.3, Seismic Walkdowns
1.0 INTRODUCTION
On March 12, 2012, the Nuclear Regulatory Commission (NRC) Staff issued a request for information regarding Near-Term Task Force (NTTF) insights from the Fukushima Dai-ichi accident, to all NRC power reactor licensees and holders of construction permits in active or deferred status (Reference 1). Enclosure 3 of Reference 1 requested that licensees conduct seismic hazard walkdowns to verify the plant configuration with the current licensing basis, in order to address the Near-Term Task Force (NTTF) Recommendation 2.3, Seismic.
The Nuclear Energy Institute (NEI), with Electrical Power Research Institute (EPRI), prepared industry guidance to assist licensees in responding to this NRC request. The industry guidance document, EPRI Technical Report 1025286, Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic, dated June 2012 (Reference 5), was endorsed by the NRC on May 31, 2012 (Reference 6).
Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, utilized the guidance in Reference 5 to complete the Requested Actions for Recommendation 2.3, Seismic, for Prairie Island Nuclear Generating Plant (PINGP) Units 1 and 2. By letters dated November 26, 2012 (References 2 and 3), NSPM submitted the required seismic walkdown reports for PINGP Units 1 and 2 in response to the 10 CFR 50.54(f) information request.
Following the NRC Staff's initial review of the industry's walkdown reports, regulatory site audits were conducted at a sampling of plants. Based on the walkdown report reviews and site audits, the NRC Staff identified, in Reference 4, the additional information necessary to allow the NRC Staff to complete its assessments.
This enclosure provides the NSPM response to the RAis in Reference 4. This enclosure quotes each RAI in italics followed by the NSPM response.
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Enclosure NSPM Response to RAis Associated with Seismic Walkdowns 2.0 REQUESTS FOR ADDITIONAL INFORMATION AND RESPONSES NRC RAI-1: CONDUCT OF THE WALKDOWNS, DETERMINATION OF POTENTIALLY ADVERSE SEISMIC CONDITIONS, 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.
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Enclosure NSPM Response to RAis Associated with Seismic Walkdowns The NRC staff a/so found that the process that was used to deal with a field observation that was deemed to be a PASC was a/so not completely described or captured in the report. In many cases, the licensee reported that an LBE was not performed. 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 self-assessments conducted by the licensees of the audited plants a/so 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.
A/so, 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.
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Enclosure NSPM Response to RAis Associated with Seismic Walkdowns (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.
NSPM Response RAI-1:
Process As originally described in References 2 and 3, Section 5.1, the Seismic Walkdowns and Area Walk-Bys were conducted by two-person teams of trained Seismic Walkdown Engineers (SWE). The walkdowns and walk-bys were completed in accordance with Reference 5. The SWEs used engineering judgment, based on their experience and training, to identify conditions that could be PASCs.
These conditions were noted in the Seismic Walkdown Checklists (SWC) or Area Walk-by Checklists (AWC) as observations, and were then reviewed by site engineering to determine whether or not the issues could be readily shown to meet the seismic licensing basis. Consistent with Section 4 of Reference 5, the engineers were provided the latitude to rely upon new or existing analyses, where needed, to inform their judgment. If it was clear that the observations noted by the SWEs were not PASCs, then the observation was dispositioned as needing no further action. However, if site engineering could not readily determine if the condition met the seismic licensing basis, then the observation was dispositioned by entering the observation into the CAP to determine if the condition was a PASC.
Documentation Table 5-2 and Table 5-3 in Section 5, Seismic Walkdowns and Area Walk-Bys, of References 2 and 3 provided a summary of the observations identified during the seismic walkdowns and area walk-bys that were entered into the CAP or work management system. All of the observations entered into the CAP were assessed for operability and then reviewed to determine whether or not the conditions were PASCs.
It was concluded that the specific conditions of concern would not prevent the associated equipment from performing its safety-related function(s). None of the concerns identified by the SWEs during the walkdowns were judged to be PASCs that could affect the safety-related functions of equipment, and therefore, no licensing basis evaluations were performed. Observations that were entered into the work management system for resolution were conservatively included in Table 5-2 and Table 5-3 for tracking purposes. These observations did not require entry into the CAP, because it was readily determined (utilizing judgment, simple analysis or existing plant documentation) that the conditions were not seismic concerns.
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Enclosure NSPM Response to RAis Associated with Seismic Walkdowns Table F-1 and Table F-2 in Appendix F, Disposition of Seismic Walkdown Observations, of References 2 and 3, listed the observations identified in the SWCs and AWCs, and how each observation was dispositioned. Only those observations that required additional review by site engineering were included in these tables. Comments or recommended enhancements were not included. If an observation was entered into the CAP, or into the work management system, then a status of the action requested was provided.
Confirmation of Reported Information In order to confirm that the reported information supports concluding that the plant meets the current licensing basis, NSPM followed "Alternative (c)" of this RAI. A detailed review of the SWCs, AWCs and the Tables in References 2 and 3 was performed. No new conditions were identified that would require additional CAP entries or an additional supplement to the tables and text provided in the Reference 2 and 3 reports. All 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 Reference 2 and 3 reports to the NRC.
NRC RAI-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.
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Enclosure NSPM Response to RAis Associated with Seismic Walkdowns NSPM Response RAI-2:
NSPM has confirmed that the requested information was provided in the original Reference 2 and Reference 3 submittals, as described below.
(a) NSPM has confirmed that the following activities, described on page 6-1 of the Reference 5 walkdown guidance, were assessed as part of the peer review process. These activities were also described in Section 8 of References 2 and 3.
- Review of a sample of the checklists prepared for the Seismic Walkdowns and Area Walk-Bys
- Review of Licensing Basis Evaluations, as applicable
- Review of the decisions for entering the potentially adverse conditions into the CAP process
- Review of the submittal report
- Provide a summary report of the peer review process in the submittal report A summary of the activities completed as part of the PINGP peer review is provided in Appendix E, Peer Review Report, of References 2 and 3.
(b) A summary of the peer review process and activities completed for the PINGP seismic walkdowns was provided in Section 8, Peer Review Process, and Appendix E, Peer Review Report, of References 2 and 3.
Section 3, Personnel Qualifications, of References 2 and 3 describes the qualifications of personnel involved with the PINGP seismic walkdowns. As noted in Table 3-1 of this section, the peer reviewers were independent of the individual tasks being reviewed. For example, D. Cherlopalle is listed as both a Seismic Walkdown Engineer (SWE) and Peer Reviewer in Table 3-1 (References 2 and 3). However, as noted below the table, D. Cherlopalle only performed the peer review of the SWEL equipment selection process. He was not involved in this selection process, and therefore, he did not peer review any of the activities that he was involved with. Independent individuals from S&A were used to peer review the activities associated with the seismic walkdown inspections.
3.0 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, ADAMS Accession No. ML12056A046.
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Enclosure NSPM Response to RAis Associated with Seismic Walkdowns
- 2. NSPM Letter to NRC, "PINGP Unit 1 -Final 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, ADAMS Accession No. ML12334A495.
- 3. NSPM Letter to NRC, "PINGP Unit 2 - Final 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, ADAMS Accession No. ML12334A470.
- 4. NRC Letter, "Request for Additional Information Associ;3ted with Near-Term Task Force Recommendation 2.3, Seismic Walkdowns," dated November 1, 2013, ADAMS Accession No. ML133048418.
- 5. EPRI Technical Report 1025286, "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic," dated June 2012.
- 6. NRC Letter, "Endorsement of Electric Power Research Institute (EPRI) Draft Report 1025286, 'Seismic Walkdown Guidance,"' dated May 31, 2012, ADAMS Accession No. ML12145A529.
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