L-PI-13-087, Proposed Resolution of the Remaining Seismic Walkdowns Associated with NRC Request for Information Pursuant to 10 CFR 50.54(f) Re Seismic Aspects of Recommendation 2.3 of Near-Term Task Force Review of Insights from Fukushima..
| ML13259A028 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 09/12/2013 |
| From: | Jeffery Lynch Northern States Power Co, Xcel Energy |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| L-PI-13-087 | |
| Download: ML13259A028 (9) | |
Text
(l Xcel Energy Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch, MN 55089-9642 SEP 1 2 2013 L-PI-13-087 10 CFR 50.54(f)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant, Unit 1 Docket No. 50-282 Renewed Facility Operating License No. DPR-42 PINGP Unit 1 -Proposed Resolution of the Remaining Seismic Walkdowns Associated with NRC Request for Information Pursuant to 10 CFR 50.54(0 Regarding the Seismic Aspects of Recommendation 2.3 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident
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. ML12053A340.
- 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 Recommendations 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. NRC Memorandum, "Summary of the May 7, 2013, Public Conference Call on the Delayed Inspection Items Associated with Japan Lessons-Learned Near-Term Task Force Recommendation 2.3 Seismic Walkdowns," dated June 5, 2013, ADAMS Accession No. ML13136A003.
- 4. NRC Memorandum, "Summary of the August 1, 2013, Public Conference Call on the Delayed Inspection Items Associated with Japan Lessons Learned Near-Term Task Force Recommendation 2.3 Seismic Walkdowns," dated August 14, 2013, ADAMS Accession No. ML132188361.
Document Control Desk Page 2
- 5. EPRI Technical Report 1025286, "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic," dated June 2012.
On March 12, 2012, the NRC Staff issued Reference 1 to all Nuclear Regulatory Commission (NRC) power reactor licensees and holders of construction permits in active or deferred status. Enclosure 3 of the March 12, 2012 letter contained specific Requested Actions, Requested Information, and Required Responses associated with Near-Term Task Force (NTTF) Recommendation 2.3, Seismic.
On November 26, 2012, Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, submitted the required final response (Reference 2) to the Requested Information to NTTF Recommendation 2.3, Seismic (Enclosure 3 to Reference 1). The letter included an enclosure titled, "Prairie Island Nuclear Generating Plant - Unit 1, NTTF Recommendation 2.3 -Seismic Walkdown Report," that contained the results of the external seismic walkdowns completed for Prairie Island Nuclear Generating Plant (PINGP) Unit 1. Reference 2 included a commitment to complete the walkdowns of inaccessible components, including the internals of certain electrical cabinets or panels, by the second refueling outage after the initial walkdowns (Refueling Outage 1R30).
The schedule for completing the inaccessible walkdowns was based on the next planned refueling outage that provided an opportunity to inspect the internals of electrical equipment, considering the existing plant-specific component outage maintenance schedules. NSPM did not schedule additional unplanned equipment outages to support these cabinet interior inspections since NRC/industry guidance did not require circuits to be interrupted or disconnected to gain access to the interior portions of the cabinet.
The NRC scheduled a public conference call on May 7, 2013 to discuss NRC staff concerns regarding delayed inspection items as identified in seismic walkdown reports for a number of operating reactors (Reference 3). During the meeting, the NRC staff stated its expectation that walkdown activities should be completed as expeditiously as possible and by the next refueling outage, if possible. The NRC staff requested that licensees voluntarily submit a supplemental letter to their walkdown reports to propose an alternate approach for completing the inaccessible walkdowns by the next refueling outage. Another public conference call was scheduled on August 1, 2013 for the NRC staff to provide further clarification on the information that should be provided in the licensee's voluntary letters (Reference 4).
As requested in References 3 and 4, this letter provides NSPM's proposal for final disposition of the remaining NTTF Recommendation 2.3 Seismic Walkdowns for PINGP Unit 1. NSPM has accelerated the deferred seismic walkdown schedules by reviewing the remaining walkdown scope for opportunities where walkdowns could be done at an
Document Control Desk Page 3 earlier date based on current planned maintenance activities. Additionally, substituting current Seismic Walkdown Equipment List 1 (SWEL 1) components with alternate components that will be available for inspection by the next refueling outage was evaluated. The proposal for final disposition of the remaining seismic walkdowns, including an evaluation of component substitution and a detailed breakdown for expected completions of the deferred SWEL 1 items and the internal cabinet inspections, is provided in the enclosure to this letter.
Based on the summary of the status of the deferred seismic walkdowns for PINGP Unit 1 described in the enclosure to this letter, NSPM has determined that the NTTF Recommendation 2.3 Seismic Walkdowns for PINGP Unit 1 will be complete upon performance of the inspections described in the enclosure to this letter.
NSPM anticipates NRC concurrence with the proposed approach to achieve closure of the NTTF Recommendation 2.3 Seismic Walkdowns for PINGP Unit 1. This approach is justified based on the satisfactory results of the large number of walkdown inspections completed to date and the conclusion that a representative sampling of affected components has been achieved. Therefore, NSPM concludes that the intent of the NRC-endorsed Electric Power Research Institute (EPRI) Guidance (Reference 5) has been met.
The letter revises the commitments made in the Reference 2 seismic walkdown report.
In an effort to expedite the completion of the seismic walkdowns, NSPM will complete the Seismic Walkdowns of the inaccessible components listed in the enclosure of this letter by the end of Refueling Outage (RFO) 1R29, which is scheduled to start in Fall 2014. NSPM will provide an updated seismic walkdown report with the results of the walkdowns of the inaccessible components 60 days following the end of RFO 1R29.
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 revises two existing commitments from Reference 2, as follows.
Regulatory Commitments Revised Due Date NSPM will complete the Seismic Walkdowns of the Refueling Outage inaccessible components listed in the enclosure of this (RFO) 1R29 letter.
NSPM will provide an updated seismic walkdown report 60 days following with the results of the walkdowns of the inaccessible the end of RFO components. 1R29
Document Control Desk Page4 I declare under penalty of perjury that the foregoing is true and correct.
Executed on o 9}; .:2--/.:2 o J .7 d~ .Lynch Site 1ce President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure cc: Administrator, Region Ill, USNRC Director of Nuclear Reactor Regulation (NRR), USNRC Project Manager, PINGP, USNRC Resident Inspector, PINGP, USNRC
L-PI-13-087 NSPM Enclosure ENCLOSURE Prairie Island Nuclear Generating Plant- Unit 1 Seismic Walkdown Deferred Inspection Evaluation 1.0 Introduction Northern States Power Company, a Minnesota corporation (NSPM), d/b/a Xcel Energy, submitted a list of the inaccessible items that were deferred either for containment entry or cabinet internal inspection in Table D-1 of the November 26, 2012 report (Reference 1). NSPM originally committed to complete the seismic walkdowns of the inaccessible components by the end of Refueling Outage (RFO) 1R30. However, during public meetings in May and August 2013, the Nuclear Regulatory Commission (NRC) Staff requested that licensees voluntarily submit a supplemental letter to their walkdown reports to propose an alternate approach for completing the inaccessible walkdowns by the next refueling outage, 1R29. This enclosure provides a proposed approach for an expedited final disposition of the remaining Near-Term Task Force (NTTF)
Recommendation 2.3 Seismic Walkdowns for Prairie Island Nuclear Generating Plant (PINGP) Unit 1, as well as the justification for the proposed approach.
2.0 Proposed Disposition of Deferred Seismic Walkdowns In an effort to complete the deferred seismic walkdowns by the end of the next RFO, NSPM evaluated component availability to determine opportunities where the equipment could be accessible for inspection, as well as to determine viable substitutions that could be made to allow earlier inspection. As a result of this evaluation, two (2) component substitutions were made. One (1) substitution was made for Seismic Walkdown Equipment List 1 (SWEL 1) item BUS 122, because this component will not be out of service during the next RFO to allow an internal cabinet inspection. BUS 112 will be de-energized during the next RFO, and will be substituted for BUS 122 to allow for an internal cabinet inspection. The second substitution was made for SWEL 1 item BUS
- 16. BUS 16 is not scheduled to be out of service during the next RFO to allow an internal cabinet inspection. However, BUS 15 will be out of service during the next RFO, and will be substituted for BUS 16. With these two (2) substitutions, all Seismic Walkdowns will be completed by the end of the next RFO, 1R29.
For 480V Motor Control Centers (MCCs), NSPM determined that none of the 480V MCCs selected in SWEL 1 are currently planned to be out of service in the next RFO.
For personnel safety reasons and operational constraints, internal cabinet inspections of individual compartments of the MCCs will not be performed. No similar components will be available for substitution. Therefore, NSPM proposes to perform partial inspections of the 480V MCCs. Due to the fact that MCC anchorage can be accessed by removing panels at the bottom of the MCC that does not result in exposing energized conductors, NSPM will perform a visual inspection of the MCC's anchorage. An outage is not required to perform the visual inspections of the MCC anchorage.
For lower voltage cabinets (e.g., 120 VAC distribution panels), NSPM will perform a visual inspection of the component consistent with the process described in the NRC-endorsed Electric Power Research Institute (EPRI) Guidance (Reference 2). The panel faceplate will be removed to allow visual inspection of the anchorage and cabinet internals while the component is energized. If wires or other internal components block Page 1 of 5
L-PI-13-087 NSPM Enclosure the view of any anchors, they will not be moved to permit inspections. The operational and personnel safety risk do not justify movement of internal components within energized equipment. NSPM's procedures on electrical safety allow qualified individuals to approach energized electrical components, if the individuals do not cross the specified approach boundary distance for the particular component. The approach boundary for low voltage cabinets will allow visual inspection of the cabinet interiors without impacting personnel safety.
3.0 Justification for Substitutions Two electrical equipment substitutions were made with other safety related equipment.
The substitutions were made with other components that are within the power block at locations similar to the original electrical equipment. Therefore, the environmental and location diversity remains similar. Additionally, BUS 122 and BUS 112 are the same class of equipment and are from the same system, and BUS 15 and BUS 16 are the same class and from the same system. Therefore, the diversity and representation from every equipment class reported in the original SWEL 1 in Table A-3 of Reference 1 is not impacted by this change.
4.0 Justification for Partial Inspections of MCCs While NSPM will not complete internal cabinet inspections of five (5) deferred 480V MCC SWEL 1 items, a sufficient number of internal cabinet inspections will be completed to provide a representative sample of internal cabinet conditions at the site.
The electrical cabinets that will be and have been internally inspected are seismically designed electrical equipment being maintained using similar plant procedures and personnel, and therefore the conditions in these other electrical cabinets, with respect to configuration and degradation, are expected to be similar and representative of the 480V MCCs.
For the internal cabinet walkdown inspections that have been performed to date, the inspection findings have been limited to non-consequential and foreign material exclusion type concerns. No adverse seismic conditions have been identified (see Table 5-2 of Reference 1).
Based on the satisfactory results of the 11 internal cabinet inspections completed thus far, NSPM concludes that a representative sampling of affected components has been achieved; and thereby, the intent of the NRC-endorsed EPRI Guidance (Reference 2) has been met.
5.0 Current Status of Deferred Seismic Walkdown Items The current status of the deferred seismic walkdowns of inaccessible components, identified in Table D-1 of Reference 1, is given in Table 1 below. Note that SWEL 1 item 053-481 was mistakenly not identified in Table A-3 of Reference 1 as being a deferred Seismic Walkdown. However, 053-481 is appropriately identified as a deferred Seismic Walkdown, and is listed as such in Table D-1 of Reference 1.
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L-PI-13-087 NSPM Enclosure Table 1 -Status of Deferred Seismic Walkdowns for PINGP Unit 1 Substitute Equipment Substitute Completed Outage Description Equipment Notes Tag Description by 1R29 Required?
Tag D1 DSL GEN EXPANSION 053-481 TANK N/A N/A Yes No 075-012 122 CONT RM CHLR N/A N/A Yes No 11 BATT 11 BATTERY CHARGER N/A N/A Yes Yes CHG 11SFGDSSCRNHSEROOF Scaffolding 132-281 EXHT FAN N/A N/A Yes No Required 174-013 13 CNTMT FCU N/A N/A Yes Yes MN STM FR 11 STM GEN 1FT-464 N/A N/A Yes Yes CHNNL I RED F XMTR 1 PRZR (CHNL 111-BLU) LVL 1LT-428 N/A N/A Yes Yes XMTR 11 STM GEN LOOP A CHNNL 1LT-461 N/A N/A Yes Yes I RED LVL XMTR BUS 112 480V BUS 122 BUS 122 480V SWITCHGEAR BUS 112 Yes* Yes *Substitution SWITCHGEAR BUS 16 4.16KV BUS 15 4.16KV BUS16 BUS15 Yes* Yes *Substitution SWITCHGEAR SWITCHGEAR 11 CRDM SHRD CLG COIL CV-39405 N/A N/A Yes Yes SPLYCV MOTOR CONTROL CENTER Anchorage MCC 1A1 1A BUS 1 N/A N/A Yes No inspection only MOTOR CONTROL CENTER Anchorage MCC 1AB2 1AB BUS 2 N/A N/A Yes No inspection only MOTOR CONTROL CENTER Anchorage MCC 1K2 1K BUS 2 N/A N/A Yes No inspection only MOTOR CONTROL CENTER Anchorage MCC 1L2 1L BUS 2 N/A N/A Yes No inspection only MOTOR CONTROL CENTER Anchorage MCC 1T2 1T BUS 2 N/A N/A Yes No inspection only MTR 111F- 11 INVERTER (INSTR BUS II-N/A N/A Yes Yes 31 - - _y\/HI)
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L-PI-13-087 NSPM Enclosure Table 1 -Status of Deferred Seismic Walkdowns for PINGP Unit 1 Substitute Equipment Substitute Completed Outage Description Equipment Notes Tag Description by 1R29 Required?
Tag MTR 111F- 13 INVERTER (INSTR BUS Ill-N/A N/A Yes Yes 32 BLU) 14 FCU CLG WTR OUTL ISOL MV-32141 N/A N/A Yes Yes MVA Inspect while PNL 11 DISTRIBUTION PANEL 11 N/A N/A Yes No energized PNL 111 INSTR BUS II (WHI) PNL 111 N/A N/A Yes Yes INSTR BUS Ill (BLUE) PNL Inspect while PNL 113 113 N/A N/A Yes No energized Inspect while PNL12 DISTRIBUTION PANEL 12 N/A N/A Yes No energized AC DISTRIBUTION PANEL Inspect while PNL 133 N/A N/A Yes No energized 133 AC DISTRIBUTION PANEL Inspect while PNL 136 136 N/A N/A Yes No energized I
i Inspect while PNL 153 DISTRIBUTION PANEL 153 N/A N/A Yes No energized Inspect while PNL1EM DIST PNL 1EM N/A N/A Yes No energized 11 FCU DISCH TO CNTMT SV-33371 N/A N/A Yes Yes DOME CD-34072 SV U1 TRN A CHLD WTR/CLG SV-37460 N/A N/A Yes Yes WTR ISOL SV -** -
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L-PI-13-087 NSPM Enclosure 6.0 Summary NSPM will complete the Seismic Walkdowns of the inaccessible components listed above by the end of Refueling Outage (RFO) 1R29, scheduled to start in Fall2014.
NSPM will provide an updated seismic walkdown report with the results of the walkdowns of the inaccessible components 60 days following the end of RFO 1R29.
This letter revises the original regulatory commitments made in the seismic walkdown report dated November 26, 2012 (Reference 1). These commitments are being revised to facilitate an expedited schedule for completing the inaccessible walkdowns, as requested by the NRC.
The efforts described above will result in NSPM completing a sufficient number of SWEL 1 and internal cabinet inspection walkdown items to meet the intent of the NRC-endorsed EPRI Guidance document (Reference 2). The table below summarizes the percentage of the seismic walkdowns originally identified in the Reference 1 report that will be completed by the end of 1R29 (Fall 2014).
Total Internal Internal Cabinet Inspection Seismic Walkdowns to be Total SWEL Cabinet Items to be Completed by Completed by End of 1R29 1 Items Inspection End of 2014 Number I %Complete Items Number I %Complete 107 107 I 100% 31 26 I 84%
7.0 References
- 1. 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 Recommendations 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.
- 2. EPRI Technical Report 1025286, "Seismic Walkdown Guidance for Resolution of Fukushima Near-Term Task Force Recommendation 2.3: Seismic," dated June 2012.
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