L-PI-13-082, Proposed Resolution of the Remaining Seismic Walkdowns Associated with 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.
| ML13259A027 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 09/12/2013 |
| From: | Jeffery Lynch Northern States Power Co, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-PI-13-082 | |
| Download: ML13259A027 (9) | |
Text
(l Xcel Energy Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch, MN 55089-9642 SEP 12 2013 L-PI-13-082 10 CFR 50.54(f)
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant, Unit 2 Docket No. 50-306 Renewed Facility Operating License No. DPR-60 PINGP Unit 2- Proposed Resolution of the Remaining Seismic Walkdowns Associated with 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
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 2- 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. ML12334A470.
- 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. ML13218B361.
Document Control Desk Page2
- 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, 20121etter 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 2, 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 2. 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 2R29).
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 2. 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 2 described in the enclosure to this letter, NSPM has determined that the NTTF Recommendation 2.3 Seismic Walkdowns for PINGP Unit 2 will be complete upon performance of the inspections described in the enclosure of this letter.
NSPM anticipates NRC concurrence with the proposed approach to achieve closure of the NTTF Recommendation 2.3 Seismic Walkdowns for PINGP Unit 2. 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) 2R28, which is scheduled to start in Fall 2013. 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 2R28.
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) 2R28 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. 2R28
Document Control Desk Page4 I declare under penalty of perjury that the foregoing is true and correct.
Executed on ~>'7) 2 j..2c!J 13 d!e+/-::-
Site Vice 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-13-082 NSPM Enclosure ENCLOSURE Prairie Island Nuclear Generating Plant- Unit 2 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)0 NSPM originally committed to complete the seismic walkdowns of the inaccessible components by the end of Refueling Outage (RFO) 2R290 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, 2R28" This enclosure provides a proposed approach for final disposition of the remaining Near-Term Task Force (NTTF) Recommendation 203 Seismic Walkdowns for Prairie Island Nuclear Generating Plant (PINGP) Unit 2, 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, NSPM identified seven (7) components that will not be out of service during the next RFO (2R28) to allow for internal cabinet inspections" These seven (7) components were Seismic Walkdown Equipment List 1 (SWEL 1) items BUS 211, BUS 221, BUS 222, MCC 2A 1, MCC 2K1, MCC 2K2, and MCC 2L2" NSPM identified four (4) similar components that will be available in the next RFO (2R28) for inspection< For the 480V switchgear internal cabinet inspections, BUS 212 will be substituted for BUS 2110 SWEL 1 items BUS 221 and BUS 222 will be deleted from SWEL 1, because these components will not be accessible for walkdowns in the next refueling outage, 2R280 As for the 480V Motor Control Center (MCC) internal cabinet inspections, MCC 2LA 1 will be substituted for MCC 2A 1, and MCC 2M1 will be substituted for MCC 2K1" The other available 480V MCC, MCC 2X1, will be added to SWEL 1 as an additional walkdown inspection" For SWEL 1 Items MCC 2K2 and MCC 2L2, NSPM proposes to perform partial inspections of the 480V MCCso Even though internal cabinet inspections of individual compartments of the MCCs will not be performed due to personnel safety issues and operational constraints, NSPM will perform a visual inspection of the MCC's anchorage" 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, these visual inspections will include assessment of the MCC's anchorage" An outage is not required to perform inspections of the MCC anchorage" Page 1 of 5
L-PI-13-082 NSPM Enclosure For lower voltage cabinets (e.g., 120 VAC distribution panels), the panel faceplate will be removed to allow visual inspection of the anchorage and internals while the component is energized. If wires or other internal components block 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 The three electrical equipment substitutions were made with other safety related equipment. The substitutions were made with other electrical equipment that is within the power block at a location similar to the original electrical equipment. Therefore, the environmental and location diversity remains similar. Additionally, BUS 211 and BUS 212 are the same class of equipment and are from the same system. MCC 2LA1 and MCC 2M1 are also the same class of equipment and are from the same system as MCC 2A1 and MCC 2K1. Therefore the diversity and representation from every equipment class reported in the original SWEL 1 in Table A-2 of Reference 1 is not impacted by this change. While NSPM will not complete the Seismic Walkdowns of two (2) deferred 480V Bus Switchgear, the one (1) Seismic Walkdown of BUS 211 will provide a representative sample for the two (2) 480V Bus Switchgear that will not be inspected.
4.0 Justification for Partial Inspections of MCCs While NSPM will not complete the internal cabinet inspections of two (2) deferred 480V MCCs, three (3) internal cabinet inspections will be completed on other 480V MCCs. All of these MCC cabinets are similar and the three (3) available substitutes will provide a representative sample for the two (2) 480V MCCs that will not be inspected internally.
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, and the substitutes available for internal inspections, NSPM concludes that a representative sampling of affected components has been achieved; and thereby, the intent of the NRC-endorsed Electric Power Research Institute (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 the table below.
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L-PI-13-082 NSPM Enclosure Table 1 -Status of Deferred Seismic Walkdowns for PINGP Unit 2 Substitute Equipment Substitute Completed Outage Description Equipment Notes Tag Description by 2R28 Required?
Tag 50000 D5 DSL GEN BENCHBOARD N/A N/A Yes Yes 21 BATT 21 BATTERY CHARGER N/A N/A Yes Yes CHG 211NV 21 INVERTER N/A N/A Yes Yes 21 SFGDS SCRNHSE ROOF Scaffolding 232-281 EXHT FAN N/A N/A Yes No Required 258-011 21 CLG WTR STRNR N/A N/A Yes Yes 274-013 23 CNTMT FCU N/A N/A Yes Yes MN STM FR 21 STM GEN 2FT-464 N/A N/A Yes Yes CHNNL I RED F XMTR 2 PRZR (CHNL 111-BLU)LVL 2LT-428 N/A N/A Yes Yes XMTR 21 STM GEN LOOP A CHNNL 2LT-461 N/A N/A Yes Yes I-RED LVL XMTR 231NV 231NVERTER N/A N/A Yes Yes B25/LOAD BUS 25 SFGDS LOAD N/A N/A Yes Yes SEQ CAB SEQUENCER CABINET BUS 212 480V BUS 211 BUS 211 480V SWITCHGEAR BUS 212 Yes* Yes *Substitution SWITCHGEAR Cannot perform walkdowns in I BUS 221 BUS 221 480V SWITCHGEAR N/A N/A No Yes 2R28 - delete from SWEL 1 Cannot perform walkdowns in BUS 222 BUS 222 480V SWITCHGEAR N/A N/A No Yes 2R28 -delete from SWEL 1 BUS 26 4.16KV BUS 26 N/A N/A Yes Yes SWITCHGEAR 22 CRDM SHRD CLG COIL CV-39417 N/A N/A Yes Yes SPLY CV Page 3 of 5
L-PI-13-082 NSPM Enclosure Table 1 -Status of Deferred Seismic Walkdowns for PINGP Unit 2 Substitute Equipment Substitute Completed Outage Description Equipment Notes Tag Description by 2R28 Required?
Tag 21 CRDM SHRD CLG COIL CV-39419 N/A N/A Yes Yes SPLYCV MOTOR CONTROL CENTER MOTOR CONTROL MCC 2A1 MCC 2LA1 Yes* Yes *Substitution 2A BUS 1 CENTER 2LA BUS 1 MOTOR CONTROL CENTER MOTOR CONTROL MCC 2K1 MCC 2M1 Yes* Yes *Substitution 2K BUS 1 CENTER 2M BUS 1 MOTOR CONTROL CENTER Anchorage MCC 2K2 2K BUS 2 N/A N/A Yes No inspection only MOTOR CONTROL CENTER Anchorage MCC 2L2 2L BUS 2 N/A N/A Yes No inspection only MOTOR CONTROL CENTER Additional MCC 2X1 N/A N/A Yes Yes 2X BUS 1 walkdown 24 FCU CLG WTR OUTL ISOL MV-32156 N/A N/A Yes Yes MVA Inspect while PNL 21 DISTRIBUTION PANEL 21 N/A N/A Yes No energized INSTRUMENT BUS Ill PANEL Inspect while PNL 213 (BLU) 213 N/A N/A Yes No energized AC DISTRIBUTION PANEL Inspect while PNL 235 N/A N/A Yes No energized 235 DC DISTRIBUTION PANEL Inspect while PNL 253 253 N/A N/A Yes No energized Inspect while PNL2EM DISTRIBUTION PANEL 2EM N/A N/A Yes No energized 21 FCU DISCH TO CNTMT SV-33389 N/A N/A Yes Yes DOME CD-34080 SV U2 TRN A CHLD WTR/CLG SV-37464 N/A N/A Yes Yes WTRISOLSV UNIT 2 TRAIN A CHILL SV-37466 N/A N/A Yes Yes WTRICLG WTR ISOL SV Page 4 of 5
L-PI-13-082 NSPM Enclosure 6.0 Summary NSPM will complete the Seismic Walkdowns of the inaccessible components listed above by the end of Refueling Outage (RFO) 2R28, scheduled to start in Fall 2013.
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 2R28.
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 that will be completed by the end of 2R28 (Fall 2013). The total SWEL 1 items identified in Reference 1 was 94. However, NSPM plans to remove BUS 221 and BUS 222 from the SWEL 1, and add a Seismic Walkdown for MCC 2X1. These changes to SWEL 1 will result in a total of 93 completed Seismic Walkdowns.
Total Internal Internal Cabinet Inspection Seismic Walkdowns to be Total SWEL Cabinet Items to be Completed by Completed by End of 2R28 1 Items Inspection End of 2014 Number I %Complete Items Number I %Complete 93 93 I 100% 31 29 I 94%
7.0 References
- 1. 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 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. ML12334A470.
- 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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