ML20199C898
| ML20199C898 | |
| Person / Time | |
|---|---|
| Site: | Monticello  |
| Issue date: | 11/12/1997 |
| From: | Kim T NRC (Affiliation Not Assigned) |
| To: | Richard Anderson NORTHERN STATES POWER CO. |
| References | |
| REF-GTECI-A-46, REF-GTECI-SC, TASK-A-46, TASK-OR TAC-M69460, NUDOCS 9711200188 | |
| Download: ML20199C898 (6) | |
Text
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November 12, 1997 Mr. Roger O. Anderson, Director Licensing and Management issues Northern States Power Company 414 Nicollet Mall Min aapolis, Minnesota 55401 SUBJECY: MONTICELLO NUCLEAR GENERATING PLANT - REVISION TO STAFF REQUEST FOR ADDITIONAL INFORMATION RELATED TO UNRESOLVED SAFETY ISSUE (USI) A-46, SEISMIC EVALUATION REPORT (TAC NO. M69460)
Dear Mr. Anderson:
Enclosed is a revision to the NRC staffs previous, request for additional information dated October 8,1997, related to the subject USl A-46 seismic evaluation report. This revision adds three additional staff questions and extends the requested response date to January 15,1998, from December 19,1997.
As stated in the October 8,1997, letter, the NRC staff has reviewed Northern States Power (NSP) Company's April 29,1997, submittal related to the subject USI A-46 seismic evaluation report. The scope of the staffs review included structural engineering, integrity of anchor bolts, and seismic analysis issues. Additional information, as discussed in the enclosure, is requested in order for the staff to complete its review. NRC requests that NSP respond by January 15, 1998.
As a pa t of the overall USl A-46 review effort, the staff may conduct an onsite audit of the seismic evaluation report, related appendices, engineering calculations including, Screening Evaluation Work Sheets and Outlier Seismic Verification Sheets, and specific methods used in resolution of key outliers.
If you have any questions concerning this request, please contact me at 301-415-1392.
c 5
Sincerely, ORIGINAL SIGNED BY Tae Kim, Senior Project Manager Project Directorate lil 1 Division of Reactor Projects Ill/IV Office of Nuclear Reactor Regulation i
Docket No. 50-263 Dfol
cedures.
c.
Describe the typical configurations of your ductile raceways (dimension, member ssze, supports, etc.)
d.
Justify the position that ductile raceways need not be evaluated for horizontalload.
When a reference is provided, state the page number and paragraph. The reference should be self contained, and not refer to another reference.
e.
In the i valuation of the cable tmys cnd raceways, if the ductility of the attachments is assv ved in one horizontal direction, does it necessan'ly (cllow that the same system is ductile in the perpendicular direction? If yes, provide :he basis of this conclusion. Ifit is not ductile in the perpendicular direction, how was the seismic adequacy of the attachmerats evaluated ?
I 1.
Discuss any raceways and cable trays including supports in your plant that are outside of the experience data. Explain what criteria are used for establishing their safety adequacy end specifyyourplan for resolution of outliers that did not meet the acceptance criteria. Provide examples of the configurations of such raceways and cable trays including supports. Also, indicate the percentage of cable trays and raceways outside the experience data in relation to the population of raceways and cable trays axamined during the walkdowns of the safe shut down path, How are they going to be evaluated and d.sposed?
1
l 4
g.
Submli the evaluation and analysis results for four of the representative sample raceways (one single non-ductile, one single ductile, one multiple non-ductile, and one multiple c'uctile raceway), including the configurations (dimension, member size, supports, etc.).
9 In Reference B, the staff had specifically requested the analytical calculations for the resolution of outliers. The NSP's response (Reference A) did not provide the analytical calculations. Rather, the NSP requested the NRC staff to review the material at the Monticello site. The staffis requesting the NSP to provide the analytical calculations for relief valves RV-4236 and RV-4673, Tanks T-45A and T-458. After a revies of the calculations, the staff will determine the necessity for an audit at Monticello.
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