ML20077E789

Application for Amend to License NPF-17,increases Surveillance Interval for Weighing Ice from 9 Months to Next Refueling Outage (17 Months) Presently Scheduled for 920116

ML20077E789
Person / Time
Site:	Mcguire
Issue date:	06/05/1991
From:	Priory R DUKE POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20077E792	List: ML20077E789 ML20077E805
References
NUDOCS 9106110229
Download: ML20077E789 (3)

Text

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June 5,1991 '

l U. S. Nuclear Regulatory Commission i

A'ITN: Document Control Desk Washington, D. C. 20555

Subject:

McGuire Nuclear Station, Unit 2 Docket No. 50-370 Requested Technical Specification Changes (T.S. 3/4.6.5.1) i One Time Increase in Surveillance Interval for Ice Weighing Gentlemen:

Attached is a License Amendment Request to Appendix A, Technical Specifications (TS),

of Facility Operating License NPF-17 for McGuire Nuclear Station Unit 2. The requested amendment increases the surveillance interval for weighing ice from 9 months to the next refueling outage (~ 17 months) presently scheduled for January 16, 1992. This is a one time change that app i , to Unit 2 only.

The requested TS amendment will allow Duke Power to climinate the need for on-line ice weighing this year for the Unit 2 ice condenser which would otherwise be required to be l performed by August 3,1991. During ice weighing, the Ice Condenser baskets are twisted to ensure they are free from ice buildup and are not binding on the lattice steel suppon structure which could affect the accuracy of the measured weight. Duke Power has determined that this twisting of the ice baskets may possibly place undesirable loads on the 2 U bolt assemblies which secure the basket to its lower support structure, located at the bottom of each ice basket column. As previously documented in LER 369/90-28, these loading conditions are not typical of the design basis loading conditions in magnitude or geometry. The results of the metallurgical analysis performed on the failed U-bolts indicated that the maintenance techniques used to weigh the ice baskets may have propagated the cracks that originated in the U-bolts because of the manufacturing process.

i Since failure of the U bolts would render the respective ice condenser basket inoperable, 1

Duke requests that TS 3/4.6.5.1 be revised to extend the ice weighing surveillance interval from 9 months to the next Unit 2 refueling outage, to prevent an unnecessary shutdown of

, Unit 2. Current ice basket weights and actual Ice Condenser sublimation rates have been analyzed and determined adequate to ensure the safety analysis limits are not violated.

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U. S. Nuclear Regulatory Commission June 5,1991 Page 2 As presented to members of the NRC Staff by Duke personnel in a meeting held on May 22,1991, a modification to the present U-bolt assembly is planned to begin the next Unit 2 refueling outage (EOC 7). This replacement effort will take 4 outages to fully implement but subsequent mid-cycle surveillances will resume since the ice baskets to be weighed will have the new anchor assemblies. A copy of the slides presented at the meeting in White Flint are included in Attachment 4.

Attachment I contains the requested TS changes. Attachment 2 contains the background and technicaljustification to support the requested changes. Attachment 3 provides the analysis performed in accordance with 10CFR50.92 which concludes that the requested amendment does not involve a Significant Hazards Consideration.

Duke Power is forwarding a copy of this amendment request and Significant Hazards Consideration Determination to the North Carolina Department of Human Resources.

It is requested that the NRC Staff review and approve this requested amendment prior to Friday, August 2,1991. The current TS Surveillance period for Unit 2 expires on Saturday, August 3,1991, which includes the 25% extension allowed by TS 4.0.2.

Should there be any questions concerning this amendment request or if additional information is required, please contact Mr. David V. Ethington at (704) 373-2025.

Very Truly Yours, I '

R. B. Priory icesurvu/dve Attachments cc: S. D. Ebneter Regional Admittistrator, Region II Dayne Brown, Director Division of Radiation Protection T. A. Reed, ONRR P. K. VanDoorn Senior Resident inspector

4 U.S.NRC June 5,1991 Page 3 R. B. Priory, being duly sworn, states that he is Senior Vice President of Duke Power Company; that he is authorized on part of said company to sign and file with Nuclear Regulatory Commission this revision to the McGuire Nuclear Station License No. NPF-17 and that all statements and mr.tters set forth therein are true and correct to the best of his knowledge, r

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R. B. Priory, SeniorTice President Subwribed and sworn to before me this 5th day of June,1991.

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