ML20029A668
| ML20029A668 | |
| Person / Time | |
|---|---|
| Site: | McGuire  |
| Issue date: | 02/25/1991 |
| From: | Tucker H DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20029A669 | List: |
| References | |
| TAC-79337, NUDOCS 9103010178 | |
| Download: ML20029A668 (2) | |
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hin it at einla?b!ill DUKE POWER February 25, 1991 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Subject : McGuire Nuclear Station Docket Nos. 50-369 and -370 Unit 1 Cycle 7 Moveable Incore Detector Thimble Reduction Technical Specification Submittal - Request for Additional Clarification Concerning Flux Map Margins (TAC'No. 79337)
Centlemen:
On February 22, 1991, a telephone conversatica was held between Duke Power Company and Lambros Lois and Margaret Chatterton of the NRC regarding additional clarification cf the flux map data presented in our submittals of December 19, 1990 and February 15, 1991. The purpose of this letter is to document that conversation and provide information requested by the NRC, Prior to flux map 28, no L(Z) penalty due to the error discovered in Westinghouse EC:S analyses was necessary because sufficient margin to PCT of 2200F existed. A plant modification involving the recidual heat removal / low pressure injection pump minimum flow lines 'as performed prior to map 28 which used up the available PCT marg /K(Z) ratio in and required that we implement the Westinghouse L(Z) penalty. The F9 increased between maps 27 and 28, and also between ma is 30 and 39.
This increase required an additional 2% penalty to be appl ed to the measured F resulting in a reduction of the Power-AFD limits.
g From the attached Table 1, it can be seen that the mtximum measured F is very flat inthecyclewithrecentchangesbetwe.nmapsoflessthOn 1%.
It appears that the peak F has now been reached and for the n
remainder of the cycle we can cRpect a 2% margin <.ven after applying the 5.1% L(Z) penalty without reducing the Power-AFP limits. There is sufficient margin to accommodate large paaking increases if necessary by reducing the AFD limits. The Westinght,use aralysis which supported the proposed Technical Specification amendment it; applicable for the remainder of McGuire Unit 1 Cycle 7.
lf you have any questions, please call L.J. Rudy at (704) 373-3413.
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n Document Control Desk February 25, 1991 Page 2-Very truly yours.
- A ll.B.- Tucker, Sr. Vice President, Nuclear 1.JR/s xc Mr. S.D. Ebneter Regioral Administrator U.S. NLalear Regulatory Commission Region II 101 Marietta St., NW, Suite 2900 Atlanta, Georgia 30329 Mr. Dayno Brown, Chief Radiation Protection Branch Division of Facility Services Department of Iluman Services 701 Barbour Drive Raleigh, N.C. 27603-2008 Mr. T. A. Hood, Project. Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Mr. P.K. VanDoorn NRC Senior Resident Inspector McGuire Nuc ;.ar Sistion
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