ML19347D501

Advises That Encl Page 15.2-22b in FSAR Amend 24 Was Mistakenly Renamed & New Page 15.2-22b Was Added.Renamed Page Will Be Added to FSAR in Next Amend to Bridge Info Currently on Pages 15.2-22b & 15.2-23

ML19347D501
Person / Time
Site:	Summer
Issue date:	03/20/1981
From:	Nichols T SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8103260275
Download: ML19347D501 (2)

Text

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Mr. Harold R. Denton, Director / Office of Nuclear Reactor Geulation bi If,%%g 4

                                                                                                              .s U. S. Nuclear Regulatory Commission                                      Q              /

Washington, D. C. 20555 4Q \

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 Boron Dilution Event - FSAR

Dear Mr. Denton:

In FSAR Amendment 24. the attached page 15.2-22b was mistakenly renamed and a new page 15.2-22b was added. The page which was renamed will be added back into the FSAR in the next amendment to bridge the information currently found on pages 15.2-22b and 15.2-23. If you have any questions, please let us know. Very truly yours, T. C. Nichols, Jr. RC:TCN:pj Attachment I CC: V. C. Summer w/o att. l G. H. Fischer w/o att. ! T. C. Nichols, Jr. w/o att. C. A. Price D. A. Nauman ! W. A; Williams, Jr. i R. B. Clary A. R. Koon A. A. Smith. H. N. Cyrus J. B. Knotts, Jr. J. L. Skolds B. A. Bursey O. S. Bradham ISEG NPCF/Whitaker File PRS 8108260,275 j

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Dilution flow is assumed to be a naximirm of 150 gpm, which is the capability of one primary water ir.akeup pump to deliver unborated p, (' ) water to the PCS, A mininum RCS water volume of 5000 ft3 is used. This is a conser-vative estimate of the active RCS volume with one reactor coolant 23 s , pump operating.

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4. Dilution During Startup T Prior to startup, the RCS is filled with borated water at a bcron

      . ,/                           -

concentration of 1555 ppa. This is a conservative estimate with the reactor at a 1.77% Ak/k shutdown margin at 5570F, Core monitoring is by external BF3 detectors. Mixing of the reac- ' tor coolant is acce.nplished by operation of the reictor coolant pumps. High source range flux level ara all reactor trip alarms are effective. (, In the analysis, a conservatively high dilution flow capacity for the centrifugal charging pumps is considered (approximately 300 spm). A minimum volume of 7360 ft3 in the reactor coolant system 23 is used. This corresponds to the active volume of the RCS excluding

                 .       the pressurizer.

5. . Dilution During Full Power Operation 23 k'i th the unit at power _ and the RCS at pressure, the dilution rate is

( limited by the capacity of the charging valve (analysis is performed assuming two charging pumps are in operation although only 23 (? s_.

  -{f 15.2-22b                   AMENDM?.NT 23 J ant'ARY, 1981}}