ML20058C362

Responds to NRC Request for Evaluation of Operator Response Time Assuming All Rods Withdrawn W/Reactor Head Unbolted & in Place at Onset of Inadvertent Boron Dilution During Refueling.Adequate Time Allowed for Operator Action

ML20058C362
Person / Time
Site:	Summer
Issue date:	07/19/1982
From:	Dixon O SOUTH CAROLINA ELECTRIC & GAS CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
References
NUDOCS 8207260326
Download: ML20058C362 (1)

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SOUTH CAROUN A EttcTmc & GAS COMPANY eoor u..cc.a. w.

Cotuusi A. SourH C uoue.A 29218 July 19, 1982

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• Nur L. an One sea r.ne.e Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Comnission Washington, D.C.

20555

Subject:

Virgil C. Summr Nuclear Station Docket No. 50/395 Boron Dilution

Dear Mr. Denton:

Per your request, the South Carolina Electric and Gas CcxTpany has evaluated the operator response t!me assuming ALL RODS WITHDRAhN with the

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reactor head unbolted and in place at the onset of an inadvertent boron 7

dilution during refueling. We would enphasize that because of our administrative control program and the physical constraints associated with reactor head detensioning the assumed plant configuration of ALL RODS WITHDRAWN is of low probability. However, utilizing the systen constraints as outlined in Chapter 15.2.4 and a predicted ALL RODS WITHDRAhN critical boron tumentreinn of 1367 ppn for cycle one, it is estimated that greater than 30 minutes is available between the high flux at shutcbwn alarm and the loss of all shutdown margin. This allows the operator adequate tim to recognize and terminate the event.

The information provided above ensures that the required operator response tina is not ccxtprcxnised in the ALL RODS WITHDRAWN configuration.

If you need any further assistance in the resolution of this matter, please do not 1.esitate to contact us.

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Very truly yours,

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n W O. W. Dixo, Jr.

GJT/jes cc:

V. C. Summr O. S. Bralham G. H. Fischer L. D. Shealy H. N. Cyrus A. R. Koon T. C. Nichols, Jr.

M. N. Browne Q C[

O. W. Dixon, Jr.

G. J. Braidick M. B. Whitaker, Jr.

J. B. Cookinham 9

J. P. O'Reilly F. K. Mangan H. T. Babb J. L. Skolds D. A. Nauman J. B. Knotts, Jr.

C. L. Ligon (NSRC)

B. A. Bursey W. A. Willianu, Jr.

NPCF

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