ML20012C066

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Forwards Addl Info Re Natural Circulation Evaluation Program Rept,Per 900208 Telcon Request
ML20012C066
Person / Time
Site: Summer South Carolina Electric & Gas Company icon.png
Issue date: 03/09/1990
From: Bradham O
SOUTH CAROLINA ELECTRIC & GAS CO.
To: Hayes J
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9003200034
Download: ML20012C066 (2)


Text

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Jenkinsville, SC 29065 e:=-

Nucitar Operations (803) 345 4040 SCE&G

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March 9, 1990  !

Document Control Desk U. S. Nuclear Regulatory Commission Washington, D. C. 20555

-Attention: Mr. J. J. Hayes, Jr.

Subject:

Virgil C. Summer Nuclear Station Docket No. 50/395 Operating License No NPF-12 Natural Circulation Gentlemen:

On January 26, 1990, South'CarolinaElectric&GasCompany(SCE&G) submitted WCAP-12464, " Virgil C. Summer Nuclear Station Natural Circulation Evaluation Program Report," in order to resolve Branch Technical Position RSB 5-1. In a telecon on February 8, 1990, the NRC requested additional information to support resolution of this item. Attached please find the requested information. If additional information is required, please call.

Very truly yours, W

0. S. Bradham ,

L ARR/0SB: led Attachment c: D. A. Nauman/0. W. Dixon, Jr./T. C. Nichols, Jr.

E. C. Roberts R. V. Tanner R. L. Prevatte S. D. Ebneter J. B. Knotts, Jr.

J. J. Hayes, Jr. A. M. Monroe General Managers H. G. Shealy C. A. Price NPCF R. B. Clary NSRC K. E. Nodland RTS (NRR890008)

J. C. Snelson File (810.33) g0\

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%< . Attachment 1 to Document Control Desk Letter i, A ' ttarch 9,1990 Page 1 of 1 Question: What is the capacity of the Condensate Storage Tank (CST)? Is there another " clean" water source (e.g., cleaner than service water) available for emergency feedwater?

Answer: The capacity of the CST is 500,000 gallons and the tank is normally maintained around 400,000 gallons. Per Technical Specifications, the minimum allowable volume in the tank is 172,700 gallons (whichprovides/protectstheminimumrequired design volume for emergency feedwater). The normal, safety-related backup for the CST emergency feedwater supply is the Service Water System. As discussed in the telecon, the Demineralized Water System may be available to provide additional " clean" water for the CST. The Demineralized Water Tank has a 500,000 gallon capacity and filling the CST from the Demineralized Water System is covered in procedure E0?-

1.3, " Natural Circulation Cooldown." However, the Demineralized Water System was not taken credit for in WCAP-12464 because it is not a safety-related system.

Question: Please address the difference in boration time between V. C.

Summer Nuclear Station (VCSNS) and Diablo Canyon. Confirm that sufficient capability exists to borate to cold shutdown l' conditions.

Answer: For VCSNS, the boration time in WCAP-12464 is 225 minutes to borate the system from 2000 ppm to 2300 ppm. This is based on a flowrate of 15 gpm via Reactor Coolant Pump (RCP) seal injection only. This time period is greater than the Diablo Canyon test results since Diablo Canyon used the Boron Injection Tank (20,000 ppm) and the Safety injection System to

, borate. Subsequently, the Diablo Canyon Charging System was l_ aligned to deliver flow to the seal injection lines and-the l normal charging line. At VCSNS, the operator would normally borate via the charging path if it is available. However, for the WCAP report, the seal injection path was chosen for boration as a minimum case to demonstrate that sufficient-l boration flow is available to achieve cold shutdown conditions. The-VCSNS design has sufficient capability to borate the Reactor Coolant System (RCS) to cold shutdown conditions while performing a natural circulation cooldown.

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