ML20204A273

Informs That Setpoint for Automatic Transfer of HPCS Suction Acceptable for Listed Reason,Based Upon Data Obtained from Resolution of USI A-43,per Util 860215 Response

ML20204A273
Person / Time
Site:	Grand Gulf
Issue date:	04/25/1986
From:	Butler W Office of Nuclear Reactor Regulation
To:	Kingsley O MISSISSIPPI POWER & LIGHT CO.
References
REF-GTECI-A-43, REF-GTECI-ES, TASK-A-43, TASK-OR TAC-60736, NUDOCS 8605090555
Download: ML20204A273 (4)

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o UNITED STATES.

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NUCLEAR REGULATORY COMMISSION h

.E WASHINGTON. D. C. 20555 APR 85 W Docket No. 50-416 Mr. Oliver D. Kingsley, Jr.

Vice President, Nuclear Operations Mississippi Power & Light Company P.O. Box 23054 Jackson, Mississippi 39205

SUBJECT:

GRAND GULF UNIT 1 - SETPOINT FOR AUTOMATIC SWITCH 0VER OF HIGH PRESSURE CORE SPRAY (HPCS) SUCTION By letter dated February 15, 1986, Mississippi Power & Light Company responded to questions raised by the NRC staff regarding the setpoint for the HPCS suction i

transfer from the condensate storage tank to the suppression pool. The set l

point of 1 foot - 7.5 inches above the tank bottom is about 0.75 feet above the suction pipe intake. One of these questions related to the design adequacy of the suction transfer set point and vortex breaker to prevent significant air ingestion before the transfer to the suppression pool was completed. Another question involved administrative control of the condensate storage tank (CST) level.

1 The staff has reviewed the Mississippi Power & Light Company's submittal. The i

staff utilized experimental data obtained during the resolution of USI A-43 (e.g., NUREG-0897, Rev. I and NUREG/CR-2759) as the basis for determining the design adequacy of the suction pipe intake hydraulics at the low submergence levels corresponding to the proposed switchover setpoint. The staff's evaluation indicates that adequate design margin exists at the 1 foot-7.5 inch transfer set point to avoid air ingestion.

With respect to the question regarding the administrative control of CST water level, the licensee indicated that administrative procedures are used to main-tain the CST water level above 24 feet to ensure an inventory of 170,000 gallons as required by Technical Specifications. Should the HPCS be initiated, the operator will manually transfer the HPCS suction to the suppression pool at an indicated CST water level of 6 feet.

If this administrative action fails to effect the transfer, the HPCS pump suction will automatically transfer from the CST to the suppression pool when the CST water level is 5'-4".

The automatic transfer is a back-up to the manual control and provides assurance of the HPCS operation.

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t 2-The staff concludes that the set point for automatic transfer of the HPCS suction is acceptable because there would be no significant air ingestion at this level. The staff further concludes that administrative procedures are an acceptable means for CST water level control.

Sincerely,

~i Walter R. Butler, Director BWR Project Directorate No. 4 Division of BWR Licensing cc: See next page 4

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Mr. Oliver D. Kingsley, Jr.

Mississippi Power & Light Company Grand Gulf Nuclear Staiton l

cc:

Robert B. McGehee, Esquire The Honorable William J. Guste, Jr.

Wise, Carter, Child, Steen and Caraway Attorney General P.O. Box 651 Department of Justice Jackson, Mississippi 39205 State of Louisiana Baton Rouge, Louisiana 70804 Nicholas S. Reynolds, Esquire l

Bishop, Liberman, Cook, Pern11 Office of the Governor and Reynolds State of Mississippi 1200 17th Street, N.W.

Jackson, Mississippi 39201 Washington, D. C.

20036 4

Attorney General i

i Mr. Ralph T. Lally Gartin Building i

Manager of Quality Assurance Jackson, Mississippi 39205-Middle South Services, Inc.

P.O. Box 61000 Mr. Jack McMillan, Director New Orleans, Louisiana 70161 Division of Solid Waste Management Mississippi Department of Natural Mr. Larry F. Dale, Director Resources Nuclear Licensing and Safety Bureau of Pollution Control Mississippi Power & Light Company-Post Office Box 10385 3

P.O. Box 23054 Jackson, Mississippi 39209 Jackson, Mississippi 39205 Alton B. Cobb, M.D.

Mr. R. W. Jackson, Project Engineer State Health Officer Bechtel Power Corporation State Board of Health j

15740 Shady Grove Road P.O. Box 1700 Gaithersburg, Maryland 20877-1454 Jackson, Mississippi 39205 Mr. Ross C. Butcher oresident Senior Resident Inspector Claiborne County Board of Supervisors U.S. Nuclear Regulatory Commission Port Gibson, Mississippi 39150 Route 2, Box 399 Port Gibson, Mississippi 39150 W. Ted H. Cloninger Vice President, Nuclear Engineering i

Regional Administrator, Region II and Support U.S. Nuclear Regulatory Commission, Mississippi Power & Light Company 101 Marietta Street, N.W., Suite 2900 Post Office Box 23054 Atlanta, Georgia 30323 Jackson, Mississippi 39205 Mr. J. E. Cross l

Grand Gulf Nuclear Station Site Director

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Mississippi Power & Light Company P.O. Box 756 Port Gibson, Mississippi 39150 Mr. C. R. Hutchinson GGNS General Manager Mississippi Power & Light Company Post Office Box 756 Port Gibson, Mississippi 39150 i

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.The staff concludes that the set point for automatic transfer of the HPCS suction is acceptable because there would be no significant air ingestion at this level. The staff further concludes that administrative procedures are an acceptable means for CST water level control.

Sincerely.

Odginal signed by Walter R. Butler, Director BWR Project Directorate No. 4 Division of BWR Licensing cc: -See next page DISTRIBUTION Docket File?

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