ML20141M108

Advises That Groundwater Level Exceeded 109.0 Inch Mean Sea Level in Dewatering Well 8 on 920217.Caused by Failure of Sump Pump Control Circuit Protector.Final Rept on Groundwater Program Will Be Submitted by 920430

ML20141M108
Person / Time
Site:	Grand Gulf
Issue date:	03/27/1992
From:	Cottle W ENTERGY OPERATIONS, INC.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GNRO-92-00026, GNRO-92-26, NUDOCS 9204010121
Download: ML20141M108 (2)

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W. T Cottin March 27. 1992 U.S. Nuclear Regulatory Commission Mail Station P1-137 Washington, D.C. P.0555 Attentim: Document Control Desk

SUBJECT:

Grand Gulf Nuclear Station Unit 1 ,

Docket No. 50-416 License No. HPF-29 Groundwater Level Exceeds 109.0' MSL in Dewatering Well 8 GNR0-92/00026 3

Gentlemen: g Groundwater level readings at dewatering well 8 (DW-8) on February 17, 1992 indicated a level of 109.3 feet mean sea level (MSL). DW-8 is located near the southeast corner of the Radwaste Building. This occurrence of groundwater level exceeding 109.0 feet MSL is being reported as requested by your letter dated August 19, 1985 (MAEC-85/0284).

The increased groundwater level was caused by failure of the sump pump control circuit protector. This failed component prohibited the control circuit relay from supplying power to W sump pump when groundwater level reached the level switch setpoint. Th ump pump operated properly upon replacement of the protector.

DW-8's sump pump f ailed recently as reported on February 7,1992

.(GNR0-92/00031). -That pump failure would not have affected its control circuit protector. The protector is in a 12.0 volt circuit and the pump is  :

powered by a three phase 480 volt supply.  ;

An engineering study performed in 1985 concluded that groundwater levels ,

up to 114.5 feet MSL would not impair the structural integrity of Unit 1 builuings as previously submitted by letter dated February 14, 1985 (AECM-85/0035).

9204010121 DR 920327 ADOCK 0500 6 p? l(

SPRPTMAR - 1

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P March 27, 1992 GNR0-92/00026 Page 2 of 3 A groundwater program is presently evaluating issues cssociated with high groundwater levels. A final report of the groundwater program is scheduled for issuance by April 30, 1992.

Yours tru ,

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WTC/BAB/cg cc: Mr. D. C. Hintt Mr. J. L. Mathis Mr. R. B. McGehee Mr. N. S. Reynolds Mr. H. L. Thomas Mr. Stewart D. Ebneter Regional Administrator U.S. Nuclear Regulatory Commission Region 11 101 Marietta St., N.W., Suite 2900 Atlanta, Georgio 30323 Mr. P. W. O'Connor, Froject Manager Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3

, Washington, D.C. 20555 SPRPTMAR - 2 J