ML20115A750

Special Rept:On 960624,both Diesel Fire Pumps Declared Inoperable.Caused by Injectable Sealant Matl Entering Service Water Sys.Performed Backwashing of Service Water Strainers

ML20115A750
Person / Time
Site:	LaSalle
Issue date:	07/03/1996
From:	Ray D COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9607080373
Download: ML20115A750 (2)

Text

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N Commonu calth I:diaon Company LaSalle Generating 5tation 1 2601 North 21st Road

. Starwilles, 11.61311-9757 )

Tel H15-3574761 l July 3,1996 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 This Special Report is submitted in accordance with LaSalle Unit 1 and 2 Operating Licenses NPF-11 and NPF-18, Appendix A, and Technical Specification 3.7.5.1 and 6.6.C.

Technical Specification 3.7.5.1 requires that the fire suppression water system shall be OPERABLE at all times with two OPERABLE fire suppress!on diesel driven fire pumps, each with a capacity of 2500 gpm, ,

with their discharge aligned to the fire suppression header.  !

l On Monday, June 24,1996, at 0927 both Diesel Fire Pumps (DFP) were l

declared inoperable due to cooling system fouling concems. While performing the fire pump surveillance as required by Technical ,

Specification 4.7.5.1.2.a.2.b, high motor temperature on the OB DFP was '

o'aserved and the DFP was manually shutdown. Elevated service water j strainer differential pressure on all three service water strainers was also l observed. The OA DFP had satisfactorily completed the surveillance I earlier that day but was subsequently declared inoperable as a

. precautionary measure based on the possibility of backflow into its heat exchanger. It is believed that injectable sealant material used for sealing cracks in the concrete flooring in the lake screen house had entered the Service Water system causing fouling of the DFP heat exchanger and a high differential pressure condition for the on-line service water strainers.

l Both reactor plants were reduced from 1100 MWe to approximately 850 MWe while operators performed backwashing of the service water strainers. At approximately 1140, the service water strainers had been successfully backwashed and the service water system pressure restored to normal.

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l In accordance with the ACTION statement for Technical Specification 3.7.5.1, within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> a backup fire suppression system, the Service Water system, was verified to be available. As stated in section 9.5 of the UFSAR and LaSalle County Station's response to FSAR question 10.47, l l water can be supplied from the Service Water system to the fire  ;

protection ring header through a 12"line, in addition, two Fire i Department pumpers rated at 1250 gpm @ 150 psi and 1000 gpm @ 150 l psi are on-site and are available to supplement the Fire Protection system should they be needed. These two pumpers are continuously manned by local fire department personnel and are connected to the ring header via two (2) 5" lines running from the pumpers to 2 outside hydrants.

Procedures are in place to operate the pumpers.

The schedule to retum the DFPs to OPERABLE status is contingent upon the subsequent strainer inspections / cleaning and testing of the DFPs.

This testing involves the performance of the weekly fire pump surveillance and a full flow test on the OB DFP.

! A root cause team was formed on June 24,1996, to investigate the service water system fouling. .

l If there are any questions or comments conceming this letter, please refer l them to me at (815) 357-6761, extension 2212.

l Respectfully, 1

J. Ray Station Manager LaSalle County Station cc: H. J. Miller, NRC Region ill Administrator P. G. Brochman, NRC Senior Resident inspector - LaSalle i

D. M. Skay, Project Manager - NRR - LaSalle l F. Niziolek, Office of Nuclear Facility Safety - IDNS l Central File i

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