ML20085E740

Interim Deficiency Rept Re Clogged Cooling Water Lines to RHR & Core Spray Pump Motor Bearing Coolers.Initially Reported on 760422.Check Valves Removed & Cleaned & Lines Backflushed.Final Plans Incomplete

ML20085E740
Person / Time
Site:	Browns Ferry
Issue date:	05/24/1976
From:	Gilleland J TENNESSEE VALLEY AUTHORITY
To:	Moseley N NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML20085E712	List: ML20085E740
References
10CFR-050.55E, 10CFR-50.55E, NUDOCS 8308160548
Download: ML20085E740 (3)

Text

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conjo, 830 Power Buildin gg FILE M' g- $ TENNESSEE VALLEY AUTHORITY

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Ore.3916 MAY 241976 ,'g' W /g

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Hr. Norman C. !!oseley, Director Office of Inspection and Enforcement #'s ., '

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U.S. !!uclear Regulatory Corrdnsion - "

Ecgion II - Suite 818 \

Eik'l1' 230 Peachtree Street,IN. '2, Atlanta, Georgia 30303

Dear lir. Moseley:

y/et0M'bs'N s BROIRIS FERRY NUCLEAR PLANT IRTIT 3 - REPORTABLE DEFICIENCY -

CLOGGED COOLING WATER LINES TO RHR'AND COP 2 SPPAY PUMP IOTOR BEARING COOLERS Initial report of the subject reportable deficiency was }

made to G. R. Klingler, NRC-IE, Region II, on April 22, 1976. In conpliance with paragraph 50.55(c) of 10 CFR Part 50, we subnit the enclosed interin report of the deficiency. A final report will be submitted when '

plans L. correct this deficiency are completed and approved.

Very truly yours, J. E. Gilleland Assistant Manager of Power i

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Enclosure j CC (Enclosure):

/ Dr. E. Volgenau, Director Office of Inspection and Enforcement ,g U.S. Nuclear Regulatory Cocanission Washington, DC 20555 8308160548 760712 PDR ADOCK 05000259 S PDR __

An Equal Opportunity Employer

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. , ENCLOSURE BRORNS FERRY NUCLEAR PLANT URIT 3 CLOGGED COOLIEG WATER LINES TO RHR AND CORE SPRAY PUMP MOTOR BEARING COOLERS DDR 230 INTERIM REPORT On April 22, 1976, an initial report was made by telephone to URC-0IE Inspector, G. R. Klinger, by T. W. Barkalow and S. H. Mindel. The report was made in compliance with 10CFR50.55(e). This is an interim report.  ;

A final report will be submitted once final plans to correct the deficiency are complete 1.

Description of Occurrence While conducting preoperational test TVA l , the actual flow rates in i the emergency equip:: lent cooling water (EECW) lines to the RER and core spray pump motor bearing coolers were found to be below those required by the test. An investigation revealed these lines to be clogged with mud and scale. Thelinesinvolvedhaddiametersofeither3/8inchor 1 inch.

Cause of the D2ficiency The EECW system is only used during tests or when equipment it services is operated. Therefore, the cooling water lines contain stagnant water fer long periods of time. Since the EECW source is raw water from Wheeler Reservoir, the stagnation leads to settlement of suspended solids and clogging in sections of lines at the lower elevations. The system does have strainers, but they have been ineffective in dealing with silty water. Also, a few lines contained asiastic clams which were all of about the same size. This indicates that they may be able to grow in the system between flushings with chlorinated water. ,

Safety Implications The EECW system provides cooling water to the standby diesel generators, RHR and core spray equipment room environmental coolers, RHR pump seal coolers, and core cpray thrust bearing coolers.. Lim a to the latter two ,

coolers were found to be clogged. These lines are tre smallest lines in the system and, therefore, are the easiest to cleg. Complete plugging of these lines would prevent cooling water from circulating through this part cf the system. However, temperature measurements indicated in the control room verify whether each cooler or heat exchsnger in the affected unit area is receiving adequate flow of cooling water. Inadequate flow could eventually lead to failure of the core spray pumps and the RHR pumps.

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o 2 Description of Corrective Action An the check valves in the clogged sections of the lines were recoved and thoroughly c1 caned. The lines were then backflushed through the coolers. Tests conducted after the lines were reassembled showed adequate flow in all but one line to a core spray pump motor bearing cooler.

This line will be disassembled and reflushed to remove any remaining blockage.

M:ans Taken to Prevent a Recurrence Final plans to correct this deficiency have yet to be completed and approved. ,

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