ML18283B383

Transmitting Interim Report of Reportable Deficiency Clogged Cooling Water Lines to RHR & Core Spray Pump Motor Bearing Coolers. Final Report Will Be Submitted When Plans to Correct Deficiency Are Completed & Approved

ML18283B383
Person / Time
Site:	Browns Ferry
Issue date:	05/24/1976
From:	Gilleland J Tennessee Valley Authority
To:	Moseley N NRC/RGN-II
References
Download: ML18283B383 (6)

Text

830 Power Building TENNESSEE VALLEY AUTHORITY CHATTANOOGA, TENNESSEE 31401 hlAY 24 IS)8 Hr. Norman C. Ifoseiey, Director Office of Inspection and Enforcement 8<tp .

gg~ I. 9 U,S, Nuclear Regulatory Commission Region II ~ Suite 818 Q)l Q 230 Peachtree Street,. %4 Atlanta, Genie 30303 Dear Hr. Hoseley BROllNS PERRY NUCLEAR PLANT UNIT 3 'EPORTABLE DEPICIENCY -

CLOGGED COOLING PATER LXNES TO RHR AND CORE SPRAY PIMP M)TOR BEARING COOLERS Initial report of the sub)ect reportable deHciency was made to G. R. Klingler, NRC-XE, Region II, on April 22, 1976. In compliance with paragraph 50,55(e) of '10 CPR Part 50, we submit the enclosed interim report of the deficiency. A finaL report will be submitted when plans to correct this deficiency are completed and approved.

Very truly yours ~

J, E, Gilleland Assistant thnager of Power Enclostire CC (Enc?osure)!

~ Dr. Z. Volgenau, Director OfHce of Inspection and Enforcement U.S. Nuclear Regulatory Commission washington, DC 20555

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, Equal Opportunity Employer

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ENCLOSUPZ BRANS FERRY NUCLEAR PLANT UNIT 3 CLOGGED COOLING WATER LINES TO RHR AiH)

CORE SPRAY PUMP MOTOR BEARING COOLERS DDR 230 INTERIM REPORT On April 22, 3.976, an initial report was made by telephone to NRC-OIE Inspector, G. R. Klinger, by T. N. Barkalae 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 completed..

Descri tion of Occurrence While conducting preoperationa1 test TVA-4, the actual flow rates in the emergency equipment cooling water (EECÃ) lines to the RHR 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. The lines involved. had, diameters of either 3/8 inch or

3. inch.

Cause of the Deficienc The E~J system is only used. during tests or when equipment it services is operated,. Therefore, the coo3.ing water lines contain stagnant water for long periods of time. Since the EECtl source is raw water fram 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 dea1ing with silty water. Also, a few lines contained asiastic clams which were a11 of about the same size. This indicates that they msy be able to grow in the system between flushings with chlorinated. water.

Safet 3.icat i.ons The EEL system provides cooling water to the standby di.esel generators, RHR and core spray equipment room environmenta1 coolers, RHR pump sea1 coolers, and. core spray thrust bearing coolers. Lin s to the latter two

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coolers were found. to be clogged.. These lines are the sma11est lines in the system and., therefore, are the easiest to clog. Camplete plugging of these lines would prevent cooling water from circulating through this part of the system. However, temperature measurements indicated. in the control room verify whether each cooler or heat exchanger in the affected. unit area is receiving adequate flaw of cooling water. Inadequate flow could, eventual.y lead. to failure of the core spray pumps and the RHR pumps.

0 Descri tion of Corrective Action All the check valves in the clogged. sections of the lines were removed.

and thoroughly cleaned. The lines were then backflushed. through the coolers. Tests conducted. after the lines were reassembled showed. adequate flow in al3. but one line to a core spray pump motor bearing cooler.

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

Means Taken to Prevent a Recurrence Final plans to correct this deficiency have yet to be completed, and.

approved..

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