ML20084J383

Ro:On 730130,RHR Pump 2C Discharge Check Valve Discovered Leaking.Caused by Piece of Wire Between Disc & Seat

ML20084J383
Person / Time
Site:	Quad Cities
Issue date:	02/06/1973
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	Giambusso A US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084J376	List: ML20084J372 ML20084J383
References
BBS-73-19, NUDOCS 8305120579
Download: ML20084J383 (2)

Text

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Outd Citi c' ear Pover Station Post Office Box 216

> @. Commo Cordova, Illinois 61242 Telephone 309/654-2241

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February 6,1973 idif.9 ei' ap .% Q *

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Mr. Angelo Giambusso Deputy Director for Reactor Projects Directorate of Licensing U. S. Atomic Energy Commission I Washington, D. C. 20545 j

Reference:

Quad-Cities Nuclear Power Station - Unit 2 License No. DPR-30, Docket No. 50-265 '

Sections 3 5.G.2 and 6.6.B.

Dear Mr. Giambusso:

' fI, r The purpose of this letter is to inform you of the details regarding an incident in which RHR pump 2C ' discharge check

[Jk valve was leaking. This incident wac reported to you by telegram on January 30, 1973 Lil DESCRIPTION OF THE INCIDENT qf On January 30, 1973, Unit 2 was operating at approximately 90 per cent power. At 2: 53 a.m. , RHR pump 20 was run in order p to pump down the water level in the pressure suppression chamber. At 3: 15 a.m. the pump was shutdown after the torus hhc level had reached zero on the control room level indicator.

At that time, it was observed that the RHR discharge header V ,30 pressure could not be maintained. The pump was re-started and shut down, and the same conditions prevailed as before.

All motor operated valves were checked, and verified oper-able, and in normal. position. The problem was pinpointed by closing the cross-tie between the t,wo RHR loops. When this was done, A loop held pressure and B loop did not.

The valve from the pressure suppression chamber to the 2C RHR pump suction, 2-1001-70, was closed, and pressure was maintained in the B loop. It was therefore determined that the 2C RHR pump discharge check valve 2-1001-67C was leaking j back and causing the B loop to lose pressure.

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• Mr. Angelo Giambusso February 6, 1973 INVESTIGATION AND CORRECTIVE ACTION RHR pump 2C was taken out of service to inspect the check valve and the required surveillance of Technical Specification

/ 3 5. A. 4 - was done . When the check valve was removed and

[ disassembled a piece of wire was discovered between the disc and seat _ .

' On February 1,1973, 2C RHR pump was returned to service, tested satisfactorily, and declared operable. The pressure in B loop was maintained by the ECCS Fill System af ter the pump was shutdown.

The origin of the wire could not be determined. A grinder arbor was also removed from the piping at the check valve however, it was not interfering with valve operation.

Although the RHR loop could not be pressurized with the leaking check valve, it is believed that the leakage could not have been large enough to affect the operability of ,

the -other 3 pumps at anytime. Even if the system were not filled- the RHRS would still perform its design function as stated in the Basis for Specification 3.5.G.

Very truly yours, COMMONWEALTH EDISON COMPANY Quad-Cities pucle r Power Station

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