ML19210B383

Deficiency Rept Re Partial Draining of RCS from 150 Inches to Near 0 Inches Pressurizer Level(Approx 40000 Gallons). Caused by Personnel Error.Operator Closed DH-V6A Valve. Plant Shut Down W/No Testing in Progress

ML19210B383
Person / Time
Site:	Three Mile Island
Issue date:	12/04/1973
From:	John Miller METROPOLITAN EDISON CO.
To:
References
NUDOCS 7911070705
Download: ML19210B383 (2)

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%,, - ,', ,.xam METROPOLITAN EDISON COMPANY uss c:arvor ce:cmeucucuriunescavouricv j POST OFFICE SOX 542 REAotNG, PENNSYLVANI A 19603 TELEPHONE 215 - 929 4601 December h, 1973 Dr. D. R. Knuth, Director Directorate of Regulatory Operations United States Atomic Energy Cot: mission Washington, D. C. 20545

Subject:

Three Mile Island Nuclear Station Unit 1 Docket No. 50-289

• Partial Draining of Reactor Coolant System

Dear Dr. Knuth:

You were notified on October 25, 1973, of a situation which may be con-sidered reportable under 10CFR50.55(e), " Conditions of Construction Permits".

This situation related to a partial draining of the Reactor Coolant System.

DESCRIPTION OF INCIDENT The plant was in a startup and testing phase with no major systems in operation. The Reactor Coolant System was filled, vented and pressurized with approximately 42 pounds of nitrogen.

The Shift Foreman had instructed the Control Rocm Operator (an upgraded Auxiliary Operator) to align specific valves in the Decay Heat Removal System in preparation for processing the water in the Reactor Coolant System through the Liquid Waste Disposal System precoat filters. The operator was given a hands.ritten instruction and valve alignment and while in the process of open-ing a series of valves he inadvertently opened DH-V6A, Decay Heat Removal Pump suction from the Reactor Building Sump. The operator immediately realized his error and closed the motor operated valve before it reached full open. The total opening and closing time was approximately one minute. In the process, the Reactor Coolant System was partially drained from 150 inches to near 0 inches pressurizer level (about 4,000 gallons) . The Reactor Coolant System was still at about 15 psi following the occurrence.

CORRECTIVE ACTION The operator i= mediately realized his error and depressed the CLOSE push-button for DH-V6A. The plant was in a shutdown (startup and test) condition with no testing in progress. This occurrence required refilling, reventing and

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FoiSC, 7911070 707 y

, s Dr. D. R. Knuth, Director Directorate of Regulatory Operations United States Atomic Energy Commission Washington, D. C. 20545

,. repressurizing the Reactor Coolant System. No Technical Specifications were violated and no unresolved safety questions were involved. The approved operating procedure to accomplish the intended operation was being typed and was made available by October 29, 1973. In the future, when new operators are qualified and initially placed on the watchbill, the Shift Foreman will assure himself that the operator is appropriately briefed prior to performing plant operations. Approved operating procedures will also be used r.o accom-plish these operations during the integrated test program.

Very truly yours, ,

I

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,/d. G. Miller ice President brh cc:Mr. H. M. Dieckamp Mr. J. P. O'Reilly Mr. W. A. Verrochi -

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1584 327

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