ML20085L842

Ro:On 710725,during Investigation of Scram Discharge Vol Draining Difficulties Following Planned Reactor Scram, Upper Isolation Valve for Scram Discharge Vol Level Switch 302-8A Found Closed.Caused by Personnel Error

ML20085L842
Person / Time
Site:	Dresden
Issue date:	08/03/1971
From:	Hoyt H COMMONWEALTH EDISON CO.
To:	Morris P US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20085L840	List: ML20085L842 ML20085L852
References
NUDOCS 8311030277
Download: ML20085L842 (2)

Text

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'O j Commonwealth Edison Company ONE F1RST N A T l o t4 A L PLAZA 4

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Dr. Peter A. Morris, Director Division of Reactor Licensing U. S. Atonic Energy Connission W shington, D. C.

20545

Subject:

LICTGE DIL25, DRESDi21 NUCLEAR FCEP. STATION tmIT #3 SECyION 6.6. A.1 AND 6.6.B.2 0F THE TECFNICAL SPECIPICATIONS Roference: Letter in Lieu of Tolegram Because of Western Union Strike to Mr. Boyec Grior from H. K. Hoyt, Dated July 26, 1971 Daar Dr. Morris:

This in to report a condition relating to the operation of the Station in which the upper isolation valve for a Seram Discharge Volume Lovel Switch was found in the closed pocition. The closed valve rendered the level switch inoperable, contrary to the requirements of Section 3.1 of the Drecden Unit 3 Technical Specifications.

Problem, Investigation, and Correctivo Action During investigation, at 0153 hours0.00177 days <br />0.0425 hours <br />2.529762e-4 weeks <br />5.82165e-5 months <br /> on July 25, 1971, of scram dischargo volume draining difficultion following a planned reactor scram at 2242 hours0.0259 days <br />0.623 hours <br />0.00371 weeks <br />8.53081e-4 months <br /> on July 24, 1971, the upper isolation valve for serara discharge voluna level switch 302 8A wao found in the closed position. The valva was opened inmediately. The closed isolation valveJendered the

-J.evol_owitch incapable of performing ito function at the set point specified in the Technical Specifications, although it would probably have operated at some higher discharge volue.3 level. The remaining three level switchen woro operable and perfor:ned ao required.

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.a Dr. Petcr A. Morris, Dir:ctor 2-August 3, 1971 Investigation renaled that the valvo had boen checked open during sycters valvo lineups ca June 11, 1971, and July 3,1971, and that a surysillance test of the subject lovel cwitch had been perfor: red en July 10, 1971. The procedure for this test requires closuro and subse-quent reopening of the isolathn valve. Review of the check list used indickted that, the valve wat reopened follo' ting the test.

A review of the records of entry to the scram dischargo volurn recm, and diccussion with personnel involved, revealed no work associated with the isolation v.11ve.

Thour,h the check list indicates the valve was reopened following the Lest, it is probable that it was not.

To minimize the possibility of recurrence, the 1:sportaneo of a censcientious check of valvire was reemphasized to the instru:nent maintenance r;roup. Additionally, the valvo check list has been revised to include tha ulve identificatica numbora to preclude error.

Sincarely,

.f H. K. Hoyt Suparintendent 1:Xi!:CJD:lz