ML20084L739

Suppl to AO 50-237/1974-31:mod of Valves 2-1601-31 a & B to Minimize Binding in Valve Disc to Disc Arm Joint Found Unnecessary & Will Be Canceled.Continued Surveillance Tests Show No Recurrence of Improper Valve Seating

ML20084L739
Person / Time
Site:	Dresden
Issue date:	09/22/1974
From:	Stephenson B COMMONWEALTH EDISON CO.
To:	James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20084L740	List: ML20084L739 ML20084L741 ML20084L744 ML20084L755
References
626-75, AO-740922, NUDOCS 8305230671
Download: ML20084L739 (1)

Text

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Common AOne First Nat th Edison

. Plaza. Chicago, ininois

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t  ! Q ' Addr:,ss Reply to: Post Office Box 767 Chicago, Illinois 60690 l

BBS Ltr. #626-75 Dresden Nuclear' Power Station R. R. #1 I Morris, Illinois 60450 September 22, 1975 gg- - s/s s

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Mr. James 0. Keppler, Regional Director _

( " ,, p-Directorate of Regulatory Operations-Region III 17 .:,

U. S. Nuclear Regulatory Cc:::nission 0d,-

799 Roosevelt Road Glen Ellyn, Illinois 60137 , ,

SUBJECT:

SUPPIR&'iT TO REPORT OF AENOR"AL OCCURPR!CE PER SECTION 6.6.A 0F THE ME;ICAL SPECIFICATIC:!S EXCESSIVE LElJ.AG3 FAST REACTOR BUILDING TO TORUS VACUUM EREAKER 2-1601-31A Report Number 50-237/1974-31 ,

In a letter to Mr. J. F. O' Leary, dated August 2,1974, concerning the subject occurrence, the corrective action described was to modify the valve to minimize binding in the valve disc to disc arm joint.

After further examination, evaluation and surveillance testing, it has been '

determined that the modification is unnecessary. The reactor building to-torus vacuum breaker valves are not identical to the torus to dryuell vacuum breakers and no significant corrosion was detected when the valve was disassembled and examined. On the basis of this c'xamination and other modifications to increase the closing force, the modification of the disc to disc arm connection has been reevaluated. Continued surveillance testing of these particular valves has shown no recurrence of improper seating of the valve. For the above reasons the modification to the disc to disc arm joint on valves 2-1601-31A & B is not necessary and will be canceled %. g ,

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'B. B. Stephenson Superintendent BBS:JSA:smp File /hRC h

e e . * , ? C egme 8305230671 740922

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