ML20084U274

AO 50-254/75-5:on 750223,small Leak Discovered on Reactor Feed Pump Discharge Line Ic.Caused by Failure of Weld Due to Improper Installation.Crack Repaired & Weld Corrected

ML20084U274
Person / Time
Site:	Quad Cities
Issue date:	03/05/1975
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J Office of Nuclear Reactor Regulation
References
AO-50-254-75-5, NJK-75-111, NUDOCS 8306280419
Download: ML20084U274 (3)

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Ouad-Cit:es Generet.ng Station f (E C (j l'ost Office Box 216 Cordova,I!!inois 61242

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Mr. John F. O' Leary, Di rector ';.If-Directorate of Licensing Regulation { ).3 " e s ,

U. S. Nuclear Regulatory Commission Washington, D. C. 20545 \']'J;3

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REFERENCE:

Quad-Cities Nuclear Power Station Docket No. 50-254, DPR-29 Appendix A, Sections 1.0.A.5 and 6.6.B.I.A.

Dear Mr. O' Leary:

Enclosed please find Abnormal Occurrence Report No. 50-254/75-5 for Quad-Cities Nuclear Power Station. This occurrence was previously reported to Region lil, Directorate of Regulatory Operations by telephone on February 24, 1975 and to you and Region lil, Directorate of Regulatory Operations by telecopy on February 24, 1975 Th!: .: crt !: rub--!tted te /cu ! 0 :crder.: -

. : !!F the requ!remer.t: Of Technical Specification 6.6.B.I.a.

Very truly yours, COMMONWEALTH EDISON COMPANY QUAD-CITIES NUCLEAR POWER STATION i / s' f,. i.-Y'-W WY N. J. Kal tvianakis +

Station Superintendent NJK/LDR/vmm cc: Region lil, Directorate of Regulatory Operations J. S. Abel 8306280419 750305 PDR ADOCK 05000254 S PDR 2553 O

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V REPORT NUMBER: A0-50-254/75-5 REPORT DATE: March 5, 1975 OCCURRENCE DATE: February 23, 1975 FACILITY: Quad-Cities Nuclear Generating Station Cordova, Illinois 61242 IDENTIFICAT'l0N OF OCCURRENCE:

Leak on IC Reactor Feed Pump Discharge Header CONDITIONS PRIOR TO OCCURRENCE:

Unit one in the run mode operating at 435 MWe and increasing at 3 MWe/hr for fuel pre-conditioning following an outage for replacement of the 4" Recirc By-Pass Loops.

DESCRIPTION OF OCCURRENCE:

At 10:56 P.M. on February 23, 1975, a small leak was discovered on the IC reactor feed pump discharge line. The Icak resulted from a crack in the weld joining a 3/4 inch radioactive sodium tracer tap to the 18 inch discharge header. This tap had been installed during the 1974 refueling outage to facilitate calibration of the feed pump flow elements. The reactor was shut-down at 5:25 A.M. on February 24th for repairs.

DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

Equipment (Piping) Failure Cause of the leak was determined to be a failure of the weld due to improper installation. When installed only one weld bead was used, whereas common practice is to lay three beads to complete the weld. Normal vibration of the feed pump discharge header then caused a small crack to develop in the weld.

ANALYSIS OF OCCURRENCE:

Safety implications are minimal. The small leak did not infringe upon the ability of the feedwater system to supply coolant to the reactor, or render the feedwater system inoperable. This also would have been true even if the 3/4 inch line v.ould have failed completely. All coolant leakage was contained in the reactor feed pump area of the turbine building; thus, no abnormal radi-ation exposures were experienced by plant personnel and there was no effect on the health and safety of the public.

CORRECTIVE ACTION:

Corrective actions consisted of shutdown of Unit one by 5:25 A.M. on February 24,

1975 The crack was then repaired and the weld properly completed. Seve ral i

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o additional welds installed with this same modification will be inspected in the near future and any required repairs will be made.

FAILURE DATA:

Various pin hole leaks and cracks at welds on piping have occurred at Quad-Cities Station in the past due to vibration. However, none in the past have been due to. improper installation such as in this case, where the weld was initially Installed but not properly completed.

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