ML20084S664

AO 50-265/75-24:on 750720,crack Found on Reactor Feedwater Sys Flushing Line 2-3206B-4-C.Caused by Stress Point Due to Improper Blending of Fillet Weld.New Section of Pipe Welded

ML20084S664
Person / Time
Site:	Quad Cities
Issue date:	07/29/1975
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20084S667	List: ML20084S664 ML20084S679
References
AO-50-265-75-24, NJK-75-385, NUDOCS 8306170156
Download: ML20084S664 (2)

Text

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o o REPORT NUMBER: A0-50-265/75-24 .

REPORT DATE: July 30, 1975 OCCURRENCE DATE: July 20, 1975 IDENTIFICAT10tl 0F OCCURRENCE:

Crack on Reactor Feedwater System Flushing line 2-3206B-4"-C.

CONDITIONS PRIOR TO OCCURRENCE:

Unit 2 was in the Run Mode at 1460 HJt and 440 MWe .

DESCRIPTION OF OCCURRENCE:

On July 20, 1975, at 2:30AM, a search for leakage was commenced due to excessive operation of Reactor Building Floor Drain Sump Pump 2B. At 7:00PM the leak was located on line 2-32068-4"-C, the B reactor feedwater flushing line, at the point where it is welded to the main feed header. An orderly shutdown was commenced at 8:30PM and the reactor f

was shutdown at 4:40AM on July 21, 1975 DESIGNATION OF APPARENT CAUSE OF OCCURRENCE:

l Equipment Failure -

The apparent cause of this occurrence is designated as equipment failure. The crack originated at a stress point on the weld joining the pipe to a reinforcing plate at the junction of the flush line to the main header. The stress point was apparently caused due to improper blending of a fillet weld at the pipe to reinforcing plate joint.

ANALYSIS OF OCCURRENCE:

The failed sine was beyond the boundary of the primary coolant. isolation valves. Thus, the leak was capable of being isolated by action of the check-valves in the feedwater_ l line to the reactor. The supply of coolant to the reactor was not jeopardized since  !

the Emergency Core Cooling Systems were operable at the time of the occurrence. There I was no radioactivity released to the environs; thus, there was no effect on the health and safety of the public as a result of' this occurrence.

CORRECTIVE ACTION: .

'An 8 inch section of pipe which contained the crack was removed and a new section was welded in place.

i FAILURE DATA:

There have previously been several similar failures in the Feedwater System at Quad-Cities Station due to vibration problems. Proposed solutions to the vibration problem are cur-rently being designed by the Edison Station Nuclear Engineering Department.

8306170156 750729 t PDR ADOCK 05000265 l S PDR I

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/ Comm: Ilth Edixn .

/ d. Quad Cit encrating Station 4

! Post OfficcTox 216

\ / / Cordova,lihnois 61242

. _/ Telephone 309/654-2241 NJK-75-385 July 29, 1975 i

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Director of Office of Nuclear Reactor Regulation i l '. 'O U.S. Nuclear Regulatory Commission 'M' I' Washington, D.C. 20555 ~g

Reference:

Quad-Cities Nuclear Power Station Docket No. 50-265, DPR-30, Unit 2 Appendix A, Sections 1.0.A.5, 6.6.B.I.a Enclosed please find Abnormal Occurrence Report No. 50-265/75-24 for quad-Cities Nuclear Power Station. This occurrence was.previously reported to Region lil, Directorate of Regulatory Operations by telephone on July 21, 1975 and to you and Region ill, Directorate of Regulatory Operations by telecopy on July 21, 1975 This report is submitted to you in accordance with the requirements of Technical Specification 6.6.B.I.a.

s Very truly yours, COMMONWEALTH EDIS0tl COMPANY QUAD-CITIES NUCLEAR PO\lER STATION

/

jfl .c 'Hb dWl N.J. Kal ivianakis /

Station Superintendent

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cc: Region Ill, Directorate of Regulatory Operations J.S. Abel J', 'I Sb ;mj ap+4 l

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