ML20084K531

AO 50-265/74-14:on 740619,nipple on Pressure Test Connection on Feedwater Header Cracked.Caused by Unsupported Cantilever Arrangement of Piping & Cyclical Vibrations.Nipples Repaired & Newly Designed Addl Bracing Installed

ML20084K531
Person / Time
Site:	Quad Cities
Issue date:	06/28/1974
From:	Kalivianakis N COMMONWEALTH EDISON CO.
To:	Oleary J US ATOMIC ENERGY COMMISSION (AEC)
Shared Package
ML20084K533	List: ML20084K531 ML20084K546 ML20084K554
References
AO-50-265-74-14, NJK-74-136, NUDOCS 8305190465
Download: ML20084K531 (3)

Text

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June 20,1974

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Mr. John F . O ' Leary, Di rector Directorate of Licensing Regulatiren U . S. Atomi c Energy Comi ssion t!ashington, D. C. 20545

Reference:

Quad-Cities t!uclear Power Station Docket No. 50-265, DPa-30 Appendix. A, Section 1. 0.A .4, 6.6.B . I .a

Dear Mr. O ' Leary:

Enclosed pleasa find Abnormal Occurrence Rr port t.o. A.O. 50-265/74-14 for Quad-Cities Muclear Fewr 5tetion. This occurrence was previour,1y reported to Region lil , Directcrate of Regulatory Operat ions by telephone and telecre:

co June 19, 1974, and to you by tcicgrca also on June 19, IS74 This report is subaitted to you in accordance wi th the requi rer c nts cf Tech-nical Specification Section 6.6.3.i.a.

Very t ruly yours, C0!;h0n'EALTil E]l SCN C0!'PA!;Y (BAD-C ITI ES NUCl. CAR PO'.lER STATI GL

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N. J. Kalivianakis S tation Superintendent NJK/CWS /j eh cc: Region t il , Di rec torate of I.cgulatory Operations J. S. Abel

Enclosure:

Abr.oroni O ccarrence P.cpor t No. 50-265/74-14

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V REPORT NUMBER: 50-265/74-14 REPORT DATE: June 28, 1974 OCCURRENCE DATE: June 19, 1974 FACILITY: Quad-Citics Nuclear Power Station Cordova, I llinois 61242 I DEllTIFICATION OF GCCURRENCE:

Cracked nipple on pressure test connection on feedwater header.

CONDITIONS PRIOR TO OCCURREllCE: Unit 2 in shutdown mode.

DESCRIPTICN OF OCCURRENCE:

At 10:00 A.M. on June 19, 1974, an inspection was made of the piping in the out-board MSIV room. Water was discovered leaking from pressure test connection 2-3211-3/4" where it taps into feedwater line 2-3204A-lE". Investigation revealed a cracked nipple where the test connection was welded to a weldolet on the feed-water line. Further investigation revealed a second cracked nipple on the 3/4" drain / equalizer line for RCIC testable check valve 2-1301-50.

OCC: C"f.T!C" Or A"Pf".CNT Cf."CC 0F CCC"RP.ENCE:

The subJcct nipple cracks were fatigue type failures assisted by inproper support.

Failure was caused by the unsupported cantilever arrangement of the piping. The problem was compounded by the cyclical vibrations of normal operation.

ANALYSIS OF GCCURRENCE:

The failed nipples were located on the portion of the feedwater header between feedwater check-valves 2-220-62A and 2 -220-59A . The -59A check valve is the out-board boundary of the prinary feedwater system. Complete failure or these nipples would have resulted in only a ninor reduction of feedwater availability to the reactor. Since a complete loss of the feedwater system is an cnalyzed design a cci den t , these failures did not threaten th" safety of the reactor and thus the safety implications are minimal. The health and safety of the public was not threatened because any contaminated uater resulting from the leaks would have been coatained in the floor drain system and processed through the radwaste facility.

Additionally, any air-borne contamination resulting f rom the leaks would have been handled by the reactor building ventilation system since the area is within the secondary containment boundary and thus is subject to the constraints of tnat system.

CORRECTIVE ACTION:

Assistance in analysis of the r. ode of failure was obtained f rom the Corporwealth Edison Cocpany Operational Analysis Department. Hinc cdditicaal small lines are b .!. .~

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REPORT liUMBER 50-2f'c/74-14

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PAGE 2 similarly attached to the feedwater system in the immediate area of the failures.

These lines were examined and found intact. The Cor.conwealth Edison Company.

Mechanical and Structural Engineering Departracnt, Sargent and Lundy Consulting Engineers, and Southwest Research Institute provided on-site assistance in desig-nating adequate bracing for proper support of these lines. The two cracked nipples-were repaired and leak tested. Recunmended additional bracing was installed prior to power operation of the unit.

FAllVRE DATA:

Previous similar nipple failures have not occurred at Quad-Cities Station in the safety-related section of the feedwater system. These failures are related to previously reported failures caused by vibration problems in this same area of the feedwater system. A study is being conducted at the station by Southwest Restarch Institute to try to resolve the vibration problems.