ML20236F265

PNO-76-186:on 761105,rumbling Was Heard in Operating Areas & Guard House.Drain Line 3/4 Inch on AFW Line to B SG Had Failed.Licensee Plans to Have Westinghouse & Stone & Webster Analyze Event to Determine Cause

ML20236F265
Person / Time
Site:	Beaver Valley
Issue date:	11/08/1976
From:	Dreher F, Roy G, Thompson D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-76-186, NUDOCS 9807020093
Download: ML20236F265 (2)

Text

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, h PRELIMINARY NOTIFICATION w.

November 8, 1976 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE-PNO-76-186 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation l and is basically all that is known by IE staff on this date. I Facility: Beaver Valley-1 (DN 50-334)

Subject:

FEEDWATER DRAIN LINE FAILURE AND LINE MOVEMENT

• At 10:00 p.m., November 5, 1976 a " rumbling" was heard in the operating areas and guard house. Immediate investigation by the licensee showed that a 3/4 inch drain line on the Auxiliary Feed Water (FW) line to the B, Steam Generator had failed (a 360 degree circumferential failure). The ,

failure location was in the room (outside the Containment Vessel) which contains the main FW containment isolation valves and main steam isolation valves.

The reactor has been put in the cold shutdown condition.

Subsequent investigation has revealed a broken hydraulic shock suppressor I on the 16 inch B FW line inside containment, a small bend (a few degrees) in l the B FW line at the containment liner attachment plate, small movement (in the order of 1/2 inch) of the safety class portions of Main and Auxiliary B_ W lines outside containment, movement (in the order of 6 inches) of the A, Main FW control valve bypass line, air lines broken from the bypass FW control g valve in the A Steam Generator line, and the motor operator broken off of g the B, auxiliary FW containment isolation valve. Inspection inside contain-mer.c is not yet complete and is continuing.

At this time it is not clear whether the 3/4 inch drain line failure was (2 the initiating event or a result of the occurrence. The licensee plans to 2 have Westinghouse and Stone and Webster analyze the event to determine the cause. In addition the contractors will assist in determining nondestructive examinations (NDE) of piping and welds which will be performed to assess damage. One contractor will perform stress analyses on the piping systems involved.

Present plans are to perform NDE on all welds inside containment and on the safety class portions of the Main FW and Auxiliary FW lines outside containment.

CONTINUE

.Q 9807020093 761108 PDR I&E PNO-76-186 PDR

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Continued PNO-76-186 Page 2 November 8, 1976 NRC: Region I dispatched two inspectors to the site on Sunday, November 7, 1976, one to analyze operating events which lead to and resulted from the occurrence and one to assess the NDE and stress analyses to be performed and to observe physical conditions.

g The NRR Project Manager was briefed on the occurrence on November 6, 7, and 8, 1976.

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Media interest is expected because of close attention given to problems- I at nuclear power plants. The Commonwealth of Pennsylvania has been informed. A press release was made by the licensee on November 6, 1976.  !

Region I, NRC, Philadelphia, Pennsylvania received initial notification i

of this_ occurrence _by_ telephone _from_the. Plant Superintendent _at_ noon, _.. _

i November 6, 1976. Subsequent communications with .the . Plant _ Superintendent, i Stone and Webster and the NRC:I Inspectors occurred on November 6, 7, and 8, 1976.

This information is current as of 2:30 p.m., November 8, 1976. I

Contact:

FADreher, IE x27261 GWRoy, IE x27261 DThompson, IE x27541 Distribution:

. Chairman Rowden Commissioner Mason S. J. Chilk, SECY  :

Commissioner Gilinsky C. C. Kammerer, CA G. F. Murphy, JCAE Commissioner Kennedy L. V. Gossick, EDO ' E. Volgenau, OIE J. A. Harris, PA B. C. Rusche, NRR H. K. Shapar, ELD T. J. McTiernan, AIA K. R. Chapman, NMSS R. G. Ryan, OSP ,

Transmitted: PBldg  ; H St  ; MNBB  ; Luge  ;

PRELIMINARY NOTIFICATION

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