ML20236L035

PNO-77-004:on 770105,plant Automatically Scrammed,Steam Flow Feed Flow Mismatch,From 54 Percent Power When Feedwater Line Vibration Experienced.Licensee Determining Extent of Damage Which Occurred

ML20236L035
Person / Time
Site:	Beaver Valley
Issue date:	01/06/1977
From:	Dreher F, Roy G, Thompson D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-004, PNO-77-4, NUDOCS 9807100187
Download: ML20236L035 (2)

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<- PRELIMINARY NOTIFICATION

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January 6, 1977 -

I PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE-PNO-77-04 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 and is basically all that is known by IE staff on this date. *

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Facility: Beaver Valley Unit No. 1 .

(DN 50-334)

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Subject:

FEEDWATER SYSTEM PIPING VIBRATION (THIRD OCCURRENCE) i The plant automatically scrammed, steam flov feed flow mismatch, from 54 percent power at 7:00 p.m., January 5, 1977 when feedwater line vibration i was experienced. Similar vibrations had occurred on November 5 and December 27, 1976 (Reference PN0s76-186 and 76-225). The'11censee is determining the extent of damage which occurred. Damage found so far i

is: (1) the motor operator for the B feedwater line containment isolation i l valve broke off of the valve, (2) three air lines to the B feedwater "!  !

bypass regulating valve pulled out of their fittings, (3) a pressure I impulse line to the B feedwater pressure transmitter pulled out of its A fitting and (4) insulation damage on the B&C feedwater line occurred.

A containment entry to determine any damage inside containment has not

[ yet been made. s 1

1 Steady state operation at 75 percent power had been authorized by NRC (

, pending planned modifications to attempt to resolve this vibration problem. The plant power was reduced from 75 percent to 54 percent power when a heater drain pump and a feedwater pump tripped. The pumps were restored to operation and the operators were preparing to increase power when the vibration occurred. The vibration lasted for about 15 seconds. '

The licensee is using consultants to assist in their analysis of the occurrences and the damage which occurred.

Media interest is expected because of previous similar occurrences and close attention given at nuclear plants. The Commonwealth of Pennsylvania ,

has been informed. A press release is being consider'ed by the licensee. >

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.i CONTINUE

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9807100187 770106 PDR I&E PNO-77-004 PDR _

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Page'2 PNO-77-04 Continued -

January 6, 1976 NRC, Region I, (Philadelphia) received notification of this occurrence by I

telephone from the Plant Superintendent at 9:15 p.m., January 5, 1977.

The information is current as of 8:15 a.m., January 6,1977.

Montact: FADreher, IE x27261 GWRoy, IE x27261 DThompson, IE x27541 >

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-Distribution: '

Chairman Rowden Commissioner Mason S. J. Chilk, SECY Commissioner Gilinsky C. C. Kammerer, CA G. F. Murphy, JCAE i Commissioner Kennedy I

! L. V. Gossick, EDO K. R. Chapman, NMSS R. G. Ryan, OSP S. H. Hanauer, EDO E. Volgenau, OIE J. A. Harris, PA B. C. Rusche, NRR H. K. Shapar, ELD T. J. McTiernan, OIA '

amme j Transmitted: PBldg0// 3 ; H St// d ; MNBBl[N ; Luga M ;

PRELIMINARY NOTIFICATION i

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