ML20207H154

PNO-77-211:on 771123,aluminum Condensate Storage Tank Line Failed at Weld in Fabricated Y Junction Spilling Approx 100,000 Gallons of Water to Reactor Building Basement.Unit Remains Shutdown for Repair of Failed Line

ML20207H154
Person / Time
Site:	Browns Ferry
Issue date:	11/25/1977
From:	Nolan F, Whitt K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:
References
PNO-77-211, NUDOCS 9903120253
Download: ML20207H154 (2)

Text

WHimmun not niuu luN f D R ddV M Mw _

n. Novt ,er 25,1977k lp l 1'

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL

• gOCC l This preliminary notification constitutes EARLY notice of an event of i POSSIBLE safety or public interest significance. The information i presented is as initially received without verification or evaluation I and is basically all that is known by IE staff on this date.

' FACILITY : Tennessee Val' ley Authority I *

' Browns Ferry Unit No. 3

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SUBJECT:

CONDENSATE TANK EFFLUENT LINE FAILURE ,

On November 23, 1977, an aluminum 24-inch diameter condensate storage tank line failed at a weld in a fabricated "Y" junction spilling approxi-mately 100,000 gallons of water to the reactor building basement.

A water level of approximately one foot resulted in rooms housing the  !

torus residual' heat removal, core spray, and reactor core isolation 1

.! cooling systems. j

, - All safety-related systems remained operational. Spilled water was 1 essentially free of. radioactivity and was contained within the building.

5 Prior to the line failure, the reactor tripped from 95% power during 0 surveillance testing activities on the. main steamline high flow switches.

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With one channel in a tripped condition, a spurious signal was received - -

on a second channel This resulted in automatic shutdown.of the reactor

( 4 and closure of the main steam isolation valves. During the resultant y transient, High Pressure Coolant Injection (HPCI) flow and reactor core q isolation cooling (RCIC) automatically started on a low water level signal to refill the reactor vessel using condensate storage tank water. The licensee believes that the water surge during the HPCI start led to the pipe weld failure. The condensate storage tank prnvides the initial i source of water for coolant injection. When this source is not available coolant injection pump suction is autumatically switched i to the torus. Based on the safety analysi.s, the condensate storage

. tank is not required during accident conditions since the analys,is --

i ' assumes that the torus provides adequate water for safety injection. g The. source of coolant water for the HPCI automatically switched from the J condensate storage tank to the torus about the tine the HPCI shut down, '

i after refilling the-reactor vessel. y l' Unit remains shutdown for repair of the failed line and other unrelated IF maintenance activities. Reactor restart is expected late u. November 25,

, 1977.

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Media interest is not expected. . A news release is not planned by.the licensee or'the NRC. The State of Alabama has been informed.

{ ,, , n CONTINUED l . . . . C <.

1 9903120253 771125 PDR I&E PND-77-211 PDR

l PNO-77-211 Continued November 25, 1977 This Preliminary Notification is submitted for information only .

Unit Nos.1 and 2 were not ope' rat'ing during this event.

being refueled and Unit No. 2 low pressure turbine Unit No.1 is is being repaire phone discussion with Assistant Plant Superinte November 23.

- This information is current as of 9:30 a.m.ber on25.Novem.

Contact:

KWhitt. IE x28019 FJNolan, IE x8019 .

Distribution: Transmitted H St /* **'*"' ' .

3 Chainnan Hendrie Commissioner Kennedy Commissioner Bradford 3 S. J. Chilk, SECY.  :

Commissioner Gilinsky '

C. C. Kammerer, CA i

' (For Distribution)

1. Transmitted: MNBB/ arts P Bldg "'i L. V. Gossick, EDO ~ .

E. Volgenau

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S. H. Hanauer, EDO E. G. Case, NRR Region # , IE #*O  !

J. J. Fouchard, PA R. Hartfield, MIPC SS Bldg /> lf"jf (MAIL i

R. G. Ryan, OSP C. V. Smith, NMSS R~ LIT)McTiernan,OIA {

s H. K. Shapar, ELD R. Hinogue, SD

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PRELIMINARY NOTIFICATION ,_ ,

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