ML20055J463

Package Consisting of Director Highlights of Unusual Event Due to Required Shutdown by Tech Spec 3.4.6.1 for Pressure Boundary Leakage.Unit Entered Cold Shutdown to Make Repairs. Estimated Restart Date Is 900522

ML20055J463
Person / Time
Site:	South Texas
Issue date:	05/09/1990
From:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:
Shared Package
ML20055J461	List: ML20055J460 ML20055J463
References
FOIA-90-258 NUDOCS 9008020296
Download: ML20055J463 (3)

Text

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INITIALS:

PD' d DIRECTOR HIGHLIGHTS PROJECT DIRECTORATE'- IV-l May 9, 1990 i 1

- South Texas Project. Unit 2 (STP-2)

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STP-2 declared an Unusual Event due to a required shutdown by. Technical Specifi- ,

cation 3.4.6.1 for Pressure Boundary Leakage (PBL). It has been determined <

that there is about a 10 al/ min. PBL on the 20 steam generator primary side ,

drain (channel head drain valve RC-0097). The leak is at a weld connecting a' ,

3/8" tube to the drain valve. The first indication of this. leak was a slight increase in contcinment gaseous activity over a week ago. A robot was sent into containment to ottemp_t to localize the leak. When it was determined that-the leak might be from a pressure boundary, a power. reduction was connenced.

At 0030 CST May 8, 1990, personnel confirmed that-it was PBL and the Unusual Event was declared. The unit has entered cold shutdown to make repairs.

Estimated restart date is May 22, 1990.

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CONTACT:

D. Pickett, NRR/PD-IV' 492-1344

/ I 90080go296900731 iV,'

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,, _ MMRAT_ IONS CfmITER,_

DIIEV4.t:ATED INFORIAAHUN PRO I' deb hhN FACILITY RES PUWIT NAIE PHONE W DOWN RESTART REASON OR COISENT *a_

T AltKABISAS 1 2271 000 RATED POE R 4 AltKAsISAS 2 2271 100 2272 000 05/09 05/10 IIODE 3 - HDT *#

4 COIWWICHE PEAlt 1 STAIIDSV RM TRIP DUE 10 LOSS OF FEED PUIIP COIITROL. SEE EVENT 19424.

ItICItEASIDIG POWER.

• 4 COOPER 2273 090 4 FORT CALHOUll 1 2274 000 02/17 05/21 nIODE 5 - COLD

'SHUTDoull REFUEttt8G OUTAGE 4 RIVER DEte 1 2276 100 4 l 4 SOUTH TEMAS 1 2277 000 03/29 05/28 IIODE 5 - COLD SeeUTDouN ..

4 SOUTH TEXAS 2 2277 000 .05/07 05/22 ts0DE 5 - COLD SHSTDOWIB PUTTIIIS '

- FREE 2E SEAL ABOUIS *

' ' AREA 0F PIIESSIIRE

' BOUISARY LEAIWiE.

4 WATERFa m 3 2278 '100 4 150Lf CIIEEE 1 2279 000 03/09 05/12 IIODE 3 - HDT STAIIDSV ROD DROP l .

TESTIBIE. _

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.PD 1 DIRECTOR HIGHLIGHTS ,

PROJECT DIRECTORATE - IV May 16, 1990 South Texas Project. Unit 2 The Director Highlight of May 9,1990 described a primary system leak on a 3/8"-

steam generator drain line. The leak was initially sensed by a containment radiation alarm on April 22 with Unit 2 operating at 1001 power. A robot sent behind tie biological shield wall. identified the steam leak and later, rith the power reduced to 141, personnel pinpointed the leak as being a cracked weld on the upstream side of the valve.

Root cause ' analyses by Bech'el concluded the broken weld to be vibration induced. Unit 2 has subsequently been reduced to Mode 5 for repairs.

Examinations by the licensee identified a similar crack on a second steam. >

generator drain line at Unit 2 and cracks in two of the four steam generator drain lines at Unit 1.

As a temporary fix, the licensee is installing l freeze- seals, removing the drain valves on all-steam generators at both units, capping the drain lines, and seal weldir g the caps. Permanent modifications are being investigated. Both units are currently in Mode 5 with Unit 1 continuing a refueling outage and Units 2 preparing to return to power this week.

CONTACT:

D. Pickett, NRR/PD-IV 492-1344

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