ML20055J463
| 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: |
| References | |
| FOIA-90-258 NUDOCS 9008020296 | |
| Download: ML20055J463 (3) | |
Text
r-1 INITIALS:
PD' d DIRECTOR HIGHLIGHTS PROJECT DIRECTORATE'- IV-l May 9, 1990 i
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- 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
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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 4 COIWWICHE PEAlt 1 2272 000 05/09 05/10 IIODE 3 - HDT STAIIDSV RM TRIP DUE 10 LOSS OF FEED PUIIP COIITROL. SEE EVENT 19424.
4 COOPER 2273 090 ItICItEASIDIG POWER.
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 l
STAIIDSV ROD DROP 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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