ML19210D802
| ML19210D802 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 11/16/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Aswell D LOUISIANA POWER & LIGHT CO. |
| References | |
| NUDOCS 7911280094 | |
| Download: ML19210D802 (1) | |
Text
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION O%
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G11 RY AN PL AZ A DRIVE, SulTE 1000 E_
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November 16, 1979 In Reply Refer To:
RIV Docket No.
50-332/IE Information Notice No. 79-27 Louisiana Power and Light Co.
ATIN:
Mr. D. L. Aswell Vice President of Power Production 142 Delaronde Street New Orleans, Louisiana 70174 Gentlemen:
The enclosed IE Information Notice provides information ufch regard to the sequence of events that followed incidents involving steam generator tube ruptures at two PWR units.
Sincerely, I
l h
- b Karl V. S frit Director
Enclosures:
1.
IE Information Notice 79-27 2.
Recently Issued IE Information Notices
- C 345.>.
79uaaoo$
SSINS No.:
6870 Accession No.:
7910250483 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMEFT WASHINGTON D.C.
20555 IE Information Notice No. 79-27 Date: November 16, 1979 Page 1 of 7 STEAM GENERATOR TUBE RUPTURES AT TWO PWR PLANTS Description of Circumstances:
In recent montha two incidents involving steam generator tube ruptures have occurred.
In both instances, the units were cooled down and placed in the residual heat removal made with existing procedures.
Event of June 25, 1979 at the Doel 2 Nuclear Power Plant in Belgium The first event occurred on June 25, 1979, at the Doel 2 nuclear power plant in Belgium.
The Doel unit is a 390 Mwe Westinghouse two-loop reactor.
The event consisted of a rupture of several tubes in the loop B steam generator. The resultant leakage between the primary and secondary systems was estimated to be 125 gpm.
The event started when the plant was heated up after a shutdown caused by a malfunction of the main steam isolation valve. At the time of the incident the primary coolant pressure was:
2233 psi and the temperature: 491?F. The reactor remained subcritical throaghout the event.
The first indication of abnormal behavior was a rapid decrease of the primary system preasure (approximately:
28 psi / min.).
This was followed by the sequence of events listed oclow:
Time, min.
1.
Increase of charging flow demand, requiring startup of a second 1.8 charging pump.
2.
Automatic isolation of the CVCS letdown line.
2.4 3.
Shut off of the pressurizer heaters due to low liqaid level in the 2.4 pressurizer.
4.
Clcsing of black valver. in the pressurizer relief line.
4.6 5.
Rapid increase of water lev (
The sr,eam generator was iso 6.
Startup of the third chatgi DUPI.ICATE DOCUMENT 1435 5
all charging pumps from the tank.
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ANO No. of pages:
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