ML19210D798
| ML19210D798 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 11/16/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Weigand J GULF STATES UTILITIES CO. |
| References | |
| NUDOCS 7911280088 | |
| Download: ML19210D798 (1) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION o
" 'e REGloN IV l
611 HY AN PLAZA DRIVE, SUITE 1000 I _ f, ,i'i o
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7,q f. j ARLINGTON, TEXAS 7G012 srA a
% - ~.: y November 16, 1979 In Reply Refer To:
RIV Docket Nos.
50-458/IE Information Not# e No. 79-27 50-459/IE Information Notice No. 79-27 Gulf States Utilities Attn:
Dr. J. G. Weigand General Manager, Nuclear Projects Post office Box 2951 Beaumont, Texas 77704 Gentlemen:
The enclosed IE Information Notice provides information with regard to the sequence of events that followed incidents involving steam generator tube ruptures at two PWR units.
Sincerely, f
s Karl V.
frit Director
Enclosures:
1.
IE Information Notice 79-27 2.
Recently Issued IE Information Notices 1435
$33 nu28oo&8 4)
SSINS No.: 6870 Accession No.:
7910250488 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASilINGTON 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 months two incidents involving steam generator tube ruptures have occurred.
In both instances, the units tere cooled down and placed in the residual heat removal mode 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 nucicar power plant in Belgium. The Doel unit is a 390 Mwa 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 suberitical throughout the event.
The first indication of abnormal behavior was a rapid decrease of the primary system pressure (approximately:
28 psi / min.).
This was followed by the sequence of events listed below:
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 liquid level in the 2.4 pressurizer.
4.
Closing of block valves in the pressurizer relief line.
4.6 5.
Rapid increase of water level in tha damaad c ea-aoaae,* - /1 ~ - e o e.
The steam generator was isol-6.
Startup of the third chargin al harging pumps from the DUPLICATE DOCU N
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