ML19210D794
| ML19210D794 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 11/16/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Bryan J UNION ELECTRIC CO. |
| References | |
| NUDOCS 7911280080 | |
| Download: ML19210D794 (1) | |
Text
ff UNITED ST ATES o,
4 y
, e g,',g NUCLEAR REGULATORY COMMISSION REGION lit
'f'-
[
799 ROOSEVELT r.OAD r
N e [j
p, GLE N E LLYN, lLLINJis 60137 Docket No. 50-4',3 k
3 3I3 Docket No. 50-486 Union Electric Company ATTN:
Mr. John K. Bryan Vice President - Nuclear P. O. Box 149 St. Louis, MO 63166 Gentlemen:
The enclosed IE Information Notice No. 79-27 provides information with regard to the sequence of events that followed incidents involving steam generator tube ruptures at two PWR units.
Sincerely,
% 6)-
['
ames G. Keppler Director
Enclosures:
1.
IE Information Notice No. 79-27 2.
Recently Issued IE Information Notices cc w/encls:
Mr. W. H. Weber, Manager, Nuclear Construction Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Region I & IV Ms. K. Drey Mr. Ronald Fluegge, Utility Division, Missouri Public i435 527 Service Commission O
7911280
SSINS No.:
6870 Accession No.:
7910250488 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON D.C.
20555 November 16, 1979 IE Information Notice No. 79-27 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 were cooled down and placed in the rrsidual 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 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 plar.t 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 subtritical 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 3.
Shut off of the pressurizer hea DUPLICATE DOCUMENT pressurizer.
1435 W Ent;re document previously entered into system under:
ANO No. of pages:
!