ML19210E546
| ML19210E546 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 11/16/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Andognini G BOSTON EDISON CO. |
| References | |
| NUDOCS 7912050225 | |
| Download: ML19210E546 (1) | |
Text
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h, UNITED STATES NUCLEAR REGULATORY COMMISSION y y 3.., (
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...., I 1 UTI Docket No. 50-293 Boston Edison Company M/C Nuclear ATTN:
Mr. G. Carl Andognini, Manager Nuclear Operations Department 800 Boylston Street Boston, Massachusetts 02199 Gentlemen:
The enclosed IE Information Notice No. 79-27 provides informat'on with regard to the sequence of events that followed incidents involving steam generator tube ruptures at two PWR units.
If you have any questions regarding this matter, please contact this office.
Sincerely, N/YL $l
. bkij-N yce H. Grier Bo f
&irector
Enclosures:
1.
IE Information Notice No. 79-27 2.
List of Recently Issued Information Notices CONTACT:
W. H. Baunack (215-337-5334) cc w/encls:
P. J. McGuire, Pilgrim Station Manager 1500 109 naoso DM
ENCLOSURE 1 SSINS No.:
6870 Accession No.:
7910250488 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON D.C.
20555 IE Information Notice No. 79-27 Date:
November 16, 1979 Page 1 of 9 STEAM GENERATOR TUBE Rt.'PTURES AT TWO PWR PLANTS Description of Circumstancec:
In recent months two incidents involving steam generator tube ruptures have occurred.
In both instances, the units were 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 Juna 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 th.oughout the event.
The first indication of abnormal behavice was a rapid decrease of the primary system pressure (approximately:
28 psi / min.).
Ti.is 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.
?.
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.
DUPLICATE DOCUMENT Entire document previously entered into system under:
^"o 7 ?/ o # A M 1500 110 No. of pages:
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