ML19211C067
| ML19211C067 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 11/16/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8001100038 | |
| Download: ML19211C067 (1) | |
Text
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NUCLEAR REGULATORY COMMISSION LPDR oq UNITED STATES PDR:HQ
@b tr REGION IV
% p,\\,,,1((/ s E I l o 611 RY AN PLAZA oRIVE,SUtTE 1000 o _pg.-l ili x / -j ARLINGTON, TEXAS 76012 NSIC m
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% ',2. ) 4 Nove=ber 16, 1979 Docket No.
50-298 Nebraska Public Power District ATTN:
J. M. Pilant, Director Licensing & Quality Assurance Post Of fice 3o:s 499 Colu= bus, Nebraska 68601 Gentle =en:
The enclosed IE Infor=ation Notice provides infor=ation with regard to the sequence of events that followed incidents involving steam generator tube ruptures at two PUR units.
Sincerely,
[
M 4-Karl V.
frit Director
Enclosures:
1.
IE Infor=ation Notice 79-27 2.
Recently Issued IE Infor=ation Notices cc:
L. C. Lessor, Superintendent Cooper Nuclear Station Post Office Bo:c 98 Brownville, Nebraska 68321 1739 064 2
800110 0 C) M
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 7 STEAM GENERATOR TUSE RU?IURES 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 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 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 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 pressuricer heaters due to low liquid level in the 2.4 pressurizer.
4.
Closing of block valves in the pressurizer relief line.
1739 065 4.6 5.
Rapid increase of water level ir l
The steam generator was isolate DUPLICATE DOCUMENT 6.
Startup of the third charging p all charging pu=ps from the CV Entire document previously tank.
entered into system under:
ANO 5
I No. of pages:
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