ML19253C368

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Forwards IE Info Notice 79-27, Steam Generator Tube Ruptures at Two PWR Plants. No Response Required
ML19253C368
Person / Time
Site: 05000516, 05000517, Shoreham  File:Long Island Lighting Company icon.png
Issue date: 11/16/1979
From: Grier B
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To: Wofford A
LONG ISLAND LIGHTING CO.
References
NUDOCS 7912050256
Download: ML19253C368 (1)


Text

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(KING OF PRUSSI A, PENNSYLV ANIA 19406 Docket Nos. 50-322 N0'/16 m) 50-516 50-517 Long Island Lighting Company ATTN:

Mr. Andrew W. Wofford Vice President 175 East Old Country Road Hicksville, New York 11801 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.

If you have any questions regarding this matter, please contact this office.

Sincerely, f

r 9'i/% N/I [f $ W

/

Boyce H. Grier

,f!Tirector

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:

J. P. Novarro, Project Manager Edward M. Barrett, Esquire Edward J. Walsh, Esquire T. F. Gerecke, Manager, Engineering QA Department 1503 033 7 0120 a m

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 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 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 r' ant 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 throughout the event.

The first indication of abnormal behavior was a rapid decrease of the primary system pressure (approximately:

28 ps;/ 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 ct;arging 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.

DUPLICATE DOCUMENT Entire document previously entered into system under:

hO ANO No. of pages:

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