ML19345G174
| ML19345G174 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 01/18/1974 |
| From: | Hartley F CONNECTICUT YANKEE ATOMIC POWER CO. |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| AO-74-02, AO-74-2, CYH-2570, NUDOCS 8103100188 | |
| Download: ML19345G174 (1) | |
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CONNECTICUT YANKEE ATO MIC POWER COMPANY
~ C3, HADDAM NECK PLANT
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RR = 1. BOX 127E, EAST H AMPTON. CONN. 06424
'.b January 18, 1974 CYH-2570 Mr. James P. O'Reilly, Director qf 50-213
. j, 7 Region 1 g/, U E
Directorate of Regulatory Operations f+%
7' U. S. Atomic Energy Commission 631 Park Avenue King of Prussia, Pennsylvania 19406
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Dear Mr. O'Reilly,
As defined by Technical Specifications for Connecticut Yankee Atomic Power Station Section 5.3, the following information involving the malfunction of two main steam line excessive flow differential pressure transmitters is reported as Abnomal Occurrence 74-2.
At 0612 this date a data logger alarm message was received indicating a main steam line high steam flow condition in the #2 steam line. Two minutes later a similar high steam flow condition was annunciated for the #1 steam line. The coincidence of two high steam flow signals satisfied the trippina logic and a reactor / turbine trip occurred from fullpower(s600MWe).
S.bsequent investigation revealed frozen instrument sensing lines leading to the differential pressure transmitters for the #1 and #2 main steam line excessive flow instrus. The instrument sensing lines were thawed and the instrumentation returned to normal.
The instruments in question are housed in an er. closure attached to the outside of the reactor containment.
Sub-zero temperatures and strong winds created the freezing environment. Additionally two unit heate.
in the affected area were not operating.
Tiie two unit heaters were repaired and returned to service. Other freeze protection measures are currently under investigation.
Very truly yours, 3
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"U F. W. Hartley Jpy' U U4 Plant Superint ndent M
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I cc:
Mr. A. Giambusso g
Deputy Director for Reactor Projects
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Directorate of Licensing II O
l U. S. Atomic Energy Comission Office of Regulation 6M Washington, D. C. 20545 nnnn n n I n 111 A I -
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