ML19343C342

AO 73-05:reactor Containment Automatically Operated Isolation Trip Valve Leaked Internally.Caused by Crack Between Seat & Body.Valve to Be Repaired or Replaced.Liquid Samples to Be Collected from Alternate Point in Interim

ML19343C342
Person / Time
Site:	Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png
Issue date:	06/22/1973
From:	Hartley F CONNECTICUT YANKEE ATOMIC POWER CO.
To:	US ATOMIC ENERGY COMMISSION (AEC)
References
AO-73-05, AO-73-5, CYH-2407, NUDOCS 8103100421
Download: ML19343C342 (3)

Text

.

Ngulatory 77e Cya CONNECTICUT YANKEE AT O M IC POWER COMPANY

)I HADDAM NECK PLANT I

RR c 1, BOX 127E. EAST H AMPTON, CONN. o6424 L

June 22,1973 CYH-2407 N

O W'

U. S. Atomic Energy Commission N E.[L)

Washington, D. C. 20545 ATTEtiTI0li:

Director, Directorate of Licensing

'J'JN 281973> 9 REFEREliCE: Provisional License tio. DPR-14 u fu mm Docket No. 50-213

//

g' Ed U 8 Abnormal Occurrence 73-5 q,

()

Dear Sir:

As defined by Technical Spec'fications for Connecticut Yankee Atomic Power Station, Section 5. i, the following incident involving malfunction of a reactor containment isolation valve is reported as Abnomal Occurrence 73-5.

Pipes penetrating the reactor containment are provided with valving to prevent uncontrolled discharge of fission products from the reactor containment to the atmosphere during accident conditions.

The pressurizer liquid phase sample line piping is provided with a manually operated isolation valve at the pressurizer, (inside the reactor containment) an automatically operated isolation - trip valve, (outside the reactor containment) and a second manually operated isol-ation valve (outside the reactor containment). The relative locathns of the valves in this line are shown on Figure I.

During the recen maintenance shutdown, the automatically operated isolation - trip gm j X g' valve was disassembled to inspect the valve internals to determine the reason for internal valve leakage. The inspection revealed a v

y cg?P g crack between the seat and the body, approximately 270 around the y

circumference of the seat. The trip valve has been isolated by closing the upstream and downstream manual isolation valves. The

,i281973 > S valve will be repaired or replaced during the forth coming refueling arms

,f fs shutdown.

In the interim period pressurizer liquid samples will be gyy p} collected from an alternate sample point.

'9

-W '

In assessing the safety significance of the malfunction of y

this valve one must evaluate the events that must simultaneously occur to provide a leakage path to the atmosphere. At the same time the trip valve was leaking through internally, a loss of coolant incident must occur, the liquid sample line must rupture and at least three manually operated isolation valves must be open to cause an uncontrolled discharge of fission products from the b

$DY kf

>- U. S. Atomic Energy Commissicn June 22,1973 -

reactor containment.

It is apparent that this is a rather incredible series of events, therefore we conclude that the safety of the public -

was not compromised with the malfunction'of the pressurizer liquid sample line trip valve.

The Plant Operations Review Committee reviewed the incident and recommended replacement or repair of the valve during the next major outage.

Very truly yours,

. W.

artley If Plant Superintendent RHG/bn cc: Mr. James P. O'Reilly, Director Region 1, Directorate of Regulatory Operations s

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