ML20003C387

AO 50-219/74/25:on 740409,butterfly Valve V-26-16 Found Open & Primary Containment Integrity Lost W/Reactor Critical & Water Temp Greater than 212F.Cause of Component Failure Not Known.Valve Manually Forced to Seat Properly

ML20003C387
Person / Time
Site:	Oyster Creek
Issue date:	04/10/1974
From:	Ficheissen P JERSEY CENTRAL POWER & LIGHT CO.
To:
References
AO-50-219-74-25, NUDOCS 8103030267
Download: ML20003C387 (3)

Text

. Initici Teltphonc , Date of .

. Rep;rt Dito: '.i9/74 Occurrence: 4/9/74 Initial Written Time of ,

Repo.rt Dat'e: 4/10/74 Occurrence: 1040 )

1 I

OYSTER CREEK NUCLEAR GENERATING STATION FORKED RIVER, NEW JERSEY 08731 l l

Abnormal Occurrence Report No. 50-219/74/25 IDENTIFICATION OF OCCURRENCE: Violation of the Technical Specifications, paragraph 3.5. A.1, s loss of primary containment integrity with the reactor criti-

, cal and the reactor water temperature greater than 2120F.

This event is considered to be an abnormal occurrence as de-fined in the Technical Specifications, paragraph 1.15B.

CONDITIONS PRIOR TO OCCURRENCE: X Steady State Power Routine Shutdown llot Standby Operation Cold Shutdown Load Changes During Refueling Shutdown Routine Power Operation Routine Startup Other (Specify)

Operation The major plant parameters at the time of the event were as follows:

Power: Reactor,1849 MNt Electrical, 642 P.Me Flow: Recirc., 61 x 10 6 lbm/hr Feedwater, 6.9 x 106 lbm/hr Stack Gas: 34,895 pCi/sec DESCRIPTION OF OCCURRENCE: At 1040 on April 9, 1974, a local leak rate test on the reactor building to torus vacuum breakers was commenced and it was discovered that pressure could not be placed between V-26-15 and 16, the check and butterfly isolation valves. A check of leakage of drywell atmosphere to the reactor building l . was made. No leakage was indicated when a plastic bag was taped over the vent pipe. When pressure was again applied,

//) W . Y ,$ { h ..

Abnormal Occurrence Report No.. 50-219/74/25 Page 2 the bag filled with air indicating that the outside (check)

. valve was leaking. The check valve was cycled several times and then forced to seat. Air was again admitted between the valves and no leakage was detected through the check valve, 1, but the pressure would not exceed 17.5 psig. This indicated that the butterfly valve, V-26-16, was leaking. Upon inspec-t_ . ,

tion of V-26-16, it was found that the valve had not been in the fully closed position. The valve was fully closed manually and a successful leak test was performed.

The butterfly valve, V-26-16, was made inoperable, as permitted by Technical Specification 3.5. A.5. .

APPARENT CAUSE OF OCCURRENCE: Design Procedure Manufacture Unusual Service Condition Installation / Inc. Environmental Construction X Component Failure Operator Other (Specify)

The cause for valves V-26-15 and V-26-16 not to seal properly

- is not known at this time.

-ANALYSIS OF OCCURRENCE: An initial analysis of the data indicates that under accident conditions in the drywell (35 psig) the leakage rate through

.V-26-15 and V-26-16 would have been approximately 20** to 40%

of the allowable leakage rate from the primary containment.

Additional investigation is continuing.

, (

Abnormal Occurrence R; port No., 50-219/74/25 Page 3 CORRECTIVE ACTION: At 1408, a reactor shutdown was commenced. Both valves were

~

subsequently properly seated, successfully leak tested, and made inoperable. At 1443, the reactor shutdown was terminated and power was increased to the initial value.

AILURE DATA: History of torus to reactor building vacuum breakers:

11/23/70 - V-26-18 failed to open during operability surveillance 12/18/70 - V-26-16 and V-26-18 failed to open during operability surveillance 1/12/71 - V-26-18 failed leakage rate test 1/13/71 - V-26-18 linkage tightened one turn, passed leakage test but valve woul,d not open 1/14/71 - V-26-18 adjusted controller, passed leakage test and passed operability test 2/17/71 - V-26-16 and V-26-18 changed seats and both passed leakage tests 5/3/73 - V-26-18 failed leakage test. Linkage ad-justed and valve passed leakage and oper-ability tests.

Prepared by: g, e - Date: 4/10/74

. ,h-

.. .