ML19326B400

AO 50-313/74-08A:on 741003,initial Investigation Per AO 50-313/74-08 Revealed Thta Loss of Core Flood Tank Ref Leg Resulted from Evaporation.Investigation Found Evidence of Leakage on Ref Legs of Each Tank

ML19326B400
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/16/1975
From:	ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19326B395	List: ML19326B394 ML19326B400 ML19326B403
References
NUDOCS 8004150766
Download: ML19326B400 (3)

Text

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1. Abnormal Occurrence Report No. 50-313/74-8A 4

2. Report Date: July 16,'1975 3. Occurrence Date: October 3, 1974

4 Facility

Arkansas Nuclear One-Unit 1 i Russellville, Arkansas

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5. Identification of Occurrence

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i See Abnormal Occurrence Report No. 50-313/74-8 dated 10/9/74.

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6. Conditions Prior to Occurrence:

Steady-State Power Reactor Power SIWth I

!!ot Standby Not Output SINC Cold Shutdown Percent of Full Power "6 Refueling Shutdown Load Changes .During Routine

. Power Operation l Routine Startup -

4 Operation

Routrie Shutdown Operation j- Other (specify) '

l See Abnormal Occurrence Report No. 50-313/74-8 dated 10/9/74.

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7. Description of Occurrence: ~:

See Abnormal Occurrence Report No. 50-313/74-8.

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l 800415074g t! arch 4, 1975 NSP-10, Rev. 2 Page 2 of 4

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Abnormal Occurrence Report No. 50-313/74-8A

8. Designation of Apparent Cause of Occurrence:

Design X Frocedure Ahnufacture . Unusual Service Condition ~

including Environmental Installation /

Crestruction Componen: Fellure Cy rstor Other (specify) _

Initial investigation as reported in AOR 50-313/74-8 revealed that loss i of the core flood tank reference leg was a result of evaporation as no j leakage was found. Investigation per corrective action of AOR 50-313/74-8 revealed evidence of leakage on the reference legs of each tank.

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9. Analysis of Occurrenec:

See AOR 50-313/74-8.

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j .^ bnormal' Occurrence Report No. 50-313/ 74-8A

10. Corrective .?.ction:

Remaking and, in some cases, replacement of fittings were directed 'a y plant personnel with pressure tests follcwing the work. A new surveil-lance program was established on 11/12/74, and readings were taken periodically for two months to discover any trends indicating level changes in reference legs. Console readings and transmitter voltage outputs were read each time showing a deviation over the period of not more than 0.19 feet and 0.28 feet, respectively.

Drift has been concluded to have been caused by leakage at the fittings.

This situation has been corrected and better resolution scales have been installed. Procedures will remain in effect that, before the core flood ,, .

tanks are drained, the Instrument and Controls Supervisor will be con-suited concerning the need to check the reference legs.

11. Failurc Data: .

7- s., , See AOR 50-313/74-8.

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