ML19326B699

AO 50-313/74-12:on 741109,PDT-1035,PDT-1037 & PDT-1039 Reactor Protection Sys Instrument Line Socket Welds Failed. Cause Unknown.Tube on Each Side of Socket Weld Coupling Replaced W/New Coupling.Metallurgical Test in Progress

ML19326B699
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/05/1974
From:	Cavanaugh W, Phillips J, Reuter D ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19326B689	List: ML19326B688 ML19326B692 ML19326B695 ML19326B699 ML19326B704
References
NUDOCS 8004170538
Download: ML19326B699 (3)

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1. Abnormal Occurrence Report No. 50-313/74-12

3. ' Occurrence Date: 11/9/74

2. Report Date: 11/18/74 ,

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4. Facility: . Arkansas Nuclear One-Unit 1 '

Rus_sellville, Arkansas ,

PDT-1035, PDT-1037, and PT 1039

5. Identification of Occurrence:

Reactor Protection System (RPS) instrument line socket weld failure.

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- 6. -Conditions Prior to Occurrence:

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Reactor Power 0 MWth i Steady-State Power Net Output 0 MWe Hot. Standby 0

Cold Shutdown X Percent of Full Power  %

4 Refueling Shutdown Routine Startup Operation Routine Shutdown .

Operatio.n - -

Load Changes During Routine Power peration .

Other (Specify) 2 1'

7. Description of Occurrence: .

During a routine operator inspecfion at 1900 hours0.022 days <br />0.528 hours <br />0.00314 weeks <br />7.2295e-4 months <br /> on 11/9/74, boric acid crystals were noticed near the three socket welds between isolation valves RC-1039B, RC-1035B and RC-1036B, and instruments PT-1039, PT-103.5 and PDT-1037 respectively. 'these are RPS instrumentation lines (3/8" 0.

and 1/4" ID) on B RCS hot leg.

A 12S psig air test was conducted on the three socket weld couplings '

following removal and only one was found to be leaking through a pin-hole in'the weld. Further examination will be conducted to determine if all three welds were leaking or if boron crystals were deposited ort two welds from spray from the leaking weld.

I-8 004170j3I NSP-10, Rev. 0 - Page 1 of 3' July S, 1974

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Sheet 2 l- .

50-313/74-12 Abnormal Occurrence Report No.

8. - Designation of Apparent Cause of Occurrence _:

Procedure .

Design

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Unusual Service

-Manufacture Condition Including-Environmental Installation / _

f Construction- Component Failure Opere. tor Other (Specify) Not determined at this time.

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9. Analysis of Occurrence _:

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( l h and At the'Ihere time of no were the safetyoccurrence implications the or hazard reactor to thewas hea tat co fication tion.

safety of plant personnel or the public due to prompt identi and corrective action.

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10. Corrective Action: i ~;

A section of the tube 6" on either side of the socket weld c were removed and replaced with a new coupling.

at 2285 psig did not reveal any defects. .

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Page 2 of.3l NSP-ID, Rev. O July 5, 1974

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Abnormal Occurrence Report No. ' Sheet 3

'50-313/74-12

11. Failure Data: i

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i No prior failures of this type. Couplings are being given a metal -

'lurgical examination. These results will be submitted in a follow-up report. .

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12. Reviews and Approvals:

Reviewed and Approved by: Plant Safety Committee Yes (x) No ( )

Plant Superintendent Yes (X) No ( )

Reference:

JWA-667 Date: 11/18/74 Reviewed by: &- , Date: # 77[

~l ', Licensing Supervisor i

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Approved by: I , / //A pw., ,/ Date: // Y 6' M

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' / afet R'eview mmi ee Approved by: A [ , e s d i m M ;-'- Date: h 7

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' 'unager of ucearServic[

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n Approved byr  ;//* / & ~j t' p ['

Date: /[- / / '/

.[ Director of Power P oduction Approved by: / . /  ! /o Date: /' /f' Senior'Vice President ~

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NSP-10, Rev. O Page 3 of 3 July 5, 1974