ML19326B325

AO 50-313/74-05:on 740708,valve Leaks Found in Clean Liquid Radwaste & Makeup Sys.Caused by Casting Flaws.Valve Defect Being Investigated

ML19326B325
Person / Time
Site:	Arkansas Nuclear
Issue date:	07/19/1974
From:	Cavanaugh W, Phillips J, Reuter D ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19326B323	List: ML19326B322 ML19326B325
References
NUDOCS 8004150708
Download: ML19326B325 (3)

Text

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1. Abnormal Occurrence Report No. 50-313/74-5

2. Report Date: July 19,1974 3.. Occurrence Date: July 8, 1974 4 Facility: Arkansas' Nuclear One-Unit 1 [~

, l S. Identification of Occurrence: Valve leaks in the clean liquid radioactive h waste and makeup systems. l l

6. Conditions Prior to Occurrence:

. i Steady-State Power Reactor Power 0 bMth

!!ot Standby Net Output 0 hMe ,

Cold Shutdown X Percent of Full Power 0 % i L

Refueling Shutdown l Routine Startup i Operation I Routine-Shutdown Operation [

Load Changes During Routine Power Operation ',L t

Other (Specify) Prior to Initial Criticality s

7. Description of Occurrence: ,4 A leak at MU-30A, located at the inlet to the seal return comer, was discovered by observing boron crystals forming on the valve. Further investigation resulted in the location of leaks at the following clean waste system 3" valves: [

CZ-8, inlet to vacuum degasifier . ~

CZ-17A, inlet to clean waste receiver tank B CZ-29, upstream from radwaste deminerali:er (for sluicing water)

C'-36A, downstream from C7.-29, inlet to spent resin storage tank

CZ-47A, inlet to treated waste monitor tank A [

! An investigation was initiated to determine the extent of the valve leaks. ',

503 80041 I

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Abnormal Occurrence Report No. 50-313/74-5 Sheet 2 j 8. Designation of Apparent Cause of Occurrence:

, Design Procedure i

Shnufacture X Unusual Service ,

Condition Including

, Installt. tion / Environmental Construction Component Failure Operator ,

l Other (Specify) l Initial investigation showed that all of the cican waste valves werc ~I cast using heat number 7978. MU-30A has the heat number 7984 Since all of the leaks occurred at approximately the same section of the l valve, the leak problem appears to be the result of casting flaws and  :

could be generic in nature.  !

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9. Analysis of Occurrence:

At the time of occurrence, the reactor building integrity was not  !

O required since initial criticality had not been reached. No safety implications were involved and the health and safety of the public was not effected. - l'

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10. Corrective Action: l The extent and cause of defect in the valves are being investigated. ,

, The valves will be repaired or replaced as required.  :

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' July 5, 1974 NSP-10, Rev. O Page 2 of 3 ,,

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Abnormal Occurrence Report No. 50-313/74-5 Sheet 3

11. Failure Data:

There have been no previous failures of this type. All valves can be identified by the Bechtel mark number, R\RK 29M2-III. Nameplate data 1

is as follows:

3" 1508 B. B. Cate Valves S/S Valve Class N3 D@Q D bw~'

D 9 }

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V - :_ b a

12. Reviews and Approvals:

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

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Plant Superintendent Yes (.9 No ( )

Reference:

JWA-411 Date: 7/18/74 fY( . twt l ),'. *,'%un.4 Reviewed by: t ;hu h N . .I' .</N Date: 7 / ' '/ y'

, Licensing Supervisor '

• Approved by:( //// w llI-f .

., c I M Datc: 7- > > - Y

. ' Saf ty Rev

• ew C.ommittc [ II

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Approvedby&f,_

thn .t ! Ni,W inager ori ucicar Date: 7 /9 77 ices /

Approved by:[d//// // ,,[- , .. .,[ Date: _ 'A. *> - M

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/ m Director of j m Power Production

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Approved by: k n Date: - e '- 4 t Senior Vice President ' '

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