ML19326B665

AO 50-313/74-10:on 741025,leak from Cold Leg Loop Weld of RCS Was Discovered & Determined to Be Same Weld Reported in AO 50-313/74-09.Cause Unknown.Weld Removed & Sent to B&W Lab for Analysis

ML19326B665
Person / Time
Site:	Arkansas Nuclear
Issue date:	11/04/1974
From:	Cavanaugh W, Kueter D, Phillips J ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19326B655	List: ML19326B654 ML19326B659 ML19326B663 ML19326B665 ML19326B675
References
NUDOCS 8004170512
Download: ML19326B665 (4)

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1. Abnormal Occurrence ' Report No. 50-313/74-10

2. gnortDate: November 1, 1974- 3. Occurrence Date: October 25, 1974

4. Facility: Arkansas Nuclear One-Unit 1 Russellville, Arkansas

. 5. Identification of Occurrence:

See page la. .

6. Conditions Prior to Occurrence:

Steady-State Power X Reactor Power ~

1922 MWth Hot Standby Net. Output 637 MWe Cold Shutdown Percent of Full Power 75 %

Refueling Shutdown Routine Startup Operation Routine Shutdown '

Operation ,

Load Changes During Routine Power Operation '

Other (Specify) '

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7. Description of Occurrence: -

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• A leak rate calculation indicating a leak rate of approximately 4 gpm

_w as noted at 1340 hours0.0155 days <br />0.372 hours <br />0.00222 weeks <br />5.0987e-4 months <br /> on .0ctob'er 25, 1974. An investigation revealed that the leak was in the area of the "B" cold leg loop. At that time, -

it was not possible to identify an exact cause or source of leakage. ~

Load reduction and shutdown commenced. -

At cold shutdown, the leak was found to be the same weld of the 1-1/2 inch drain line from the "B" cold leg as reported in Abnormal Occunence s

.I Report No. 50-313/74-9. ,

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July 5, 1974 NSP-10, key. O Page 1 of 3

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Abnormal Occurrence Report No. 50-313/74-10 Sheet'la

5. Identification of Occurrence:

Crack in the socket weld on the reactor coolant drain line (CCA-13-1-1/2)

located between "B" steam ge.

erator and "B" reactor coolant pump. The socket weld is located on the downstream side of the stainless steel coupling adjacen* to the RC piping. The affected weld referenced is the

same weld that-was referenced in Abnormal Occurrence 50-313/74-9.

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y Abnormal Occurrence Report No. 50-313/74-10 Sheet 2

8. Designat*on of Apparent Cause of Occurrence:

Design Procedure Manutacture Unusual Service Condition Including Installation / Environmental Construction Component Failure Operator

'Other (Specif'y) X Examination of the affected area was conducted by qualified metallurgists, consultants from Bechtel, Engineering. The section of piping containing the affected weld was removeu. The specimen, consisting of a coupling and segment of piping connecten 3y the affected weld, was forwarded to the B6W 1aboratory for fu'rther analysis . The results of this analysis are expected in the near future and a complete report will be available at that time.

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9. Analysis of Occurrence:

There were no safety implications or hazards to the health and safety of plant personnel or the public, due to prompt identification of the leak i

and cooldown to cold shutdown conditions. -

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10. Corrective Action:

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The section of piping containing the affected weld was removed intact and was forwardcd to the B6W 1aboratory for further analysis. The three similar welds on drain lines in the Reactor Coolant System piping were dye penetrant examined with no indications noted. The results of ,

the laboratory analysis should indicate the cause of tne failure of the affected weld. This will, in turn, provide information to be used in implementing a solution to the problem. ,

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July S, 1974 NSP-fD, Rev. O Page 2 of 3

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Abnormal Occurrence Report No. 50-313/74-10 Sheet 3

11. Failure Data:

The affected weld, as identified in item 5 of this report, had been reported as failing' in Abnormal Occurrence 50-313/74-9.

12. Reviews and Approvals:

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

Plant Superintendent Yes (X) No ( ) --

Reference:

'JWA-635 Date: 11/1/74 Reviewed by:_

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Licensing' Supervisor

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s Approved by: 47Nf%/l

/ Safe y'Rev'

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4 Approved by:

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Date: #1 / '7 Magager of Nucicar Servhs / #

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Approved by: (h9f)?(fj

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/ Director of, yer P oduction Approved by: , g Date: // // 7 Y Senior'Vice Prdident ' ' '

LJ July S, 1974 NSP-10. !>av. O ,

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