ML19320A150

RO 50-313/77-5A:on 770128,pinhole Leak Observed on pipe-to- Flange Weld Between Valve & Seal During Routine Investigation.Cause Unknown.Defective Weld Repaired During Refueling Outage

ML19320A150
Person / Time
Site:	Arkansas Nuclear
Issue date:	04/08/1977
From:	Mardis D ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML19320A146	List: ML19320A145 ML19320A150 ML19320A152 ML19320A155
References
NUDOCS 8004140743
Download: ML19320A150 (4)

Text

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OCENSEE EVENT REPORT ~.

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1. Reportable Occurrence Report No. 50-313/77-5A

2. Report Date: 4-8-77 3. Occurrence Date: 1-28-77 1

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

5. Identification of Occurrence:

A leak on the pipe to flange weld between valve RBV-77B and "B" RCP seal.

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6. Conditions Prior to Occurrence:

Steady-State Power Reactor Power 0 MWth Hot Standby Net Output 0 gwe Cold Shutdown Percent of Full Power 0  %

Refueling Shutdown Load Changes During Routine Power Operation Routine Startup Operation Routine Shutdown Operation Other (specify) Hot Shutdown

7. Description of Occurrence: -

At approximately 0200 hours0.00231 days <br />0.0556 hours <br />3.306878e-4 weeks <br />7.61e-5 months <br /> on January 28, 1977, during a routine walk-through inspection by Operations Personnel prior to cooldown, a pinhole leak was observed on the pipe-to-flange weld between Valve RBV-77B and "B" RCP seal. Valve RBV-77B servas as a means of 6nting the "B" RCP seal during initial fill of the RCS. The leak could not be isolated. -

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_) Reportable Occurrence Report No. 50-313/77-5A

8. Designation of Apparent Cause of Occurrence:

Design Procedure Manufacture Unusual Service Condition Including Environmental Installation /

Construction Conn onent Failure (See Failure Data)

Operator Other (specify) , X ,

Unknown

9. Analysis of Occurrence:

The Reactor Coolant System leakrate prior to snutdown was approximately '

O.S GPM. Since the leakage was contained in a controlled area, there was no hazard to the health and safety of the public.

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1 Reportable Occurrence Report No. 50-313/77-5A r

10. Corrective Action:

The defective weld was repaired during the recent refueling outage by grinding and rewelding.

! 11. Failure Data:

l This is the second failure in this area. See Abnormal Occurrence I

Report 74-14.

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