ML20084C528

AO 251-74-7:on 741029,routine Visual Insp of RCS Revealed Steam Leaking from 3/4-inch Vent Line Assembly Upstream of Safety Injection Sys.Cause Unknown.Vent Assembly Removed & Sent for Metallurgical Analysis.Supplemental AO Will Follow

ML20084C528
Person / Time
Site:	Turkey Point
Issue date:	11/08/1974
From:	Schmidt A FLORIDA POWER & LIGHT CO.
To:	Case E Office of Nuclear Reactor Regulation
Shared Package
ML20084C498	List: ML20084C496 ML20084C528
References
AO-251-74-7, NUDOCS 8304080091
Download: ML20084C528 (2)

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f November 8, 1974

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Mr. Edson G. Case, Acting Director s

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7 U. S. Atomic Energy Commission Washington, D. C. 20545

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Dear Mr. Case- ,

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ABNORMAL OCCURRENCE NO. 251-74-7 'Q Q- ~ 7, ,

NOVEMBER 3, 1974 ' -

OCCURRENCE DATE: OCTOBER 29, 1974 TURKEY POINT UNIT NO. 4 SAFETY INJECTION SYSTEM LEAK FROM VENT TiSSEMBLY A. Condition Prior to occurrence: _ ,

A reactor heatup was in progress following cold shutdown.

B. pescription of the Occurrence:

At about 6:30 a.m. October 29, 1974, a routine visual inspection of the reactor coolant system revealed steam leaking from a 3/4 inch vent line assembly upstream of Safety Injection System (SIS) 10 inch check valve 4-875A.

C. Cause of the Occurrence:

The leakage appeared to be confined to the weld area between the 3/4 inch pipe and the socket weld fitting. The cause for the discontinuity has not been determined at this time.

D. Analysis of Occurrence:

In the event that safety injection had been required, the amount of water lost through the leak would have had a neg-ligible effect on the cooling of the reactor core. Thus, neither reactor r,afety nor the health and safety of the public were jeopardized by this occurrence.

E. Corrective Action:

Corrective actions consisted of the following:

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Hr. Edson G. Casd Acting Director V Pcge 2 sc .185vember 8, 1974

1. The 3/4 inch vent assembly was removed from the (SIS) pipe run by grinding off the fitting to pipe weld. The vent assembly was sent to a laboratory for a metallurigical analysis.

2. Prior to welding, the replacement fitting was subjected to liquid penetrant and radiographic examination. The base metal of the SIS pipe was also examined by liquid pene trant c>: amination. Following welding, a successful liquid penetrant examination was conducted on the vent assembly weld connections.

3. Subsequent to heat up and pressurization, a visual examination was made on the vent assembly welds. No leakage was observed.

4. To ensure the integrity of similar vent or drain line assemblies on the Unit 4 safety injection system, liquid penetrant examinations were conducted on these assemblies. Replacement of these assemblics is not required.

5. Unit 3 vcnt and drain assemblies will be examined during the currcnt re fueling outage.

6. A supplement to this Abnormal Occurrence will be issued upon receipt at the report from the laboratory.

F. Failure Data:

This is the first fai]ure of this type at the Turkey Point nuclear units.

Very truly yours, r

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K.- ~ D . Schmidt Director of Power Resources DWR:pg cc: Mr. Norman C. Moseley Jack R. Newman, Esquire