ML20084B752

Submits Info Re Plugging of Two Steam Generator Tubes on 770320.Generator Insp Program Planned for Spring 1977 Refueling Outage Encl

ML20084B752
Person / Time
Site:	Turkey Point
Issue date:	03/25/1977
From:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
To:	Lear G Office of Nuclear Reactor Regulation
Shared Package
ML20084B707	List: L-77-228, Forwards Rept on Sys Disturbance 770516 ML20084B704 ML20084B732 ML20084B752
References
L-77-94, NUDOCS 8304070074
Download: ML20084B752 (4)

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P. O. DOX 011100 MIAMI, FL 33101

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FLORIDA POWER & LIGHT CO".U'At4Y f

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March 25, 1977 ,

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Office of Nuclear Reactor Regulation N 7/

Attn: George Lear, Chief J Operating Reactors Branch #3 f j Division of Operating Reactors U. S. Nuclear Regulatory Commission E CNe

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d Washington, D. C. 20555 n M a [~ hg

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Dear Mr. Lear:

\\ Ah6 9 .c 4 ' i Re: Turkey Point Unit No. 4 !E F]IE.M g # -

Docket No. 50-251 D g

' j As we discussed during our phone conversation of March 25, Q 3

1977, this letter is forwarded to provide information con-cerning Point Unit theNo.plugging

4. of two steam generator tubes in Turkey d On March 20, Unit 4 was shut down to plug a leaking steam generator tube.

During this outage, a second leaking tube. ,

was discovered and was also plugged. Since both leaking '

tubes have been successfully plugged, the unit is now ready f to be returned to power operation. ']

We, at Florida Power & Light Company in consultotion with the NSSS Vendor, have reviewed the above situation and have f

concluded that resumption of power can be effected in a safe k

( manner the public.

and that continued operation presents no danger to y We have concluded that the leaks observed during f ;

this outage are similar to those previously observed in both Units 3 and 4 and, thus, do not present a new type of failure.  :

Leakage was first observed in mid-Pebruary and progressed in '

an orderly fashion over a period in excess of one month. These  ;

leaks behaved in a predictable manner and, thus, presented no danger to the public. This type of leak behavior has been  ?'

observed previously in these general locations. In addition, '

we have a program which will definitively determine the loca- i tion of the leak in tube R-45, C-53, which is wherci <the >

recent 4C.

leakage has occurred in Turkey Point 4 Steam Generator -

This program will be conducted during the 1977 spring l refueling outage of our Turkey Point Unit No. 4. A detailed summary of this program is provided in the attachment .

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In addition, Florida Power & Light Company and the' SSS -

Vendor are continuing to investigate possible ways to remove'-. -

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To: George Lear, NRC March 25, 1977 I.' '

Ra: Turkey. Point Unit No. 4 Page , ...

Docket No. 50-251 1

. 1 cn appropriate portion of the tube R-45, C-53, if 'necessa'ry. '.

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Very.truly yours, _ ,

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tw~ 4 *1 ber,t E. Uhrig "

, Vice President '/ . ' .

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Attachment c /

' cc: Robert Lowenstein, Esq. ,

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TURKEY POINT UNIT NO. 4 STEAM GENERATOR INSPECTION PROGRAM PLANNED FOR SPRING 1977 REFUELING

1. Sludge maps utilizing standard oddy current technique will be made as follows:

a) Every other tube will be probed in rows 7, 14, 21, 28, 33, and rows 38 through 45 between columns 15 and 78.

b) Sludge Mapping will be performed in all three steam generators. ,

2. A complete Regulatory Guide 1.83 inspection will be per-formed.

3. Eddy current inspection will be performed in' the one o' clock and 11 o' clock wedge regions to detect flaws in the tubes.

This inspection will be conducted using a standard probe, but we also plan to include selective use of the helical scan p obe which is under development and scheduled to be field tosted in early April, 1977. This testing will be performed -

in all three steam generators.

4. An eddy current dont location program will be performed as follows:

A comprehensive full dent program is planned for one a) steam generator. Steam generator "C" has tentatively been selected.

b) A representative program is planned for the remaining two steam generators.

c) We expect to use a standard .540 inch diameter probe at reduced gain.

5. Tube gauging will be conducted on all three steam generators utilizing three different size oddy current probes (.540 in.,

.610 in., and .650 in. diameters).

6. A program to definitely determine the location of the leak in the 4C steam generator tube R-45, C-53 has been developed which includes:

a) A topside entry into "C" steam generator.

b) Cutting tube R-45, C-53, above the uppermost tube support plate.

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i c) Eddy current testing through the open tube end using a standard probe. The helical scan probe currently scheduled for field testing in early April is also planned to be used, d) Tube gauging utilizing the .540 in., .610.in., and

.650 in., diameter probes. ,

. c) Development of a probe that can be used to selectively pressurize short lengths of the tube with water and/or air to locato leaks by pressure decay or other means.

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