ML19093A981

Purpose of the Letter Is to Present the Surry Unit No. 1 Steam Generator Surveillance Program for the Forthcoming Outage

ML19093A981
Person / Time
Site:	Surry
Issue date:	10/31/1977
From:	Stallings C Virginia Electric & Power Co (VEPCO)
To:	Case E, Reid R Office of Nuclear Reactor Regulation
References
Download: ML19093A981 (4)

Text

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VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND,VIRGINIA 23261 October* 31", 197T :

Mr. Edson G. Case, Acting Director Serial No. 486 Office of Nuclear Reactor Regulation PO&M/TAP: dgt U.S. Nuclear Regulatory Connnission Docket No. 50-280 Washington, D. C. 20555 License No. DPR-32 Attn: Mr. Robert W. Reid, Chief Operating Reactors Branch 4

Dear Mr. Case:

The purpose of this letter is to present the Surry Unit No. 1 steam generator surveil_lance program for the forthcoming outage. The program will consist of the following:

1) An eddy current program will be accomplished from the cold leg side over the U-bends including Rows 1-5, all columns. This is to provide current data for this area.

2) A photography and inspection program through the lower hand-holes will be accomplished. The lowest support plate will be inspected and the flow slots_ gauged.

3) The shell to wrapper annulus gauging program will be accomp-

Lished in "lA" steam generator. This data will be related to previously established strain maps.

4) A tube gauging program similar to previous inspections will be accomplished using various sized eddy current probes.

This gauging program is extremely conservative in that it will require gauging of the major regions of the bundle where tube hoop strains are predicted to be above 12.5%. In fact, tube vulnerability to cracking is not expected to occur in regions where the hoop strains are less than 15% as is demon-s.trated by previous industry wide history of leaky dent occur-rences. This will be accomplished by mapping the occurrences of tubes that cannot pass 0.650", 0.610" and 0.540" probes in the areas indicated on the attached tube sheet diagram. It is anticipated that no 0.610" or 0.540" restrictions will occur in the inspection area outside of the 15% contour and only a few 0.650" restrictions may occur in this area. If the antici-pated pattern of dented tubes in the 12.5% contour area is not verified by the gauging program, the program will be expanded to include all .the 12. 5% contour area. . The map of predicted tube hoop strain for this outage is shown on Figure 2.

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,,VIROiNIA ELECTRIC AND POWER COMPANY TO Mr. Edson G. Case

• Page No. 2 The plugging program and its associated operating period will be forwarded when the surveillance program data has been evaluated.

Very truly yours,

-ZO. )/)7_ \.Jlatt~~tY

. C*. M. Stallings Vice President-Power Supply and Production Operations Attachments (Surry 1 Gauging Program, Figure 1)

(Tube Hoop Strain, Figure 2) cc: Mr. James.P. O'Reilly

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All numbers are inclusive:* *

1) From tube lane out to Row 12 3) Patc11 Plate

2) Wing areas to Row 23, Column 15 4) Outer Areas ... R 28-32 C 15-20 and lower, Column 80 ?nd higher R 28-32. C 75-80 R 32-39 C 33-39 R 32-39 C 56-fi2

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• MAX . 4-6533 4-C) -,

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• .MANWAY Figure 2. Tube Hoop Strain at 5.5 EFPM's

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