ML19031B401
| ML19031B401 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 03/31/1975 |
| From: | Mittl R Public Service Electric & Gas Co |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| References | |
| Download: ML19031B401 (2) | |
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Public Service Electric and Gas Company 80 Park Place Newark, N.J, 0710:1 Phone 201 /62~2-7000-March 3l, l975 JlEGJ1l;A fir*i,n,,.._,,.~
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Mr. A. Giambusso, Director* - -*-
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Division of Reactor Licensing
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Washington, D. c.
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Dear Mr. Giambusso:
STEAJ.Vl NO. l SALEM GENERATOR TUBE EXPANSION r:~~
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AND 2 UNITS
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, I AUTHORIZATION A-6267.l
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DOCKET NOS. 50-272 AND 50-3ll
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Beginning in mid-April, l975, the steam generator tubes of Salem No. 1 and 2 Units will be explosively expanded with.in the tube-sheets.
The expansion operations were recommended by Westinghouse and will be implemented under their direction on-site.
The process, called WEXTEX by Westinghouse, involves detonating
-pol:vethelene-covered explosive charges witbLn the l\\T:i.-i:r-H'P.
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thereby reducing the tube-to-tubesheet crevice from approximately 0.0075-inches (radially) to O.OOl-inch.
The motivation for reducing th~ crevices is additional conservatism of design with respect to possible accumulation of corrosion-inducing impurities in the crevices.
The WEXTEX explosive tube expansion process was first applied at the Diablo Canyon No. 1 Unit of Pacific Gas and Electric Company.
The plant was instrumented with accelerometers, strain gages, pressure transducers, and other sensors, and the results of that test program have revealed no adverse effects upon NSSS equipment.
Similar processes utilizing substantially more pawer-ful explosive charges are commonly used in manufacturing similar heat exchangers.
New Westinghouse steam generators h.ave mechan-ically rolled tubes to limit tube-to-tubesheet crevices, but earlier vessels, like those at Salem, are having this design improvement retrofitted in the field using the WEXTEX process.
All other assembly of the vessels has been completed and only the field hydrostatic tests remain.
These tests will be per-formed after tube expansion.
Following the tube expansion program, the tests listed below will be performed to assure continuing steam generator integrity:
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Liquid penetrant test of divider-plate welds.
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The Energy People 95-2001 250M 8-74
Mr. A. Giambusso, Director 3-31-75
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A complete eddy current test uf tubes (for Regulatory Gu.ide 1. 83).
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Primary and second~_:r..y side field hydrostatic tests.
We will continue to monitor and audit the WEXTEX operations.
We believe that this process will contribute to improved steam generator reliability with no adverse effects or safety impli-cations.
Very truly yours,
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R. L; Mittl General Manager - Projects Projects Department