ML20215B790

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Forwards Evaluation Rept of Main Steam Pipe Wall Thickness, Describing Fatigue & Finite Element Analyses Performed on Affected Piping,Per ASME Boiler & Pressure Vessel Code.Affected Piping Will Be Reexamined in 1988
ML20215B790
Person / Time
Site: Trojan File:Portland General Electric icon.png
Issue date: 06/11/1987
From: Cockfield D
PORTLAND GENERAL ELECTRIC CO.
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20215B794 List:
References
TAC-65472, NUDOCS 8706170451
Download: ML20215B790 (1)


Text

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ammum Portland General ElectricCorpEnTy

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David W. Cockfield Vice President, Nuclear June 11, 1987

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Trojan Nuclear Plant

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Docket 50-344 i

License NPF-1 i

U.S. Nuclear Regulatory Commission

. ATTN:

Document Control Desk j

Washington DC 20555 l

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Dear Sir:

-l Main Steam Line Wall Thickness I

During'the 1987 refueling outage, inspections were performed for the purpose of identifying areas of erosion / corrosion in secondary system piping. Por-tions of the main steam lines were included in these inspections. While j

performing ultrasonic wall. thickness measurements on the "B" main steam j

line, an area at the outlet of the steam flow venturi was identified as being below the specified minimum wall thickness.

Further examination revealed the same condition exists at the venturi outlet for the "A",

"C",

and "D" lines.

l The cause of the wall thickness discrepancy was machining of the pipe spool in preparation for installation of the venturi.

In order to demonstrate the acceptability of continued use of the affected piping, fatigue and finite element analyses were performed in accordance

.with Section III of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code. These analyses are described in Attachment A.

As further verification that wall thinning is not occurring in the area, the affected piping will be reexamined in 1988.

Sincerely, I

Attachment c:

Mr. John B. Martin Regional Administrator, Region V

. U.S. Nuclear Regulatory Connission Mr. R, C. Barr 1RC Resident Inspector Trojan Nuclear Plant l

Mr. David Kish, Director State of Oregon q

Department of Energy 8706170451 870611 PDR ADOCK 05000344

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121 S.W Salrron SUeet Pomand. Oregon 97204