ML20209B206

Comments on Review of Design Reverification Program.Piping Problems Will Be Based on as-built Condition

ML20209B206
Person / Time
Site:	Diablo Canyon
Issue date:	12/22/1981
From:	Bosnak R Office of Nuclear Reactor Regulation
To:	Vollmer R Office of Nuclear Reactor Regulation
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Download: ML20209B206 (2)

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UNITED STATES

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DEC 2 ? 1981 NOTE T0: Richard H. Vollmer, ['irector Division of Engineering FROM:

Robert J. Bosnak, Chief Mechanical Engineering Branch, DE

SUBJECT:

DIABLO CANYON COMMENTS ON THE REVIEW 0F DESIGN REVERIFICATION PROGRAM It should be clearly stated that piping problems will be based on the as-built condition. Models should be developed from isometrics which have been verified to represent the system "as-built". The computer code used for analysis of these problems should be benchmarked to the NRC prob 1 cms or have been previously accepted by us.

(Sec.5.4.2) Verification should be made that the input loads, in addition to seismic, have been correctly included.

In the review of the design specifications, design reports and associated design documents as discussed in Section 3.1.1, the changes made to update to as built configurations should be verified.

When' performing piping requalification, the acceptance-rejection criteria should include both piping and supports i.e., a failure of either constitutes a problem failure (Sections 5.4.2 and 5.4.3 should be combined). Supports for large components such as tanks, heat exchangers, pumps, vessels (Sec. 5.4.5), cther than piping, should be included in the reanalysis program.

Table 1 which states samplo size needs further discussion to judge whether there is a valid statistical bases for these size selections.

In addition, the procedure to be followed in the event of a sample failure for each type of mechanical components or :,ystem(i.e., the philosophy of Section 5.3)should be clearly described in terms of the items of Section 5.4 It is assumed Sec. 5.4.4 covers both conduit and cable tray supports. The reverification program acceptance-rejection criteria requires further dis-cussion to determine whether RGl.100 is being properly applied.

This corrent also applies to small bore piping covered in Sec. 5.4.2.

The amount of involvement by TES in the IEB 79-14 review of Diablo Canyon 1 is not clear and should be verified for potential conflict of interest in this area.

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. The program review findinJs by TES should be submitted in parallel at the same time to NRC and PG&K.

Robert J. Bosnak, Chief Mechanical Engineering Branch Division of Engineering cc:

J. Knight F. Cherny M. Hartzman E. Sullivan l

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