ML092190140

Comment (6) of Lee F. Goyette on Behalf of Diablo Canyon Opposing Draft Regulatory Guide DG-1192

ML092190140
Person / Time
Site:	Diablo Canyon
Issue date:	08/04/2009
From:	Goyette L Pacific Gas & Electric Co
To:	Rulemaking, Directives, and Editing Branch
References
DG-1192, RG-1.147
Download: ML092190140 (1)

Text

NRCREP Resource From: Goyette, Lee [LFG1@pge.com]

Sent: Tuesday, August 04, 2009 4:43 PM To: NRCREP Resource Cc: tckoser@stpegs.com; Parker, Larry M; Grozan, Thomas C; Westcott, Susan; Sharp, Loren; SCARTH Doug; Ketelsen, Stan C

Subject:

Comments on Draft Regulatory Guide DG-1 192 NRC Rulemaking, Directives, and Editing Branch, Code Case N-597-2, "Requirements for Analytical Evaluation of Pipe Wall Thinning,Section XI, Division 1," is the result of years of discussion, research and testing supported by industry and NRC. It provides a clear, conservative methodology -- based entirely on Construction Code rules -- for the evaluation of non-planar pressure-boundary degradation. It is aimed at avoiding the plant shutdown and its inherent challenge to safety systems unless truly necessary. Yet today, some eleven years after the March 1998 ASME Code approval of Case N-597, Revision 0, the similar N-597-2 continues to be listed as "conditionally acceptable" in the proposed Revision 16 of Regulatory Guide 1.147.

While members of the ASME B&PV Code Section XI Working Group on Pipe Flaw Evaluation continue to work with NRC staff toward achieving approval of the Case, I would like to add the following comment for the perspective it presents:

Draft Regulatory Guide DG-1 192, Table 2, Code Case N-597-2, Condition (2) will require NRC review and acceptance for any amount of local degradation beyond that calculated by the hoop stress equation. Yet DG-1 192, Table 1 finds local degradation -- well beyond the hoop stress limit, up to and including through-wall leakage -- acceptable without NRC review and acceptance via Code Case N-513-2, "Evaluation Criteria for Temporary Acceptance of Flaws in Moderate Energy Class 2 or 3 Piping,Section XI, Division 1."

Granted, the application of N-513-2 is limited to moderate-energy Class 2 and 3 piping; but, the mechanics are the same and the evaluative equations are identical in both Cases. This shared similarity in concept and approach is deliberate.

May I suggest the disparity in NRC approval deserves further consideration.

Le e 4!

Lee F. Goyette, P.E.

Pacific Gas and Electric Company 7~{/~

Diablo Canyon Power Ptant P.O. Box 56 MS 201/113 6

Avita Beach, CA 93424 805-545-6523, -6605 fax LFG1pge.com 0.

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