ML20215K171

Forwards Proposed Topical Rept on Operability Assessment of ASME Section III Piping & Supports After Unanticipated Loadings & Low Cycle Fatigue Assessment of ASME Section III Class 2/3 Piping for Unanticipated Loads. Fee Paid

ML20215K171
Person / Time
Site:	LaSalle
Issue date:	10/08/1986
From:	Allen C COMMONWEALTH EDISON CO.
To:	Harold Denton Office of Nuclear Reactor Regulation
Shared Package
ML20215K172	List: ML20215K171 ML20215K177 ML20215K183
References
2224K, NUDOCS 8610280008
Download: ML20215K171 (2)

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}') Address Reply to: Post Off ce Box 767~

72 West Adams Street, Chicago, Illinois

\,_/ Chicago, Ilknois 60690 0767 October 8, 1986 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555 l

Subject:

LaSalle County Station Units 1 and 2 Operability Assessment criteria for Piping Systems NRC Docket Nos. 50-373 and 50-374

Dear Mr. Denton:

Attached is a copy of the proposed " Topical Report on Operability Assessment of ASME Section III Piping and Supports After Unanticipated Loadings".

The operability criteria for piping systems was developed in response to questions raised by the NRC-Region III. During the engineering evaluation of failed snubbers during Unit 1 first refuel, some analyses which assumed snubbers were locked perfectly rigid indicated that stresses in the pipe exceeded ASME Code allowables. Therefore, an alternative stress criteria based on Mark 1 fatigue tests was used to verify that the piping remained capable of meeting its designed service. Substantial time and effort was necessary to explain the alternative criteria to Region III and NRR in numerous teleconferences. Region III suggested the criteria be submitted to NRR for their review prior to Unit 2 first refuel.

The purpose of the operability criteria is to document the approach used to assess the impact of unanticipated loads on a piping system where ASME Code allowables have been exceeded. The operability criteria addresses all piping system components including support components and main structural elements. The operability criteria details the steps required to demonstrate operability of a piping system after being subjected to unanticipated loads (waterhammer, snubber lock-up, etc.). 1 l

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Mr. H. R. Denton October 8, 1986 In accordance with 10 CFR 170, a fee remittance in the amount of

$150.00 is also enclosed.

Please direct any questions you may have regarding this matter to this office.

One signed original and ten (10) copies of this letter and its attachments are provided for yeur use.

Very truly yours, Ol w C. M. Allen Nuclear Licensing Administrator 1m Attachments cc: Dr. A. Bournia - NRR Resident Inspector - LSCS 2224K