ML20058H745

Requests Exemption from 10CFR50.61,since Determination of Initial RT NDT Not Made in Accordance w/NB-2331 of ASME Boiler & Pressure Vessel Code.Nonproprietary Rept Supporting Proposed Alternative Encl

ML20058H745
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	12/03/1993
From:	Simpkin T COMMONWEALTH EDISON CO.
To:	Murley T NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
Shared Package
ML20058H749	List: ML20058H745 ML20058H777
References
NUDOCS 9312130212
Download: ML20058H745 (2)

Text

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Commonwealth Edison hO' 1400 Opus F" ace Downers Groce, hiino:s 60515 December 3,1993 Dr. Thomas E. Murley, Director Office of Nuclear Reactor Regulation U.S. Nuclear R-egulatory Commission Washington, D.C. 20555 Attn:

Document Control Desk

Subject:

Zion Station Units 1 and 2 Request for Exemption to 10CFR50.61 NRC Docket Nos. 50-295 and 50-304

References:

(a) September 1,1993 T. Simpkin letter to Dr. T. Murley (b)

October 5,1993 letter from T. Simpkin to Dr. T. Murley

Dear Dr. Murley,

With Reference (a), Commonwealth Edison Company (CECO) transmitted the results of a revised Pressurized Thermal Shock (PTS) evaluation. The methodology utilized in performing the evaluation was transmitted with R.eference (b). This methodology incorporated changes in the manner in which the initial RT yor was determined, and in the determination of the appropriate chemistry factor to be applied.

The determination of the initial RT was not made in accordance with NB-2331 of xor the ASME Boiler and Pressure Vessei Code, as specified in 10CFR50.61 (b) (2)(i).

Accordingly, CECO is requesting, pursuant to 10CFR50.12, and exemption from the aforementioned provision of 10CFR50.61.

The proposed exemption, if not granted, will result in a significant impact on CECO.

Absent the requested exemption, Zion Station will exceed the screening criteria for pressurized thermal shock prior to expiration of the operating licenses. This will result in a significant expenditure of resources to justify continued operation, or the premature retirement of the units.

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Dr. Murley December 3,1993

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The alternative proposed in lieu of strict compliance with all provisions of the PTS -

rule will achieve the underlying purpose of the rule while allowing the ~ Zion Station units j

to be fully utilized. The proposed alternative utilizes fracture mechanics in lieu the methodology endorsed be ASME NB-2331.

In addition to the Reference (b) submittal, Attachment A contains information in support of the technical adequacy of proposed alternative.

Please direct any questions to this office.

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7 Sincerely, i

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T. W. Simpkin j

Nuclear Licensing Administrator i

i Attachment cc: J. B. Martin, Regional Administrator - RIII C. Y. Shiraki, Project Manager - NRR J. D. Smith, Senior Resident Inspector - Zion I

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