ML20006E420

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Requests NRC Approval for Use of Alloy 690 Steam Generator Tube Plugs for Facility,Prior to 900301,pending Final ASME Approval of Code Case for Alloy 690
ML20006E420
Person / Time
Site: Byron, Braidwood, 05000000
Issue date: 02/14/1990
From: Richter M
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9002230104
Download: ML20006E420 (2)


Text

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February 14, 1990

; u U.S. Nuclear Regulatory Commission L

' ATTN! Doctament Control Desk Washington, D.C. 20555 W ,

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Subject:

Byron Station Units 1 and 2 Braidwood Station Units 1 and 2.

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l pv , Request for an Alternative to the U Requirements of 10 CFR 50.55a

j. NRC Docket Nos 50-454/455 and 50-456/457 Dear Sir )

i Commonwealth Edison Company (CECO) has recently been informed by B&W j Nuclear Technologies and Westinghouse Electric Company (Energy Systems) that i NRC generic approval for the use of ASME SB-166, UNS N06690 material (Alloy /,

U 690) in the fabrication of steam generator tube plugs could not be given since  !

the appropriate ASME Code Case (N-474-1) has not been published in its final form. Pending final ASME approval of the Code Case for Alloy 690, CECO requests approval for the use of Alloy 690 steam generator tube plugs at Byron j and Braidwood Stations in accordance with 10 CFR 50.55(a)(3), as an '

alternative to the requirements of 10 CFR 50.55a (Codes and Standards).

Prior to the submittal of this request, twelve (12) Alloy 690  ;

mechanical plugs (Westinghouse plugs) were installed in Braidwood Unit 1

-during the Fall 1989 refueling outage (which ended la December 1989). Ceco "

-reviewed / verified the material properties of the Alloy 690 plugs, prior to -

use, from the aspect of. enhanced protection against plug cracking. Vendor .

notification on the Code Case status was not received prior to usage of the e plugs, which would have prompted this request earlier.

At this time, Byron Unit 1 is presently in a refueling outage which is scheduled to end by March 4, 1990. During this outage, the station is utilizing-plugs (B&W plugs) fabricated from Alloy 690 material. In addition.

Braidwood Station plans to use Alloy 690 plugs (Westinghouse plugs) during the upcoming Unit 2 refueling outage scheduled to begin in March 1990. l Byron and Braidwood Stations are utilizing Alloy 690 steam generator

-tube pluge because they (Alloy 690 plugs) are expected to provide enhanced i protection against the plug cracking concerns associated with the Alloy 600 mechanical plugs. At Byron and Braidwood Stations, it is Ceco's intention to eventually replace all of the susceptible Alloy 600 mechanical plugs based on plug. lifetime assessments performed by CECO. These assessments are performed on all Alley 600 mechanical plugs regardless of the manufacturer.

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h p' .p U.S. Nuclear Regulatory Commission February 14, 1990

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.I i CECO requests NRC approval for the use of Alloy 690 steam generator tube plugs-for Byron and'Braidwood Stations prior to March 1, 1990.

Please direct any questions concerning this request to this office. l t

Respectfully,  ;

9 M. H. Richter 1 Generic Issues Administrator i 1

cc: A.B. Davis - Regional Administrator, Region III S. Sands - Project Manager, NRR P. Shemanski - Project Manager, NRR

'H. Conrad - NRR j E. Murphy - NRR ,

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