ML20151W140

Forwards Rev 2 to Calculation BYR98-109/BRW-98-0339-E, Base Line Ampacity Values for Std Fire Wrap Configurations. NRC Representatives Also Specifically Requested Revised Calculation Be Submitted

ML20151W140
Person / Time
Site:	Byron, Braidwood
Issue date:	09/08/1998
From:	Krich R COMMONWEALTH EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20151W144	List: ML20151W140 ML20151W180
References
NUDOCS 9809150195
Download: ML20151W140 (3)

Text

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Commonweahh lidison Company '

1400 Opus Place Downers Grove, il t>0515-5701 September 8,1998 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 - 0001 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455 Braidwood Station, Units 1 and 2 Facility Operating License Nos. NPF-72 and NPF-77 NRC Docket Nos. T so-456 and STN 50-457

Subject:

Revised Thermo-Lag Ampacity Derating Factor Calculation

Reference:

Letter from J. B. Hosmer (Commonwealth Edison Company) to U. S. l Nuclear Regulatory Commission," Response to the NRC Request for Additional Information Regarding Ampacity Derating Analyses," dated September 19,1997.

The referenced letter provided the Commonwealth Edison (Comed) Company response to an NRC request for additional information (RAI) on the analytical models used to establish the ampacity derating for fire-protected cables at Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2. In a subsequent teleconference on February 2,1998, representatives of the NRC noted that all issues addressed in the RAI were resolved with the exception of one issue (i.e., the use of two different thermal analyses models for the baseline and cladded fire barrier configurations to derive the ampacity derating ratio). In the teleconference, representatives of the NRC requested that Comed revise calculation BYR 96-082/BRW 96-194, "Ampacity Derating ihr Standard Fire Wrap Configurations," to be internally consistent in the comparison of fi.e barrier configurations. The NRC representatives also specifically requested that the revised calculation be submitted along with this revised response. , O'}

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PDR ADOCK 05000454 p PDR A Unicum Company

USNRC September 8,1998 The thermal analyses models used in the determination of the ampacity derating factors for fire-protected cables, cable trays, and conduits at Byron Station, Units 1 l and 2, and Braidwood Station, Units I and 2, have been revised. The new calculation, BYR 98-109/BRW 98-339-E, " Base Line Ampacity Values for Standard Fire Wrap Configurations," that documents the reanalysis is an enclosure to this letter. The reevaluation of fire-protected cables at Byron Station, Units 1 and 2, and Braidwood Station, Units 1 and 2, utilizing the revised ampacity derating factor has determined .;

that all cable routing points are acceptable.

1 Please address any comments or questions regarding this matter to Mr. David J.

Chrzanowski at (630) 663-7205.

l Respectfully,  !

A' R. M. ' ch Vice President - Regulatory Services

Enclosure:

BYR 98-109/BRW 98-339-E," Base Line Ampacity Values for Standard Fire Wrap Configurations."

cc: Regional Administrator-USNRC, Region Ill NRC Senior Resident Inspector-Braidwoed Station NRC Senior Resident Inspector-Byron Station i

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GM) ave \LIC-98 Il5. doc i

Enclosure 1 l

BYR 98-109/BRW 98-339-E

" Base Line Ampacity Values for Standard Fire Wrap Configurations" l

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