ML20216D378

From kanterella
Jump to navigation Jump to search
Forwards Revised NFM9900022, Braidwood Unit 2 Cycle 8 COLR on ITS Format & W(Z) Function, to Account for Error That W Discovered in Computer Code Used to Calculate PCT During LBLOCA
ML20216D378
Person / Time
Site: Braidwood Constellation icon.png
Issue date: 07/21/1999
From: Tulon T
COMMONWEALTH EDISON CO.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20216D381 List:
References
BWW990044, NUDOCS 9907280017
Download: ML20216D378 (4)


Text

commonw cahh Imon o.mrian) tiraidwoud Generating St.ation l

o Route si, Dox Mi

!! races ille, IL 6(H07%19 l

Tel HI44SK 2301 I

l July 21,1999 BW990044 i

U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Unit 2 Facility Operating License No. NPF-77 NRC Docket No. STN 50-457

Subject:

Revised Core Operating Limits Report for Braidwood Station, Unit 2 Cycle 8

References:

Letter from (Commonwealth Edison Company) to U.S. NRC, " Core Operating Limits Report for Braidwood Station, Unit 2 Cycle 8 (AR208)," dated June 10, 1999.

The Braidwood Station, Unit 2, Core Operating Limits Report (COLR) has been revised to account for an error that Westinghouse Corporation discovered in their computer code (i.e.,

LOCBART) used to calculate Peak Clad Temperature (PCT) during a Large Break Loss Of Coolant Accident.

Westinghouse Corporation has concluded that acceptable PCT can be ensured provided:

fuel assembly average burnup is greater than or equal to 4000 MWD /MTU, or e

heat flux hot channel factor (i.e., F(Q)) is less than or equal to 2.45.

Braidwood Station, Unit 1 Cycle 8 has exceeded an fuel assembly average burnup of 4000 MWD /MTU for all of the fuel assemblies in the core, therefore it is presently acceptable.

Braidwood Station, Unit 2 has fuel assemblies less than 4000 MWD /MTU, however the design calculations predict F(Q) to be less than or equal to 2.387. In order to ensure the design predictions and the assumption that Braidwood Station, Unit 2 Cycle 8 has acceptable PCT margin are valid, the COLR is being revised to further restrict F(Q) until the time the fuel assembly average burnup is greater than or equal to 4000 MWD /MTU. This COLR revision provides a more restrictive limit to compare measured F(O) to during the monthly surveillance.

The change to the COLR to ensure F(Q) remains less than 2.45 is accomplished by revising the normalized F(Q) (i.e., K(Z) curve). The K(Z) curve is designed to be a correction factor that penalized portions of the core as a function of core height to account for core reflood considerations. For this application, the K(Z) curve is being used as a correction factor that l

is more limiting than the previous K(Z) curve.

~

9907280017 990721 PDR ADOCK 05000457-r P

PDR U UU56:

.unicom n,msny L.

1 i

. July 21,1999

+

U. S. Nuclear Regulatory Commission Page 2 The change to the COLR was done under the provisions of 10 CFR 50.59 and is being transmitted to you in accordance what Technical Specification 5.6.5, " CORE OPERATING LIMITS REPORT (COLR)."

Should you have any questions conceming this matter, please contact T. W. Simpkin, Regulatory Assurance Manager, at (815) 458-2801, extension 2980.

Respectfully, l

l

/A-T othy J. Tulon i

ite Vice President

)

Braidwood Station 1

TJT/DC/dah

Attachment:

Braidwood Station, Unit 2, Core Operating Limits Report for Cycle 8 Cc:

Regional Administrator-NRC Region ll1 NRC Senior Resident Inspector-Braidwood Station i

t P:Vleptsveg amance\\995ettersva99024. doc

4 Bec:

NRC Project Manager-NRR - Braidwood and Byron Stations Nicholas Reynolds-Winston & Strawn Office of Nuclear Facility Safety-IDNS Site Vice President-Braidwood Station Regulatory Assurance Manager-Braidwood Station Director, Licensing and Compliance - Braidwood and Byron Stations Comed document Control Desk Licensing (Hard Copy)

Comed Document Control Desk Licensing (Electronic Copy)

I' l

l l

l PMeptsveg assurance \\99iettersVa99024 doc

Attachment Braidwood Station, Unit 2, Core Operating Limits Report for Cycle 8 (AR208)

P Wep'sveg assuranceG9lettersva99024 doc