ML20072N249
| ML20072N249 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 08/26/1994 |
| From: | Simpkin T COMMONWEALTH EDISON CO. |
| To: | Russell W NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9409060045 | |
| Download: ML20072N249 (4) | |
Text
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1400 Opus Place
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Downers Grove, Illinois 60515
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August 26,1994 Mr. William T. Russell, Director Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Attention: Decument Control Desk
Subject:
Byron Station Unit 1 Correction to Annual 10 CFR 50.46 Report NRC Docket No. 50-454
Reference:
T. Simpkin letter to W. Russell dated July 8,1994
Dear Mr. Russell:
With the reference letter, Commonwealth Edison Company (Comed) supplied the annual report detailing the Loss of Coolant Accident (LOCA) Peak Clad Temperature (PCT) rack up for Zion, Byron, and Braidwood Stations. This report was submitted accordance with the provisions of 10 CFR 50.46 (a)(3)(ii).
Westinghouse subsequently notified Comed that two PCT penalties had been omitted from the 1993 Westinghouse annual report; specifically, both penalties were associated with assembly guide pins. The PCT penalty due to the upper internals assembly guidepin flakes was omitted from the Comed report.
The other PCT penalty, due to the assembly guidepin removal (5 F), had previously been included in the report.
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Mr. Russell August 24,1994 Attachment I to this letter contains the corrected PCT rack-up sheet for Byron Unit 1. The correction reports an additional 6 F peak clad temperature (PCT) penalty for the Byron Station Unit 1 Large Break LOCA. This penalty is due to the potential presence of assembly guidepin flakes / fragments in the reactor coolant system. Attachment 2 contains an additional note which describes the PCT penalty associated with the assembly guidepin flakes.
Please direct any questions to this office.
Sincerely, Qbd T.W. Simpkin Nuclear Licensing Administrator Attachments cc:
J.B. Martin, Regional Administrator - Region III G.F. Dick, Jr., Project Manager - NRR H. Peterson, Senior Resident Inspector - Byron k nla:rion:082694.2
Commonwealth Edison Company 1994 Annual 10 CFR 50.46 Report (Revision 1)
PLANT NAME:
Byron Station Unit 1 ECCS EVALUATION MODEL:
Large Break LOCA REPORT REVISION DATE:
06/01/94 CURRENT OPERATING CYCLE: fi ANALYSIS OF RECORD Evaluation Model: BASH Calculation: Westinghouse SEC-SAll 315 7-CO, July,1989 Fuel: VANTAGE 517 x 17 FQ - 2.50 FNAH - 1.65 SGTP-15%
Reference PCT PCT - 1883.1*F MARCIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS Fuel Rod Initial Condition inconsistency (Note 1)
APCT -
+ 10. 0'F Economic Generation Control (Note 4)
APCT-
+4.0'F SG Tube Seismic /LOCA Assumption (Note 6)
APCT -
+ 7. 2
- F Containment Mini-Purge Assurnption (Note 7)
APCT -
+ 1. 0* F LB-LOCA Power Distribution (Note 9)
APCT - +100.0*F Removed Upper Internal Assembly Alignment APCT -
+ 5.0*F Pins (Note 10)
Assembly Culde Pin Flakes (Note 13)
APCT-
+ 6. 0*F B. CURRENT LOCA MODEL ASSESSMENTS None NET PCT PCT - 2016.3*F
Commonwealth Edison Company 1994 Annual 10CFR50.46 Report Table Notations (Additional Note) 13.
Assembly Guide Pin Flakes Bending of fuel assembly alignment pins to angles greater than 5 degrees may result in the generation of pin flakes or fragments. The flakes could potentially lodge themselves in an assembly and locally reduce assembly flow. The flakes could increase blockage of the hot rod subchannel during the reflood period and increase the PCT. This penalty is only applicable to Byron Station Unit 1.
1