ML033360612

Plant Specific ECCS Evaluation Changes 0 10 CFR 50.46 Report

ML033360612
Person / Time
Site:	Dresden
Issue date:	11/25/2003
From:	Hovey R Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RHLTR: #03-0077
Download: ML033360612 (4)

Text

.- Dresden GeneratingtationExelnem Exelon Generation www.exeloncorp.com Nuclear Dresden Generating Station 6500 North Dresden Road Morris, IL60450-9765 Tel 815-942-2920 November 25, 2003 10 CFR 50.46(a)(3)(ii)

RHLTR: #03-0077 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249

Subject:

Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report

Reference:

Letter from R. J. Hovey (Exelon Generation Company, LLC) to U. S. NRC, Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report," dated November 25, 2002 In accordance with 10 CFR 50.46, "Acceptance criteria for emergency core cooling systems for.

light-water nuclear power reactors," paragraph (a)(3)(ii), Exelon Generation Company (EGC),

LLC, is submitting this letter and its attachment to meet the annual reporting requirements.

Dresden Nuclear Power Station Units 2 and 3 is maintaining the same emergency core cooling (ECCS) model as reported in the referenced letter. Two minor errors were discovered by the fuel vendor (General Electric (GE)). The first error involved incorrect initial water levels used in the SAFER model. The second error involved an incorrect initial steam separator pressure drop input used in the SAFER model. GE Determined the peak clad temperature (PCT) impact of these errors on all fuel types in Dresden Units 2 and 3 to be negligible. The PCTs of record are being provided as an attachment to this letter.

If there are any questions concerning this letter, please contact Mr. Jeff Hansen at (815) 416-2800.

Respectfully,

/u.

Robert J Hovey Site Vice Presiden Dresden Nuclear Power Station

Attachment:

Dresden Nuclear Power Station Units 2 and 3 - 10 CFR 50.46 Report cc: Regional Administrator - NRC Region III u0 NRC Senior Resident Inspector - Dresden Nuclear Power Station

Attachment Dresden Nuclear Power Station Units 2 and 3 10CFR50.46 Report PLANT NAME: Dresden Nuclear Power Station, Unit 2 ECCS EVALUATION MODEL: SAFER/GESTR-LOCA REPORT REVISION DATE: 10/24/2003 CURRENT OPERATING CYCLE: 18 ANALYSIS OF RECORD Evaluation Model: The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident, Volume ll, SAFER/GESTR Application Methodology, NEDE-23785-1-PA, General Electric Company, Revision 1, October 1984.

Calculations:

"SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis for Dresden Nuclear Station 2 and 3 and Quad Cities Nuclear Station Units 1 and 2," NEDC-32990P, Revision 1, GE Nuclear Energy, September 2001.

Fuel: 9x9-2, ATRIUM-9B and GE14 Limiting Fuel Type: GEl4 Limiting Single Failure: Diesel Generator Limiting Break Size and Location: 1.0 Double-Ended Guillotine in a Recirculation Suction Pipe Reference Peak Cladding Temperature (PCT) PCT= 21100 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated December 6, 2001 (See Note 1) l APCT = 00 F 10 CFR 50.46 report dated November 25, 2002 (See Note 2) l APCT = 00 F Net PCT l 2110 F B. CURRENT LOCA MODEL ASSESSMENTS SAFER LevelNolume Table Error (See Note 3) APCT = 0 F SAFER Initial Steam Separator Pressure Drop Error (See Note 4) APCT = 0 0F Total PCT change from current assessments XAPCT = 0 F Cumulative PCT change from current assessments E APCT I=

0°F Net PCT 2110 F

fAttaci hmnt Dresden Nuclear Power Station Units 2 and 3 10CFR50.46 Report PLANT NAME: Dresden Nuclear Power Station, Unit 3 ECCS EVALUATION MODEL: SAFER/GESTR-LOCA REPORT REVISION DATE: 10/24/2003 CURRENT OPERATING CYCLE: 18 ANALYSIS OF RECORD Evaluation Model: The GESTR-LOCA and SAFER Models for the Evaluation of the Loss-of-Coolant Accident, Volume 1II, SAFER/GESTR Application Methodology, NEDE-23785-1-PA, General Electric Company, Revision 1, October 1984.

Calculations:

"SAFER/GESTR-LOCA Loss-of-Coolant Accident Analysis for Dresden Nuclear Station 2 and 3 and Quad Cities Nuclear Station Units 1 and 2," NEDC-32990P, Revision 1, GE Nuclear Energy, September 2001.

Fuel: 9x9-2, ATRIUM-9B and GE14 Limiting Fuel Type: GE14 Limiting Single Failure: Diesel Generator Limiting Break Size and Location: 1.0 Double-Ended Guillotine in a Recirculation Suction Pipe Reference Peak Cladding Temperature (PCT) PCT = 21100 F MARGIN ALLOCATION A. PRIOR LOCA MODEL ASSESSMENTS 10 CFR 50.46 report dated November 25, 2002 (See Note 2) APCT =0 0 F Net PCT 2110 F B. CURRENT LOCA MODEL ASSESSMENTS SAFER LevelNolume Table Error (See Note 3) APCT = 0F SAFER Initial Steam Separator Pressure Drop Error (See Note 4) APCT = 00F Total PCT change from current assessments YAPCT = 00 F Cumulative PCT change from current assessments E APCT I= 0F Net PCT 2110 0F

Attachment Dresden Nuclear Power Station Units 2 and 3 10 CFR 50.46 Report

1. Prior LOCA Model Assessment The 50.46 letter dated December 6, 2001 reported a new LOCA analysis to support extended power uprate (EPU) and transition to GE14 fuel for Dresden Unit 2 Cycle 18.

The same report assessed impact of errors in Framatome ANP LOCA analysis model for Dresden Unit 3 Cycle 17 at pre-EPU power level.

[

Reference:

Letter from Preston Swafford (PSLTR: #01-0122) (Exelon) to USNRC, Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report," December 6, 2001.]

2. Prior LOCA Model Assessment Unit 3 implemented GE LOCA analysis and GE14 fuel with Dresden Unit 3 Cycle 18 startup on October 25, 2002. Therefore, both Dresden Units 2 and 3 are being maintained under the same LOCA analysis. In the referenced letter, the impact of GE LOCA error in the WEVOL code was reported for Dresden Units 2 and 3 and determined to be negligible.

[

Reference:

Letter from Robert J. Hovey (RHLTR: #02-0083) (Exelon) to USNRC, Plant Specific ECCS Evaluation Changes - 10 CFR 50.46 Report," November 25, 2002.]

3. Current LOCA Assessment GE reported that an error was found in the initial level/volume table for SAFER. The level/volume tables were generated with incorrect initial water levels. This resulted in an incorrect volume split in the nodes above and below the water surface, and incorrect initial liquid mass. GE determined that the PCT impact of this error on all fuel types in the Dresden reactors to be negligible.

[

Reference:

10 CFR 50.46 Notification Letter, 2003-01, May 6, 2003.]

4. Current LOCA Assessment GE reported that an error was found in the initial steam separator pressure drop input to the SAFER model. The calculation of this value for some plant/fuel types applied the wrong loss coefficient or erroneously included a term to account for the hydrostatic pressure. These errors resulted in a higher initial steam separator pressure drop and overly restricted the flow through the separator during the LOCA event. GE determined that the PCT impact of this error on all fuel types in the Dresden reactors to be negligible.

[

Reference:

10 CFR 50.46 Notification Letter, 2003-03, May 6, 2003