SVPLTR 05-0013, Commitments and Plans Related to Extended Power Uprate Operation

Commitments and Plans Related to Extended Power Uprate Operation

ML050970354
Person / Time
Site:	Dresden
Issue date:	03/31/2005
From:	Bost D Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR # 05-0013
Download: ML050970354 (2)

Text

Exelon Generation Company, LLC f www.exeloncorp.com Exekln.

Dresden Nuclear Power Station Nuclear 6500 North Dresden Road Morris, IL 60450-9765 SVPLTR # 05-0013 March 31, 2005 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249

Subject:

Commitments and Plans Related to Extended Power Uprate Operation

Reference:

1. Letter from D. Bost (Exelon Generation Company, LLC) to U. S. NRC, N "Commitments and Plans Related to Extended Power Uprate Operation,"

dated December 10, 2004

2. Letter from D. Bost (Exelon Generation Company, LLC) to U. S. NRC, "Revised Commitments and Plans Related to Extended Power Uprate Operation," dated January 31, 2005 In Reference 1, Exelon Generation Company, LLC (EGC) made several regulatory commitments and provided the basis for continued operation of Dresden Nuclear Power Station (DNPS), Units 2 and 3, at extended power uprate (EPU) conditions in light of the steam dryer issues identified in the Fall 2004 outages. In part, EGC committed to submit an updated evaluation of the DNPS steam dryers based on additional data obtained through strain gauges installed on the main steam lines (MSLs) of each DNPS unit.

While collecting strain gauge data during the DNPS Unit 3 startup, it was determined that strain gauges at three of the eight locations did not function properly. EGC decided to perform the DNPS Unit 3 load definition with the data collected from the remaining functioning strain gauges and using instrument lines at the venturis for several MSLs. Implementation of this altemative, however, required additional time to perfomi detailed instrument line as-builts and to construct the acoustic circuit of the venturi lines, along with the load definition on the dryer. Based on this effort, EGC revised the due date for this commitment to March 2005 in Reference 2. The information is provided in the attached General Electric Nuclear Energy report.

The attached report describes the dynamic time history analyses performed on the DNPS dryers for different dryer repaired configurations. The loading used for these analyses came from plant data measurements from the MSLs. These measurements were processed using acoustical analyses to determine the pressures on the surfaces of the dryer, both interior and

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March 31, 2005 U. S. Nuclear Regulatory Commission Page 2 exterior. The report results correlate well with the unrepaired and repaired steam dryer failure behavior seen at DNPS.

In conclusion, the stresses from the plant data show good correlation with the actual inspection results for the 2003 dryer configuration. The results for the 2004 configuration predict the critical locations to be below the fatigue endurance limit for both units. The report also concludes that the 2004 steam dryer repair configuration is acceptable for EPU operation for DNPS Units 2 and 3. to this letter contains the proprietary version of the report and EGC requests that it be withheld from public disclosure in accordance with 10 CFR 2.390, "Public inspections, exemptions, requests for withholding," paragraph (a)(4). Attachment 2 contains the required affidavit.

If you have any questions concerning this submittal, please contact Mr. Pedro Salas, at (815) 416-2800.

Respectfully, Danny st Site Vice President Dresden Nuclear Power Station Attachments:

1. Exelon Steam Dryer Dynamic Time History Analyses: Dresden Unit 2 2004 Repair and Dresden Unit 3 2003 and 2004 Repair Dryer Configurations using Loads from Plant Measurements, GENE-0000-0038-6481-01 (GE Proprietary)

2. Affidavit cc: Regional Administrator - NRC Region IlIl NRC Senior Resident Inspector - Dresden Nuclear Power Station