SVPLTR 05-0005, Revised Commitments and Plans Related to Extended Power Uprate Operation

Revised Commitments and Plans Related to Extended Power Uprate Operation

ML050400204
Person / Time
Site:	Dresden
Issue date:	01/31/2005
From:	Bost D Exelon Generation Co, Exelon Nuclear
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
SVPLTR # 05-0005
Download: ML050400204 (3)

Text

Exelkn.

Exelon Generation Company, LLC www.exeloncorp.com Dresden Nuclear Power Station Nuclear 6500 North Dresden Road Morris. IL 60450-9765 SVPLTR # 05-0005 January 31, 2005 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:

Revised Commitments and Plans Related to Extended Power Uprate Operation

Reference:

Letter from D. Bost (Exelon Generation Company, LLC) to U. S. NRC, "Commitments and Plans Related to Extended Power Uprate Operation," dated December 10, 2004 In the referenced letter, 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. After troubleshooting the data collection system, it was determined that the problem existed in the portion of the system located inside the drywell, and that repairs cannot be completed with the unit online.

As a result of the unavailability of some of the strain gauge data, EGC has explored technical alternatives to develop the dryer loading from Unit 3. EGC has determined that a reasonable approach would be to perform the DNPS Unit 3 load definition with data collected from the remaining functioning strain gauges and using instrument lines at the venturis for several MSLs.

Implementation of this alternative, however, requires additional time to perform 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, it is anticipated that the load definition and stress analysis for DNPS Unit 3 will not be completed until the end of March 2005. Therefore, EGC is revising the completion date for submitting an updated evaluation of the DNPS steam dryers for EPU operation to March 2005. This also delays our planned meeting with the N

January 31, 2005 U. S. Nuclear Regulatory Commission Page 2 to discuss the updated evaluation to late May 2005. These changes were discussed with the NRC during the January 25 and 26, 2005, meeting with EGC related to steam dryer loading.

The attachment to this letter provides revised regulatory commitments that EGC is making related to EPU operation for DNPS Units 2 and 3 due to the non-functioning strain gauges on DNPS Unit 3.

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

Respectfully, Danny Bost Site Vice President Dresden Nuclear Power Station

Attachment:

Summary of Commitments cc: Regional Administrator- NRC Region IlIl NRC Senior Resident Inspector - Dresden Nuclear Power Station

ATTACHMENT Summary of Commitments The following table identifies commitments being made by Exelon Generation Company, LLC (EGC). Any other actions discussed in this letter represent intended or planned actions by EGC. They are described for the NRC's information and are not regulatory commitments.

Committed Date Commitment or Outage 1 For each DNPS unit, EGC will use the data collected from the main March 2005 steam line strain gauges in the acoustic circuit analysis to better define the loads'at extended power uprate (EPU) power. A dynamic finite element model (FEM) will then be completed for the as-modified steam dryers. The acoustic circuit analysis time histories will be put into the FEM to demonstrate the robustness of the 2004 repairs and modifications compared to the 2003 repairs and modifications. EGC will submit an updated evaluation of the DNPS steam dryers for EPU operation.

2 EGC will meet with the NRC to share the results of the detailed Late May 2005 acoustic circuit analyses described above.

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