ML032050453
| ML032050453 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 07/17/2003 |
| From: | Hovey R Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| RHLTR: #03-0046, USI A-46 | |
| Download: ML032050453 (2) | |
Text
Exelenm Exelon Generation www exeloncorp.com Nuclear Dresden Generating Station 6500 North Dresden Road Morris, IL 60450-9765 Tel 815-942-2920 July 17, 2003 RHLTR: #03-0046 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Facility Operating License Nos. DPR-19 and DPR-25 Docket Nos. 50-237 and 50-249
Subject:
Delay in Completion of Unresolved Safety Issue (USI) A-46 Commitment
References:
(1)
Letter from J. M. Heffley (Commonwealth Edison Company)) to U. S.
NRC, "Response to Request for Additional Information Regarding Unresolved Safety Issue (USI) A-46," dated May 18, 1999 (2)
Letter from L. W. Rossbach (USNRC) to 0. D. Kingsley (EGC), Dresden Plant-Specific Safety Evaluation for USI A-46 Program Implementation,"
dated February 23, 2000 In Reference 1, Commonwealth Edison Company, now Exelon Generation Company, LLC (EGC), committed to complete actions related to USI A-46, "Seismic Qualification of Equipment in Operating Plants," for Dresden Nuclear Power Station (DNPS), Units 2 and 3, within two refueling outages per unit following receipt of the NRC safety evaluation. In Reference 2, the NRC accepted this implementation schedule. Based on this schedule, actions to complete resolution of these items for DNPS, Unit 3 were to be completed by October 2002 (i.e., during the completion of the second Unit 3 refueling outage following receipt of Reference 2). The purpose of this letter is to notify the NRC of a delay in completing DNPS, Unit 3 modifications for five 250 volt direct current (VDC) motor control centers (MCCs), which require a refueling outage for installation. That work will be completed during the next Unit 3 refueling outage D3R18, scheduled for fall 2004.
Relays in the 250 VDC MCCs at DNPS were determined to be USI A-46 outliers, since the seismic demand exceeds the seismic capacity for these components. Due to a number of factors, DNPS chose to install new MCC cubicles to resolve these outliers. This work requires a refueling outage. The DNPS Unit 3 cubicles were scheduled for replacement in October 2002 (D3R17). The majority of 250 VDC cubicles were replaced during D3Rl7 in accordance with
.4 W the original NRC commitment except for five cubicles. For these five cubicles, our pre-installation review of the vendor-submitted drawings determined that the new MCCs were not an equivalent replacement and different components were needed. The vendor could not modify the MCC cubicles in time to support installation during D3R17. As a result, Unit 3 MCC cubicles B01, C01, C02, D01, and D02 replacements will be completed in D3R18, currently scheduled for fall 2004.
Additionally, there are six work orders that remain open associated with DNPS Unit 3 outliers.
These items are 250 VDC MCC bracing, pumpback line modification, component cooling service water heat exchanger tie in, cardox relay replacement, diesel generator relay replacement, and auto blowdown relay replacement. These additional items are scheduled to be completed by the end of the upcoming Unit 2 refueling outage scheduled for October 2003.
These work orders were inappropriately scheduled for the end of the second DNPS Unit 2 refueling outage due to a misunderstanding of the original commitment. It was understood that all outage related work was to be completed by the end of the second respective unit outage and that all non-outage related work for both Units 2 and 3 could be completed by the end of the second DNPS Unit 2 outage. Subsequent review determined that this understanding was incorrect.
All the remaining Unit 2 USI A-46 outlier resolution work was reviewed and will be completed within the commitment dates (i.e. end of the Unit 2 refueling outage scheduled for October 2003).
Should you have any questions concerning this letter, please contact Mr. Jeff Hansen, Regulatory Assurance Manager, at (815) 416 - 2800.
Respectfully, R. J. Hovey Site Vice President Dresden Nuclear Power Station cc:
Regional Administrator - NRC Region IlIl NRC Senior Resident Inspector - Dresden Nuclear Power Station