ML070520400
| ML070520400 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 02/09/2007 |
| From: | Jensen J Indiana Michigan Power Co |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| AEP:NRC-7504 | |
| Download: ML070520400 (3) | |
Text
Indiana Michigan Power INDIANA Cook Nuclear Plant MICHIGAN One Cook Place POWE Bridgman, MI 49106 AEP~corn A unit of Amencan Electric Power February 9, 2007 AEP:NRC:7504 10 CFR 50.4 Docket Nos.: 50-315 50-316 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Stop O-Pl-17 Washington, DC 20555-0001 Donald C. Cook Nuclear Plant Units 1 and 2 Hydrogen Igniter Backup Power Supply This letter is to notify the Nuclear Regulatory Commission (NRC) of changes that Indiana Michigan Power Company (I&M) intends to implement at the Donald C. Cook Nuclear Plant (CNP) that will enhance plant capabilities to mitigate the potential for early containment failure from hydrogen combustion following a severe accident. These changes were discussed with the NRC staff during a January 17, 2007, meeting with representatives from plants that are affected.by hydrogen combustion following a severe accident.
The changes address and resolve concerns related to GSI-189, "Susceptibility of Ice Condenser and Mark III Containments to Early Failure from Hydrogen Combustion During a Severe Accident."
CNP has existing tandem diesel generator sets, referred to as Supplemental Diesel Generators, with a combined capacity of 4.5 megawatts. These generators can be connected to the auxiliary power system, including the hydrogen igniters, in either CNP unit. Approved procedures are currently in place to connect the generators as necessary to mitigate events resulting in a loss of the other available sources of alternating current power.
I&M has voluntarily implemented these design features and equipment and they are currently available as a backup source of electrical power to the hydrogen igniters.
Currently, the igniters can only be activated by using control switches located in the control room complex. I&M intends to install a design modification in both Unit I and Unit 2 that provides an alternative method of activating the hydrogen igniters from an area other than the control room complex. The current design does not provide an efficient means to initiate hydrogen ignition for scenarios that involve control room evacuation or for which the control room is otherwise unavailable. It is I&M's opinion that the proposed control diversity will enhance the availability of the hydrogen ignition system and resolve GSI-189 issues.
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U. S. Nuclear Regulatory Commission Page 2 AEP:NRC:7504 I&M's commitment to install an alternative method of activating the hydrogen igniters is provided in the attachment to this letter. Should you have any questions, please contact Ms. Susan D. Simpson, Regulatory Affairs Manager, at (269) 466-2428.
Sincerely,
-Joseph N. Jensen Site Vice President RV/rdw c: J. L. Caldwell, NRC Region III K. D. Curry, Ft. Wayne AEP J. T. King, MPSC MDEQ - WHMD/RPMWS NRC Resident Inspector P. S. Tam, NRC. Washington, DC
Attachment to AEP:NRC:7504 Regulatory Commitment The following table identifies the action committed to by Indiana Michigan Power Company (I&M) in this document. Any other actions discussed in this submittal represent intended or planned actions by I&M.
They are described to the Nuclear Regulatory Commission (NRC) for the NRC's information and are not regulatory commitments.
Commitment Date I&M will install design modifications in both Unit I and Unit 2 that provide an alternative method of activating the hydrogen December 31, 2007 igniters from an area other than the control room complex.