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Event Notification Report for January 26, 2003

U.S. Nuclear Regulatory Commission
Operations Center

EVENT REPORTS FOR
01/25/2003 - 01/26/2003

EVENT NUMBERS
39537

Power Reactor
Event Number: 39537
Facility: COOK
Region: 3     State: MI
Unit: [] [2] []
RX Type: [1] W-4-LP,[2] W-4-LP
NRC Notified By: CHARLES ARCHEY
HQ OPS Officer: ARLON COSTA
Notification Date: 01/26/2003
Notification Time: 02:21 [ET]
Event Date: 01/26/2003
Event Time: 00:17 [EST]
Last Update Date: 01/26/2003
Emergency Class: NON EMERGENCY
10 CFR Section:
50.72(b)(2)(i) - PLANT S/D REQD BY TS
Person (Organization):
CHRISTINE LIPA (R3)
Power Reactor Unit Info
Unit SCRAM Code RX Crit Initial PWR Initial RX Mode Current PWR Current RX Mode
2 N Y 100 Power Operation 55 Power Operation
Event Text
PLANT SHUTDOWN REQUIRED BY TECHNICAL SPECIFICATIONS

"Cook Nuclear Plant Unit 2 Technical Specification 3.8.1.1.b requires two separate and independent diesel generators to be operable. Action b specifies [that] if one diesel is inoperable, then 'restore diesel generators to OPERABLE status within 72 hours or be in at least HOT STANDBY within the next 6 hours and in COLD SHUTDOWN within the following 30 hours.' Unit 2 diesel generator 2-OME-150-CD (Unit 2 CD diesel generator) has been inoperable since 04:00 on January 23, 2003 for scheduled maintenance. During post-maintenance testing, diesel load fluctuations occurred which continued to render the diesel inoperable. Diagnostic testing continues on the Unit 2 CD diesel generator. When it became evident operability of the Unit 2 CD diesel generator would not occur by the expiration of the 72 hour Limiting Condition of Operation at 04:00 on January 26, Cook Unit 2 began a power reduction from 100% reactor thermal power. The power reduction began at 00:17 on January 26 at a rate of approximately 20% per hour with a plan to manually trip the reactor to enter Mode 3 (Hot Standby) at 17% reactor thermal power at approximately 05:00. A cooldown to Mode 5 (Cold Shutdown) is expected within 30 hours of the entry to Mode 3 (Hot Standby) in accordance with Technical Specification 3.8.1.1, action b.

"This Four Hour Report is being made in accordance with 10 CFR 50.72(b)(2)(i) for the initiation of a nuclear plant shutdown required by a plant's Technical Specifications.

"There were no emergency plan or radiological release issues with this Unit 2 event. Unit 1 remains in Mode 5 with a main transformer replacement in progress."

The Licensee notified the NRC Resident Inspector.

* * * * UPDATE FROM CHARLES ARCHEY TAKEN BY MIKE RIPLEY AT 2310 EST ON 1/26/03 * * * *

The licensee provided the following revised wording to reflect a re-evaluation of the Technical Specification requirements for the transition to Mode 5 if the Unit 2 CD diesel generator remains inoperable:

"Cook Nuclear Plant Unit 2 Technical Specification 3.8. 1. 1 .b requires two separate and independent diesel generators to be operable. Action b specifies if one diesel is inoperable, then 'restore diesel generators to OPERABLE status within 72 hours or be in at least HOT STANDBY within the next 6 hours and in COLD SHUTDOWN within the following 30 hours.' Unit 2 diesel generator 2-OME-150-CD ('Unit 2 CD diesel generator') has been inoperable since 04:00 on January 23, 2003 for scheduled maintenance. During post-maintenance testing, diesel load fluctuations occurred which continued to render the diesel inoperable. Diagnostic testing continues on the Unit 2 CD diesel generator. When it became evident operability of the Unit 2 CD diesel generator would not occur by the expiration of the 72 hour Limiting Condition of Operation at 04:00 on January 26, Cook Unit 2 began a power reduction from 100% reactor thermal power. The power reduction began at 00:17 on January 26 at a rate of approximately 20% per hour with a plan to manually trip the reactor to enter Mode 3 (Hot Standby) at 17% reactor thermal power at approximately 05:00.

"Transition to Mode 3 is expected after the 72 hour time limit is exceeded (04:00 on January 26) and before 10:00 on January 26 (6 hours following expiration of the 72 hour time limit). Transition to Mode 5 is expected before 16:00 on January 27 (within the following 30 hours) if the Unit 2 CD diesel generator remains inoperable.

"This Four Hour Report is being made in accordance with 10 CFR 50.72(b)(2)(i) for the initiation of a nuclear plant shutdown required by a plant's Technical Specifications.

"There were no emergency plan or radiological release issues with this Unit 2 event. Unit 1 remains in Mode 5 (Cold Shutdown) with a main transformer replacement in progress." R3DO (Christine Lipa) notified.

The NRC Resident Inspector was notified of this update by the licensee.