PNO-III-11-003, Palisades Shutdown Due to Loss of Main Generator Electrical Load

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PNO-III-11-003, Palisades Shutdown Due to Loss of Main Generator Electrical Load
ML110240643
Person / Time
Site: Palisades Entergy icon.png
Issue date: 01/24/2011
From: John Ellegood, Jack Giessner
Division of Nuclear Materials Safety III
To:
Entergy Nuclear Operations
References
PNO-III-11-003
Download: ML110240643 (2)


PRELIMINARY NOTIFICATION- REGION III January 24, 2011 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-III-11-003 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.

Facility Licensee Emergency Classification Palisades Nuclear Plant Notification of Unusual Event Entergy Nuclear Operations, Inc. Alert Covert, MI Site Area Emergency Docket: 50-255 General Emergency License: DPR-20 X Not Applicable

SUBJECT:

PALISADES SHUTDOWN DUE TO LOSS OF MAIN GENERATOR ELECTRICAL LOAD DESCRIPTION:

At 5:35 p.m. (EST) on January 22, 2011, the Palisades reactor tripped (shut down automatically). An electrical fault caused the main generator to isolate, followed by a turbine trip. Consequently, the reactor shut down in accordance with the plant design to ensure the reactor was in a stable condition.

All safety systems functioned as designed and plant safety was not compromised.

During plant shutdown, a valve that normally allows the steam that comes from the steam generators to be sent into the condenser did not open. When this valve failed to admit steam to the condenser, another system - the atmospheric dump valve system - fulfilled its function and relieved steam to the atmosphere. This steam is from the non-nuclear part of the plant and is not associated with reactor coolant. The steam contains very low levels of tritium which are well within the regulatory limits for activity release from the site. The site discovered a blown fuse which caused the condenser steam valve and two out of the four atmospheric dump valves not to open. The fuse has been replaced and NRC inspectors will follow-up on these matters.

There was no impact to the environment or the health and safety of the public.

The licensee identified the source of the electrical problem as a damaged cable. The licensee is using an alternate power supply for the busses associated with the damaged cable.

NRC Resident Inspectors responded to the site and are continuing to monitor the licensees evaluation of what caused the electrical fault, repairs that are necessary for the plant to startup, and startup activities.

The State of Michigan has been informed by telephone.

Region III received initial notification of this occurrence by telephone notification to the Resident Inspectors from the licensee on January 22, 2011. The information in this preliminary notification has been reviewed with licensee management and is current as of 12:00 p.m. (EST) on January 24, 2011.

ADAMS Accession Number ML110240643 CONTACTS: John Ellegood John Giessner 269/764-8971 630/829-9619 2