ML101760522

From kanterella
Jump to navigation Jump to search
PNO-III-10-010 - Palisades - Forced Shutdown for Greater than 72 Hours to Replace Leaking Control Rod Drive Seal
ML101760522
Person / Time
Site: Palisades Entergy icon.png
Issue date: 06/25/2010
From: John Ellegood, Giessner J A
NRC/RGN-III
To:
References
PNO-III-10-010
Download: ML101760522 (2)


Text

PRELIMINARY NOTIFICATION- REGION III June 25, 2010 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-III-10-010

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

SUBJECT:

PALISADES FORCED SHUTDOWN FOR GREATER THAN 72 HOURS TO REPLACE LEAKING CONTROL ROD DRIVE SEAL DESCRIPTION:

On June 24, 2010, the licensee shut the plant down using normal shutdown procedures due to a leaking Control Rod Drive (CRD) seal.

The licensee noted a rapid rate increase on the leak rate for control rod 22 which was indicative of a CRD seal failing. The elevated leakage rate and upward trend prompted the licensee to shut down the plant in order to repair the leaking seal.

While limited CRD seal leakage is not unusual for the CRD seal design at Palisades, elevated CRD seal leakage rates and increasing leak-rate trends are indicators of CRD seal degradation. The site has experienced elevated CRD seal leakage rates and increasing leak-rate trends in the past which required similar plant shutdowns.

CRD leakage is routed to the containment sump where it is collected and processed. The leakage creates no unmonitored offsite dose impact nor did the CRD leakage impact safety system performance.

The duration of the shutdown is expected to exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

The State of Michigan has been informed.

NRC inspectors will continue to monitor the shutdown, repair, and restart activities.

Region III received initial notification of this occurrence by telephone notification to the resident inspectors from the licensee on June 23, 2010. The information in this preliminary notification has been reviewed with licensee management and is current as of 12:10 p.m. (CDT) on June 25, 2010.

2 ADAMS Accession Number ML101760522.

CONTACTS: John Ellegood John Giessner 269/764-8971 630/829-9619