PNO-III-03-026, Quad Cities, Cracks Discovered in the Unit 2 Steam Dryer
| ML031640650 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 06/13/2003 |
| From: | Ring M, Ross Telson NRC/RGN-III |
| To: | |
| References | |
| PNO-III-03-026 | |
| Download: ML031640650 (2) | |
June 13, 2003 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-III-03-026 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 Quad Cities Nuclear Power Station Exelon Nuclear Cordova, IL Docket: 50-265 License: DPR-30 Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency x Not Applicable
SUBJECT:
CRACKS DISCOVERED IN THE UNIT 2 STEAM DRYER DESCRIPTION:
On June 12, 2003, the licensee discovered cracks in the upper dryer outer hood cover plate of the steam dryer of Unit 2 at the Quad Cities Nuclear Power Station while the unit was shut down to evaluate elevated moisture carryover to the main steam lines and turbine.
First indications of elevated moisture carryover on Unit 2 were noted on June 7, 2002, after the units return to service following an extended power uprate in March. The unit was subsequently shut down and cracking problems were found on the lower cover plate. Those problems were repaired and the unit was later returned to service in July 2002. Further information regarding this event is discussed in NRC Information Notice 2002-06.
On April 16, 2003, Unit 2 was shut down because a power operated relief valve unexpectedly opened and failed to close. Shortly after the unit returned to service upon completion of repairs, operators again noted elevated moisture carryover. As a result, Unit 2 was shut down for troubleshooting and repairs on June 11.
The upper dryer outer hood cover plate is a 1/2 inch thick plate welded in place with internal bracing. The plate has cracks in the base metal of the plate and the longest crack is approximately 9 and 1/2 feet in total length. The licensee is investigating the cause of the steam dryer damage and making repair plans.
To date, no problems have been identified with the Unit 1 steam dryer.
The NRC resident inspectors are monitoring the licensees assessment and repair plans and an NRC metallurgical specialist inspector is expected to arrive on site Monday to assist.
The information in this preliminary notification has been reviewed with utility management.
This information is current as of 3 p.m. (CDT) on June 13, 2003.
CONTACTS:
Mark Ring Ross Telson 630/829-9703 309/654-2227