ML060170755
| ML060170755 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 01/17/2006 |
| From: | Ring M A, Stoedter K K Division Reactor Projects III |
| To: | |
| References | |
| PNO-III-06-001 | |
| Download: ML060170755 (2) | |
Text
January 17, 2006PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-III-06-001This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or publicinterest 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.FacilityExelon Generation Co.Quad Cities Nuclear Power Station Docket: 50-254 and 50-265License: DPR-29 and DPR-30Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable
SUBJECT:
DEGRADED ACTUATORS FOR ELECTROMAGNETIC RELIEF VALVES DESCRIPTION:Quad Cities Unit 2 was shut down on December 30, 2005, following the discovery of degradationof the electromatic relief valve (ERV) actuators. Unit 1 was lowered to 85 percent power onDecember 31, 2005, following the discovery on Unit 2. On January 6, 2006, the licensee shutdown Unit 1 to inspect the ERV actuators. The NRC initiated a Special Inspection Team (SIT) on January 9, 2006, to review thecircumstances surrounding the degradation and to follow the licensee's root cause effor ts. The electromatic relief valves, four on each unit, are used for automatic depressurization and tomitigate an Anticipated Transient Without Scram event. All four valves on both units showedsome degradation. The 3D valve on Unit 2 and the 3D valve on Unit 1 did not stroke properlywhen tested and two other valves on Unit 1 (3B & 3C) may not have worked properly. The initial cause was thought to be flow induced vibration from higher power levels authorized in an extended power uprate. The actuators for all four valves on both units were replaced, and bothunits were returned to previous full power level (85 percent of the extended power uprate level)on January 8, 2006, for Unit 1 and January 3, 2006, for Unit 2.The licensee shut down Unit 2 on January 13, 2006, because of additional concerns with pivotpoints internal to the actuators and welds on the turnbuckles connecting the actuators to themain valves. While the pivot points were found to be in satisfactory condition, one of the Unit 2 valves failed to function properly during testing. As a result, Unit 1 was shut down on January 15, 2006, to inspect and test the ERVs. All four Unit 1 valves were successfully tested.Both units remain shut down as the licensee continues its root cause investigation andrefurbishment activities for the ERV actuators. The NRC special inspection team is onsite to monitor the licensee's activities.The States of Illinois and Iowa will be informed. Region III (Chicago) issued a news release onthe special inspection on January 10, 2006, and continues to respond to news media inquiries.
The information in this preliminary notification has been reviewed with licensee management.This information is current as of 2 p.m. CST on January 17, 2006.
CONTACTS:Mark RingKarla Stoedter630-829-9703309-654-2227