PNO-I-06-005, Millstone Unit 2, Shutdown Greater than 72 Hours - Turbine Driven Auxiliary Feedwater Pump Rotating Assembly Degradation
| ML060930424 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/03/2006 |
| From: | NRC Region 1 |
| To: | |
| References | |
| PNO-I-06-005 | |
| Download: ML060930424 (2) | |
DCS No.: 0500033640106Date: April 3, 2006PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-06-005This 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 I staff on this date.FacilityMillstone Unit 2 Power Station Waterford, CT Docket: 05000336Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable
SUBJECT:
SHUTDOWN GREATER THAN 72 HOURS - MILLSTONE UNIT 2 TURBINEDRIVEN AUXILIARY FEEDWATER PUMP ROTATING ASSEMBLY DEGRADATIONOn April 1, 2006, at 7:55 a.m., Millstone Unit 2 removed the turbine generator from operation inconjunction with a shutdown required by Technical Specifications (TS) 3.7.1.2 due to an inoperable turbine-driven auxiliary feedwater pump (TDAFP). Previously, on March 29, during a planned retest following governor maintenance, the outboardpump bearing of the TDAFP exhibited signs of overheating and high vibrations. An event review team (ERT) was formed to identify root causes and to propose corrective actions while, in parallel, licensee maintenance personnel began to develop a troubleshooting and repair plan. Subsequently, the licensee found the bearing needed replacement. Licensee engineeringpersonnel have evaluated the shaft condition and consider it acceptable for continued use. During further disassembly activities on March 31, maintenance personnel observed anadditional problem with a balancing drum assembly that supports TDAFP operation. Thiscondition, in combination with the degraded bearing, precluded restoring the TDAFP to an operable status prior to the expiration of the TS-allowed outage time at 3:55 a.m., April 1, 2006. Thus, a shutdown to comply with TS was begun at 10:20 p.m., March 31, 2006. As of 11:00a.m., April 3, 2006, troubleshooting and repair activities are continuing with the plant in Mode 4. The NRC resident inspector staff have been following TDAFP recovery activities since March29 and did observe portions of the Unit 2 shutdown and cooldown. The facts of this PN wereverified with S. Scace, Nuclear Safety and Licensing Director. The Region I Public Affairs Office is prepared to respond to media inquiries. The states ofConnecticut and New York have been informed.ADAMS Accession Number: ML060930424CONTACT:Paul Krohn (610) 337-5120 DISTRIBUTION: (PN Recipient List
)OWFN TWFNLSTChairmanDiaz Comm. Lyons NMSS Comm. JazckoACRS Comm. McGaffigan Jr.OIGComm. MerrifieldRESOIPNSIR OCA OGCOPAEDO OE NRRSECYRegional OfficesBy Fax:DOT:TransINPO NSAC RI Resident Office Licensee:DominionADAMS Accession Number: ML060934424SISP Review Complete: PGK (Reviewer's Initials)DOCUMENT NAME: E:\Filenet\ML060930424.wpdAfter declaring this document "An Official Agency Record" it will be released to the Public.To receive a copy of this document, indicate in the box:
" C" = Copy withoutattachment/enclosure " E" = Copy with attachment/enclosure " N" = No copy OFFIC E RI/DRP RI/DRP RI/ORA RI/DRP RI/DR P NAMESBarber RBoresDScrenci PKrohnBHolian/GS BDATE04/03/0604/03/0604/03/0604/03/060403/06 OFFICIAL RECORD COPYRegion I Form 83 (Rev. July 2, 2003)