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.: 0500033640106 Date: April 3, 2006 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-06-005 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 I staff on this date.
Facility Millstone Unit 2 Power Station Licensee Emergency Classification Waterford, CT Notification of Unusual Event Docket: 05000336 Alert Site Area Emergency General Emergency X Not Applicable
SUBJECT:
SHUTDOWN GREATER THAN 72 HOURS - MILLSTONE UNIT 2 TURBINE DRIVEN AUXILIARY FEEDWATER PUMP ROTATING ASSEMBLY DEGRADATION On April 1, 2006, at 7:55 a.m., Millstone Unit 2 removed the turbine generator from operation in conjunction 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 outboard pump 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 engineering personnel have evaluated the shaft condition and consider it acceptable for continued use.
During further disassembly activities on March 31, maintenance personnel observed an additional problem with a balancing drum assembly that supports TDAFP operation. This condition, 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 11:00 a.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 March 29 and did observe portions of the Unit 2 shutdown and cooldown. The facts of this PN were verified with S. Scace, Nuclear Safety and Licensing Director.
The Region I Public Affairs Office is prepared to respond to media inquiries. The states of Connecticut and New York have been informed.
ADAMS Accession Number: ML060930424 CONTACT: Paul Krohn (610) 337-5120
DISTRIBUTION: (PN Recipient List)
OWFN TWFN LST Chairman Diaz Comm. Lyons NMSS Comm. Jazcko ACRS Comm. McGaffigan Jr. OIG Comm. Merrifield RES OIP NSIR OCA OGC OPA EDO OE NRR SECY Regional Offices By Fax:
DOT:Trans INPO NSAC RI Resident Office Licensee: Dominion ADAMS Accession Number: ML060934424 SISP Review Complete: PGK (Reviewers Initials)
DOCUMENT NAME: E:\Filenet\ML060930424.wpd After 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 without attachment/enclosure "E" = Copy with attachment/enclosure "N" = No copy OFFIC RI/DRP RI/DRP RI/ORA RI/DRP RI/DR E P NAME SBarber RBores DScrenci PKrohn BHolian/GS B
DATE 04/03/06 04/03/06 04/03/06 04/03/06 0403/06 OFFICIAL RECORD COPY Region I Form 83 (Rev. July 2, 2003)