ML081480507
| ML081480507 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 05/27/2008 |
| From: | Racquel Powell Division of Nuclear Materials Safety I |
| To: | |
| Powell R, RI/DRP/610-337-6967 | |
| References | |
| PNO-I-08-007 | |
| Download: ML081480507 (3) | |
Text
DCS No.: 0500042305272008 Date: 05/27/2008 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-I-08-007 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 Dominion Nuclear Connecticut, Inc.
Millstone Nuclear Power Station Unit 2 Waterford, CT Docket: 50-336 Licensee Emergency Classification X Notification of Unusual Event Alert Site Area Emergency General Emergency Not Applicable Docket No.: 50-336 License No.: NPF-49
SUBJECT:
UNUSUAL EVENT DECLARED DUE TO LOSS OF OFFSITE POWER AT MILLSTONE UNIT 2 On May 24, 2008, at 9:38 a.m., Millstone Unit 2 experienced a loss of all offsite power (LOOP).
At 9:54 a.m., Dominion Nuclear Connecticut, Inc. declared an Unusual Event at Millstone Unit 2 due to the LOOP for greater than 15 minutes. Dominion determined that the LOOP was due to a loss of the Reserve Station Service Transformer (RSST). Both emergency diesel generators (EDGs) started as designed and re-energized the electrical safety buses. At 11:06 a.m.,
electrical power was restored to one safety-related bus using the cross-tie from Unit 3, and the A EDG was secured. On May 25, at 12:52 p.m., Dominion exited the Unusual Event after establishing the reliability of the cross-tie, restoration of the RSST, and energization of the non-safety busses. Millstone Unit 3 was unaffected by this event.
The NRC Resident Inspectors were on-site and responded to the Unit 2 Main Control Room when the event occurred. NRC Region I entered the Monitoring Mode and staffed its Incident Response Center to follow the licensees actions and evaluate plant safety performance. The NRC exited the Monitoring Mode at 1:04 p.m., on May 25, after verifying the licensees actions to exit the Unusual Event. The NRC will continue to evaluate the event through the agencys event followup process, including dispatching electrical inspectors to review the licensees root cause evaluation. The electrical inspectors will also evaluate the licensees conclusion that this event was unrelated to the previously reported reactor trip on May 22. The NRC Region I Public Affairs Office has issued a press release and has responded to media inquiries. The NRC notified the State of Connecticut and the State of New York. The licensee did not issue a press release for this event.
Region I received initial notification of this occurrence by telephone call from the Resident Inspector staff at approximately 10:00 a.m. The information presented herein has been discussed with Dominion and is current as of May 27, at 3:00 p.m.
This preliminary notification is issued for information only, and no further preliminary notification update by the staff is anticipated.
ADAMS Accession Number ML081480507
Contact:
Raymond Powell, 610-337-6967
DISTRIBUTIONS:
BY E-MAIL:
Chairman Klein Comm. McGaffigan Jr.
Comm. Jaczko Comm. Lyons Comm. Svinicki OIP OCA OGC EDO OE NRR NMSS OIG RES ACRS FSME NRO NSIR OPA SECY Regional Offices BY FAX:
DOT:Trans INPO NSAC RI Resident Office Licensee:
Dominion Nuclear Connecticut, Inc.,
Millstone Power Station Region I Form 83 (Rev. Nov. 21, 2006)
SUNSI Review Complete: RJP (Reviewer=s Initials)
DOCUMENT NAME:S:\\PN\\pn108007.doc After declaring this document AAn 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 OFFICE RI/DRP RI/PAO RI/SLO RI/DRP NAME RPowell/RJP DScrenci/DPS NMcNamera/NTM JClifford/JWC DATE 05/27/08 05/27/08 05/27/08 05/27/08 OFFICIAL RECORD COPY