ML080980197
| ML080980197 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/07/2008 |
| From: | Norris B NRC Region 1 |
| To: | |
| Norris B, RGN-1/DRP/Br6 610-337-5111 | |
| References | |
| PNO-I-08-004 | |
| Download: ML080980197 (3) | |
Text
Date: April 7, 2008 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-I-08-004 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, King of Prussia, PA, staff on this date.
Facility License Emergency Classification Dominion Resources
__ X __Notification of Unusual Event Millstone Power Station, Unit 2
_____Alert Niantic, CT 06357
_____Site Area Emergency Docket: 050-336
_____General Emergency License: DPR-65
__ ___Not Applicable
SUBJECT:
NOTIFICATION OF UNUSUAL EVENT DUE TO INCREASE IN UNIDENTIFIED LEAKAGE FOLLOWING SHUTDOWN FOR A REFUELING OUTAGE DESCRIPTION:
On April 6, 2008, at 1:17 p.m., Millstone Unit 2 declared an Unusual Event due to an unexpected increase in reactor coolant system (RCS) unidentified leakage rate. At the time, Millstone Unit 2 was shut down for a scheduled refueling outage and proceeding to the shutdown cooling mode of operation. At 12:36 p.m., on April 6, the RCS unidentified leakrate increased concurrent with an unexpected increase in refueling water storage tank (RWST) level.
Region I entered the Monitoring Mode at 2:30 p.m. Resident inspectors reported to the site to monitor the event. At 1:56 p.m., the unidentified leak rate returned to normal, following licensee actions to identify and close valves in the leakage path from the RCS to the RWST.
While no radioactive liquids were released from the site, some low-level radioactive gas was likely released through the RWST vent. The NRC independently evaluated the potential release and radiological consequence. Preliminary estimates indicate that any release was well below regulatory limits for normal operations.
Millstone Unit 3, another reactor operated by Dominion, was not affected by the event and continues to operate at 100-percent power.
The Unusual Event was terminated at 6:56 p.m., after verification that the RCS leak was stopped. The plant is in the process of cooling down. Region I exited the Monitoring Mode at 7:20 p.m. The NRC will continue to follow the licensees activities and the conditions that lead to the event.
Federal and state officials have been notified of the event. NRC Region I Public Affairs is prepared to respond to media inquires. This notification was reviewed with the
Operations Manager on-call, at 8:15 p.m. on April 6, and represents available information as of that time.
It is not expected that this PN will be updated.
ADAMS Accession Number: ML080980197 CONTACT: Barry Norris (610) 337-5111 BSN@nrc.gov
DISTRIBUTION: (PN Recipient List)
OWFN TWFN Chairman Klein Comm. Lyons NMSS Comm. Jaczko ACRS Comm. Svinicki OIP NSIR OCA OIG OGC EDO OE NRR SECY Regional Offices BY FAX:
Dot: Trans INPO NSAC RI Resident Office Licensee: Dominion Resources Millstone Power Plant ML080980197 SUNSI Review Complete: BSN (Reviewers Initials)
DOCUMENT NAME: T:\\DRP\\PNs\\PN108004.doc 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 OFFICE RI/DRP RI/ORA RI/ORA RI/ORA RI/DRP NAME BNorris/BSN RBarkley/RSB NMcNamera/NTM DScrenci/DPS DLew/DCL DATE 04/07/08 04/07/08 04/07/08 04/07/08 04/07/08 OFFICIAL RECORD COPY