ML092080506

PNO-I-09-004A: Updated - Millstone Unit 2 Reactor Trip and Shutdown Greater than 72 Hours

ML092080506
Person / Time
Site:	Millstone
Issue date:	07/27/2009
From:	Barber G S NRC/RGN-I/DRP/PB6
To:
bellamy RR
References
PNO-I-09-004A, FOIA/PA-2011-0115
Download: ML092080506 (1)

Text

DCS No.: 0500033607272009 Date: July 27, 2009

PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-09-004A

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 Millstone Unit 2 Waterford, CT Docket: 50-336 Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable

SUBJECT:

UPDATED - MILLSTONE UNIT 2 REACTOR TRIP AND SHUTDOWN GREATER THAN 72 HOURS

This preliminary notification updates information in PNO-I-09-004, which documents a July 3 reactor trip of Millstone Unit 2 initiated by a loss of an offsite line, resulting in an inadvertent closure of the main turbine stop valves. At the time of the last notification, the plant had achieved cold shutdown to effect repairs to a degraded "A" reactor coolant pump (RCP) seal that was unrelated to the reactor trip.

During the forced outage, the "A" RCP seal package was replaced. During the subsequent heatup, licensee and NRC inspectors observed additional leakage from the seal cooler area. The licensee determined that the leak was from an exposed elbow on a seal cooler line before it entered the thermal barrier heat exchanger. This leak constituted reactor coolant pressure boundary leakage. The leak was determined to be through a weld that was subsequently repaired and retested satisfactorily. Because the forced outage work affected secondary containment, an emergency building filtration system (EBFS) draw down test had to be performed. This test initially failed to draw down the required amount of vacuum in the secondary containment building. Repairs were completed on the EBFS by July 23, which was followed by a successful vacuum test of the building.

On July 25, the licensee took the reactor critical at 8:54 a.m., placed the turbine in service and connected the plant to the electrical grid at 5:27 p.m. Millstone achieved 100% power on July

26. The Resident Inspectors observed portions of the plant startup and continue to follow the licensee's corrective maintenance activities.

State and local officials have been informed. The NRC Region I Public Affairs Office is responding to media inquiries.

The information presented herein has been discussed with Dominion and is current as of July 27, 2009 at 2:00 p.m.

ADAMS Accession Number: ML092080506

CONTACT: Scott Barber (610) 337-5232

2DISTRIBUTION: (PN Recipient List)

Chairman Jazcko Comm. Klein Comm. Svinicki OIP OCA OGC OPA EDO OE NRR SECY IRO NMSS ACRS OIG RES NSIR NRO PDR RSLO Regional Offices

By Fax:

DOT:Trans INPO NSAC RI Resident Office Licensee: Dominion Nuclear Connecticut (Millstone 2)

ADAMS ML092080506 SUNSI Review Complete: SB ___ (Reviewer's Initials)

DOCUMENT NAME: G:\DRP\PNS\PNO-I-09-004A - MP2 RX TRIP.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/PAO RI/DRP RI/DRP NAME SBarber/SB DTifft/ DBT DScrenci/NS for DLew/ JWC for RBellamy/RRB DATE 07/27/09 07/27/09 07/27/09 07/27/09 7/27/09 OFFICIAL RECORD COPY