PNO-I-07-006, Reactor Scram on Low Reactor Vessel Water Level Due to a Trip of the C Reactor Feed Pump
| ML071990428 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 07/17/2007 |
| From: | Barber G Division Reactor Projects I |
| To: | |
| Barber G S, RGN-I/DRP/610-337-5232 | |
| References | |
| 05000219071707 PNO-I-07-006 | |
| Download: ML071990428 (3) | |
DCS No.: 05000219071707 Date: July 17, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-I-07-006 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 Amergen Energy Company, LLC Oyster Creek Forked River, NJ Docket: 50-219 Licensee Emergency Classification Notification of Unusual Event Alert Site Area Emergency General Emergency X Not Applicable
SUBJECT:
REACTOR SCRAM ON LOW REACTOR VESSEL WATER LEVEL DUE TO A TRIP OF THE 'C' REACTOR FEED PUMP On July 17, 2007, at 5:22 a.m., the Oyster Creek reactor scrammed due to a low reactor water level following a trip of the 'C' Reactor Feed Pump (RFP). Reactor water level reached the low-low level setpoint which, among other actions, automatically isolated the main steam isolation valves and initiated the isolation condensers. The isolation condensers steam off plant condensate to remove decay heat. Although there was no abnormal amount of radioactivity released during the event, a small amount of activity was released by steaming off condensate that contained trace amounts of radioactive tritium. The preliminary estimates of the activity released was about 1.05 curies which resulted in a worst case offsite dose of about 0.005 millirem which is about 3000 times less than the annual organ limit of 15 millirem and 25 millirem total body.
Immediately prior the scram, reactor water level had decreased due to a steam flow/feed flow mismatch. After the scram, water level increased due to excessive feeding causing a high reactor water level which necessitated cycling two Electromagnetic Relief Valves (EMRVs).
The steam relief from the EMRVs caused an increase in the torus temperature that was controlled by using the Containment Spray System in torus cooling mode. No emergency action level was declared as a result of this event. The reactor was placed in a cold shutdown condition at 2:00 p.m., July 17, 2007.
Preliminary information indicates that the 'C' RFP tripped due to an electrical fault. Planned licensee actions include a review to determine the cause of the 'C' RFP trip, repairs to the 'C' RFP, and a review of plant and operator response during the event.
The NRC resident inspector responded to the site and has been supported by regional inspectors during the NRC's initial assessment of this event. The NRC is continuing to assess the licensee's response to this event. The facts of this Preliminary Notification were verified with the Oyster Creek Plant Manager and were current as of 4:00 p.m., July 17, 2007.
2 AmerGen has issued an event notification (EN#43495) in accordance to 10 CFR 50.72 and has issued press releases. The state of New Jersey has been notified.
This PN will be updated as close to plant restart as possible.
ADAMS Accession Number: ML071990428 CONTACT:
G. Scott Barber (610) 337-5232
3 DISTRIBUTIONS:
BY E-MAIL:
OWFN TWFN Chairman Klein Comm. McGaffigan Jr.
NMSS Comm. Jaczko OIG Comm. Lyons RES OIP OCA OGC EDO OE NRR SECY Regional Offices BY FAX:
DOT:Trans INPO NSAC RI Resident Office Licensee: AmerGen Energy Company, LLC Oyster Creek Nuclear Generating Station ADAMS ML071990428 SUNSI Review Complete: GSB (Reviewers Initials)
DOCUMENT NAME: T:\\DRP\\PNs\\PNO-I-07-006 Oyster Creek scram due to a loss of C RFP Rev 2.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 OFFICE RI/DRP RI/ORA RI/ORA RI/DRP NAME SBarber/GSB DScrenci/DPS MMcLaughlin/MM DLew/DCL DATE 07/17/07 07/17 /07 07/17/07 07/18 /07 OFFICIAL RECORD COPY Region I Form 83 (Rev. July 2, 2003)