ML13099A244
| ML13099A244 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/09/2013 |
| From: | Allen D B, Sanchez A A NRC/RGN-IV/DRP |
| To: | |
| AMT / Don Allen | |
| References | |
| PNO-IV-13-002A | |
| Download: ML13099A244 (2) | |
Text
April 9, 2013 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE -- PNO-IV-13-002A
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 IV, Arlington, Texas, staff on this date.
Facility Arkansas Nuclear One, Units 1 and 2 Entergy Russellville, Arkansas Dockets: 05000313; 05000368 License Nos. DPR-51; NPF-6 Licensee Emergency Classification
_ _Notification of Unusual Event
_Alert _Site Area Emergency
_General Emergency X Not Applicable
SUBJECT:
AUGMENTED INSPECTION TEAM ONSITE AT ARKANSAS NUCLEAR ONE - UPDATE
DESCRIPTION:
This preliminary notification provides an update to Preliminary Notification PNO-IV-13-002, which was issued on April 2, 2013. On April 8, 2013, the Nuclear Regulatory Commission commenced an Augmented Inspection Team (AIT) assessment of the circumstances surrounding the March 31, 2013, loss of offsite power for Arkansas Nuclear One (ANO), Unit 1, and the reactor trip and subsequent Notification of Unusual Event for ANO Unit 2.
AITs are used by the NRC to review more significant events or issues at NRC-licensed facilities. The four-member team includes in spectors from the NRC's Region IV office in Arlington, TX, and NRC's Office of Nuclear Reactor Regulation.
On March 31, 2013, during transfer of the 500 ton ANO Unit 1 main generator stator, the lifting rig failed. The main generator stator fell approximately 30 feet into the train bay and caused structural damage to the Unit 1 turbine building. For ANO Unit 1, which was in a refueling outage, this drop caused a loss of offsite power. This resulted in the Unit 1 Emergency Diesel Generators (EDGs) operating to provide power to vital electrical loads. ANO Unit 2 experienced a reactor trip from 100 percent power after the falling stator and crane components caused a reactor coolant pump electrical breaker to open. About 1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> later, water from a damaged fire suppression system piping caused a breaker failure in ANO Unit 2, resulting in loss of power to one vital electrical bus and a Notification of Unusual Event. The associated EDG for Unit 2 started and supplied vital electrical loads. Both units are currently stable and remain shutdown.
Offsite power has been restored to the safety-related electrical buses on both units. The licensee is assessing the damage to both units and is investigating the cause of the failure of the lifting rig.
State and local officials have been informed.
This preliminary notification is issued for information only, and will be updated again as necessary as more information becomes available.
This information presented herein has been discussed with the licensee and is current as of
5:00 p.m. (CDT) on April 8, 2013.
CONTACTS:
Don Allen, Branch Chief, 817-528-3439 Fred Sanchez, Senior Resident Inspector, ANO
ADAMS ACCESSION NUMBER: ML13099A244