Nuclear, Outage Management

Entergy’s Arkansas Nuclear One Unit 1 returns to service

Arkansas Nuclear One‘s Unit 1 reconnected to the grid at 10:43 p.m. CDT August 7 after a restoration effort involving ANO and Entergy Nuclear workers, government officials and multiple third-party experts.

Prior to restarting, ANO’s Unit 1 required restoration, including damage evaluation, repairs to non-nuclear plant components and rescheduling the unit’s refueling activities. The restoration was necessary following the collapse of a contractor’s crane while moving a generator stator out of the turbine building, a non-nuclear part of the plant.

All told, Entergy employees and contractors devoted more than 790,000 hours of effort to the unit’s safe return to service. The restoration effort saw 55 tons of steel erected and 93 cubic yards of concrete placed — in addition to hundreds of cable installations, switchgear replacements and electrical repairs.

ANO workers developed a startup monitoring plan to ensure the plant achieved a safe and controlled restart. The plan focused on both equipment and systems, including walk-downs by plant staff, extensive monitoring and testing activities, increased training, augmented crews and increased oversight. These plans were developed and challenged by both internal and external ANO subject matter experts.

Unit 1 has been offline since Sunday, March 24 when the plant entered its scheduled refueling outage.