No: IV-14-014 June 24, 2014

CONTACT: Victor Dricks 817-200-1128

Lara Uselding 817-200-1519 

 NRC Issues Two Yellow Findings to Arkansas Nuclear One 

The Nuclear Regulatory Commission has determined that two inspection findings at the 

Arkansas Nuclear One facility in Russellville, Ark., issued in connection with a 2013 heavy equipment 

handling incident are “yellow,” or of substantial safety significance. The plant is operated by Entergy 

Operations, Inc.

The NRC evaluates regulatory performance at commercial nuclear plants with a color-coded 

process that classifies inspection findings as green, white, yellow or red in order of increasing safety 

significance. 

Workers were moving a 525-ton component out of the plant’s turbine building during a 

maintenance activity when a temporary lifting assembly collapsed on March 31, 2013, causing the 

component to fall, damaging plant equipment, killing one person and injuring eight others. Unit 1 was 

in a refueling outage at the time, with all of the fuel still in the reactor vessel, safely cooled. Entergy 

officials declared a Notice of Unusual Event, the lowest of four emergency classifications used by the 

NRC, because the incident caused a small explosion inside electrical cabinets. The damaged equipment 

caused a loss of off-site power. Emergency diesel generators were relied upon for six days to supply 

power to cooling systems.

The falling turbine component damaged electrical cables and equipment needed to route power 

from an alternate AC power source to key plant systems at both units. This condition increased risk to 

the plant because alternate means of providing electrical power to key safety-related systems was not 

available using installed plant equipment in the event the diesels failed. 

Unit 2, which was operating at full power, automatically shut down when a reactor coolant 

pump tripped due to vibrations caused by the heavy component hitting the turbine building floor when 

it fell. Unit 2 never completely lost off-site power, and means existed to provide emergency power 

using the diesel generators.

NRC Resident Inspectors responded to the site the day the incident occurred. The NRC 

conducted an Augmented Team Inspection, prepared a detailed chronology of the event, evaluated the 

adequacy of licensee actions in response to the incident, and assessed the factors which may have 

contributed to the incident. Worker safety issues are the responsibility of the Occupational Safety and 

Health Administration, which conducted an independent inspection of the incident. The NRC 

determined that the lifting assembly collapse resulted from the licensee’s failure to adequately review 
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the assembly design and ensure an appropriate load test in accordance with its procedures or approved 

standards.

The Augmented Team Inspection report documented information gathered from the initial 

inspection and identified areas for further inspection follow-up. The NRC held a public meeting in 

Russellville on May 9, 2013, to discuss the team’s findings. 

From its follow-up inspections, the NRC identified the preliminary red and yellow findings 

documented in a March 24 inspection report. NRC held a regulatory conference with Entergy officials 

on May 1, and after considering information provided by the licensee determined that yellow findings 

were appropriate to characterize the risk significance of the event for both Unit 1 and 2.

The NRC will determine the appropriate level of agency oversight and notify Entergy officials 

of the decision in a separate letter.