Nuclear Regulatory Commission Column 4 Recovery

Arkansas Nuclear One

Case Study

Arkansas Nuclear OneDefined Need

Arkansas Nuclear One (Entergy ANO) engaged Marathon Consulting Group (MCG) to lead the project to prepare the station for a successful NRC 95003 inspection. ANO was placed in Column 4, Multiple/Repetitive Degraded Cornerstone, in March 2015 because of two findings of substantial safety significance (Yellow findings) in the Initiating Events cornerstone and in the Mitigating Systems cornerstone. Regulatory recoveries are expensive propositions. Performing the diagnostic portion of the effort requires many thousands of hours of assessment, multiple root and apparent cause analyses, and implementation of an improvement plan, in addition to any technical/equipment repairs or design changes. Column 4 recoveries can cost a site and corporation upwards of $100 million.


  • MCG built the Project Plan, Work Breakdown Structure, Schedule backbone, and financial tracking tools.
  • MCG wrote all the recovery guidance procedures and fostered them through the fleet approval process.
  • MCG used lessons learned to streamline the entire process.
  • MCG developed a significant event and regulatory timeline/storyline to illustrate performance and align the plant staff and team.
  • MCG recommended and screened vendors for assessment work with ANO.
  • MCG built and issued the weekly project progress report and recovery performance indicators.
  • MCG briefed the staff on the 95003 inspection module and the Marathon/Entergy procedures used to implement the process.
  • MCG led each of the phases of the project.
  • MCG guided the station through the inspection phase.


Following completion of the action, numerous improvements resulted:

  • The ANO overall recovery was conducted for 65% of the cost of the previous recovery (less than $80 million).
  • The assessment and cause analysis phases were accomplished within 2.5% of the original estimates.
  • ANO successfully exited Column 4 in May of 2018, as expected.
  • During the recovery ANO moved from INPO 3 to INPO 2 and was removed from increased INPO oversight (Policy Note 14).