NRC Issues Comprehensive Inspection Report on Arkansas Nuclear One

Victor Dricks
Senior Public Affairs Officer
Region IV

The NRC has just issued a lengthy report documenting the results of a comprehensive inspection conducted earlier this year at Arkansas Nuclear One, or ANO. The plant, operated by Entergy Operations, Inc., is located in Russellville, Ark.

anoOn March 4, 2015, the NRC moved ANO into Column 4 of the agency’s Action Matrix (where operating plants with significant performance issues receive the second highest level of NRC oversight). This followed inspection findings of substantial safety significance stemming from a heavy equipment incident as well as degraded flood protection at the site. As part of its increased oversight of ANO, the NRC conducted a rigorous, independent, diagnostic assessment of the performance, programs and processes at the site earlier this year.

A team of 27 NRC inspectors from all four NRC regional offices and NRC headquarters spent about 3,800 hours of direct inspection. They concluded that despite its problems, ANO has been –- and continues to be — operated safely. This judgement was based on the fact there have not been any safety-significant inspection findings since the plant’s move to Column 4. Inspectors also concluded the robust plant design had not been compromised and the ANO staff’s operational focus has improved.

In addition to inspecting ANO’s program for evaluating and correcting performance issues, the NRC team developed insights into the causes for the performance decline at ANO. The team also evaluated the adequacy of a third-party safety culture assessment ANO commissioned. Additionally, the NRC inspection included an assessment of how well ANO determined the root causes for its performance deficiencies and developed performance improvement programs.

PI_ROPBased on Entergy’s review of the causes of the performance decline, the independent third-party nuclear safety culture assessment findings, and the results of the NRC’s independent diagnostic evaluation, “the team determined that Entergy understands the depth and breadth of performance concerns associated with ANO’s performance decline,” NRC Region IV Administrator Marc Dapas said in a letter to Entergy officials accompanying the report.

Dapas further stated that “effective implementation of the comprehensive recovery plan, supported by the allocation of adequate resources and continued enhanced oversight by Entergy leadership, should lead to substantial sustained performance improvement.”

The NRC team documented 16 findings of very low safety significance. The 243-page report goes into a high level of detail about the results of the inspections, but here are some highlights:

  • Resource reductions and leadership behaviors were the most significant causes for ANO’s declining performance. Entergy reduced resources across its fleet in 2007 and 2013, but it did not adequately consider the unique staffing needs for ANO created by having two units with different designs.
  • ANO management did not reduce workloads through efficiencies or the elimination of unnecessary work, as was intended as part of the resource reduction initiatives. Leaders attempted to prioritize work with the available resources, but they did not address expanding work backlogs. Over time, this contributed to equipment reliability challenges.
  • An unexpected increase in employee attrition between 2012 and 2014 caused a loss in experienced personnel, which led to a reduced capacity to accomplish work, and an increased need for training and supervision.
  • Since 2007, the reduced resources created a number of changes that slowly began to impact equipment reliability. The Entergy fleet reduced preventive maintenance and extended the time between some maintenance activities.

Although ANO is in the early stages of implementing its comprehensive recovery plan, there have been some notable improvements in station performance. ANO implemented prompt action to improve operator performance, for example, and ANO management decision making has increased in rigor and conservatism. The NRC resident inspectors have noted a number of examples that indicate the operations department is taking a leadership role and raising the standards across the station. Also, employees are engaging in discussions of the potential risk of plant activities, and the corrective action program rigor has improved. And ANO staff have begun to question the status quo and emphasize the need to assess and address problems.

The NRC inspection team reported its preliminary findings at an April 6 public meeting held in Russellville. The NRC is preparing a Confirmatory Action Letter to document Entergy’s commitments to address performance issues identified in the inspection report and the key actions needed to ensure sustained improvement in safety performance. The NRC expects to issue this letter and make it publicly available later this month.

NRC will conduct quarterly inspections to verify that ANO successfully undertakes all necessary improvement actions. From these inspections, NRC will independently determine whether ANO’s corrective actions have been effective and whether, after a period of sustained good performance, the NRC can return ANO to normal oversight.

The NRC Makes a Determination After Last Year’s Crane Collapse

Victor Dricks
Senior Public Affairs Officer
Region IV

 

Last year, the Arkansas Nuclear One facility experienced a tragic incident when a crane collapsed. One person was killed, eight were injured and important plant equipment was damaged. The NRC has now issued two “yellow” inspection findings as a result. The “yellow” means we found substantial safety significance related to the incident.

arkansasWorkers were moving a massive component out of the plant’s turbine building when the incident occurred. Unit 1 was in a refueling outage at the time, with all of the fuel still in the reactor vessel. At the time, Entergy Operations declared a Notice of Unusual Event, the lowest of four emergency classifications used by the NRC, because the crane collapse caused a small explosion inside electrical cabinets. The damaged equipment caused a loss of off-site power. The NRC’s senior resident inspector had driven to the plant to personally survey the damage and monitor the licensee’s response from the plant’s control room.

Here’s why NRC decided the incident had substantial safety significance even though both plants were safely shut down and there was no radiological release or danger to the public: Emergency diesel generators were relied upon for six days to supply power to heat removal systems.

The falling turbine component damaged electrical cables 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 when the heavy component fell and hit the turbine building floor. Unit 2 never completely lost offsite power, and there was a way to provide it with emergency power using the diesel generators.

The NRC conducted an Augmented Team Inspection. We prepared a detailed chronology of the event, evaluated the licensee actions in response, and assessed what 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 was a result of the licensee’s failure to adequately review the assembly design and to do an appropriate load test.

We held a public meeting in Russellville, Ark., on May 9, 2013, to discuss the team’s initial findings. From its follow-up inspections, the NRC issued a preliminary red finding to Unit 1 and a preliminary yellow finding to Unit 2. These are 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 right level of agency oversight for the facility and notify Entergy officials of the decision in a separate letter.