NRC CITES PILGRIM NUCLEAR POWER PLANT FOR INSPECTION FINDING

OF LOW TO MODERATE SAFETY SIGNIFICANCE

The Pilgrim nuclear power plant will receive additional oversight from the Nuclear 

Regulatory Commission following the finalization of a “White” (low to moderate safety 

significance) inspection finding for the facility in Plymouth, Mass.

 

The inspection finding involves the failure of Pilgrim control room operators to follow 

appropriate standards and procedures on reactivity control during a start-up of the reactor on 

May 10, 2011. This failure contributed to an unrecognized subcriticality, or the reactor going 

below power-production levels, followed by an unrecognized return to criticality and a 

subsequent automatic reactor scram, or shutdown. The shutdown was safely carried out.

An NRC team identified the finding during a Special Inspection initiated on May 16th at 

Pilgrim, which is owned and operated by Entergy Nuclear. The Special Inspection was launched 

in response to the May 10th event.

“When it comes to the job of controlling the reactor, unyielding adherence to standards 

and procedures is essential,” NRC Region I Administrator Bill Dean said. “While the plant’s 

automatic safety systems assured that this event did not compromise plant safety or adversely 

impact the environment, this clearly was a significant operational event. The NRC fully expects 

plant personnel to learn from this experience and take steps to ensure there is not a recurrence.”

In an inspection report issued in September, the NRC issued Entergy a Preliminary 

“White” finding for the event. The company provided a written response to the finding on Oct. 

3rd. In that response, the company said it disagreed with the NRC’s determination of risk 

associated with the event. The NRC, as part of its final significance determination report, 

answered that it believes the risk classification is appropriate when all factors, including human 

performance errors identified during the inspection, are factored in.

Further, Entergy said it had taken the reactor scram event very seriously and instituted 

numerous corrective actions, including the completion of a case study of the event, the results of 

which were provided to control room operators; the retraining of control room operators on 

NRC NEWS

U.S. NUCLEAR REGULATORY COMMISSION

Office of Public Affairs, Region I 

475 Allendale Road, King of Prussia, Pa. 19406

E-mail: opa1@nrc.gov 

Site: www.nrc.gov

Blog: http://public-blog.nrc-gateway.gov

No. I-11-042

Contact: Diane Screnci, (610) 337-5330

 Neil Sheehan, (610) 337-5331

Nov. 21, 2011

Email: OPA1.RESOURCE@nrc.gov
criticality operations; and the establishment of management oversight in the control room for 100 

percent of the time when the reactor is in start-up mode.

At a future date, the NRC will perform a supplemental inspection at Pilgrim to evaluate 

the company’s root-cause analysis of what occurred during the event and its corrective actions.

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