Federal regulators said Tuesday they had placed Entergy’s Waterford 3 nuclear power plant in Killona under increased oversight because of improper calibration of radiation monitors, which could have triggered unnecessary evacuations.
The Nuclear Regulatory Commission notified Nuclear Entergy that its additional oversight will include at least one special inspection. The commission labeled the risk associated with the issue as low to moderate.
The agency found that radiation monitors at the plant were being improperly calibrated between January 2011 and February 2022, and that despite numerous opportunities to correct the errors, they remained in place until discovered by Waterford workers at the beginning of this year.
An inspection conducted between April 24 and May 17 of this year found that the calibration resulted errors in readings that were 69% to 76% greater than the current potential radiation levels. During an accident involving a release of radiation, the inaccurate readings could result in a “general emergency” declaration, which could trigger evacuations and unnecessary risk to the public, the inspection concluded.
The NRC said the violation resulted in a “white” plant performance finding on its color-coded scale of green, white, yellow and red. White means low to moderate safety or security significance.
Entergy argued the error rated only a green — very low safety significance — in part because the company said it could have found other ways of accurately measuring radiation releases in the event of an accident.
The finding puts the Waterford facility under more careful federal watch. NRC will keep the plant under increased oversight until the agency conducts additional independent reviews to verify that plant staff has identified the cause of the problem and taken appropriate steps to assure it doesn’t happen again. That oversight will include a special inspection of the Waterford facility by NRC officials to review the risk issues associated with the monitor calibration problem.
“Although we are disappointed in Waterford 3 in regulatory columns, said the plant enters it’s thought all move and have plans to bring the plants back to column 1, where other Nuclear Entergy Nuclear are now,” spokesman Michael Bowling. The first column is for plants without regulatory issues.
“It’s important to note that Entergy both identified and reported the issue to regulators, and the finding had no actual consequences on safety. We are committed to keeping our plants, employees and communities safe and secure as we continue providing them with reliable clean energy, ” he said.
Waterford 3 is owned by Entergy Louisiana and operated by Entergy Nuclear, which also operates three other Entergy-owned nuclear plants in Louisiana, Mississippi and Texas. The plant’s 1,152 maximum megawatt electricity production represents about 30% of Entergy Louisiana’s total generation.
An inspection report monitoring a February letter said that beginning in 2000, reactor staff began increasing the time between routine calibrations of 41 monitors used to measure radiation doses in various areas in and around the plant, radiation in liquid or gaseous effluents released from the plant and radiation related to the plant’s operating processes.
Some of the monitors were changed from three-year recalibration schedules to nearly seven years, with a few extended to nine years. Some monitors requiring recalibration every 18 months were extended to three and five years.
The inspectors found that plant officials had identified the issue four months before the inspection. Still, only nine of 41 radiation monitors had been recalibrated by February, and only one of those had been returned to its proper calibration schedule by the time inspectors visited the site.
“Additionally, 29 of the 41 radiation monitors are still past due on their required calibration frequencies,” the inspection report said. “There is still no justification for the current frequencies.”
By the time of the follow-up April-May inspection, all the monitors had been properly recalibrated.
This work is supported with a grant funded by the Walton Family Foundation and administered by the Society of Environmental Journalists.