Exelon Limerick and U.S. Nuclear Regulatory Commission officials agree that diverted water released during a recent routine procedure was well within the station’s permitted radiological effluent limits.
A bigger concern, however, is the reason for the spill, a Nuclear Regulatory Commission official said.
Exelon's Limerick Generating Station -- a nuclear power plant located in Montgomery County, roughly 20 miles northwest of Philadelphia -- on March 19 performed a scheduled and permitted water release.
"During a release, mildly radioactive water is pre-mixed with hundreds of thousands of gallons of non radioactive water from Limerick’s cooling towers before it is pumped through a network of pipes to the Schuylkill River," said Dana Melia, Exelon's communications manager at the Limerick plant, via email.
But the water took an unexpected path during the recent release.
"A pipe vent overflowed, causing water to flow into a designated spillway nearby," Melia said. "A restriction in the pipe caused some of the water to back up and exit through a pipe vent."
Most of the spilled water ended up at its target destination - the river, she said.
Although several thousand gallons of water were involved, the spill was contained in a small area on plant property and quickly remediated, she said.
"Water samples taken at the site confirmed that the diverted water was well within the station’s permitted radiological effluent limits," Melia said. "The recorded levels represented a fraction of permitted limits and therefore posed no environmental or public health risks."
Because the release was temporary, limited to station property and posed no environmental or public health risks, the plant did not meet the criteria for an official NRC notification, she said.
"Regardless, within 24 hours, we notified the NRC, local and state officials, as well as area stakeholders as a courtesy, in keeping with our commitment to proactive community and stakeholder outreach," Melia said. "The NRC is currently reviewing the issue and our response to see how it compares to similar issues reported at other stations and we await their decision."
On Friday, NRC Public Affairs Officer Neil Sheehan agreed the spill itself was far below federal safety levels.
The bigger concern is the reason for the spill, he said.
"It's an issue that we're continuing to look at," Sheehan said. "Obviously we want to ensure that they address the problem ... so this doesn't happen again."
The NRC sent officials to investigate the spill the same day it happened. While the search for an answer remains, findings will be included in the agency's mid-May inspection report, he said.
Meanwhile, NRC officials will be available to answer questions about the spill at an open house in Limerick on Wednesday.
"Our staff members ... would be prepared to discuss it," Sheehan said.
Nuclear Regulatory Commission staff will conduct an open house, from 6 to 8 p.m. April 18, regarding the agency’s annual assessment of safety performance for the Limerick nuclear power plant.
The event will be held at the Limerick Township Municipal Building, 646 W. Ridge Pike.
The meeting format will allow citizens to discuss plant-related topics on a one-on-one basis with NRC inspectors assigned to the plant and their NRC Region I supervisor.