Radiation discharge near Philadelphia kept secret from public for weeks — No ‘immediate’ health concerns, says NRC
LIMERICK — “Several thousand gallons” of water containing as much as five-times the government’s “safe” level of radioactive tritium was accidentally released at Exelon Nuclear’s Limerick Generating Station last month and then flushed into the Schuylkill River, The Mercury learned Thursday.
However the concentrations of contamination in the water were considered so low that they presented “no immediate health and safety concerns,” according to the Nuclear Regulatory Agency, which is why the incident was not reported publicly until 23 days after it happened. It was 3 a.m. Monday, March 19 when “a manhole cover overflowed during a scheduled and permitted radiological release,” according to an incident report posted on the NRC web site. “As a result, several thousand gallons of water overflowed briefly, formed puddles in the area, and was discharged” through a permitted discharge to Possum Hollow Creek, which flows from the plant grounds into the Schuylkill River,” according to information from the NRC. The notification issued to the NRC by Exelon stated “several (water) samples showed increased levels of tritium that were well below permitted Commonwealth and Federal effluent limits.” NRC spokesman Neil Sheehan wrote in an e-mail that the “maximum level of radioactivity detected in Possum Hollow Creek . . . on the day of the event was 495 picocuries per liter of tritium.” He noted that the Environmental Protection Agency’s “safe drinking limit for tritium per liter is 20,000 picocuries per liter.” However, Sheehan also noted that one water sample collected from a puddle near the manhole from which the water first emerged, had a tritium concentration of 113,000 picocuries per liter, more than five times the safe drinking water level. “Of course the water leaked out onto the ground on the plant grounds would not be used for” drinking, Sheehan said. However all that water, which Exelon estimated something less than 15,000 gallons, was legally dumped into the Schuylkill River, which is a drinking water source for several downstream communities, including Phoenixville and Philadelphia. But because the contaminated water would be diluted when it hit the Schuylkill, and the concentration of tritium spread out, “calculations indicate that the dose to a member of the public exposed to the contamination would have been a small fraction of the allowable levels,” Sheehan wrote. He said state and county emergency officials were notified, as were township officials. “Composite samples were collected from downstream water companies and no radioactivity attributable to the release was identified,” Sheehan wrote. “It’s important to note that the Limerick and other nuclear power plants routinely release slightly radioactive water to the river, but the releases must be controlled and any levels of radioactivity well within allowable limits,” Sheehan wrote. Because the release was not considered dangerous, Exelon informed the NRC but did not immediately do so in writing. “When formal notifications are made to the state, we expect to receive a written notification to us,” Sheehan explained. “The company initially said it wasn’t clear whether such a submittal was needed (under the reporting requirements of NEI voluntary Groundwater Protection Initiative),” Sheehan wrote. “But we insisted that it was needed, and the company ultimately agreed.” “Because the water release was small and temporary, limited to station property and posed no environmental or public health risks, our initial review concluded that it did not meet NRC criteria for an emergency notification,” Dana Melia, communications manager for the Limerick Generating Station wrote in response to a Mercury inquiry. “Regardless, we made the courtesy notifications because we like to keep stakeholders and community members informed,” she wrote. Melia further noted that “the water that exited the pipe was part of a planned and permitted release, well within state and federal effluent limits.” She further wrote that “most of the spilled water travelled quickly on the surface to its intended destination — the river, and we see no indication from our network of groundwater monitoring wells that it will ever reach a drinking water source.” “Limerick is committed to a comprehensive and proactive environmental monitoring program, which includes routine tests of air, water, soil and agricultural products and we continue to operate well within all state and federal regulations,” Melia concluded. Sheehan wrote that the company “is continuing its investigation as to the causes and long-term corrective actions.” He added that “we had an inspector walking the grounds on the day of the event and have continued to evaluate the details, the company’s actions and any potential impact on public health and safety.” The news comes seven days before the NRC holds its annual “open house” review of the plant’s operation in 2011. The meeting will take place Wednesday, April 18, at the Limerick Township Building, 646 West Ridge Pike, from 6 to 8 p.m. and is open to the public. Follow Evan Brandt on Twitter @PottstownNews