Exelon (NYSE:EXC) has identified water containing tritium in on-site monitoring points at the Dresden nuclear plant in Illinois.
Exelon has notified state and federal regulatory officials and plans to resolve the situation quickly, the company said in a June 8 news release.
“Our monitoring program functioned as designed, alerting us to the presence of tritium early so we can address the issue quickly and effectively,” said Dresden Site Vice President Shane Marik.
A June 10 “event notification report” filed with the Nuclear Regulatory Commission (NRC) said officials believe that elevated levels of tritium have existed at the discharge of the plant since April.
“It has been determined that no greater than 0.1 Curies were discharged from the site. The majority of this discharge was to the Kankakee River via the sewage treatment plant effluent. A small amount, determined to be less than 2%, was discharged to the Morris Illinois sewage treatment facility,” NRC said in the report.
“The system is currently isolated, and not discharging to the Kankakee River,” NRC said.
On Saturday, June 7, the station’s environmental team identified tritiated water in one of the station’s 83 environmental monitoring wells located near a water storage tank. The station will be working around the clock to excavate the area around the tank, find the location of the leak, and make repairs, the company said.
Samples taken from the station’s on-site waste water treatment facility also showed low levels of tritium. The station has not detected any unusual levels of tritium offsite.
The plant’s sample points are tested on a monthly basis, Exelon said.
“We are keeping our commitment to and are firm believers in sharing new tritium findings with the public,” said Marik. “We care about the environment and will be doing everything humanly possible to quickly find the leak source and fix it.”
Dresden’s waste water treatment plant operates in the same manner as all waste treatment facilities following all state and federal regulations. The sanitary wastewater from the plant is cleaned, disinfected and discharged to the Kankakee River, Exelon said.
Tritium concentrations are measured in picocuries per liter of water. A picocurie is one-trillionth of a curie, which is a radiological measurement.
Tritium occurs naturally in the environment in very low concentrations. Most tritium in the environment is in the form of tritiated water, which easily disperses in the atmosphere, bodies of water, soil and rock, Exelon said Today, manmade sources of tritium include commercial and research reactors.
Dresden Generating Station is approximately 60 miles southwest of Chicago. The station’s two nuclear energy units can produce a total of more than 1,800 MW at full power. During 2013 the station had a capacity factor of more than 95%, according to an Exelon website.
Dresden Units 2 and 3 are General Electric (NYSE:GE) boiling water reactors (BWRs) that began commercial operation in July 1970 and November 1971, respectively. In October 2004, NRC renewed the operating licenses for both units for an additional 20 years, extending them to 2030 and 2031.
In 1978, Dresden Unit 1 was retired and is now designated a Nuclear Historic Landmark by the American Nuclear Society. While in operation, the unit was capable of generating 210 MW of electricity.