The company charged with decommissioning a shuttered nuclear power plant in Genoa has reported elevated levels of radioactive material in groundwater.
LaCrosseSolutions, a subsidiary of the nuclear waste disposal company EnergySolutions, announced Monday that it had detected elevated levels of tritium in a monitoring well near the former reactor building.
According to a report filed with the Wisconsin Department of Natural Resources, EnergySolutions reported a reading of 24,200 picocuries per liter in water taken from a monitoring well on Feb. 1. The water was tested by an independent lab on Feb. 14.
The Environmental Protection Agency’s limit for tritium in drinking water is 20,000 picocuries per liter, although the monitoring well was just 25 feet below the surface and not used for human consumption.
“Based on the information we have so far this should not have any impact on public health and safety,” said Nuclear Regulatory Commission spokeswoman Viktoria Mitlyng.
EnergySolutions spokesman Mark Walker said off-site wells have not been tested because the contamination appears to be contained in shallow water on site.
Mitlyng said NRC inspectors were on site when the tritium was discovered and are working with LaCrosseSolutions to determine the cause. The environmental consulting firm Haley & Aldrich has been contracted to assist in further testing and to develop a groundwater monitoring plan.
LaCrosseSolutions has stopped dismantling the containment tower as inspectors try to figure out what caused the leak, but Walker said other decommissioning activities are continuing.
Dairyland Power Cooperative workers at the neighboring coal-fired generator were instructed to stop drinking well water on March 6, although test results received Monday indicated water from the on-site well is safe to drink, according to LaCrosseSolutions.
Tritium is a naturally occurring isotope of hydrogen that emits a weak form of radiation that doesn’t travel far and cannot penetrate the skin, according to the NRC.
Dairyland, which operated the 50-megawatt La Crosse Boiling Water Reactor from 1967 to 1987, transferred the site license to LaCrosseSolutions in 2016 to complete the decommissioning process, which was expected to be completed later this year at a cost of about $85 million.
Under the agreement, LaCrosseSolutions will remove everything down to three feet below ground and return the clean site to the La Crosse-based utility. Exposure to radiation at the cleaned site must be below the NRC’s acceptable level of 25 millirem per year from a single source, which is about 2½ times the exposure from a chest X-ray.
The nuclear reactor vessel was removed in 2007 and taken to a burial site in South Carolina. In 2012, after six years of planning, the spent fuel rods were encased in dry storage casks that will remain in Genoa until the government opens a long-term storage facility.
Note: This story has been updated to correct the date on which elevated levels of tritium were discovered and to accurately reflect the EPA limit for tritium in drinking water.