The company in charge of decommissioning a nuclear power plant in Genoa says it has found the source of radioactive groundwater discovered last year and that the contamination did not affect drinking water or the nearby Mississippi River.
LaCrosseSolutions, a subsidiary of the nuclear waste disposal company EnergySolutions, in March reported elevated levels of tritium in a monitoring well at Dairyland Power Cooperative’s La Crosse Boiling Water Reactor (LACBWR), the state’s first nuclear power plant to undergo decommissioning.
Records show that tritium levels spiked in December 2017 in water samples taken about 25 feet below the ground.
A sample from Feb. 1 registered 24,200 picocuries per liter, just below the Environmental Protection Agency’s limit for drinking water.
According to a report filed earlier this month with the Nuclear Regulatory Commission, the environmental consulting firm Haley & Aldrich traced the contamination to an exhaust vent installed in the former reactor building as part of the demolition.
The vent was just above a pit of stormwater and melted snow.
EnergySolutions spokesman Mark Walker said tritium was released into the air inside the reactor building as concrete was broken into smaller pieces.
A radioactive isotope of hydrogen, tritium bonds with airborne water molecules.
According to the report, water vapor from inside the plant condensed as it reached the outside air and combined with the runoff, which found its way into a shallow aquifer.
+3 Dairyland contracted with EnergySolutions in 2016 to remove the remaining buildings and transferred the site license to the Salt Lake City-based company, which used a similar license arrangement in decommissioning the Zion Nuclear Power Station near Chicago.