Illinois EPA grants Dresden Nuclear Power Station Provisional Variance from Discharge Requirements

Springfield—The Illinois Environmental Protection Agency (Illinois EPA) has granted the Exelon Dresden Nuclear Power Station a provisional variance from the National Pollutant Discharge Elimination System (NPDES) permit thermal limits, due to recent extremely warm weather conditions and high demand for electricity. 

Dresden is a nuclear-fueled steam electric generating facility located on the Illinois River near Morris in Grundy County.  Circulating water used to cool and condense steam from the generating process is discharged into a cooling pond and then into the Illinois River.  It does not come into contact with any radioactive components and does not have any impact on radiation risk. 

Dresden’s NPDES permit places thermal limits on the effluent based on ambient river temperatures during a given season, and gives it an allowance of excursion hours to use if its discharge exceeds the temperature.  Because of the unusually hot weather, the river temperature at the intake has exceeded temperature standards.  The provisional variance is needed because the capacity of the river to dissipate heat has been reduced, causing the facility to exhaust the permitted excursion hours. In addition, the weather is creating unusually high demand for electricity.

During the variance period, Dresden Station must continuously monitor discharge and receiving water temperatures and must visually inspect all discharge areas at least four times each day to assess the impact on aquatic life.   It must also notify the Illinois EPA and the Illinois Department of Natural Resources if aquatic life is affected. If the increased discharge temperature results in adverse environmental impact, appropriate reparations must be conducted.

Dresden  must continue to meet all other effluent conditions in its NPDES permit along with additional conditions contained in the provisional variance but not expressly listed above. 

The Illinois EPA has determined that any environmental impact from the variance would be closely monitored, and the Agency will be notified immediately of any adverse impacts; no reasonable alternative appears to be available; no public water supplies will be affected; no federal regulations would prohibit granting the request; and the facility would face an arbitrary and unreasonable hardship if the Illinois EPA did not grant the requested variance. 

The provisional variance will run through July 16, 2012.   All other NPDES permit requirements will remain in effect.

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