20 Soil and Water Cleanup

Many U.S. nuclear power plants have permanently shut down and are in some phase of decommissioning. They include research reactors, other research facilities, and a small number of other commercial nuclear facilities, such as three commercial spent fuel reprocessing plants. There are hundreds of DOE nuclear facilities, i.e., reactors, fuel reprocessing plants, research facilities, and laboratories that supported a wide variety of operations using hazardous substances in the production of nuclear weapons. The DOE has restored many of its nuclear sites and cleaned up many hazardous waste sites. The decommissioning of commercial, private, and DOE-owned sites has resulted in the development of effective cleanup technologies and practices.

Radioactive and hazardous waste constituents found in the soil and groundwater during decommissioning got there because of spills, system upsets, maintenance activities, and outdated work practices. Only a few chemical processes support electricity production at commercial power reactors, but nevertheless, activities at these sites released contaminants to the environment. An example of such an activity is work performed in on-site analytical laboratories. These laboratories were often the source of radioactive and chemical agents that reached the environment via sink and floor drains. At some of the older facilities, both radioactive and chemical contaminants were found in leach fields where the contaminants tended to accumulate.

The primary radioactive contaminants in the soil or groundwater at a commercial site are ¹³⁷Cs, ⁹⁰Sr, ⁶⁰Co, and ³H. The source of tritium in the groundwater is. generally water leakage from the spent fuel storage pool that tends to occur over many years of operation, Insoluble radioactive contaminants tend to be trapped in the soil and are not easily transported by groundwater movement, therefore tend to remain in localized areas.