For U.S. nuclear plants now undergoing decommissioning and those about to begin the process, environmental remediation has remained relatively consistent on the nuclear side with respect to contaminated soil and groundwater cleanup. However, non-radiological chemical remediation has been shifting as new and emerging compounds are getting attention from the public and from the Environmental Protection Agency and state agencies.
In the past few years, technological advances in laboratory methods have led to an understanding of the health effects and prevalence of per- and polyfluoroalkyl substances (PFAS), which have been dubbed the “forever chemicals.” PFAS are an anthropogenic class of more than 3,000 chemicals that have been manufactured globally for use in products such as nonstick cookware; water-, grease-, and stain-resistant materials; food packaging; and—most relevant to nuclear plants—fire suppression foams.
These chemicals have gained regulatory and public attention due to their persistence in the environment (much like radiological contamination), and we now have the ability to detect them at low, part-per-trillion levels. This technology has led to health-based cleanup standards set at levels hundreds or thousands of times lower than those for more classic contaminants such as polychlorinated biphenyls (PCBs).
At nuclear plants, PFAS are typically associated with aqueous film forming foam used for fire suppression or in fire training operations. Because they do not degrade or decay over time and migrate quickly in groundwater, PFAS are commonly found in soils and groundwater. They are also found in septage due to their ongoing presence in food packaging products and other common household items. As a result, PFAS are an issue for plants that are permitted to dispose of their septic sludge by treating and then “landfarming” the biosolids.
PFAS are emerging as a complicating factor in nuclear power plant decommissioning because state environmental regulations govern the chemical (nonradiological) aspects of decommissioning, outside of and in addition to the Nuclear Regulatory Commission’s regulatory authority, which has opened up new areas for states to regulate site remediation and closure.