Persistence of Surrogate Radionuclides on Wastewater Collection System Infrastructure
Citation:
Szabo, Jeff, R. Silva, J. Webster, AND L. Heckman. Persistence of Surrogate Radionuclides on Wastewater Collection System Infrastructure. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-21/006, 2021.
Impact/Purpose:
Contamination from a radiological dispersal device, improvised nuclear device or nuclear power plan accident could be widespread. Cleanup activities or precipitation events could result in radioactive contamination entering a wastewater or stormwater collection system. In this study, collection system infrastructure materials such as brick, clay, concrete, high density polyethylene, iron, polyvinyl chloride (PVC), and rubber were conditioned in wastewater flowing through six 6-inch (15.2 cm) diameter PVC pipes for two months. Conditioning allowed biofilms to form and wastewater solids to accumulate on the coupons surface. Subsequently, non-radioactive cesium chloride, cobalt chloride and strontium chloride were injected into the wastewater flow, and persistence on the infrastructure coupons (excised sample materials) was determined over time. Flow in each channel was approximately 50 gallons per minute (189.2 liters per minute), and each non-radioactive salt was spiked into the flow at 5 mg/L. This setup was designed to determine if non-radioactive surrogates for radionuclides would adhere to or persist on common collection system infrastructure materials. Results for cesium and cobalt showed that metal adhesion to conditioned infrastructure materials was undetectable. Strontium was detected on concrete coupons at levels above the method detection limit. However, further analyses of the concrete suggested that strontium in the concrete matrix was being detected, not strontium from the contaminant injection. Although the data suggests that none of the surrogate radionuclides adhered to or persisted on collection system infrastructure materials, research with real radionuclides could confirm these results.
Description:
EPA Report; Results for cesium and cobalt showed that metal adhesion to conditioned infrastructure materials was undetectable. Strontium was detected on concrete coupons at levels above the method detection limit. However, further analyses of the concrete suggested that strontium in the concrete matrix was being detected, not strontium from the contaminant injection. Although the data suggests that none of the surrogate radionuclides adhered to or persisted on collection system infrastructure materials, research with real radionuclides could confirm these results.