Preliminary Hazard Classification for the In Situ Redox Manipulation Treatmentfor the 100-HR-3 Operable Unit (100-D Area)(Revision 2)

摘要

In situ redox (reduction-oxidation) manipulation treatment for chromatecontamination will be performed in the aquifer on the west side of the 100-D Area (100-HR-3 Operable Unit) of the Hanford Site. This in situ redox manipulation treatment involves the pumping of a solution, sodium dithionite, into ground wells to reduce the hexavalent chromium dissolved in groundwater to trivalent chromium, which will precipitate the chromium from the groundwater as immobile Cr(OH)(sub 3). This document serves as the preliminary hazard classification (PHC) for the 100-D Area In Situ Redox Manipulation Project. The PHC was prepared in accordance with the requirements for nuclear safety (DOE-RL 1996). Per these requirements, the PHC is based on the total hazardous substance inventories associated with the in situ redox treatability activities. Based on the estimated hazardous substance inventory contained within the evaporation pond, which will be used to evaporate the water extracted from the wells treated by the in situ redox method, the PHC for the facility was determined to be non-nuclear, low hazard.