Deepwater, New Jersey
The DuPont site is a Formerly Utilized Sites Remedial Action Program (FUSRAP) site that was used from 1942 to 1947 to process and refine uranium for the Manhattan Engineering District project. The site is currently home to an operational chemical facility owned by The Chemours Company. FUSRAP contaminants of concern (COCs) include U-234, U-235, U-238, Th-230, Ra-226; however, those COCs are comingled materials with chemicals, including tetraethyl lead, BTEX, VOCs, SVOCs, heavy metals, and pesticides.
As the self-performing prime contractor, Sevenson’s scope of work includes the handling of radiologically contaminated debris; excavation of >80,000 CY of radiologically contaminated soil and debris ranging from 0–16 ft. BGS; 2,330 LF of sheet pile installation; transportation and disposal (T&D) via railcar of >79,100 CY; operation of an on-site rad lab, where Sevenson has collected and analyzed gamma spectroscopy and gas-flow proportional counting; and operation and maintenance of an on-site 200-GPM WWTP to year-round operations, treating >22.2M gallons of water. During radiological excavation, Sevenson utilizes Precision Trimble RTK GNSS receivers and machine control systems with an on–site base station to guide mechanical excavators for accurate dredging. Real-time position data, including pitch, roll, boom, stick, and bucket angles, is tracked through inclinometers to ensure adherence to complex dredge templates. Sevenson then integrates RAD detectors positioned by GNSS rovers to map data onto a GIS platform. Excavation, RAD scan data, and sample results are then overlaid in GIS to assess the need for further excavation or backfill.