Under contract to Fluor/Babcock & Wilcox Portsmouth (FBP), Geiger Brothers has participated in studies of the geology at locations being investigated for On-Site Disposal Cell (OSDC) construction on U. S. Department of Energy (DOE) property in Pike County. The work is part of the Portsmouth Gaseous Diffusion Plant (GDP) Decontamination & Decommissioning (D&D) program. Fluor-B&W Portsmouth, LLC (FBP) is DOE’s prime contractor performing D&D and remediation.
An OSDC, in conjunction with off-site shipment of higher-hazard materials, is an alternative being considered for more than 2.1 million cubic yards of material that will be generated from D&D. The OSDC approach would allow for disposition of low-level radioactive, mixed low-level radioactive and Toxic Substances Control Act (TSCA) wastes within the boundaries of the GDP site.
The GDP site is undergoing remediation pursuant to the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource Conservation and Recovery Act (RCRA).
Using an excavation subcontractor, Geiger Brothers was responsible in early 2012 for the initial OSDC test pit excavation. The excavation was made to help assess the geology as part of the feasibility study for construction of the engineered disposal facility. The excavation was approximately 19 feet by 50 feet with 12-foot walls.
Geiger Brothers was responsible for pre-mobilization including submittals and training, mobilization and site preparation including erosion and sediment control and construction fencing, site restoration, clean-up and demobilization and for managing the removal of top soil and overburden soil and rock, rock trenching, diversion berm, rock excavation, stockpiling, dewatering, backfilling and other specific scope-required activities to complete the test pit excavation and for FBP to perform evaluations.
FBP continued geological studies later in 2012. A trench dug 27-feet deep and 30 inches wide further revealed geology and confirmed results of previous soil and rock samples. By extending a camera into the narrow trench, crews from Geiger Brothers and the excavation subcontractor were able to safely and efficiently capture images of the soil composition and layer structure.
Scientists and engineers examined density, permeability and composition of soils and underlying rock formations, in particular checking for flow of water and the presence of fractures that could conduct water.
If constructed, the OSDC design will reflect all geological and hydrogeological information and contain engineered liner and cap systems with multiple layers of barriers and drainage layers to encapsulate the material and comply with stringent Department of Energy (DOE), United States Environmental Protection Agency (USEPA) and Ohio Environmental Protection Agency (OEPA) regulations. DOE and OEPA will make the final decision for site-wide waste disposition with input from members of the Site Specific Advisory Board (SSAB) and the community. Final engineering design and construction processes for the OSDC and necessary support facilities then would be initiated.
(Photos/content are the property of Fluor-B&W Portsmouth LLC and the U.S. Department of Energy and are being published with the permission of Fluor-B&W. These photos/content may not be re-printed without the approval of Fluor-B&W.)
Excavation as it began at an OSDC test site in the northeast part of the DOE property. Upon completion, the excavation was about 19 x 50 feet with 12-foot walls.
Members of the Portsmouth plant’s Site Specific Advisory Board toured the geologic study site in late February. Of particular interest was a cross section of the geology of the excavation. The group received updates on studies under way to provide information to DOE for the decision on how to dispose of material from plant D&D over the coming years.
The excavator operator digs a trench 27 feet deep for subsequent geotechnical study.
Representatives of Geiger Brothers and its subcontractor secure a camera to the excavator bucket to capture images of the soil composition and layering structure in the narrow 27-foot-deep trench.