Work Description

When it planned to remove a shielding wall adjacent to a no-longer-used 40 MeV Linear Accelerator (LINAC), the U.S. Naval Research Laboratory (NRL) in Washington, DC, relied on Dade Moeller, an NV5 Company,* to use the methodologies outlined in the Multi-Agency Radiation Site Survey and Investigation Manual (MARSSIM) to:

Historical Site Assessment (HSA)

  • Identify potential, likely, or known sources of radioactive materials based on existing information
  • Identify radionuclides of concern and information needed to calculate derived concentration guideline levels (DCGLs)
  • Identify areas that were not impacted with any radiological contamination based on historical use and documentation
  • Assess the likelihood of contaminant migration
  • Implement the Data Quality Objectives (DQO) process described in MARSSIM
  • Prepare a conceptual site model, or site diagram, showing locations of known contamination, areas of suspected contamination, types and concentrations of radionuclides in impacted areas, potentially contaminated media, and locations of potential reference (background) areas
  • Prepare a final narrative Historical Site Assessment report, summarizing the radiological status of the buildings and the activities conducted during the investigation

Radiological Characterization of Building 75, Room 105A

  • Conduct a radiological characterization of the wall
  • Move more than 20 samples of concrete from the inner side of the wall for gamma spectral analysis via gamma spectrometry with a hyper pure Germanium detector system
  • Evaluate the samples with the Residual Radioactivity (RESRAD) computer code to determine the maximum dose to a bystander from radioactive constituents present in the concrete wall
  • Determine which portions of the wall could be disposed as standard construction debris in a municipal landfill, and which portions were not suitable for such disposal
  • Determine acceptable, realistic, and cost-effective methods for removing the wall, as well as methods for disposing of the wall
  • Comply with all federal and District of Columbia standards

*Dade Moeller joined NV5 in May 2016 to integrate Dade Moeller’s safety & health, radiation protection, and environmental quality capabilities with NV5’s engineering, infrastructure, and program management resources. Our combined capabilities bring effective solutions to complex issues. Learn more.