Radiation Dose Calculations

 Calculate public and occupational radiation doses for a wide variety of facilities. 

MILDOS-AREA was developed for the US Nuclear Regulatory Commission to calculate potential doses to the public   surrounding uranium milling facilities. 

RESRAD, developed for the US Department of Energy, is a computer model designed to estimate radiation doses and risks from RESidual RADioactive materials.  RESRAD is the only code designated by DOE in Order 5400.5 for the evaluation of radioactively contaminated sites.

Example Dose Calculation Projects:

• For Cotter Corp. calculated potential doses to the public from operations of the Cotter Uranium Milling Facility in Canon City, CO.

• For a planned in situ uranium recovery facility in central Wyoming and an expanding facility in south Texas calculated potential doses to surrounding receptor areas and workers.

• Used RESRAD to calculate doses to individuals in a variety of settings, including members of the Navajo Tribe living in homes potentially contaminated by waste uranium ore.

• For Water Remediation Technology, developed an Excel-based system to calculate potential doses to municipal workers servicing well-head radium-removal water treatment tanks.

• For Cotter Corp., revised the occupational dose record-keeping system for their uranium milling facility in Canon City, CO.  

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    Historical Dose Reconstruction

In conjunction with a team from several companies, we have produced technical basis documents and site profiles to support historical dose reconstruction under the Energy Employees Occupational Illness Compensation Act (EEOICPA).  EEOICPA is intended to compensate worthy cancer victims who are former employees of the Atomic Energy Commission and its successor agencies and contractor organizations.

We have contributed to documentation of historic activities at the following sites: 

• Rocky Flats Plant.  The Rocky Flats plant was located approximately 20 miles northwest of Denver, Colorado.  It machined Pu-239 to manufacture classified triggers for nuclear weapons. Rocky Flats operated from the early 1950s until 1989 and was completely decommissioned and demolished by 2005.  We were involved in the successful defense of the RFP Special Exposure Cohort in 2007.

•   Weldon Spring Plant.  Mallinckrodt, Inc. operated the plant, located 25 miles west of St. Louis, Missouri, under a contract with the AEC from 1957 to 1966. The plant processed uranium ore concentrates to uranium tetrafluoride and uranium metal. Thorium ore, also a radioactive metal, was processed. The residues from the processing were disposed of in four large open pits.

• Argonne National Laboratory (ANL-E).   Argonne National Laboratory - East was established as the first national laboratory as a result of the Atomic Energy Act of 1946, which created the U.S. Atomic Energy Commission (AEC) and the national laboratory system. The University of Chicago has operated ANL-E since its creation. The research that ANL-E carried out in the early years as a national laboratory began under the university’s Metallurgical Laboratory, which built the first nuclear reactor, Chicago Pile 1 (CP-1), under the West Stands of the university’s Stagg Field. CP-1 successfully achieved the world’s first man-made nuclear chain reaction in 1942.
   

• Lake Ontario Ordnance Works (LOOW).  LOOW, located outside Buffalo, NY, was a storage site for residues of uranium ore processing.  A variety of waste materials were stored beginning in 1944 until the present.  Most of the higher level residues were removed from the site in the mid-1950s.  The site is currently under the purview of the US Army Corps of Engineers, which administers the Formerly Utilized Sites Remedial Action Project responsible for the site’s clean up.

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    Ecological and Human Risk Assessments

 Risk assessment is often required to establish the level of clean up of potentially contaminated sites.  Risk assessments may be conducted under guidance from the Environmental Protection Agency CERCLA guidance (http://www.epa.gov/superfund/health/contaminants/radiation/radrisk.htm)  or using other formats depending on the regulatory authority.  Examples of recent risk assessment projects include the following: 

·        Ecological and human health risk assessments of potentially contaminated water seeping into a publicly accessible stream near a former uranium milling facility in Washington. 

·        A human health risk assessment of uranium and heavy metal-bearing materials leaching from a former uranium concentration facility in Oklahoma.  The risk assessment was used to assist in decommissioning the site.  

·         Human health dose and risk assessments of public access to buildings near former uranium facilities in Utah and Colorado. 

• A review of potential radiation doses and dose limits to terrestrial biota resident on the Rocky Flats Environmental Technology Site. Compared existing dose limits in use at the site with approaches published for other facilities.

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    Field Surveys

In conjunction with TetraTech, Inc. we have conducted projects to conduct intensive gamma scanning of facilities to support licensing, to guide remedial action, and to verify that clean up standards are met.  

• Baseline gamma exposure measurements.  Gamma exposure scans provide important information for potential mine or mill owners prior to operations.  A comprehensive scan can meet the requirements of  NUREG 4.14 for Nuclear Regulatory Commission or agreement state licensing purposes.  Scanning also provides a priori evidence that contamination resident at the site was not the result of site operations and is a valuable record upon future site decommissioning.

• Estimate volume of contaminated soil for uranium milling facility.  In conjunction with TetraTech, Inc., we recently completed  a study to estimate the volume of  contaminated soil in excess of cleanup standards that will require removal.  The study consisted of developing a correlation between surface gamma exposure rate and Ra-226 concentration to estimate contaminated area. Subsurface sampling provided depth profiles of contamination.  The product of the two yielded the contaminated volume.

• Gamma surveys to guide assure cleanup standards are met.  Gamma surveys provide visual evidence to regulatory agencies that a site has, or has not, been adequately cleaned up.  A comprehensive survey, conducted while remedial action is accomplished protects the site owner/operator from future litigation.

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