A Benchmark Comparison of EPA Computer Models for Demonstrating Compliance to the Regulatory Effluent Dose Constraint at a Radioactive Waste Processing Facility
Date of Award
Master of Science
Laurence F. Miller
Ronald R. Pevey, Gloria T. Mei
The U.S. Environmental Protection Agency (EPA) and the Nuclear Regulatory Commission (NRC), or NRC agreement states, establish radiation dose limits to members of the public from airborne radionuclide emissions released from facilities licensed to use and/or handle radioactive material. These regulations specify that the licensee ensure that the individual member of the public likely to receive the highest dose shall not be expected to receive a total effective dose equivalent (EDE) in excess of 10 mrem (0.1 mSv) per year. Doses to members of the public from airborne effluents are evaluated using EPA-approved computer programs, such as COMPLY or CAP88. These are screening/compliance computer software programs, which make conservative modeling assumptions and require simple input data. COMPLY code, developed in 1989, is an extension of the National Council on Radiation Protection (NCRP) screening levels which are based on documented and well-known radiological assessment principles that combine environmental transport mechanisms, exposure pathways, and dosimetry components. The EPA no longer provides technical or administrative support for the COMPLY code, although it is still available for download and is still used by licensees. EPA’s CAP88-PC program was developed to demonstrate compliance with the Clean Air Act as applied to radionuclide emissions from licensed facilities outlined in 40 CFR 61 Subpart H (Rad-NESHAP). CAP88-PC is now the only code for effluent emissions that the EPA supports and routinely updates in concert with model improvements. The purpose of this benchmark study was to determine if there is a significant difference between dose estimates obtained for a radioactive waste processing facility’s annual radionuclide effluents using COMPLY-Level 4 and CAP88-PC software codes. Based on the comparison of the code results for one facility and its isotope emissions for the years 2004 to 2012, there was no significant difference found in the results. However, CAP88-PC incorporates the latest science and is easier to use than COMPLY. Since the EPA allows the use of both codes for demonstrating compliance, it is ultimately up to the user on which to select.
McCroskey, Debra Ann, "A Benchmark Comparison of EPA Computer Models for Demonstrating Compliance to the Regulatory Effluent Dose Constraint at a Radioactive Waste Processing Facility. " Master's Thesis, University of Tennessee, 2014.