Sensitivity analyses of EPA's codes for assessing potential health risks from disposal of low-level wastes

The Environmental Protection Agency is developing generally applicable environmental standards for land disposal of low-level radioactive wastes. Comparing potential health risks to general populations and critical population groups from land disposal of LLW under a wide variety of disposal methods and hydrogeologic and climatic conditions is an important part of EPA's standards development process. EPA has developed the PRESTO family of risk assessment codes to compare these health risks. This paper presents a preliminary report on the sensitivity analysis phase of EPA's overall program to verify and validate the PRESTO models and codes. In the sensitivity analyses, input parameters related to waste form and composition, hydrogeologic and climatic conditions at the disposal site, and engineering barriers used were systematically varied to ensure that the models behave logically and to identify parameters having pronounced impacts on model output. Parameters tested, why tested, and summaries of qualitative results of tests of the PRESTO-EPA-POP and PRESTO-EPA-CPG codes are described