INTRODUCTION

In support of the U.S. Department of Energy (DOE) Order establishing residual radioactive material guidelines (DOE Order 5400.5), Argonne National Laboratory (ANL) developed a computer program called RESRAD (Gilbert et al. 1989). The models used by ANL to develop RESRAD were initially developed as part of a DOE-wide effort that began in the early 1980s and involved most of the national laboratories and DOE program offices. The DOE and other agencies and their contractors use the RESRAD program and its manual to derive cleanup criteria and dose calculations. Since its first release in June 1989, many new features and pathways have been added to the RESRAD code. The DOE Offices of Environmental Guidance and Environmental Restoration provide periodic guidance regarding any significant changes to the code and manual. The purpose of this handbook is to give RESRAD users guidance on gathering, evaluating, and selecting input data for the RESRAD code.

The RESRAD code is a user-friendly, multiple pathways analysis code designed to be run on IBM-compatible personal computers. It was developed for use by radiological health physicists and environmental engineers for the calculation of radiation dose and risk resulting from exposure to residual radioactive material.

A sensitivity analysis of RESRAD parameters was conducted at ANL in 1991; the results for a generic run are presented in RESRAD Parameter Sensitivity Analysis (Cheng et al. 1991). In general, parameters associated with the cover material or the contaminated zone influence results more than parameters associated with the unsaturated or saturated zone before the breakthrough time of the groundwater contamination.⁽²⁾ The influence of these parameters changes, however, after the breakthrough time. The sensitivities of parameters involved in the leaching process have opposite effects on the total dose before and after the rise time.⁽³⁾

A built-in sensitivity analysis capability has been added to the RESRAD code. This capability gives users an easy way of studying RESRAD parameter sensitivity. Users are referred to the revised RESRAD Manual for Implementing Residual Radioactive Material Guidelines (Yu et al. 1993) and RESRAD Parameter Sensitivity Analysis (Cheng et al. 1991) for a description of and guidance on using this enhanced feature of the RESRAD code.

Fifty-one parameters are discussed in this handbook. Table 1.1 lists the RESRAD input parameters in the order of the RESRAD input screens and the sections of this hand- book in which the parameters are discussed. For parameters not discussed in this handbook, users are referred to other sources (Table 1.1). Table 1.2 lists the applicable pathways and the data input screen locations for RESRAD input parameters.

This handbook provides the definition, typical range, default value used in RESRAD, relation to other parameters, and measurement methodology for most of the measurable parameters. Table 1.3 lists the default values and the lower and upper bounds set in the RESRAD code for each parameter used in the code. The intent of this handbook is to provide users with a better understanding of each input parameter in terms of its typical range, variation, and use in the RESRAD code.

The default parameter values listed in Table 1.3 have been carefully selected and are realistic, although conservative, parameter values. (In most cases, use of these values will not result in underestimation of the dose or risk.) Site-specific parameters should always be used whenever possible. Therefore, use of default values that significantly overestimate the dose or risk for a particular site is discouraged.