What is RESRAD and why should you care?
Since the Manhattan Project in World War II first launched the large scale nuclear enterprise in the United States, large amounts of radioactive waste have been generated by both civilian and military uses of nuclear power. These wastes span a wide range of hazards from high-level wastes, such as spent reactor fuel and liquid wastes generated by the chemical separation of plutonium, to lightly contaminated soils, clothing, and building materials. In areas where these wastes will be disposed of, or areas where contamination will not be fully remediated during cleanup, the most important question to ask from the standpoint of protecting human health is how much of the radiation left in the ground will eventually reach people and thus be able to cause them harm. The closely related question of what impact the radioactive materials will have on the larger ecosystem, including plants and other animals, is outside the scope of the present work.
Determining how humans may be affected by radioactive waste or other types of contaminants buried in the soil is a significant challenge and requires a great deal to be known about the properties of the site and how it may be used by humans in the future. For long lived radionuclides, it may be necessary to project certain assumptions about the site and its uses into the distant future, adding to the complexity of this challenge.
Given that many of the necessary calculations are clearly quite complex, dose assessments are best done on a computer. It is in this light that we introduce RESRAD, the focus of this manual. In an effort to create a single tool that could carry out the steps described above, RESRAD (short for RESidual RADioactivity), a computer based simulation program, was developed by the Environmental Assessment Division of Argonne National Laboratory and first released in 1989.
The RESRAD program allows the user to specify many features of a site and to select the types of exposure pathways that will be important. It can then use the information provided by the user to predict the annual dose received by an individual at anytime over the next 100,000 years. Specifically, the exposure pathways considered by RESRAD include
- External radiation from contaminants in the soil.
- Inhalation of radon and its daughters, inhalation of other gaseous radionuclides like carbon-14 (C-14), and inhalation of contaminated dirt and dust that becomes resuspended in the air.
- Ingestion of plants such as vegetables, grains, and fruits, ingestion of meat and milk from cattle, ingestion of fish and other aquatic foods from an onsite pond, ingestion of contaminated soil, and drinking contaminated water from an onsite well or from an onsite pond.