A review of research programs related to the behavior of plutonium in the environment

Abstract

Plutonium-fueled radioisotopic heat sources find application in a spectrum of space, terrestrial, and underseas applications to generate electrical power by thermoelectric or dynamic-cycle conversion. Such systems under postulated accident conditions could release radioactivity into the environment resulting in risks to the general population. The released radioactivity could be dispersed into various environmental media, such as air, soil, and water and interact with people through various exposure pathways leading to inhalation, ingestion, and external radiological doses and associated health effects. The authors developed short-term exposure (RISK II) and long-term exposure (RISK III) models for use in safety risk assessments of space missions utilizing plutonium-fueled electric power systems. To effectively use these models in risk assessments, representative input values must be selected for a spectrum of environmental transfer parameters that characterize the behavior of plutonium in the environment. The selection of appropriate transfer parameters to be used in a given analysis will depend on the accident scenarios to be modeled and the terrestrial and aquatic environments to be encountered. The authors reviewed the availability of plutonium in the environment. This report summarizes the research programs presently being conducted at six Department of Energy Laboratories and makes recommendations on areas where further research is needed to fill gaps in the data necessary for risk assessments