[en] The primary goal of the advanced isotope separation (AIS) program is to develop a uranium enrichment technology that will produce enriched uranium at a cost of less than $40 per separative work unit (SWU) (end of FY 1981 dollars) in the mid 1990s. There are three potential applications for an AIS process, all of which significantly lower the cost of uranium enrichment. This document compares the environmental impacts of the three alternative AIS technologies. The primary purpose of the environmental assessment is to provide the environmental impact perspective to the Process Evaluation Board (PEB) that will be responsible for recommending one of the AIS technologies for the demonstration phase of research and development