This report evaluates how the economic environment (i.e., discount rate, inflation rate, escalation rate) can impact previously estimated differences in lifecycle costs between an integrated waste management system with an interim storage facility (ISF) and a similar system without an ISF. The costs analyzed in this report are based on the document entitled Cost Implications of an Interim Storage Facility in the Waste Management System, a systems study comparing the “constant dollar” future lifecycle costs of spent nuclear fuel (SNF) management system scenarios.