[en] The United Stated Department of Energy began implementation of the ten year FRR SNF return policy in May, 1996. Seventeen months into the thirteen year return program, four shipments have been made, returning 863 assemblies of aluminum clad SNF to SRS. Five additional shipments containing over 1,200 assemblies are scheduled in fiscal year 1998. During negotiation of contracts with various reactor operators, it has become apparent that many facilities wish to delay the return of their SNF until the latter part of the program. This has raised concern on the part of the DOE that insufficient receipt capability will exist during the last three to five years of the program to ensure the return of all of the SNF. To help quantify this issue and ensure that it is addressed early in the program, a computer simulation model has been developed at SRS to facilitate the planning, scheduling, and analysis of SNF shipments to be received from offsite facilities. The simulation model, called OFFSHIP, greatly reduces the time and effort required to analyze the complex global transportation system that involves dozens of reactor facilities, multiple casks and fuel types, and time-dependent SNF inventories. OFFSHIP allows the user to input many variables including priorities, cask preferences, shipping date preferences, turnaround times, and regional groupings. User input is easily managed using a spreadsheet format and the output data is generated in a spreadsheet format to facilitate detailed analysis and prepare graphical results. The model was developed in Microsoft Visual Basic for Applications and runs native in Microsoft Excel. The receipt schedules produced by the model have been compared to schedules generated manually with consistent results. For the purposes of this presentation, four scenarios have been developed. The 'Base Case' accounts for those countries/facilities that DOE believes may not participate in the return program. The three additional scenarios look at the impacts of adding back different combinations of countries/facilities after a three year delay. The conclusions that can be formed based on the modeling of the offsite receipts are quite obvious. Shipments should be maximized early in the program to ensure all material is returned within the thirteen year program. Cask availability is adequate but cask utilization must be maximized. Cask turnaround time is critical to ensuring all material is returned within the program time frame. SRS has adequate storage capacity for all material planned for return. It is important to update SRS's information on SNF inventories, cask availability, and facility preferences frequently to ensure receipt schedules are accurate and meet program objectives. (author)