Nuclear Fuel Cycle Simulation System (NFCSS) is a scenario based computer model for the estimation of nuclear fuel cycle material and service requirements. It has been developed by the IAEA. The model has been designed to estimate long-term fuel cycle requirements and actinide arisings.

The model uses simplified approaches to calculate the fuel cycle requirements. These simplified approaches make the code possible to estimate the long term fuel cycle service requirements for both open and closed fuel cycle strategies.

Below sketch illustrates the input and output parameters of the NFCSS.