Nuclear Fuel Cycle and Materials

Nuclear Fuel Cycle Related Databases

Nuclear Fuel Cycle Simulation System (NFCSS)

Contact: Harikrishnan TULSIDAS

Nuclear Fuel Cycle Simulation System (NFCSS, formerly known as VISTA) is a scenario based computer model for the estimation of fuel cycle material and service requirements, 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, makeing it possible to estimate the long term fuel cycle service requirements for both open and closed cycle fuel cycle strategy.

NFCSS an online application that can be accessed at The web site provides detailed description of the simulation system, an example scenario with results and a simple calculation tool which can be used to calculate annual material flow in a selected nuclear fuel cycle option.

Users should have a free IAEA Nucleus account to use the system.

Description of the Simulation System

NFCSS code takes strategy parameters, fuel parameters, control parameters as input and gives some fuel cycle service requirements and spent fuel arisings, plutonium arisings as result.

Input parameters are categorized into three groups:

  • Strategy Parameters: nuclear capacity variants, reprocessing-recycling strategies, reactor type mixtures and load factors for each type of reactor. The reactor types taken into consideration are PWR, BWR, PHWR, AGC, GCR, RBMK and WWER. Load factors are given as aggregated values for each type and not individual values for each reactor in the world.

  • Fuel Parameters: average discharge burnup, average initial enrichment, average tail assay on an annual basis and aggregated for each reactor type.

  • Control Parameters: share of MOX fuel in reactor fuel, lead and lag times for different processes and the number of spent fuel reprocessing cycles.

Outputs are:

  • Natural uranium, conversion and enrichment service requirements.

  • Fresh fuel requirements and spent fuel arisings.

  • Total plutonium arisings and separated plutonium utilization.

  • Reprocessing and MOX fuel fabrication service requirements.

Access NFCSS online at (

Rate this page:
Follow the IAEA:        
Responsible: Webmaster | 14 Jun, 2016