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Nuclear Safeguards Education Portal
  

Material Balance Areas (MBAs)

 Inside the control room at the fuel fabrication facility, Westinghouse Electric Sweden in Västerås, Sweden, inspectors review the displayed schematics of the facility's operational flow. (source: Dean Calma/IAEA)
Inside the control room at the fuel fabrication facility, Westinghouse Electric Sweden in Västerås, Sweden, inspectors review the displayed schematics of the facility's operational flow. (source: Dean Calma/IAEA) 

An MBA is an area inside or outside of a facility such that the quantity of nuclear material in each transfer into or out of each MBA can be determined.  In addition, the physical inventory of nuclear material in each MBA can be determined when necessary.  The facility's design information is made available to the IAEA and is used to determine MBAs and to select Key Measurement Points (KMPs).  These MBAs are used to determine the nuclear material flows and inventories.

In determining MBAs, the IAEA uses the following criteria:

  • The size of the MBA should be related to the accuracy with which the material balance can be established
  • When determining the MBA, advantage should be taken of any opportunity to use Containment and Surveillance to help ensure the completeness of flow measurements and concentrate measurement efforts at KMPs.  This simplifies the application of safeguards
  • A number of MBAs in use at a facility may be combined into one MBA to be used for the Agency accounting purposes
  • If the State requests, a special MBA around a process step involving commercially sensitive information it may be established

A Key measurement point (KMP) is a location where nuclear material appears in such a form that it may be measured to determine material flow or inventory.  KMPs include the inputs and outputs (including measured discards) and storages in MBAs

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