On Subdividing Material Balances in Time and/or Space

The concept of material accountability is basic to nuclear materials safeguards. For a given space, called a material balance £rea (MBA) and a given period of time, called a material balance £eriod (MBP) , material accountability involves calculating a performance index, called either the material unaccounted _for (MUF) or the inventory (difference (ID). ~(The term MUF is~used in the balance of this paper). In a safeguards environment, the MUF is used to signal material diversion.