Holdup Determinations Throughout the Life Cycle of a

The determination of holdup within a facility is a concern to operators,state authorities and to the International Atomic EnergyAgency (IAEA). However, the definition and the need for determinationand verification of this material are somewhat different.The IAEA considers any material within a process, whether inoperations or shut-down, as in-process holdup, or more preciselyas inventory. As for the different roles, the operator and state mustdetermine or estimate the amount of holdup in a facility and providean inventory declaration to the IAEA. The IAEA then mustverify that declaration. However, verification of in-process holdupcan be very challenging due to inaccessibility, inadequate measurementtechnology and the fact that the material may be flowingthrough the process. For this reason, the IAEA depends on verifieddesign features and operating parameters to provide addedassurance to all measurements and to provide reliable estimationswhere measurements are not possible. This paper outlines theneed for both design and material verification throughout the lifecycle of a facility.