There are limits on the effort which may be expended in checking the physical inventory because of cost, personnel and equipment limitations especially the difficulty of the destruction analysis of large Pu inventories.
The objective of this paper is to select the optimum sample size for each measurement method to provide specified assurance of detection of some given goal amount.
One of the most important parameters are the errors of the inspector``s measurements for the purpose of verifying the data declared by the operator. The inspector Non Destructive Assay(NDA) measurement errors of the Reference facility that have been analyzed by HMERGE program have been varied within a range of less than 1% up to 5%. According to analysis of these errors terms, NDA measurements verification at the Reference facility keep enough capability to detect partial defects of IAEA criteria. Also, optimum sampling plan using binomial distribution, when target value to the nondetection probability is set equal to 10% for direct use material at the Reference facility, showed saving of 70 Person Day Inspections(PDIs) annually comparing with present PDIs.
In conclusion, application of appropriate NDA instruments and Containment/Surveillance(C/S) at the Pu inventory facility can reduce the PDIs within the satisfying of IAEA safeguards criteria.