NRC RESPONSE TO SIGNIFICANT INVENTORY DIFFERENCES

I am happy to be with you today to discuss the subject of NRC's response to significant Inventory Differences (ID). Before I begin, I want to make it clear that the licensee has the primary and immediate responsibility to respond to ID. Response by the NRC is initiated as a complement to efforts by the licensee to investigate the possibility of a diversion. Now getting to the subject at hand, let me first define a general situation which would require response by the NRC as well as by the licensed facility. For purposes of discussion, we will consider a complex highly enriched uranium (HEU) fuel processing facility. This facility might possess about one thousand kilograms of HEU located in storage items, intermediate products, process hold-up, scrap materials, and wastes. During a sixty day material balance period between physical inventories, the plant might in some way process or work on 40-60% of its inventory. Let us assume a plant \"throughput\" (which the NRC defines as the greater of the amount either added to or removed from the process) of 500 kg for the sixty day period. In accordance with NRC requirements, the plant has determined a limit-of-error for the ID to be approximately 2 kg -- a value which satisfies our requirement that uncertainties in the plant's total measurement system (LEID) be less than one-half of one percent of throughput.