in-Process inventory Estimation in a Reprocessing Facility for Near-Real-Time Accounting

A modern large scale reprocessing facility (1500 MTU/yr) presents a unique challenge to meet current safeguards objectives for timely detection of material losses. For material accounting to be responsive at these throughput rates, frequent material balance closures are required. The limiting factors have been physical costs, downtime and operability constraints of inventories for frequent-material balance closures. An In-Process Inventory Technique (IPI) has been developed and tested at the Barnwell Nuclear Fuel Plant (BNFP) to provide frequent inventories without cost or ins t rusiveness to plant operability. A computerized measurement system makes available process measurements and process control analytical information. These data are processed to determine the process inventory. The calculation routines use routinely available process control measurements and sample results. The technique requires no shutdown, no special preparations, and no special measurements, or samples. With this technique, hourly inventory frequencies and material balance closures have been achieved during demonstration runs in the 1500 MTU/yr at BNFP. Results show sensitivities of 2 to 5% of the normal process inventory are achievable during normal operations. Recent improvements in data handling routines indicate the technique can be sensitive during transient process conditions as well.