DESIGN, DEVELOPMENT AND TESTING OF AN AUTOMATED MEASUREMENT SYSTEM FOR THE ASSAY OF PLUTONIUM IN 3013 CONTAINERS

Plutonium in a variety of forms stored in 3013 containers is one of two main i nput materials to the MOX f acility being c onstructed at the Savannah River Site by Shaw AREVA MOX Services , LLC . The purpose of the MOX facility is to fabricate Mixed Oxide (MOX) reactor fuel from plutonium and uranium derived from decommissioned nuclear weapons. This paper describes the design, development and testing of an automated and integrated non - destructive assay (NDA) system consisting of a Gantry R obot crane, a sample weigh station, two gamma ray isotopic ratio spectrometry instruments, four calorimeter temperature pre - conditioners and four calorimeters. The purpose of the system is to assay and thus characterise all of the plutonium, which is an input to the fuel fabrication process. At the highest level the MOX facility Normal PLC (NPLC) system controls the movement of a sample by di recting the Gantry R obot crane to move 3013 containers from an input conveyor to the various conditioning and measurement stations and then into storage positions. After the weight measurement , the 3013 - container s are moved to temporary storage or one of the temperature pre - conditioning stations. The second stage of the measurement process is to load the 3013 - container into one of the isothermal calorimeters. Following the completion of a cal orimeter measurement of the container thermal power, the G a ntr y R obot crane moves the container to one of the plutonium gamma ray spectrometers to determine the plutonium isotopic ratios. Measurement data from the assay stations is combined in a Measurement Control Computer (MCC) and the assay result for each 3013 - c ontainer of plutonium is transmitted to the MOX facility Normal PLC system. The paper describes the design and testing of the Gantry R obot crane with bar code reading and including the gripper designed to handle 3013 - container with a misaligned lifting f eature. Novel multimode calorimeters , thermal pre - conditioners and shielded plutonium isotopic ratio gamma ray spectrometers designed to measure fissile material in 3013 containers are described .