Automated Inspection of Criticality Control Overpacks for Surplus Plutonium Disposition

To reduce the amount of weapons-grade nuclear waste present in South Carolina, the Department of Energy (DOE) started an initiative to dilute and dispose of the state’s surplus plutonium. This process involves downblending high-level radioactive waste with inert material, to be disposed of at the Waste Isolation Pilot Plant (WIPP). This disposition process will take place over the next 30 years, and as such, will process upwards of 120,000 Criticality Control Overpack (CCO) containers. Due to the high volume of CCOs being inspected and the long lifespan of the project, the Savannah River Site (SRS) tasked Savannah River National Laboratory (SRNL) with automating segments of the process to reduce worker dosage and remove overly strenuous and monotonous tasks from skilled workers. The primary objective of this project is to determine the feasibility of automation for DOE Surplus Plutonium Disposition (SPD) packaging applications. SRNL chose the receipt and inspection of incoming CCO storage drums for the downblended waste as a proof-of-concept for the benefits of automation. Currently, SRS receives and manually inspects CCOs, requiring approximately six operators to unpack the CCO, ensuring both the CCO and Criticality Control Container (CCC) are within specification and void of security concerns. The current manual inspection operations are incapable of matching the planned increased rate of throughput of CCOs.   SRNL has developed and programmed a robotic work cell to inspect CCOs. An automated guided vehicle (AGV) delivers CCOs to the inspection work cell with a six-axis robotic arm which uses various custom designed end-of-arm tooling (EOAT) to unpack and inspect the CCOs. The unpacking process involves the removal of the lid, dunnage, and CCC from the CCO. After the automated inspection, the robot repackages the CCO and applies a tamper indicating device (TID) with a unique serial number. Serial numbers of the CCO, CCC, and TID, external scans, and images are collected into a data package for each individual CCO. This information is compiled to populate a material tracking system with the relevant information.   Integrated testing and installation of the system is underway. Recent improvements have been made to the inspection takt time, CCO center detection for AGV picking, drum ring gripper, CCC gripper, automated drill mounting, the TID application tool, and the TID. The changes to the work cell and tooling make the system more robust, reliable, and deployable. The reduced takt time also allows for this system to meet the projected maximum throughput of CCOs throughout the disposition process at SRS.   This system is an important first step to maximizing the automation of SPD. The automated inspection of nuclear storage containers is not limited to CCOs and can be applied to most packaging solutions. The same technology used in this inspection process will be used in the future to load CCOs with downblended plutonium produced in the SPD process. These automation systems have the ability to make a large impact across the DOE and nuclear industry as a whole with the overarching goal being to protect the workforce by reducing dose.