A sensor-based automation system for handling nuclear materials

An automated system is being developed for handling large payloads of radioactive nuclear materials in an analytical laboratory. The automation system performs unpacking and repacking of payloads from shipping and storage containers, and delivery of the payloads to the stations in the laboratory. The system uses machine vision and foradtorque sensing to provide sensor-based control of the automation system in order to enhance system safety, flexibility, and robustness, and achieve easy remote operation. The automation system also controls the operation of the laboratory measurement systems and the coordination of them with the robotic system. Particular attention has been given to system design features and analytical methods that provide an enhanced level of operational safety. Independent mechanical gripper interlock and tool release mechanisms were designed to prevent payload mishandling. An extensive Failure Modes and Effects Analysis of the automation system was developed as a safety design analysis tool. Introduction The Weigh And Leak check System (WALS) is being developed to provide an automated system for performing remote weighing and leak checking of radioactive nuclear materials at the Mason & Hanger Pantex Plant, a U.S. Department of Energy (DOE) facility. The materials, known as pits, are approximately the size and shape of a standard bowling ball. The system is required to perform the automated handling tasks in an attended, structured environment, with human operator interaction. These operations consist of unpacking and repacking the pits from a variety of sizes and types of containers used for storage and shipment, and transporting the pits to stations within an analytical measurement laboratory for automated and manual measurements and inspections. The weighing and leak checking operations are performed periodically to assure product integrity, safety, and inventory. Sandia is responsible for development and integration of the robotic and automated equipment for the packing, unpacking, and handling of pits, and for the sensor-based control system for WALS. Pantex is responsible for development of the weigh and leak check analytical instrumentation. A common application of automated handling systems is to relieve humans from hazardous material handling and heavy lifting . A primary goal of the WAT.3 system is to eliminate as much as possible the manual handling of radioactive materials. This achieves the DOE goals of reducing operator exposure to radiation and minimizing the possibilities for human mishandling. Some additional important benefits are also realized from this automation system. Once a procedure has been validated for a particular pit type, the automated control system ensures continued enforcement of the qualified procedure. Automated data entry methods reduce the need for operator interaction. These both add benefit to the system by reducing two of the largest sources of process error. Also, automated recording of product parameters and process results greatly enhances the quality assurance of the operation.