MIE.40 – Using Robotics to Remotely Handle A Radioactive Container for Fermilab National Accelerator Laboratory

• David Cedillo
• Sebastian De La Torre
• Patrick Mika
• Eduardo Orozco Gallegos
• Nisarg Patel
• Tyler Tischer

At Fermilab National Accelerator Laboratory, carbon graphite target sheets are exposed to high-energy proton beams in order to release secondary and tertiary particles from the target. One of the particle types of interest are neutrino particles. For these particles to be further studied, they must be moved to a controlled setting called a “hot cell.” However, after the target sheets are struck by the proton beam, the material starts experiencing radioactive decay and becomes a source of radiation. This becomes an issue as transporting these materials out from their radiation-safe containers and into shielded research environments exposes individuals to harmful radiation which can put researchers at risk. Such exposure to gamma radiation has been known to negatively affect the biological function of DNA in individuals. As a result, Fermilab requires of this team a method to remotely remove the lid from a radiation-safe container and transport an inner radioactive container to a hot cell room. The goal is to minimize radiation exposure to Fermilab staff, and so the proposed solution is a robotic device that can operate without staff members present in the room. Multiple design alternatives were put forth to solve this problem. One design was a mobile floor crane with four wheels and a hook end-effector to lift the container lid and inner radioactive canister. Another was an overhead crane with a three-finger gripper and a linear actuator arm, like what would be seen in a claw machine game. Another was a mobile floor crane with tank treads and a hook end-effector. A wall-mounted crane with a linear actuator for vertical displacement and a hook end-effector was ultimately chosen. The premise of a wall-mounted crane was chosen based on preference by the Fermilab staff. Most other parts of the robotic crane were chosen based on elimination of alternatives that were infeasible due to characteristics such as unreliable performance, loading limitations, physical makeup that created incompatible interaction with the materials, among other things. The microcontrollers used to manipulate the robot and placed cameras are vulnerable to damage from radiation exposure. This problem was circumvented by placing the microcontrollers into an adjacent room and connecting it to the robotic components via a small hole in the wall and by regularly replacing the cameras, with Fermilab’s approval. The same hole in the wall also allows the robot to be powered and controlled via direct wiring. The final design was validated by creating a small-scale prototype and performing motion study simulations to prove that the mechanical motion and makeup were viable, and ANSYS simulations were performed to ensure that all relevant loading can be withstood. The final design is successful because it can verifiably perform the required movements and lifts, it can withstand the effects of present radiation, and it can be operated without a Fermilab member in the room, thus preventing human radiation exposure.