Mechanical and nuclear engineering students from Idaho State University have designed a robotic system to handle radioactive nuclear fuel.

The students, interns at the Idaho National Laboratory (INL), completed the system as a demonstration project for INL engineers. Their design could provide the basis for INL scientists to build a device for handling radioactive materials for analysis at the lab's Materials and Fuels Complex.

The robot removes a sample from a clear transfer box and transports it to the mock-up examination instrument. Image credit: INL.The robot removes a sample from a clear transfer box and transports it to the mock-up examination instrument. Image credit: INL.Successfully completing the demonstration project required development of a robot that could overcome the obstacles that a real robotic system would face. For example, materials are ferried among INL facilities via a pneumatic transport system, which works much like the vacuum tubes at a bank drive-through. The robot is required to remotely load and unload radioactive samples from the multi-layered transport containers and deliver them to a sensitive scientific instrument for analysis, which includes opening its loading drawer. And then it has to reverse the process.

The system is required to be accurate within a 0.01-inch radius 99.99% of the time. Moreover, because the robot is meant to work with radioactive samples, the equipment must demonstrate operability in high-radiation environments.

The group researched nontraditional remote-handling equipment. A trade study led them to choose a commercial robot. The team also explored the use of vision technologies to take the place of the shield windows typically used in nuclear facilities. INL provided the equipment required for demonstrating both whole-area viewing and a 3D vision system for close-up viewing of work.

After much research and trial and error, the team built a mock-up robotic work cell. The key piece of equipment is the commercial 6-axis robot (plus gripper), with each axis having 360 degrees of motion. The team programmed the robot to complete all the necessary moves of the sample, returning it safely into the mock-up pneumatic transfer box. The robot arm features cameras that allow the team remote control using video monitoring screens, much like a video game.

This setup is different from the way scientists typically handle samples of radioactive material. Today, operators use mechanical manipulators viewed through shielded windows. This setup works well for the nuclear industry; however, the manipulators are expensive to design, purchase, install and maintain. A robotic system such as the students' design could allow workers to complete maintenance and repairs without exposure to radiation.

According to INL, the costs associated with the design's robots and vision systems are anticipated to be significantly less than those of current technologies. INL engineers now expect to do additional work to create equipment that is radiation resistant, sufficiently flexible and robust enough to operate well inside the environments of typical hot cells.

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