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The robot removes the sample from the clear transfer box, out of the two white sample containers, and transports it to the mock-up examination instrument. | Photo courtesy of Idaho National Lab.
Cheers erupted from an audience peering over plywood walls into a mock-up hot cell, the shielded environments scientists use to inspect spent nuclear fuel. The robot inside had successfully moved a mock radioactive sample from a transport box, out of its containers, into an examination instrument, and then back again. It was a satisfying ending to a nine-month-long project for four Idaho State University (ISU) mechanical and nuclear engineering students interning at Idaho National Laboratory (INL).
The goal of their project? To design a robotic system as a demonstration project for INL engineers. If the students’ feasibility study was successful, lab engineers could design a similar system to handle radioactive materials for analysis at INL’s Materials and Fuels Complex (MFC). The MFC is a testing center for advanced technologies associated with nuclear energy power systems, especially new types of fuel.
The intern team with their robot (to the right) inside of the mock-up cell. Left to right: Jerron Berrett, Larinda Nichols, mentor Kevin Croft, Sage Thibodeau and Cody Race.
The project needed to mimic the obstacles a real robotic system would face. For example, materials are ferried between facilities through a pneumatic transport system, which works much like the vacuum tubes at a bank drive-through. The robot needs 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 needs to reverse the process.
The system is required to be accurate within a 0.01-inch radius 99.99 percent of the time.
And because the robot is meant to work with radioactive samples, the equipment needs to operate in high radiation environments. The interns ensured their robot and mock-up area complied with all of these requirements, but it wasn’t easy.
The group researched nontraditional remote handling equipment. A trade study led it to choose a commercial robot. The team also explored the use of vision technologies, which would take the place of the shield windows typically used in similar nuclear facilities. INL provided the equipment needed for demonstrating both whole-area viewing and a 3-D vision system for close-up viewing of work.
After much research and trial and error, the team built the 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 to remotely 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 like this one would allow workers to complete maintenance and repairs without exposure to radiation. And it might even be cheaper.
The costs of the robots and vision systems are anticipated to be much less than those of current technologies. INL engineers still need to do more work to create equipment that is radiation resistant, sufficiently flexible, and robust enough to operate well inside the environments of typical hot cells. With a successful robotic demonstration to start, projects continuing this line of research -- whether completed by interns or INL staff -- hint at an exciting future.
The project was funded by INL. Group intern projects are one way INL works with students to enhance science, technology, engineering and math (STEM) education and build a talent pipeline for the next generation of INL employees. INL supports college internships, joint appointments, postdoctoral appointments, academic visitors, and international researcher exchanges, interactions that benefit both the laboratory and the universities. For more information on these opportunities, please visit the INL website.