Researchers at MIT are working on small, egg-sized robots designed to dive into nuclear reactors and swim through underground pipes, checking for signs of corrosion. The underwater patrollers, equipped with cameras, are able to withstand a reactor’s extreme, radioactive environment, transmitting images via wireless in real time.
They devised a special valve for switching the direction of a flow with a tiny change in pressure and embedded a network of the Y-shaped valves within the hull, or “skin,” of the small, spherical robot, using 3-D printing to construct the network of valves, layer by layer
As the robot navigates a pipe system, the onboard camera takes images along the pipe’s interior. The researchers are working to equip the robot with wireless underwater communications, using laser optics to transmit images in real time across distances of up to 100 meters. The team is also working on an “eyeball” mechanism that would let the camera pan and tilt in place.
Reactor inspectors currently monitor these pipes remotely by running an electric current through them to find corroded sections or using ultrasonic waves to identify cracks, but the robot can get a much closer view with its on-board camera that takes photos of the pipe’s interior.
In June, The Associated Press released results from a yearlong investigation, revealing evidence of “unrelenting wear” in many of the oldest-running facilities in the United States. That study found that three-quarters of the country’s nuclear reactor sites have leaked radioactive tritium from buried piping that transports water to cool reactor vessels, often contaminating groundwater. According to a recent report by the U.S. Government Accountability Office, the industry has limited methods to monitor underground pipes for leaks.
“We have 104 reactors in this country,” says Harry Asada, the Ford Professor of Engineering in the Department of Mechanical Engineering and director of MIT’s d’Arbeloff Laboratory for Information Systems and Technology. “Fifty-two of them are 30 years or older, and we need immediate solutions to assure the safe operations of these reactors.”
Asada says one of the major challenges for safety inspectors is identifying corrosion in a reactor’s underground pipes. Currently, plant inspectors use indirect methods to monitor buried piping: generating a voltage gradient to identify areas where pipe coatings may have corroded, and using ultrasonic waves to screen lengths of pipe for cracks. The only direct monitoring requires digging out the pipes and visually inspecting them — a costly and time-intensive operation.
Source | Kurzweil AI