Engineers at Massachusetts Institute of Technology have developed a small robotic device to inspect underground pipes for corrosion at nuclear reactors. A prototype of the remote-controlled device was presented in May at the 2011 IEEE International Conference on Robotics and Automation.
The device, about the size of an egg and with a spherical shape, was designed by a team led by mechanical engineering professor Harry Asada. Groups of these devices are expected to dive into nuclear reactors and swim through underground pipes, checking for signs of corrosion. The spheres are equipped with cameras, and expected to withstand a reactor’s extreme, radioactive environment during their lifetimes.
Asada and colleagues gave the device a smooth spherical shape, with no propellers or rudders, or any obvious mechanism on its surface to power the robot through an underwater environment. A robot outfitted with external thrusters or propellers could get tangled in a reactor’s mechanisms, which would then become more of a hindrance than help to the reactor operators.
The robot has a propulsion system that can harness the force of water rushing through a reactor. It has a valve for switching the direction of a flow with a tiny change in pressure and embedded in a network of the Y-shaped valves in the robot’s hull. The robot’s operator can shoot water through specific valves, creating a jet stream that propels the robot in the opposite direction.
The current version of the robot has a camera to shoot images, which can be retrieved upon completion of the mission. Asada’s team, however, is working on a wireless configuration that will allow the camera to transmit real-time images with laser optics up to 100 meters. The next version of the device is also expected to give the camera pan and tilt capabilities.
While the troubles at Japan’s Fukushima Daiichi nuclear power plant have generated worldwide attention, the state of older American nuclear plants are also a cause for concern. In a report issued in June, the U.S. Government Accountability Office noted that radioactive leaks from underground pipes posed a threat to groundwater in the plants’ vicinity. The GAO recommended that the Nuclear Regulatory Commission keep “abreast of ongoing industry research to develop technologies for structural integrity tests and, when they become feasible, analyze costs to licensees of implementing these tests compared with the likely benefits to public health and safety.”
Asada and colleagues designed the robots to meet these kind of cost-effectiveness criteria. The devices are expected to be relatively inexpensive, and used only a few times before wearing out from the exposure to radioactivity.
Read more: Institute Developing Autonomous Underwater Robots
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