When uranium enrichment plants are shut down, you can't just take the wrecking ball to them – you first have to remove and dispose of any still-radioactive piping. Scientists at Carnegie Mellon University have developed a robot that should make finding those bits of problematic pipe much easier.

Known as RadPiper, the cylindrical-bodied tetherless robot is manually placed inside straight sections of pipe, then proceeds to crawl through them on a set of flexible tracks. It uses a LiDAR unit (Light Detection and Ranging) and a fisheye video camera to identify obstructions such as closed valves, and once it reaches the end of each section, it automatically reverses and returns to its starting point.

To perform its inspection, the robot utilizes a sodium iodide radiation sensor to detect uranium deposits on the inside of the pipe. Lead radiation-shielding discs on either side of that sensor allow the robot to inspect the pipe in isolated one-foot (0.3-m) segments, blocking gamma rays that are being emitted from deposits located farther up or down the pipe.

When a deposit is detected, the robot alerts human workers to its location. They can then remove that segment of pipe and carefully dispose of it. Ultimately, all that will be left is uranium-free piping, which can be demolished along with the rest of the facility.

Ordinarily, in order to locate such deposits, people wearing protective suits have to perform external radiation measurements by hand. Not only does this reportedly result in less accurate readings than those obtained by the robot, but it also poses a risk to the workers, plus it requires them to use lifts or scaffolding to reach elevated pipes.

In May, two production prototype RadPipers will be used for pipe-inspection at the US Department of Energy (DOE)'s former uranium enrichment plant in Piketon, Ohio. The facility began operations in 1954, closed its doors in 2000, and is now awaiting demolition. Although workers have already almost finished with the pipes in one of its process buildings, there is still a lot of work to do, and it is estimated that use of the robots could potentially save tens of millions of dollars in labor costs.

"With more than 15 miles [24 km] of piping to be characterized in the next process building, there is a need to seek a smarter method," says Rodrigo V. Rimando, Jr., director of technology development for DOE's Office of Environmental Management. "We anticipate a labor savings on the order of an eight-to-one ratio for the piping accomplished by RadPiper."

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