Inside Unmanned Systems

AUG-SEP 2018

Inside Unmanned Systems provides actionable business intelligence to decision-makers and influencers operating within the global UAS community. Features include analysis of key technologies, policy/regulatory developments and new product design.

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AIR HAZARD LOCATION 60   August/September 2018 unmanned systems inside but each has a different number of neutrons—for instance, uranium-235 has 143 neutrons, while uranium-238 has 146.) The kind of nuclear chain reactions that both nuclear reactors and nuclear weapons depend on are possible with uranium-235 but not with ura- nium-238. During the Cold War, uranium enrich- ment plants often forced a gas of uranium-laden molecules through membranes that could separate the lighter uranium-235 from the heavier ura- nium-238, resulting in "enriched" uranium with high concentrations of uranium-235. This process typically left deposits of radioactive waste clinging to the insides of miles of the plants' "process pipes." "These deposits almost look like a thin layer of paint inside the piping," said William "Red" Whittaker, a robotics professor and director of the Field Robotics Center at Carnegie Mellon University in Pittsburgh. "This material is de- posited during a chemical reaction with the ura- nium-laden gas with water or something else that would provide oxygen." Whittaker and his colleagues have now built an autonomous robot called RadPiper to help detect this hazardous nuclear waste at the Department of Energ y's 3,778-acre Portsmouth Gaseous Diffusion Enrichment Facility in Piketon, Ohio. Shuttered since 2000, this plant began opera- tions in 1954, and with 10.6 million square feet of f loor space, it was the Department of Energy's largest roofed facility. Three large buildings con- tain enrichment process equipment that spans an areas the size of 158 football fields and contains more than 75 miles of process pipe. Locating the nuclear waste throughout the huge facility is a herculean but essential task before the Department of Energy can decon- taminate, decommission and demolish it. In the Portsmouth plant's first process building alone, human crews performed more than 1.4 million measurements of processing piping and compo- nents manually over the past three years before they could declare the building "cold and dark." The next process building has more than 15 miles of piping that needs scanning, which robots could help with immensely, Rimando said. Scientists at Carnegie Mellon University were paid $1.4 million to build RadPiper as part of what the university calls the Pipe Crawling Activity Measurement System. The researchers developed the robot in close collaboration with Fluor-BWXT Portsmouth, the contractor that the federal government hired to decommission the Portsmouth facility. Whittaker has a great deal of experience with ro- bots in nuclear facilities, including the design and construction of robots that helped gather data and remove debris after the partial meltdown at the Three Mile Island reactor building in Pennsylvania in 1979. He and his colleagues also developed ro- bots to help with inspections in the aftermath of the Chernobyl disaster in Ukraine in 1986. The conventional technique for identifying hid- den deposits in process pipes involves people with handheld radiation detectors scanning process pipes from the outside in search of the gamma rays from radioactive isotopes. However, "since you're measuring from the outside, those gamma rays can be attenuated by the pipes themselves," Rimando said. This method is time-consuming and labor- intensive. "You have to hold the detector outside the pipe for at least 30 seconds before you move a foot or so further down to measure the next seg- ment," Rimando said. "And many of these pipes are overhead, and normally need a scissor lift or some other platform to access, and as you move down a pipe, you'll need to move the scissor lift to a new location as well. Logistically, there may also be issues getting a lift in certain places in a building, and the stanchions and brackets hold- ing up the pipes can be very difficult to maneuver around as well." " FOR EVERY EIGHT HOURS OF CONDUCTING SURVEYS WITH HANDHELD EQUIPMENT, RADPIPER CAN DO IT IN AN HOUR, AND THAT EIGHT-TO-ONE RATIO IS LIKELY AN UNDERESTIMATE." Rodrigo Rimando, director of technology development, U.S. Department of Energy, Office of Environmental Management RADIION CLEANUP

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