Much like the fictional cleaning robot currently packing movie theaters, robots are being used to clean humanity’s worst messes. At Hanford Nuclear Reservation in Washington State, where plutonium for Cold War nukes was made, robots are on the front line of the cleanup effort. The job is to empty about 150 basketball-court-sized tanks of nuclear and chemical waste before their contents reach the Columbia River. Exposure to the material would kill a human within moments. Sounds like a job for robots. Since there won’t be any attention from Pixar, we again salute the little guys going a bit beyond the iRobot Looj in their daring damage control.
The only way in or out of most of the tanks is through foot-wide pipes in their roofs, so engineers at Hanford use this robotic dozer, which opens into a string of pieces that fit through the inlets. Once inside, Foldtrack reassembles like a toy Transformer. The robot uses a 3000 psi water stream to blast at sludge from up to 20 ft. away. A remote driver directs the robot as it uses a dozer blade to push the waste toward a pump for transfer to safer, double-shelled tanks. Once its job is done, the $500,000 robot is sealed, forever, in the empty tank.
This robot may not look like much but a glorified fire hose, but it’s hiding a valuable secret. The Salt Mantis can shoot water at up to 35,000 psi to blast tough toxic salts that build up inside nuclear waste tanks. The water jets from a tiny orifice made of gems, including sapphires—the only material that can (literally) stand up to the pressure. The robot’s crosslike body scissors together to squeeze into the narrow opening of the sludge tanks. While inside it moves around by remote control, since onboard electronics would fry from the exposure to radiation.
Off-Riser Sampling System, aka "Possum"
It used to be that human cleaners had to just guess if the radioactive area they were cleansing was, indeed, clean. Like a faithful retriever, the Possum rolls to the far, dark reaches of waste tanks, scooping up samples with its bulldozerlike blade so engineers can tell exactly what, and how much, is left inside. The Possum comes equipped with a camera so operators can locate target waste and control the device.
Tandem Synthetic Aperture Focusing Technique (T-SAFT), aka "Tank Crawler"
Hanford relies on 28 double-shell radioactive waste storage tanks to contain its sludge. This bot creeps on magnetic feet to look for cracks or corrosion. Each robotic foot can demagnetize to step, then remagnetize to affix itself to the wall. It scans the tanks with ultrasonic and electrical conductivity sensors. The results have been encouraging—cleanup crews found that all the tanks are holding up well. And that’s good news, because the sludge the other robots are removing is being relocated into vessels like these.
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