Nuke Bot To The Rescue? CMU Robot To Detect Nuclear Waste At Government Facility

Apr 2, 2018

Cylindrical in shape, about 3 feet long and undeterred by radioactive waste, RadPiper is a robot developed by a team of scientists at Carnegie Mellon University's Robotics Institute to detect traces of nuclear material at a U.S. Department of Energy facility in Piketon, Ohio. 

It's part of the CMU Pipe Crawling Activity Measurement System, and the team hopes it will revolutionize efficiency and safety in the DOE's nuclear cleanup program, which anticipates at least 50 years of work ahead.

The Piketon plant was decommissioned in 2000, after 46 years of enriching weapons-grade uranium for Cold War-era government projects. 

A RadPiper prototype captured this image inside the Portsmouth Gaseous Diffusion Enrichment Facility in Piketon, Ohio. Yellow uranium deposit is peeling away from the metal pipe.
Credit RadPiper / Carnegie Mellon University Robotics Institute

"At the time that it was operating, it was using as much electricity as Manhattan just to operate the uranium enrichment plant," said Heather Jones, the senior project scientist who leads the RadPiper team's two dozen mechanical and software engineers. "There are more efficient ways to do this now. So if we needed to enrich a bunch of uranium, which hopefully we don't right now, this wouldn't be the way to do it."

Now the federal government wants to demolish the building and make way for a new industrial park. But before that can happen, every square inch of the facility must be inspected for radioactive material and decontaminated. 

Otherwise the demolition would present a significant safety hazard, Jones said, exposing workers to unacceptable amounts of radiation or even an explosion.

"If there's too much uranium-235 in one location, there is a concern that at some point that could go critical. Something could explode," Jones explained. "But for regulatory reasons, it's required that they measure every foot of pipe."

More than 75 miles of uranium enrichment pipes span three large buildings, or the size of 158 football fields, according to a CMU release.

Before CMU scientists devised RadPiper, the inspection and decontamination process of deconstructing a former enrichment plant was all done by hand. Human crews used motorized scissor lifts to reach pipes 12 to 15 feet in the air and took radiation measurements every few feet.

An expanded view of RadPiper shows its robotic components.
Credit Siri Maley / Carnegie Mellon University

That process was time-intensive and costly, Jones said. 

In the past three years, humans have performed over 1.4 million measurements at the Piketon facility, inch-by-inch along the pipes. Analyzing those measurements, which are also written by hand, can take months or years, CMU reported, and associated labor costs can reach $50 million.

RadPiper would change all that. The Department of Energy paid CMU $1.4 million to develop a pair of the wireless robots. Together, the two would tackle at least 15 miles of remaining unchecked pipe in the facility. Unlike the human process, RadPiper would need no breaks.

RadPiper rolls through the pipe on treaded tracks at a rate of 10 feet per minute. It features a disc-collimated sensing instrument, which "uses a standard sodium iodide sensor to count gamma rays," according to CMU. That technology isn't new, said Jones, but its application is. The sensor is between two large, lead discs which allows RadPiper to surveil uranium deposits in its environment one foot of pipe at a time. If a portion of pipe is found to be contaminated by uranium, that section is cut out and properly disposed of.

It can't turn corners (and there are many throughout the plant), but the robot is equipped with fisheye cameras that can detect obstructions like closed valves or drop-offs. When its route is complete, RadPiper automatically returns to the launch point. 

The team scours southwestern Pennsylvania and surrounding states for pipes that mimic the ones found in uranium enrichment facilities.
Credit Adelina Lancianese / 90.5 WESA

And RadPiper is constantly communicating with its laptop-bearing humans below. The data analysis that once took months or years can now be completed in a matter of minutes or hours, Jones said.  

The robotics team is in the final development stages of RadPiper and hopes the robots will be ready to roll at the Piketon facility by May or June. They anticipate using RadPiper technology at a similar uranium enrichment plant in Paducah, Ky., which is at least a year behind Piketon in the demolition process.

"During the World War II era and the Cold War era, there was [this mindset] of we have to develop as quickly as possible, and basically they made a big mess," Jones said of the government's nuclear projects. "And now we're stuck with trying to clean it up. And I think robotics is going to be an important part of that."

The Robotics Institute has also received interest from potential clients in Canada and Japan, as well as from entities that would like to adapt RadPiper technology for other uses, like crawling through sewer pipes. Jones said any further contracts will be handled by a company spun-off from the university, which governs research and development but not continued sales.

"I hope it makes a big impact on worker safety and on the efficiency with which they can decommission this facility," Jones said. "And I hope it can go out into other facilities and do the same job, or more jobs."

When scientists finally situate RadPiper into its Piketon launchpad, it will be a bittersweet goodbye. Jones said the CMU team will never see that model again, because the extreme exposure to radioactivity will require the Department of Energy to dispose of it. 

But RapPiper will live on, as the institute continues to adapt the robot for more uses. Each version is a little martyr for health and safety.