Argonne’s ‘BattleBot’ can clean those hard-to-reach spots
In the inhospitable environment of the Alpha-Gamma Hot Cell Facility (AGHCF), located at the U.S. Department of Energy’s Argonne National Laboratory, a new robotic addition helps to clean house.
The “BattleBot,” which uses a frame built for the eponymous TV show, is a small remotely controlled vehicle that can fit under tables and into tight corners to collect material that couldn’t otherwise be reached.
In 1964, the Hot Cell Facility was created as a self-contained environment where researchers could manipulate and test radioactive nuclear fuel rods. The cell consists of three areas filled with nitrogen gas and enclosed by three-foot-thick concrete walls. Dense zinc bromide solution serves as shielding within the window tanks.
After more than 50 years of fuel testing, Argonne decided to limit its “nuclear footprint” by decommissioning most of its nuclear facilities, including the hot cell.
For the past eight years, technicians have remotely categorized, sectioned and packaged fuel samples and irradiated materials with manipulators and robotic arms. These manipulators, set up at each of the cell’s nine workstations, are completely mechanical and can be used to work with highly radioactive materials inside the cell.
But technicians found it difficult to recover material that, over the years, had been dropped under work stations and in unreachable corners of the cell.
Kyle Haske (NWM), chief technician at the facility, has been working on the project for six years.
“What we needed was a small robot that could do multiple functions and operate at a level below the workstations,” Haske said. “We really had no way of getting at some of the fuel and debris that’s been kicked under the tables.”
The BattleBot was developed and built by Electronics Specialist James Bulka (HEP), based on requirements from hot cell technicians. Bulka started work on the robot in 2010, using radio flyer technology to build new controllers and working with an unadorned BattleBot chassis.
“The company that I bought it from builds a lot of surveillance and tactical robots,” Bulka said. “But the electronics provided by the manufacturer would not have lasted very long with such high radiation, so I used the basic chassis and built the rest myself.”
After the first pass at the design, the hot cell team worked with Bulka to incorporate further improvements to the motors, gearing, batteries and electrical components to meet the requirements for cell deactivation.
“We started with a simple chassis, beefed up the frame, tripled the size of the motors, mounted an actuated plow, put on heavier-duty tracks, wired it for remote operations and installed oversized deep cycle batteries.” Haske said. “This is a very robust robot.”
The benefits of a small robot in an environment like the hot cell are numerous: This nuclear-grade BattleBot can use customized attachments to sweep and vacuum up debris, perform cable management for the larger robots and transport waste containers up to 150 pounds in weight.
The BattleBot can also be equipped with a camera to view its surroundings and a radiation detector, to map out hotspots around the cell. Some material in the cell can reach up to 500 R per hour; in other words, standing for one hour in the radiation field is equivalent to about 800 times the yearly natural background radiation levels for an average person.
Today the facility focuses on two main operations: Reducing the volume of irradiated materials in the cell and a program called Drum Repatriation. The Repatriation consists of technicians reinserting materials into the cell that were improperly packaged or have insufficient documentation and repackaging them into their RH-TRU waste stream. It’s also the only facility capable of transferring rare isotope source materials for the CARIBU upgrade at the Physics Division’s ATLAS accelerator between shipping containers.
After the de-inventorying has been completed, the BattleBot will finish up with a sweep and a vacuum of the dust and waste filings left on the floor before being taken apart and removed.
“It’s definitely a piece of equipment that I think other facilities like this one can utilize for gross deconstruction and equipment recovery,” Haske said.
The BattleBot radiation detector was provided as part of the Watchful Guardian system, which was installed by the Yung Liu group in the Nuclear Engineering Division.
Kate Thackrey (CEP)