AIKEN, S.C. – They crawl. They clean. They make work safer.
Highly hazardous working environments at the Savannah River Site (SRS) make it necessary to have robots complete important but remote work in areas where humans cannot go.
This National Robotics Week, April 7-15, Savannah River Remediation (SRR), EM’s liquid waste contractor at SRS, has several robots deserving of recognition. They do everything from radioactive waste tank sampling, inspecting, and cleaning to contaminated cell cleanup and remote repairs. And thanks to the SRR robots, the risk of the liquid waste is being reduced to the workers, the community, and the environment.
Waste tank closure is key to the SRS liquid waste mission. There are 43 underground waste tanks — each containing Cold War era radioactive liquid waste — left to be operationally closed. Robots are used in various steps of the closure process.
A crawler nicknamed G.I. Joe is used to sample the waste in the tanks. To retrieve the samples, G.I Joe is remotely controlled with the help of cameras to maneuver inside the tank. The robot’s arm grips a specially fabricated collection device used to scoop up the sample. Then the robot maneuvers to another area within the tank, where the sample is placed in a retrieval basket so it can be lifted from the tank.
SRR manages the surveillance of the aging tanks and uses robots to maintain the tanks’ integrity while they await closure. The primary tank walls and the outer annuluses are inspected with a remotely manipulated camera using high-resolution photography and ultrasonic inspections. The cameras and sensors for these inspections are deployed on wall crawler robots to help them maneuver around the tank.
Melt Cell Crawler
The Defense Waste Processing Facility (DWPF), operated by SRR, uses a vessel called a melter to glassify the high-level liquid waste into a glass form safe for long-term storage. Last year, workers replaced the melter. SRR called on EM’s Savannah River National Laboratory (SRNL) to help clean and remove radioactive debris that remained on the melt cell floor. SRNL modified a compact robot that was remotely deployed into the cell by crane. The laboratory also developed the tools needed for the robot to gather and package the debris for disposal.
Also in the liquid waste system are the evaporators, vessels that boil salt waste water until it evaporates, which in turn reduces the waste volume. In February 2016, one evaporator developed a leak into a contained, remote area. A dynamic robotic duo came to the rescue for repair. An arm called KUKA and a base called Brokk were joined together for repair preparations, which included removal of insulation around the vessel, holding a camera inside the cell, and maneuvering an ultrasonic probe to measure the thickness of the vessel. To complete the job, the pair welded a specialized cap onto the vessel to repair the leak site.