The robotic Light-Duty Utility Arm is proving itself useful throughout the DOE complex. Designed for the safe and cost-effective inspection of DOE’s storage tanks and for the characterization and retrieval of the high-level radioactive and hazardous waste stored therein, the LDUA allows for more representative sampling and inspection than was previously possible. Initiatives first reported on the LDUA in its April 1995 issue and has followed successful deployments of the LDUA at Oak Ridge National Laboratory in Tennessee and the Hanford Site near Richland, Washington. In February, the LDUA was used at the Idaho National Engineering and Environmental Laboratory near Idaho Falls. DOE’s Office of Science and Technology, through the Tanks Focus Area, provides funding that makes possible the development and manufacturing of these robots to meet user-specified needs.

The High-Level Waste Program at INEEL used its LDUA to inspect the inside of tank WM-188, an underground liquid radioactive waste storage tank, and to take samples from the residue, or heel, that was left when the tank was emptied. The data collected from tank WM-188 will be used to support future activities and achieve environmental compliance at the Idaho Nuclear Technology and Engineering Center and will help in the development of plans for closing the tank farm.

The LDUA brings together technologies developed at multiple U.S. Department of Energy laboratories. The system includes a flexible robotic arm, a telescoping deployment housing, a deployment vehicle, an operations trailer, and specialized tools called end effectors.

INEEL’s LDUA was built by Spar Aerospace, Ltd. of Toronto, Canada. It is adapted from a truck-mounted design first developed for the Hanford Site by Spar Aerospace. The utility arm is 13.5 feet long and has seven joints, which are controlled by operators using advanced computer models, computer commands, and a “joy stick.” The system can be extended 54 feet and is equipped with cameras so operators in the control trailer can see on a video screen what they are doing as they use the end effectors inside the tank.

During February’s INEEL deployment, three end effectors were used with the robotic arm of the LDUA: a video camera to view the interior and heel of the tank, a nondestructive examination tool to inspect the tank walls and welds, and a sample collector to retrieve heel samples.

The deployment of the LDUA at INEEL is the result of more than a decade of development work at INEEL. Most of the supporting subsystems used with the LDUA at INEEL were developed, designed, and built by INEEL robotics engineers. The sampling end effector was also developed by INEEL, and the other two end effectors were provided through collaboration with Oceaneering Space Systems and the Savannah River Technology Center.

Cleaning of the arm and end effectors after each entry and collecting and transferring heel samples to containers were done remotely inside a confinement system to prevent personnel exposure and releases to the environment.

The LDUA and its control system were assembled, programmed, and tested at INEEL’s Fuel Processing Restoration facility last year. Once the system was fully tested and readiness to deploy was approved, the system was moved on four trailers to the tank farm.

The High-Level Waste Program at INEEL plans to use its LDUA to help close 11 underground storage tanks and in other applications. Additional end effectors are being developed to perform expected closure activities.

Before the LDUA was developed, tanks and their contents were characterized by sampling from and viewing the area directly below the opening riser in a tank, which was not representative of the entire tank itself. The LDUA provides freedom to sample from and view a larger portion of the tank.