IDAHO FALLS, Idaho – The EM Idaho Site’s Calcine Retrieval Project team recently tested a robotic crawler to adhere to the interior surface of a waste storage vessel and remove residual granulated calcine, a high-level waste.
Calcine is a granular byproduct of a process called calcining used at the site from 1963 to 2000 to convert high-level radioactive liquid waste from spent nuclear fuel reprocessing to a stable solid. It is stored in large stainless steel bins inside six concrete vaults known as bin sets at the Idaho Nuclear Technology and Engineering Center. The team is tasked with transferring approximately 220 cubic meters of material from an old bin set to a new one and closing the old bin set under the Resource Conservation and Recovery Act.
Program engineers expect some residual calcine to remain in the vessels after primary retrieval and transfer. The team envisions the crawler to maneuver throughout the interior of the bins, removing residual calcine by using air jets to blow it down to the inlets of the primary retrieval system, or by using a vacuum system to remove calcine directly. The crawler uses a vacuum system with 400 pounds of pulling force to adhere to vertical walls, while independently-controlled wheels allow it to drive in any direction regardless of orientation.
“We tested a robotic snake arm earlier this year, which performed well, but our goal is to develop and test several technologies and choose the best one for the task,” said Howard Forsythe, project manager for EM cleanup contractor Fluor-Idaho.
In initial testing, the crawler prototype demonstrated its ability to maneuver freely on a vertical steel surface similar to the interior walls of the bins. Further testing and design development is planned over the next several months. This testing is expected to demonstrate the ability of the crawler to deploy, maneuver, and perform cleanout operations.
The team expects to begin calcine retrieval and transfer by fiscal year (FY) 2020 and close the old bin set by FY 2022. Ultimately, all 4,400 cubic meters of calcine must be retrieved and ready to ship out of Idaho for disposal in compliance with an agreement between DOE and the State of Idaho.