Mission Results - Creating a 3D-Map of a High-Radiation Confined Space Using the LiDAR Equipped Elios 3 Drone - 23074

This paper describes preparations, execution, and results associated with using the LiDAR-equipped Elios 3 inspection drone, from Flyability, to create a 3D-map of obstructions and collect radiation readings within the very high radiation area, confined space of the Calcined Solids Storage Facility 1 (CSSF 1) storage vault located at the Department of Energy's (DOE) Idaho National Laboratory (INL) Site. Idaho Cleanup Project (ICP) engineers will use the 3D-map to remotely position equipment necessary for the extraction of 220 cubic meters of highly radioactive powder known as calcine from storage bins housed within the vault. Preparations for flying the Elios 3 drone inside the CSSF 1 storage vault included conducting a maneuverability test, a radiation tolerance test, a dosimeter payload test, an elevated ambient temperature test, and mission simulation training for the pilots. The radiation tolerance test was conducted in collaboration with the Idaho Accelerator Center and Flyability. ICP engineers tested the newly released Elios 3 drone on June 1 and 2, 2022 at the Idaho Accelerator Center on the campus of Idaho State University. To complete the LiDAR data collection mission within the CSSF-1 vault, engineers estimate the drone must remain functional in a minimum radiation field of 10 Gy/h (1,000 rad/h) and continue to function after an accumulated dose of 10 Gy (1,000 rad). Radiation test results indicated the drone successfully operated in a 100 Gy/h (10,000 rad/h) field and continued to function after an accumulated dose of approximately 40 Gy (4,000 rad), greatly exceeding the minimum requirements. Thermal testing of the Elios 3 drone motors occurred on October 6, 2022. Results of the elevated ambient temperature test indicate the motor temperatures levelled out just below 90 deg. C (194 deg. F) after approximately 2.5 minutes of flight at an ambient temperature of 54 deg. C (130 deg. F). This is below the drone's initial warning temperature threshold of 95 deg. C (203 deg. F). Another critical preparatory task for flying the drone within the CSSF 1 storage vault included training ICP personnel to pilot and operate the drone. Formal training was provided by Flyability on July of 2022 to three ICP drone pilots. This was followed by more than 20 hours of combined flight-training by these pilots that included flying the drone through a mission-simulator mockup. The Elios 3 drone mission within the CSSF 1 storage vault occurred on November 16, 2022. ICP Pilots successfully flew the Elios 3 inspection drone within the very high radiation, confined space of the vault. Two flights, each lasting about six minutes and 30 seconds, were completed to collect the LiDAR data resulting in a complete 3D-map of all obstructions above the calcine storage bins. The flight-stability software along with the lightweight, carbon-fiber cage were key features of the Elios 3 drone contributing to the success of this mission. A second mission was conducted on the same day, immediately after the LiDAR data was successfully collected. The purpose of this mission was to obtain radiation readings within the vault. In collaboration with Flyability, an ICP provided electronic dosimeter, with RF transmission capability, was attached to the drone for a third flight into the vault. For reasons not fully understood, after the drone entered the vault, it was not able to produce enough lift to maintain altitude. It made a slow descent to the top of one of the storage bins and became snagged on a piece of angle iron. All attempts to free the drone failed. Before the battery died, the drone was able to transmit a maximum radiation reading of 7 Gy/h (700 rad/h) at the top of the bin. A GeoSlam software expert used GeoSlam Connect Draw software to perform an initial review of the LiDAR data to assess the accuracy of the collected LiDAR data. The preliminary evaluation indicated the accuracy of the 3D-map created from the LiDAR data is well under 1 cm (0.39 in) and exceeds the minimum accuracy required by the Calcine Retrieval Project of 2.54 cm (1.0 in). In addition to the LiDAR data, the Elios 3 drone collected 4K resolution video of conditions within the CSSF 1 storage vault which will provide a valuable reference throughout future calcine retrieval operations. The successful completion of this mission provides an example of how the Elios 3 LiDAR-equipped drone was used to collect critical, LiDAR data, imagery, and radiation readings from inside a very high radiation confined space. The authors hope the information in this paper will help others involved in waste remediation projects with similar data collection challenges. (authors)