Cleaning up former weapons and nuclear energy test sites is a job fraught with peril.  The threat of spreading radioactive contamination to nearby communities is one obvious risk; another is the very real possibility of poisoning the workers charged with the waste removal.  Safety protocols are strict and the need to secure approval from various federal and local authorities can delay the clean-up process interminably.

US Department of Energy officials in Idaho decided to expedite the process by deploying remotely piloted drones to identify the waste materials at a decades-old nuclear test site and to test the radiation levels in the storage airspace to prepare workers for the dangerous task of waste removal.

Officials say it was the world’s first piloted drone mission inside a high-level radioactive waste storage vault and the mission – completed in just minutes compared to the many hours of hands-on field inspection typically required – was a smashing success.

Officially, the drone mission was known as the Calcine Removal Project (CRP), so named for the hazardous waste material that was first stored in a set of eight enormous cylindrical vaults over a half century ago.  The bins are not designed for human entry and positioning and maneuvering conventional camera equipment inside the contained spaces could also prove precarious, possibly damaging the interior of a vault, and causing radioactive material to leak.

“Mapping the inside of this vault is a challenging problem,” says Kevin Young, one of three CRP engineers that received special drone flight training to conduct the mission.  “The vault is not designed for human access, and even if it were, the radiation levels are way too high for a person to go inside. Using the drone is the safest and most cost-effective solution for getting the data we need.”

The first part of the mission was simply to create an accurate 3-D map of the storage bins that will allow federal officials to design proper vehicles to conduct the actual waste retrieval.  The calcine – originally a liquid that was transformed into a solid that resembles dry laundry detergent – was stored so long ago that officials can barely remember the kinds of storage bins that were used, and how best to access them.

On the advice of Idaho Environmental Coalition (IEC), which is supporting the project under a ten-year $6.4 billion DOE contract, CRP engineers deployed an Elios 3 drone equipped with LiDAR technology and designed by the firm Flyability, which specializes in indoor drone flying.  To ensure the project’s success, the IEC built a life-sized replica of the vault so that the three CRP pilots could be trained in an environment that simulated the real world in which they planned to fly.  In fact, the entire drone mapping mission proved to be brief – and uneventful.  The three CRP fliers were able to collect all the LiDAR data needed to create a robust 3D map of the vault in just one seven-minute flight.

With the mapping complete, the next big step is removing the calcine.  Once removed, the waste must then be treated and repackaged, a laborious process that could take years.  Under a settlement agreement reached in 1995, all waste materials stored at the site must be removed by 2035, which means time is of the essence.  Having mapping and radiation testing drones available at various stages of the process will allow the feds and the state to meet their settlement deadline, officials say.

In a media release, Flyability touted the success of the Idaho mapping project and promised to make additional contributions as the project evolves through its successive stages.

“After over a year of preparation it has been incredibly exciting to see this project conclude successfully,” said Alexandre Meldem, Managing Director of Flyability North America. “We are always looking for ways Flyability’s technology can be leveraged to gather data that would be hard or even impossible to collect otherwise.

Currently, Flyability drones are being used to conduct indoor aerial inspections at 80% of US nuclear facilities, greatly reducing the cost of human inspectors.  In 2021, the firm introduced the Elios 3 drone to allow for pinpoint measurements of nuclear radiation dose levels as part of its ongoing inspections.  The Idaho project – where the Elios 3 received its first real-world application –  is expected to lead to missions at several other nuclear waste sites facing deadlines for closure.