Drones to venture into Fukushima containment vessels

Unmanned aerial system technology is being developed to fly into the containment vessels of the damaged reactors at the Fukushima Daiichi nuclear power plant in Japan to assess their condition. Tokyo Electric Power Company contracted the Southwest Research Institute (SwRI) of the USA to carry out the work.

The greatest challenge in decommissioning the plant will be removing the fuel debris from the three reactors that suffered meltdowns in the March 2011 accident. However, radiation levels in those reactor buildings remain too high for workers to enter. Therefore remotely operated equipment, such as robots, is needed to carry out investigations and tasks within those areas.

A number of ground- and underwater-based robotic systems have already been sent inside the containment vessels of units 1, 2 and 3. However, damage and high radiation levels have limited access to information vital to decontamination and decommissioning efforts.

San Antonio, Texas-based SwRI, working with the General Robotics, Automation, Sensing and Perception (GRASP) laboratory at the University of Pennsylvania's School of Engineering and Applied Science, is helping adapt small drones to operate autonomously within the containment vessels of the damaged reactors.

The team has demonstrated the feasibility of their approach in a test fixture at SwRI's San Antonio campus late last year. During the project, the SwRI-UPenn team demonstrated that the drone was capable of autonomously navigating in a confined, GPS-denied environment, avoiding obstacles along the flight path, and surviving the radiation levels expected during a mission inside of the units at Fukushima Daiichi.

"This is a formidable challenge," said project manager Monica Garcia, a senior research engineer in SwRI's Intelligent Systems Division. "The conditions inside the containment at Fukushima Daiichi are quite possibly the most challenging environment that the SwRI-Penn team has had to address. We will be pushing the envelope in terms of the technology."

Technical lead Richard Garcia, also a senior research engineer at SwRI, said: "The team is adapting high-speed, advanced mobility drones to collect key information about the current status. This information will play an important role in future decontamination and decommission efforts at Fukushima Daiichi."

Vijay Kumar, the Nemirovsky Family Dean of Penn's School of Engineering and Applied Science, said: "As robots get smaller, faster and smarter, this is exactly the kind of problems we want them to address. Challenges like this are what push research in our field forward."

Last month it was announced a small drone is to be deployed to map radiation levels within the reactor buildings of the damaged Fukushima Daiichi units. The UK-developed RISER - Remote Intelligence Survey Equipment for Radiation - has already been used at Sellafield, in England.

Researched and written
by World Nuclear News