Inspection drones are one the fastest growing components of the global UAV industry.  In fact, the types of inspection drones vary widely, almost as widely as the kinds of niches in which they’re needed.  One basic difference is between indoor and outdoor inspection drones.  While outdoor drones typically survey power grids and oil and gas pipelines, indoor drones are best suited for  warehouses, collapsed buildings and mines, or for specific public safety scenarios – the scene of a fire or hostage taking, for example.

Still, there’s one especially delicate and dangerous indoor scenario that only a few drone suppliers can handle with minimal risk:  Nuclear reactors and waste sites.

In Japan last week, officials at the Tokyo Electric and Power Company (TEPCO) began flying drones small enough to fit inside the palm of a hand into a nuclear reactor’s primary containment vessel to gather data on the level of radiation being released.  The sensor-equipped drones can collect data too dangerous for human field teams to gather and can also maneuver inside damaged reactors filled with debris and other obstacles.

In the past, TEPCO officials have tried to use ground-based robots to perform the same work but they too often fail to get the job done.  Drones can be remotely piloted to maneuver through narrow openings and around various obstacles while robots often get stuck or immobilized.

TEPCO’s highly-maneuverable drones weigh only 6.5 ounces and unlike ground-based robots, their whirring blades stir up minimal dust – which also makes them ideal for warehouse and manufacturing safety checks. Each drone is equipped with a front-loaded high-definition camera that captures live video and AI-powered sensors that collect data for subsequent processing.

TEPCO says it’s hoping data collected from the current drone flights will allow them to devise new means of removing reactor debris and even spent fuel – possibly by using more advanced and specially equipped drones with collection and storage capabilities.  TEPCO’s micro-drones conduct aerial surveillance, mapping and data collection and are restricted in their flight duration – just 5 minutes each, due their limited battery power  The company sends in one drone after the other to try to maintain a continuous surveillance operation.

This is not the first time TEPCO has turned to aerial vehicles for nuclear reactor inspections.  In fact, back in 2011, following the earthquake that crippled its reactors, the company turned to a then-cutting edge drone-like aircraft produced by Honeywell Corporation, that conducted close-in aerial surveys of the reactors to measure the extent of the damage.  It’s taken well over a decade for TEPCO to return to aerial vehicles, largely due to the failure of ground robots as well as underwater drones to provide the needed surveillance and data collection capabilities.  In 2015, one ground robot became stuck in a reactor entrance gate and could not be retrieved.  The precise location and disposition of the immobilized robot wasn’t fully known until TEPCO made the decision to resume aerial drone flying.  The manufacturer of TEPCO’s current drone fleet remains unknown.

Japan appears to be the second major Western nation to deploy remotely piloted drones inside a nuclear reactor.  Last year, 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.  The eight enormous cylindrical vaults containing hazardous waste material are not designed for human entry, and the positioning and maneuvering of conventional camera equipment inside the contained spaces could also prove precarious, possibly damaging the interior of a vault, and causing radioactive material to leak.

DOE contracted engineers deployed an Elios 3 drone equipped with LiDAR technology and designed by the firm Flyability, which specializes in indoor drone flying, to conduct the sensitive aerial mapping.  The engineers first constructed a mock nuclear reactor and tested the ability of the remotely piloted drone to conduct the work safely and efficiently.  In the actual deployment, it took the engineers just 7 minutes to conduct the mapping work.

The global indoor drone market is expected to quadruple in size between 2023 and 2031 – from about $10 million to more than $40 million over this 8-year period.  Nuclear inspections, while still a relatively small component of the total market, will increase exponentially as more reactors are decommissioned and as environmental waste disposal compliance requirements continue to grow, experts say.