One Job the Robots Can Have: Cleaning Nuclear Waste
A new model of cleanup bot “will make its own decisions.”
To enter Europe’s largest nuclear site, a visitor must be wearing construction coveralls, steel-toed boots, a hard hat, and a pager-size device that rings if radiation levels get too high. Contamination enters the body through open wounds, so any cuts must be bandaged with medical tape. On the way out, after you remove your protective gear, a security guard sweeps your body with a handheld detection device to make sure nothing latched on. It’s as unsettling as it sounds.
This is Sellafield, on the coast of the Irish Sea, more than 300 miles north (and a bit west) of London. At the dawn of the Cold War, the U.K. chose this site as the place to begin enriching uranium for its first nuclear weapon. But in the country’s haste to build a bomb, little thought was given to disposing of the waste. Much of it was placed in concrete ponds larger than Olympic swimming pools. In 1957 a reactor fire contaminated the local countryside and a devastating meltdown was narrowly avoided.
Generations later, scientists, engineers, and government officials are still grappling with the leftover waste. The concrete ponds, surrounded by dilapidated and moldy scaffolding, are filled with murky green water that keeps the waste cool. Hundreds of tons of radioactive material are in the structures, risking leaks into the soil or a fire. The area has been classified an “intolerable risk” for falling short of modern safety standards, a problem that must be addressed over the next two decades. “There is a time imperative,” says Rebecca Weston, Sellafield’s technical director.
That urgency is leading Weston and her colleagues to seek help from robots, an important step for the delicate business of nuclear waste. Advances in software and hardware engineering are allowing machines to reach contaminated areas that humans could never survive. The U.K. government is spending about £2 billion ($2.5 billion) a year at Sellafield, helping make the otherwise sleepy countryside region of West Cumbria an unexpected proving ground for nuclear decommissioning technology. “I’ve traveled in Korea and Japan, to Fukushima, and West Cumbria is looked at as a technology hub,” says Mark Telford, managing director for Forth Engineering, a robotics company working with Sellafield.
Forth is developing a £500,000 six-legged machine about the size of a coffee table. The robot is packed with cameras and sensors to see its environment. A giant pincher on the front grabs contaminated material and breaks it up. Magnets on the machine’s feet will enable it to crawl up walls. Artificial intelligence software allows a team of the robots to work without humans at the controls, communicating with one another to complete a task. If one breaks down, others take over. “The robot will make its own decisions on how it walks, what it sees, and its interpretation of its environment,” Telford says.
Forth has a working prototype, but says the finished product is 18 months away, will need to stay plugged in to a power source, and requires a human operator’s OK for delicate tasks like moving a fuel rod. It’s also unclear how it’ll respond to long-term radiation exposure. Even for robots, Forth says, there’s no coming back from some of the most dangerous areas.
Inside Sellafield’s decaying waste ponds, robots from other manufacturers scoop up sludge and other debris and drop it into steel containers later placed in silos. “That little machine has removed thousands of items,” says drone operator Keith Ashbridge.
The robots are giving officials a look inside contaminated areas that have long been abandoned. Createc, another startup working with Sellafield, has developed a quadcopter drone nimble enough to fly in the office kitchen, or through holes made by the 1957 reactor fire. It’s loaded with cameras, air-pressure sensors, gyrometers, accelerometers, and other measuring tools that stream back 3D maps locating the radioactive material. Officials in Japan have hired Createc to build maps for the Fukushima cleanup.
Those who’ve worked on decommissioning Sellafield say technology isn’t a magic bullet. The 70-year-old site—home to 10,000 employees and its own rail service and police and fire departments—looks its age and will eventually cost at least £90 billion to properly clean up, says Paul Dorfman, honorary senior researcher at the Energy Institute at University College London. And even as robots work to scrub Sellafield’s most dangerous areas, more waste continues to arrive from elsewhere in the U.K., Europe, and Japan. All told, Sellafield houses one of the largest stockpiles of plutonium in the world and receives about £800 million a year to reprocess and manage spent nuclear fuel.
Dorfman says Sellafield’s problems reflect how the expense and danger of dealing with nuclear waste are often hugely underestimated. The government’s estimated cost to clean up Sellafield has almost doubled over the past decade. With renewable power becoming cheaper, Dorfman says the carbon-free benefit of nuclear power isn’t worth the risk. “You have to understand the depth of the problem,” he says. Nuclear waste remains radioactive for thousands of years, and the government still doesn’t have a long-term place to store it, even if robots can clean it up effectively. The U.S., France, Germany, and Japan face similar storage challenges.
Even if every nuclear power plant in the world were shut down tomorrow, it would take a century or more to deal with the waste, and that task will increasingly fall to machines. With powerful computers being squeezed onto smaller chassis, robots in the next decade will acquire better decision-making skills, giving them the ability to improvise within unpredictable environments, says Paul Mort, who leads Sellafield’s robotics and autonomous systems development. “It’s not that far away,” he says. In an era when people are concerned about job-snatching robots, Mort says, this is one task humans will gladly cede to machines.
The bottom line: Europe’s biggest nuclear waste dump is a proving ground for increasingly self-sufficient drones, which are working to clean it up.