Robots Job : Cleaning Nuclear Waste

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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.

 

For decades, the Sellafield plant in Cumbria could lay claim to being one of the most controversial industrial complexes in Britain.

Now, however, it is playing a new role – as a giant test bed for specialised technology and techniques used in nuclear decommissioning.

Flying drones, remote controlled submarines and industrial robots have all been brought in to carry out tasks which are simply too dangerous, or even impossible, for humans to do.

Chequered history

The first reactors at Sellafield, at that time known as Windscale, were rushed into service in the early 1950s.

Their role was to produce plutonium for the country’s atomic weapons programme.

But cold war power came at a price. Infamously, one of the reactors caught fire in 1957, contaminating the surrounding farmland.

A major disaster was only narrowly avoided.

Despite that setback, the site at Sellafield continued to grow.

The world’s first commercial nuclear power station – Calder Hall – was built there, for example.

It also became a hub for the nuclear reprocessing industry.

Sellafield
Image captionThe clean-up of Sellafield’s nuclear waste is only just getting under way, says Theo Leggett
Aerial view of Sellafield in 1956Image copyrightGETTY IMAGES
Image captionBritain’s first nuclear power station, Calder Hall, was opened in 1956

Now, though, the plant is winding down.

Apart from waste storage, all of its major activities are due to cease over the next few years.

Cleaning up the mess left behind is a major challenge.

“I’d love to be able to say to you that we’ve got very good records of all the material that we have in these facilities,” says Kevin Gunston of Sellafield Ltd, the company responsible for the decommissioning process.

“But that just isn’t the case. So one of the challenges we have is to understand exactly what material we have and where it is, so we know what we can do with it in the future”.

Robot submarines

That’s where the submarines come in.

Much of the waste that accumulated at Sellafield over the decades was stored underwater, in giant open air tanks, known as ponds.

It included used fuel waiting to be reprocessed, contaminated materials and other discarded machinery.

Robot in water tank
Image captionThe tethered robots can swim and film underwater

But corrosion and spillages meant the water became murky, and the bottom of the ponds became covered with a thick layer of highly radioactive sludge and debris.

To find out what is down there and start to get rid of it, Sellafield Ltd has been using a fleet of mini-submarines, or Remotely Operated Underwater Vehicles (ROVs).

The smallest models can almost be held in the palm of your hand. They are camera drones, designed for advanced reconnaissance.

“These are used for going into very congested areas, very high hazard areas,” says Philip Toomey, ROV innovation manager at Sellafield.

Robotic cheetahImage copyrightGETTY IMAGES
Image captionThe 2011 Fukushima nuclear meltdown in Japan accelerated development of disaster response robots

“Some of these areas, we haven’t been into for over 40 years”.

Larger ROVs, about the size of a washing machine, are used for tasks such as removing old fuel rods from underwater skips, or sucking up sludge from the pond floor.

All of these machines have to be able to cope with very harsh conditions.

“The water itself is very acidic, and of course there’s lots of radiation and contamination,” says Mr Toomey.

Resilient design

One of the companies developing the subs on behalf of Sellafield is James Fisher Nuclear. Much of the technology it uses is adapted from systems already employed in the offshore oil and gas industries.

“It’s more cost-effective if we can use off-the-shelf designs where possible,” says Simon Pyne, the company’s business development manager.

Simon Pyne, James Fisher Nuclear
Image captionSimon Pyne, of James Fisher Nuclear, stands in front of one of his firm’s submarine robots

“It’s also much quicker than developing something from scratch.”

He adds that it’s surprising just how resilient bought-in designs can be to the high levels of radiation in the water.

Chimney challenge

But clean-up challenges at Sellafield are not confined to the storage ponds. Some of the other buildings on the site also represent unique challenges.

The skyline above the plant, for example, is dominated by a single tall chimney. It is one of two constructed to ventilate the original Sellafield reactors – the infamous Windscale Piles.

Its twin was demolished more than a decade ago, but this one remains standing.

It was heavily contaminated during the 1957 fire, when a plume of radioactive smoke poured up it from the burning reactor core.

Man holding quadcopter droneImage copyrightSELLAFIELD LTD
Image captionDrones can inspect areas of high radiation that would be dangerous for humans

Now, demolition works have begun, but the contractors have to be careful, because parts of the building are still radioactive.

So to find out more, they’re using a drone.

The Riser (Remote Intelligence Survey Equipment for Radiation) is a quadcopter equipped with systems that allow it to navigate inside a building, without GPS.

It also has radiation sensors, which enable it to build up a 3D map of the inside of the chimney, with contamination picked out in bright colours.

The drone, a collaboration between Cumbrian firm Createc and Bedfordshire-based Blue Bear Systems Research, has already been tried out successfully inside the chimney and will be used in other parts of the plant as well.

The radiation-mapping technology, meanwhile, has already been employed overseas – inside the heavily-contaminated Fukushima Daiichi plant in Japan.

Tried and tested

Not all the robots being put through their paces in and around Sellafield are so obviously cutting-edge, however.

On a test rig at the nearby National Nuclear Laboratory facility, three giant orange robot arms are being put through their paces. They are tearing apart rusty drums, bits of masonry and bars of unidentified metal, before packing the remains into shiny new containers.

If the robots work as intended, they’ll eventually be taken to Sellafield where they’ll process nuclear waste recovered from ponds and silos across the plant, preparing it for long-term storage.

Made by German specialist Kuka, they were originally developed for use in the car industry, and have been modified for their new task.

Robotic arms
Image captionGiant robotic arms could be used to tear up and pack up contaminated equipment in future

Well-proven technology is absolutely vital as servicing and repair becomes very difficult once these machines have been handling contaminated material.

For the moment, all of these technologies are being developed and refined primarily to help in the clean-up at Sellafield – a process that is expected to take up to 100 years to complete.

But nuclear decommissioning is a headache shared by many western nations, so the expertise being gathered here could find lucrative new markets abroad as well.

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.

Forth Engineering’s prototype is designed to gather data on and monitor its irradiated environment.
Photograph: Matthew Lloyd/Bloomberg

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.

The Sellafield nuclear waste site in northern England is an unusual proving ground for hardy robots.
Photograph: Matthew Lloyd/Bloomberg

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.

Contaminated water at Sellafield.
Photograph: Matthew Lloyd/Bloomberg

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.

A submersible VideoRay robot steers through one of Sellafield’s contaminated waste pools.
Photograph: Matthew Lloyd/Bloomberg

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.

 

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