Boston Dynamics' Spot Is Helping Chernobyl Move Towards Safe Decommissioning
In terms of places where you absolutely want a robot to go instead of you, what remains of the utterly destroyed Chernobyl Reactor 4 should be very near the top of your list. The reactor, which suffered a catastrophic meltdown in 1986, has been covered up in almost every way possible in an effort to keep its nuclear core contained. But eventually, that nuclear material is going to have to be dealt with somehow, and in order to do that, it's important to understand which bits of it are just really bad, and which bits are the actual worst. And this is where Spot is stepping in to help.
The big open space that Spot is walking through is right next to what's left of Reactor 4. Within six months of the disaster, Reactor 4 was covered in a sarcophagus made of concrete and steel to try and keep all the nasty nuclear fuel from leaking out more than it already had, and it still contains 30 tons of highly contaminated dust, 16 tons of uranium and plutonium, and 200 tons of radioactive lava." Oof. Over the next 10 years, the sarcophagus slowly deteriorated, and despite the addition of that gigantic network of steel support beams that you can see in the video, in the late 1990s it was decided to erect an enormous building over the entire mess to try and stabilize it for as long as possible.
Reactor 4 is now snugly inside the massive New Safe Confinement (NSC) structure, and the idea is that eventually, the structure will allow for the safe disassembly of what's left of the reactor, although nobody is quite sure how to do that. This is all just to say that the area inside of the containment structure offers a lot of good opportunities for robots to take over from humans.
This particular Spot is owned by the U.K. Atomic Energy Authority, and was packed off to Russia with the assistance of the Robotics and Artificial Intelligence in Nuclear (RAIN) initiative and the National Centre for Nuclear Robotics. Dr. Dave Megson-Smith, who is a researcher at the University of Bristol, in the U.K., and part of the Hot Robotics Facility at the National Nuclear User Facility, was one of the scientists lucky enough to accompany Spot on its adventure. Megson-Smith specializes in sensor development, and he equipped Spot with a collimated radiation sensor in addition to its mapping payload. We actually built a map of the radiation coming out of the front wall of Chernobyl power plant as we were in there with it," Megson-Smith told us, and was able to share this picture, which shows a map of gamma photon count rate:
Image: University of Bristol Researchers equipped Spot with a collimated radiation sensor and use one of the data readings (gamma photon count rate) to create a map of the radiation coming out of the front wall of the Chernobyl power plant. So what's the reason you'd want to use a very expensive legged robot to wander around what looks like a very flat and robot friendly floor? As it turns out, the floor is very dusty in there, and a priority inside the NSC is to keep dust down as much as possible, since the dust is radioactive and gets on everything and is consequently the easiest way for radioactivity to escape the NSC. You want to minimize picking up material, so we consider the total contact surface area," says Megson-Smith. If you use a legged system rather than a wheeled or tracked system, you have a much smaller footprint and you disturb the environment a lot less." While it's nice that Spot is nimble and can climb stairs and stuff, tracked vehicles can do that as well, so in this case, the primary driving factor of choosing a robot to work inside Chernobyl is minimizing those contact points.
Right now, routine weekly measurements in contaminated spaces at Chernobyl are done by humans, which puts those humans at risk. Spot, or a robot like it, could potentially take over from those humans, as a sort of automated safety checker"Right now, routine weekly measurements in contaminated spaces at Chernobyl are done by humans, which puts those humans at risk. Spot, or a robot like it, could potentially take over from those humans, as a sort of automated safety checker" able to work in medium level contaminated environments." As far as more dangerous areas go, there's a lot of uncertainty about what Spot is actually capable of, according to Megson-Smith. What you think the problems are, and what the industry thinks the problems are, are subtly different things.
We were thinking that we'd have to make robots incredibly radiation proof to go into these contaminated environments, but they said, can you just give us a system that we can send into places where humans already can go, but where we just don't want to send humans." Making robots incredibly radiation proof is challenging, and without extensive testing and ruggedizing, failures can be frequent, as many robots discovered at Fukushima. Indeed, Megson-Smith that in Fukushima there's a particular section that's known as a robot graveyard" where robots just go to die, and they've had to up their standards again and again to keep the robots from failing. So the thing they're worried about with Spot is, what is its tolerance? What components will fail, and what can we do to harden it?" he says. We're approaching Boston Dynamics at the moment to see if they'll work with us to address some of those questions.
There's been a small amount of testing of how robots fair under harsh radiation, Megson-Smith told us, including (relatively recently) a KUKA LBR800 arm, which stopped operating after a large radiation dose of 164.55(1.09) Gy to its end effector, and the component causing the failure was an optical encoder." And in case you're wondering how much radiation that is, a 1 to 2 Gy dose to the entire body gets you acute radiation sickness and possibly death, while 8 Gy is usually just straight-up death. The goal here is not to kill robots (I mean, it sort of is), but as Megson-Smith says, if we can work out what the weak points are in a robotic system, can we address those, can we redesign those, or at least understand when they might start to fail?" Now all he has to do is convince Boston Dynamics to send them a Spot that they can zap until it keels over.
The goal for Spot in the short term is fully autonomous radiation mapping, which seems very possible. It'll also get tested with a wider range of sensor packages, and (happily for the robot) this will all take place safely back at home in the U.K. As far as Chernobyl is concerned, robots will likely have a substantial role to play in the near future. Ultimately, Chernobyl has to be taken apart and decommissioned. That's the long-term plan for the facility. To do that, you first need to understand everything, which is where we come in with our sensor systems and robotic platforms," Megson-Smith tells us. Since there are entire swathes of the Chernobyl nuclear plant where people can't go in, we'd need robots like Spot to do those environmental characterizations."