One of the nice things about robots is that they can do stuff we humans can't or don't want to do. Last year, when the Great Tohoku earthquake damaged the Fukushima Daiichi nuclear plant and caused the second worst nuclear meltdown in history, robots came in handy. Radiation levels were unsafe for humans, so we sent in the bots.
Photo by zcopley
Over the last year, a number of different robots have been used for monitoring, collecting data and cleaning up. The situation is far from stable and they're still being used today. PackBots, which look a little like Johnny 5 from the movie Short Circuit, were sent in to measure radiation levels and take pictures. Warriors were sent in to clean and decontaminate. Monirobos (short for monitoring robot) went in to get samples and monitor temperature and humidity levels.
The Quince rescue robot
Lately, they're using the Quince rescue robot. Developed by Eiji Koyanagi of Chiba Institute of Technology, Quince 1 was first sent into the plant in June 2011 as a surveyor. One of the advantages of this robot is that it can be controlled remotely from up to a mile and a half away.
Quince has a flat chassis and rotating caterpillar tracks that let it climb stairs. On top of its chassis is mounted a variety of gadgets for monitoring that includes a camera. It also has an arm that can be used to remove debris or obstacles and the body is waterproof.
The demise of Quince 1
Robots can be adversely affected by radiation just like humans and researchers weren't sure how it would fare the first time it was sent in. Quince can only function for a few hours while exposed to the high radiation levels inside the plant. This makes it tough for them to get the samples and take the readings they need.
Initially, Quince made it in and out with no trouble. Unfortunately, while roaming around somewhere on the third floor of the reactor in October 2011, it disappeared. All contact was lost. It turns out that the robot worked exactly as it was designed to but it was stopped by a faulty cord.
This led to the development of Quince 2 and 3, which were sent into the reactor in February 2012. They're both improved versions of Quince 1. Quince 2 is equipped with a dust sampler and Quince 3 has a 3D scanner. One of the biggest improvements is that they operate on the buddy system. If one of them disappears, the other will automatically go to its aid and supply the power it needs to get moving again.
The Fukushima robot today
In late March 2012, one of the Quince robots was sent in to check on an unusual thermal reading in a certain area of the reactor. While inside, they checked the radiation levels as well.
According to an article in the Japan Times, radiation levels were much higher inside the plant than previously assumed. With the help of Quince, it's much easier for Tepco officials to understand what's going on in the stricken plant.