July 06, 2011      

Two months after the magnitude-9.0 earthquake and tsunami devastated northern Japan, leaving some 26,000 people dead and causing apocalyptic damage, workers finally entered the reactor buildings at the Fukushima Daiichi nuclear plant. Crippled by the killer waves and subsequent hydrogen explosions, radiation fallout worries from the plant had eased somewhat. Nevertheless, a large area of Fukushima Prefecture surrounding the plant remained uninhabitable. Fears surrounding the contamination of local produce and seafood, as well as the stain on Japan’s public image, would likely linger for years.

For all these reasons, Japanese officials ranked the accident alongside the Chernobyl disaster of 1986. Yet despite the fact that robots had played a role in alleviating the Chernobyl disaster and the earlier event at Three Mile Island, Japanese-made robots failed to make an appearance at the Fukushima site until weeks after the disaster began.

Made for the Job
Many observers saw a huge irony in the fact that robots were so slow to be deployed in response to the Fukushima disaster. Japan, the nation that produced Honda’s Asimo, has long prided itself on its robotics technology. Moreover, the Asian economic giant possesses roughly twice the number of industrial robots as all of North America, according to the latest annual World Robotics survey.

Indeed, when it comes to responding to nuclear crises, robots are an ideal tool. While unable to do everything humans can do, as first responders robots can provide a detailed picture of a damaged radioactive facility, recording radiation levels and cataloging damages, then relaying this vital information to users located a safe distance away. Robots have been deemed so important as nuclear disaster first responders, that France (see related article, “France’s Nuke-Bot Arsenal,” below), which like Japan has made an aggressive commitment to nuclear power generation, assembled a veritable army of robots specifically to serve as a failsafe measure. With 55 nuclear reactors in the archipelago, which provide nearly a third of total electricity, and its vaunted national expertise in robotics, it seems unthinkable that Japan had no robots to respond to a nuclear emergency.

As it turns out, Japan did develop such machines. After the 1979 Three Mile Island accident, Japan spent some $244 million on an inspection robot that could respond to nuclear emergencies, but the project was shelved in 1990. Then, after two workers were killed in an accident at a Japanese uranium-reprocessing facility in 1999, the precursor to the Japan Atomic Energy Agency created several prototype robots using billions of yen in public funds. One was RaBOT, a rolling, radiation-proof scout that could gather data in a nuclear accident. It had two arms and could open and close valves while operating under remote control. But in an astonishing public policy mistake, the government decided that these machines would never be viable in the real world, so it discontinued funding. One prototype even ended up at a children’s summer camp. As staff at Tokyo Electric Power Co. (TEPCO) and its many subcontractors exposed themselves to radiation to bring Daiichi under control, the government’s shortsightedness took on an especially tragic light.

First on the Scene
Yet another reason robots were absent from the Fukushima disaster scene was that the facility’s operator, TEPCO, didn’t have any. A month after the disaster, the first machines put into service were very basic: three remote-controlled, camera-equipped excavators donated by Japanese construction companies Shimizu and Kajima. Their deployment resulted from the fact that hydrogen blasts from the heat buildup within the reactors had scattered highly radioactive debris around the Daiichi compound. It soon became clear that the strewn wreckage was preventing both humans and robots from getting closer to the reactors, and so the excavators worked with dump trucks to clear as much as possible.

The next robots utilized at the site came from the United States. TEPCO deployed four T-Hawk so-called micro air vehicles (MAVs) to survey the plant from above. The MAVs, sent to Japan by Honeywell Aerospace and equipped with radiation sensors, can land and take off vertically, navigate tight spots, and hover in place while recording video. Able to fly for up to 40 minutes, the T-Hawks captured disturbing footage of the severely battered reactor buildings, with white smoke still wafting up from the twisted metal beams.

“The T-Hawk reminds us that innovative technologies initially created for defense purposes can find crucial roles in humanitarian and disaster recovery efforts,” Honeywell CEO Tim Mahoney says of the bots, which were initially developed with DARPA. That link to America’s bleeding-edge defense tech agency is significant in understanding Japan’s seemingly lackluster robotics response to the disaster. It simply didn’t have robust, experienced robot systems to tackle Fukushima, and it became apparent that the robots best suited to performing useful work at the disaster site were military robots developed overseas.

“In the case of the United States, the military invests a lot of money for this kind of robot,” University of Tokyo Engineering Professor Hajime Asama told the news agency AFP. “But in Japan, it is prohibited to make military robots.”

Japan’s war-renouncing constitution from 1947 hasn’t prevented the country from building an enormous Self-Defense Force (SDF), and that force played a vital role in the relief and recovery efforts in Tohoku after the quake and tsunamis. But a strong cultural affinity for robots, based on decades of positive images in science fiction of robots as friends and protectors, may be part of the reason that Japan has not developed its own military robots. Meanwhile, Japan has spent millions of dollars and decades of man-hours developing the Humanoid Robot Project (HRP), an anthropomorphic droid that has yet to find a practical application.

More Robots Arrive

Fortunately, Tokyo was wise enough to ask for outside help after the disaster. Honeywell’s T-Hawks spearheaded a wave of foreign robots that began arriving in Japan to help human workers struggling with the Daiichi plant. To accommodate the influx, the government designated a facility in the science city of Tsukuba, northeast of Tokyo, where bots from overseas were evaluated and Japanese workers learned to operate them. Next, they were transported farther north to J-Village, a site near the Daiichi plant that acts as a barrier between contaminated and radiation-free machines and other gear. Other entities, such as the SDF and the U.S. military, are assisting TEPCO on-site and from afar.

Another U.S. military contractor, iRobot, was one of the first to get robots into the reactor buildings. The Massachusetts-based maker of Roomba vacuum robots sent two PackBot 510 and two Warrior units to Japan, along with support staff, to assist in probing the plant. In late April, TEPCO released footage of PackBots gingerly rolling over debris on the shadowy first floor of the Unit 1 boiling-water reactor, opening and closing doors with their long retractable arms.

Operated by TEPCO staff using Xbox 360 controllers, the PackBot crawlers measured radiation, oxygen, and temperature levels inside the reactor. They logged 57 millisieverts of radiation per hour inside the building, nearly three times the safe level for a human being. The battle-hardened robots also continued to operate in 110-degree temperatures and high humidity.

Still another U.S. contractor that lent technical support to Japan is McLean, Va.-based Qinetiq North America. Qinetiq sent TALON and Dragon Runner robots to navigate through rubble and measure radiation. The TALON is a portable, remote-operated system that has been used for ordnance disposal and surveillance in Iraq and Afghanistan. The Dragon Runner, meanwhile, is a smaller, compact crawler that can operate in sewers, drainpipes, and other tight spots.

In addition to these robots, Qinetiq sent loaders manufactured by Bobcat that can be turned into unmanned vehicles with Qinetiq’s robotic appliqué kit, which allows the loaders to be controlled via laptop.

“The Japanese robotics community is fantastic at stationary robotics doing pick and place tasks, and they’re indoors, not outdoors,” says Qinetiq Vice President of Unmanned Systems Robert Quinn, who was in Japan to help train TEPCO staffers. “The reason our equipment is being used is because of the war in Iraq and the 9-11 attack on America. That attack resulted in the need for robust, outdoor systems. For 10 years, our robots have just gotten better and better, and we have 3,500 deployed with the military for outdoor operations in Iraq and Afghanistan.”

The biggest robotics challenge at Fukushima, according to Quinn, aside from the radioactivity, is communications. The reactor buildings are full of metal-reinforced concrete, which can interfere with radio signals between robots and controllers hundreds of yards away. Another issue is government approval for the use of powerful radio signals used by iRobot and Qinetiq machines, required in Japan by the Telecommunications Bureau under the Ministry of Internal Affairs and Communications. It’s unclear whether getting permission hindered deployment of the robots.

Lessons Learned
Quinn emphasizes, however, that humans are always the main players in the effort to stabilize the reactors. “Humans will be tackling this problem, and robots for the most part will assist, so that human workers can spend no more than a few minutes in this radioactive environment.”

The need to leverage technology to find solutions to the disaster at Fukushima and elsewhere in northern Japan is a lesson that Japanese roboticists have taken to heart. On March 31, they launched the Robotics Task Force for Anti-Disaster (ROBOTAD), a group of more than 30 academics and public- and private-sector experts chaired by the University of Tokyo’s Professor Hajime Asada and working with the Science Council of Japan. Including key players in the Japanese robotics community such as RoboCup co-founder Minoru Asada of Osaka University and Shigeo Hirose of the Tokyo Institute of Technology, the task force is intended “to facilitate the countermeasures of and the recovery from the disaster by employing robotics technologies to the stricken area by the earthquake and tsunami, and the site of accidents of the Fukushima nuclear power plant.”

In a statement on the group’s website, Asada discussed various robot technologies that are useful in the kind of disaster that hit northern Japan, remarking, “There still does not exist such a versatile robot that can move around obstacles such as rubble piles, protect itself from radiation, gather information about its surroundings, handle multiple tasks, and so on.” He went on to list nine abilities considered necessary for robots to operate in disaster zones, including crippled nuclear plants:

1.       Ability to withstand radiation to some extent

2.       Remote controlled from various distances, using repeaters if necessary

3.       A battery capacity of at least one to two hours

4.       Waterproof

5.       Able to navigate over rubble

6.       Can be decontaminated with water

7.       Can open or close doors

8.       Able to navigate through tight spaces

9.       Can clear rubble via remote control.

ROBOTAD has pointed to several made-in-Japan systems that would be useful in future crises. One system being discussed is Quince, a crawler with an arm mechanism similar to PackBot’s that is being developed as a common platform by the Chiba Institute of Technology, Tohoku University, and the International Rescue System Institute (IRS), a Japan-based group that deployed underwater robots to search for bodies off Tohoku following the tsunami. Equipped with a six-tread locomotion system, Quince can crawl over piles of rubble, respond to control signals from up to 1.2 miles away, and move at a top speed of about 5 feet per second. Its sensors include thermal imaging, radiation and gas monitoring, as well as standard video and camera functions. While not as rugged as the PackBot or TALON, Quince could be useful as a radiation detection and mapping robot in the event of future nuclear accidents. It will have a trial by fire, since the device is already on the ground in Fukushima. The device’s co-developer, Eiji Koyanagi of the Chiba Institute of Technology, has been helping to train the TEPCO staff that will operate Quince at the Fukushima plant.

Meanwhile, TEPCO and its partners face a massive, complex task in bringing the plant under control, reestablishing a regular cooling system, and working toward a permanent shutdown of the facility. Robots will continue to play a key role as long as radiation levels remain elevated, and that seems certain to continue for months. Japanese roboticists have a tough game of catch-up to play, and will no doubt ponder Tokyo’s past decisions to halt funding for nuclear emergency robots. It may have been more than simple shortsightedness, indeed a matter of misguided face-saving, as Hirose remarked to the Asahi Shimbun newspaper: “[The authorities] perhaps thought that people would think that they were anticipating a nuclear power plant accident if they had developed robots for accidents.”

(Photo Credit: TEPCO)