Packbots explore stricken reactor

iRobot devices gather data on radiation

A radio-controlled iRobot PackBot is shown opening a door at the Fukushima Daiichi power plant yesterday in Japan. A radio-controlled iRobot PackBot is shown opening a door at the Fukushima Daiichi power plant yesterday in Japan. (Tokyo Electric Power Company via AP)
By D.C. Denison
Globe Staff / April 19, 2011

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Two robots made by iRobot Corp. of Bedford explored buildings inside Japan’s damaged nuclear reactor Sunday and sent back data that indicated radiation levels are still too high to allow human repair crews to go inside.

The robots, military models called PackBots, were donated to Japan by iRobot shortly after the Fukushima Daiichi nuclear power station was crippled by the March 11 earthquake and tsunami.

On Sunday, Tokyo Electric Power Co., which owns the damaged reactor, put the two PackBots to work. After a plant worker opened an outer door to one of the buildings, one of the robots opened an inner door, and the two PackBots rolled in on their tank-like treads.

Once inside, the robots took readings for radioactivity, temperature, and oxygen. They entered another building later, and a third yesterday.

Sensors on the robots reported radioactivity readings that were too high to allow humans to enter either of the buildings explored Sunday. Data from the building entered yesterday have not yet been analyzed.

The high radiation could slow down repair of the reactor. Larger robots can remove some debris, but human workers must perform the electrical repairs needed to restore the cooling systems.

The 60-pound iRobot PackBots are equipped with cameras and a variety of sensors to enable unmanned surveillance of potentially dangerous areas. A flexible arm allows the unit to pick up items and operate simple doorknobs and latches. The robots can be controlled remotely by radio or through a fiber-optic cable that unwraps from a spool mounted on the machine.

IRobot has sold about 3,500 PackBots since late 2000; many are used by the American military in Iraq and Afghanistan, primarily for bomb detection and disposal. PackBots were also used to sort through debris follow ing the Sept. 11, 2001, terrorist attacks on the World Trade Center in New York.

IRobot also sent a six-person training team to Japan for two weeks, as well as two larger robots called 710 Warriors, but the Tokyo power company has not released news of their deployment.

British defense contractor QinetiQ Group PLC, which has a plant in Waltham, has sent six mobile robots to the Japanese government, ranging from lightweight surveillance machines to heavy construction vehicles. All are intended to allow workers to repair the reactors from a safe distance.

The robots were designed and built at the former Foster-Miller Inc. plant in Waltham. QinetiQ bought the company in 2004.

“Right now, our robots are being integrated into a mobile command and control center for long-term use,’’ said Bob Quinn, vice president of unmanned systems, QinetiQ North America, who returned to Boston last week after spending 28 days training workers in Japan.

“QinetiQ robots will be used primarily to remove highly contaminated debris and move in shielding blocks so that humans will be able to work on the site without extended radiation exposure,’’ Quinn said.

Japan is a world leader in robotics, but the country’s robot makers mostly build stationary industrial machines for use on assembly lines, rather than mobile rescue or surveillance robots.

Indra Purkayastha, senior vice president of product development at iRobot, said that the PackBot’s controllable arm has proven to be valuable to the Japanese.

“Much of our training in Japan was focused on using the PackBot to open doors, which the operators were able to do on Sunday,’’ he said. “The PackBot is designed to be first responder on dirty and dangerous missions, so we are very proud that they are being put to use.’’

Material from Globe wire services was used in this report. D.C. Denison can be reached at

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