Robots investigate Fukushima reactors

18 April 2011

Tokyo Electric Power Co (Tepco) has used remote-controlled robots to assess the conditions inside the damaged reactor buildings of units 1, 2 and 3 at the Fukushima Daiichi nuclear power plant.


Yesterday, the company used two PackBot ground robots from US company iRobot to take photographs within the reactor buildings of units 1 and 3. The robots also took measurements of radiation, temperature, humidity and oxygen levels in the buildings. Today, one of the robots was sent into the reactor building of unit 2.



PackBots in Fukushima Daiichi
The PackBots make their way into the reactor building of unit 3 at Fukushima Daiichi (Image: Tepco)




While data for unit 2 has yet to be released, the measurements taken by the robots indicated that radiation readings in unit 1 were between 10 and 49 millisieverts per hour and between 28 and 57 millisieverts per hour in unit 3.


The international standard for worker exposure to radiation is 500 millisieverts per year for emergencies, while a temporary limit of 250 millisieverts per year has been allowed by Japanese authorities in the current situation.


Tepco said that oxygen levels in the reactor buildings of units 1 and 3 were about 21%, high enough for workers to enter the buildings.


Based on the data obtained by the robots, Tepco will determine what kind of work could be safely conducted by workers inside each of the reactor buildings.


Meanwhile, a remote-controlled excavator and transporter are being used to clear debris around the Fukushima Daiichi site. In addition, an unmanned helicopter is being used to film the outside and upper sections of the damaged reactor buildings.


Researched and written

by World Nuclear News