|Image: Tokyo Electric Power Co's Fukushima Daiich|
The company says it cannot know for sure what is happening in many cases because it is too dangerous for workers to get close to some reactors.
So far the highest radiation level measured at Fukushima Daiichi plant was 1,000 mSv/h on March 16, 2011 after smoke rose above the plant and staff were briefly evacuated. When radiation was coming down to 800–600 mSv/h, staff returned. The typical dose near Chernobyl reactor 4 and its fragments, shortly after explosion was ≈ 10 000–300 000 mSv/hr.
Robots will take over at Fukushima Daiichi Plant
|Credit: RAD Rover/CMU|
Three Mile Island Robots
After the Three Mile Island Unit 2 (TMI-2) nuclear plant disaster in 1979, that destroyed much of the reactor core and left large areas of the reactor containment building inaccessible to humans, several robot prototypes made their debut in the recovery and clean up. William "Red" Whittaker, a robotics professor at Carnegie Mellon University, assembled a team of students in the 1980s to build three robots designed to help inspection and clean up the basement of a damaged reactor at TMI-2. The RAD Rover (1983) was the first vehicle to enter the basement of TMI after the meltdown in March 1979. This vehicle worked four years to survey and clean up the flooded basement. The CoreSampler (1984) drilled core samples from the walls of the Three Mile Island basement to determine the depth and severity of radioactive material that soaked into the concrete at the site.
Nuclear Power Plant Robots in Japan
In Japan general-purpose robots for inspection and maintenance at nuclear power plants have been developed since early 80-ies by Japanese companies such as Toshiba, Hitachi and Mitsubishi. (2)
Chernobyl Disaster Robots
The Chernobyl disaster in 26 April 1986 at the Chernobyl Nuclear Power Plant in the Ukrainian SSR (now Ukraine), was so far the worst nuclear power plant accident in history, and it is the only one classified as a level 7 event on the International Nuclear Event Scale.
|Credit: CMU Pioneer Robot|
Nuclear Decommissioning Robots
According to the World Nuclear Association, WNA, in October 2010 about 100 mines, 80 commercial power reactors, 45 experimental or prototype reactors, over 250 research reactors and a number of fuel cycle facilities, have been retired from operation. Some of these have been fully dismantled. In the UK alone it is estimated that the total cost of dealing with the nuclear legacy is nearly $100Bn. The UK government and the Nuclear Decommissioning Authority (NDA) have developed robots that took over in 2008 from human staff to dismantle the uranium fuel reprocessing plant at Dounreay. The plant was too contaminated with radiation for human workers to carry out the work, so the site turned to specialist demolition firm Brokk to supply the remotely-operated equipment that can work inside cells and a pond. (1)
Applied Robotics for the Power Industry
The IAEA booklet Ten Years after Chernobyl: What do we really know? attempts briefly to bring to light what has been learned after ten years of examining the consequences of the Chernobyl accident, reviewing both its immediate and long-term human health and environmental impacts. It is based principally upon the results of an international conference, "One Decade After Chernobyl: Summing Up the Consequences of the Accident," which brought together more than 800 experts from 71 countries in Vienna in April 1996 under sponsorship of the European Commission (EC), the World Health Organization (WHO) and the IAEA.