A draft investigation report into the 2011 Fukushima nuclear meltdown, adopted by Japanese nuclear regulators Wednesday, says it has detected dangerously excessive ranges of radioactive contamination at two of the three reactors, including to considerations about decommissioning challenges.
The interim report stated knowledge collected by investigators confirmed that the sealing plugs sitting atop the No. 2 and three reactor containment vessels have been as fatally contaminated as nuclear gasoline particles that had melted and fell to the underside of the reactors following the March 2011 tsunami and earthquake.
The consultants stated the underside of the sealed plug, a triple-layered concrete disc-shaped lid 12 meters (39 toes) in diameter sitting atop the first containment vessel, is coated with excessive ranges of radioactive Cesium 137.
The No. 1 reactor lid was much less contaminated, presumably as a result of the plug was barely knocked misplaced and disfigured as a result of influence of the hydrogen explosion, the report stated.
This Jan. 31, 2014, picture launched by Tokyo Electric Power Company Holdings exhibits the aerial view of the No. 3 reactor, with its roof blown off and protect plug (circle within the center) uncovered, in Okuma city, Fukushima prefecture, northeastern Japan. (Tokyo Electric Power Company Holdings through AP)
The consultants measured radiation ranges at a number of areas contained in the three reactor buildings, and examined how radioactive supplies moved and security gear functioned in the course of the accident. They additionally stated venting try at Unit 2 to stop reactor injury by no means labored, and that security measures and gear designs nonetheless should be examined.
The lid contamination doesn’t have an effect on the surroundings because the containment vessels are enclosed contained in the reactor buildings. The report didn’t give additional particulars about if or how the lid contamination would have an effect on the decommissioning progress.
Nuclear Regulation Commission Chairman Toyoshi Fuketa known as the findings “extremely serious” and stated they might make melted gasoline elimination “more difficult.” He stated determining tips on how to take away the lids can be a serious problem.
Removing an estimated 900 tons of melted gasoline particles from three reactors is a frightening job anticipated to take many years, and officers haven’t been capable of describe precisely when or the way it could finish.
The Fukushima plant was to start out eradicating melted gasoline particles from Unit 2, the primary of three reactors, later this 12 months forward of the tenth anniversary of the accident. But in December, plant operator Tokyo Electric Power Co. and the federal government introduced a delay till 2022. They stated the event of a robotic arm for the particles elimination — a joint mission with Britain — has been delayed as a result of pandemic.
Under the present plan, a remote-controlled robotic arm might be inserted from the facet of the reactor to achieve the molten gasoline combined with melted elements and concrete ground of the reactor. Eventually the lids additionally must be eliminated, however their contamination is a serious setback.
The group of consultants entered areas contained in the three reactors that have been beforehand extremely contaminated and inaccessible after radiation ranges got here down considerably. They’re in search of knowledge and proof earlier than they get misplaced within the cleanup.
Massive radiation from the reactors has brought about some 160,000 folks to evacuate from across the plant. Tens of 1000’s are nonetheless unable to return residence.
