Five years later, Fukushima remains a huge challenge for Japan
March 11 2016 Le Figaro
GRAPHICS / VIDEO - The March 11 2011, a powerful earthquake struck Japan, triggering a tsunami and a nuclear accident including the assessment of consequences is not complete. Five years later, hundreds of thousands of people remain exiled and technical means to clean the center and the irradiated areas remain to imagine.
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Five years after Fukushima, the accident is still ongoing
By Ludovic Dupin Usine Nouvelle on March 11 2016
Japan collects on the fifth anniversary of the tsunami of March 11 2011 and nuclear accident he caused. On the Fukushima site, work continues because the three damaged reactors are barely under control.
The March 11 2011, an earthquake and tsunami hit Japan. Flooding in the Fukushima causes loss after another for power and water supply. The hearts are warming, eventually bursting into releasing massive amounts of hydrogen. Gas explodes, ripping three of the six reactors on the site.
Since then, the operator TEPCO is working to stabilize the situation of the site for its dismantling. "Five years after the accident, efforts continue to control facilities in a persistently difficult environment linked to a still limited knowledge of the state of the reactors and damaged buildings"Judge Institute of Radiation Protection and Nuclear Safety (IRSN) in an information note compiling the state of knowledge.
He adds : "The groundwater pollution due to containment barriers degradation always leads to diffuse radioactive releases into the environment".
always fuel cooling
"The reactors 1, 2 3 and are maintained at a temperature between 20 ° C and 50 ° C by injection of about 5 cubic meters per hour of fresh water per reactor", ensures SNRIs which states that a nitrogen injection is maintained within the containment to avoid further risk of explosion.
Swimming pools, in turn, are cooled by a closed water circuit in order to stay below 30 ° C. Emptying the spent fuel they contain should have started from 2015, but Tepco had to postpone these operations. "The withdrawal of fuel present in the pools (provided) from 2017 for the pool of reactor No. 3, 2020 from those for reactor No. 1 and 2 No." reports IRSN.
As for the withdrawal of fuel in the reactors degraded, it is anticipated that between 2020 and 2025. The note states that these deadlines are to be considered as indicative as many characterization work of the state of the facilities are still needed.
contaminated water volumes of accumulating
For five years, the work on the management of contaminated water - the water used for cooling cores and the end of the natural runoff - is the first fight. "The volume of water accumulated in storage tanks and basements of buildings to reach early 2016 900 000 near cubic meters" IRSN reports, the equivalent of 300 Olympic swimming pools.
Part of this water has been treated to extract the cesium and strontium. Even if there are traces of radioactivity, primarily tritium, Tepco expects a discharge authorization of these waters. According IRSN, Tepco today would have a storage capacity of 1 million cubic meters.
In addition to these water stored in about 3 000 containers, Tepco must also manage about 70 000 cubic meters of heavily irradiated water in basements rough buildings. "In addition, they suffer significant water inflows (about 200 m3 / day) from the table," added the IRSN.
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