An unexpected failure in a second reactor Fukushima aggravates
Japanese authorities confirmed that the reactor 3, in addition to 1, has been affected by the failure of the cooling system after the earthquake on Friday .- It the worst nuclear accident since Chernobyl .- Up to 160 people may have been exposed to radiation .- 200,000 people have been evacuated in the area.
Japan, nuclear country model, an example of use of nuclear technology even in the worst seismic zone in the world, living nightmare days pending central I Fukushima, 240 kilometers from Tokyo. After the earthquake and Friday tsunami, nuclear lost yesterday and cooling system for more than 24 hours outside released radioactive gases to reduce pressure inside and avoid an even greater disaster. The nuclear safety agency Japanese described the accident as level 4 on the scale of atomic events (INES, ranging from 0 to 7). This makes it the worst nuclear accident since Chernobyl -in 1986 and qualified as a level 7 - and the fifth worst civilian incident in history.The situation seems complicated at times. As teams struggle to cool the plant by injecting sea water, the authorities have confirmed this night that the reactor 3 has also been affected after the initial breakdown of the number 1, by failing to operate the emergency cooling system. The experts consulted did not rule that could melt the heart of the nuclear, but evolution is uncertain and information inaccurate. Fukushima
is not Chernobyl, at least until now, but yes closest thing has been to Three Mile Island , the 1979 accident in Harrisburg (Pennsylvania, USA). This was a level 5 on the INES scale, "accident with broad implications." Then the lost central cooling system and the uranium core melted. The incident halted during more than 30 years of nuclear construction in the U.S..
Japan has 54 nuclear in 18 sites totaling 47,000 megawatts of installed capacity. The atom marked the last year 29% of the country's electricity. In Spain, with 7,728 megawatts installed nuclear, that percentage is 21%.
clock Anti
Friday's quake, of 8.9 magnitude on the Richter scale, was too much for the central Fukushima I, owned by Tokyo Electric Power (TEPCO) and whose first reactor opened in 1971. Reactors 1, 2, and 3 stopped automatically by the earthquake. The other three of the huge nuclear complex on the coast were in maintenance.
By fall the electrical system, also turned off the cooling system of the plant. In a nuclear heat must be removed continuously from the reactor, which is achieved with various systems of water circulation. After the earthquake, were put in place emergency diesel generators, there are usually four to pump ground-water cooling. But an hour after the tsunami struck and disabled the emergency cooling also.
A nuclear plant is like a Russian doll: The reactor vessel of metal, surrounded by the containment building, with concrete walls and steel-which, in turn, is covered by the reactor building, in this case a bucket of cement.
With poor cooling, "in the kernel started up the pressure" by the accumulation of radioactive gases, as explained nuclear physicist Manuel Fernández Ordóñez. The plant began opening relief valves to release gases into the containment. "By making a simple analogy, imagine that the reactor core is like a pressure cooker. If the pressure gets too high you have to open the valve, releasing gas into the kitchen, which is the containment building, but not to the abroad, "said Fernandez Ordóñez.
Still, the pressure in the containment building continued to rise. "Containment is at a lower pressure than the outside so that if there is a crack, do not leave anything out. The normal pressure is 400 kilopascals within and abroad is 1,000. In the central pressure rose to 600 and then 850. So they decided to open outwards and remove the contaminated gas. but it always comes out is filtered radioactive steam. "
first Japanese authorities ordered evacuations from towns within a radius of three kilometers of the plant, then 10 and finally 20 km. Gauges reflected radiation outside the spill. At four am (Japan time) the registered foreign natural radiation microsievert 0.07 per hour. At 15.29, the survey was of 1,015 microsievert / hour, 14,500 times, and then began to decline.
fatal explosion
If the information came from Fukushima was confusing all worsened to 15.36 (07.36 CET the English), when an explosion rocked the plant and saw the smoke for miles. The specter of Chernobyl went around the world. The Japanese agency nuclear safety (NISA) said later that the explosion had not affected the building containment, although it had been part of the roof and wall of the reactor building. Japan claimed that the explosion of the hydrogen released exploded.
occurred during times inaccurate information about the cooling, if TEPCO had managed to connect, if you had gone ... Radiation Protection Director Nuclear Safety Council (CSN), Juan Carlos Lentijo, summarized in the afternoon: "The situation is dire but the unit is holding. That yes, they have to refrigerate it or can get out of control". Radioactive discharges Lentijo justified: "Better a nice little unloading is to have a dramatic failure. "
Five hours after the explosion, the Japanese authorities attempted a desperate option: nuclear cooling seawater directly and boric acid, a substance that absorbs neutrons.
spokesman Government of Japan, Yukio Edan, said that this was a method of "unprecedented" and said they were preparing to deliver iodine to the population. "Iodine is an emergency protective measure against possible radioactive cloud, which has iodine. The iodine saturated thyroid gland and prevents the radioactive iodine to act, "said Lentijo. The agency Kyodo reported that there were three hospitalized patients who had received high doses of radiation. Under NISA, the number of people exposed to radiation at Fukushima I could be between 70 and 160.
Experts warned that if Japan could not cool the plant could result in a fusion core. If you run out of water reactor, the uranium used for fuel is based on a sort of magma, as happened in the U.S. in 1979. If the containment building would fail the consequences much more tragic. Nuclear Forum chairperson, Maria Teresa Dominguez, admitted that the meltdown was possible, but stressed: "The most important not to damage containment. "
atomic energy Criticism
Apart from the implications for Japan, Fukushima accident likely to affect the nuclear industry in the world. With fading memories of Chernobyl, the nuclear lobby was getting to turn public opinion in favor of the nuclear option as a way to reduce oil dependency. Domínguez rejected that will affect the future: "In an unprecedented disaster headquarters worked perfectly. What it has failed as expected. "Another industry source used another argument: "Trains have also been lost in the tsunami and no one would think that affects the railway."
Environmentalists charged itself against nuclear power. Jan Beranek, head of Greenpeace's nuclear campaign, summed : "The industry says that these events can not occur in modern reactors (...), but nuclear power is vulnerable to the potentially lethal combination of human error design failures and natural disasters. "
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