The crisis in the Fukushima Daiichi Nuclear Power Station (Fukushima No. 1) remains "very serious." As said Thursday a spokesman for the International Atomic Energy Agency (IAEA), although the situation has worsened significantly since Wednesday, it has increased the radioactivity in the evacuation zone around the plant.
Indeed, high levels of radioactivity within the plant are hampering efforts to cool the reactor and return the power to Fukushima. In some localities that are within 30 miles of the plant in Fukushima, pollution has "increased significantly" in the last 24 hours, with levels up to 0.17 mSv per hour (exposure to 100 mSv per year is the threshold accepted by the experts to consider a clear risk of cancer), said Andrew Graham, special adviser to the director of the IAEA, Yukiya Amano, scientific and technical issues.
Amano has come out on Thursday heading to Japan to discuss the situation on the ground. According to Andrew, the IAEA receives radiation data from 47 Japanese cities including Tokyo, where pollution levels are still below levels dangerous to humans. "The current situation in the Fukushima Daiichi plant remains dire ...
[but] there has been a significant deterioration since yesterday," said Andrew. "The situation is relatively stable. Has not deteriorated, which is positive. But you can always get worse, "he said. According to Andrew, the" greatest security concern "is now on the reactor 4 of the plant, which has an alarming warming in the pool that hosts the spent nuclear fuel.
On Tuesday, the pool temperature was 84 ˚ C, normal is 25 ° C. It is unknown temperature has been achieved in the last two days, but IAEA experts do not rule out that since then has started to boil. Although this reactor did not arouse concern in the beginning (he was stopped for maintenance when the earthquake hit Friday and did not contain the reactor core fuel), a hydrogen explosion and two fires have damaged the facility, leaving at a critical stage in the pool that houses the spent material.
As it is necessary to avoid heating fuel nuclei (which are now trying in reactors 1, 2 and 3, the three that work when the earthquake struck, the six who has the central), it is necessary to keep cool the spent material, because if it is heated and emits damaged and radioactive substances.
In fact, it is believed that the extremely high levels of radioactivity have been detected in the vicinity of Unit 4 are due to state pool. On Wednesday, the U.S. nuclear official, Gregory Jaczko, went on to say that the pool is completely empty. TEPCO, the company that operates the plant, has denied it, but what is clear now is that the pool is heavily damaged and spent nuclear fuel is exposed and suffering damages.
According to the latest information on Japan's government, in Unit 4 have been recorded radioactivity levels of 100 millisieverts per hour. In the 3-reactor whose pool is also warming and also suffers major damage in the containment structure, "there have been levels of 400 millisieverts per hour.
These values \u200b\u200bof radiation is causing many difficulties for workers carrying out recovery work of the nuclear plant. The highest exposure rate, a worker may remain in the area within 40 minutes, according to the World Nuclear Association. Two plant workers have gotten sick so far, according to the IAEA.
According to Elena Buglova, head of the Emergency and Incident center of the body, diseases are not due only to radiation but possibly also to the explosions at the plant. The tasks in the nuclear plant cooling are now focusing on both pools and restore electricity in the plant. On Thursday, for the first time four army helicopters poured water sea japonéshan borated on reactors 3 and 4 of the plant.
At the end of the day, five army trucks also went into action to try to cool the pools. "The only possible way to stabilize the water situation," he remarked Olivier Gupta, director of the French Nuclear Safety Authority (ASN). In the two pools, and within units 1, 2 and 3 - is key "to provide water in quantity, by all means, to maintain, do increase the level." Meanwhile, engineers working on getting the plant late in the day to connect a power cable to the reactor 2, but have not yet returned the flow of energy to the plant.
"They plan to reconnect the power [electric] to unit 2 once it has completed the irrigation water on the reactor 3," the IAEA said in a statement. Throughout the day, the workers tried to connect a cable of 1 km in length to the main network, to re-start the water pumps that cool the reactor 2.
"The preparatory work has not gone so far as fast as we'd hoped," admitted a spokesman for TEPCO, the company that operates the plant. High levels of radioactivity at the plant, often forced to control workers. Not even if you can establish energy Tepco, it is unclear whether the cooling system work, it may have been damaged by natural disasters and explosions.
Since last Friday, Japan was shaken by an earthquake and tsunami and the tsunami, we lost all power inside and outside in the reactors of the plant. Failing emergency systems, the problems of the nuclear plant. The cores of the three reactors were in operation on Friday (1, 2 and 3) are damaged, but according to the IAEA are now "relatively stable." In units 1 and 3 (the latter, the only one using a mixed oxide fuel of uranium and plutonium, MOX) fuel rods (measuring nearly four feet long) are covered by water only halfway.
Meanwhile, in the reactor 2 the liquid level is slightly higher but is discovered. Nuclear fuel must be covered with coolant to keep warm. If not, the bars that contain nuclear material (uranium or, in the case of 3, also plutonium) begin to 'melt' until there is a meltdown, with major releases of radioactivity.
It is feared that in some reactors and may have initiated partial melting of the core. Explosions and fires have occurred in Fukushima Daiichi since the earthquake. The day after the earthquake, the first explosion occurred at the plant, in reactor number 1 (the first was heat problems and high pressure), which apparently only caused damage to the building.
Early Sunday to Monday, was the No. 3 reactor which registered a hydrogen explosion. Two nights ago, reactor number 2 suffered a new explosion (at 6.10 on Tuesday in Japan, 2210 hours on Monday in the Peninsula). A few minutes later, an explosion occurred in 4 and three hours later, declaring a fire in this building.
On the night of Tuesday to Wednesday, were again the reactors 3 and 4, which showed problems. In the case of reactors 2 and 3, the damages seem particularly important. Recognized as Nipponese authorities Tuesday to the IAEA, the primary containment structure (a structure of steel and concrete prepared to stop a possible radioactive leak) of 2 was damaged and you may also have damage to the reactor vessel.
Unit 3 appears to suffer similar damage. 
Indeed, high levels of radioactivity within the plant are hampering efforts to cool the reactor and return the power to Fukushima. In some localities that are within 30 miles of the plant in Fukushima, pollution has "increased significantly" in the last 24 hours, with levels up to 0.17 mSv per hour (exposure to 100 mSv per year is the threshold accepted by the experts to consider a clear risk of cancer), said Andrew Graham, special adviser to the director of the IAEA, Yukiya Amano, scientific and technical issues.
Amano has come out on Thursday heading to Japan to discuss the situation on the ground. According to Andrew, the IAEA receives radiation data from 47 Japanese cities including Tokyo, where pollution levels are still below levels dangerous to humans. "The current situation in the Fukushima Daiichi plant remains dire ...
[but] there has been a significant deterioration since yesterday," said Andrew. "The situation is relatively stable. Has not deteriorated, which is positive. But you can always get worse, "he said. According to Andrew, the" greatest security concern "is now on the reactor 4 of the plant, which has an alarming warming in the pool that hosts the spent nuclear fuel.
On Tuesday, the pool temperature was 84 ˚ C, normal is 25 ° C. It is unknown temperature has been achieved in the last two days, but IAEA experts do not rule out that since then has started to boil. Although this reactor did not arouse concern in the beginning (he was stopped for maintenance when the earthquake hit Friday and did not contain the reactor core fuel), a hydrogen explosion and two fires have damaged the facility, leaving at a critical stage in the pool that houses the spent material.
As it is necessary to avoid heating fuel nuclei (which are now trying in reactors 1, 2 and 3, the three that work when the earthquake struck, the six who has the central), it is necessary to keep cool the spent material, because if it is heated and emits damaged and radioactive substances.
In fact, it is believed that the extremely high levels of radioactivity have been detected in the vicinity of Unit 4 are due to state pool. On Wednesday, the U.S. nuclear official, Gregory Jaczko, went on to say that the pool is completely empty. TEPCO, the company that operates the plant, has denied it, but what is clear now is that the pool is heavily damaged and spent nuclear fuel is exposed and suffering damages.
According to the latest information on Japan's government, in Unit 4 have been recorded radioactivity levels of 100 millisieverts per hour. In the 3-reactor whose pool is also warming and also suffers major damage in the containment structure, "there have been levels of 400 millisieverts per hour.
These values \u200b\u200bof radiation is causing many difficulties for workers carrying out recovery work of the nuclear plant. The highest exposure rate, a worker may remain in the area within 40 minutes, according to the World Nuclear Association. Two plant workers have gotten sick so far, according to the IAEA.
According to Elena Buglova, head of the Emergency and Incident center of the body, diseases are not due only to radiation but possibly also to the explosions at the plant. The tasks in the nuclear plant cooling are now focusing on both pools and restore electricity in the plant. On Thursday, for the first time four army helicopters poured water sea japonéshan borated on reactors 3 and 4 of the plant.
At the end of the day, five army trucks also went into action to try to cool the pools. "The only possible way to stabilize the water situation," he remarked Olivier Gupta, director of the French Nuclear Safety Authority (ASN). In the two pools, and within units 1, 2 and 3 - is key "to provide water in quantity, by all means, to maintain, do increase the level." Meanwhile, engineers working on getting the plant late in the day to connect a power cable to the reactor 2, but have not yet returned the flow of energy to the plant.
"They plan to reconnect the power [electric] to unit 2 once it has completed the irrigation water on the reactor 3," the IAEA said in a statement. Throughout the day, the workers tried to connect a cable of 1 km in length to the main network, to re-start the water pumps that cool the reactor 2.
"The preparatory work has not gone so far as fast as we'd hoped," admitted a spokesman for TEPCO, the company that operates the plant. High levels of radioactivity at the plant, often forced to control workers. Not even if you can establish energy Tepco, it is unclear whether the cooling system work, it may have been damaged by natural disasters and explosions.
Since last Friday, Japan was shaken by an earthquake and tsunami and the tsunami, we lost all power inside and outside in the reactors of the plant. Failing emergency systems, the problems of the nuclear plant. The cores of the three reactors were in operation on Friday (1, 2 and 3) are damaged, but according to the IAEA are now "relatively stable." In units 1 and 3 (the latter, the only one using a mixed oxide fuel of uranium and plutonium, MOX) fuel rods (measuring nearly four feet long) are covered by water only halfway.
Meanwhile, in the reactor 2 the liquid level is slightly higher but is discovered. Nuclear fuel must be covered with coolant to keep warm. If not, the bars that contain nuclear material (uranium or, in the case of 3, also plutonium) begin to 'melt' until there is a meltdown, with major releases of radioactivity.
It is feared that in some reactors and may have initiated partial melting of the core. Explosions and fires have occurred in Fukushima Daiichi since the earthquake. The day after the earthquake, the first explosion occurred at the plant, in reactor number 1 (the first was heat problems and high pressure), which apparently only caused damage to the building.
Early Sunday to Monday, was the No. 3 reactor which registered a hydrogen explosion. Two nights ago, reactor number 2 suffered a new explosion (at 6.10 on Tuesday in Japan, 2210 hours on Monday in the Peninsula). A few minutes later, an explosion occurred in 4 and three hours later, declaring a fire in this building.
On the night of Tuesday to Wednesday, were again the reactors 3 and 4, which showed problems. In the case of reactors 2 and 3, the damages seem particularly important. Recognized as Nipponese authorities Tuesday to the IAEA, the primary containment structure (a structure of steel and concrete prepared to stop a possible radioactive leak) of 2 was damaged and you may also have damage to the reactor vessel.
Unit 3 appears to suffer similar damage.
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