Thursday, April 7, 2011

Japan uses nitrogen to avoid an explosion in Fukushima

Technicians of the nuclear Fukushima (northeastern Japan) started, Thursday, April 7, injecting nitrogen to avoid an explosion in a damaged reactor and prevent a worsening of the nuclear accident since Chernobyl's largest there are twenty-five years. The president of Tokyo ElectricPower Company (TEPCO), operator of the Fukushima nuclear plant damaged by the earthquake and tsunami of March 11 in Japan, returned to work.

Masataka Shimizu was hospitalized in March for overwork. But he returns to the front of the stage in a still very delicate. Nearly four weeks after the devastating earthquake and tsunami especially giant that has devastated the Pacific coast north of Tokyo, the crisis in Fukushima Dai-Ichi is far from settled.

Plumes of white smoke, probably from the radioactive water vapor, continue to escape from three of the four reactors injured. The fuel rods in the heart of the reactor and the cooling pools must be watered day and night using emergency pumps, until power and cooling systems are restored.

To prevent further explosion on the site, TEPCO has decided to invest preventively in nitrogen in the reactor 1, wherein the hydrogen accumulated in large quantities. The first two explosions, which occurred on 12 and 14 March at Units 1 and 3, had indeed been caused by the ignition of this gas with oxygen.

Inert, nitrogen is commonly used in storage areas susceptible to falling oxygen levels in air and thus replace a portion of the atmosphere. The operation of "inert" is expected to last six days for a total of 6 000 m3 of nitrogen injected, according to TEPCO, which intends to apply the same treatment to reactors 2 and 3 in the coming days.

No new reactor water leak in the nearby ocean has been found, said on Thursday, the Nuclear Safety Agency, after successfully filling a gap in a pit in which escaped from the water highly radioactive. But the risk of contamination of the marine environment is not so far ruled out, experts said.

The deliberate discharges at sea of 11 500 tons of slightly radioactive water, according to TEPCO, continued for the fourth consecutive day in front of the station. The evacuation of this water into the ocean, where radio-elements are intended to be diluted, is needed to free up storage tanks intended to be filled with highly radioactive water.

It has accumulated in the facilities and technical galleries of reactors 2 and 3. This polluted water contains in particular the 131, whose radioactivity is reduced by half every eight days, and especially cesium 137, which remains active for decades. But the seafood is the staple food for Japanese and Japanese, very demanding on food safety, may no longer consume if there is a health risk.

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