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Fukushima Reactor Backup

March 20, 2011 by staff 

Fukushima Reactor Backup, (Kyodo) – Japan ‘s Fukushima Daiichi nuclear power plant disaster has seen a steady source of electricity finally reached two of its crippled nuclear reactor buildings Sunday, a key step forward in restoring the reactor cooling functions to avoid disaster even worse.

In a sign that the current operation to cool the spent fuel tank is working, Defense Minister Toshimi Kitazawa said that the temperatures of pools in the six reactors were below 100 C. But a temporary rise in pressure in the No. 3 reactor containment revealed that authorities are still walking on thin ice to face the disaster.

Units No. 5 and 6, which were relatively less problematic than the others, realized what appelle”l’arrêt cold,”meaning that the engines have stopped safely with the temperature water inside the reactor falls below 100 C.

Chief Cabinet Secretary Yukio Edano, who held a press conference in the afternoon, was cautious about prospects, saying:’’there will be surprises, even if the process to maintain the status quo and improve the situation goes well.”

He also said that the pulp mill nuclear, which has undergone a series of explosions and fires since the deadly earthquake on March 11, is doomed to be scrapped.

But Kitazawa announcement later today on the results of temperature measurement added to better signs, as he noted that the temperatures of the upper parts of the spent fuel pools are the numbers that seraient”rassurer people.”

It’s top of the containment vessel of the No. 3 reactor is 128 C, which is said Kitazawa”dans the range of expectations.”

According to the plant operator Tokyo Electric Power Co., an external power supply reaches power installations receiving the 5 No. 2 and No. Of units in the afternoon. The company now plans to restore systems such as radiation monitoring and other data, the light control room and cooling the reactor and the reactor pool storage of spent fuel.

Alongside the work on electricity, the SDF and firefighters continued the task of imminent cooling pools of spent fuel, feared he may have been boiling, pouring thousands of tons of water in No. And No. Reactor buildings. The operation is possible because the apparent hydrogen explosions blew the roofs and walls of buildings.

The Ground Self-Defense Force shot water at the pool at the No. 4 unit of spent fuel for the first time on Sunday, both morning and afternoon, with the amount of water totaling about tons, according to the Ministry of Defence.

The ministry also plans to mobilize the GSDF two Type 74 tanks to remove the rubble of the factory, which hampers efforts to spray water. It is extremely rare to use those tanks to real missions.

A ministry official said the decision was taken because the vehicles are tight air”plus and have a great capacity for protection against radiation,”suggesting the difficult conditions under which the SDF and firefighters placed.

The Tokyo Fire Department has also pulled from the water in pool storage of spent fuel per unit No. 3 for hours.

Under the operation that began Thursday, more than 2,600 tons of water is regarded as having been paid to building No. 3, exceeding the capacity of the pool of, 400 tons. But we do not know how much water is in the pool, which is important to cool the fuel and shield radiation.

The fuel rods used in the reactor were plutonium and uranium mixed oxide fuel, called MOX, which could release highly toxic plutonium in the event of a collapse. Fuel rods are made from natural uranium.

Tension grew to a point on the situation of reactor No. 3, after the government agency Nuclear Safety said that the pressure in the containment was found to increase and it is necessary to take measures to solve the problem.

But Tokyo Electric said later that he would not take immediate action, which could result in release of radioactive steam outside, because the pressure has stabilized.

Meanwhile, a total of 40 tons of seawater is pumped into the fuel tank of the unit 2, using a source of wealth.

The radiation level inside the plant is on a downward trend. Approximately 0.5 km north-west of reactor No. 2, the level fell to 2,623 mSv per hour from 19 hours, compared to 3443 mSv / hr at 2 pm on Saturday.

The Industrial and Nuclear Safety Agency said it has confirmed the presence of radioactive iodine and cesium air inside the plant extract for the first time since the earthquake.

The concentration of iodine-131 was about times higher than the prescribed limit for workers with radiation. If a worker inhales air such, there may be a risk of internal exposure, the agency official.

But the official said that workers wear protective clothing and internal exposure has not been reported so far.

The power plant has been hit hard by the earthquake of magnitude 9.0 on the Pacific coast of Fukushima prefecture about kilometers north of Tokyo.

No. 1, No. 2 and No. 3 reactor, which operated during the earthquake, but stops automatically, lost their reactor cooling key functions because the earthquake and tsunami, which followed massive, cut electricity to the factory.

Their reactor cores are believed to have partially melted and seawater was pumped into them to avoid the fuel to be exposed.

The other No. 4, No. 5 and No. Units were undergoing maintenance at the time of the quake, but No. Is different in that all the fuel was not in the heart of the reactor, but been in the pool of spent fuel.

The pool No. 4 unit of fuel has also lost its function of cooling and fire erupted twice.

Source: http://e.nikkei.com/e/fr/tnks/Nni20110320D20NY323.htm

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