Saturday, March 19, 2011

TEPCO accelerates its efforts to cool the reactor

Tepco Japanese company responsible for nuclear plants affected, has accelerated its efforts to restore electricity that powers the cooling system of Fukushima Daiichi plant while continuing to release water to the reactor 3. TEPCO hopes to feed electricity to pump the cooling water system to two reactors, but the start-up will not be immediate, as the teams need to be reviewed earlier, the company said.

In a statement, the company has said that this move "will provide power to Unit 2 first and then the reactors 1, 3 and 4, because 2 is expected to be less damaged." The cooling system is intended to lower the temperature of the spent nuclear fuel pools, and today will focus on units 1 and 2.

Nuclear Security Agency of Japan reported that it expects to install the cables that feed the cooling of the reactors 1 and 2, while the operation to restore the system in units 3 and 4 can be completed on Sunday. The temperature increase in the pools of spent nuclear fuel storage reduces the water level remains stable rods of radioactive material, with the risk of melting and massive release of radiation.

Also, at 7 am (23.00 hours in Spain) a team of the Tokyo fire department released 90 tons of water for 20 minutes to the reactor 3 to try, for the third consecutive day, the fuel pool cooling unit. After checking pumps and other equipment works, TEPCO would try to restore damaged spots, setting their priority in the cooling of the reactors.

This equipment includes the injection of seawater, a reservation system fluid control and a control rod. The release of water in Block 3 of the Japanese nuclear plant in Fukushima reduced some of the pressure in the reactor chamber, according to the latest report from the Japanese nuclear safety agency NISA.

However, in the other two blocks, which were turned off automatically after the quake a week ago, released values showed a slight upward trend. Another measure taken by TEPCO has been drilling the tops of the reactors 5 and 6 to prevent hydrogen explosions. "Due to fears of an accumulation of hydrogen in the reactors 5 and 6, TEPCO has drilled three holes from 3 to 7.5 inches from the roofs of their offices," said a company spokesman.

Units 5 and 6 are the least damaged of the plant, since, unlike reactors 1 to 4, the cooling systems were able to continue working after the earthquake and tsunami. Hours after raising the level of nuclear alert in Japan from 5 to 6 on a scale of 7, the International Energy Agency (IAEA), wanted to send a nod to the hope ensuring that the situation in central Fukushima suffered no "A significant worsening" and that units 1, 2 and 3 of the complex "appear to be quite stable." However, the scientific advisor to the UN nuclear agency, Andrew Graham, said the situation remains "very serious." However, the expert acknowledged that there is "great concern" about the situation in spent fuel pools of units 3 and 4 of the plant, without giving further details.

"We are moving towards a stable situation that does not change, which is positive. It is true that half the fuel (used) is not covered with water, which is bad. But at least the water levels in Units 1, 2 and 3 are stable, "said Andrew. The increase of alert coincides with the analysis of the Japanese authorities, who also gained a degree in the alert level, in this case from 4 to 5, which equates to Fukushima to the incident at Three Mile Island (1979), the second most serious nuclear incident in history after the Ukraine's Chernobyl plant in 1986, which is the only case so far in the world of top-level major accident.

To prevent a worsening of the situation, local authorities have several fire trucks that have started to shoot 50 tonnes of water onto the pool which houses the fuel rods from the reactor 3, after Thursday Air Force helicopters poured up to 64 tons of water to try to control the temperature of the reactor that most worries the authorities.

This is an unprecedented mission, according to the spokesman of the International Atomic Energy Agency, Yukiya Amano, to cool the reactor, while trying to revive the external electric power cables and generators to help the cooling system. Moreover, since the foreign aid is also organized.

France this weekend send a shipment with robots, among other things, to help control the leakage of the plant. This machine is equipped with bulldozers or excavators and can perform complex technical gestures as material extraction or recovery of waste as well as carrying out radioactivity measurements and take pictures and transmit them.

For its part, Renate Czarwinski, IAEA radiation expert, said the radiation doses recorded in the disaster area have declined substantially in recent days. For example, in Tokyo, located 230 kilometers from Fukushima, the measured radiation has fallen from a peak of 0.5 per hour microsieverts March 15 to less than 0.1 two days later.

Microsieverts exposure to 100,000 per year is the threshold accepted by the experts to consider a clear risk of developing cancer. Andrew said that with the levels recorded in the Japanese cities for now there is no risk to human health, "unless the situation worsens dramatically."

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