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Showing posts with label Fukushima. Show all posts
Showing posts with label Fukushima. Show all posts

Monday, March 12, 2012

Fukushima nuclear meltdown - one year later

GLOBAL TRENDS By MARTIN KHOR
 
As the world marks the first anniversary of Japan’s triple tragedy, lessons are still being drawn from the Fukushima nuclear accident and the dangers of nuclear power plants.

 IT’S been a full year since Japan’s triple disaster of earthquake, tsunami and nuclear meltdown, and the reverberations are still being felt.

The tsunami on March 11, 2011, caused around 19,000 deaths (16,000 known dead, 3,000 missing) and 320,000 were made homeless.

The nuclear disaster alone created 100,000 nuclear evacuees.

The lesson, only partially learnt in Japan itself and hardly learnt in other countries, is that natural disasters can come in many unexpected forms and governments must put aside considerable resources and facilities to prepare for and manage them.



The lesson usually becomes obvious when a disaster occurs.

After that, a pledge is made to be better prepared and much of that is not implemented until the next disaster and the cycle begins again.

While the tsunami caused the most immediate damage, it was the nuclear incidents at the Fukushima power plant that were the most shocking and may have the most long-term repercussions.

The nuclear disaster blew away a lot of myths.We now know, again, that nuclear power plants are not safe.

The claim by Tepco – the Japanese company operating the Fukushima plant – that the reactors were fail-safe and could withstand earthquakes, was proven to be wrong.

The ability of the regulatory autho­rities to monitor and check for risks and ensure safety was near absent.
An independent commission, which was set up by the Rebuild Japan Initiative Foundation to investigate the nuclear incident, shows how close Japan came to a catastrophe.

Its chairman Yoichi Funabashi, in an article in last Saturday’s Financial Times, said that Japan was on the edge of an “existential crisis”.

As the tsunami knocked out the Fukushima plant’s cooling systems, the Tepco president indicated his company’s intention to abandon the plant and evacuate its workers.

Japanese Prime Minister Naoto Kan personally intervened, ordering the company not to abandon ship and form a “death squad” to continue the battle and inject water into the reactor vessels.

A worst case scenario, prepared for the prime minister by the Japan Atomic Energy Commission, envisioned a hydrogen explosion, a succession of meltdowns and such extensive radiation that the whole of Tokyo would have to be evacuated.

Funabashi said: “The truth is that the imagined ‘worst-case scenario’ was closer than anyone would wish to admit; but for the direction of the wind (towards the Pacific, not inland, in the four days after the earthquake); but for the manner in which the gate separating the reactor-well and the spent-fuel pool in Unit 4 broke (presumably facilitating the transfusion of water into the pool). Luck was undeniably on our side.”

Funabashi’s commission found that the nuclear industry had become ensnared in its twisted myth of “absolute safety”, propagated by interest groups seeking to gain broad acceptance of nuclear power.

He also found that “Japan’s nuclear safety regulatory regime was phoney. Regulators pretended to regulate; utilities pretended to be regulated. In reality, the latter were far more powerful in expertise and clout”. He offers two lessons to be learnt.

First, is the need to overcome the myth of “absolute safety”, shatter the taboo that surrounds the concept of risks in the nuclear energy business and the need to prepare for the unthinkable and unanticipated.

Second, is the need for an independent regulatory body.

A major fallout from the Fuku­shima accident is the blow it has dealt to the nuclear industry.

It highlighted the danger a country faces when something goes wrong.

Of its 52 nuclear plants, Japan has now shut down 50 plants. The remaining two may also be shut down next month.

Although the government may try to reopen some of them, the public revulsion against nuclear plants could mean that their days are numbered.

There has also been a global backlash, with Germany, Italy, Belgium and Switzerland declaring that they will phase out their nuclear plants.

The situation in Asia, however, is mixed. China has suspended the building of new nuclear plants pending changes in safety standards.
India, Vietnam and Korea are going ahead with their nuclear power programmes.

“If more nuclear power plants are built in developing countries with little experience of operating a reactor, or bordering a region where terrorism is a concern, or without sufficient financial resources to import state of the art technology, then the chance of a major nuclear accident hitting the developing world will loom large in the coming decades,” said Kevin Tu, senior associate at the Carnegie Endowment for International Peace.

Meanwhile The Economist magazine, in its latest cover story, “Nuclear Energy: The dream that failed” is pessimistic about the future of the nuclear industry.

Nuclear plants are costly to build and operate. British studies put the overnight cost of new power plants at US$2,233 (RM6,720) for every kilowatt of capacity in 2004 and US$3,000 (RM9,028)/kw in 2008, according to The Economist.

Capacity fired by gas turbines cost less than one-fifth of that. The cost of renewable energy (wind and solar, in particular) is, however, getting cheaper every year.

Perhaps, the most intractable problem is nuclear waste. As The Economist noted, building a nuclear plant that can last 100 years is one thing, but creating waste that will be dangerous for 100 times as long is another.

So far, countries have failed to create a long-term repository for nuclear waste.

As the public has become intensely more aware of the dangers of radiation, the resistance to locating nuclear plants in their neighbourhood has grown fiercer.

No doubt the Fukushima meltdowns and its aftermath have contributed to increased awareness and to the bad name that nuclear power has acquired.

P/S:  We sympathize with Japan's sufferings from earthquake, tsunami caused by nature that resulted in Fukushima nuclear meltdown a year ago.

How Japan feels when we remember the victims of its Nanjing Massacre committed and occupied by Japanese troops on Dec 13, 1937, China's former capital city suffered a six-week massacre in which more than  300,000 Chinese were Killed, 20,000 Women Raped ... ?


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Thursday, March 17, 2011

Major nuclear accidents around the world, What relationship & causes earthquakes & Tsunamis? Water to cool reactor in Japan!




 Major nuclear accidents around the world





BEIJING - The Fukushima No.1 nuclear power plant in northeast Japan started to leak radioactive material after an hydrogen explosion, which was caused by a devastating earthquake and ensuring tsunamis, occurred Saturday afternoon.


The following are major nuclear accidents around the world since the former Soviet Union set up the world's first nuclear power plant in 1954:


On Oct. 10, 1957, a fire broke out at the Windscale nuclear reactor (later renamed Sellafield) in northwest England, destroying the core and releasing a cloud of radioactive material. The sale of milk and other produces from nearby farms were banned for a month. Scores of people later developed cancer and died because of exposure to radiation.


On March 28, 1979, a partial core meltdown occurred at Three Mile Island in the United States due to its cooling system failure, in the most severe nuclear leak accident in the country which forced the evacuation of at least 150,000 local residents.


On April 26, 1986, the No.4 reactor at the Chernobyl nuclear plant in the former Soviet Union exploded, causing the worst nuclear disaster in history. The explosion killed 30 people on the spot, released more than eight tons of highly radioactive material, contaminated 60,000 square km of land, and caused more than 3.2 million people to be affected by radiation.


On April 6, 1993, a tank containing radioactive liquid exploded at the Tomsk-7 Reprocessing Complex in the Siberian region of Russia. A total of 10 square km of land was contaminated by radioactive material and a number of nearby villages were evacuated.


On Sept. 30, 1999, a nuclear accident occurred at a nuclear fuel plant at Tokai village, Ibaraki prefecture, Japan, killing two workers, exposing dozens of people to radiation and forcing the evacuation of local residents.


On Aug. 9, 2004, four workers were killed and seven others injured by a steam leak at the No.3 reactor at Kansai
Electric's Mihama power plant, 350 km west of Tokyo, Japan.



Relationship between earthquakes, tsunamis

BEIJING - An 8.9-magnitude earthquake struck northeastern Japan on Friday afternoon, the largest temblor ever recorded by the Japanese Meteorological Agency. The earthquake triggered a tsunami that swamped hundreds of kilometers around the epicenter.

The following is a brief introduction of the relationship between earthquakes and tsunamis.

A tsunami is a series of destructive waves, sometimes tens of meters high, caused by the displacement of a large volume of water, usually an ocean. With gigantic energy and fast movement, the waves are catastrophic to the affected coastal areas.

Tsunamis are usually triggered by earthquakes, volcanic eruptions and underwater explosions, landslides and other mass movements. Underseas earthquakes have generated nearly all the major tsunamis in history.

Tsunamis can be generated when the sea floor abruptly deforms and vertically displaces the overlying water. Tectonic earthquakes are a particular kind of temblor associated with the earth's crustal deformation.

When these earthquakes occur beneath the sea, the water above the deformed area is displaced from its equilibrium position.

However, undersea earthquakes do not necessarily lead to tsunamis.

Statistics from the China Earthquake Administration show that of the past 15,000 undersea tectonic earthquakes, only about 100 generated tsunamis. Some experts hold that only earthquakes of above 6.5 magnitude and with a focal depth of less than 25 km underground can cause tsunamis.

Sometimes even strong earthquakes, such as the 8.5-magnitude qukae that occurred near Sumatra in 2005, do not trigger tsunamis because the quake intensity can be largely compromised by the great focal depth, experts say.

In addition to the earthquake magnitude, global climate change may also have a bearing on the occurrence of tsunamis.

According to experts from the China Meteorological Administration, the 2004 tsunami that struck Southeast Asia was partially linked to the rising sea level caused by global climate change.


What causes earthquakes?

The earth has four major layers: the inner core, outer core, mantle and crust.

The crust and the top of the mantle make up a thin skin on the surface of our planet. But this skin is not all in one piece -- it is made up of many pieces like a puzzle covering the surface of the earth.

Not only that, but these puzzle pieces keep slowly moving around, sliding past one another and bumping into each other. We call these puzzle pieces tectonic plates, and the edges of the plates are called the plate boundaries.

The plate boundaries are made up of many faults, and most of the earthquakes around the world occur on these faults. Since the edges of the plates are rough, they get stuck while the rest of the plate keeps moving.

Finally, when the plate has moved far enough, the edges unstick on one of the faults and there is an earthquake.

Helicopters dump water to cool reactor in Japan

TOKYO - Japan's Self-Defense Force are dumping water on the damaged No 3 reactor by helicopter following the plant's operator Tokyo Electric Power Co (TEPCO) failing to cool it sufficiently on Wednesday and Thursday.
Helicopters dump water to cool reactor in Japan
A video grab show a helicopter is dumping water on a stricken reactor in Japan to cool overheated fuel rods inside the core on March 17, 2011. [Photo/Xinhua]  
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The plan was originally shelved as it was deemed too dangerous in light of the high levels of radiation, but following the rising heat of the reactor the government decided the water drop by the helicopters would be the best way to deal with climbing hydrogen levels.

The GSDF Ch-47 helicopters can carry up to 7.5 tons of water and have also started dumping water on the No 4 reactor as well.
Meanwhile, a Tokyo police unit is primed to use a water cannon truck to cool down a spent fuel rod pool in the No 4 reactor at the quake-stricken Fukushima Daiichi nuclear power plant.

The police announced that the ground operation will involve spraying water from outside of the reactor and is due to start on Thursday morning.

Following Friday's devastating earthquake and tsunami in northeastern Japan, the temperature has been rising in the building that housing the No 4 reactor and its spent fuel storage pool, as cooling systems failed.

The building was rocked by a hydrogen explosion on Tuesday as well as a fire early on Wednesday adding to complications and raising concerns the fuel rods will melt and release radiation.

The police will aim their high pressure cannons at a hole in the wall of the damaged No 4 reactor housing structure to target the fuel storage pool.
Helicopters dump water to cool reactor in Japan
A video grab show helicopters are dumping water on a stricken reactor in Japan to cool overheated fuel rods inside the core on March 17, 2011. [Photo/Xinhua] 

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