Chernobyl Nuclear Disaster

Chernobyl Nuclear Disaster, (Reuters) – Japan should not expect a repeat of the Chernobyl nuclear disaster after an explosion blew the roof of one of its nuclear plants that had been shaken in a massive earthquake, according to experts on Saturday.

Northern Japan Daiichi reactor 1 of the capital Tokyo began leaking radiation after the 8.9 magnitude earthquake triggered a tsunami and quickly sparked fears of a nuclear disaster.
But experts say the images of mist over the plant suggested that small amounts of radiation were expelled as part of measures to ensure its stability, away from radioactive clouds from Chernobyl who vomits when he exploded in 1986.

“The explosion at the No. 1 generator of nuclear power plant in Fukushima, Japan, which took place today, will not be a repeat of the Chernobyl nuclear disaster,” said Valeriy Hlyhalo, deputy director of the center Chernobyl nuclear safety.

The nuclear emergency in Japan following the massive earthquake disaster recalled 25 years ago at the Chernobyl nuclear power plant in Ukraine, so far the worst nuclear accident in the history of plants.

In the early morning of April 26, a combination of technical and human errors at Chernobyl led to a series of explosions followed by fire and meltdown, releasing huge quantities of deadly radioactive materials in the atmosphere.

The accident occurred during a test of the cooling system of pressurized water plant building Soviet, with unpredictable factors that contribute to a chain reaction of events, beginning with a sudden surge in reactor number four.

Engineers tried to stop the power surge with an emergency stop, but in doing so helped contribute to a further increase in reactor temperature and a number of explosions and fire.

Contrary to the Western nuclear plants, Chernobyl did not containment around the reactor drive, so that in a fire that followed the fallout has been sent into the atmosphere.

Southeast winds carried most of the radioactive particles in neighboring Belarus, but in the weeks that followed, radioactive emissions were also conducted in the East, Western and Northern Europe.

The area around the factory was evacuated in the middle of radioactive contamination and a region of 30 km around the station remains closed to this day. Over 2 million people were evacuated from the area, some, 000 of them permanently.

Once the Soviet government realized the magnitude of the disaster and saw that the envelope open reactor continued to emit radioactive particles into the environment, it has sent soldiers and emergency workers to build common containment around the reactor break provision.

About 1 million workers and 500,000 soldiers were involved in the construction of containment. Although they were sent for only a few minutes at a time, workers were subjected to massive doses of radioactive contamination. Many fell sick and died in subsequent years.

Estimates of the number of victims of the Chernobyl disaster vary. By official accounts, there were direct deaths among the reactor staff and emergency workers.

But the World Health Organization two decades after the accident estimated the death toll at, 000 to, 000. Opponents of nuclear power claim the real figure is over 100,000.

Source: www.usspost.com

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Three Mile Island

Is Japan On the 'Path Of Core-Melt' Nuclear Accident. The cooling system of the Fukushima nuclear power plant in Japan was knocked by Friday's massive earthquack. The temprature of the core has raised to an alarming level.

The Japanese situation appears to be roughly same to the Three Mile Island incident in the United States, where authorities struggled for days to contain an improperly cooled reactor core but were able to avert a widespread release of nuclear material.

Japan announced that there is a small radiations leak from the effected nuclear reactor but thousand of the people living around had been avacuated.

Pressure building in the plant was set to be released soon, a move that could result in a radiation leak, officials said. Some 3,000 people who live within a 3 miles radius of the plant had been evacuated, Kyodo news agency said.

Pressure had risen to 1.5 times the designed capacity, the Japan Nuclear Safety agency said. Media also said the radiation level was rising in the turbine building .

The cooling problems at the Japan ese plant raised fears of a repeat of 1979’s Three Mile Island accident, the most serious in the history of the U.S. nuclear power industry. Experts, however, said the situation was, so far, less serious.

Underscoring grave concerns about the Fukushima plant some 240 km (150 miles) north of Tokyo, The U.S. air force had delivered coolant to avert a rise in the temperature of the facility’s nuclear rods U.S. Secretary of State Hillary Clinton said.

The Japanese public is generally very alarmed about things like radioactive emissions.They have an extreme high standard of safety protection, and they don’t like to see risks like this taken even if the risk is small.

“It’s a very, very risk-averse culture in this regard. So if the authorities are willing to avacuate the people , that might be a sign of how serious they perceive the threat to the reactor.”

 What was the"Three Mile Island Accident:

Three Mile Island accident was a partial core meltdown in Unit 2 (a pressurized water reactor manufactured by Babcock & Wilcox) of the Three Mile Island Nuclear Generating Station in Dauphin County, Pennsylvania near Harrisburg in 1979. The plant was owned and operated by General Public Utilities and the Metropolitan Edison Co. The Three Mile Island accident began about 4:00 a.m. on March 28, 1979, when the plant experienced a failure in the secondary, non nuclear section of the plant.

The main feedwater pumps stopped running, caused by either a mechanical or electrical failure, which prevented the steam generators from removing heat. First the turbine, then the reactor automatically shut down. Immediately, the pressure in the primary system (the nuclear portion of the plant) began to increase. In order to prevent that pressure from becoming excessive, the pilot-operated relief valve (a valve located at the top of the pressurizer) opened. The valve should have closed when the pressure decreased by a certain amount, but it did not. Signals available to the operator failed to show that the valve was still open. As a result, cooling water poured out of the stuck-open valve and caused the core of the reactor to overheat.

The Three Mile Island accident was the most serious in U.S. commercial nuclear power plant operating history, even though it led to no deaths or injuries to plant workers or members of the nearby community. But it brought about sweeping changes involving emergency response planning, reactor operator training, human factors engineering, radiation protection, and many other areas of nuclear power plant operations. It also caused the U.S. Nuclear Regulatory Commission to tighten and heighten its regulatory oversight. Resultant changes in the nuclear power industry and at the NRC had the effect of enhancing safety.

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