Radiation

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HenryJ
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Radiation

Post by HenryJ »

This a good site to grasp the effects of radiation: Chernobyl - Ghost Town - Introduction
Elena wrote:To begin our journey, we must learn a little something about radiation. It is really very simple, and the device we use for measuring radiation levels is called a geiger counter . If you flick it on in Kiev, it will measure about 12-16 microroentgen per hour. In a typical city of Russia and America, it will read 10-12 microroentgen per hour. In the center of many European cities are 20 microR per hour, the radioactivity of the stone. 1,000 microroentgens equal one milliroentgen and 1,000 milliroentgens equal 1 roentgen. So one roentgen is 100,000 times the average radiation of a typical city. A dose of 500 roentgens within 5 hours is fatal to humans. Interestingly, it takes about 2 1/2 times that dosage to kill a chicken and over 100 times that to kill a cockroach. This sort of radiation level can not be found in Chernobyl now. In the first days after explosion, some places around the reactor were emitting 3,000-30,000 roentgens per hour. The firemen who were sent to put out the reactor fire were fried on the spot by gamma radiation.
Elena wrote: On the Friday evening of April 25, 1986, the reactor crew at Chernobyl-4, prepared to run a test the next day to see how long the turbines would keep spinning and producing power if the electrical power supply went off line. This was a dangerous test, but it had been done before. As a part of the preparation, they disabled some critical control systems - including the automatic shutdown safety mechanisms.

Shortly after 1:00 AM on April 26, the flow of coolant water dropped and the power began to increase.

At 1:23 AM, the operator moved to shut down the reactor in its low power mode and a domino effect of previous errors caused an sharp power surge, triggering a tremendous steam explosion which blew the 1000 ton cap on the nuclear containment vessel to smithereens.

Some of the 211 control rods melted and then a second explosion, whose cause is still the subject of disagreement among experts, threw out fragments of the burning radioactive fuel core and allowed air to rush in - igniting several tons of graphite insulating blocks.

Once graphite starts to burn, its almost impossible to extinguish. It took 9 days and 5000 tons of sand, boron, dolomite, clay and lead dropped from helicopters to put it out. The radiation was so intense that many of those brave pilots died.

It was this graphite fire that released most of the radiation into the atmosphere and troubling spikes in atmospheric radiation were measured as far away as Sweden - thousands of miles away.

The causes of the accident are described as a fateful combination of human error and imperfect technology.

In keeping with a long tradition of Soviet justice, they imprisoned all the people who worked on that shift - regardless of their guilt. The man who tried to stop the chain reaction in a last desperate attempt to avoid the meltdown was sentenced to 14 years in prison. He died 3 weeks later.

Radiation will stay in the Chernobyl area for the next 48.000 years, but humans may begin repopulating the area in about 600 years - give or take three centuries. The experts predict that, by then, the most dangerous elements will have disappeared - or been sufficiently diluted into the rest of the world's air, soil and water. If our government can somehow find the money and political will power to finance the necessary scientific research, perhaps a way will be discovered to neutralize or clean up the contamination sooner. Otherwise, our distant ancestors will have to wait untill the radiation diminishes to a tolerable level. If we use the lowest scientific estimate, that will be 300 years from now......some scientists say it may be as long as 900 years.

I think it will be 300, but people often accuse me of being an optimist.

This is some of the newer stuff - Belorussia - Land of the Wolves
Elena wrote: It is time to learn a couple of simple things about radiation types.

Ones that goes through us is called gamma radiation, it is cumulative, it adds up, so we can calculate what a damage it make for health. Gamma is almost identical X-rays. X-rays are human made, while gamma occurs in nature. It is also called a cosmic radiation. Everyone who flying high on plane exposed to the 25 mR/hr of cosmic radiation. Gamma is the toughest type of radiation for immediate problems. It is sort of invisible bullets that can kill in hours, alpha and beta on the other hand are alike to delayed-action mine. With breathing of radiactive dust, they getting inside of a human body, lodges there and in a few years expload with the cancer cells. A beta particle has more mass and less energy then gamma, so it doesn't penetrate matter as deeply. Alpha radiation generally can not travel 4-12cms (1-3 inches) before it stoped, so we can play billiard with balls of a pure plutonium. The dead cells on our skin will stop beta radiation, so even juggling with plutonium balls will be safe, just don't swollow them by mistake.

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