The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986 at the No. 4 reactor in the Chernobyl Nuclear Power Plant, near the city of Pripyat ...
The problems at the Chernobyl power plant were with reactor No. 4. Specific attributes of this reactor were that it was a light-water-cooled graphite-moderated reactor. This type of reactor has been criticised for its lack of containment structure, and large quantities of combustible graphite within its core. The accident actually occurred during a test run. The idea was to see if the turbines could produce the energy needed during a power cut, to keep coolant pumps working. Safety systems were turned off so as not to affect the test, and the reactor was reduced to 25% power capacity.
Due to a fault the power level plummeted to below 1%, so technicians began to raise the power level slowly. But a power surge occurred and the emergency shutdown, which is designed to halt the chain reactions, failed. The rising power level and temperature got out of control, causing an explosion. This blew off a 1000 tonne sealing cap, causing the radioactive fission products to be thrown up into the atmosphere. The fuel rods melted and graphite moderator set fire.
The mistake blamed for this disaster is that control rods were raised then immediately reinserted into the bundles. The inserting of control rods usually reduces the rate of the chain reaction. But in the case too many control rods were raised and replaced. This then had the reverse effect of raising power levels so fast that it caused the destruction of the reactor.
Lessons learned from disasters
In 2000, Germany decided to phase out nuclear power, and look into sources of power with less severe possible consequences on the environment. The disaster created international debate over the economics and controllability of nuclear power. In most European countries, no new research is being carried out on continuing to build nuclear power plants. Instead the research is aimed at improving safety features at existing nuclear power plants and disposal of nuclear waste. As of 1995, conversely, Asia and Eastern Europe have over 100 reactor units either planned or being constructed.
The number of nuclear power plant inspectors rose vastly after this disaster, and general safety awareness has greatly improved. New regulations on emergency procedures where also put in place.
The effects of the radiation are still affecting inhabitants of nearby countries, and are causing severe health problems amongst the young and old. At least now safety and disaster management are main issues within this industry, and hopefully this kind of event will not be allowed to happen in the future.
Chernobyl's health effects to the general population are uncertain. An excess of 15 childhood thyroid cancer deaths were documented as of 2011.[13][14] A United Nations committee found that to date fewer than 100 deaths have resulted from the fallout.[15] Determining the total eventual number of exposure related deaths is uncertain based on the linear no-threshold model, a contested statistical model.[16][17] Model predictions of the eventual total death toll in the coming decades vary. The most robust studies predict 4,000 fatalities when solely assessing the three most contaminated former Soviet states, to about 9,000 to 16,000 fatalities when assessing the whole of Europe.
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