What happen in Chernobyl?

On April 26, 1986 nuclear engineer Cliff Robinson's radiation detector went off as he tried to enter his office at the Chernobyl Nuclear Power Plant. He checked the radiation levels of a shoe and could not believe his eyes. Readings had soared and there were signs of radioactive substances never seen before. "My first thought was that a war had broken out and that somebody had blown up a nuclear bomb".

The reactor had an imperfection of control and protection system that made the reactor very unstable. In addition, safety operation rules were violated when the reactor protection system was switched off. This allowed for the disaster to be much more destructive. The second electroturbogenerator was then turned off. This led to a practically instantaneous catastrophic increase of thermal power. As a result, a steam explosion occurred; the reactor and a part of the building were destroyed. Radioactive materials accumulated in the reactor core started to be thrown out into the environment. Multiple fire sites formed both inside the reactor hall and on roofs of nearby buildings because of the explosion. Fire officials smothered main fire sites, except the central reactor hall where graphite continued to burn in the close vicinity of the destroyed reactor. In subsequent days, about 5000 tons of materials, including about 40 tons of substances containing boron and absorbing neutrons, 2400 tons of lead, 1800 tons of sand and clay, 600 tons of dolomite, trinatriumphosphate and polymerizing liquids were thrown into the reactor well from helicopters of air forces to extinguish burning graphite and suppress radioactive release.

By 5 o'clock on April 26, 1986 the fire officials smothered main fire sites except the central reactor hall, where graphite continued to burn in the close vicinity of the destroyed reactor. Contrary to existing reports new reports concluded that the helicopter airlifts of 5,000 tons of clay and other materials to smother the smoldering reactor core was unsuccessful. The pilots of the over 1,800 helicopter missions were told to aim for a "red glow" in the reactor building, which Soviet officials believed to be the burning core. According to the reports, the pilots hit the wrong target. The reports indicated that the core was actually located about 50 feet from the glow. The source of the glow remains uncertain. However, it could have been a small chunk of burning reactor material ejected during the initial explosion. Because the core was never smothered, the reactor continued to burn for 10 days before it was finally extinguished. The core underwent what experts consider the worst-case scenario a complete - core meltdown. Nine days after the accident, the liquefied core melted through the 6-foot radiation shield of the reactor chamber and spilled out into the concrete floors of the level beneath. There the material spread out enough to end the nuclear reaction.

The reactor emitted between 185 and 250 million curies of radiation because the core was not shielded immediately. These levels are three to five times as high as the 50 million curies reported in the official Russian account. In comparison, one curie is the amount of radiation given off by one gram of radium. In addition, the large amount of radiation seems to be linked to a higher incidence of thyroid cancer among children in Ukraine and nearby Belarus. One of the most pervasive myths about Chernobyl is that only 3% of the reactor core were released into the biosphere when the explosion occurred on April 26, 1986. Vladimir Chernousenko, Scientific Director of the Ukrainian Academy of Sciences' Task Force for the Rectification of the Consequences of the Accident, in his 1991 book Chernobyl, Insight From the Inside, dispels this myth (and a partial list of 20 others), citing a more official view on `The Nuclear Accident in Block 4 of the Chernobyl Nuclear Power Station and the Safety of the RBMK Reactor' gives the following excerpts from an unpublished report by A.A. Yadrikhinskii, Nuclear Safety Inspection Engineer of the USSR State Atomic Energy Survey Commission (Kurchatov town, RSFSR February, 1988):

"Radiation emission was no less that 80% of the core (with a total of 192 tons), which amounted to 6.4 x 10^9 Ci. Choosing to ignore the facts about how we are collectively contaminating this Earth with lethal-to-all-life-doses of man-made nuclear fission products will ensure the cessation of billions of years of life exploring itself on this planet. It doesn't have to go down this way. If we were living in the areas that the children described below are, we would not be able to ignore the facts which the International Nuclear Mafia continuously deny when they parrot the line in the global media about how "There's no health danger from nuclear power" and "No one died at Chernobyl" and "This form of energy is clean and safe; anyone who says otherwise doesn't know what they're talking about".

The incident took a brutal toll on the community. Thirty people (staff of block and fire brigade) died receiving high doses of radiation. The contaminated area has been measured to be more than 130,000 sq. km. Approximately 4.9 millions people lived on this territory before the accident. All population from 30-km zone was evacuated. A number of people were relocated. Impact of the Chernobyl Accident on the Nuclear Energy Policy is tremendous. Some countries stopped national nuclear energy programs all together. Constructions of new plants in USSR were frozen. Globally, public opinion was directed against nuclear power plants. Some plants were closed. The Chernobyl accident had initiated an international activity in the area of nuclear safety and nuclear emergency planning.