The Chernobyl Disaster Essay Research Paper The

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The Chernobyl Disaster Essay, Research Paper The Chernobyl disaster on April 26, 1986 is described as one of the most frightening environmental disasters in the world. The plant was made up of four graphite reactors, which were the most modern Soviet reactors of the RBMK-type. Two more of these reactors were still under construction at the station. Chernobyl was an obscure town in north central Ukraine (former Soviet Union) on the Pripyiat River near the Belarus border. Immediately its name was joined to the Nuclear Power Plant located twenty-five kilometers upstream. The plant is actually located fifteen kilometers northwest of the city. It is not only the radioactive mess left that strikes fear. Nineteen similar stations are still running, because neither the former Soviet

Union nor its republics can afford to shut them down. The world first learned of this accident from Sweden, where unusually high radiation levels were noticed at one of their own nuclear facilities. At 1:23 am technicians at the Chernobyl Plant took some erroneous actions that will impact the course of Soviet events without exaggeration. Human error is what basically caused the disaster. These operators of the fourth unit slowly allowed power in the reactor to fall to low levels as part of a controlled experiment gone wrong. The purpose of the test was to observe the dynamics of the RMBK reactor with limited power flow. Twelve hours after power reduction was initiated, power reached 50 percent. Only one turbine was needed to take in the decreased amount of steam, so no. 2 was

turned off. Power was then reduced to 30 percent. One of the operators made a mistake. Instead of keeping power at 30 percent, he forgot to reset a controller, which caused the power to plummet to 1 percent. Now water was filling the core, and xenon (a neutron absorbing gas) built up in the reactor. The power was too low for the test. The water added to the reactor is heated by the nuclear reaction and turned into steam to turn the turbines of the generator. The operator forced the reactor up to 7% power by removing all but 6 of the control rods. This was a violation of procedure and the reactor was never built to operate at such low power. This type of reactor is very unstable when filled with water. The operator was not successful in getting the flow of water corrected and the

reactor was getting increasingly unstable. The operator disabled emergency shutdown procedures because a shutdown would abort the test. By 01:22 AM, when the operators thought they had stable conditions, they decided to start the test. The operator blocked automatic shutdown because of a fear that a shutdown would abort the test and they would have to repeat it. The test began and the remaining turbine was shut down. Power in the reactor began to gradually rise because of the reduction in water flow caused by the turbine shutdown, which lead to an increase in boiling. The operator initiated manual shut down, which lead to a quick power increase due to the control rod design. The reactor reached 120 times its full power. All the radioactive fuel disintegrated, and pressure from

all excess steam broke every one of the pressure tubes and blew the entire top shield of the reactor. All of these factors including serious violations of safety operations, dangerous design flaws, and imperfect control systems is what led to the virtually instantaneous catastrophic increase of thermal power which led to core meltdown. The steam explosion also destroyed part of the building. Radioactive material was then thrown out into the atmosphere for over 10 days. Multiple fires were formed both inside and out of the reactor. By five o’clock the firemen had smothered the flames. In later days, about 5000 tons of materials were thrown into the reactor well from helicopters of the air force to extinguish burning graphite and suppress radiation release. The flow of different