Level 16 - Colossus
The Chernobyl Accident
“No center of population on the earth’s surface is secure from surprise destruction in a single attack. There is no defense in science against the weapon which can destroy civilization.” (Gale 210) 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. (Medvedev 4) 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 Pripyat River near the Belarus border. (Gale 135) Immediately its name was joined to the Nuclear Power Plant located twenty-five kilometers upstream. It is not only the radioactive mess left that strikes fear, but 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 would impact the course of Soviet events without exaggeration. (Gale 27) In my paper I will discuss the causes and effects of the Chernobyl accident.
Human error is what basically caused the disaster. (Medvedev 1) 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. (Medvedev 36-39) 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. Leonid Toptonov, a young, inexperienced and tired operator allowed the level of reactivity to fall dangerously low. As he attempted to correct this, the power in the reactor rose dramatically and uncontrollably. 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. Leonid forced the reactor up to 7% power by removing all but 6 of the control rods. (Medvedev 26-36) 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. (Medvedev 37) 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 1:22 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 led to an increase in boiling. The operator initiated manual shut down, which led 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. (Medvedev 26-36)
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 substances continued until the beginning of June 1986. Recent data has shown only a small part of the materials actually got into the well, therefore this was not as effective as it was suppose to be. (Medvedev 26-39)
The Soviets tried to cover the whole situation up. Finally, at 9 p.m. on Monday, a newscaster on Moscow television read a statement from the Council of Ministers that seemed to raise as many questions as it answered. The announcer stated that there had been an accident at Chernobyl Nuclear Power plant and measures were being taken to eliminate the consequences of the accident. (Time 39) Thus began by far the gravest crisis in the troubled 32-year history of commercial atomic power. The fallout caused an international uproar against the Soviet Union for its lax safety measures and its concealment of the fact that the dangerous radiation was floating toward neighboring countries. (Time 39)
The Chernobyl accident's consequences, aggravated by the political, economic and social changes of the past years, have led to a worsening in people's quality of life and health, and to negative impacts on social activity. The situation has been further complicated by the spreading of incomplete and distorted information on the accident consequences and measures for their alleviation (during the first years). (Reactions 1-4)
Due to the accident, the people of Chernobyl were exposed to radioactivity 100 times greater than that of the Hiroshima bomb. (Cochems 2) The people of the world and Northern Europe were exposed to clouds of radioactive material being blown northward through the sky. Seventy percent of the radiation is estimated to have fallen on Belarus. (Ten years later babies were still being born with no arms, no eyes, or only stumps for limbs. No one can predict the exact number of human victims. It is estimated that over 15 million people have been victimized by the disaster in some way. It has also estimated that ultimately the accident will claim more victims than World War II. It will cost over 20 Billion dollars to make these people healthy. (Medvedev 1) Thirty-one lives were lost immediately, and more than 800,000 people were involved with the cleanup. (Cochems 2) Many are now dead or sick. Hundreds of thousands had to abandon entire cities and settlements within the thirty-kilometer zone of highest contamination. Possibly as many as three million still live in contaminated areas. Ten thousand of these are still living in the city of Chernobyl today.
The Environmental and Agricultural Impacts were also quite significant. Huge sums of money have been spent, and will continue to be spent to relocate settlements and decontaminate the once rich farmlands. Nearly 3 million acres of agricultural land is lost for decades because of contamination. At first the soil around Chernobyl was severely polluted and therefore no one would purchase agriculture from that region. Eventually as time passed and pollutants eroded, the selling of agriculture rose again, but not to what it was before. The contamination of milk and meat were both serious problems. After years of letting the radioactive materials decontaminate the levels of radioactivity became closer to normal. The Soviets still faced discrimination in the trading market, because of their radioactive meat and milk, which by this time was normal. (Medvedev 105-111)
Chernobyl has developed as an icon for the terror of uncontrolled nuclear power and abilities, and for Soviet deception and inability to provide safe conditions for workers and basic services such as transportation and health care, especially in times of greatest need. The catastrophe also halted a highly potential nuclear program. The impact of the Chernobyl Accident on a Nuclear Energy Policy is tremendous. Some countries stopped national nuclear energy programs. (Medvedev 290-307) Construction of new plants in the Soviet republics was frozen. Public opinion was directed against nuclear power plants. Some plants were even shut down, but have now been reactivated. The accident has also initiated an international activity in the area of nuclear safety and nuclear emergency planning. Many countries started a development of decision support systems for nuclear accident cases.
The way in which Soviet leaders have dealt with the situation is very unsettling. In the aftermath of the catastrophe several designs to encase the damaged reactor were reviewed. The option that was selected included the construction of a massive structure in concrete and steel that used what remained of the reactor walls as support. Its construction is considered one of the most complicated buildings works in the world. In charge of building the tomb was Construction Department No. 605. (Groiler 1) They ran into many problems while constructing the massive concrete and steel shell. Concrete blocks for the tomb were pieced together far from the reactor itself, and the roads entering the facilities were not accommodated for such loads, which made it difficult for the drivers. Once the blocks were delivered, the workers needed to put them in place. Each weighed several dozen tons so eventually crane operators had to perform this task. This outer protective wall, 28 stories high, is placed around the perimeter and other walls connected to the Unit 3 reactor. A steel roof then completed the structure. The destroyed reactor was entombed in a 300,000-ton concrete structure known as the "shelter" or "envelope." In conditions of high radioactivity the mammoth task was completed in seven months, in November 1986. The site around the plant had then been announced safe for about the next thirty years. However today the sarcophagus is cracked and crumbling. Some of these cracks are as large as a garage door. Multiple sensors were placed to monitor levels of gamma radiation, neutron flux, temperature, heat flux, as well as the concentrations of hydrogen, carbon monoxide and water vapor in the air. (Medvedev 179)
In conclusion, the Chernobyl accident took authorities by surprise by creating so many negative health effects for the world. The accident was basically caused by human error. Its effects were tremendous: killing 31, and exposing over 600,000 to severe radiation. (Medvedev 129) It had huge effects on both agriculture and the environment. At first the Soviets kept the Chernobyl incident a secret, which was the wrong move. If they had informed the rest of the world about the accident sooner, more might have been done to prevent such devastation.