FREE ESSAY ON CHERNOBYL

CHERNOBYL

: 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 substances continued until the beginning of June 1986. It
is still not clear if the dumping of these materials actually achieved their goal. Recent
data has shown only a small part of the materials actually got into the well.
Due to the accident, the people of Chernobyl were exposed to radioactivity 100 times
greater than the Hiroshima bomb. The people of the world and Northern Europe were greeted
with clouds of radioactive material being blown northward through the sky. Seventy
percent of the radiation is estimated to have fallen on Belarus and 10 years later babies
are sill 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 60 Billion dollars
to make these people healthy. Thirty-one lives were lost immediately, and more than
600,000 people were involved with the cleanup. 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. Huge sums of many have been spent, and will continue to be spent to
relocate settlements and decontaminate the once rich farmlands.
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. Construction of new plants in the
Soviet republics were 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 building works in the world. In charge of building
the tomb was Construction Department No. 605. 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. Other sensors monl
On the whole, there are some different points and aspects from the authors to explain the
effects of immigration on labor market. They are the demand and supply, investment,
expenditure form government, skilled immigrants, mobility and the empirical findings.
Although there are both advantages and disadvantages from immigration, most authors
believed that there is no causal link between immigration and unemployment. However, it
is possible that they emphasized the benefits and gave insufficient attention to the
costs of immigration on the labor market. In my view, government should consider more
aspects from the effect of immigration on labor market for making the policy well. Also,
government should not put most responsibilities of unemployment on immigration in order
to escape the blame from high unemployment because it is not fair to the contribution
from immigration and make an unreal image of immigration to society.