Chernobyl: The Design of Disaster Essay

realize that the plant was having an accident with the coolant level. The tubes holding the nuclear fuel began to melt since they became over heated which also caused fuel pellets to melt. Even though this was the most dangerous kind of nuclear accident, the radiation did not reach outside of the containment building nor did it release out into the environment. There were no immediate injuries or deaths reported from the raditation to the faculty workers.

his led to the melting of the fuel and a drastic increase in radioactivity within the reactor coolant.This also resulted in leaks in the coolant system, which led to small amounts of radiation escaping into the environment.[7]

The disaster had more of an effect on eastern Europe’s nuclear experimentation and use but “While no-one in the West was under any illusion about the safety of early Soviet reactor designs, some lessons learned have also been applicable to Western plants” (World Nuclear Association). Since the Chernobyl disaster was majorly caused by human error and under qualified scientists, to work with nuclear reactors today you need to be insanely qualified. Since the accident, Soviet-designed reactors’ safety has improved greatly, even in smaller ways. Automatic shutdown mechanisms now work faster, and other safety mechanisms have been sped up. Even new equipment has been installed such as automated inspection equipment. Several scientist and reporters have even said an accident like Chernobyl is virtually impossible with today’s technology (World Nuclear Association).

The basic causes of the meltdown were the damages to backup generators on reactors 1 through 3 by the sea water. This forced the emergency lights and cooling system to shutdown (which resulted in an overheating of the reactors). What made the situation worse is that Japanese officials were in a state of panic after the disaster. This is because they did not realize that the cooling systems were shut off and that the problem was compounded from the lack of response. ("Fukushima Utility")

This did not mean that the valve had actually performed that action, but rather that the message was received by the valve (History Channel…). The light shut off, which indicated to the operators that the valve had been opened and reclosed, however the valve did not reclose (Wikipedia). The PORV remained open and was releasing a combination of coolant and radioactive material. As coolant water was released, no instrument indicated this to the operators; the operators had only been trained to estimate the amount of water in the reactor by doing calculations based upon pressure readings. These pressure readings were now skewed and thus the calculations were wrong and based upon these wrong calculations, the operators stopped the flow of cooling water to the reactor. The lack of water caused overheating within the reactor and according to the US Nuclear Regulatory Commission’s findings, about half of the reactor’s core melted. Operators had no way of knowing this and also were not trained to handle such an event. Unlike the event at Chernobyl, the reactor stayed intact and massive amounts of radiation were not leaked into the surrounding area. This containment, led nuclear engineer, Jack Herbein to announce publically that the citizens of Harrisburg were in no danger. Herbein’s comments on the plant were near fraudulent because no one was certain as to the actual danger that they were in

At 1:00 A.M. on 25 April, the command was given to start reducing power to the station. “This could not be done quickly because the xenon gas that came from the radioactive decay of uranium 135 absorbed neutrons. If not allowed to decay, which it did in a few hours, it could accelerate the decline in the reactor’s activity and close it down altogether.” (Read p.59) Twelve hours after the start of the power reduction, the reactor had reached half-power, and generator number 7 was switched off. The number 8 generator would be next, but there was a slight risk that the decrease in water supply to the reactor or the start up of the auxiliary generator would signal an emergency to the system sensors that would automatically start the emergency core cooling system. If this happened, the reactor would be flooded and it would be closed down. Dyatlov had the emergency system disconnected so that the test could continue uninterrupted. After the this system was disconnected, the test was ready to proceed, which was to reduce power in the number 8 generator and take it off line, all the while keeping the reactor on low power. As the order was given, a call came in from the power grid dispatcher in Kiev saying that the power that the number 8 generator produced was needed until 11 P.M., which meant that the test had to be postponed. (Read, 1993)

On March 1979, in Harrisburg, Pennsylvania Three Mile Island there were misread gauges and poor decision that lead to the melting of the core reactor. But after the core melted

The incident was rated a five on the seven – point International Nuclear Event Scale. It’s mean accident with Wider Consequences. The Incident was caused by combination of equipment malfunctions, design – related problems and worker errors led to partial meltdown and very small off – site releases of radioactivity. The reactor was destroyed. The cleanup of the damaged took nearly 12 years and cost almost 1 billion $.

Nevertheless, their attempts to cool the reactor failed due to a malfunctioned cooling system that had a possible blockage in the water supply piping or a valve failure. The temperature and pressure inside the reactor began to rise uncontrollably in a runaway chemical reaction. Inside the reactor the pressure was still, increasing reaching 400 pounds per square inch and boosting the rupture disc. A good example of what was happening is to compare it to a tea kettle on the stove. As steam and heats up within the kettle, it looks for an opening to relieve pressure. When the steam finds that opening it begins to make the whistling sound which gets louder and louder as the water continues to heat up and the steam escapes the kettle more quickly.

Early in the morning of April 27, 1986, the world experienced its largest nuclear disaster ever (Gould 40). While violating safety protocol during a test, Reactor 4 at the Chernobyl power plant was placed in a severely unstable state, and in a matter of seconds the reactor output shot up to 120 times the rated output (Flavin 8). The resulting steam explosion tossed aside the reactor’s 1,000 ton concrete covering and released radioactive particles up to one and a half miles into the sky (Gould 38). The explosion and resulting fires caused 31 immediate deaths and over a thousand injuries, including radiation poisoning (Flavin 5). After the

The main reason that could be attributed to the cause of the Chernobyl accident was due to the irregular condition of the reactor on the day.

The main reason for the mishap is by now well recognized (Petryna 1). However, initially the Chernobyl catastrophe baffled the minds of people in the 20th century and definitely left the people of Ukraine disordered while living in anxiety. Now, without question, the public knows that the accident at Chernobyl was the result of a disastrous combination of ignorance from the Ukrainians and complacency from the Soviets in control of Ukraine at the time. As according to American physicist and Nobel laureate Hans Bethe, “…the Chernobyl disaster tells us about the deficiencies of the Soviet political and administrative system rather than about problems with nuclear power." The immediate basis of the Chernobyl accident was a mismanaged electrical-engineering experiment (Rhodes "Chernobyl", PBS). While, the indirect source of the calamity was an industrial malfunction of a Soviet made nuclear-based machine. Ironically, the Chernobyl accident occurred during a test run, which was conducted to improve plant safety. This accident proved once more what experienced control engineers have all learned: that a process must be understood before it can be controlled. (Liptak “Control Global”). Engineers with no familiarity of reactor physics were interested to see if they could draw electricity from the turbine generator of the Number 4 reactor unit to run water pumps during an emergency, when the turbine was no longer being driven by the reactor but was

The disaster took place on April 1986, and was caused by inexperienced staff. When the power plant had to undergo a special test, to make sure that sufficient amount of cooling water would be supplied to the reactor in case of a power outage. However, the test had been delayed, because the national grid required the power output more than the expected time. Hence, the test was postponed after midnight where the night shift had to come. The night shift had little experience about such a test as most of them were electrical engineers rather than nuclear. On the other hand, the night shift had to perform the test before the grid needed the power again, otherwise they would have all been fined or fired. Consequently, lead to an unnecessary pressure on the personnel, which in turn increased the probability of making incorrect

The causes of the accident was quite complex. In brief, it began with a closed bypass valve, which stopped the water flowing to the secondary main feed water pumps, once the steam generators could not receive water, they stopped and the reactor emergently shutdown. Control rods were inserted into the

Which meant that the reactor’s moderation level, which was controlled by graphite rods that absorbed neutrons, had to account for the neutrons absorbed by light water. In addition, when light water boils, it’s neutron-absorption capacity just about vanishes. So, in n the event of evaporation of water to steam, the place occupied by water would be occupied by water vapor, which has a density vastly lower than that of liquid water. This results in allowing more neutrons to fission more U-235 nuclei and in that way increases the reactor’s power. Hence, higher temperatures is achieved and more water is boiled. As a result of this, the steam in the coolant water would then produce what scientist call a void, a bubble that does not absorb neutrons. While the moderation of neutrons done by the graphite is reduced by light water; neutrons become easily absorbed to continue the reaction. As a consequence, this would severely change the balance of neutron production, causing a situation in which more and more neutrons are produced. Thus, while the safety procedure was being carried out the operators noticed the power surge being created and realized they needed to reduce the reactivity rapidly by introducing in more control rods. But the control rods had a design flaw that would lead to an engineering disaster. The tips of