Title: Chernobyl Disaster
Names: Lauren and Mary
Teacher: Mr. Schmit
Standards: 901,904,905

external image bp2.jpg

Chernobyl: The World’s Worst Nuclear Disaster
By: Mary and Lauren
Published: May 15, 2011

The morning of April 25, 1986, seemed like a routine day for workers at the Chernobyl power plant. They had started to conduct a routine test to determine how long turbines would spin and supply power to the main circulating pumps. Previously, there had been a loss of main electrical power supply, so new voltage regulator designs were being tested. No one could have predicted that within a few hours, the world’s worst nuclear disaster to date would devastate the environment of a small, rural town in a country once called the Soviet Union.

The problem ultimately occurred on the morning of April 26, 1986. Although the government tried to deny the incident at first, the nuclear meltdown of Reactor Number 4 at the Chernobyl power plant near the town of Pripyat, in Ukraine, which was then part of the Soviet Union, was ultimately going to affect history.

Human error was a great factor in how the disaster played out. Due to operator error at the plant during the routine test, this was considered the root cause of what became a chain of events that contributed to the overall disaster. The safety systems were switched off and the test was being conducted under improper and unstable conditions, which led to a power surge. Although the operator moved to shut down the reactor, it had already proved too late. The reactor was already experiencing a power surge because of the peculiar design of the control rods while being inserted into the reactor. This power surge caused the nuclear fuel to overheat and resulted in a series of steam explosions which severely damaged the reactor building and destroyed the Unit 4 Reactor.

The technological design of the plant also contributed to the disaster. The type of plant that the Soviets designed for Chernobyl was called the RBMK which stands for the Russian acronym - 'reactor cooled by water and moderated by graphite'. The RBMK reactor also used nuclear fission to split nuclei and therefore create energy. The intense pressure caused the cover plate of the reactor to partially detach, causing the fuel channels to rupture and jam all the control rods. Steam was heavily generated, causing a steam explosion which released fission products into the atmosphere. A second explosion occurred two to three seconds later. This second explosion released fragments from the fuel channels and the plant's moderator (hot graphite). Both explosions contributed to the largest uncontrolled radioactive release in history.

The radioactive smoke drifted over sections of the western part of the Soviet Union and much of Europe. Only after alarms went off at a nuclear power plant in Sweden the next day did the Soviets admit to the disaster.

This reluctance to admit their error led to many negative effects to the people living in surrounding areas that could have been prevented. Authorities in the nearby town of Pripyat waited 36 hours to evacuate residents, exposing residents to radioactive fallout for a day and a half.

The effects of radiation and the severity of the contamination have been points of contention with experts around the globe. Because of the lack of reliable public health information before 1986, it is difficult for experts to determine the exact figures of radiological poisoning. But because of Chernobyl, international organizations and panels have been created to address the regulation of nuclear energy and to prevent further disasters.

For example, the government of the Soviet Union decided to coordinate an international experts’ assessment of the disasters’ environmental, radiological, and health consequences in several nearby towns following the incident. Encouraging future discussion and opening channels of communication to remove the stigma behind such a tragic disaster will only help to broaden the world’s knowledge of nuclear disasters and how to react in the future.

In 1989, the World Association of Nuclear Operators was formed in order to create links between the East and West regarding the safety and operation of various plants. This important contribution to the scientific and international community has helped minimize reactor deficiencies.

Chernobyl has also shed further light on the effects of radioactive poisoning on the lives of individuals. In total, more than 350,000 people had to find new places to live following the accident. Although the total number of fatalities directly linked tot the accident stands at 30 (two Chernobyl plant workers died on the night of the accident while 28 more died within a few weeks because of acute radiation poisoning), the lasting effects of radioactive fallout have contributed to around 600,000 people being classified as “significantly exposed”, where their health will need to be monitored for the rest of their lives. These numbers vary as experts argue as to how to differentiate between normal biological factors and the effects of radiation.

Technological modifications have also been made to RBMK reactors still operating in order to prevent another disaster like Chernobyl. Originally, the nuclear chain reaction and power output could increase if cooling water was lost or turned to steam. Now, all of the RBMK reactors' control rods have been modified. Neutron absorbers have been added and this has increased the fuel enrichment of these reactors, allowing them to be more stable at low power. Because of more technological advances, automatic shut-down systems operate faster and other safety systems have been improved. Automated inspection equipment has also been installed. Although the world will continue to face a risk when utilizing nuclear energy, there is confidence that a disaster as bad as Chernobyl will never occur again.

Chernobyl Slideshow

Chernobyl Slide Show

Works Cited

Badkar, Mamta. "Look What Uncontained Nuclear Meltdown Did to Chernobyl." Business Insider. 15 Mar. 2011. Web. 14 May 2011.
"Scientific Facts on the Chernobyl Nuclear Accident." Green Facts. 5 Mar. 2011. Web. 14 May 2011.

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