ITM 574: Assignment 4- Chernobyl Nuclear Disaster

The Chernobyl nuclear plant disaster is considered to be the worst ever disaster occurred in the history. The Chernobyl nuclear plant is situated in Pripyat , Ukraine and is the major source of electricity in the country. Around 10% of the nations electricity is produced in that plant. Originally it consisted of 4 reactors build successively in 1977, 1978, 1981 and 1983. Reactors number 5 and 6 were under construction at the time of accident.
On April 26, 1986 at around 1:23:45 a.m. reactor number 4 had a massive catastrophic power excursion, which resulted into a steam explosion. The roof of the reactor nearly tore out emitting nuclear radiations or radioactivity, which affected multiple nations and thousands of people.
The day before the accident, the reactor no. 4 was to undergo an emergency power failure test. A voltage regulator operation was to be tested, which in case of external power failure would provide power to run the water pumps for cooling the reactor.

Planning the test of the safety device

During the daytime of 25 April 1986, reactor 4 ( [show location on an interactive map] 51°23′22″N 30°05′56″E / 51.38944, 30.09889) was scheduled to be shut down for maintenance as it was near the end of its first fuel cycle. An experiment was proposed to test a safety emergency core cooling feature during the shut down procedure.

A very large amount of cooling water is needed to maintain a safe temperature in the reactor core. The reactor consisted of about 1,600 individual fuel channels and each operational channel requires a flow of 28 tonnes of water per hour. There was concern that in case of an external power failure the Chernobyl power station would overload, leading to an automated safety shut down in which case there would be no external power to run the plant's cooling water pumps. Chernobyl's reactors had three backup diesel generators. The generator required 15 seconds to...

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