The Chernobyl Disaster

On the 26th of April in 1986 one of the worst nuclear disasters in history occurred at the Chernobyl nuclear power plant in the Ukraine. The number 4 reactor at the Chernobyl Nuclear power plant ended up exploding after several errors that occurred during a scheduled safety systems test. The explosions released large amounts of radioactive materials into the sky and it was spread over great distances by wind streams. The repercussions of the disaster are only now being better understood today. The reactor type at Chernobyl was a RBMK type reactor. The reactor is a vertically oriented reactor that uses graphite as an insulator which also caused problems due to the combustibility of the graphite that was used. "The reactor fuel is zirconium alloy clad uranium oxide enriched to 2.0% U-235" (Mosey). The RBMK reactor also has two 500MWt reactors which operate safely at 100% power of 1000MWt. "Reactor control is achieved by means of 211 boron carbide absorber rods" (Mosey). The purpose of the rods is to absorb the excess electrons in the core and to control the rate in which the reaction is taking place. At Chernobyl nuclear fusion occurred by bombarding an isotope of Uranium 235 with an electron thus causing it to become unstable and split into other radioactive elements and at the same time releases a great amount of energy that we harness, and several electrons which continue the reaction.
"The test involved using the residual energy of the turbogenerator as it ran down to provide electricity for the main circulating pumps to reduce the time the pumps would be without power following a postulated loss of electrical power" (Mosey). Initially they decreased the power of the reactor to 50% power and isolated the ECI (emergency coolant injection system for a period of 22 hours and during this portion of the test everything checked out alright. After they had completed that portion of the test they decreased the power even farther to about 20-30% of full power. "The

Cited: Baverstock, Keith, and Dillwyn Williams. "The Chernobyl Accident 20 Years On: An Assessment of the Health Consequences and the International Response." Environmental Health Perspectives 114.9 (2006): 1312-317 Mosey, David. Chernobyl, 26 April 1986. 6 April 2006. Nuclear Engineering International. 23 March 2007 http://www.neimagazine.com/story.asp?storyCode=2035370 The Chernobyl Disaster. 27 April 2006. BBC News. 23 March 2007 http://news.bbc.co.uk/2/shared/spl/hi/guides/456900/456957/html/nn1page1.stm