Unformatted text preview: The Chernobyl Accident
MIME 221 Professional Practice Fall 2005 Chernobyl April 1986 1 April 25-26th 1986
1:23 am Reactor #4 becomes critical causing an explosion and massive radioactive debris release. 30 people killed instantly 116 000 people evacuated 2500 death attributed to Chernobyl up to this day 210 000 people resettled 1990-1995 2 Causes Lack of Safety Procedures Design fault in RBMK reactor Violation of operating procedures Communications breakdown Sequence of Events
April 25th, 1986 Reactor #4 scheduled for maintenance shutdown Test to be carried out to determine if enough electricity could be produced during a reactor shutdown until backup generators kick in. Test planned at 1000 MW power level To avoid influencing results, emergency cooling system is put off line (in violation of safety protocols) 3 Sequence of events
Due to time delays and operator errors power level falls to 30 MW Operators remove manually all rods but 8 (safety protocols: never less than 26 rods at all times) Power climbs back to 200 MW, problems with steam pressure to generators. To maintain steam pressure operators reduce feed water flow Sequence of events
Excess steam is produced in the circulation system and reactor gets into the positive void coefficient condition (design weakness) Temperature in reactor core increases rapidly to 100 times the nominal level Reactor #4 becomes critical: confining concrete chamber insufficient to contain explosion: radioactive material is released in the atmosphere. 4 Aftermath
Soviet economy: 12.8 Billion$ loss Contamination: covering a wide area People affected through food chain even outside of the contaminated zone Cancer, birth defects Long term effects on people health Population traumatized But still, Chernobyl nuclear plant remained in operation for 15 years after the accident More on Chernobyl
www.chernobyl.co.uk 5 ...
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This note was uploaded on 03/03/2010 for the course MIME 221 taught by Professor Hassani during the Spring '10 term at MO Southern.
- Spring '10