At low power levels a positive void coefficient meant a decrease in water flow increased steam production and led to an increased neutron flux.  
At low power levels a positive void coefficient meant a decrease in water flow increased steam production and led to an increased neutron flux.  During a test to show a coasting turbine could provide sufficient power to pump coolant, these conditions were reached leading to two explosions. For 10 points, name the site of this April 26, 1986 accident, called the worst man-made disaster in history.
At low power levels a positive void coefficient meant a decrease in water flow increased steam production and led to an increased neutron flux.  
Chernobyl (accept RBMK reactor during first sentence with an amazed look)