-
When it was built
They started building in 1968 it was finished in 1978 -
Reactor Failure
The accident to unit 2 started on 4 AM on March 28, 1979. A minor malfunction in the secondary cooling circuit caused the temperature in the primary coolant to rise, a re-leaf valve had failed to closemso much of the primary coolant had drained away. The reactor core suffered saver damage as a result. -
Valve Problems
The pilot operator re leaf valve on the reactor cooling system was open. After about 10 seconds the valve should of closed, but it remained open leaking vital reactor coolant to the reactor coolant drain tank. A valve close signal was sent to the valve but the valve did not actually close, -
Water replacement
Responding to the loss of coolant high pressure injection pumps automatically pushed replacement coolant into the reactor system. As coolant and steam escaped through the re leaf valve coolant surged into the pressurizer raising the water level in it. Steam then formed in the reactor primary cooling system pumping mixture of steam and water caused the reactor pumps to vibrate because severe vibrations could of damaged pumps operators shut the pumps down. -
Coolant restored
Radio active gases release into the air. By late afternoon operators began high injections of water into the reactor cooling system to increase pressure to collapse steam bubbles. By 7:50 they restored forced cooling of the reactor core, which means they where able to restart a reactor pump. -
The release of radio active gas
Radio active gases from the reactor cooling system built up in the make up tank in the auxiliary building. Operators used a system of pipes and compressors to move gas to waste gas decay tanks. The compressors leaked witch caused radio active gasses to be released into the environment. -
Hydrogen bubble
The reactor core was uncovered witch caused a high temperature chemical reaction between water and metal tubes. A sudden rise in reactor building pressure indicted a hydrogen burned had occurred hydrogen gas also gathered at the top of the reactor vessel. -
Release of hydrogen bubble
From march 30th through April 1st operators removed the hydrogen bubble by periodically opening the vent valve on the reactor cooling system for a time officials believed the hydrogen bubble could explode. -
The Shut Down
On April 27th operators established natural convection circulations coolant the reactor core was being cooled by the natural movement of water rather by mechanical pumping the plant was considered to in cold shut down. -
The clean up
The clean up of the damaged nuclear reactor system took nearly 12 years and cost the U.S. approximately 973,000,000 the clean up was unicycle challenging technically and radio logically the plant surfaces had to be decontaminated. About 100 tons of damaged uranium fuel had to be removed form the reactor vesicle all without hazard to clean up workers or to the public.