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“Windscale” Site Construction Begins
- Site of former WWII ordinance factory
- Reactors built for plutonium production
- 2 reactors to be built - Pile 1 and Pile 2
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Warned About Wigner Energy Buildup
- Edward Teller visited site and warned that design might lead to a fuel rod fire
- Wigner Energy = Potential energy created by Neutrons knocking atoms out of place in lattice structure of material
- Wigner Energy has potential for huge energy release (massive heat)
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Pile 1 (Reactor) Operational
- Gas Cooled, Graphite Moderated Low Temperature Reactor
- Began generating weapons grade plutonium
- Operated at a lower efficiency (30% of spec) due to graphite quality used
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Pile 2 (Reactor) Operational
- Reactor more efficient (90% of specs)due to higher quality graphite use
- Reactors began producing 198 pounds of plutonium annually.
- Air filters installed at top of pile chimneys called “Cockcroft’s Follies”
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Pile 2 Spontaneous Heating Event
- Pile 2 experienced a temperature spike while being shut down.
- Blowers started and core cooled to normal temperatures
- Design flaw in uranium cartridge ejection discovered.
- Cartridges occasionally miss the water cool down tank or fall into the reactor
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Pile 1 Spontaneous Heating Event
- Pile 1 experiences heating event while shutdown
- Smoke observed coming from the core suggesting graphite fuel elements burning/smouldering
- Regular annealling procedures implemented to try and counteract and relieve Wigner Effect
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The Burning Deep Within
- Graphite temps began rising on Oct 9
- Oct 10 temps reached 820 degrees F
- Blue flames observed in back of reactor indicating graphite was burning (Wigner Energy)
- Radiation Levels Detected in Chimney, levels continued to rise over time.
- Air used for cooling fed fire increasing temps and radiation levels as uranium began catching fire.
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Drown It or Blow Everyone Away
- CO2 used to suppress flames to no effect
- Decision to flood reactor with water made, despite great risk of a massive hydrogen explosion being triggered.
- 11 tons of uranium on fire releasing radionuclides into atmosphere
- Temps recorded at 2372 degrees Fahrenheit.
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Fury Recedes
- At 10:10 AM on Oct 12 the fans were shut down, this combined with the water finally terminated the fire and the reactor began to cool.
- Incident rated 5/7 on the International Nuclear Incident Scale
- No other air cooled reactors have been built since
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Not The Milk!
- Estimated to be released into the air during fire:
- 600 terabecquerels of iodine-131, 100 fatal and 90 non-fatal thyroid cancers
- 4.6 terabecquerels of cesium-137
- 8.8 terabecquerels of polonium-210, 70 fatal and 10 non-fatal lung cancers
- Give half-life of iodine-131, all milk (500,000 gallons) within 500 square kilometers was destroyed for 3 weeks after incident.
- Determined that “Cockcroft’s Follies” filters helped to greatly reduce escaped radionuclides.
- Estimated to be released into the air during fire:
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The Long Slow Sludge
- Site officially decommissioned in 1980
- Pile 2 chimney partially demolished in 2001
- Decontamination scheduled to be completed past 2040