The Windscale Piles were a set of nuclear reactors built by the British government on the northwest coast of England in what is today Sellafield, Cumbria. They weren't power-producing, but were instead commissioned to produce weapons-grade plutonium for atomic bombs. Construction began in 1946, with Pile no. 1 operational in October 1950 and Pile no. 2 in June 1951. The need for plutonium was urgent and the facility had some serious design flaws. They were meant to run for about five years.
The reactors themselves were each heavily-shielded stacks of graphite blocks with a series of vertical boreholes and hundreds of horizontal channels carved into the blocks in an octagonal pattern. The channels were used for inserting canisters filled with materials that were to be bombarded with neutrons- usually uranium that would be turned into plutonium- while the boreholes were where the reactor’s control rods, which controlled the fission rate by absorbing excess neutrons, were inserted.
Once enough metallic plutonium had been produced, the canisters would be pushed out through the back of the reactor into a water duct for cooling. On the front end, the entire reactor was cooled by a fan-driven air duct that passed air directly over the core and out through a 400-foot-tall chimney. The only real safety device in place for this was a filter at the top, an expensive last-minute addition of seriously questionable value.
The issue with the design was that, at lower temperatures, the graphite blocks would store up the energy from the neutrons in their crystalline structure. If left unchecked, this energy would be released in a spontaneous burst of intense heat. This was first noticed two years into Windscale's life and a new system was implemented to combat this: heating up the graphite to 250 Celsius to expand its structure and allow the stored neutrons to escape more gradually and safely.
This process, known as annealing, was performed every few months. The problem is that reactors weren't built for this process and the energy releases were completely unpredictable, but as more pressure was put on the overworked scientists at the facility and the improperly-placed safety devices told them there was nothing to worry about, they kept the process going. And so, during the annealing phase in October 1957, all hell broke loose in Pile no. 1.
Once the control rods were removed, the core quickly reached extreme temperatures. One of the canisters containing radioisotopes ruptured, spilling its contents. This caused the graphite— which usually can't burn in the air- to start smoldering. It wasn't until two days later, on October 10, that the operators realized what was happening, seeing all the needles still in the red.
The reactor was engulfed in white flames and molten uranium, and the operators had little idea of what to do at first. They tried to remove the cartridges with poles, which melted. Then they tried to pump in 25 metric tons of liquid carbon dioxide, but the heat actually split the carbon from the oxygen and made the fire worse. At its peak, the fire hit 1,300 Celsius and threatened to collapse the entire pile.
Finally, on October 11, the operators decided to pour huge amounts of water into the reactor. Due to the fears that contact with molten metal would oxidize it and give the fire a source of free hydrogen, the decision was made to also close off all air flow into the reactor. These decisions worked and the fire was quelled after another 24 hours, with direction and careful observation from above by the plant's own manager, Tom Tuohy.
In all, only around 20,000 curies of radiation were released in the environment in the form of Cesium-137, Iodide-131, and Xenon-133. Due to fears of contamination, milk from 500 square kilometers around the site was collected and disposed of for a month. The last minute addition of the filter actually proved valuable in ensuring no further contamination. On the Nuclear Disaster Scale, this ranks at a 5.
But as it was later found, the decision to shut off the cooling and air into the reactor was what really saved the day. Had this not been done, it's highly likely there would've been a meltdown or near-meltdown within just a few hours. The collapse of the pile would've resulted in massive contamination.
So what would've been the consequences had this not been the case? Maybe Tuohy makes a fatal miscalculation or just that the wrong decisions are made even earlier? What if Britain experienced a disaster on par with Chernobyl or Fukushima barely a year after the Suez Crisis? It's clear what the environmental effects are, but what would be the political, economic, and social effects, both domestically and globally?
The reactors themselves were each heavily-shielded stacks of graphite blocks with a series of vertical boreholes and hundreds of horizontal channels carved into the blocks in an octagonal pattern. The channels were used for inserting canisters filled with materials that were to be bombarded with neutrons- usually uranium that would be turned into plutonium- while the boreholes were where the reactor’s control rods, which controlled the fission rate by absorbing excess neutrons, were inserted.
Once enough metallic plutonium had been produced, the canisters would be pushed out through the back of the reactor into a water duct for cooling. On the front end, the entire reactor was cooled by a fan-driven air duct that passed air directly over the core and out through a 400-foot-tall chimney. The only real safety device in place for this was a filter at the top, an expensive last-minute addition of seriously questionable value.
The issue with the design was that, at lower temperatures, the graphite blocks would store up the energy from the neutrons in their crystalline structure. If left unchecked, this energy would be released in a spontaneous burst of intense heat. This was first noticed two years into Windscale's life and a new system was implemented to combat this: heating up the graphite to 250 Celsius to expand its structure and allow the stored neutrons to escape more gradually and safely.
This process, known as annealing, was performed every few months. The problem is that reactors weren't built for this process and the energy releases were completely unpredictable, but as more pressure was put on the overworked scientists at the facility and the improperly-placed safety devices told them there was nothing to worry about, they kept the process going. And so, during the annealing phase in October 1957, all hell broke loose in Pile no. 1.
Once the control rods were removed, the core quickly reached extreme temperatures. One of the canisters containing radioisotopes ruptured, spilling its contents. This caused the graphite— which usually can't burn in the air- to start smoldering. It wasn't until two days later, on October 10, that the operators realized what was happening, seeing all the needles still in the red.
The reactor was engulfed in white flames and molten uranium, and the operators had little idea of what to do at first. They tried to remove the cartridges with poles, which melted. Then they tried to pump in 25 metric tons of liquid carbon dioxide, but the heat actually split the carbon from the oxygen and made the fire worse. At its peak, the fire hit 1,300 Celsius and threatened to collapse the entire pile.
Finally, on October 11, the operators decided to pour huge amounts of water into the reactor. Due to the fears that contact with molten metal would oxidize it and give the fire a source of free hydrogen, the decision was made to also close off all air flow into the reactor. These decisions worked and the fire was quelled after another 24 hours, with direction and careful observation from above by the plant's own manager, Tom Tuohy.
In all, only around 20,000 curies of radiation were released in the environment in the form of Cesium-137, Iodide-131, and Xenon-133. Due to fears of contamination, milk from 500 square kilometers around the site was collected and disposed of for a month. The last minute addition of the filter actually proved valuable in ensuring no further contamination. On the Nuclear Disaster Scale, this ranks at a 5.
But as it was later found, the decision to shut off the cooling and air into the reactor was what really saved the day. Had this not been done, it's highly likely there would've been a meltdown or near-meltdown within just a few hours. The collapse of the pile would've resulted in massive contamination.
So what would've been the consequences had this not been the case? Maybe Tuohy makes a fatal miscalculation or just that the wrong decisions are made even earlier? What if Britain experienced a disaster on par with Chernobyl or Fukushima barely a year after the Suez Crisis? It's clear what the environmental effects are, but what would be the political, economic, and social effects, both domestically and globally?
