It's been more than fifty years since the greatest nuclear disaster in Great Britain's history, the Windscale reactor fire in 1957. Now, with shrinking fossil fuel deposits and increasing energy demands, nuclear power represents a possible path forward. Is nuclear energy any safer now than it was fifty years ago?
The Construction of Windscale
The Windscale nuclear reactor was built in the early 1950s in an attempt to keep pace with the Russian and American nuclear weapon programmes. The British engineers did not feel comfortable with the principles utilized in early American reactor designs, and so instead of using water to cool the reactor they decided to use large quantities of blown air. In the Windscale plant design, air was sucked in with giant fans, forced through the nuclear core, and then expelled through a pair of large stacks. At the last minute (and at the insistence of Sir John Cockcroft) huge filters were installed at the tops of the stacks to trap radioactive material.
As the nuclear arms race intensified, the plant was pushed further and further beyond its intended specifications. Operating temperatures were increased and safety margins reduced in order to produce plutonium at an ever-increasing rate. With the invention of thermonuclear warheads, the core was modified to produce tritium as well as plutonium, and operating temperatures were increased again.
Fire at Windscale
On October 10th, 1957, engineers at the plant began to notice strange readings while performing a standard maintenance procedure on the core. Temperature readings that should have been falling were ambiguous, and a few were even rising. A physical inspection confirmed their worst fears – the nuclear fuel had caught fire.
Various methods were employed to fight the blaze. First, the engineers tried to manually push the burning fuel out of the reactor channels and into a water-filled collecting basin, where it could be extinguished. This was unsuccessful, as the burning fuel had melted and was now stuck inside the core. Increasing the flow of cooling air only fanned the blaze and spread more burning radioactive waste into the atmosphere. Desperate to stop the fire, they risked a devastating hydrogen gas explosion and used fire-hoses to fill parts of the reactor with water. This failed, and the fuel kept burning.
After 48 hours, temperatures were still increasing and threatened to exceed the failure point of the containment walls. As a final effort, everyone was evacuated from the facility and the ventilation was turned completely off. Without oxygen, the fire slowly withered and died.
Could it Happen Again?
The likelihood of a Windscale-type disaster occurring again is very small. Modern nuclear reactors are designed to produce electricity instead of material for nuclear weapons, and are not under the same political pressure to perform beyond acceptable limits. The air-cooled reactor design has also been entirely abandoned, as the Windscale disaster highlighted the possibility of blowing large amounts of radioactive debris into the atmosphere. Without the last minute design change that added filters to the Windscale plant, the disaster could have been much worse.
That being said, it is impossible to entirely eliminate human error from any design, as the 2005 incident at the Throp reprocessing plant shows. A leak went undiscovered for three months, and while no radiation was released into the environment, it also could have been much worse. In the end, the British public will have to decide if the risks are worth it.