|Fig. 1: Photograph of the Sellafield nuclear fuel reprocessing site taken in 1993. (Courtesy of Simon Ledingham)|
Sellafield is a nuclear fuel reprocessing and currently a nuclear decommissioning site on the coast of the Irish Sea in Cumbria, England (See Fig. 1). Calder Hill, one of Sellafield's two nuclear reactor sites, was the world's first commercial nuclear power station. The other nuclear reactor site at Sellafield is known as Windscale. At first, Britain's nuclear energy program was used for solely military purposes. Windscale was originally used to produce the necessary plutonium to create and test an atomic weapon in 1952. But the British soon realized that their plutonium-producing reactors also had the ability to produce electrical power. By 1968, the UK was producing approximately 99 million kWh of electricity from nuclear power stations. In comparison, all other countries in the world were producing a total of approximately 62 million kWh - not even two thirds of the UK production. 
Just a year after Sellafield's two nuclear reactor sites began producing electricity for commercial reasons, one of the two reactor sites, Windscale, caught fire. This was and remains to Great Britain's largest nuclear reactor disaster. It has received a level-5 ranking on the International Nuclear Event Scale. In a routine heating of one of Windscale's piles the temperature in the reactor became too high, leading to combustion. The operators had used the Wigner annealing method for the reactor core. When the power ramped up, the temperature followed suit, and high temperature built up in the reactor's core. Unaware of how high temperatures had reached, the operators eventually let them exceed 400 degrees Celsius. By the time operators realized how significant the problem was, the fuel channels were already bright red, as aluminum casings around the rods were scorching. To fix the situation they attempted to turn on cooling fans; however, oxygen circulation caused the fire to further persist. 
The process of decommissioning a nuclear reactor site comes at the end of a reactor's typical 30- to 40-year lifecycle. There is an option of either refurbishing the reactor or decommissioning it. The latter involves cleaning the land so that it can be used for other purposes, not discarding it as a no mans's land that cannot be visited by humans due to health concerns. The reasons for which a reactor is decommissioned include cost, efficiency of nuclear power, and safety risks that come with having nuclear power close to civilization.  Sellafield is presently seen as no longer economically viable. The chief reason that the Sellafield nuclear sites are undergoing decommissioning is that other power options are more cost-effective for Great Britain.
Sellafield has a great place in the history of nuclear power. However, due to the heightening fears of the dangerous implications that come with a nuclear disaster and the ever approaching obsolescence of nuclear power, Sellafield will end up being decommissioned and put to a different use in the coming years.
© Henry Shimp. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 C. N. Hill, An Atomic Empire: A Technical History of the Rise and Fall of the British Atomic Energy Programme (World Scientific, 2013).
 "Aging Nuclear Power Plants: Managing Plant Life and Decommissioning," U.S. Office of Technology Assessment, OTA-E-575, September 1993.