Nuclear Leaks 8: Sellafield aka Windscale

The Sellafield facility on the Cumbrian coast, United Kingdom (May 2005). Image Source: Visit Cumbria via Wiki.

In 2005, Britain experienced a significant nuclear accident that was not widely reported in the UK.  The story was initially covered in the German press. Wiki: "At Sellafield, 20 metric tons of uranium and 160 kilograms of plutonium dissolved in 83,000 litres of nitric acid leaked over several months from a cracked pipe into a stainless steel sump chamber at the Thorp nuclear fuel reprocessing plant. The partially processed spent fuel was drained into holding tanks outside the plant." BBC has further details:

A leak at the Sellafield nuclear reprocessing plant in Cumbria was not spotted for three months, an investigation has revealed. More than 20 tonnes of uranium and 160kg of plutonium spewed onto a floor when a pipe fractured at the Thorp reprocessing complex in January. The British Nuclear Group, which carried out the inquiry, stressed that the material leaked into a sealed cell. The discovery was made after a camera inspection of the cell in April.

It was classified as a level 3 accident by the International Nuclear Event Scale (INES) because of the acid released in the incident. INES measurements listed the 1986 Chernobyl disaster as a level 7 incident and Three Mile Island in the United States in 1979 as level 5.

The leak occurred when a pipe - just a few centimetres wide - fractured, sending nitric acid onto the floor of the concrete-lined cell. The cells, which are 60 metres long and 20 metres high, are not accessible to staff and no-one was exposed to radioactive material.  According to the British Nuclear Group's findings, the pipe failed because of metal fatigue, which may have started to occur as early as August 2004. The report recommended that improvements be made to the maintenance and testing procedures at Thorp, which remains closed since the leak.

Complacency addressed

Detailed reviews into engineering and operating practices throughout the plant should also be conducted, it concluded. Barry Snelson, Managing Director at Sellafield, said: "I will personally be ensuring that recommendations are implemented not just in Thorp, but across Sellafield. "I am disappointed that plant indicators were not acted upon as quickly as they should have been and I shall be taking action to ensure that any complacency with respect to acting upon plant information is addressed." Sellafield staff are confident that Thorp can be returned to service, he added.

Blind luck prevented this from becoming a more toxic event. Sellafield had already five more serious incidents between 1955 and 1979. Thorp started up again in 2008, the same year that the British government issued the whole Sellafield complex an unlimited indeminity against future accidents. An American, French and UK consortium was awarded a huge contract to decommission Thorp over five years, starting in 2010.

The 1957 Fire

Formerly known as Windscale, the facility had a frightening accident in 1957. That crisis ranked at level 5, a disaster on par with Three Mile Island, Chalk River, and the Goiânia accident in Brazil.

The Windscale fire was the worst nuclear disaster in British history. The facility was built to refine plutonium. In the intense international nuclear competition of the Cold War, the priority at Windscale was making atomic bombs; electricity was only a sideline, a sweetener for the public. This is a story of Britain struggling to keep up with America as she slipped from her preeminent international position after the Second World War. According to the BBC, Prime Minister Harold Macmillan felt intense pressure to cultivate American friendship by demonstrating that British nuclear capabilities were on par with America's. As a result, plutonium and tritium production at Windscale was intensified past the plant's capabilities. Development of tritium, especially, pushed the original design of the plant beyond its limit, causing it to overheat. On 10 October, the core of the reactor caught fire. The terrifying fact slowly dawned upon personnel:

Tom Hughes, second in command to the Reactor Manager, suggested examining the reactor personally and so he and another operator went to the charge face of the reactor, clad in protective gear. A fuel channel inspection plug was taken out close to a thermocouple registering high temperatures and it was then that the operators saw that the fuel was red hot.

"An inspection plug was taken out," said Tom Hughes in a later interview, "and we saw, to our complete horror, four channels of fuel glowing bright cherry red."

There was no doubt that the reactor was now on fire, and had been for almost 48 hours. Reactor Manager Tom Tuohy donned full protective equipment and breathing apparatus and scaled the 80 feet to the top of the reactor building, where he stood atop the reactor lid to examine the rear of the reactor, the discharge face. Here he reported a dull red luminescence visible, lighting up the void between the back of the reactor and the rear containment. Red hot fuel cartridges were glowing in the fuel channels on the discharge face. He returned to the reactor upper containment several times throughout the incident, at the height of which a fierce conflagration was raging from the discharge face and playing on the back of the reinforced concrete containment—concrete whose specifications required that it be kept below a certain temperature to prevent its disintegration and collapse.

Windscale staff struggled to put out the fire. They tried carbon dioxide and water without success - and soon were facing 11 tonnes of blazing, white-hot molten uranium. Finally, the fire was extinguished by cutting the air supply, and the reactor sealed, leaving 15 tonnes of uranium inside. Fallout was released across the UK and Europe, including large quantities of Iodine-131, Caesium-137, and Xenon-133. In 1981, the facility was renamed Sellafield. According to Wiki, the "pile [from the 1957 accident] is not scheduled for final decommissioning until 2037." Some salvaging of nuclear fuel from the site is underway from 2008 to 2012. 

The documentary below, Windscale: Britain's biggest nuclear disaster, was originally broadcast on Monday, 8 October 2007, at 2100 BST on BBC Two.  It explains the disaster in detail.

Windscale, Part 1. Video Source: BBC via Youtube.

Windscale, Part 2. Video Source: BBC via Youtube.

Windscale, Part 3. Video Source: BBC via Youtube.

Windscale, Part 4. Video Source: BBC via Youtube.

Windscale, Part 5. Video Source: BBC via Youtube.

Windscale, Part 6. Video Source: BBC via Youtube.

Windscale, Part 7. Video Source: BBC via Youtube.

Windscale, Part 8. Video Source: BBC via Youtube.

Windscale, Part 9. Video Source: BBC via Youtube.

Leaks and Nuclear Waste Storage Issues

Wiki: "Between 1950 and 2000 there have been 21 serious incidents or accidents involving some off-site radiological releases that merited a rating on the International Nuclear Event Scale, one at level 5, five at level 4 and fifteen at level 3. Additionally during the 1950s and 1960s there were protracted periods of known, deliberate, discharges to the atmosphere of plutonium and irradiated uranium oxide particulates. These frequent incidents, together with the large 2005 Thorp plant leak which was not detected for nine months, have led some to doubt the effectiveness of the managerial processes and safety culture on the site over the years."

In 1994, Greenpeace supporters broke into the nuclear waste dump at Drigg in Cumbria and investigated the repository's conditions.  See the video below.

Video Source: Youtube.

Organ Removal and Cold War Experiments Controversy, 2007-2010

In 2007, an inquiry was launched to investigate the unauthorized removal of tissue samples from deceased nuclear workers, including some Sellafield personnel. On 22 April 2007, Jamie Doward reported for the Observer that "during the 1960s volunteer workers at Sellafield had participated in secret Cold War experiments to assess the biological effect of exposure to radioactive substances, such as from ingesting caesium-134."

The result? The recent BBC Two documentary on Windscale sums up these circumstances well: "A new Britain was emerging. The trust between leaders, scientists and men which had been forged in wartime had begun to disappear." A timeline of Sellafield events is here.

See all my posts on nuclear topics.


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