By Dr Daxue Sun

Soon after the Windscale Pile 1 fire on 10 October 1957, Sir William Penny’s investigation report into the nuclear accident was delivered to the Prime Minister’s office. It noted that the steps taken to deal with the accident, once it had been discovered, were prompt and efficient and displayed considerable devotion to duty on the part of all concerned. The measures taken to deal with the consequences of the accident were also adequate. There had been no immediate damage to the health of any public or of the plant workers at Windscale, and it was almost unlikely that any harmful effects would develop. Penney accepted the fact that the isotope cartridges had spread the fire but insisted that the Windscale Team had been the primary cause of the accident because the second nuclear heating was started too soon and too rapidly. The trial and test procedures were strictly followed.

Windscale in the present

“What was the cause of the accident?” Penney was asked by the Windscale fire inquiry committee. “The cause of the accident was an error of judgement during a normal operation on the pile, called a Wigner release,” he replied. “Could such an accident happen at Calder Hall or any of the power stations that are being built for the electricity authority?” the board continued. “No, we are quite sure that a similar accident can’t happen to those reactors,” he replied. “You did say that you couldn’t quite remember whether it was you or not that put on the second nuclear heating? You reckon that was the right decision anyhow?” the board continued. “Yes, we’ve done this reheating several times before with no serious ill effects.” He replied.

Meanwhile the Prime Minister Harold Macmillan was travelling back from Washington to London with a great prize, the restored special relationship between the United States and Great Britain after the Suez Crisis of 1956 had threatened to divide the long-time allies. However, Penney’s report that now sat on Macmillan’s desk revealed that the creation of material for a Megaton bomb had fuelled the Windscale fire. On the night, Macmillan wrote, “How are we to deal with Sir William Penney’s report, to publish it to the world especially the Americans might put in jeopardy our chance of getting Congress to agree to the president’s proposal?” He made up his mind to recall all the copies of the Penny’s investigation report. The transatlantic relations proved to be mutually beneficial in history, though it was never an equal one.

In retrospect, the Americans had only wanted to keep the original earlier nuclear knowledge to themselves and had arrogantly ended the nuclear partnership with Britain in 1946. Nothing had guaranteed Britain’s future status as a world power by its relationship with America, even when the British scientists helped build the first atomic bomb in the Manhattan Project. The atomic bomb that had effectively ended World War II was regarded as the means of keeping the peace. From 1947, the massive engineering building of the first nuclear reactor at Windscale took an epic journey in order to reassert that Britain was still a world power in developing of the nuclear weapon programme. By August 1952 the first 132 grams of plutonium departed from Windscale to become a key component of the Britain’s first atom bomb. It was a triumph not just for Penny’s Team but also for the people who concentrated the special nuclear fuel material in Windscale.

Winston Churchill was confident that he could persuade the Americans to re-establish the special relationship and secure a place at the top table for Britain’s atom bomb, but things were moving forward surprisingly quick. America’s hydrogen bomb had delivered a huge blow to the British’s ambition on 1 March 1954, which was 10 times greater than the size of the British atom bomb. The White House realised that Britain ultimately couldn’t actually compete with the United States and the Soviet Union. The stakes were running high for Britain to influence the Americans. The pressure was publicly transitioned from the British government to Penney’s Team and the Windscale Team to produce the much desirable hydrogen bomb. This set the route to the near disaster because producing a hydrogen bomb required a new material called tritium. However, Windscale had only been designed to make plutonium. Thus, the Windscale reactors had begun behaving unpredictably as temperatures in the fuel channels would increase suddenly and dramatically. Great credit was given to the Windscale Team who worked tirelessly on adapting the site. Despite the considerable technical problems, Windscale met the target of delivering considerable quantities of tritium for the hydrogen bomb under a very tight schedule. Penney’s Team also announced the positive news that the blast of “Orange Harold” was almost near a Megaton. However, it wasn’t a real hydrogen bomb – though the government claimed to now have one in the newspapers. Macmillan was undaunted as he tasked Penney’s Team to prepare another hydrogen bomb test even though Windscale had reached the breaking point. The issue was that there was nobody to say no despite a warning of impending disaster from the scientists. The launch of Sputnik had spawned Macmillan’s fortune as suddenly America became nervous and vulnerable to a Soviet satellite attack over their blue sky. British timing was perfect! Macmillan seized this opportunity on the night of 10 October 1957. Just not knowing what might unfold. He would have had to change his script to Eisenhower from urging him to force Congress to accept Britain as America’s nuclear ally to explaining what a shame a fire started in Windscale in this very evening.

What had exactly happened that night in Windscale? The temperatures inside the fuel channels in Windscale had kept on creeping up at an alarming speed. If an aluminium cartridge did get perforated, then the burning cartridge would raise the temperatures dangerously over 800 degree centigrade. Under these critical conditions the graphite in the pile might burn. Windscale Pile 1 was a blazing inferno! No one in the Windscale Team had faced anything like this before. People at the plant tried every option of killing the fire. There was nothing else they could apply apart from the last hope of shutting the ventilation air down. The combustion fire magically disappeared without the fuelling oxygen. The accident could have caused much worse environment damage due to the radiation leak if the design was without the concrete filter, known as croft folly, installed on the top of the chimneys in retrospect. Windscale survived the worst world nuclear accident until Chernobyl. Thereafter, the Windscale reactors were permanently closed for decommissioning.

In considering this accident, Britain had greatly strengthened the safety and health organisation in the nuclear industry and had intensified research on various aspects of the things that came out from the reactor accident. This industry had given Britain a full range of nuclear weapons in the age of Sputnik. Britain was the only country in the world that had a full scale of working nuclear power stations for both the military and commercial purposes. Britain had learned from this accident.

On 8 November 1957 when the White Paper of The Windscale Fire was published, Britain detonated a genuine megaton hydrogen bomb. On 22 August 1958, the American President Dwight Eisenhower announced a moratorium on nuclear testing, effective on 31 October 1958. From then onwards Britain had ceased atmospheric nuclear testing.



Dr Daxue Sun (BSc, PhD, CEng FIMechE, CSci & FIScT ) is the principal engineer and the senior coordinator of industrial placement students, mechanical graduates and apprentices of Mechanical Capability of Sellafield Ltd. His role in Engineering Capability is to provide technical leadership, strategic management and tangible engineering solutions in design, analysis, assessment and structural integrity to the nuclear decommissioning process. In his spare time, Daxue is a contract columnist of a writing APP – Zine, and collectively has been writing and publishing in English & Mandarin over 150 articles in the last 3 years. He is a visiting foreign professor of Liaoning Science and Technology University, and a visiting foreign lecturer of Northeastern University in China.