Royal Society unearths top secret nuclear research
Only 66 years late
75 years of the neutron In his long-awaited energy white paper, published this May, Tony Blair opined that energy could be "as important to our future as defence".
According to secret documents, sealed during World War II, and unearthed by the Royal Society this year, it was ever so.
The papers have lain forgotten on a shelf in the Royal Society's archives since 1941, only to be unsealed this week to coincide with the 75th anniversary of James Chadwick's discovery of the neutron.
James Chadwick. Image credit: Godfrey Argent Studio
The sealed documents are scientific papers written by two physicists working in France in the late 1930s. They describe fundamental research into moderating the chain reaction in Uranium: research that was made possible in the first place by Chadwick's Nobel prize-winning discovery, and that paved the way for both nuclear reactors and the atomic bomb.
Keith Moore, head of the Royal Society's library and archives, describes the work as being on "the cutting edge" of nuclear energy research at the time.
He told us the papers were found by chance when someone noticed a 1940s style archive box gathering dust. When they opened it there was a letter signed by Chadwick attached to a series of envelopes sealed with red wax.
"We find old boxes like this quite often, but really the contents are usually pretty dull", Moore told us. "But we saw the Royal Society seals and realised we had something a bit unusual."
Piecing together the history, Moore says the two scientists, Hans von Halban (yes, he was actually German) and Lew Kowarski, most likely saw the writing on the wall in France. They moved themselves, their research, and their supply of heavy water over to Blighty.
They smuggled the entire global supply of deuterium (heavy water) across the channel, landing in Falmouth. The 26 steel drums they brought with them were sent to Wormwood scrubs, and then on to Windsor Castle Library.
The scientists joined the Cavendish Laboratory team and sent the work they had done in France to the British government. Eventually, the pair joined Tube Alloys, the British end of the Manhattan project based in Montreal.
The British government sent the papers on to the Royal Society, but not before leaving them to moulder on a shelf for a while. Peter Blackett, then a scientific adviser to the Ministry of Supply, and later a president of the Royal Society, wrote a covering letter in November of 1940:
"I enclose four short papers on questions concerning uranium fission...owing to the necessity of secrecy, they couldn't be published..."
After this rather stern admonishment, reminding the recipient of the importance of the research, he adds: "I fear I forgot about them for some months and have only now come across them again."
Blackett later said that if it had not been for the war, nuclear power would have been a French invention.
Chadwick's thumbprint - early biometrics?
While the early papers, written in French, have clearly come to the Royal Society from the British Government, others are in English, and were sent directly to James Chadwick who deposited them for safe keeping. These are sealed with with an impression of the great man's own thumb in red wax. [Early biometrics, you might say - Ed]
Chadwick also stressed the importance of secrecy, writing on 18 December, 1941: "I enclose..a paper entitled Technological Aspects of Nuclear Chain Reactions used as a Source of Power. The paper is such that it would be inadvisable to publish at the present time."
As to why the researchers would send the papers to Chadwick, and then on to the Royal Society, Moore says the scientists were not able to publish their work, but still wanted to make sure they could claim the discoveries as their own. He adds that this is in the oldest traditions of the society.
Dr Brian Cox, a particle physicist working at CERN, commented: "I can see why these papers were locked away during the war - they contain details that could be used to build a nuclear reactor."
Cox says the papers also provide an insight into "the inquisitive nature of scientists working in a field that was moving so rapidly it was almost outpacing them. It is fascinating to read their views on what might come of their research, and how accurate some of their predictions have been".
For instance, the two men hypothesise (correctly as it turns out) that a future industry of nuclear power would rely on uranium as its main fuel.
But what is also striking is what is missing: terminology that we might be used to today, the jargon of nuclear power. A nuclear reactor is referred to as "the boiler" throughout the papers. The moderator, material used to slow neutrons down, encouraging more of a manageable chain reaction and less of an explosion, is rather charmingly called "slowing-down material".
The intention was always that the papers would be unsealed and published after the war. But the pace of research was such that any ideas in the papers would have been quickly superseded. Cold War tensions could also have prevented their disclosure, Moore says. ®