The United Kingdom had an early lead in atomic weapons research. Tube Alloys, the mysterious code name of their project, was the first serious nuclear weapons research program. Tube Alloys was founded as a effort to counter possible German research into nuclear weapons, though Germany during the entire war barely got close to where Tube Alloys did in the two and a half years before all British nuclear research was merged with the US-led Manhattan Project.
These firsts include understanding that a device that used an enriched uranium mix with a high proportion of uranium-235 would make an atomic bomb carried by a plane possible. The original idea is that the device would be made out of natural uranium, weigh tons, and would be dropped in a harbor by a stealthy submarine. The Einstein-Szilard letter to FDR that prompted the Manhattan Project had proposed the same idea after Tube Alloys discovered a true bomb was possible. UK researchers were the first to synthesize plutonium in amounts over half a gram. They named it “plutonium”. Early German efforts never tried to give it an official name. They didn’t love element 94 the way Tube Alloys did. Tube Alloys built the first gas-diffusion uranium isotope separation machine. Tube Alloys understood that plutonium might be a shortcut to the bomb. Tube Alloys proved it was possible to use graphite as a neutron moderator to make plutonium instead of using insanely expensive heavy water.
In the first year after US entry into WWII, much of Britain’s high-tech research was transferred to the US, but there was much contention over over sharing data. Churchill would eventually agree to unfavorable terms. He wanted to get into the Manhattan Project while the British lead was still relevant, and he also wanted a bomb to use against Germany as soon as possible.
After the war, the US was reluctant to share Manhattan Project data. British scientists were enticed to stay in the US. Researchers who returned home were allowed only their personal notes. UK Prime Minister Clement Attlee was a miffed at this, but the Atomic Energy Act of 1946 which banned all sharing of nuclear data seemed like an official snub from the US.
Things didn’t seem so bad until the Soviet Union tested its first nuclear weapon in 1949. It seemed to Attlee that the UK would not remain a world power without an independent nuclear weapons program.
Here’s a 1997 documentary from BBC4 about that decision:
Don’t laugh at the plutonium core in the yellow barrel. The first few cores made in the US traveled a thousand miles in the back seat of a car.
There may be a few questions you have about this video. First off, it ignores uranium enrichment and focuses on plutonium production at Windscale. As I have pointed out the Manhattan Project spent over half its budget for uranium enrichment at Oak Ridge. This UK project was much more efficient. It used the gas diffusion proccess, the most efficient of the Oak Ridge programs, and they never attempted to make bomb grade uranium. They went straight for moderately enriched uranium to make plutonium.
This is just how the Soviets were able to get the bomb in 1949. They skipped the Little Boy linear uranium device, and used only gas diffusion separation to make moderately enriched uranium to turn into plutonium. It’s almost like the UK and USSR bomb programs were led by the same person.
They were, Klaus Fuchs. Fuchs fled Germany for the UK, was recruited into Tube Alloys, and built the first gas diffusion uranium seperater. He went on to supervise gas diffusion at Oak Ridge in the US and would eventually become Teller’s assistant at Los Alamos.
Churchill briefly became PM again in the early fifties. When Attlee told him his little secret that the UK was just a couple of months away from an atomic test, I am sure Churchill was pleased as punch about this little secret.
There was a pretty serious accident at Windscale in 1957. If you watched the video you know that those massive filtered stacks pumped air through the first ever air-cooled graphite breeder reactor. Windscale was pressed into hard service them because the first British thermonuclear test had been a dud. There was a plan to make a boosted fission device higher yield and lighter than the US Ivy King device, the largest fission bomb ever detonated in case their second H-bomb failed. This boosted fission bomb was never built because air cooling and neutrons do not mix well.
Please remember the cows of Windscale
These cows were tested to see if they had absorbed radioisotopes, driven off their grazing lands and fed hay and feed from far away while being milked and having their milk diluted with water and dumped into the sea so that milk with radioactive iodine would not get into the food supply.
Long scale studies of the Windscale fire have shown that maybe 240 people have gotten cancers they would not have otherwise.
All this supports my hypothesis that living near nuclear processing facilities is more dangerous than above-ground nuclear testing. And all of this is peanuts compared to other public health risks. The cars we drove in the nineties killed more of us just here in the US. The 2003 auto safety bill has saved more lives just here in the US than have ever been lost to nuclear testing.
The future of UK Bombs:
In 1958, after the UK had detonated it’s second and fully successful hydrogen bomb, the US would agree to full nuclear secret sharing with the UK. As I noted here it seems that the UK program moved to Nevada in the late sixties.
Attlee and Churchill were long gone by that time. I don’t know how this came to be.