In the last few seconds of the countdown to the worlds first atomic bomb test in 1945,
many of the people there didn’t know if it was going to work.
Even General Groves, who had directed the Manhattan project said that as he lay on the
ground facing away from the test, he was thinking what he would do when the timer hit zero and
nothing happened. But of course as we know, it did work and
the world was changed for ever. But the US wasn’t the only country to have a nuclear
weapons program. In fact 5 countries active in World War 2 had nuclear programs and were
all working to make their own nuclear weapons, so how did we get to the Bomb.
From little acorns great Oaktrees grow and in the case of the atomic bomb, from subatomic
particles untold destructive power comes. However, like many things, the end result
was a world away from the initial research by a small group of international scientists
into the newly discovered effect of radiation in the last years of the 19th century.
It was this international nature of the work with scientists from France, Denmark, Germany,
Hungary, Soviet Union, Britain, United States and Japan which would spawn nuclear programs
in different countries, but it would the ability of those countries to muster the resources
and foresight of their leadership which would determine the winners.
In just over 40 years we had gone from the discovery of radiation to the theoretical
workings for atomic bomb but putting theory into practice was a very different proposition.
The practical creation of a sustained chain reaction was the goal, in a controlled form
as a nuclear reactor and the uncontrolled one as a bomb and both needed a material that
would be fissile, that’s something that could be triggered into a self-sustaining
nuclear chain reaction. In 1939 the only known material that could do this was Uranium 235
but the problem was just getting hold of enough of it.
99% of all the Uranium found on earth is Uranium 238 but it’s too stable and won’t create
a self-sustaining chain reaction. Uranium 235 can achieve this but it is much rarer.
For every 1 kg of Uranium 238 there is around 0.7 grams of Uranium 235 and while it can
be separated from U238 the process is very difficult and time consuming.
In 1939 with Nazi Germany’s annexation of Czechoslovakia, a worrying development was
noticed by scientists working in the US and England in that the sale of Uranium ore from
the now Nazi controlled Czechoslovakia had been stopped and the Purchase of heavy water
from Norway had increased. Also in 1939 German nuclear physicist Siegfried Flügge published
two influential articles on the exploitation of nuclear energy as a source of power.
Hungarian Leó Szilárd who was now in the United states and had conceived the idea of
the nuclear chain reaction in 1933 and the nuclear reactor with Enrico Fermi in 1934,
was so alarmed by this that he enlisted the help of Albert Einstein to write a letter
to the US president Roosevelt warning him that they believed the Nazis were working
on building a bomb with the explosive power to destroy entire cities, though at the time
they thought that such a bomb might be too large to carried by plane and instead would
be delivered by boat along a river or to a port.
Meanwhile in Britain, research into the possibility of making an atomic bomb had taken a dramatic
turn. Two German refugee scientists Rudolf Peierls and Otto Frisch who hadn’t been
allowed to work on the RADAR project because they were enemy aliens and didn’t have clearance
were tasked by Professor Mark Oliphant at the University of Birmingham to investigate
the chain reaction problem. They worked out that the critical mass, that’s
the amount of nuclear material required achieve a sustained chain reaction in a sphere of
pure Uranium 235, could be as low as 1 to 10 kg. This meant that a bomb could be made
small enough to be dropped from a plane and have the explosive power of thousands of tons
of TNT. The Paper Frisch & Peierls wrote was called
“Memorandum on the properties of a radioactive “super-bomb” but became known as the Frisch
& Peierls memorandum. For the first time, this not only set out what was needed to make
and atomic bomb but also the effects of having and using them would be. It pointed out the
effects of the nuclear blast and the radioactive fallout on civilians as well as combatants
and that if the enemy were to have atomic weapons there would be virtually no defence
against them, the only counter threat would be to have a similar bomb yourself as a deterrence.
They also thought that if they could have come to this conclusion then so could the
Germans This prompted the British government to create
the MAUD Committee in 1940 to study nuclear power and the creation of the “Tube Alloys”
project to make their own atom bomb. The upshot of this was that creation a working uranium
atom bomb was not only thought possible but it could be done in a couple of years.
But by the summer of 1940 Britain was under daily air attack from the Luftwaffe and resources
were scarce. It was feared that if the Germans invaded they could get access to the advanced
work that had been done, so Churchill authorised the sharing of the atomic bomb plans along
with other top secret British projects with the US were work could continue unhindered.
The Americans were surprised by how far much the British had proceeded with the research
as most of their research was into nuclear reactors and not weapons. This along with
a lot of cajoling by Mark Oliphant whom had shown them the Frisch & Peierls memorandum
and later from Churchill spurred them into creating the Manhattan project in Oct 1941.
But the German atomic bomb project which had been of such concern to the US and British
wasn’t faring quite so well even though it had been German scientists Otto Hahn and
Fritz Strassmann that had discovered nuclear fission in 1938 and German physicists such
as Werner Heisenberg and Carl Friedrich von Weizsäcker were regarded as leaders in their
field. Many believed that Germany not only had the
brains but with the occupation of Europe the means to develop an atomic bomb first but
instead the project never really gained much support with the German high command and Hitler
compared to projects like the V2 rocket which would have been the ideal delivery platform.
But the biggest effect was the politicization of the German education and university system
by the Nazi’s before the war and especially during it. This forced out many of the top
scientists that would later end up working in Britain and the US and on the Manhattan
project including Enrico Femi, Edward Teller, Klaus Fuchs, John von Neumann, Otto Robert
Frisch and Rudolf Peierls. Because many of the scientists were Jewish,
areas of nuclear physics like quantum mechanics were seen as Jewish science and denounced
by the Reich, something they would later acknowledge in 1943 as having a major impact on their
abilities but by then it was too late. Attacks on the Norwegian Heavy water facility
which were now in the hands of the Germans slowed research that was being done and by
1942 it was assessed by the Reich that nuclear fission would not have a significant enough
effect on ending the war and research was scaled back and scientific resources were
moved to more pressing wartime matters. After the war, German scientists said that the lack
of heavy water was a major factor in limiting their atomic program.
Now many have heard the term “heavy water” but the reason why this was so important to
the early atomic bomb programs is not because the water was radioactive, it wasn’t, it’s
because it has a larger amount of the hydrogen isotope deuterium which made atomically heavier,
hence the name. It’s the ability of this extra deuterium to slow down neutrons which
made of it of such great value. Uranium 235 can be triggered into a self-sustaining
chain reaction if it is bombarded with slow moving thermal neutrons. The heavy water works
as a moderator to slow down fast neutrons without absorbing them like normal water and
thus enables a nuclear reactor to work and a working reactor would be needed for research
into how to build an atomic bomb. What is not known by many is that the Japanese
also had an atomic bomb program. This was headed up by Yoshio Nishina who had studied
under Niels Bohr in Denmark in the 1930’s. This program was called the Ni-Go project
and was under the command of the Imperial Japanese Army.
Although they worked on Uranium refinement and they did little work on the actual bomb
design itself. After the Japanese Navy had conducted it own research with help from the
Imperial University in Tokyo, it was concluded that while an atomic bomb was theoretically
possible and that the US was probably working on it too, they believed it would be to difficult
even for the US to make a bomb within the timescale of the war.
The Japanese Army continued its research with the Ni-Go project but only managed to make
a small amount of material but was found not to be Uranium 235 and the building were the
work was carried out was destroyed by fire after bombing raids by the US air force.
Another issue that held the Japanese back was that they were working on their own and
didn’t share information with their German allies unlike the US and Britain and Canada
which worked together on the Manhattan project. In the end a lack of understanding about the
project by the Japanese military leaders and the subsequent lack of resources put paid
to the Japanese atom bomb project before the end of the war.
Meanwhile, The Soviet scientific community had discussed the possibility of an atomic
bomb through the 1930s but it was only after the war started did they create a nuclear
program. The soviets suspected that both the Germans and the Allies were working on a “super
bomb” but the German invasion of the Soviet Union, their nuclear research slowed to a
crawl as many of the top scientists where drafted into the military.
In 1940 Leonid Kvasnikov, a chemical engineer and NKVD operative noticed that research about
Uranium was being pulled from western publications leading him to believe that a breakthrough
had been made and they were working on a nuclear bomb. This information ended up on the desk
of Lavrentiy Beria, head of the NKVD, the Soviet secret police but he didn’t tell
Stalin straight away as he knew he was preoccupied with the war. Beria’s network of spies also
soon brought back information about the British breakthrough and the Frisch & Peierls memorandum
In 1942 Georgy Flyorov, a prominent Russian physicist serving in the Soviet Airforce wrote
to Stalin, warning him about the development of atomic weapons by foreign powers and that
the first country to have an atomic bomb would dominate the rest world. Stalin was fascinated
by the thought of a “super bomb” and setup an atomic bomb project and put Lavrentiy Beria
change and told him that he had five years to produce an atomic bomb or face the consequences.
Whilst the rest of the Soviet Union suffered shortages of men, materials and food, Beria
setup a secret town and put in the top scientists to work on the atomic bomb with no expense
was spared. Beria had two lists, one for those whom would get promotion for their work and
the other for those that failed, they would face the gulag or execution.
Beira’s use of spies to boost the Soviet bomb program with espionage that started in
the UK and spread to the US and eventually ended up with blueprints of the first US atomic
weapon being given to the Soviets. That and other valuable information about the Manhattan
project that was obtained from spies including Klaus Fuchs, Theodore Hall, Morris Cohen,
Harry Gold, George Koval and David Greenglass This espionage greatly shortened the time
it would have taken the soviets to develop a bomb on their own and helped them bypass
the time consuming and highly dangerous work like determining the critical mass which killed
two of the Manhattan Project physicists, Harry Daghlian and Louis Slotin.
It would take a further 4 years before the soviets exploded their first bomb called “First
Lightning” in 1949 and which was based on the American "Fat Man" design of the Nagasaki
bomb at the Semipalatinsk Test Site in Kazakhstan. Although the British had made an impressive
lead in the research it was soon overtaken by the US. By 1943 Britain had spent about
$1M on research, the US in comparison had already spent $1B. When the British saw the
resources being poured in, they gave up any hope of creating a weapon by themselves during
the war and Churchill pressed for full involvement in the Manhattan project.
In all the US spent about $2 billion, around $28 billion today on the project, one of the
biggest construction projects in US history with over 90% of that for buildings and facilities
to produce the fissile material Uranium 235 and later Plutonium 239, the only other known
fissile material and entirely man made in the core of a nuclear reactor. At its peak
production for the refining of Uranium, the power required was equivalent to 10% of the
entire US electrical supply. It was discovered that if Uranium 238 was
bombarded with fast neutrons it transmuted into Plutonium 239, a process that could create
much more material than the refining of Uranium for U235.
This had a huge impact on the project because it was taking so long to amass enough Uranium
235, it was thought there wouldn’t be enough material if more than a couple bombs were
going to be used by 1945. A new implosion design using Plutonium was
thought to be more powerful than the gun type Uranium bombs and would be able to be made
in much larger quantities, something that would be needed if the war dragged on and
as a show of force to the Soviets. The Trinity test used a Plutonium bomb while
the “Little Boy” bomb dropped on Hiroshima was the first Uranium bomb. Plutonium powered
the Nagasaki “Fat Man” bomb and became the standard fuel for atomic bombs and the
ignition device for the later hydrogen bombs for all the counties that continued their
nuclear programs after the war. Given the right conditions, access to Uranium,
resources and time, any of the above countries could have developed their own atomic bombs
but with the pressure of war, ideological dogma, lack of resources and just poor leadership
meant that the US was only ever going to be the winner in the race for the atom bomb.
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