The Manhattan Project was the project organized by the alliance members namely the U.S., U.K. and Canada to develop a nuclear weapon against the enemies. The project was initiated as a result of the speculation that Germany had been working on its nuclear technology and will soon be able to make a nuclear weapon.
The name of the project originated as a cover, the first proposed name was the “Development of Substitute Materials” proposed by Gen. Somervell but was turned down as it gave away too much about the project and raised suspicion. Considering the sensitivity of the situation Gen. Groves the military head of the project named it the “Manhattan Engineer District” which later became famous as the “Manhattan Project”
The entire project is based on the basic theory of Nuclear Fission; the process of splitting up of a nucleus into smaller fragments.
Fission occurs when a nucleus of high mass absorbs a neutron and disintegrates into two fragments of equal sizes, as a result two or three neutrons and energy is released. A related but necessary concept attached to the nuclear fission is of the chain reaction, it refers to the fact that the neutrons released as a result of fission produce fission in at least one more nucleus. The amount of substance required to trigger a chain reaction is known as the critical mass. (Stephens,189-240)
There are two types of chain reactions controlled and uncontrolled, controlled reactions are when the released neutrons can only produce fission with one more nucleus, this type of reactions take place in power plants for nuclear energy (Stephens , 156-165), while the uncontrolled reactions are when there is no control on the number of fission reactions that take place one after another and as a result an explosion occurs with enormous amounts of energy released enough to create catastrophes such as the devastation of Hiroshima and Nagasaki, this type of reaction takes place in the nuclear technology involved in warfare such as the nuclear bomb.
Fission and the weapon race
The foundation for the fission research was laid down by Rutherford after the conclusions drawn by of his famous gold foil experiment. He achieved the artificial disintegration of nucleus by bombarding alpha particles on a thin gold foil (Boon , 56-77 ), this was taken forward by numerous physicists around the world and it came to the level when Hungarian scientist Leo Szilard found out that bombarding a nucleus with a neutron can start a reaction that can be used in developing weapons of mass destruction.
At this time several political changes were taking place around the world especially in Europe, as Hitler became the chancellor of Germany many Jewish scientists fled their country and took asylum in the U.S. or U.K., the tensions grew and Hitler invaded Poland in 1939 igniting the World War II at this point the biggest concern of scientists all over was that what would the Nazis do with the nuclear technology.
Many including Albert Einstein wrote letters to Roosevelt the then president of the U.S. telling him their concerns and the threats posed if Hitler is able to achieve the nuclear weapons. (Gosling and U.S. Department of Energy 19-23)
Manhattan Project – The Initiation
The increased pressure from letters and threats speculated if the Nazis get such weapons accelerated the process and enhanced the desire of the allies to attain the nuclear weapon capability.
Dr Oppenheimer was appointed as the scientific director of the project by Gen. Groves, he was a professor of theoretical Physics at the University of California Berkeley and renowned for his scientific geniuses, he is known as the “Father of the Atomic bomb” for his achievements in the Manhattan Project. (Kelly , 112-119)
Operations and researches were conducted at three major sites the Hanford Site for plutonium production, Oak Ridge, Tennessee for Uranium enrichment and Los Alamos, New Mexico for weapons research and design, besides these sites researches were conducted at numerous site all three allied countries.
Two different techniques were used in making the renowned bombs ‘Little Boy’ and ‘Fat Man’ as different material was used for both.
‘Little Boy’ employed the gun technique, and uranium was used for the material. This method suggested that a mass of Uranium-235 to be fired into a another mass of the same material, once both the masses meet a burst of neutrons is introduced and a chain reactions initiates, the energy produced becomes so great that the bomb blows it self apart. (Gosling and U.S. Department of Energy 29-35)
‘Fat Man’ employed a different technique called the implosion technique. As plutonium was the main constituent of the bomb it was realized that with the kind if plutonium received from the reactors at Hanford a gun type technique is not feasible as desired result will not be achieved due to spontaneous fission. Hence implosion technique was employed suggested by Seth Neddermeyer, it stated that explosive charges must be used rapidly compress a hollow sphere of Plutonium to a density where it achieves the critical level and we get a nuclear explosion as a result. (Gosling and U.S. Department of Energy 55-59)
The biggest problem faced was the availability of Uranium-235 as it only constitutes 0.7% of the total Uranium naturally available while 99.3% is Uranium-238. For a fission reaction to take place we need to have Uranium-235 hence filtering techniques were employed to successfully attain the desired isotopes. The most successful technique was the Gaseous diffusion proposed by Franz Simon and Nicholas Kurti, this method was greatly used at the Oak Ridge Laboratories produced most of the Uranium-235 used for making the bomb.
Although the Manhattan Project was a success for the allies but sadly the weapons developed as a result had to be brought in use against the mankind. The Germans surrendered in May 1945, but the Japanese were still on war, the U.S. in an attempt to end the conflict quickly, approved the use of the nuclear weapons against Japan.
This did brought the war to an end but resulted in an unforgettable disaster that the mankind will remember for ages to come.
The U.S. planes targeted the strategically important targets of Hiroshima and Nagasaki, the selection of these targets was made on several grounds including their military significance, and also the number of POWs present (The Manhattan Engineer District , 95-120 ). ‘Little Boy’ was dropped on Hiroshima in the early hours of August 6, 1945, and in a matter of seconds almost the entire city was destroyed. The death toll of Hiroshima alone is said to be 140,000 by the end of 1945, 90% of the buildings in the city were either damaged or completely destroyed, the entire communication system was destroyed the Japanese authorities didn’t even know of the disaster until several hours had passed. Nagasaki came under attack on the morning of August 9, 1945. ‘Fat Man’ dropped was responsible for the loss of at least 80,000 human lives.
The damage done was not limited just to the days of the bombings, but the disaster continued over the years. We saw thousands of deaths over the years and disabilities due to the radiations emitted by the bombings.
Although the Manhattan Project was a success on materialistic grounds but the question still remains that is the loss of thousands of human lives justified to achieve the desired outcomes.
Boon, Phillip Burton. Ernest Rutherford and the Atom (Pioneers of science and discovery). Main Line Book Co , 1989.
Kelly, Cynthia C.. Oppenheimer and The Manhattan Project: Insights Into J Robert Oppenheimer, “Father Of The Atomic Bomb” (Manhattan Project). New Jersey: World Scientific Publishing Company, 2005.
Gosling , F. G. , and U.S. Department of Energy . The Manhattan Project: Making the Atomic Bomb. University Press of the Pacific, 2005.
The Manhattan Engineer District, The Atomic Bombings of Hiroshima & Nagasaki . BookSurge Classics , 2004.
Stephens, William E. Nuclear Fission And Atomic Energy . Inman Press , 2007.