After the successful test of a plutonium implosion device in July of 1945 at the Trinity site near Alamogordo, New Mexico, the Manhattan Project proceeded with the design and construction of a plutonium bomb to be used as a weapon. The code name for the device was “Fat Man”, homage to one of the characters in the movie “The Maltese Falcon.” The name came to be used for the whole class of nuclear bombs based on the same design.

           The original Fat Man bomb was about ten feet long and about five feet in diameter. It weighed over ten thousand pounds. As with the Gadget, the device tested at Trinity, a subcritical sphere of plutonium was surrounded by both fast and slow explosives. When the explosives were triggered, they would compress the plutonium into a supercritical mass which would then explode in a nuclear blast of enormous power.

           The bomb was designed so that the plutonium pit could be inserted as late as possible. A Duralumin sphere of about one and one half feet was constructed with a hole left to insert the pit. Inside the aluminum sphere was a nine inch sphere of U-238 with a thin boron shell. The U-238 sphere had a five inch cylindrical hole running through it. When it was time to arm the bomb, a cylinder of U-238 with a three and one half inch sphere of plutonium was inserted into the spherical assembly. At the center of the plutonium sphere was a polonium-beryllium initiator that would give off a burst of neutrons when triggered. An outer shell of specially shaped charges of fast conventional explosives surrounded an inner shell of slow conventional explosives which contained the Duralumin sphere. On the outside of the shell of charges were arranged detonators in a precise configuration. The charges had to be triggered in just the right way to compress the plutonium correctly.

           The completed bomb was housed in a steel container that also contained four contact fuzes in the nose. This type of fuse triggers the bomb when it hits a hard solid surface. There was also a radar altimeter, batteries to power the detonators for the conventional explosives, baroswitches that trigger based on air pressure and timers. The whole assembly was to be housed in a steel teardrop shaped container that had a boxy tail piece to assure that the bomb would fall nose down when released. In August of 1945, all the components were sent to Tinian Island in the South Pacific and assemble for deployment.

            This was the third nuclear bomb to be constructed and the second bomb to be used in warfare. Later generations of bombs were based on the Fat Man design with additional features to make them more reliable, safer, more efficient, etc. When the Soviet Union built and tested its first nuclear bomb on August 29, 1949, the design was  based on the plans for the Fat Man bomb which had been stolen by spies from the United States.

           While the Manhattan Project was developing plutonium production facilities and producing plutonium at Hanford, Washington in the early 1940s, the Project was also working on the design of a bomb that would utilize the plutonium. It turned out that gun-type design being worked on for a uranium bomb would not work for a plutonium bomb. Plutonium-239 was being produced in reactors but the reactors were also creating plutonium-240 as well. P-240 spontaneously fissions and produces neutrons. In a gun-type bomb, these extra neutrons would cause the bomb to explode early before a full critical mass of plutonium was formed. The resulting fizzle blast would be much weaker than a full nuclear explosion.

           After ruling out the gun-type bomb design, work was begun in 1944 at Los Alamos, New Mexico n a new implosion bomb design. The design was based on a sphere of plutonium with a neutron initiator at its core. The sphere was to be surrounded by conventional explosives that had different burn rates. When arranged properly and triggered in the right time sequence, the explosives would create a compression wave focused inward. This compression wave would compact the plutonium sphere into a smaller sphere that was much denser than the original sphere. Because the critical mass is a function of density in a volume, the amount of plutonium would be a critical mass in the smaller sphere. The neutron initiator was included to insure that the reaction triggered properly.

          On benefit of this design was that it required much less plutonium than the amount of uranium needed for a gun-type bomb. The implosion design only required about fourteen pounds of plutonium. The new design was very complex and pushed the state of the art for creating a compression effect. While the gun-type design was simple and reliable enough that it was not felt that a test was needed, the implosion design was so new and difficult that it was decided to create and test such a bomb before deploying it as a weapon. The test bomb was code named “the Gadget.”

          The Gadget was constructed and a new test site was created in New Mexico near Alamogordo during the first half of 1945. Laboratory leader J. Robert Oppenheimer named the site Trinity in reference to a poem by John Dunne. A one hundred foot steel tower was constructed for the test to simulate the air burst of an actual bomb to maximize effect. The components were assembled in July of 1945.

          Early on July 14^th, 1945, the Gadget was detonated in a blast equivalent to twenty kilotons of TNT. The blast created a crater of radioactive glass below the tower. The shock wave was felt over one hundred miles away. The mushroom cloud towered to about eight miles in the sky. The very first nuclear blast ever created by the human race lit up the surround mountains brighter than the sun and awed everyone who directly witnessed it. There were a number of reports in the area of a huge bright explosion which was explained as the explosion of an ammunition magazine to the media. Oppenheimer later remarked that he was reminded of a passage in the Hindu Bhagavad Gita; “Now I am become Death, the destroyer of worlds.”

This is a photograph of the Trinity fireball sixteen milliseconds after detonation:

         In the summer of 1945, the United States Manhattan Project to create an atomic bomb delivered  one hundred and ten pounds of uranium enriched to 89% U-235 too the Los Alamos testing grounds in New Mexico.

            A design had been developed for a uranium bomb. The bomb consisted of a tube that was ten feet long and about two feet in diameter. At one end of the tube there were bags of cordite explosive behind a hollow cylinder of stacked uranium rings. At the other end of the cylinder, there was another smaller cylinder of uranium rings stacked on a steel rod. The smaller cylinder would fit snugly inside the hollow cylinder and it had a polonium-beryllium neutron initiator behind it.  Both cylinders of uranium were surrounded by tungsten carbide to reflect neutrons.  

           When the explosive was fired, it would propel the hollow uranium cylinder along the tube to engulf the smaller uranium cylinder at the other end of the tube, creating a critical mass of uranium that could undergo fission. The neutron initiator release a burst of neutron when the bomb was triggered. The neutron burst would cause a runaway chain reaction in the uranium and an explosion would result. The actual explosive power of the bomb was highly dependent on the way that the critical mass was configured. If only one percent of the uranium in t he bomb fissioned, it would create an explosion equal to thousands of tons of TNT. On the other hand, if the configuration was off or the impact of the two pieces of uranium too slow, the bomb would just explode with the power of a few tons of TNT.

          The components of the bomb were assembled in the winter of 1945 before the uranium was available. It was decided that the design was so reliable that it was not necessary to actual blow up such a bomb to test it. There was a lot of work in the laboratory however to verify that the design concepts were correct. When the uranium arrived in the summer of 1945, the bomb was assembled and ready for use. It was named “Little Boy”. The name was in contrast to a “Thin Man” alternative design which would have been seventeen feet long. The “Thin Man” name came from the detective novels of Dashiell Hammett. It turned out that it was not necessary to make such a long bomb.

         The Little Boy gun design was only used once as a weapon. It was a very reliable design from the point of view of detonation but was not very safe. If the plane crashed, the two uranium charges could be driven together and explode. An electrical short circuit could trigger it. If a plane crashed in water, it could be triggered by water getting into the detonator. And, in water, the uranium charges would be subjected to a moderator effect leading to fission. Later nuclear bombs incorporated more safety features.

           While the U.S. Manhattan project refined and enriched uranium for an atomic bomb in the early 1940, a parallel project was carried out to create plutonium. Plutonium is very rare in nature so it was necessary to create nuclear reactor in which plutonium could be generated by injecting neutrons into a mass of uranium. Most naturally occurring uranium is the U-238 isotope. When U-238 is bombarded with neutrons, some of it is converted to U-239 by absorption of a neutron. The U-239 immediately decays into neptunium-239 by a neutron emitting an electron which leaves behind a new proton. This process occurs again to create plutonium-239. A very small amount of plutonium results from this process and it must be chemically separated from the unconverted uranium and purified.

          In March of 1943, the air cooled X-10 Graphite Reactor was built at the Oak Ridge facility in Tennessee. It consisted of a huge block of graphite that measured twenty four feet on each side. That cube was encased in seven feet of dense concrete as a radiation shield. There were initial problems with finding a way to encase the uranium slugs with a sealed metal shell to prevent corrosion and release of fission products. Several different approaches were tried and ultimately aluminum cans were welded with new techniques were developed. About thirty six tons of uranium were fed into the new reactor and half a gram of plutonium was created within the first month of operation. The reactor continued to produce plutonium for the Manhattan Project for the next year and was retired early in 1945.

          While the X-10 was in production, work proceeded at the Hanford facility in Washington on the more advanced water cooled Reactor B that would be water cooled. Six reactors were planned altogether. They were housed in buildings that were one hundred and twenty eight feet high. A total of eight hundred and thirty eight uranium slugs were inserted into Reactor B in mid-September of 1944. In late September, after the reactor had gone critical and fission had begun, the control rods were withdrawn to begin plutonium production. The reactor ran for a while but then the power level dropped and the reactor stopped. It turned out that Xenon-135 being produced during the reactor operation was poisoning the reaction by absorbing neutrons. By loading all two thousand tubes in the reactor, proper functioning was achieved and plutonium could be produced.

         Chemists had been working on the problem of how to separate the plutonium from the uranium. Little was known about the chemical properties of plutonium so a lot of basic research was necessary. A process was developed that involved bismuth phosphate that allowed precipitation of plutonium or precipitation of the uranium and impurities from solution. The separation plants consisted of four different buildings which housed a process cell, a concentration building, a purification building and a magazine store. Construction began in April of 1944 at Hanford before final choice of a processing method. New methods of remote control had to be developed to deal with the radioactive materials going through the sequence of buildings. In February of 1945, the first shipment of about two and one half ounces of ninety five percent pure plutonium was sent to the Los Alamos facility in New Mexico.

X-10 Graphite Reactor:

           After the Japanese attacked Pearl Harbor in December of 1942, the Manhattan project ramped up with millions of dollar and thousands of staff. Four major deposits of uranium ore had already been identified and efforts were being made to obtain ore from the three that were in Allied hands. In November of 1942 it had been determined that there should be sufficient ore available to produce an atomic weapon. Ore from the Belgian Congo, Ontario, Canada and a mine in Colorado was being collected during 1942.

          The ore was dissolved in nitric acid to produce uranyl nitrate. Ether was added to the solution to remove impurities. The solution was then heated to produce uranium trioxide which was ultimate reduced to pure uranium dioxide. The Ames process was developed to produce pure uranium metal after other methods failed. Uranium dioxide was converted to uranium tetraflouride which was mixed with powdered magnesium and heated in a sealed metal tube to produce pure uranium metal.

          The big problem was separating the U-235 isotope from U-238. Only .7 % of uranium ore is U-235. It was estimated that the percentage of U-235 needed to create a bomb was around 90%. Research and development of separation methods proceeded during the early 1940s.

           Converting uranium to uranium hexafluoride gas was a necessary first step in isotope separation. In a centrifuge, gas with the lighter isotope would move further than the heavier isotope. Feeding the output of one centrifuge into the next would theoretically allow the needed enrichment. Unfortunately, attempts to use centrifuges for separation were unsuccessful due to technical problems with running the big centrifuges at very high speeds for extended periods of time.  

           Electromagnetic separation was a known technology which used magnetic fields to deflect charged particles based on mass. Copper was in short supply so tons of silver were used instead to build production systems. Despite mechanical problems and efficiency, this process was used to enrich uranium to 15% U-235.  

           The third process was based on the idea that gases of different molecular weight will pass through membranes at different rates. With one chamber feeding the next, a cascade of these cells could enrich uranium hexafluoride gas up to 7% U-235. This resultant product could be used to feed other processes such as the electromagnetic separation system.

           The final process developed was referred to as thermal diffusion. When there is a vertical thermal gradient in a chamber full of a mixture of gases, the heavier gas will concentrate in the lower cooler part of the chamber and the lighter gas will collect in the warmer upper part of the chamber. This was a new idea and was not part of the original attempts to separate isotopes of uranium.  Fifty foot columns with three tubes were constructed. Steam and water created the thermal gradient. This process was able to enrich uranium from .7% U-235 to .9% U-235.

          In 1945, all three of these processes were used in series to enrich uranium. The thermal diffusion plant enriched uranium from .7% U-235 to .9% U-235. This was fed to the gaseous diffusion plant where the enrichment reached 23% U-235. The gaseous diffusion plant fed the electromagnetic separator which enriched to 89% U-235 which was sufficient for weapons production.

Electromagnetic isotope separation “racetrack”:

       The Manhattan Project was started in 1939 by the US Government to explore the military potential of uranium. The knowledge that the Germans were working on nuclear weapons research at the same time spurred the creation of the program. It started with a modest budget and a small group of researchers. In the meantime, Brittan was also pursuing nuclear research and verified in 1939 that fifty pounds of uranium could be made into a bomb that could be carried in a conventional bomber.

           World War II began in 1939 with the German invasion of Poland. Brittan created their own atomic bomb project in 1940. Information on their research was forwarded to the United States. Having received no reaction to their information, a member of the project flew to the United States and visited physicists doing nuclear research.

           In 1941, the President moved forward to create a major project dedicated to creating an atomic bomb as quickly as possible. The attack on Pearl Harbor in December of 1941 and the declaration of war with Japan and Germany added urgency to the project. The Manhattan Project was charged in 1942 with the task of developing the infrastructure necessary to building an atomic bomb.

           Millions of dollars were allocated and the project was carried out at a number of different sites around the United States. The first major problem that had to be solved was how to separate the U-235 isotope from uranium ore which consisted mostly of U-238. Three different techniques were pursued. Research was also done on the newly discovered radioactive element plutonium as a possible alternative to U-235. Finally, graphite was investigated as a possible moderator to control nuclear chain reactions. The Germans were also working on graphite moderation but their graphite rods contained boron which reduced their effectiveness. U.S. researchers created rods without boron and they worked as expected to control the reaction.

            Many physicists worked on theoretical problems of neutron diffusion and possible designs for an atomic bomb. The main approach was to create a sphere of U-235 which would exceed the critical mass and result in an explosion. The problem was how to arrange the parts of the bomb so that the sphere was created when the bomb was triggered. One idea was to shoot a plug into a subcritical sphere. Another was to use shaped charges to slam segments of a sphere together. When the critical mass was achieved, a runaway chain reaction in the U-235 would cause it to fission, creating a huge explosion.

           Physicist Edward Teller proposed a more powerful nuclear bomb which he called a hydrogen bomb. His idea was to use an atomic bomb as a trigger to cause deuterium and tritium to undergo nuclear fusion. The resulting explosion would be much more powerful than that atomic trigger. Teller pushed hard to build such a bomb but all his proposals were turned down in favor of creating a fission bomb.

           Radioactive elements were first isolated and studied around 1900. In 1933, Leo Szilard, a Hungarian physicist, was the first to suggest that the chain reaction of radioactive elements could be used to construct a bomb. He left Hungary for Berlin in 1919 and studied at the Institute of Technology under people like Albert Einstein. He got his doctorate in physics in 1923 from Humboldt University of Berlin. He worked as a physicist and inventor in Berlin for the next decade.

           On a trip to London in 1933, Szilard read a paper that was critical of the idea that atomic physics could be harness to produce energy. He was so annoyed with the tone of the article that he conceived of the idea of a nuclear chain reaction. If a neutron could trigger a nuclear reaction that produced a neutron, a self-sustaining chain reaction could occur. He returned to Berlin and began research to produce such a chain reaction. In 1036, he filed a patent for his idea with the British Admiralty.

           In 1938, Szilard was invited to do research at Columbia University in Manhattan, New York. He was shortly joined by Enrico Fermi who he knew from Berlin. In 1939, a group of researchers in Germany announce that they have achieved nuclear fission with uranium.  Szilard and Fermi conducted their own experiments with uranium and were soon able to produce neutrons that multiplied as the reaction progressed, proving that a nuclear chain reaction was possible.

          The knowledge the Germans were working on a nuclear chain reaction that could be used to create a devastating weapon was a great concern to Szilard. He drafted a letter to the U.S. President, Franklin D. Roosevelt. He talked Albert Einstein in to cosigning the letter. This was ironic because Einstein was a famous pacifist. The letter outlined the possibility of nuclear weapons, the fact that the Nazis were working on the problem and the need for a nuclear research project in the United States to develop such a weapon. The letter was drafted in August of 1939. In September of 1939, Germany invaded Poland. This invasion is often seen as the start of World War II. The letter was not presented to Roosevelt until October of 1939.

          Upon receiving the letter from Szilard and Einstein, Roosevelt created the Advisory Committee on Uranium. The Committee met quickly and authorized six thousand dollars for Fermi to do neutron experiments at the University of Chicago. The Committee did not pursue uranium research vigorously. Other organizations took over control of the research. Meanwhile the Germans were getting close to a controlled chain reactions but they made a mistake in the composition of the graphite rods they were trying to use to absorb neutrons and control the reaction. Szilard realized that the problem was impurities and made graphite rods that were free of the impurities. The new rods worked as expected and in December of 1942, his team produced the first human controlled chain reaction. In 1942, the Manhattan Engineering District took over the program which became known as the Manhattan project and was dedicated to the create of nuclear bombs.

Leo Szilard:

             The Tuareg are a nomadic people who inhabit the Sahara desert in Northern Africa. Most Tuareg live in Niger or Mali but they do move their herds across national borders in that area. They resisted the French invasion of their territory but lost and signed a treaty in 1917. Fighting continued until 1922 when the Niger became a French Colony. The northern part of Niger is traditional Tuareg territory while the southern part consists of Hausa tribal lands.

             Uranium was first discovered in the northern part of Niger in 1957. Further exploration uncovered additional deposits of high-grade uranium ore. The first uranium mine began production in 1971 under the control of Areva, a company owned by the French Government. The city of Arlit was created to serve the mine. Additional mines were opened. Niger became independent of France in 1980.  Today, the two main uranium mines in Niger provide about seven percent of the world’s uranium production. Most of the uranium produced in Niger goes to fuel reactors in Europe. Niger is the Saudi Arabia of uranium.

           About eight thousand people live in the two cities created by Areva to service the mines. The mine has produced millions of tons of uranium mine tailing which are piled up near the cities and exposed to the weather. The red dust, containing radioactive materials, blows down the streets and coats the buildings.  

            A Tuareg who created an organization to fight for the rights and health of the Tuareg started working in the mines in 1978. After work, he would go home and play with his children in clothing covered with radioactive dust. The first time that this man heard about radioactivity was in 1986 after the Chernobyl disaster was publicized.  After that he was giving a paper mask for protection from the radioactive dust in the mine. Eventually, a lung ailment forced him to quit working. Many of the Tuareg have died from mysterious illnesses. The hospitals which are owned by Areva are vague about the causes of the illnesses and death among the Tuareg around the mine. The company claims that there is no proof that people are dying because of work related radioactive exposure but some cases of cancer have been documented by outside physicians. There is evidence that there was a policy at the company hospital of deliberately not telling mine workers that they had cancer.

           In 2010, a team from Greenpeace went to Arlit with Geiger counters. They found dangerously high levels of radioactivity in the air, water and dirt that were hundreds of times above the normal level. Radioactive waste from the mines was used as a construction material for buildings and roads. People even used radioactive scrap metal for cooking pots. Well-water is contaminated. The uranium mines are using huge quantities of ground water and the pastures that the Tuareg depend on to feed their herds of cattle are disappearing.

           Politically, the Hausa dominate the country and have turbulent relations with the Tuareg in the north. One third of the children in northern Niger are malnourished and many die from diarrhea and pneumonia.  Tuareg citizen groups claim that the little money that Areva gives Niger for the uranium stays in the south or even winds up in the pockets of the President and his friends. The north gets nothing in return for the devastation of their lands but radioactivity that will last of thousands of years.

          Some Tuareg organizations have been negotiating with Areva for better radiation monitoring, health programs and environment remediation but many are skeptical that much will result from this. Some of the Tuaregs have turned to violent revolution against the government in the south and the French company who profit from the uranium torn from the soil of the Tuareg territories.

Arlit uranium mine from diane.sr.free.fr:

           From the days of the Hudson Bay Company, the indigenous peoples in what became the country of Canada have been move off ancestral lands, exploited for their resources, their cultures deliberately destroyed and their health, well-being and environments undermined.

           Deline is a small village of Dene people on the shore of Great Bear Lake in the North West Territories. Radium was mined on the shore of the lake from 1934 to 1939 and a uranium mine was opened in 1943 that operated until 1962. Most of the workers in the mine were men from the Dene tribe who carried bags of radioactive uranium ore up out of the mine. Radioactive tailings from the mining operation were dumped directly into the lake and were also used as landfill without regard to the health of the Dene or impact on the environment.

          The uranium mine was opened under emergency War regulation which make retroactive compensation and mitigation very difficult to achieve in court. The mine was operated by a Canadian Crown corporation and the refined uranium was exported to the United States for the Manhattan Project. Once again, the miners were given no warnings about the dangers of handling these toxic radioactive ores so they took no precautions with respect to their water and food.

           In 1975, young miners from Deline were recruited to work on a government training program. They were not given gas masks to protect them from the threat of radon gas exposure. In 1997, ten young men from Deline were recruited to help clean up some hot spots of radioactive soil in Sawmill Bay, a community in the area. They were not told of the dangers of the work but what they have learned since has them fearing serious contamination of land, water and animals in their area which threaten their health and survival.

           Deline is known as the “village of widows” because most of the men who worked as laborers in the mines have died of some form of cancer. The women were left to raise their children without their husbands and fathers to bring support the families. This has resulted in them becoming dependent on welfare. The children are raised without access to the wisdom and traditional knowledge of their missing male elders. This is destroying their ability to understand and continue their ancestral ways.

          In 1998, the Dene First Nation went to the Canadian government with a demand for compensation and mitigation. After a five-year study, the government concluded that there was insufficient evidence that the radioactivity from the mine was responsible for the high level of cancer deaths in the village. In other similar situations with uranium mines on indigenous peoples lands, there is evidence that economic considerations have been influencing government denials of health and environmental dangers of uranium mine in spite of mounting scientific validation of such dangers.

         This is not just a historical question of redressing old injuries to indigenous peoples in Canada. There are plans to expand uranium mining on tribal lands.

             When explorers and settlers arrived in North America, their diseases and wars reduced the Native American population by an estimated ninety percent over a few generations. This left vast areas of the country unpopulated and ripe for exploitation. Numerous treaties were struck with Indian Tribes giving them rights to their ancestral lands. Unfortunately, the U.S. government repeatedly broke those treaties. The Indians were eventually driven onto relative small reservations in desolate areas. The fiction has been maintained until the present that these reservations are independent sovereign nations within the United States. Indian Reservations in the United States are administered by the Bureau of Indian Affairs within the Department of the Interior.   

         After World War II, the U.S. government was moving forward with both a nuclear weapons program and a commercial nuclear power program. Uranium was needed for both these programs. In 1948, the Atomic Energy Commission created a program to stimulate domestic uranium production. Fixed prices were guaranteed for purchase of uranium, initial production from new mines would be received bonuses above the fixed purchase price and air and ground surveys were conducted in order to locate new reserves of uranium ore. A great deal of ore reserves were located in the Four Corner area, where the states of Colorado, New Mexico, Arizona and Utah meet. There Navajo Indian Reservation is located in this area.

          Many uranium mines were opened on or near the Navajo Lands. The U.S. government wanted the uranium, the Navajo were desperate for employment and the mining companies wanted the profits. Unfortunately, the contracts for the leases and royalties were poorly written and little money found its way to the Navajo Nation. The workers were not warned about the dangers of working in poorly ventilated uranium mines. Many miners suffered injury and even premature death from radiation exposure. Horrible damage was done to the environment around the mines with pollution of land, surface water and aquifers that fed wells.

         The Navajo Nation fought back against the health threat and finally won regulations for radiation exposure after thirty years. They fought over environmental damage and instituted new policies for regulating new mines and reclamation of old mining sites.  They also worked on the contracts for leases and royalties to insure that they would benefit from the extraction of resources from their lands.

         With minor variations, this pattern has been played out on other reservations where uranium ore was found. After years of exploitation, injury and environmental damage, tribes have fought back with varying success against the impact of uranium extraction and processing on their tribal lands. The U.S. government once again has failed to keep its promises and obligation to the Native Americans who live on reservations. There is much more to be done to redress this most recent injury done to Native Americans.

Great Seal of the Navajo Nation: