Albert Einstein had lead an unconventional life as an early adult falling in love with Mileva Maric whom he met in school in 1896 at the tender age of 17. The friendship slowly grew into a romance and finally a love affair leading to the birth of their first child out of wedlock in early 1902. Sadly this daughter, Lieserl, was given up for adoption and is lost to history. A year later Albert was able to marry his sweetheart in January 1903 and in May 1904 their first recognized child Hans A. Einstein was born. In 1905 Albert Einstein took a teaching position in Paris where he was befriended by Pierre and Marie Curie who were doing research into radioactivity.
Albert and Marie Einstein alternative scenarioThe next year, 1906, tragedy struck both couples when Maric Einstein was struck down by Eclampsia while pregnant with their third child. Within a few weeks of the funeral Pierre Curie was killed in a street crossing accident because as he was so often distracted by his thoughts about physics he stepped into the street and was trampled by the horses pulling a heavy freight wagon before the driver could stop. Through their mutual loss and suffering Albert Einstein and Marie Curie became even closer friends and ultimately married in 1908 creating a blended family.
Because of their close relationship Albert became exposed constantly to Marie's research on radioactivity and started thinking about ways to model the behavior of subatomic particles. At his suggestion Marie preforms a series of new experiments that lead to the discovery of Uranium Fission in 1919. Albert then spends almost two years developing the math model which proves to his satisfaction that certain heavy isotopes like the Uranium 235 nucleus are barely balanced and the impact addition of a proton at even relatively low energy is enough to cause the fission of the atom into smaller nuclei. Careful calculations have shown that over 99% of natural Uranium is the isotope 238 which will also fission, but which requires a much higher energy impact to overcome its 'natural balance of forces' in the words of Einstein.
In 1922 the British Physicist James Chadwick duplicated the Albert and Marie Einstein experiment and declared that the paper published in 1919 had completely missed the release of neutral sub-atomic particles Chadwick labels Neutrons whenever a fission event takes place in the target. Albert and Marie immediately go back to researching and in 1925 assemble their first 'pile' in the catacombs under Paris. The term Pile was chosen because of its resemblance to the Voltaic Pile invented by Alessandro Volta in 1800. Volta's pile had been a series of copper and zinc metal discs stacked with layers of brine soaked cloth separating the layers from direct contact which created an electric current. The Einstein Pile was a series Uranium and Thorium metal disks separated by thick layers of ground Anthracite coal wetted with heavy water and then hydraulically pressed into disk shaped steel housings. Under a suggestion from Marie the disks all had identical masses which meant that a thin disk of thorium was surmounted with a thick disk of pressed coal, then a thin disk of uranium and another thick disk of coal and so on to build a physical stack almost a meter in diameter and three meters tall. Each metal disk was fitted with thermocouples to keep a careful record of any temperature changes and when the pile reached nearly three meters a temperature rise was detected. The outside of the pile was encased in a thick layer of sandbags filled with borax washing salt which did an excellent job of absorbing escaping neutrons. Because of an excess of caution based on the calculation of Albert Einstein and lab tests that had shown extreme radioactivity could sicken or even kill laboratory animals the pile had been built to the 'safety limit' of two meters quickly. After that an additional stack of four layers would be added and an hour of observation would follow carefully checking the thermocouples for any sign of reaction. That first slight temperature increase had been detected after the end of work hours so the pile had been monitored overnight without any additional layers being added and the temperature had stabilized at just 10 C over room temperature.
The next day the two workers who had been on the scaffolding stacking an additional four layers onto the pile were exposed to both direct neutron radiation and the gamma and X-ray photons released by the fission deeper within the pile. Both men appeared unaffected in the first few hours after they placed the addition on top of the pile and the thermocouples showed a strong increase in the temperature within the pile. It was decided to wait until the next morning and carefully monitor the pile again before placing the next set of additional layers. When the workers arrived the next morning they appeared to have taken ill and after questioning both admitted to having vomited up their suppers after going home the night before. Fearing they might be experiencing the same radiation sickness that had been observed by the laboratory technicians Marie immediately ordered film tests to determine if the pile was emitting X-rays and all of the films with an exposure of more than a brief duration were fogged with those exposed for as long as it had taken the workers to install the previous four layers completely exposed black. Fortunately the exposure around the sides of the pile was much less after being passed through the thick layer of borax filled sand bags which kept the people to the sides of the pile safe enough in her opinion. However it was clear that sending workers to either add additional disks to the pile or to removes the last eight, which had taken the pile from an inert lump to a heat generating device that now had a core temperature approaching 230 C in some layers near the center could be vary bad for their health, at least in the short term. Because the pile appeared to have stabilized at the heat load it was producing it was decided that the safest course of action was to carefully stack more borax bags around the top of the scaffolding carefully to minimize escaping X-rays from causing danger for those working around the pile and continue monitoring the situation.
Once the pile had stabilized at 230 C core temperature nothing had seemed to happen for several days. On the fifth day of heat generation one of the steel disks of coal developed a leak and the high temperature steam generated from the remaining moisture in the coal escaped, along with the volatile gasses driven out of the coal itself as would happen in the coking process used to make metallurgical coke out of natural coal. Fortunately the hydrogen, ammonia and methane released were in small volume and did not explode but the smell was warning enough for people to keep their distance from the active pile. Ventilation fans were arranged to draw the released volatile's and any additional leaks away from the pile and dump them outside where they could disperse safely in the already stinky air of Paris. Over the next several weeks the coal disks developed leaks one by one as the internal pressure found natural faults in the containers until it was clear the core disks at the highest heat had all vented. On the 47th day after the workers had suffered radiation sickness the core temperature of the pile dropped to 229 degrees C. By day 60 it was reading 212 Celsius degrees day 120 it had fallen to 183 C. Film tests were being done on a daily basis and at that point Marie Einstein calculated that a short exposure would be quite safe. This allowed the workers to start taking the pile apart removing four layers from the top on Day 120. This caused the internal temperature to start declining more rapidly and on day 121 it was down to 175 C, the largest overnight drop seen since the exposure accident on Day 2. Careful testing on the Uranium and Thorium disks removed the day before showed that they had additional radioactivity over the natural level but were still well within safe handling limits for the workers. This testing took an additional week and it wasn't until day 132 that it was judged safe to remove the next four layers of disks with minimal exposure. The removal of the four disks which had begun the warming process over four months earlier caused the pile to cool further, and an abundance of caution left it sitting in the cooling configuration while testing was done on the thorium and uranium disks removed in this set. While these disks were also in the safe handling limits for the workers it was soon clear that they had a greater increase in radioactivity than the topmost layers had experienced. The pile temperature fell from 175 C down to 115 C but there it seemed to stabilize by the end of the second testing series. Further down the pile as layers were removed it was discovered that the uranium and thorium disks were soon beyond safe handling limits because their inherent radioactivity was greatly magnified. Fortunately the metallic layers had been in the form of 2 mm thick pieces 100 mm wide by 1000 mm long. These were separated with long tong type manipulators and placed in racks in tubs of water that both cooled and shielded them from irradiating the workers. Small sample cut from the thin bars provided a long list of chemical fragments lighter than the original Uranium and Thorium metals and quite surprisingly the Thorium samples were discovered to now contain tiny traces of Uranium where before they had been pure. At first it was suggested that somehow the materials had been accidentally mixed up in the laboratory testing, but the Uranium recovered from the Thorium was more naturally radioactive than the Uranium from the natural layers.
Albert and Marie's 1926 paper about their 'pile experiment' and the effect of 'breeding' Uranium from Thorium was considered extremely improbable by most physicists around the world. Fortunately for their reputations an American physicist, Ernest Lawrence, took it as a challenge to experiment on Thorium with high energy particles and he built the worlds first artificial particle accelerator in 1927 to do just that, bombarding natural Thorium with hydrogen ions, pure protons, instead of the lower energy alpha particles traditionally used in bombardment experiments. As a result by the end of 1927 he had confirmed that if a Thorium nuclear were struck with a Proton of precisely the right energy level it would absorb that proton and transmute from Thorium 232 into Protactinium 233 which would then itself decay via beta radiation and become Uranium 233. However if the energy was not the precisely correct range several other things might happen from as harmless as the proton bouncing off to as startling as fissioning the Thorium into two smaller nuclei. In between there was also a reaction that resulted in Uranium 232 which it turned out emitted much more dangerous X-rays as Gamma radiation.
By the time Lawrence had confirmed the observations about Thorium breeding the Einstein Curie Laboratory of Paris had also detected two new chemical elements heavier than Uranium which they dubbed Neptunium and Plutonium. These remained curiosities until the second second Paris pile was completed in late 1927. The second pile had been designed and built incorporating all the lessons learned in the construction of the first unit in 1925. In this pile the coal had been destructively distilled into coke, then ground into a flour fine powder and mixed with vegetable oil to make a very thick paste. The paste was then hydraulically pressed into the disk slices desired for the pile and baked at high temperature to create a kind of solid carbon brick with no volatile components remaining. Secondly the metallic disk layers were made of a thorium-uranium alloy instead of separate layers of metal and each segment of the pile was a sandwich of carbon on the top and bottom with the fission metal in the middle. The third change was the sandwiches were separated by a 5 mm space that allowed a layer of boron steel to be inserted between sandwiches to absorb neutrons released inside the pile and to allow air flow to pass between layers and remove heat when the control disks were withdrawn. The entire stack had been rearranged so that instead of standing three meters high it now lay on its side. To activate the pile the control disks were pulled up out of the pile by electric motors. If the power to the motors was shut off they stopped pulling up and gravity would pull the control disks back down into the pile halting further neutrons from building up a greater reaction. The shielding around the pile was also much improved and additional radiation detectors had been included beyond the simple film tests. There were now also apertures for placing sample materials in the operating pile to test them with radiation exposure safely, at least safe for the operators doing the test. Because of the way the sandwich disk pile was designed it was possible to remotely remove one sandwich and replace it with a fresh set without a human operator ever getting within several meters of the material.
The demonstration of the chain reaction in Pile 1 in 1925 and the extensive testing done with Pile 2 starting in 1927 lead to much speculation about the possibility of an uncontrolled chain reaction leading to an explosive effect by the British physicist Chadwick. Much like the way an exposed quantity of gunpowder would burn but a contained quantity of the same portion would explode. In this way it was Chadwick said that Einstein Curie Piles 'burned' thorium and uranium while a contained mass might be able to 'explode' those same metals atomically. Speculation about the usefulness of Atomic Explosives for large excavation projects was at a near fever pitch when the Wall Street crash of October 1929 initiated the Great Depression and robbed most scientists of the funding needed to develop atomic explosives. The one place where this was not true was the USSR where Stalin was the unrestrained leader and could formulate any goals he wished. Stalin had a long list of industrial goals already under way with the Five Year Plan which began in 1928. Included in that plan were not just industrialization goals but massive engineering projects that would benefit from the use of atomic explosives to ease excavations of the many canals he had planned. Accordingly while the western nations slashed research and development expenditures to the limits the USSR development team kept on working as hard as they could to develop both better E-C Piles and Chadwick explosives.
Though the first Five Year Plan failed to prove Chadwick Atomic Explosives they did boot strap the USSR by developing a successful 100 MWe air cooled graphite moderated reactor which could successfully 'burn' the thorium/uranium fuel developed by the Einstein Curie team in Paris in 1927 for up to 150 days before having to replace the sandwich with a fresh unit. They also developed the technique of rearranging the sandwich positions within the pile over time so that the freshest fuel distributed through the pile instead of concentrating it all in one place. Because of the at power refueling capability once a pile was operating it was theoretically capable of running continuously just like a coal fired power station did, simple changing the fuel as needed to maintain temperature. The USSR version of the pile remained air cooled but in their case the air was heated to extreme high temperatures before being sent through a tube boiler and making steam much like a coal or oil burning furnace would. Because of the very high energy density of a EC pile compared to a coal furnace a large number were ordered for remote locations were bringing in small quantities of fuel was a far better solution than the millions of tons of coal that would be needed to produce the same energy. This made Arkhangelsk and Murmansk the first two cities on earth to get the majority of their electricity from atomic power beginning in 1933 at the end of the first Five Year Plan.
At the beginning of the second Five year Plan on May Day 1934 Stalin revived the Roman practice of 'Decimation'. The KGB ordered the entire staff of the Atomic Explosives facility to form a line and then they separated out every tenth person from janitor through director and executed them by firing squad in front of the remaining 90 percent. The survivors were told that if they did not show progress soon another decimation would take place the following May Day. Given the options of succeed or die the survivors and the replacements sent to join the program tried everything they could test. Fortunately for their sake the testing on the expended fuel sandwiches discovered that Plutonium could be easily separated from the thorium uranium fuel metal and in mathematical models it could be made to explode in the fashion described by Chadwick in 1929. In 1935 they were able to demonstrate the worlds first atomic explosion by firing four subcritical masses of Plutonium into a fifth mass with extreme precision. The device is a monstrosity with four cannon barrels arranged like a four pointed caltrop all aimed inward and measures over 8 meters from tip to tip, but it works. Miners dig a shaft and the device is assembled at the bottom in a larger cavity. When the four canon and fired simultaneously by the expedient of electrical detonation caps all with identical length wiring the resulting explosion measures the same as 19 thousand tons of TNT chemical explosive (19 kt). The original proposal was four first a single gun firing into the target from a single direction but calculations showed that the assembly speed was too slow and predetonation would have occurred with a low explosive yield. A two canon device would have still had a high probability of failure and with all their lives at stake the researchers had gone with four canon to provide the greatest chance of success.
Testing of different expended fuel sandwiches revealed that the plutonium became more difficult to detonate the longer the fuel had been used in the reactor, and fuel exposed for longer than 120 days became very difficult to successfully use. With this in mind the USSR ordered that fuel would always be exchanged within 119 days of being added to a power station's pile, and to provide more source material many more EC pile power stations would be built. Refining the Chadwick explosive system was a priority once the first device was proven to work and it was shown that by increasing the number of gun barrels and using a higher strength explosive to propel the subcritical masses would allow the device to be made smaller. This lead to a 32 barrel design in 1937 that measured 2 meters across rather than the original 8. The individual masses were much smaller, now akin to a 20mm light canon shell than the very heavy 100 mm shells used in the original devices in 1935.
On the 19th of June 1937 the first ever military use of a Chadwick Bomb takes place when Ivan Smetlov earned his status as Hero of the Soviet Union. The components had been snuck into Bilbao a month earlier when Stalin had predicted that the Nationalists would take the city with little difficulty in the next few weeks. The way the Spanish Civil War had been developing caused Stalin to conclude that a large statement would have to be made to rally the Republican forces and dissuade the Nationalist who were being supported by the Germans and Italians. While a very tall building would have been the ideal place to set up the device such locations are always targeted by both sides as they are used by observers and snipers to give an advantage to the side holding them. Therefore the device was emplaced on the third floor of a nondescript building in an average looking district near the middle of Bilbao city. On the night of June 18th the remaining Republican forces evacuated the city under cover of darkness and at dawn the Nationalist army had flooded in. The only remaining forces on the Republican side had been a company of Red Army who manned barricades in the four blocks around the device for the purpose of drawing as many of the Nationalists close as possible. Finding the point of resistance the Nationalists ordered troops to shift in the direction of the resistance and at 12:23 on the afternoon of the 19 Smetlov observed the Nationalists over run one barricade and come pouring down the street to take the remaining barricade from behind. Doing his duty to the end he wait until the sound of gunfire died down and the occupiers started a building to building search for survivors before he detonated the Chadwick bomb. In an instant the 32 barrels fired slamming a supercritical mass together in the heart of the device. Less than a second later a light brighter than the sun appeared. In down town Bilbao the air was heated to half a million degrees and because hot air expands and shockwave raced outward smashing everything within a mile into flaming rubble and creating a firestorm. Of the 50,000 Nationalist soldiers who had rushed into the city just after dawn 35,000 were killed instantly and another 5,000 would die of burns or injuries from the shockwave thrown debris over the next week. Of the survivors about one in ten was flash blind in one or both eyes because they had the misfortune to have been facing the explosion when it went off while being far enough away to survive the blast effects.