Kampers pro nuclear

Nuclear medicine

Since their introduction in 1945, nuclear explosives have been the most feared of the weapons of mass destruction, in part because of their ability to cause enormous instantaneous devastation and of the persistent effects of the radiation they emit, unseen and undetectable by unaided human senses. The Manhattan Project cost the United States $2 billion in 1945 spending power and required the combined efforts of a continent-spanning industrial enterprise and a pool of scientists, many of whom had already been awarded the Nobel Prize and many more who would go on to become Nobel Laureates. This array of talent was needed in 1942 if there were to be any hope of completing a weapon during the Second World War. Because nuclear fission was discovered in Germany, which remained the home of many brilliant scientists, the United States perceived itself to be in a race to build an atomic bomb. When the Manhattan Project began far less than a microgram of plutonium had been made throughout the world, and plutonium chemistry could only be guessed at; the numbers of neutrons released on average in U-235 and Pu-239 fissions were unknown; the fission cross sections (probabilities that an interaction would occur) were equally unknown, as was the neutron absorption cross section of carbon. experiment. Although talented people are essential to the success of any nuclear weapons program, the fundamental physics, chemistry, and engineering involved are widely under-stood; no basic research is required to construct a nuclear weapon. Therefore, a nuclear weapons project begun in 1996 does not require the brilliant scientists who were needed for the Manhattan Project.

The JCO plant needed to mix some high-purity enriched uranium oxide with nitric acid to form uranyl nitrate for shipping. The dissolving and mixing began on September 28, 1999. On the morning of September 30, 1999, three technicians, Hisashi Ouchi, Masato Shinohara, and Yutaka Yokokawa, were running fuel through the last steps of the conversion process. To speed up the process, they mixed the oxide and nitric acid in 10-liter stainless steel buckets rather than in the dissolving tank. In doing so, they followed the practice that JCO had written into its operating manual but which had not received STA approval. For convenience, they added the bucket contents directly to the 45-cm-diameter, water-jacketed precipitation tank rather than to the buffer tank. That was a crucial error because the tall, narrow geometry of the buffer tank was designed to preclude the onset of criticality. In filling the precipitation tank, the crew added seven buckets, amounting to a total of about 16 kg (35 lbs of enriched uranium, or roughly seven times more uranium than permitted under the STA license. The three technicians were working in a small processing bay. Masato Shinohara stood on a platform and was pouring the uranyl nitrate solution into the precipitation tank while Hisashi Ouchi held a glass funnel in an inlet at the top of the tank. The third technician, Yutaka Yokokawa, was seated at a desk approximately 4 meters (13 feet) away from the precipitation tank. At approximately 10:35 a.m. the technicians added the seventh bucket and saw a blue flash. The two technicians near the vessel began to experience pain, waves of nausea, some difficulty in breathing, and problems with mobility and coherence. The gamma radiation alarms activated immediately. The blue flash that they had seen was a result of the Cherenkov radiation that is emitted when nuclear fission takes place and ionizes air. The addition of the seventh bucket had caused a self-sustaining chain reaction. The mixture, in other words, had gone critical. Mixing in the precipitation tank caused the fissile uranium species to disperse so that the reaction fizzled out. However, the critical mass later reassembled, initiating another chain reaction that released more neutrons and gamma radiation. This cycle was repeated several times over many hours.