Plutonium processing physical properties

Groves moved on to Berkeley more impressed with their work than his Met Lab auditors realized. I left Chicago feeling that the plutonium process seemed to ofier us the greatest chances for success in producing bomb material, he recalls. Every other process. .. depended upon the physical separation of materials having almost infinitesimal differences in their physical properties. Transmutation by chain reaction was entirely new, but the rest of the plutonium process, chemical separation, while extremely difficult and completely unprecedented, did not seem to be impossible. ... 

Breeder reactors convert nonfissionable into fissionable Pu. The material used for fission is a combination of U-235 (which undergoes fission in a chain reaction) and the more common U-238 isotope. Excess neutrons from the U-235 fission are absorbed by the U-238, converting it to the fissionable plutonium isotope Pu-239. The chemical and physical properties of Pu-239 make it very difficult and expensive to handle and process. 

It is well known that anthropogenic radionuclides such as radiocaesium and plutonium together with natural Pb are accumulated in sediments and can be used for the dating/growth rate determination of the sediments. The flux of these radionuclides depends on factors, such as physical and chemical properties, biological factors etc,. Water dams along rivers will stop the water flow and might act as effective traps by sedimentation processes and accumulate material that otherwise would be transported to the sea. 

Laboratory. The isotope produced was the 20-hour Fm. During 1953 and early 1954, while discovery of elements 99 and 100 was withheld from publication for security reasons, a group from the Nobel Institute of Physics in Stockholm bombarded with O ions, and isolated a 30-min a-emitter, which they ascribed to 100, without claiming discovery of the element. This isotope has since been identified positively, and the 30-min half-life confirmed. The chemical properties of fermium have been studied solely with tracer amounts, and in normal aqueous media only the (III) oxidation state appears to exist. The isotope and heavier isotopes can be produced by intense neutron irradiation of lower elements such as plutonium by a process of successive neutron capture interspersed with beta decays until these mass numbers and atomic numbers are reached. Twenty isotopes and isomers of fermium are known to exist. Fm, with a half-life of about 100.5 days, is the longest lived. °Fm, with a half-life of 30 min, has been shown to be a product of decay of Element 102. It was by chemical identification of Fm that production of Element 102 (nobelium) was confirmed. Fermium would probably have chemical properties resembling erbium. 

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