Atomic fallout

Plutonium (Pu) is an artificial element of atomic number 94 that has its main radioactive isotopes at 2 °Pu and Pu. The major sources of this element arise from the manufacture and detonation of nuclear weapons and from nuclear reactors. The fallout from detonations and discharges of nuclear waste are the major sources of plutonium contamination of the environment, where it is trapped in soils and plant or animal life. Since the contamination levels are generally very low, a sensitive technique is needed to estimate its concentration. However, not only the total amount can be estimated. Measurement of the isotope ratio provides information about its likely... 

It is possible to prepare very heavy elements in thermonuclear explosions, owing to the very intense, although brief (order of a microsecond), neutron flux furnished by the explosion (3,13). Einsteinium and fermium were first produced in this way they were discovered in the fallout materials from the first thermonuclear explosion (the "Mike" shot) staged in the Pacific in November 1952. It is possible that elements having atomic numbers greater than 100 would have been found had the debris been examined very soon after the explosion. The preparative process involved is multiple neutron capture in the uranium in the device, which is followed by a sequence of beta decays. Eor example, the synthesis of EM in the Mike explosion was via the production of from followed by a long chain of short-Hved beta decays,... 

Radiation Therapeutic Radioiodine Atomic fallout infections Rubella virus Cytomegalovirus Herpes virus homlnis Toxoplasmosis... 

Fallout plutonium arrives in natural waters either by direct atmospheric deposition or by erosion and/or dissolution from the land. Although in the past, this plutonium was considered to be in a refractory form due to formation within the fire ball, it seems more likely that most of the plutonium originated in the stratosphere by the decay of 239Np (from 239U formed during the detonation)(4). Deposition occurs predominantly with one or a few atoms incorporated in a raindrop. Investigations by Fukai indicate that collected rain contains soluble plutonium which has oxidation states that are almost totally Pu(V+VI)05). 

At the same time, the public s faith in science and technology was eroding. Radioactive fallout from atomic bomb tests was poisoning cows milk, and the thalidomide antinausea medicine prescribed to pregnant women in Europe had caused severe birth defects in 8000 children. Above all, the enormous growth of the chemical industry and pollution after World War II put public pressure on Congress to clean up the nation s air and water. 

Fig. 3. Graphical illustration of a mixing relationship between two end-member components in a three-isotope normalization diagram (241Am/239+240Pu vs. 23SPu/239+240Pu). It is indicated that the measured anthropogenic actinide isotope ratios are, within uncertainty, identical to the atomic weapon component, therefore clearly indicating that actinide fallout from the Chernobyl accident was insignificant in western Europe.

Table 4. Calculated fractious of U7Cs and wSr in Swiss soil samples contaminated by fallout from previous (40 years agoI atmospheric atomic bomb testing I component AI and from the 1986 Chernobyl accident (component C) (reference date I January 20031... 

Hardy, E. P. 1974. Depth Distribution of Global Fallout of 90Sr,, 37Cs and 239240Pu in Sandy Loam Soil. Fallout Program Quarterly Summary Report HASL-286. US Atomic Energy Commission, New York. 

But for chemists, the hydrogen bomb tests had a happier fallout too. Scientists at the Mike test collected coral from a nearby atoll contaminated with radioactive debris, and sent it to Berkeley for analysis. There the nuclear chemists found two new elements, with atomic numbers 99 and 100. They were named after two of the century s most creative physicists einsteinium and fermium. 

Department of Defense Land Fallout Prediction System, Defense Atomic... 

In Table IV, the atom ratio data obtained by radiochemical analysis of a series of aerial filter and fallout samples are presented. The analyses were performed by the Radiochemistry Division at Lawrence Radiation Laboratory, Livermore. The atom ratios, which we designate by rxA in... 

From atom ratios observed in local fallout and expected values for these ratios ... 

The refractory species, of which 147Nd is typical, appear not to be associated at all with the late entering crystalline population. In the local fallout, 147Nd exhibits constant specific activity 1.05 X 109 atoms/ Mg, and in the early entering glass population the refractories appear on the basis of data obtained thus far to be primarily surface distributed. 

Schwartz (4) provided the early fallout field tray information for Palanquin. He reported a fraction of total atoms produced per square foot divided by the field exposure rate at the tray locations in roentgens/ hr. at H + 1 hr. for the different nuclides studied. The trays were placed from about 2500 to 25,000 ft. from ground zero the data show no trend with distance, so the determinations for the different trays were averaged. 

The treatment of radiochemical results on fractionated fallout samples is greatly facilitated if the data are expressed in equivalent fissions. The number of equivalent fissions of a particular nuclide is the number of atoms of the fissionable material in the device which must have undergone fission to produce the amount of the radionuclide observed in the sample. If the sample contains an atoms of nuclide n (at the time of detonation), and if the fractional yield of nuclide n for the device was t/n, the number of equivalent fissions, fn, is ... 

C reaches the Earth s surface at the rate of 2.3 atoms/cm2/s after production by cosmic ray interaction in the atmosphere, corresponding to a total production of 1.4 x 1015Bq/y. 14C is also formed by the 14N(n, p) reaction by atmospheric tests of nuclear weapons. About 2.2 x 1017 Bq were made in the atmospheric test spike of the 1950s and 1960s that has been primarily transferred to the oceans and the biosphere. This means that 14C is the most significant fallout nuclide from the point of view of population dose. Nuclear power plants also release 14C as part of their normal operation contributing 0.1 x 1015 Bq/y. 

The small number of atoms involved in some radiochemical procedures can alter the expected behavior. Although time-dependent processes obeying first-order kinetics are not changed by changes in concentration, the same is not true of second-order kinetics. For example, at 10-2 M, isotopic exchange between U(IV) and U(VI) has a lifetime of 2h, whereas at 10-10M, the same lifetime is 400 d. Another example is Np(V), which is unstable with respect to disproportionation and yet jjrCi / L solutions of NpOj are stable. The extreme dilution in some solutions can mean that equilibrium is not reached due to kinetic limitations. Fallout plutonium, present in the aqueous environment at concentrations of 10 18-10 17 M, has not reached equilibrium in over 40 y. 

Fallout. See under Atomic Energy A502-L False Ogive or Ballistic Cap A483-L Felixdorf Factory Ammionals (Austrian)... 

Larsen PR, Conard RA, Knudsen K. Thyroid hypofunction appearing as a delayed manifestation of accidental exposure to radioactive fallout in a Marshallese population. In Biological Effects of Ionizing Radiation 1. Vienna International Atomic Energy Agency, 1978 101. 

The first atomic bomb was dropped on Hiroshima the morning on August 6, 1945. by a bomber plane named Enola Gay . The first effect of the explosion occurred in one tenth of a second. It was a very bright light which caused blindness and 300,000°C heat. It burnt everything within about a three kilometer diameter area. An 1,800 km/h shock wave from the explosion destroyed everything. The major and permanent effect was the radioactive fallout which started several minutes later. This terrifying bomb, which ruined Hiroshima in a few seconds, caused approximately 80,000 deaths and 100,000 wounded. 

One important chemistry fallout from the creation of cylindrical names shall arise when the two anchor atoms normally do not have a coordination greater than two — such as is the situation with oxygen. In Chapter 6, after having developed properties of the boranes and the metallocenes, cylindrical nomenclature shall be applied to some supramolecular clusters. 

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