Equivalent fissions

Information concerning Sedan was obtained from the report by Lane (2). He reports equivalent fissions per gram for material from fallout trays between 5800 and 19,200 ft. from ground zero for a series of nuclides. The determinations show random scatter and do not indicate a trend with distance. Therefore, the values for different trays were averaged. A report by Nordyke and Williamson (3) provided the experimental determination of fallout-mass area density divided by gamma field readings in units of (kg./sq. meter)/(roentgens/hr.) over the same fallout area. These two sources provided the necessary input to calculate the fractionation indices for Sedan. 

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 ... 

Since in-house facilities for handling a large volume of samples for routine analysis were not available, the analytical work was contracted out to three commercial laboratories. We will refer to them as Laboratories A, B, and C. The contractors were selected on the basis of qualification tests which were intended to serve also for interlaboratory calibration. The results were reported to NRDL as d.p.m. or equivalent 285U thermal-neutron fissions at detonation time. All of the radiochemical data obtained from the laboratories are reported in Ref. 5. These values were punched on cards and converted by computer to equivalent fissions of the device, based on mass-chain yield values supplied by the weapons laboratories. At the same time, the calibration factors derived from qualification-test analyses were applied. Values of the ratios, 95, were formed. All of the ratios for a given nuclide i were then selected along with the corresponding values of r89t95, and the data points were fitted... 

Si(D) is specific activity, expressed in some suitable unit such as atoms of radionuclide or of fission product mass chain per unit mass of debris. A commonly used unit is equivalent fissions per gram of debris, where an equivalent fission is defined as the number of fissions that must have occurred in the device to produce the amount of a particular radionuclide observed in the sample. 

If Si is expressed in equivalent fissions per gram, then fractionation factors of any two isotopes i and j at a given particle size D are... 

Figure 4 shows the specific activity (equivalent fissions per gram, normalized to 100% fission) for 144Ce. We note without surprise that the close-in curve for Zuni lies considerably below the more distant curve. The Tewa spheres lie far above the irregulars. In varying degrees there is... 

Figure 8 is a plot of r89M4 vs. particle size. We define rlt j as the ratio of equivalent fissions of i to equivalent fissions of j. These ratios have several advantages (1) they are independent of the percent active particles, (2) they are independent of errors in weighing the samples, and (3) in a truly representative sample of weapon debris, rltj = 1 for all i and j. Figure 8 presents two surprises (1) for Zuni, r89,144 is generally lower in the more distant sample, and (2) the Zuni 85-km. curve below 150/x and the Bravo curve above 50/x have positive slopes (and appear to... 

Absolute Magnitude of Specific Activities. In the Tewa and Zuni atoll samples absolute magnitude of specific activities for particles of the same kind (e.g., irregulars) are not too different when a refractory chain such as Chain 144 is compared. The absolute magnitudes on a normalized basis are around 3 X 1015 to 5 X 1015 equivalent fissions per gram. Bravo (15 megatons on coral) and Lacrosse (40 kilotons on coral) also give similar values. 

The throwaway fuel cycle does not recover the energy values present ia the irradiated fuel. Instead, all of the long-Hved actinides are routed to the final waste repository along with the fission products. Whether or not this is a desirable alternative is determined largely by the scope of the evaluation study. For instance, when only the value of the recovered yellow cake and SWU equivalents are considered, the world market values for these commodities do not fully cover the cost of reprocessing (2). However, when costs attributable to the disposal of large quantities of actinides are considered, the classical fuel cycle has been the choice of virtually all countries except the United States. 

Al, as shown in structure 3), the molecularity (1 or 2), and the ionic form of the substrate [A for conjugate acid RC(OH)OR and B for conjugate base RCOOR]. Note that alkyl-oxygen fission constitutes nucleophilic substitution and is therefore equivalent to the classification ... 

State whether the following statements are true or false. If false, explain why. (a) The dose equivalent is lower than the actual dose of radiation because it takes into account the differential effects of different types of radiation, (b) Exposure to 1 X 1 ()x Bq of radiation would be much more hazardous than exposure to 10 Ci of radiation, (c) Spontaneous radioactive decay follows first-order kinetics, (d) Fissile nuclei can undergo fission when struck with slow neutrons, whereas fast neutrons are required to split fissionable nuclei. 

Note that in contrast with normal paraffins (Equation 10), beta fission at the branch point is exothermic, and the reaction is energetically allowed. A similar exothermic reaction can be written using C2H5 + as the reactant ion, and two other reactions equivalent to Reaction 12 can be written—namely, those with the charge in the initially formed C2i+ ion on the other two branches of the molecule. One of these other reactions will also produce a Ci4 + ion, but the other will produce a Ci5 + ion. 

Acetoin consumes 4 equivalents of V(V) to produce some biacetyl via C-H fission however, this cleavage is not accompanied by a hydronium-ion concentration dependence of the rate thereby differing from a secondary alcohol oxidation. The mechanism of breakdown of the complex is depicted as follows... 

Nurse Actually, Cdcl8 is present in fission yeast meiosis, which is a Cdc6 equivalent. I think there is more of a story here. 

During the past 35 years, natural concentrations of 3H and 85Kr, and to a much lesser extent 14C, have been masked by their man-made equivalents. In fact, natural concentrations of 88Kr are completely masked at present by the vast amount of 85Kr from artificial fission reactions. Owing to the relatively short... 

In the year 2000, 15% of the world s electric power was produced by 433 nuclear power reactors 169 located in Europe, 120 in the United States, and 90 in the Far East. These reactors consumed 6,400 tons of fresh enriched uranium that was obtained through the production of 35,000 tons of pure natural uranium in 23 different nations the main purification step was solvent extraction. In the reactors, the nuclear transmutation process yielded fission products and actinides (about 1000 tons of Pu) equivalent to the amount of uranium consumed, and heat that powered steam-driven turbines to produce 2,400 TWh of electricity in 2000. 

A single kilogram of radioactive metallic plutonium-238 produces as much as 22 million kilowatt-hours of heat energy. Larger amounts of Pu-238 produce more heat. However, Pu-238 is not fissionable, and thus it cannot sustain a chain reaction. However, plutonium-239 is fissionable, and a 10-pound ball can reach a critical mass sufficient to sustain a fission chain reaction, resulting in an explosion, releasing the equivalent of over 20,000 tons of TNT. This 10-pound ball of Pu-239 is only about one-third the size of fissionable uranium-235 required to reach a critical mass. This makes plutonium-239 the preferred fissionable material for nuclear weapons and some nuclear reactors that produce electricity. 

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