Two grams of carbon from a piece of wood found in an

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Unformatted text preview: by measuring the activity of the carbon present. Two grams of carbon from a piece of wood found in an ancient temple are analyzed and found to have an activity of 15 disintegrations per minute. Estimate the approximate age of the wood, if it is assumed that the current equilibrium specific activity of C14 in carbon has been constant at 13.56 disintegrations per minute per gram. The activity A(t) created by irradiating a material in a nuclear reactor follows the equation: A(t ) = Asat (1 − e − λt ), λ = ln 2 T1 2 15 16 17 Feb. 24 Feb. 27 Mar. 1 Mar. 3 A thin gold foil (0.1 gm) consisting of the 100 percent naturally occurring Au197 isotope is irradiated to produce the Au198 isotope, which has a half life of T1/2 = 64.8 hours. 1. After 12 hours in the reactor, the activity reached is 0.90 Curies (Ci). What is the theoretical saturation activity Asat in Curies (Ci) that can be obtained in the gold foil? 2. Since the saturation activity cannot be reached, and the irradiation process is costly, the normal practice is to aim at obtaining a fraction of the saturation activity. How many irradiation hours are needed to obtain 80 percent of the saturation activity? 3. Upon withdrawing the foil from the reactor, what is the fraction of the obtained activity remaining after 324 hours outside the reactor? Mar. 6 1. Generate the decay chain for U238 using the Chart of the Nuclides. 2. Find the decay diagrams for the following isotopes of radiological concern: Radon222, Pb210 and Po210. 3. Calculate the specific activity of the alpha emission from the Po210 isotope. 4. Calculate the specific power of Po210 deposited in the lung alveoli of smokers from tobacco smoke in MeV/(sec.gm). Mar. 8 A space probe needs a Radioisotope Heating Unit (RHU) to heat its equipment in the cold of space away from the Sun. The isotope Pu238, an alpha emitter is used in space applications and can produce the needed thermal energy. For a thermal power of 50 Watts(th) what would be the weight needed for this generator in grams and in ounces? Access the Table of the Nuclides and mine for the data concerning its half-life, and the energy emitted in its alpha particle radioactive decay. Using the following table and assuming a constant consumption rate, estimate the depletion times for the world’s energy resources. Energy Sources Energy Content [1012 GJ] Fossil Fuels Coal and lignite Crude oil Natural gas Tar sands oil Shale Oil Total 18 Mar. 3 Mar. 13 Fission Fuels Uranium for U235 Converters U238, Th232 Breeders Fusion Fuels Lithium for DT Cycle Land Oceans at 0.17 ppm Li Deuterium for DD Cycle (D2O in oceans) Consumption Rates World Energy Use/y...
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This note was uploaded on 01/24/2014 for the course NPRE 402 taught by Professor Ragheb,m during the Winter '08 term at University of Illinois, Urbana Champaign.

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