Unformatted text preview: earth was formed about 4.5 billion years ago. Currently, the natural uranium isotopic abundances are U234, 0.0057 a/o (atom percent); U235, 0.72 a/o; and U238, 99.27 a/o. Neglecting the U234 component, how many years ago was the isotopic abundance of U235 equal to 3.0 a/o, which is the enrichment used in many nuclear power plants? [8 points] 4. Use Laplace transforms to find a time domain expression for n 3 ( t ) for general compound decay of n 1 → n 2 → n 3 where n 3 is a stable nuclide. Perform this derivation for the case of n 2 (0) ≠ 0, n 3 (0) ≠ 0 and λ 1 ≠ λ 2 . [10 points] Selected Answers: 5.2 E K (94.5% α ) = 5.687 MeV; E K (5.5% α ) = ? 5.10 (a) n = 9.32×10 10 atoms 5.12 (c) m Y90 = 1.556 μg 5.17 m C14 = 6.23 kg/yr...
View
Full Document
 Spring '06
 HOLBERT
 Uranium, K. E. Holbert, engineering homework assignment, isotopic abundance, natural uranium isotopic

Click to edit the document details