AST 248 Lecture Notes - Lecture 7: Three Mile Island Accident, Cosmic Ray, Particle Accelerator
1 Aug 2016
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Document Summary
Primordial from before the creation of the earth. C14 originally on the earth has long since decayed. Cosmic rays bombard n nuclei in atmosphere at a steady rate, converting some of them to c14. Rate of production by cosmic rays balances rate of decay, building up a steady-state abundance of. The abundances of c isotopes: c12 - 98. 89%, c13 - 1. 11% and c14 - 0. 00000000010% C12/c14 = 1 trillion: this is the ratio found in living tissue. Dead tissue has loss of c14 by radioactive decay: c14(t) = c14(0)e t/8266y. Closing of nuclear accelerator at brookhaven national lab in 1997 due to small tritium leak equivalent to amount used in exit signs. Continued reliance on coal (56%) rather than nuclear (18%) power. Loss of medical research accelerator use and user fees. Tritium radiation levels were lower than federal standards (4 mrem/yr), would have decayed before reaching groundwater.
