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all ions through twelve-times ionized uranium are included. The more highly ionized species are negligible for the temperatures and pressures being considered in this study.


                    U 0  U + + e U1+ : U2+ + e U2 +  U3+ + e






                    i+           + e


U11+   U,2  + e


(4.1)


where


  0
  U = neutral uranium U  = i-times ionized uranium

  e = electron


        The relation between the number of ions and electrons in an equilibrium ionization-recombination reaction is described by the following Saha equation (36):