Lithium is the source of tritium, which is the primary ?fuel? for a dt fusion reactor. (The deuterium, which his abundant and relatively cheap, can be considered as analogous to the air required for combustion of a fossil fuel.) Compute the energy density (J/kg) of lithium with respect to dt fusion. First, ignore the difference between isotopes ⁶Li and ⁷Li, assume that one lithium atom produces one tritium atom at no energy cost, and use the fact that 17.6 MeV is emitted in dt fusion. Next improve your estimate by noting that 7.6% of naturally occuring Li is ⁶Li and 92.4% is ⁷Li. The reactions eq. (18.14)

and eq. (18.15)

are exothermic and endothermic respectively, thereby allowing you to estimate the energy required (or emitted) to convert lithium to tritium. Show that this correction to the energy density of naturally occurring lithium is ? 10% and that the result agrees with the number quoted in?

Table 36.3.

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Nth +3 Li → a +t