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Fission versus Fusion:  Neutrons v. Heat

robert_steinhaus - May 22, 2013

One objection against fusion in general is that it is good in producing neutrons, rather than producing heat.

In nuclear fission the opposite is true (good at producing heat, but neutron poor).

This objection to fusion is certainly valid with regard to the release of fusion energy by the D-T fusion reaction, which is the most practical fusion reaction for magnetic plasma confinement fusion and tokamak style fusion machines.

What is not as widely recognized is that that this observation regarding the relative merits of fusion is much less valid for inertial confinement fusion, because there it is possible to use a burst of neutrons from fission or the ignition of a small amount of D-T fusion fuel to ignite a much larger amount of deuterium.

Perhaps even more attractive is the ignition of a series of thermonuclear bursts via D-D fusion in pure deuterium. It turns out that while D-D fusion is harder to initiate, only with D-D fusion are high fusion gains possible.

Use of D-D fusion also eliminates the dependence on expensive tritium (tritium is estimated by LANL to cost $30,000 a gram) and permits applications, like breeding U-233 fuel using all of the abundant flux of D-D fusion neutrons.